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  • 51.
    Al-Zuheri, Insam
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Tandläkarutbildning.
    Persson, Gina
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Tandläkarutbildning.
    The Effect of Topical Anesthesia on Jaw Pain Thresholds in Patients with Generalized Pain2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Chronic widespread pain and fibromyalgia often coexist with temporomandibular disorders (TMD) and affects mostly women. Studies have shown lower pressure pain thresholds (PPT) in these patients indicating that hyperalgesia is involved. The aim for this study was to investigate the effect of topical anesthesia on PPT for jaw muscles in patients with widespread pain. The hypothesis was that the PPT in these patients would increase after applying topical anesthetic cream. Ten women (aged 25-64 years, median: 50 years) diagnosed with TMD associated with widespread pain, reported from at least three different anatomical sites apart from the jaw region and pain to palpation according to the American College of Rheumatology criteria 1990, were included in the study. The double blind randomized trial was based on measurements of PPT with an Algometer before and after the application of anesthetic cream (EMLA) or placebo cream. The chosen measurement sites were the anterior part of the temporal muscle bilaterally, the belly of the masseter muscle bilaterally and the pollicis transversa muscle of the dominant hand. In the statistical analysis Wilcoxon’s rank sum test was used and a P-value <0.05 was considered statistically significant. There was a large inter-individual variation of PPT. No statistically significant differences in PPT-values before and after application of the EMLA or placebo creams were observed.

    In conclusion, the study showed that application of topical anesthesia had no significant effect on PPT in patients with widespread pain. Mechanisms related to central sensitization may have contributed to this result.

  • 52.
    Amin, Maha
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Asker, Firangiz
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Persistence and Detection of Bacterial DNA in a Root Canal Flora2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
  • 53. Anderson, M
    et al.
    Stecksén-Blicks, Christina
    Umeå universitet, Medicinsk fakultet, Odontologi, Pedodonti.
    Stenlund, Hans
    Umeå universitet, Medicinsk fakultet, Folkhälsa och klinisk medicin, Epidemiologi och folkhälsovetenskap.
    Ranggård, L
    Tsilingaridis, G
    Mejàre, I
    Detection of approximal caries in 5-year-old Swedish children2005Inngår i: Caries Research, Vol. 39, nr 2, s. 92-99Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim was to assess how accurately some commonly used risk factors/risk markers (predictors) for caries development could identify children with and without approximal caries as judged from bitewing radiography. 267 consecutive 5-year-old children from two Swedish cities participated. Three experienced dentists examined the children. The predictors were the overall dmfs value (canines and molars), the number of occlusal dmfs, the frequency of intake of between meal sugary products, visible plaque on free smooth surfaces of second primary molars, toothbrushing habits, and (before bitewing examination) an overall judgement by the examining dentist. The mean dmfs without bitewing examination (BW) was 0.40 (SD = 1.22). Twelve percent of the children had at least one dentin lesion and 33 % at least one enamel lesion that were detected from BW only. The gain from adding BW to clinical examination amounted to a mean of 1.2 approximal enamel and/or dentin lesions. Results: The ability to correctly identify children with approximal caries from the predictors was limited; sensitivity ranged from 0.27 to 0.75 and specificity ranged from 0.41 to 0.93. The single best predictor was the dentist's overall judgement with an average precision of 73 %; average sensitivity for the presence of enamel and dentin lesions was 0.48 and for the presence of dentin lesions 0.66. The rest of the predictors added little to the predictive power. It is concluded that 33 % of the 5-year-olds, representing a low caries prevalence population, benefited from BW. The ability to identify these children from the predictors was, however, limited.

