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  • 51. Brown, J
    et al.
    Jacobs, R
    Levring Jäghagen, Eva
    Umeå University, Faculty of Medicine, Department of Odontology, School of Dentistry.
    Lindh, C
    Baksi, G
    Schulze, D
    Schulze, R
    Basic training requirements for the use of dental CBCT by dentists: a position paper prepared by the European Academy of DentoMaxilloFacial Radiology2014In: Dento-Maxillo-Facial Radiology, ISSN 0250-832X, E-ISSN 1476-542X, Vol. 43, no 1, article id 20130291Article in journal (Refereed)
    Abstract [en]

    Cone beam CT (CBCT) is a relatively new imaging modality, which is now widely available to dentists for examining hard tissues in the dental and maxillofacial regions. CBCT gives a three-dimensional depiction of anatomy and pathology, which is similar to medical CT and uses doses generally higher than those used in conventional dental imaging. The European Academy of DentoMaxilloFacial Radiology recognizes that dentists receive training in two-dimensional dental imaging as undergraduates, but most of them have received little or no training in the application and interpretation of cross-sectional three-dimensional imaging. This document identifies the roles of dentists involved in the use of CBCT, examines the training requirements for the justification, acquisition and interpretation of CBCT imaging and makes recommendations for further training of dentists in Europe who intend to be involved in any aspect of CBCT imaging. Two levels of training are recognized. Level 1 is intended to train dentists who prescribe CBCT imaging, such that they may request appropriately and understand the resultant reported images. Level 2 is intended to train to a more advanced level and covers the understanding and skills needed to justify, carry out and interpret a CBCT examination. These recommendations are not intended to create specialists in CBCT imaging but to offer guidance on the training of all dentists to enable the safe use of CBCT in the dentoalveolar region.

  • 52.
    Brundin, Malin
    Umeå University, Faculty of Medicine, Department of Odontology.
    Stability of bacterial DNA in relation to microbial detection in teeth2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The fate of DNA from dead cells is an important issue when interpreting results from root canal infections analysed by the PCR technique. DNA from dead bacterial cells is known to be detectable long time after cell death and its stability is dependent on many different factors. This work investigated factors found in the root canal that could affect the recovery of microbial DNA. In an ex vivo experiment, DNA from non-viable gram-positive Enterococcus faecalis was inoculated in instrumented root canals and recovery of DNA was assessed by PCR over a two-year period. DNA was still recoverable two years after cell death in 21/25 teeth. The fate of DNA from the gram-negative bacteria Fusobacterium nucleatum and the gram-positive Peptostreptococcus anaerobius was assessed in vitro. DNA from dead F. nucleatum and P. anaerobius could be detected by PCR six months post cell death even though it was clear that the DNA was released from the cells due to lost of cell wall integrity during the experimental period. The decomposition rate of extracellular DNA was compared to cell-bound and it was evident that DNA still located inside the bacterium was much less prone to decay than extracellular DNA.

    Free (extracellular) DNA is very prone to decay in a naked form. Binding to minerals is known to protect DNA from degradation. The fate of extracellular DNA was assessed after binding to ceramic hydroxyapatite and dentine. The data showed that free DNA, bound to these materials, was protected from spontaneous decay and from enzymatic decomposition by nucleases.

    The main conclusions from this thesis were: i) DNA from dead bacteria can be detected by PCR years after cell death ex vivo and in vitro. ii) Cell-bound DNA is less prone to decomposition than extracellular DNA. iii) DNA is released from the bacterium some time after cell death. iv) Extracellular DNA bound to hydroxyapatite or dentine is protected from spontaneous decomposition and enzymatic degradation.

  • 53.
    Brundin, Malin
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Figdor, David
    Johansson, Anders
    Sjögren, Ulf
    Umeå University, Faculty of Medicine, Department of Odontology.
    Preservation of bacterial DNA by binding to dentinManuscript (preprint) (Other academic)
  • 54.
    Brundin, Malin
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Endodontics.
    Figdor, David
    Roth, Chrissie
    Umeå University, Faculty of Medicine, Department of Odontology, Endodontics.
    Davies, John K
    Sundqvist, Göran
    Umeå University, Faculty of Medicine, Department of Odontology, Endodontics.
    Sjögren, Ulf
    Umeå University, Faculty of Medicine, Department of Odontology, Endodontics.
    Persistence of dead-cell bacterial DNA in ex vivo root canals and influence of nucleases on DNA decay in vitro2010In: Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics, ISSN 1079-2104, E-ISSN 1528-395X, Vol. 110, no 6, p. 789-794Article in journal (Refereed)
    Abstract [en]

    Amplifiable DNA is preserved after cell death, but the critical determinant is the form of DNA. Free DNA undergoes spontaneous and enzymatic decomposition, whereas cell-bound E. faecalis DNA persists for long periods.

  • 55.
    Brundin, Malin
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Endodontics.
    Figdor, David
    Sundqvist, Göran
    Umeå University, Faculty of Medicine, Department of Odontology, Endodontics.
    Sjögren, Ulf
    Umeå University, Faculty of Medicine, Department of Odontology, Endodontics.
    DNA Binding to hydroxyapatite: a potential mechanism for preservation of microbial DNA2013In: Journal of Endodontics, ISSN 0099-2399, E-ISSN 1878-3554, Vol. 39, no 2, p. 211-216Article in journal (Refereed)
    Abstract [en]

    Introduction: Molecular methods are increasingly being deployed for analysis of the microbial flora in the root canal. Such methods are based on the assumption that recovered DNA is associated with the active endodontic infection, yet paleomicrobiology research is based on the recovery of ancient DNA from centuriesold tooth and bone samples, which points to considerable longevity of the DNA molecule in these tissues. The main component of dentin and bone is the mineral hydroxyapatite. This study assessed DNA binding to hydroxyapatite and whether thiS binding affinity stabilizes the DNA molecule in various media.

    Methods: DNA was extracted from Fusobacterium nucleatum and added to ceramic hydroxyapatite for 90 minutes. The DNA-bound hydroxyapatite was incubated in different media (ie, water, sera, and DNase I) for up to 3 months. At predetermined intervals, the recovery of detectable DNA was assessed by releasing the DNA from the hydroxyapatite using EDTA and evaluating the presence of DNA by gel electrophoresis and polymerase chain reaction (PCR) amplification.

    Results: When incubated with hydroxyapatite, nonamplified DNA was detectable after 3 months in water, sera, and DNase I. In contrast, DNA incubated in the same media (without hydroxyapatite) decomposed to levels below the detection level of PCR within 3 weeks, with the exception of DNA in sera in which PCR revealed a weak positive amplification product.

    Conclusions: These results confirm a specific binding affinity of hydroxyapatite for DNA. Hydroxyapatite-bound DNA is more resistant to decay and less susceptible to degradation by serum and nucleases, which may account for the long-term persistence of DNA in bone and tooth.

  • 56.
    Brundin, Malin
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Figdor, David
    Department of Microbiology, Monash University, Melbourne, Victoria, Australia.
    Sundqvist, Göran
    Umeå University, Faculty of Medicine, Department of Odontology.
    Sjögren, Ulf
    Umeå University, Faculty of Medicine, Department of Odontology.
    Preservation of Fusobacterium nucleatum and Peptostreptococcus anaerobius DNA after loss of cell viability2015In: International Endodontic Journal, ISSN 0143-2885, E-ISSN 1365-2591, Vol. 48, no 1, p. 37-45Article in journal (Other academic)
    Abstract [en]

    Aim: To investigate whether DNA from two obligate anaerobes, Fusobacterium nucleatum and Peptostreptococcus anaerobius, is recoverable after loss of cell viability induced by air exposure. Methodology: Harvested cultures of F. nucleatum and P. anaerobius were killed by exposure to air and stored in phosphate-buffered saline. Dead cells were incubated aerobically for up to 6 months. Every month, the presence of detectable DNA in the cell pellet and supernatant was assessed by conventional and quantitative PCR. Cell staining techniques were used to characterize the cell wall permeability of air-killed cells. Scanning electron microscopy was used to examine viable, freshly killed and stored cells. Results: With conventional PCR, amplifiable DNA was detectable over 6 months in all samples. Quantitative PCR showed a progressive fall in DNA concentration in nonviable cell pellets and a concomitant rise in DNA concentration in the supernatant. DNA staining showed that some air-killed cells retained an intact cell wall. After storage, SEM of both air-killed species revealed shrivelling of the cells, but some cells of P. anaerobius retained their initial form. Conclusion: Amplifiable DNA from F. nucleatum and P. anaerobius was detectable 6 months after loss of viability. Air-killed anaerobes initially retained their cell form, but cells gradually shriveled over time. The morphological changes were more pronounced with the gram-negative F. nucleatum than the gram-positive P. anaerobius. Over 6 months, there was a gradual increase in cell wall permeability with progressive leakage of DNA. Bacterial DNA was recoverable long after loss of cell viability.

  • 57. Bruno-Ambrosius, K
    et al.
    Swanholm, G
    Twetman, Svante
    Umeå University, Faculty of Medicine, Odontology, Pediatric Dentistry.
    Eating habits, smoking and toothbrushing in relation to dental caries: a 3-year study in Swedish female teenagers.2005In: International journal of paediatric dentistry, Vol. 15, no 3, p. 190-196Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: The aims of the present study were to describe eating, toothbrushing and smoking habits in a cohort of Swedish female adolescents, and to relate the findings to dental caries increment. DESIGN: The research took the form of a longitudinal study. SUBJECTS AND METHODS: The study sample consisted of a cohort of 162 girls under regular dental care, aged 12 years at baseline, who were followed for 3 years, from the sixth to the ninth grade. Eating, oral cleaning and smoking habits were self-reported three times per year through a questionnaire, and caries data at baseline and after 3 years were collected from dental records. RESULTS: The results showed significantly (P < 0.05) impaired eating habits during the study period and that adherence to regular main meals diminished. In the eighth grade, one-third of the girls skipped breakfast before school and only 50% had their free school lunch daily. The omission of breakfast and irregular main meals, as well as smoking were significantly associated with caries (decayed, missed and filled surfaces) increment in the eighth grade (odds ratio = 4.1-4.9, P < 0.05). Snacks, light meals, soft drinks and sweets were already frequently consumed at baseline and continued to be so over the years. Although > 95% of subjects reported that they brushed their teeth at least once a day, approximately 20% did not do it every evening, and this figure remained stable over the study period. However, snacks, soft drinks and sweets, and toothbrushing habits had no significant influence on caries development. CONCLUSION: Dietary advice for caries prevention in adolescent girls should focus on the importance of retaining regular main meals, and especially, not skipping breakfast.

  • 58. Buhlin, Kare
    et al.
    Holmer, Jacob
    Gustafsson, Anders
    Hörkkö, Sohvi
    Pockley, Alan Graham
    Johansson, Anders
    Umeå University, Faculty of Medicine, Department of Odontology.
    Paju, Susanna
    Klinge, Björn
    Pussinen, Pirkko
    Association of periodontitis with persistent, pro-atherogenic antibody responses2015In: Journal of Clinical Periodontology, ISSN 0303-6979, E-ISSN 1600-051X, Vol. 42, no 11, p. 1006-1014Article in journal (Refereed)
    Abstract [en]

    AIM: To study antibody responses associated with molecular mimicry in periodontitis.

    MATERIAL AND METHODS: Fifty-four periodontitis cases (mean age 54.0 years) and 44 controls (53.6 years) were examined, after which cases received periodontal treatment. Established immunoassays were used to analyse levels of antibodies against two pathogens, Aggregatibacter actinomycetemcomitans (Aa) and Porphyromonas gingivalis (Pg), heat shock proteins (Hsp), Hsp60, Hsp65, and Hsp70, and epitopes of oxidized low density lipoprotein (oxLDL) (CuOx-LDL and MDA-LDL) in plasma samples that were collected at baseline, after 3 (n=48) and 6 (n=30) months.

    RESULTS: When age, sex, smoking habit, and the number of teeth were considered in multivariate logistic regressions, Aa and Pg IgG, Hsp65-IgA, CuOx-LDL-IgG and -IgM and MDA-LDL-IgG antibody levels were associated with periodontitis, whereas Hsp60-IgG2 antibody levels were inversely associated. The Aa antibody levels significantly correlated with the levels of IgA antibodies to Hsp65 and Hsp70, and both OxLDL IgA-antibody levels. The levels of antibodies to Pg correlated with IgG antibodies to Hsp60, Hsp70 and both oxLDL antibody epitopes. None of the antibody levels changed significantly after treatment.

    CONCLUSIONS: Periodontitis is associated with persistently high levels of circulating antibodies that are reactive with pathogen- and host-derived antigens.

  • 59.
    Byström, Anders
    Umeå University, Faculty of Medicine, Department of Odontology, Endodontics. Umeå University, Faculty of Medicine, Department of Odontology, Oral Microbiology.
    Evaluation of endodontic treatment of teeth with apical periodontitis1986Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Apical periodontitis, an acute or chronic inflamination around the apex of the tooth, is caused by bacteria in the root canal. In Sweden the dentists devote around 10X of their total time to treating this disease. The treatment usually requires 3 to 5 sessions. The treatment may fail in up to 25X of the cases. In the present study various treatment regimens were evaluated. One hundred and forty singlerooted teeth with apical periodontitis were treated. The importance of mechanical instrumentation, irrigating solutions and antibacterial dressings in eliminating bacteria from the infected root canals was studied using bacteriological techniques. The healing of the apical periodontitis after treatment was followed for 2 to 5 years on recall radiographs.

    Bacteria were found in all 140 root canals at the beginning of the treatment. Most of these bacteria were anaerobes and they represented a restricted group of bacteria compared to the bacteria present at other sites in the oral cavity. Mechanical instrumentation with files and reamers in combination with saline irrigation reduced the number of bacterial cells in the root canal 100- to 1000-fold during one treatment session. Bacteria could be eliminated from about half the number of root canals if this treatment was performed at 4 sessions.

    Mechanical instrumentation and irrigation with 0.5X or 5X sodium hypochlorite solutions or with the 5X solution in combination with 15X EDTA solution wa3 more efficient and the bacteria were eliminated from about half the treated canals after one treatment session. The bacteria which persisted in the root canal after this treatment usually increased in number during the interval up to the next session and reached levels which were often as high as in the initial sample at the previous session.

    All bacteria persistent in the root canals after the previous treatment regimens were with 2 exceptions eliminated by dressing the root canals for 1 to 2 months with calcium hydroxide paste. Thirty-four out of 35 root canals treated at the first session with mechanical instrumentation, irrigation with sodium hypochlorite solution and dressed with calcium hydroxide paste were free of bacteria at the second session. Calcium hydroxide paste was superior to camphorated phenol and camphorated paramonochlorophenol as dressing.

    Healing of 79 out of the 140 treated teeth was followed for 2 to 5 years. The majority of the lesions healed completely or decreased in size in such a way that they could be expected to heal. There was no or only an insignificant decrease in the size of the lesions in 5 cases. In 2 of these cases bacteria were demonstrated in the periapical tissues and in a third case dentin chips. Periapical lesions may thus fail to heal in a few cases due to an establishment of bacteria outside the root canal, and in that site the bacteria are inaccessible to conventional endodontic treatment.

    The present study showed that treatment of the majority of infected non-vital teeth can be completed in only 2 sessions, if mechanical instrumentation, sodium hypochlorite irrigation and calcium hydroxide dressing are combined.

  • 60.
    Bäckman, Birgitta
    Umeå University, Faculty of Medicine, Department of Odontology, Pediatric Dentistry.
    Amelogenesis imperfecta: an epidemiologic, genetic, morphologic and clinical study1989Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Amelogenesis imperfecta (AI) is a genetically determined enamel defect characterized by genetic and clinical heterogeneity .

    The prevalence and incidence of AI were established in the county of Västerbotten, northern Sweden, in 3-19-yr-olds born 1963-79, as were the mode of inheritance and clinical manifestation of AI. The distribution of the inorganic component in the enamel of AI teeth was studied as well as the surface morphology and other morphological details, and the findings were correlated to genetic and clinical data.

    AI was diagnosed in 79 children and adolescents (index cases). The prevalence in the study population was 1.4:

    1 000. The mean yearly incidence 1963-79 was 1.3:1 000.

    The inheritance patterns for AI were established in 78 index cases from 51 families. Pedigree and segregation analyses suggested autosomal dominant (AD) inheritance in 3 3 families, autosomal recessive (AR) in six families, and X- linked recessive in two families; in ten families only sporadic cases were found. In one of the families with an AD inheritance pattern, X-linked dominant was a possible alternative.

    Examination of the families of the 78 index cases revealed 107 new cases of AI. The hypoplastic form was seen in 72% of all diagnosed cases and the hypomineralization form in 28% of the cases.

    A further classification of the clinical manifestations led to the identification of eight clinical variants. In 3 3 of the 51 families the same clinical variant was found in all affected members. In eight families affected members were assigned to different clinical variants. In three families with an X-linked inheritance pattern for AI, the clinical manifestation differed between women and men due to lyo- nization. Among the remaining five families, with an AD inheritance pattern for AI, variants clinically characterized by hypoplasia as well as variants characterized by hypomineralization were found in three families; in the other two families the clinical manifestation varied within the same main form of AI, i.e. hypoplasia or hypomineralization.

    Hypoplasia as well as hypomineralization were observed microradiographically in the enamel of most of the examined teeth. These findings were supported by scanning electron microscopy (SEM).

    Both clinically and microradiographically as well as by SEM, similar variants of AI were found as AD and AR traits and/or among the sporadic cases. In the families with AI as an X-linked trait the genetic hypothesis was confirmed by the clinical, microradiographic and scanning electron microscopic findings.

  • 61. Cagar, E
    et al.
    Kavaloglu, SC
    Kuscu, OO
    Sandalli, N
    Lif-Holgerson, Pernilla
    Umeå University, Faculty of Medicine, Department of Odontology, Pediatric Dentistry.
    Twetman, Svante
    Effect of chewing gums containing xylitol or probiotic bacteria on salivary mutans streptococci and lactobacilli2007In: Clinical Oral Investigations, ISSN 1432-6981, E-ISSN 1436-3771, Vol. 11, no 4, p. 425-429Article in journal (Refereed)
    Abstract [en]

    The aim was to evaluate the effect of xylitol and probiotic chewing gums on salivary mutans streptococci (MS) and lactobacilli (LB). The material consisted of 80 healthy young adults (21-24 years) who volunteered after informed consent. They were assigned by random into one of four parallel study groups: A, probiotic gum group; B, xylitol gum group; C, probiotic + xylitol gum group; and D, placebo gum group. The gums were taken three times daily after meals, and the intervention period was 3 weeks. The probiotic gums contained two strains of Lactobacilli reuteri (ATCC 55730 at a dose of 1 x 10(8) CFU/gum and ATCC PTA 5289 at a dose of 1 x 10(8) CFU/gum), and each pellet of the xylitol gum contained approximately 1.0 g xylitol as single sweetener. Pretreatment and posttreatment samples of stimulated whole saliva were collected and quantified for MS and LB with chair-side kits. A statistically significant reduction (p < 0.05) of salivary MS was displayed in group A and B after the intervention when compared with baseline. A similar but nonsignificant tendency was seen in group C. No alterations of salivary LB was demonstrated in any group. In conclusion, daily chewing on gums containing probiotic bacteria or xylitol reduced the levels of salivary MS in a significant way. However, a combination of probiotic and xylitol gums did not seem to enhance this effect.

  • 62. Cagetti, MG
    et al.
    Fadini, L
    Pariset, P
    Strohmenger, L
    Twetman, Svante
    Umeå University, Faculty of Medicine, Odontology, Pediatric Dentistry.
    Chlorhexidine concentration in saliva after topical treatment with an antibacterial dental varnish.2004In: American journal of dentistry, Vol. 17, no 3, p. 196-8Article in journal (Refereed)
    Abstract [en]

    PURPOSE: To evaluate the salivary levels of chlorhexidine (CHX) after a single professional treatment with an antibacterial dental varnish (Cervitec) containing 1% CHX and 1% thymol. METHODS: Unstimulated whole saliva from 21 healthy young adults was collected at baseline and up to 24 hours after treatment at designated time intervals and the CHX levels in saliva were quantified with high-performance liquid chromatography. Post-treatment saliva samples were added to suspensions of mutans streptococci and supragingival dental plaque for a growth inhibition. RESULTS: CHX concentration in saliva showed a peak value (76.5 microg/ml) after 5 minutes followed by a slow decrease with time. The elevation was statistically significant (P < 0.05) up to 4 hours after the application of the varnish and the recorded values were back to baseline levels after 24 hours. The 2- and 4-hour post-treatment saliva samples inhibited growth of mutans streptococci by 46% and 33%, respectively.

  • 63. Chiang, Huei-Min
    et al.
    Tranaeus, Sofia
    Sunnegårdh Grönberg, Karin
    Umeå University, Faculty of Medicine, Department of Odontology.
    Caries as experienced by adult caries active patients: a qualitative study2019In: Acta Odontologica Scandinavica, ISSN 0001-6357, E-ISSN 1502-3850, Vol. 77, no 1, p. 15-21Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: In the western world, increased oral health has resulted in a skewed occurrence of caries disease where relatively few individuals now account for most caries disease. This study examines how adults with recurrent caries activity experience caries disease and treatment.

    MATERIALS AND METHODS: The study is based on qualitative data from individual interviews, which were subjected to qualitative content analysis. The interviews were semi-structured and thematic and an interview guide was used that consisted of two main areas with open ended questions. Meaning units were condensed and labelled with a code which preserved the core content of the reduced text. Codes were assigned to different subcategories according to their similarities or differences. Subcategories formed categories which describe the manifest content of the text.

    RESULTS: The domain "experience with caries" consisted of four subcategories that formed the main category Caries - an unwelcomed acquaintance. The domain "experience with caries treatment" consisted of three subcategories that formed the category Caries treatment - pain for gain.

    CONCLUSION: Comprehensive non-operative treatment and close follow-ups should precede restorations; this would probably gain insight in how to avoid new cavities to a greater extent. If to be supportive, information and advice about self-care given to individuals with recurrent cavities should be delivered with respect to the patient's feelings about their experience of dental caries.

  • 64.
    Claesson, Rolf
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Gudmundson, Jan
    Östersund, Sweden.
    Höglund-Åberg, Carola
    Umeå University, Faculty of Medicine, Department of Odontology.
    Haubek, Dorte
    Aarhus, Denmark.
    Johansson, Anders
    Umeå University, Faculty of Medicine, Department of Odontology.
    Detection of a 640-bp deletion in the Aggregatibacter actinomycetemcomitans leukotoxin promoter region in isolates from an adolescent of Ethiopian origin2015In: Journal of Oral Microbiology, ISSN 2000-2297, E-ISSN 2000-2297, Vol. 7, article id 26974Article in journal (Refereed)
    Abstract [en]

    The expression of the leukotoxin of Aggregatibacter actinomycetemcomitans is regulated by the leukotoxin promoter. A 530-bp deletion or an 886-bp insertion sequence (IS) element in this region has earlier been described in highly leukotoxic isolates. Here, we report on highly leukotoxic isolate with a 640-bp deletion, which was detected in an adolescent of Ethiopian origin.