  • 54. Andersson, A
    et al.
    Sköld-Larsson, K
    Hallgren, A
    Pettersson, LG
    Twetman, Svante
    Umeå universitet, Medicinsk fakultet, Odontologi.
    White spot lesion regression with the CPP-ACP system assessed by a laser fluorescence device (DIAGNOdent).2006Inngår i: Oral Health Prev DentArtikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose: To investigate and compare the effects of a dental cream containing complexes of casein phosphoprotein-amorphous calcium phosphate (CPP-ACP) and fluoride mouth rinses on the regression of white spot lesions (WSL). Material and methods: The study group consisted of 26 healthy adolescents (mean age 14.6 yr) exhibiting 60 teeth with 152 visible WSL sites on incisors and canines immediately after debonding of fixed orthodontic appliances. After bracket removal, professional tooth cleaning and drying, a visual scoring (0-4) and laser fluorescence (LF) readings were carried out. The patients were randomly assigned to two different treatment protocols with the aim to remineralize the lesions: A) daily topical applications of a dental cream containing CPP-ACP (Topacal) for 3 months followed by a 3-month period of daily tooth brushing with fluoridated toothpaste, or B) daily 0.05% sodium fluoride rinses combined with fluoridated toothpaste for 6 months. The registrations were repeated after 1, 3, 6 and 12 months and follow-up data were compared with baseline with aid of chi-square and paired t-tests. Results: A significant improvement of the clinical WSL-scores was found over time in both groups but there was a statistically significant difference (p<0.01) concerning the number of sites that totally disappeared after 12 months in favor for the CPP-ACP regime, 63% vs. 25% respectively. The clinical registrations were mirrored by a statistically significant decrease (p<0.05) in the LF readings at the 6- and 12-month follow-ups compared to baseline. No significant differences were displayed between the groups. Conclusion: Clinical scoring and LF assessment suggested that both regimens could promote regression of WSL after debonding of fixed orthodontic appliances. The visual evaluation suggested an aesthetically more favourable outcome of the amorphous calcium phosphate treatments.

  • 55. Andersson, MK
    et al.
    Lundberg, Pernilla
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Ohlin, A
    Perry, MJ
    Lie, Anita
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Stark, A
    Lerner, Ulf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Effects on osteoclast and osteoblast activities in cultured mouse calvarial bones by synovial fluids from patients with a loose joint prosthesis and from osteoarthritis patients.2007Inngår i: Arthritis Research & Therapy, ISSN 1478-6354, E-ISSN 1478-6362, Vol. 9, nr 1, s. R18-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aseptic loosening of a joint prosthesis is associated with remodelling of bone tissue in the vicinity of the prosthesis. In the present study, we investigated the effects of synovial fluid (SF) from patients with a loose prosthetic component and periprosthetic osteolysis on osteoclast and osteoblast activities in vitro and made comparisons with the effects of SF from patients with osteoarthritis (OA). Bone resorption was assessed by the release of calcium 45 (45Ca) from cultured calvariae. The mRNA expression in calvarial bones of molecules known to be involved in osteoclast and osteoblast differentiation was assessed using semi-quantitative reverse transcription-polymerase chain reaction (PCR) and real-time PCR. SFs from patients with a loose joint prosthesis and patients with OA, but not SFs from healthy subjects, significantly enhanced 45Ca release, effects associated with increased mRNA expression of calcitonin receptor and tartrate-resistant acid phosphatase. The mRNA expression of receptor activator of nuclear factor-kappa-B ligand (rankl) and osteoprotegerin (opg) was enhanced by SFs from both patient categories. The mRNA expressions of nfat2 (nuclear factor of activated T cells 2) and oscar (osteoclast-associated receptor) were enhanced only by SFs from patients with OA, whereas the mRNA expressions of dap12 (DNAX-activating protein 12) and fcrgamma (Fc receptor common gamma subunit) were not affected by either of the two SF types. Bone resorption induced by SFs was inhibited by addition of OPG. Antibodies neutralising interleukin (IL)-1alpha, IL-1beta, soluble IL-6 receptor, IL-17, or tumour necrosis factor-alpha, when added to individual SFs, only occasionally decreased the bone-resorbing activity. The mRNA expression of alkaline phosphatase and osteocalcin was increased by SFs from patients with OA, whereas only osteocalcin mRNA was increased by SFs from patients with a loose prosthesis. Our findings demonstrate the presence of a factor (or factors) stimulating both osteoclast and osteoblast activities in SFs from patients with a loose joint prosthesis and periprosthetic osteolysis as well as in SFs from patients with OA. SF-induced bone resorption was dependent on activation of the RANKL/RANK/OPG pathway. The bone-resorbing activity could not be attributed solely to any of the known pro-inflammatory cytokines, well known to stimulate bone resorption, or to RANKL or prostaglandin E2 in SFs. The data indicate that SFs from patients with a loose prosthesis or with OA stimulate bone resorption and that SFs from patients with OA are more prone to enhance bone formation.

  • 56.
    Andersson, Ronja
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Amiri, Hero
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Influence of Colour of Cement, Ceramic Thickness and Try-in pastes on the Colour of Ceramic Restorations. Mapping of the Literature2016Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Today it is possible to create veneers that are aesthetically and functionally satisfying, but there are some factors that may compromise the aesthetic results.  The aim of this study was to investigate influence of cement shades and ceramic thickness on the colour of ceramic veneers, but also to study how well try-in pastes match with their corresponding cements.

    PubMed was used to search for papers using MeSH-terms and keywords. 144 titles and abstracts were read, 29 full texts were read and 24 papers were used in the analysis. All of the studies were in vitro.

    In 20 studies, it was found that the cement shade influences the colour of the ceramic veneer. Two studies reported that the cement shade had no influence on the colour of ceramic veneers, and two did not draw any conclusions regarding the influence of cement shade. Twelve studies compared different thicknesses of the veneers; all of them found that the thicknesses had an influence on the colour of the veneers.

    Two out of four studies found no compatibility between try-in pastes and their corresponding cements, while two studies found compatibility for some try-in pastes.

    The shades of cement and thicknesses of ceramic veneers can influence the colour of the ceramics. The colour of try-in pastes does not always show a similarity with their corresponding cement.

  • 57.
    Andersson, Samuel
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Öst, Martin
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Two Ways of Starting Titration with an Oral Appliance for Obstructive Sleep Apnea2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
  • 58.
    Andersson, Sanna
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Goodwin, Sofie
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Effect of electric biofeedback on sleep-related bruxism2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
  • 59.
    Andersson-Gran, Elin
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Jensen, Eric
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Fixed Prosthesis with Limited Implant Support A. Pilot study of the All-on-2 Concept.2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
  • 60.
    Andersson-Wenckert, Ingrid
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Pedodonti.
    Sunnegårdh-Grönberg, Karin
    Umeå universitet, Medicinsk fakultet, Odontologi, Kariologi.
    Flowable resin composite as a class II restorative in primary molars: A two-year clinical evaluation.2006Inngår i: Acta Odontologica Scandinavica, ISSN 0001-6357, E-ISSN 1502-3850, Vol. 64, nr 6, s. 334-340Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    OBJECTIVE: To evaluate the clinical durability of flowable resin composite and resin-modified glass ionomer cement when used as class II restoratives in primary molars. MATERIAL AND METHODS: A total of 190 restorations were placed in 61 children, age in the range of 5-11 years. The restoratives, Tetric Flow, in combination with the adhesives, Excite or Prompt-L-Pop and Vitremer, were used in class II cavities in primary molars. An intra-individual study design was used and the restorations were evaluated by modified USPHS criteria over a 2-year period. RESULTS: 146 of the restorations could be evaluated at 2 years. The cumulative failure rate was 10.6% for Vitremer and 13.6% for Tetric Flow. No statistically significant differences were found in failure rates between different materials or between bonding systems. The main cause of failure for Tetric Flow was secondary caries and for Vitremer wear and dissolution. CONCLUSIONS: Vitremer and Tetric Flow showed no significant difference concerning clinical durability at 2 years when used as class II restoratives in primary molars. Both materials demonstrated acceptable clinical results.