  • 65.
    Claesson, Rolf
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Höglund-Åberg, Carola
    Umeå University, Faculty of Medicine, Department of Odontology.
    Haubek, Dorte
    Johansson, Anders
    Umeå University, Faculty of Medicine, Department of Odontology.
    Age-related prevalence and characteristics of Aggregatibacter actinomycetemcomitans in periodontitis patients living in Sweden2017In: Journal of Oral Microbiology, ISSN 2000-2297, E-ISSN 2000-2297, Vol. 9, article id 1334504Article in journal (Refereed)
    Abstract [en]

    Background: The presence of Aggregatibacter actinomycetemcomitans in patients with periodontitis has been extensively studied for decades. Objective: To study the prevalence of A. actinomycetemcomitans in younger and older periodontitis patients and to genetically characterize isolates of this bacterium. Design: Data from microbiological analyses of 3459 subgingival plaque samples collected from 1445 patients, 337 'younger' patients (<= 35 yrs) and 1108 'older' patients (>35 yrs) during 15 years (2000-2014), has been summerized. Isolates of A. actinomycetemcomitans were serotyped, leukotoxin promoter typed (JP2 and non JP2) and arbitrarily primed PCR (APPCR) genotyped. The origin of the JP2 genotype detected in the study population was determined. Results: The prevalence of A. actinomycetemcomitans was higher among younger than older patients and samples from the younger patients contained higher proportions of the bacterium. Serotype b was more prevalent among younger patients and the majorty of these isolates was from the same AP-PCR genotype. The JP2 genotype was detected in 1.2% of the patients, and the majority of these carriers were of non-African origin. Conslusions: For presence and charcteristics of A. actinomycetemcomitans in clinical samples the age of the carriers were a discriminating factor. Additional, apparently non- African carriers of the JP2 genotype of A. actinomycetemcomitans were identified.

  • 66.
    Claesson, Rolf
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Kanasi, Eleni
    Umeå University, Faculty of Medicine, Department of Odontology.
    Anders, Johansson
    Umeå University, Faculty of Medicine, Department of Odontology.
    Sotirios, Kalfas
    School of Dentistry, Aristotle University of Thessaloniki, Thessaloniki, Greece.
    A new cleavage site for elastase within the complement component 32010In: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS), ISSN 0903-4641, E-ISSN 1600-0463, Vol. 118, no 10, p. 765-768Article in journal (Refereed)
    Abstract [en]

    The lysosomal enzyme elastase was earlier shown to cleave the complement molecule C3. During somepreliminary experiments on the interactions of certain pathogenic bacteria with the innate defencemechanisms, we observed C3 cleavage, in the presence of elastase, to fragments not previouslydescribed. To elucidate this proteolytic reaction, the present study was conducted. Degradation of C3in mixtures with elastase or cathepsin G was detected by an immunoblot procedure using anti-C3c andanti-C3d antibodies after separating the proteins by SDS-PAGE. Certain C3 fragments were analysedfor amino acid sequence. The results revealed the existence of a cleavage site for elastase at the positionalanine1350 ⁄ lysine1351 of the C3 molecule, which has not been previously described. The fragmentresulted from this cleavage has a size of about 39 kDa and it contains a part or the whole of C3d. Thiscleavage was distinct from the one previously described at position 987 ⁄ 988, which gives a 34 kDaC3d-containing fragment.

  • 67.
    Claesson, Rolf
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Lagervall, Maria
    Department of Periodontology at Skanstull, Stockholm County Council, Stockholm, Sweden.
    Höglund-Åberg, Carola
    Umeå University, Faculty of Medicine, Department of Odontology.
    Johansson, Anders
    Umeå University, Faculty of Medicine, Department of Odontology.
    Haubek, Dorte
    Department of Pediatric Dentistry, School of Dentistry, Aarhus, Denmark.
    Detection of the highly leucotoxic JP2 clone of Aggregatibacter actinomycetemcomitans in members of a Caucasian family living in Sweden2011In: Journal of Clinical Periodontology, ISSN 0303-6979, E-ISSN 1600-051X, Vol. 38, no 2, p. 115-121Article in journal (Refereed)
    Abstract [en]

    Background: Carriers of the JP2 clone of Aggregatibacter actinomycetemcomitans exhibit an enhanced risk for developing aggressive periodontitis compared with individuals carrying non-JP2 clones. While the JP2 clone is almost exclusively detected among adolescents of African descent, reports on Caucasians colonized with the JP2 clone are remarkably few.

    Objective: The aim of this paper is to report on the history of periodontal disease and microbiological findings in a Caucasian family.

    Material and Methods: A. actinomycetemcomitans and other periodontitis-associated bacterial species in subgingival plaque samples were quantified by conventional culture technique. Leucotoxin promoter typing, serotyping and further characterizations of A. actinomycetemcomitans isolates were performed by PCR. DNA sequencing of the pseudogene, hbpA was performed to determine the origin of the detected JP2 clones. Further, genetically ancestry testing of family members was carried out.

    Results: The JP2 clone was detected in samples from two of the family members, a 33-year-old daughter and her 62-year-old mother. Relationship of their JP2 clones with JP2 clone strains from the Mediterranean area of Africa was indicated. Genotyping confirmed the Caucasian origin of all family members.

    Conclusions: Caucasian JP2 carriers exist and older subjects can carry the JP2 clone of A. actinomycetemcomitans.

  • 68. Conaway, H. Herschel
    et al.
    Henning, Petra
    Lerner, Ulf H.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Vitamin A metabolism, action, and role in skeletal homeostasis2013In: Endocrine reviews, ISSN 0163-769X, E-ISSN 1945-7189, Vol. 34, no 6, p. 766-797Article in journal (Refereed)
    Abstract [en]

    Vitamin A (retinol) is ingested as either retinyl esters or carotenoids and metabolized to active compounds, such as 11-cis-retinal, which is important for vision, and all-trans-retinoic acid (ATRA), which is the primary mediator of biological actions of vitamin A. ATRA binds to retinoic acid receptors (RARs), which heterodimerize with retinoid X receptors (RXRs). RAR-RXR heterodimers function as transcription factors, binding RAR responsive elements in promoters of different genes. Numerous cellular functions, including bone cell functions, are mediated by vitamin A; however, it has long been recognized that increased levels of vitamin A can have deleterious effects on bone resulting in increased skeletal fragility. Bone mass is dependent on the balance between bone resorption and bone formation. A decrease in bone mass may be caused by either an excess of resorption or decreased bone formation. Early studies indicated that the primary skeletal effect of vitamin A was to increase bone resorption, but later studies have shown that vitamin A can not only stimulate the formation of bone resorbing osteoclasts, but inhibit their formation as well. Effects of vitamin A on bone formation have not been studied in as great a detail and are not as well characterized as effects on bone resorption. Several epidemiological studies have shown an association between vitamin A, decreased bone mass, and osteoporotic fractures, but the data are not conclusive, for other studies have found no associations, and some studies have suggested that vitamin A primarily promotes skeletal health. In this presentation, we have summarized how vitamin A is absorbed, metabolized, and functions intracellularly. Vitamin A deficiency and excess are introduced, and detailed descriptions of clinical and pre-clinical studies of the effects of vitamin A on the skeleton are presented.

  • 69.
    Cricchio, Giovanni
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Imburgia, Mario
    Sennerby, Lars
    Lundgren, Stefan
    Umeå University, Faculty of Medicine, Department of Odontology.
    Immediate Loading of Implants Placed Simultaneously with Sinus Membrane Elevation in the Posterior Atrophic Maxilla: a Two-Year Follow-Up Study on 10 Patients2014In: Clinical Implant Dentistry and Related Research, ISSN 1523-0899, E-ISSN 1708-8208, Vol. 16, no 4, p. 609-617Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Clinical studies on immediate loading of implants in the posterior atrophic maxilla are rare.

    PURPOSE: The study aims to evaluate immediate loading of implants placed with sinus membrane elevation without additional grafting material for bone augmentation of the maxillary sinus floor.

    MATERIALS AND METHODS: The study group comprised of 10 patients in whom a total of 10 maxillary sinus floor augmentations were performed. A total of 21 dental implants (1 to 4) were inserted through the residual bone to protrude into the maxillary sinus under the elevated sinus membrane. The implant site was underprepared to improve primary stability. All the implants were inserted with a torque insertion no less than 20 Ncm. Implants were loaded immediately after surgery with a screw-retained temporary acrylic restoration. Intraoral X-rays were taken at implant insertion, after 6 months loading, and after 1st and 2nd year of loading. Resonance frequency analysis (RFA) was performed at the time of initial placement and after 6 months of functional loading. RESULTS: RFA after implant insertion gave an implant stability quotient (ISQ) level with a range from 62 to 72. All implants remained clinically stable during the follow-up period of 2 years. Radiography demonstrated on average 5.7 ± 3.4 mm of intrasinus new bone formation after 6 months of implant loading. RFA measurements showed ISQ mean values of 67 (range: 62-72) and 68 (range: 62-71) at placement and after 6 months of loading, respectively.

    CONCLUSION: Within the limits of this case series report, it is concluded that maxillary sinus membrane elevation with simultaneous placement and immediate loading of implants without the use of any additional grafting material shows predictable results after 2 years of functional loading. Moreover, evidence of intrasinus bone formation around the implants was found in all patients. Further studies are needed to study the influence of immediate loading on the mineralization of bone forming at dental implant sites.

  • 70.
    Cricchio, Giovanni
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Oral and Maxillofacial Surgery.
    Palma, Vinicious Canavarros
    Faria, Paolo E P
    de Olivera, José Americo
    Lundgren, Stefan
    Umeå University, Faculty of Medicine, Department of Odontology, Oral and Maxillofacial Surgery.
    Sennerby, Lars
    Salata, Luiz A
    Histological outcomes on the development of new space-making devices for maxillary sinus floor augmentation2011In: Clinical Implant Dentistry and Related Research, ISSN 1523-0899, E-ISSN 1708-8208, Vol. 13, no 3, p. 224-230Article in journal (Refereed)
    Abstract [en]

    Background: Previous studies have pointed out that the mere elevation of the maxillary sinus membrane promotes bone formation without the use of augmentation materials.

    Purpose: This experimental study aimed at evaluating if the two-stage procedure for sinus floor augmentation could benefit from the use of a space-making device in order to increase the bone volume to enable later implant installation with good primary stability.

    Materials and Methods: Six male tufted capuchin primates (Cebus apella) were subjected to extraction of the three premolars and the first molar on both sides of the maxilla to create an edentulous area. The sinuses were opened using the lateral bone-wall window technique, and the membrane was elevated. One resorbable space-making device was inserted in each maxillary sinus, and the bone window was returned in place. The animals were euthanatized after 6 months, and biopsy blocks containing the whole maxillary sinus and surrounding soft tissues were prepared for ground sections.

    Results: The histological examination of the specimens showed bone formation in contact with both the schneiderian membrane and the device in most cases even when the device was displaced. The process of bone formation indicates that this technique is potentially useful for two-stage sinus floor augmentation. The lack of stabilization of the device within the sinus demands further improvement of space-makers for predictable bone augmentation.

    Conclusions: It is concluded that (1) the device used in this study did not trigger any important inflammatory reaction; (2) when the sinus membrane was elevated, bone formation was a constant finding; and (3) an ideal space-making device should be stable and elevate the membrane to ensure a maintained connection between the membrane and the secluded space.

  • 71.
    Cricchio, Giovanni
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Oral and Maxillofacial Surgery.
    Palma, Vinícius Canavarros
    Faria, Paulo E P
    de Oliveira, José Américo
    Lundgren, Stefan
    Umeå University, Faculty of Medicine, Department of Odontology, Oral and Maxillofacial Surgery.
    Sennerby, Lars
    Salata, Luiz A
    Histological findings following the use of a space-making device for bone reformation and implant integration in the maxillary sinus of primates2009In: Clinical Implant Dentistry and Related Research, ISSN 1523-0899, E-ISSN 1708-8208, Vol. 11, no suppl 1, p. e14-e22Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Previous studies have shown that membrane elevation results in predictable bone formation in the maxillary sinus provided that implants can be placed as tent poles. In situations with an extremely thin residual crest which impairs implant placement, it is possible that a space-making device can be used under the sinus membrane to promote bone formation prior to placement of implants.

    PURPOSE: The present study was conducted to test the hypothesis that the use of a space-making device for elevation of the sinus membrane will result in predictable bone formation at the maxillary sinus floor to allow placement of dental implants.

    MATERIALS AND METHODS: Eight tufted capuchin primates underwent bilateral sinus membrane elevation surgery, and a bioresorbable space-making device, about 6 mm wide and 6 mm in height, was placed below the elevated membrane on the sinus floor. An oxidized implant (Nobel Biocare AB, Gothenburg, Sweden) was installed in the residual bone protruding into the created space at one side while the other side was left without an implant. Four animals were sacrificed after 6 months of healing. The remaining four animals received a second implant in the side with a space-making device only and followed for another 3 months before sacrifice. Implant stability was assessed through resonance frequency analysis (RFA) using the Osstell (Osstell AB, Gothenburg, Sweden) at installation, 6 months and 9 months after the first surgery. The bone-implant contact (BIC) and bone area inside the threads (BA) were histometrically evaluated in ground sections.

    RESULTS: Histologically there were only minor or no signs of bone formation in the sites with a space-making device only. Sites with simultaneous implant placement showed bone formation along the implant surface. Sites with delayed implant placement showed minor or no bone formation and/or formation of a dense fibrous tissue along the apical part of the implant surface. In the latter group the apical part of the implant was not covered with the membrane but protruded into the sinus cavity.

    CONCLUSIONS: The use of a space-making device, with the design used in the present study, does not result in bone formation at the sinus floor. However, membrane elevation and simultaneous placement of the device and an implant does result in bone formation at the implant surface while sites with implants placed 6 months after membrane elevation show only small amounts of bone formation. It is suggested that lack of stabilization of the device and/or a too extensive elevation of the membrane may explain the results.

  • 72.
    Cricchio, Giovanni
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Oral and Maxillofacial Surgery.
    Sennerby, Lars
    Department of Biomaterials, Institute for Clinical Sciences, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden .
    Lundgren, Stefan
    Umeå University, Faculty of Medicine, Department of Odontology, Oral and Maxillofacial Surgery.
    Sinus bone formation and implant survival after sinus membrane elevation and implant placement: a 1- to 6-year follow-up study2011In: Clinical Oral Implants Research, ISSN 0905-7161, E-ISSN 1600-0501, Vol. 22, no 10, p. 1200-1212Article in journal (Refereed)
    Abstract [en]

    Objectives: To investigate the long-term clinical and radiographic results of the maxillary sinus membrane elevation technique where implants were inserted in a void space created by the elevation of the sinus membrane without adding any graft material.

    Materials and methods: A total of 84 patients were subjected to 96 membrane elevation procedures and simultaneous placement of 239 implants. Changes of intra-sinus and marginal bone height in relation to the implants were measured in intraoral radiographs taken at insertion, after 6 months of healing, after 6 months of loading and then annually. Computerized tomography was performed pre-surgically and 6 months post-surgically. Resonance Frequency Analyses measurements were performed at the time of implants placement, at abutment connection and after 6 months of loading. The implant follow-up period ranged from a minimum of one to a maximum of 6 years after implants loading.

    Results: All implants were stable after 6 months of healing. A total of three implants were lost during the follow-up period giving a survival rate of 98.7%. Radiography demonstrated on average 5.3±2.1 mm of intra-sinus new bone formation after 6 months of healing. RFA measurements showed adequate primary stability (implant stability quotient 67.4±6.1) and small changes over time.

    Conclusion: Maxillary sinus membrane elevation and simultaneous placement of implants without the use of bone grafts or bone substitutes result in predictable bone formation with a high implant survival rate of 98.7% during a follow-up period of up to 6 years. The intra-sinus bone formation remained stable in the long-term follow-up. It is suggested that the secluded compartment allowed for bone formation according to the principle of guided tissue regeneration. The high implant survival rate of 98.7% indicated that the implants sufficiently supported the fixed bridges throughout the study period. This technique reduces the risks for morbidity related to harvesting of bone grafts and eliminates the costs of grafting materials.

  • 73.
    Cricchio, Giovanni
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Sennerby, Lars
    Lundgren, Stefan
    Umeå University, Faculty of Medicine, Department of Odontology.
    Sinus floor augmentation without bone grafting2019In: The sinus bone graft / [ed] Ole T. Jensen, Batavia: Quintessence Publishing , 2019, 3, p. 66-72Chapter in book (Refereed)
    Abstract [en]

    As research proceeds on treatment of the resorbed posterior maxilla, new techniques and innovations continue to be adopted to solve this clinical problem. While the previous edition of this book provided detailed information on the types of grafting materials and procedures available at the time, this completely revised version looks to the future with new strategies for treatment, some of which avoid grafting altogether. This book not only reviews the time-tested lateral window approach for sinus elevation and grafting but also describes a variety of techniques to approach the sinus transcrestally with or without grafting material. One section of the book is devoted entirely to the different types of implants and implant placement techniques available, many of which are designed specifically to avoid sinus elevation. In addition to clinical case studies and descriptions of how to perform specific surgical procedures, this book includes discussions on the science of bone formation and how continued research brings us closer every day to the ultimate goal of using tissue engineering to completely regenerate new teeth.

  • 74.
    Crossner, Claes-Göran
    Umeå University, Faculty of Medicine, Department of Odontology, Oral Microbiology.
    Försök till tidig diagnos av kariessjukdomen1980Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The aim of the present thesis was to find a test for prediction of caries activity which would be useful in routine clinical work.Correlations between oral health, general health, food habits and socioeconomic conditions were investigated in 4- and 8-year-old children. It was found that the salivary secretion rate and the prevalence of oral lactobacilli were factors which might be useful in caries prediction.In 5- and 8-year-old children negative correlations between caries frequency and secretion rate, pH and buffer effect of saliva were demonstrated. However, these parameters showed a wide range of variation.A dip-slide test (Dentocult®), for determination of the number of lactobacilli in saliva, were investigated. The test proved to be reliable for determining of the number of lactobacilli in saliva.The clinical use of information on salivary secretion rate and number of lactobacilli in saliva in prediction of caries activity was examined in 115 14-year-old children over a period of 64 weeks. The number of lactobacilli in saliva, but not the salivary secretion rate, was correlated to caries activity. The number of lactobacilli in saliva seems to reflect the frequency of ingested fermentable carbohydrates and indirectly the risk for initiation of carious lesions. However, when the lactobacillus test is used it is important that there are no such areas of microbial retention on the teeth, as open cavities, poorly executed conservations, dentures or orthodontic bands. The lactobacillus test would make it possible to individualize prophylactic caries treatment.

  • 75.
    Dahlén, Gunnar
    et al.
    Göteborgs Universitet.
    Claesson, Rolf
    Umeå University, Faculty of Medicine, Department of Odontology.
    Höglund Åberg, Carola
    Umeå University, Faculty of Medicine, Department of Odontology, School of Dentistry.
    Haubek, Dorte
    Aarhus University Denmark.
    Johansson, Anders
    Umeå University, Faculty of Medicine, Department of Odontology, School of Dentistry.
    Kwamin, Francis
    Ghana University, Ghana.
    Subgingival bacteria in Ghanaian adolescents with or without progression of attachment loss2014In: Journal of Oral Microbiology, ISSN 2000-2297, E-ISSN 2000-2297, Vol. 6, article id 23977Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: This study describes subgingival bacterial profiles associated with clinical periodontal status in Ghanaian adolescents with or without progression of attachment loss.

    MATERIALS AND METHODS: Among 500 adolescents included in a cohort study, 397 returned 2 years later for a periodontal re-examination, including full-mouth CAL measurements. At follow-up, a subgroup of 98 adolescents was also subjected to bacterial sampling with paper points at four periodontal sites (mesial aspect of 11, 26, 31, and 46) and analyzed with the checkerboard DNA-DNA hybridization technique against DNA-probes from nine periodontitis-associated bacterial species.

    RESULTS: The 98 Ghanaian adolescents examined in the present study were similar to the entire group examined at the 2-year follow-up with respect to age, gender, and CAL ≥3 mm. A high detection frequency of Fusobacterium nucleatum and Prevotella intermedia (>99%) using checkerboard analysis was found, while for Aggregatibacter actinomycetemcomitans the detection frequency was <50%. A strong correlation was found at the individual level between the presence of P. intermedia and the total CAL change, and P. intermedia and Porphyromonas gingivalis were strongly correlated with a change in CAL and probing pocket depth (PPD) at the sampled sites. In a linear regression model, a significant discriminating factor for the total CAL change in the dentition during the 2-year follow-up period was obtained for P. intermedia and public school.

    CONCLUSION: This study indicates that subgingival bacterial species other than A. actinomycetemcomitans, for example, P. intermedia, have a significant association with periodontal breakdown (change in CAL) in Ghanaian adolescents with progression of periodontal attachment loss.

  • 76.
    Danielsson, Karin
    Umeå University, Faculty of Medicine, Department of Odontology. Umeå University, Faculty of Medicine, Department of Medical Biosciences.
    Oral lichen planus: studies of factors involved in differentiation, epithelial mesenchymal transition and inflammation2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Background: Lichen planus is a chronic inflammation of skin and mucosa with unknown cause. Oral Lichen Planus, OLP, affects around 2% of the population. Autoimmunity has been suggested as a possible cause as the disease has autoimmune features such as female predominance, cyclic nature and cytotoxic T-cell infiltrate. It has been suggested that the intense inflammatory response seen in OLP is caused by factors on the keratinocyte surface triggering the immune system. Chronic inflammation is one of the hallmarks of oral lichen planus and chronic inflammation is connected to increased risk of tumor development. WHO classifies OLP as a potentially malignant condition with increased risk of developing Squamous cell carcinoma of head and neck, SCCHN, but malignant transformation of OLP is a matter of controversy. The aim of these studies was to further elucidate the autoimmune and premalignant character of OLP. Factors involved in malignant transformation, autoimmunity and inflammation were analyzed in normal oral mucosa, OLP and SCCHN. Factors studied were the signal transducers of Transforming growth factor-β the Smad proteins, microRNAs, COX-2, the receptor CXCR-3 and its ligands CXCL-10 and -11 and ELF-3.