  • 61.
    Andersson-Wenckert, Ingrid
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Pedodonti.
    van Dijken, Jan
    Umeå universitet, Medicinsk fakultet, Odontologi, Tandhygienistprogrammet.
    Kieri, C
    Durability of extensive Class II open-sandwich restorations with a resin-modified glass ionomer cement after 6 years.2004Inngår i: American Journal of Dentistry, ISSN 0894-8275, Vol. 17, nr 1, s. 43-50Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    PURPOSE: To evaluate the durability of a modified open-sandwich restoration utilizing a resin-modified glass ionomer cement (RMGIC) in large cavities. METHODS: 268, mostly extensive, Class II Vitremer/Z100 restorations were placed in 151 patients. 47% of the restorations were placed in patients considered as caries-risk patients. Six experimental groups, differing from each other in thickness of RMGIC layer and preconditioning, were evaluated at baseline and annually during 6-7 years according to modified USPHS criteria. RESULTS: After 6 years, 220 restorations were evaluated. 42 failures (19%) were observed. The most frequent reasons for failure were material fracture (n = 11), tooth fractures (n = 9) and secondary caries (n = 10). Non-acceptable proximal dissolution of the RMGIC was seen in six restorations. Significantly more failures, but similar dissolution of the RMGIC, were recorded in high caries risk patients. No differences were seen between the experimental groups or between restorations with thick or thin RMGIC layer. 160 restorations were also evaluated at 7 years. Another 13 failures were observed, eight with non-acceptable dissolution, three secondary caries and two fractures. It can be concluded that the modified open sandwich restoration showed an acceptable durability for the extensive restorations evaluated. An accelerating dissolution of the RMGIC was observed at the end of the study.

  • 62. Andrup, Max
    et al.
    Elenius, Jesper
    Ramirez, Eusebio
    Sjöström, Mats
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Indications and Frequency of Orthognathic Surgery in Sweden – A Questionnaire Survey2015Annet (Fagfellevurdert)
    Abstract [en]

    Orthognathic surgery, a standard procedure used to improve intermaxillary relationship, surgically moves either one or both jaws. However, statistics for frequency and indications for orthognathic surgery in Sweden are non-existent. This study examines indications, frequency, and surgical techniques for orthognathic surgery performed in Oral and Maxillofacial Surgery (OMFS) clinics in Sweden. In 2011, a questionnaire survey was sent to all OMFS clinics in Sweden to collect data on gender and age of patients, surgical techniques, indications, frequency of operations, and whether patients underwent one- or two-jaw surgery. Of the 50 OMFS clinics, 47 responded, revealing that 891 patients in 23 clinics were treated with orthognathic surgery, slightly more women than men were treated, and 91% of the patients were 26 years or younger. The results from our survey indicate that functional indication is the most common surgical indication. This is not in line with the literature, which describes the aesthetic component as the most common indication. One explanation could be that the treatment in Sweden is heavily subsidized by federal financial support if certain inclusions criteria are fulfilled. These criteria are mainly based on cephalometric analysis together with dental arch relationship and not on aesthetic components, which are harder to measure. It was also revealed that there was a great discrepancy among the Swedish counties concerning one- vs. two-jaw surgery. A possible reason for this can be differences in surgical experience and custom at each OMFS clinic.