    Material and methods: In the study on Smad protein expression formalin fixed and paraffin embedded biopsies from normal oral mucosa, OLP and SCCHN was used. For the remaining studies fresh frozen biopsies from OLP and normal controls was used. All of the fresh frozen OLP samples and their controls were micro dissected to be able to analyze the epithelial part only as well as sections of the whole biopsy. Methods used are immunohistochemistry, qRT-PCR and Western blot.

    Results: Analyses of smad proteins expression showed a clear increase of smad3 and smad7 in OLP compared to normal oral mucosa. The expressions of smad proteins in the tumors were more heterogeneous. Some of the SCCHN samples showed a similar expression as OLP while others did not. Micro RNA analyzes showed that miR-21 and miR-203 was significantly increased in OLP epithelium compared to normal oral epithelium while the expression of miR-125b and their potential targets p53 and p63 was decreased in OLP. The presence of COX-2 was significantly higher in OLP than normal controls. At the same time the expression of miR-26b, a suggested repressor of COX-2 was decreased in OLP compared to normal mucosa. The receptor CXCR-3 and its ligands CXCL-10 and -11 were increased in OLP. Expressions of the differentiation involved factor ELF-3 mRNA as well as protein were decreased in OLP.

    Conclusion: The factors studied are involved in differentiation, malignant transformation and inflammation. Some of the results in these studies indicate a similar expression pattern for OLP and SCCHN. Several of the factors studied are involved in differentiation and their deregulation suggests a disturbed differentiation pattern and this could indicate a premalignant character of OLP but malignant transformation of OLP lesions are relative rare. A lot of these factors are also involved in inflammatory processes and connected to autoimmune diseases and their deregulation in OLP could also support an autoimmune cause of the disease. Based on our studies a suggestion is that the disturbed differentiation pattern triggers the intense immune response directed against the epithelial cells seen in OLP.

  • 77.
    Danielsson, Karin
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Ebrahimi, Maijd
    Umeå University, Faculty of Medicine, Department of Odontology.
    Wahlin, Ylva-Britt
    Umeå University, Faculty of Medicine, Department of Odontology.
    Nylander, Karin
    Umeå University, Faculty of Medicine, Department of Medical Biosciences.
    Boldrup, Linda
    Umeå University, Faculty of Medicine, Department of Medical Biosciences.
    Increased levels of COX-2 in oral lichen planus supports an autoimmune cause of the disease2012In: Journal of the European Academy of Dermatology and Venereology, ISSN 0926-9959, E-ISSN 1468-3083, Vol. 26, no 11, p. 1415-1419Article in journal (Refereed)
    Abstract [en]

    Background: Oral lichen planus (OLP) is a chronic inflammatory disease for which the pathogenesis is not fully understood. OLP has autoimmune features and auto immunity has been suggested as a potential cause, whereas WHO has classified OLP as a premalignant condition. Association between chronic inflammation and cancer is known and chronic inflammation is one of the characteristics of OLP. A protein connected to inflammation and suggested to be involved in cancer development is cyclooxygenase-2 (COX-2) which can be inhibited by microRNA-26b (miR-26b).

    Objective: The aim was to map levels of COX-2 and miR-26b in OLP lesions to see if there was any correlation between expression of COX-2 and its regulator miR-26b in OLP.

    Methods: In biopsies from 20 OLP patients and 20 age and gender-matched controls laser- micro dissection of epithelium was performed. Quantitative RT-PCR, immunohistochemistry and Western blot were used in the analysis.

    Results: Levels of COX-2 mRNA were significantly higher while levels of miR-26b were significantly lower in OLP lesions compared to controls. Using immunohistochemistry normal oral mucosa samples did not show any expression of COX-2 while OLP samples expressed the protein. No COX-2 protein was detectable with Western blot.

    Conclusion: Increased expression of COX-2 and decreased expression of miR-26b in OLP suggests both to play a role in OLP. COX-2 has been connected to both malignant development and autoimmunity but as malignant development of OLP is quite rare we suggest that the increased levels of COX-2 seen here support an autoimmune cause of the disease.

  • 78.
    Danielsson, Karin
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Ebrahimi, Majid
    Umeå University, Faculty of Medicine, Department of Odontology.
    Nylander, Elisabet
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Dermatology and Venerology.
    Wahlin, Ylva Britt
    Umeå University, Faculty of Medicine, Department of Odontology.
    Nylander, Karin
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Alterations in factors involved in differentiation and barrier function in the epithelium in oral and genital lichen planus2017In: Acta Dermato-Venereologica, ISSN 0001-5555, E-ISSN 1651-2057, Vol. 97, no 2, p. 214-218Article in journal (Refereed)
    Abstract [en]

    Lichen planus is a chronic recurrent inflammatory disease affecting both skin and mucosa, mainly in oral and/or genital regions. Keratinocytes go through a well-regulated process of proliferation and differentiation, alterations in which may result in defects in the protective epithelial barrier. Long-term barrier impairment might lead to chronic inflammation. In order to broaden our understanding of the differentiation process in mucosal lichen planus, we mapped the expression of 4 factors known to be involved in differentiation. Biopsies were collected from oral and genital lichen planus lesions and normal controls. Altered expression of all 4 factors in epithelium from lichen planus lesions was found, clearly indicating disturbed epithelial differentiation in lichen planus lesions.

  • 79.
    Danielsson, Karin
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Oral Diagnostics.
    Ebrahimi, Majid
    Umeå University, Faculty of Medicine, Department of Odontology, Oral Diagnostics. Umeå University, Faculty of Medicine, Department of Odontology, Endodontics.
    Wahlin, Ylva-Britt
    Umeå University, Faculty of Medicine, Department of Odontology, Oral Diagnostics. Umeå University, Faculty of Medicine, Department of Odontology, Prosthetic Dentistry.
    Nylander, Karin
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Boldrup, Linda
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Reply to increased levels of COX-2 and oral lichen planus by P.D. Pigatto, F. Spaderi, G.P. Bombeccari, G. Guzzi by Danielsson et al2013In: Journal of the European Academy of Dermatology and Venereology, ISSN 0926-9959, E-ISSN 1468-3083, Vol. 27, no 3, p. 395-396Article in journal (Refereed)
  • 80.
    Danielsson, Karin
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Nylander, Elisabet
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Dermatology and Venerology.
    Sjöström, Mats
    Umeå University, Faculty of Medicine, Department of Odontology.
    Ebrahimi, Majid
    Umeå University, Faculty of Medicine, Department of Odontology.
    Epstein-Barr virus is not detected in mucosal lichen planus2018In: Medicina Oral, ISSN 1698-4447, E-ISSN 1698-6946, Vol. 23, no 5, p. e560-e563, article id 22617Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Lichen planus (LP) is a chronic inflammatory, immunological, mucocutaneous disease can affect skin, genital and oral mucosa. Oral lichen planus (OLP) is the most common noninfectious, chronic inflammatory oral disease affecting 1-2% of the general adult population. World Health Organization (WHO) classifies OLP as a potentially malignant disorder. Epstein Barr virus or human herpesvirus-4, is a member of the herpes virus family and one of the most ubiquitous viruses known to human, infecting approximately 90% of the world's adult population. The virus often infects B lymphocytes resulting in a wide spectrum of mucocutaneous and systemic diseases, ranging from mild lesions to aggressive malignancies. The aim of this study was to investigate expression of the EBV encoded RNAs EBER1 and EBER2 in oral and genital lichen planus and compare results with normal tissues in situ hybridization which is considered the golden standard for detection of EBER.

    MATERIAL AND METHODS: A total of 68 biopsies, 25 oral LP, 26 genital LP, 10 oral controls and finally 7 genital controls were analysed using situ hybridization.

    RESULT: All samples had RNA as shown by the control slide, whereas no case contained neither EBER1 nor EBER2.

    CONCLUSIONS: Based on results from our study EBV is not involved in aetiology of lichen planus.

  • 81.
    Danielsson, Karin
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Olah, Joakim
    Umeå University, Faculty of Medicine, Department of Odontology, School of Dentistry.
    Zohori-Zangeneh, Reza
    Umeå University, Faculty of Medicine, Department of Odontology, School of Dentistry.
    Nylander, Elisabet
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Dermatology and Venerology.
    Ebrahimi, Majid
    Umeå University, Faculty of Medicine, Department of Odontology.
    Increased expression of p16 in both oral and genital lichen planus2018In: Medicina Oral, ISSN 1698-4447, E-ISSN 1698-6946, Vol. 23, no 4, p. e449-e453Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Lichen Planus, LP, is an inflammatory disease of possible autoimmune origin affecting mainly oral and genital mucosa and skin. According to the WHO oral LP is considered a potentially malignant disorders. The p16 tumour suppressor protein can act as an inhibitor of cyclin dependent kinases 4 and 6 and thus down regulate cell cycle progression. Since the discovery of p16 several studies have evaluated its expression in various forms of human cancers. The aim of this study was to evaluate and compare the expression of p16 in oral and genital LP and corresponding healthy mucosa.

    MATERIAL AND METHODS: A total of 76 cases of oral LP (OLP), 34 cases of genital LP (GLP), 12 cases of healthy oral and 9 cases of healthy genital mucosa were analysed by the use of immunohistochemistry.

    RESULTS: Data showed p16 to be highly expressed in both oral and genital LP, higher than in oral (p=0.000), and genital controls (p=0.002).

    CONCLUSIONS: Results suggest that the over-expression of p16 seen in LP play a part in the histopathology of the disease.

  • 82.
    Danielsson, Karin
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Wahlin, Ylva Britt
    Umeå University, Faculty of Medicine, Department of Odontology.
    Coates, PJ
    Division of Medical Sciences, University of Dundee, Ninewells Hospital and Medical School, Dundee, UK.
    Nylander, Karin
    Umeå University, Faculty of Medicine, Department of Medical Biosciences.
    Increased expression of Smad proteins, and in particular Smad3, in oral lichen planus compared to normal oral mucosa2010In: Journal of Oral Pathology & Medicine, ISSN 0904-2512, E-ISSN 1600-0714, Vol. 39, no 9, p. 639-644Article in journal (Refereed)
    Abstract [en]

    Backgound: Oral lichen planus (OLP) is a chronic inflammatory disease of the oral mucosa which the World Health Organisation (WHO) considers a premalignant condition. One step in malignant development is so called epithelial mesenchymal transition (EMT), a process whereby epithelial cells acquire mesenchymal characteristics. EMT occurs during embryogenesis and wound healing but also in some human diseases such as cancer and fibrosis. A factor known to induce EMT is transforming growth factor-beta (TGF-beta), which uses the Smad proteins as mediators for its signalling. TGF-beta is also often over-expressed in squamous cell carcinoma of the head and neck (SCCHN).

    Methods: In the present study we mapped expression of Smad proteins in OLP lesions by immunohistochemistry, and compared to expression in normal and sensitive oral mucosa. The latter group of patients had developed SCCHN after shorter or longer periods of diffuse oral symptoms. The aim was to see if there were any signs of EMT related changes in the OLP lesions, as judged by changes in the TGF-beta pathway.

    Conclusion: Changes in the TGF-beta pathway related to EMT are seen in the very earliest stages of oral malignancy and become more severe as lesions progress.