  • 63.
    André, Maria
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Kou, Wen
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Sjögren, Göran
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Sundh, Anders
    Research and Development, Cad.esthetics AB, Skellefteå, Sweden.
    Effects of pretreatments and hydrothermal aging on biaxial flexural strength of lithium di-silicate and Mg-PSZ ceramics2016Inngår i: Journal of Dentistry, ISSN 0300-5712, E-ISSN 1879-176X, Vol. 55, s. 25-32Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Objectives: To evaluate the effect of specimen thickness, pretreatment and hydrothermal aging on the biaxial flexural strength (BFS) of lithium di-silicate glass (e.max Cad) and magnesia-stabilized zirconia (ZirMagnum) ceramic discs. Methods: The e.max Cad discs was studied: i) crystallized, ii) crystallized and glazed and iii) crystallized, glazed and unglazed side etched with hydrofluoric acid. The ZirMagnum discs were studied: i) as delivered, ii) after sandblasting and iii) after heat treatment similar to veneering. Hydrothermal aging was simulated by autoclave treatment. Results: The BFS of all the ZirMagnum specimens was superior (p < 0.001) to all the e.max Cad specimens. Glazing the 0.4 mm e.max Cad discs reduced (p < 0.05) their BFS compared with the unglazed 0.8 mm specimens, whereas glazing of 0.8 mm discs had no influence (p > 0.05) on the strength. Etching and autoclaving of e.max Cad did not affect (p > 0.05) the BFS. For ZirMagnum sandblasting with 0.2 MPa or 0.6 MPa did not influence the biaxial flexural strength (p > 0.05), whereas heat treatment reduced (p < 0.01) the BFS of 0.6 MPa sandblasted ZirMagnum. Autoclaving reduced the strength (p < 0.05) compared with ZirMagnum as delivered, whereas autoclaving of the 0.6 MPa sandblasted and heat treated specimens did not influence (p > 0.05) the BFS. Glazing, etching and sandblasting increased (p < 0.05) surface roughness. Conclusions: The effects of glazing, heat treatment, aging and mechanical treatment of the materials evaluated should be considered since their strength could be affected. Clinical significance: Mechanical properties of restorations made from prefabricated ceramic blocks could be affected of various treatments and could change over time.

  • 64. Anwer, Shahnawaz
    et al.
    Alghadir, Ahmad
    Zafar, Hamayun
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi. Department of Rehabilitation Sciences, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia.
    Al-Eisa, Einas
    Effect of whole body vibration training on quadriceps muscle strength in individuals with knee osteoarthritis: a systematic review and meta-analysis2016Inngår i: Physiotherapy, ISSN 0031-9406, E-ISSN 1873-1465, Vol. 102, nr 2, s. 145-151Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Background Several studies have reported the effects of whole body vibration (WBV) training on muscle strength. This systematic review investigates the current evidence regarding the effects of WBV training on quadriceps muscle strength in individuals with knee osteoarthritis (OA). Data sources We searched PubMed, CINAHL, Embase, Scopus, PEDro, and Science citation index for research articles published prior to March 2015 using the keywords whole body vibration, vibration training, strength and vibratory exercise in combination with the Medical Subject Heading 'Osteoarthritis knee'. Study selection This meta-analysis was limited to randomized controlled trials published in the English language. Data extraction The quality of the selected studies was assessed by two independent evaluators using the PEDro scale and criteria given by the International Society of Musculoskeletal and Neuronal Interactions (ISMNI) for reporting WBV intervention studies. The risk of bias was assessed using the Cochrane collaboration's tool for domain-based evaluation. Isokinetic quadriceps muscle strength was calculated for each intervention. Results Eighteen studies were identified in the search. Of these, four studies met the inclusion criteria. Three of these four studies reached high methodological quality on the PEDro scale. Out of the four studies, only one study found significantly greater quadriceps muscle strength gains following WBV compared to the control group. Conclusions In three of the four studies that compared a control group performing the same exercise as the WBV groups, no additional effect of WBV on quadriceps muscle strength in individuals with knee OA was indicated.

  • 65.
    Ardlin, Berit
    Umeå universitet, Medicinsk fakultet, Odontologi.
    Transformation-toughened zirconia for dental inlays, crowns and bridges:: chemical stability and effect of low-temperature aging on flexural strength and surface structure2002Inngår i: Dental Materials: Journal for Oral and Craniofacial Biomaterials Sciences, ISSN 0109-5641, Vol. 18, nr 8, s. 590-5Artikkel i tidsskrift (Fagfellevurdert)
  • 66.
    Ardlin, Berit
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi.
    Dahl, Jon E
    Tibballs, John E
    Static immersion and irritation tests of dental metal-ceramic alloys2005Inngår i: European Journal of Oral Sciences, ISSN 0909-8836, Vol. 113, nr 1, s. 83-9Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The expansion of the European Union is bringing new types of metal-ceramic alloys to the market, i.e. alloys probably unknown in Western-European dentistry. The aim of this study was to investigate recent developments and "classic" alloy compositions (one iron and two cobalt alloys, unalloyed titanium and an experimental titanium-zirconium alloy, and one gold alloy containing copper and zinc). The alloys and titanium were subject to static immersion in a 0.1 mol l(-1) solution of saline lactic acid before and after oxidation, hence simulating the temperature cycles for the application of ceramic to metal. The greatest amounts of released metal ions were found in the electrolytes of the oxidized gold alloy and of a cobalt alloy not exposed to high-temperature oxidation. Corrosion of the titanium and alloy surfaces was related to the condition of the specimen. The irritation potentials of some metal ions found in the electrolyte were investigated by performing the hen's egg test-chorio-allantoic membrane (HET-CAM) procedure with 1 mmol l(-1) solutions of Ce(3+), Co(2+), Cu(2+), Zn(2+), Fe(2+), and Ti(4+) ions. The irritation potential of the electrolyte of the oxidized gold alloy with a high concentration of metal elements was also investigated. Of these solutions, only the 1 mmol l(-1) Cu(2+) solution was graded as slightly irritating.

  • 67.
    Ardlin, Berit I
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi.
    Lindholm-Sethson, Britta
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Kemi.
    Dahl, Jon E
    Corrosion of dental nickel-aluminum bronze with a minor gold content-mechanism and biological impact.2009Inngår i: Journal of Biomedical Materials Research Part B: Applied Biomaterials, ISSN 1552-4981, Vol. 88B, nr 2, s. 465-73Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Objectives: To study corrosion and to evaluate biological effects in vitro of corrosion products of a copper-aluminum-nickel alloy with 2% gold. Methods: The alloy NPGTM+2 with the nominal composition Cu:77.3; Al:7.8; Ni:4.3; Fe:3.0; Zn:2.7; Au:2.0; and Mn:1.7 was characterized. Static immersion in acidic saline, pH 2.2-2.4, was used to determine release of metallic elements in a milieu simulating the condition of plaque build-up in interproximal areas of the tooth. Corrosion and surface reactions in saline and artificial saliva were studied by electrochemical techniques including registration of open-circuit-potentials, polarization curves and impedance spectra. Extracts were made in cell culture media and acidic saline and used for MTT test for cytotoxicity and HET-CAM method for irritation. Results: The mean amount of elements released in the acidic saline were in g cm-2 : Cu:632; Al:210; Ni:144; Fe:122; Zn:48; Mn:52. No protective film was formed on the surface of the alloy, as extensive corrosion was observed in both saline and artificial saliva. The corrosion rate was higher in saline than in artificial saliva. Acidic extracts of the alloy diluted up to 64 times reduced cell viability with 80% or more. The extract induced coagulation of the blood vessels of the CAM and was rated as moderate irritant solution. Significance: The nickel-aluminum bronze showed high corrosion rate caused by an inability to create a protective surface layer. High levels of toxic elements were found after static immersion testing, and the corrosion products had a distinct adverse effect on the biological activity.