  • 83.
    Danielsson, Karin
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Oral Diagnostics.
    Wahlin, Ylva-Britt
    Umeå University, Faculty of Medicine, Department of Odontology, Oral Diagnostics. Umeå University, Faculty of Medicine, Department of Odontology, Prosthetic Dentistry.
    Boldrup, Linda
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Nylander, Karin
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Decreased expression of ELF-3 indicating disturbed differentiation in oral lichen planus2012In: Oral Diseases, ISSN 1354-523X, E-ISSN 1601-0825, Vol. 18, no Special Issue, Suppl. 1, p. 20-20Article in journal (Other academic)
  • 84.
    Danielsson, Karin
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology. Umeå University, Faculty of Medicine, Department of Medical Biosciences.
    Wahlin, Ylva-Britt
    Umeå University, Faculty of Medicine, Department of Odontology.
    Gu, Xiaolian
    Umeå University, Faculty of Medicine, Department of Medical Biosciences.
    Boldrup, Linda
    Umeå University, Faculty of Medicine, Department of Medical Biosciences.
    Nylander, Karin
    Umeå University, Faculty of Medicine, Department of Medical Biosciences.
    Altered expression of miR-21, miR-125b, and miR-203 indicates a role for these microRNAs in oral lichen planus2012In: Journal of Oral Pathology & Medicine, ISSN 0904-2512, E-ISSN 1600-0714, Vol. 41, no 1, p. 90-95Article in journal (Refereed)
    Abstract [en]

    Background: Oral lichen planus (OLP), which is a chronic inflammatory disease of the oral mucosa with unknown etiology, affects about 2% of the population. MicroRNAs are small non-coding RNAs involved in normal processes such as development and differentiation as well as progression of human diseases. The aim of this study was to investigate the expression of miR-21, miR-125b, and miR-203 and to compare RNA levels of their potential targets, the tumor suppressor p53 and its relative p63, both known to be deregulated in OLP.

    Methods: In biopsies from 20 patients with OLP and 20 age- and sex-matched healthy controls, epithelium was laser dissected and analyzed for the expression of miR-21, miR-125b, miR-203, p53, and p63 using qRT/PCR.

    Results: Increased expression of miR-21 and miR-203, decreased expression of miR-125, and down-regulation of p53 and ΔNp63 RNA were seen in OLP compared to normal oral mucosa. When comparing microRNA expression to levels of p53 and p63 RNA, a significant negative correlation was seen between ΔNp63 and miR-203 and between miR-21 and p53, respectively.

    Conclusion: Results indicate a role for the studied microRNAs in changes seen in OLP.

  • 85.
    Danielsson Niemi, Liza
    Umeå University, Faculty of Medicine, Odontology, Cariology.
    Host ligands and oral bacterial adhesion: studies on phosphorylated polypeptides and gp-340 in saliva and milk2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Infectious diseases e.g. gastric ulcer, caries and perodontitis, are caused by bacteria in a biofilm. Adhesion of bacteria to host ligands e.g. proteins, polypeptides and glycoproteins, is a key event in biofilm formation and colonization of surfaces such as mucosa and tooth tissues. Thus, host ligands could contribute to the susceptibility to infectious diseases. The general aim of this doctoral thesis was to study the effect of phosphorylated polypeptides and gp-340 in saliva and milk on oral bacterial adhesion and aggregation.

    Statherin is a non-glycosylated, phosphorylated polypeptide in saliva. The polypeptide inhibits precipitation and crystal growth of calcium phosphate and mediates adhesion of microorganisms. By using a hybrid peptide construct, the domain for adhesion of Actinomyces isolated from human infections and from rodents was found to reside in the C-terminal end, and the adhesion was inhibitable. With alanine substitution the peptide recognition epitope in the C-terminal end was delineated to Q and TF, where QAATF was an optimal inhibitory peptide. In contrast, human commensal Actinomyces bound to the middle region in a non-inhibitable fashion. Gp-340 is another protein in saliva, and it is a large, multifunctional glycoprotein. Four novel size variants (I-IV) of salivary gp-340 were distinguished within individuals, and their glycoforms were characterized. All four size variants were identical in the N-terminal amino acid sequence and shared core carbohydrates. Low-glyco lung gp-340, high-glyco saliva gp-340, and size variants I-III aggregated bacteria differently. Human milk, which shares many traits with saliva, could inhibit adhesion of Streptococcus mutans to saliva-coated hydroxyapatite (s-HA), a model for teeth, in an individually varying fashion. Human milk caseins, lactoferrin, secretory IgA, and IgG inhibited the binding avidly. By using synthetic peptides the inhibitory epitope in b-casein was mapped to a C-terminal stretch of 30 amino acids. Inhibition by human milk, secretory IgA and the b-casein-derived inhibitory peptide was universal among a panel of mutans streptococci.

    The main conclusions are: (i) statherin mediates differential binding of commensal versus infectious Actinomyces strains with small conformation-dependent binding epitopes, (ii) salivary gp-340 has individual polymorphisms that at least affect binding of bacteria, (iii) human milk inhibits S. mutans adhesion to s-HA in an individually varying fashion, and the C-terminal end of human milk β-casein is one inhibitory component. Together these results suggest that the studied host ligands can influence the composition of the oral biofilm. Statherin may protect the host from colonization of bacteria associated with infections. Gp-340 size variants may affect functions related to host innate immune defences such as interactions with a wide array of bacteria, and human milk may have a protective effect in infants from colonization of mutans streptococci.

  • 86.
    Danielsson Niemi, Liza
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Cariology.
    Hernell, Olle
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Johansson, Ingegerd
    Umeå University, Faculty of Medicine, Department of Odontology, Cariology.
    Human milk compounds inhibiting adhesion of mutans streptococci to host ligand-coated hydroxyapatite in vitro2009In: Caries Research, ISSN 0008-6568, E-ISSN 1421-976X, Vol. 43, no 3, p. 171-178Article in journal (Refereed)
    Abstract [en]

    Acquisition of mutans streptococci at an early age is a risk factor for later caries development. Following our recent finding that human milk may inhibit adhesion of Streptococcus mutans the aim of the present study was to identify compounds in human milk preventing adhesion of mutans streptococci to saliva- or gp340-coated hydroxyapatite (s-HA and gp340-HA) using an in vitro model system. Superdex 200 fractions of human milk and purified proteins were screened for binding inhibition of the S. mutans strain Ingbritt. Avid inhibition was seen to both s-HA and gp340-HA for caseins, lactoferrin, IgA and IgG, and moderate inhibition for alpha-lactalbumin and bile salt-stimulated lipase, whereas albumin and lysozyme had no effect. The inhibitory epitope in beta-casein was delineated to its C-terminal LLNQELLNPTHQIYPVTQPLAPVHNPISV stretch by use of synthetic peptides. Similarly, a peptide (SCKFDEYFSQSCA) corresponding to the human lactoferrin stretch that is highly homologous to the previously shown inhibitory stretch of bovine lactoferrin was found to inhibit S. mutans Ingbritt binding. Inhibition by human milk, IgA, and the inhibitory beta-casein peptide was universal among 4 strains of S. mutans (Ingbritt, NG8, LT11, JBP) and 2 strains of S. sobrinus (6715 and OMZ176). IgG inhibited 4, alpha-lactalbumin 3 and lactoferrin 2 of these 6 strains. It was also confirmed that none of the milk components coated on HA mediated S. mutans Ingbritt adhesion, which was consistent with the finding that no milk protein was recognized on Western blots by gp340/DMBT1 monoclonal antibodies.

  • 87.
    Danielsson Niemi, Liza
    et al.
    Umeå University, Faculty of Medicine, Odontology, Cariology.
    Johansson, Ingegerd
    Umeå University, Faculty of Medicine, Odontology, Cariology.
    Salivary statherin peptide-binding epitopes of commensal and potentially infectious Actinomyces spp. delineated by a hybrid peptide construct2004In: Infection and Immunity, ISSN 0019-9567, E-ISSN 1098-5522, Vol. 72, no 2, p. 782-787Article, review/survey (Refereed)
    Abstract [en]

    Adhesion of microorganisms to host receptor molecules such as salivary statherin molecules is a common event in oral microbial colonization. Here we used a hybrid peptide construct (with both a hydroxyapatite-binding portion and a test peptide portion) to map the interaction of Actinomyces species (and Candida albicans) with statherin. Adhesion to hybrid peptides and truncated statherin variants revealed three binding types, types I to III. (i) Type I strains of rat, hamster, and human infection origins bound C-terminal-derived QQYTF and PYQPQY peptides. The QQYTF peptide inhibited statherin binding for some strains but not for others. (ii) Type II strains of human and monkey tooth origins bound middle-region-derived YQPVPE and QPLYPQ peptides. Neither strain was inhibited by soluble peptides. (iii) Type III strains of human infection origins (and C. albicans) did not bind to either statherin-derived peptides or truncated statherin. Moreover, the type I strains inhibited by QQYTF were also inhibited by TF and QAATF peptides and were detached from statherin by the same peptides. In conclusion, it is suggested that commensal and potentially infectious microorganisms bind middle or C-terminal statherin differently and that other microbes might require discontinuous epitopes.

  • 88. Davidson, Thomas
    et al.
    Rohlin, Madeleine
    Hultin, Margareta
    Jemt, Torsten
    Nilner, Krister
    Sunnegårdh Grönberg, Karin
    Umeå University, Faculty of Medicine, Department of Odontology.
    Tranaeus, Sofia
    Nilsson, Mats
    Reimbursement systems influence prosthodontic treatment of adult patients2015In: Acta Odontologica Scandinavica, ISSN 0001-6357, E-ISSN 1502-3850, Vol. 73, no 6, p. 414-420Article in journal (Refereed)
    Abstract [en]

    Objective. To evaluate the influence of reimbursement system and organizational structure on oral rehabilitation of adult patients with tooth loss. Materials and methods. Patient data were retrieved from the databases of the Swedish Social Insurance Agency. The data consisted of treatment records of patients aged 19 years and above claiming reimbursement for dental care from July 1, 2007 until June 30, 2009. Before July 1, 2008, a proportionately higher level of subsidy was available for dental care in patients 65 years and above, but thereafter the system was changed, so that the subsidy was the same, regardless of the patient's age. Prosthodontic treatment in patients 65 years and above was compared with that in younger patients before and after the change of the reimbursement system. Prosthodontic treatment carried out in the Public Dental Health Service and the private sector was also analyzed. Results. Data were retrieved for 722,842 adult patients, covering a total of 1,339,915 reimbursed treatment items. After the change of the reimbursement system, there was a decrease in the proportion of items in patients 65 years and above in relation to those under 65. Overall, there was a minimal change in the proportion of treatment items provided by the private sector compared to the public sector following the change of the reimbursement system. Conclusions. Irrespective of service provider, private or public, financial incentive such as the reimbursement system may influence the provision of prosthodontic treatment, in terms of volume of treatment.

  • 89.
    de Almeida, F. J. Mota
    et al.
    Department of Endodontics, Tandvårdens Kompetenscentrum, Norrbottens County Counci, Luleå; Department of Oral-and-Maxillofacial Radiology, Odontologiska fakulteten, Malmö University, Malmö, Sweden.
    Knutsson, K.
    Department of Oral-and-Maxillofacial Radiology, Odontologiska fakulteten, Malmö University, Malmö, Sweden.
    Flygare, Lennart
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    The impact of cone beam computed tomography on the choice of endodontic diagnosis2015In: International Endodontic Journal, ISSN 0143-2885, E-ISSN 1365-2591, Vol. 48, no 6, p. 564-572Article in journal (Refereed)
    Abstract [en]

    Aim To determine whether the outcome of cone beam computed tomography (CBCT) examinations performed in accordance with the European Commission guidelines in a clinical setting has an impact on choosing diagnoses in endodontics. Methodology A prospective observational study was conducted. Fifty-three consecutive patients (81 teeth) from two different endodontic specialist clinics in Sweden were followed. After performing a thorough clinical examination (based on the history, clinical findings, and diagnostic tests such as intra-oral radiography), the examiner wrote down a preliminary diagnosis before CBCT examination. After the CBCT examination, a new diagnosis was made by the same examiner. Both the pre- and the post-CBCT examination diagnoses were plotted according to patients and teeth. The CBCT examinations were performed using similar equipment and protocols that were standardized amongst the clinics. Results The diagnoses were changed for at least one tooth in 22 patients (41%); overall, the diagnoses were changed for 28 teeth (35%). Conclusion CBCT has a substantial impact on diagnostic thinking in endodontics when used in accordance with the European Commission guidelines.

  • 90. de Almeida, Fernando J. Mota
    et al.
    Kivijarvi, Kristina
    Roos, Göran
    Umeå University, Faculty of Medicine, Department of Medical Biosciences.
    Nylander, Karin
    Umeå University, Faculty of Medicine, Department of Medical Biosciences.
    A case of disseminated histoplasmosis diagnosed after oral presentation in an old HIV-negative patient in Sweden2015In: Gerodontology, ISSN 0734-0664, E-ISSN 1741-2358, Vol. 32, no 3, p. 234-236Article in journal (Refereed)
    Abstract [en]

    Histoplasmosis is an endemic disease in various regions such as North America and South-East Asia but remains rare in Europe. Disseminated histoplasmosis is unusual in HIV-negative patients. Here, we describe a case of disseminated histoplasmosis in an HIV-negative patient diagnosed after oral presentation.

  • 91. De Bruyn, H
    et al.
    Collaert, B
    Lindén, U
    Flygare, L
    A comparative study of the clinical efficacy of Screw Vent implants versus Brånemark fixtures, installed in a periodontal clinic.1992In: Clinical Oral Implants Research, ISSN 0905-7161, E-ISSN 1600-0501, Vol. 3, no 1, p. 32-41Article in journal (Refereed)
    Abstract [en]

    The clinical success of 85 Screw Vent and 107 Brånemark implants, consecutively installed in a private periodontal clinic under the same conditions and by the same operator, is compared. Mobile implants were removed and considered as failures. Intra-oral radiographs were assessed for the presence of peri-implant radiolucencies and for analysis of bone loss after functional loading. 85 Screw Vent implants were installed in 31 patients. Of 23 implants installed in 9 mandibles, none failed after 16.8 (range 12-25) months of function. Of 62 Screw Vent implants installed in 23 maxillae, 6 failed at abutment connection, 1 failed after 2 months and 2 after 13 months of function. The absolute failure rate after 13.2 (range 6-24) months was 9/62. Mean loss of bone was 1.47 mm (-1.0- +4) after 12 months of functional loading. 107 Brånemark fixtures were installed in 25 patients. Of 51 fixtures inserted in 12 mandibles, none failed; of 56 fixtures installed in 13 maxillae 1 failed before and 2 failed during abutment connection. The absolute failure is 3/56. All remaining fixtures were immobile after loading. 13 fixtures were more than 6 months in function. Only short-term comparison between both systems is possible because the observation time is longer for the Screw Vent implants. In the 1st year, only 1 implant system was available to the periodontist. Short-term comparison reveals 11.3% versus 5.3% of cumulative failure after 6 months for the Screw Vent and Brånemark implants, respectively. The results indicate that clinical efficacy is as effectively obtained with Screw Vent as with Brånemark implants in the mandible. The outcome of treatment with Screw Vent implants in the maxilla seems less predictable.

  • 92. de Gee, Anton J
    et al.
    Kleverlaan, Cees J
    van Dijken, Jan
    Umeå University, Faculty of Medicine, Odontology, Dental Hygiene.
    Dentala kompositer: betydelsen av polymerisationskrympning och genererade spänningar2007In: Tandläkartidningen, ISSN 0039-6982, Vol. 99, no 3, p. 40-44Article in journal (Refereed)
    Abstract [en]

    During the curing shrinkage of adhesively bonded resin composites tensile stresses develop, which are exerted back onto the cavity walls. the extent of the stress determines whether part of the tooth structure will fracture. Unfortunately, shrinkage stress values are not available for the general practitioner. Recommendations are therefore made for the use of low shrinkage and/or low shrinkage stress resin ccomposites for different cavity types. In the current study, thirty resin composites were evaluated for shrinkage and shrinkage stress. The majorityof the composites compplied with the hypothesis that a low shrinkage is accompanied with a high shrinkage stress and visa-versa. Some composite materials showed both a low shrinkage and a low shrinkage stress and are thus proposed to give the least problems with respect to marginal seal and enamel fracture.

  • 93. de Oliveira Neto, Patricio José
    et al.
    Cricchio, Giovanni
    Umeå University, Faculty of Medicine, Department of Odontology.
    Hawthorne, Ana Carolina
    Okamoto, Roberta
    Sennerby, Lars
    Lundgren, Stefan
    Umeå University, Faculty of Medicine, Department of Odontology, Oral and Maxillofacial Surgery.
    Salata, Luiz Antonio
    Tomographic, histological, and immunohistochemical evidences on the use of N-butyl-2-cyanoacrilate for onlay graft fixation in rabbits2012In: Clinical Implant Dentistry and Related Research, ISSN 1523-0899, E-ISSN 1708-8208, Vol. 14, no 6, p. 861-871Article in journal (Refereed)
    Abstract [en]

    Background: The bone tissue responses to Cyanoacrylate have been described in the literature, but none used N-butyl-2-cyanoacrilate (NB-Cn) for bone graft fixation.

    Purpose: The aims of the study were: (a) to analyze the bone grafts volume maintenance fixed either with NB-Cn or titanium screw; (b) to assess the incorporation of onlay grafts on perforated recipient bed; and (c) the differences of expression level of tartrate-resistant acid phosphatase (TRAP) protein involved in bone resorption.

    Materials and Methods: Eighteen New Zealand White rabbits were submitted to calvaria onlay grafting on both sides of the mandible. On one side, the graft was fixed with NB-Cn, while on the other hand the bone graft was secured with an osteosynthesis screw. The computed tomography (CT) was performed just after surgery and at animals sacrifice, after 1 (n = 9) and 6 weeks (n = 9), in order to estimate the bone grafts volume along the experiments. Histological sections of the grafted areas were prepared to evaluate the healing of bone grafts and to assess the expression of TRAP protein.

    Results: The CT scan showed better volume maintenance of bone grafts fixed with NB-Cn (p ≤ 0.05) compared with those fixed with screws, in both experimental times (analysis of variance). The immunohistochemical evaluation showed that the TRAP expression in a 6-week period was significantly higher compared with the 1-week period, without showing significant difference between the groups (Wilcoxon and Mann-Whitney). Histological analysis revealed that the NB-Cn caused periosteum damage, but provided bone graft stabilization and incorporation similar to the control group.

    Conclusion: The perforation provided by screw insertion into the graft during fixation may have triggered early revascularization and remodeling to render increased volume loss compared with the experimental group. These results indicate that the NB-Cn possesses equivalent properties to titanium screw to be used as bone fixation material in osteosynthesis.

  • 94. Derand, Tore
    et al.
    Molin, Margareta
    Umeå University, Faculty of Medicine, Odontology, Prosthetic Dentistry.
    Kvam, Ketil
    Bond strength of composite luting cement to zirconia ceramic surfaces.2005In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 21, no 12, p. 1158-62Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: To evaluate the bond strength of dental resin agent to zirconia ceramic after surface pre-treatment with different techniques. METHODS: Specimens of hot isostatic pressed yttrium-oxide-partially-stabilized zirconia blocks (ZF) were fabricated (Procera Zircon, Nobel Biocare, Sweden) and compared to glossy dense zirconia blocks (ZG). Four groups of specimens with different surface treatment were prepared. Group I: ZF (n = 5) and ZG (n = 5) without any pre-treatment, Group II: ZF-s (n = 5) and ZG-s (n = 5) treated with silane solution, Group III: ZF-P (n = 10) and ZG-P (n = 10) treated with RF plasma spraying (hexamethyldisiloxane) using a reactor (Plasma Electronic, Germany), Group IV: ZF-p (n = 10) and ZG-p (n = 10) treated with micro pearls of low fusing porcelain (720 degrees C) on the surfaces. Composite cylinders (Charisma, Hereus Kulzer, Dormagen, Germany) were luted with Variolink II (Ivoclar-Vivadent, Schaan, Liechtenstein) to the test specimens. The specimens were then stored in air for 1 h before shear loading in a universal testing machine (LRX, Lloyd Instruments, Farnham, England) until failure. RESULTS: No statistical difference was found between the untreated ZF and ZG specimens (Group I) neither between the specimens treated with silane (Group II). Plasma spraying treatment improved bond strength by a factor of three (p < 0.001). Treatment with low fusing porcelain micro pearls increased the bond strength by a factor of 10 compared to untreated surfaces (p < 0.001). No significant difference was seen between the surfaces treated ZF-p and ZG-p specimens. The thickness of the glass pearls layer did not exceed 5 microm. SEM showed dense grain borders of ZF and a flat glossy texture of ZG. SIGNIFICANCE: Treatment of zirconia ceramic surfaces with plasma spraying or a low fusing porcelain pearl layer significantly increased the bond strength of resin cement to the ceramic surface.

  • 95.
    Dijken, Jan W.V. van
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Ardlin, Berit
    Umeå University, Faculty of Medicine, Department of Odontology.
    Tillberg, Anders
    Umeå University, Faculty of Medicine, Department of Odontology.
    Wahlin, Ylwa Britt
    Umeå University, Faculty of Medicine, Department of Odontology.
    Berglund, Anders
    Umeå University, Faculty of Medicine, Department of Odontology.
    Sunnegårdh-Grönberg, Karin
    Umeå University, Faculty of Medicine, Department of Odontology.
    Lindberg, Anders
    Umeå University, Faculty of Medicine, Department of Odontology.
    Molin, Margareta
    Umeå University, Faculty of Medicine, Department of Odontology.
    Sjögren, Göran
    Umeå University, Faculty of Medicine, Department of Odontology.
    Hulterström, Anna Karin
    Umeå University, Faculty of Medicine, Department of Odontology.
    Samarbete breddar forskning: Oral Biomaterialgruppen, Umeå2008In: Tandläkartidningen, Vol. 100, no 5, p. 74-79Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Vid institutionen för odontologi vid Umeå Universitet finns en lång tradition av biomaterialforskning. För drygt två år sedan samlades större delen av den forskningen i ett vetenskapligt nätverk. Här beskrivs ett axplock av det breda forskningsarbetet.

  • 96. Doğan, B
    et al.
    Kipalev, AS
    Okte, E
    Sultan, N
    Asikainen, Sirkka
    Umeå University, Faculty of Medicine, Odontology. Umeå University, Faculty of Medicine, Odontology.
    Consistent intrafamilial transmission of Actinobacillus actinomycetemcomitans despite clonal diversity.2008In: Journal of periodontology, ISSN 0022-3492, Vol. 79, no 2, p. 307-15Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Actinobacillus actinomycetemcomitans is a major pathogen in aggressive periodontitis. Our objectives were to determine the periodontal status and occurrence of A. actinomycetemcomitans in family members of subjects with A. actinomycetemcomitans-positive aggressive periodontitis (AgP) and to evaluate the probability of its intrafamilial transmission. METHODS: Of the 300 subjects screened, 66 (22%) had AgP and A. actinomycetemcomitans. Eleven (probands) of these 66 subjects with AgP met the strict inclusion criteria for the study. The study population consisted of 55 subjects, including probands and their family members (N = 44). Two family groups were formed according to whether the proband was a child (N = 7) or a parent (N = 4). Subgingival samples from all subjects were cultured for A. actinomycetemcomitans, and its clonal types were determined by combining serotype and genotype data for each isolate. RESULTS: Among 42 dentate family members, 16 (38%) exhibited periodontitis and eight (50%) had AgP. Periodontitis was found in nine of 12 (75%) of the dentate parents and six of 17 (35%) siblings of the child probands. A. actinomycetemcomitans was detected in 16 of 31 (52%) family members, i.e., one parent and at least one sibling in six families. The child probands shared A. actinomycetemcomitans clonal types with their parents in five of six (83%) families and with their siblings in three of six (50%) families. In the four parent-proband families, A. actinomycetemcomitans occurred in two spouses and all nine children. The parent probands shared A. actinomycetemcomitans clonal types with their spouses in both families and with their children in three of four families. In all families, the likelihood of intrafamilial transmission of A. actinomycetemcomitans was statistically significant. Members of most families (eight of 11, 73%) also harbored additional clonal types of A. actinomycetemcomitans. CONCLUSION: Parents and siblings of an individual with A. actinomycetemcomitans-positive AgP may have an increased susceptibility to periodontitis and shared and/or other clonal types of oral A. actinomycetemcomitans.

  • 97.
    Drobni, Mirva
    Umeå University, Faculty of Medicine, Odontology, Cariology.
    Adhesion-related interactions of Actinomyces and Streptococcus biofilm bacteria2006Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Adhesion of bacteria is a key event in biofilm formation and is mediated by bacterial adhesins recognising host or bacterial partner receptors. In oral biofilm formation, primary Actinomyces and Streptococcus colonizers adhere to salivary pellicle proteins such as proline-rich proteins (PRPs) as well as to mucosal surfaces. Subsequently, Actinomyces and Streptococcus strains and other bacteria, such as Veillonella, Fusobacterium and Porphyromonas, adhere to each other. The nature of this community is highly important for the health or disease status, although specific pathogenic species may also have been implicated.

    The aim of this thesis was to study key players in early oral colonisation, Actinomyces and Streptococcus species, and more specifically the nature of their adhesins and ligands. A further aim was to study the function of the salivary PRP proteins and an innate peptide derived thereof on bacterial adhesion, proliferation and regulation of pH, i.e. key factors in biofilm formation.

    In paper I and II, adhesion, proliferation and pH affecting features of the RGRPQ (arginine-glycine-arginine-proline-glutamine) peptide, derived from PRP-1, were demonstrated. By use of an alanine-scan (I), motifs for adhesion inhibition and desorption of Actinomyces naeslundii, and proliferation stimulation, ammonia production and inhibition of sucrose induced pH drop by Streptococcus gordonii were indicated. The RGRPQ peptide also stimulated S. gordonii colonisation in vivo. In paper II, a more sophisticated quantitative structure-activity relationship (QSAR) study, using statistical molecular design (SMD) and multivariate modelling (partial least squares projections to latent structures, PLS), further narrowed down the RGRPQ peptide motifs. The R and Q amino acids were crucial for activity. For proliferation a hydrophobic and large size third position amino acid was crucial, while adhesion inhibition and desorption needed a small hydrophilic second position amino acid. All functions depended on a low polarity hydrophobic fourth position. Accordingly, activities could be optimized separately, with decreased function in the others.

    In paper III and IV, focus was on the bacterial adhesins and their binding epitopes. The genes for FimA major subunit proteins of type-2 fimbriae were sequenced from A. naeslundii genospecies 1 and 2 and Actinomyces odontolyticus, each with unique carbohydrate binding specificities (III). Three major subtypes of FimA proteins were found that correlated with binding specificity, including a novel fimA gene in A. odontolyticus. All subtypes contained a pilin, LPXTG and E box motif. In paper IV, multiple PRP binding patterns for Actinomyces and Streptococcus strains were mapped using a hybrid peptide construct. The two most deviating binding groups deviated in type-1 fimbriae mediated binding to milk and saliva protein ligands.

    In conclusion, differences in bacterial adhesins and their ability to utilise salivary proteins may render bacteria tropism for different niches. Peptides derived from protein receptors, such as RGRPQ, may be important modulators of biofilm formation, giving commensal bacteria a competitive edge in the bacterial community.

  • 98.
    Drobni, Mirva
    et al.
    Umeå University, Faculty of Medicine, Odontology, Cariology.
    Hallberg, K
    Öhman, Ulla
    Umeå University, Faculty of Medicine, Odontology, Cariology.
    Birve, Anna
    Umeå University, Faculty of Medicine, Odontology, Cariology.
    Persson, Karina
    Umeå University, Faculty of Medicine, Odontology, Cariology.
    Johansson, Ingegerd
    Umeå University, Faculty of Medicine, Odontology, Cariology.
    Strömberg, Nicklas
    Umeå University, Faculty of Medicine, Odontology, Cariology.
    Sequence analyses of fimbriae subunit FimA proteins on Actinomyces naeslundii genospecies 1 and 2 and Actinomyces odontolyticus with variant carbohydrate binding specificities.2006In: BMC Microbiology, ISSN 1471-2180, E-ISSN 1471-2180, Vol. 43, no 6Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Actinomyces naeslundii genospecies 1 and 2 express type-2 fimbriae (FimA subunit polymers) with variant Galbeta binding specificities and Actinomyces odontolyticus a sialic acid specificity to colonize different oral surfaces. However, the fimbrial nature of the sialic acid binding property and sequence information about FimA proteins from multiple strains are lacking. RESULTS: Here we have sequenced fimA genes from strains of A.naeslundii genospecies 1 (n = 4) and genospecies 2 (n = 4), both of which harboured variant Galbeta-dependent hemagglutination (HA) types, and from A.odontolyticus PK984 with a sialic acid-dependent HA pattern. Three unique subtypes of FimA proteins with 63.8-66.4% sequence identity were present in strains of A. naeslundii genospecies 1 and 2 and A. odontolyticus. The generally high FimA sequence identity (> 97.2%) within a genospecies revealed species specific sequences or segments that coincided with binding specificity. All three FimA protein variants contained a signal peptide, pilin motif, E box, proline-rich segment and an LPXTG sorting motif among other conserved segments for secretion, assembly and sorting of fimbrial proteins. The highly conserved pilin, E box and LPXTG motifs are present in fimbriae proteins from other Gram-positive bacteria. Moreover, only strains of genospecies 1 were agglutinated with type-2 fimbriae antisera derived from A. naeslundii genospecies 1 strain 12104, emphasizing that the overall folding of FimA may generate different functionalities. Western blot analyses with FimA antisera revealed monomers and oligomers of FimA in whole cell protein extracts and a purified recombinant FimA preparation, indicating a sortase-independent oligomerization of FimA. CONCLUSION: The genus Actinomyces involves a diversity of unique FimA proteins with conserved pilin, E box and LPXTG motifs, depending on subspecies and associated binding specificity. In addition, a sortase independent oligomerization of FimA subunit proteins in solution was indicated.

  • 99.
    Drobni, Mirva
    et al.
    Umeå University, Faculty of Medicine, Odontology, Cariology.
    Li, Tong
    Kruger, C
    Loimaranta, V
    Kilian, M
    Hammarström, L
    Jörnvall, H
    Bergman, T
    Strömberg, Nicklas
    A host-derived pentapeptide affecting adhesion, proliferation and local pH in Streptococcus-Actinomyces biofilm communities.2006In: Infection and immunityArticle, review/survey (Other (popular science, discussion, etc.))
    Abstract [en]

    Salivary proline-rich proteins (PRPs) attach commensal Actinomyces and Streptococcus species to teeth. Here, gel filtration, mass spectrometry and Edman degradation were applied to show the release of a pentapeptide, RGRPQ, from PRP-1 upon proteolysis by Streptococcus gordonii. Moreover, synthetic RGRPQ and derivatives were used to investigate associated innate properties and responsible motifs. The RGRPQ peptide increased 2.5-fold the growth rate of S. gordonii via a Q-dependent sequence motif, and selectively stimulated oral colonization of this organism in a rat model in vivo. By contrast, growth of Streptococcus mutans, implicated in caries, was unaffected. While the entire RGRPQ sequence was required to block sucrose-induced pH-decrease by S. gordonii and S. mutans, the N-terminal Arg residue mediated pH-increase (i.e. ammonia production) by S. gordonii alone (which exhibits Arg catabolism to ammonia). Strains of commensal viridans streptococci exhibited PRP degradation and Arg catabolism, while cariogenic species did not. The RGRPQ peptide mediated via a differential Q-dependent sequence motif, adhesion inhibition and desorption of PRP-1-binding strains of A. naeslundii genospecies 2 (5 out of 10 strains) but not of S. gordonii (n=5). The inhibitable A. naeslundii strains alone displayed the same binding profile as S. gordonii to hybrid peptides terminating in RGRPQ or GQSPQ, derived from the middle or C-terminal segments of PRP-1. The present findings indicate the presence of a host-bacteria interaction where a host peptide released by bacterial proteolysis affects key properties in biofilm formation.

  • 100.
    Drobni, Mirva
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Cariology.
    Li, Tong
    Umeå University, Faculty of Medicine, Department of Odontology, Cariology.
    Krüger, Karina
    Loimaranta, Vuokko
    Umeå University, Faculty of Medicine, Department of Odontology, Cariology.
    Kilian, Mogens
    Hammarström, Lennart
    Jörnvall, Hans
    Bergman, Tomas
    Strömberg, Nicklas
    Umeå University, Faculty of Medicine, Department of Odontology, Cariology.
    A host-derived pentapeptide enhancing host-bacteria commensalisms and communication2006In: Infection and Immunity, ISSN 0019-9567, E-ISSN 1098-5522, Vol. 74, no 11, p. 6293-6299Article in journal (Refereed)
    Abstract [en]

    Salivary proline-rich proteins (PRPs) attach commensal Actinomyces and Streptococcus species to teeth. Here, gel filtration, mass spectrometry and Edman degradation were applied to show the release of a pentapeptide, RGRPQ, from PRP-1 upon proteolysis by Streptococcus gordond. Moreover, synthetic RGRPQ and derivatives were used to investigate associated innate properties and responsible motifs. The RGRPQ peptide increased 2.5-fold the growth rate of S. gordonii via a Q-dependent sequence motif and selectively stimulated oral colonization of this organism in a rat model in vivo. In contrast, the growth of Streptococcus mutans, implicated in caries, was not affected. While the entire RGRPQ sequence was required to block sucrose-induced pH-decrease by S. gordonii and S. mutans, the N-terminal Arg residue mediated the pH increase (i.e., ammonia production) by S. gordonii alone (which exhibits Arg catabolism to ammonia). Strains of commensal viridans streptococci exhibited PR-P degradation and Arg catabolism, whereas cariogenic species did not. The RGRPQ peptide mediated via a differential Q-dependent sequence motif, adhesion inhibition, and desorption of PRP-1-binding strains of A. naeslundii genospecies 2 (5 of 10 strains) but not of S. gordonii (n = 5). The inhibitable A. naeslundii strains alone displayed the same binding profile as S. gordond to hybrid peptides terminating in RGRPQ or GQSPQ, derived from the middle or C-terminal segments of PRP-1. The present findings indicate the presence of a host-bacterium interaction in which a host peptide released by bacterial proteolysis affects key properties in biofilm formation.

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