  • 68.
    Ardlin, Berit
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Odontologisk materialvetenskap.
    Lindholm-Sethson, Britta
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Kemi.
    Effects of pH and Fluorides on Titanium2005Inngår i: Society for Biomaterials, 30th Annual Meeting & Exposition, Memphis,TN, USA: New Applications and Technologies, 2005Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Introduction: Titanium is used in dentistry both for crowns, fixed and removable partial dentures, suprastructures and for implants. In such applications, titanium may come in contact with fluorides. Prophylactic agents such as toothpastes and gels have effects on titanium that are dependent on their acidity and fluoride concentration. In order to obtain rapid bone growth and a strong bond between the implant and the bone, fluorides are used to modify the surfaces of titanium implants1. The aim of this investigation was to study the release of ions and the effects of fluorides on surfaces of titanium cp-II in saline solutions of different pF and pH using a) a brush test and b) electrochemical techniques including impedance spectroscopy2.

    Materials and Methods: Brush test. An electric toothbrush was used to brush the titanium electrodes for 2 min in aqua solutions of 0.9 % NaCl with 0, 0.3, 0.6 and 1 % NaF. The pH of the solutions was adjusted by adding ultra pure HNO3 and 1 M NaOH. In order to avoid interference with the chemical analyses, the solutions were not buffered. The solutions were divided into two all-embracing groups, pH 4.5 and pH>5.3, with respect to their acidity. An atomic absorption spectrophotometer equipped with a graphite atomizer with Zeeman effect background correction was used to detect titanium in the NaCl solutions.

    Electrochemical tests. Planar titanium electrodes with surface area of 0.28 cm2 served as working electrodes and were wet-ground with SiC paper through 1200 grit using standard metallographic procedures prior to exposure to the various electrolyte solutions. The solutions employed were similar to those used in the previous experiments, i.e. phosphate-buffered 0.9 % NaCl solutions with a pH between 4 and 7, containing 0, 0.3, 0.6 and 1 % NaF. An ordinary three-electrode setup was used with Ag/AgCl, sat KCl as a reference electrode and a platinum sheet as a counter electrode. The open circuit potential was recorded for 18–20 hours, and the electrode was then polarized to –0.18 V vs. ref. for five minutes. After this an impedance spectrum was recorded at –0.18 V vs. ref in the frequency range 100 000 Hz to 5 mHz and an amplitude of 10 mV peak to peak. Finally a linear anodic polarization curve was recorded from –0.5 V to 1 V vs ref at a sweep rate of 2 mV/sec.

    Results: The result of the brush tests is shown in Table 1. The highest amount of titanium was detected in the NaCl solutions with 0.6 or 1.0 % NaF at pH 4.5.

    Titanium remains passive in neutral solutions irrespective of the addition of fluoride and also at pH 4 without addition of fluoride. This is indicated in all three electrochemical experiments: the final electrode potential at open circuit is around -0.1 V vs ref after 18 hours, the impedance spectrum shows an almost pure capacitive behavior and the current at anodic polarization is very small. At low pH with addition of fluoride, titanium becomes active, as evidenced by a negative final electrode potential at open circuit of around -1.0 V vs ref after 18 hours, an impedance spectrum indicating a non-blocking electrode and a high current at anodic polarization. At medium pH and with an addition of fluoride the electrochemical experiments indicate the formation of a porous non-passivating surface film. In the latter case the final open circuit potential is around -0,5 V vs ref, the impedance spectra show a non-blocking electrode with a large charge-storing capacity and the current at anodic polarization is close to the values obtained for the active electrode at pH 4. The results of the electrochemical tests are summarized in Table 2

  • 69.
    Ardlin, Berit
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi.
    Lindholm-Sethson, Britta
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Kemi.
    Dahl, Jon E.
    Corrosion and Irritation Tests of a Dental Aluminum Bronze2006Inngår i: International Association for Dental Research, 84th General Session & Exhibition, Brisbane, Australia, 2006Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Corrosion and irritation tests of a dental aluminium bronze. B.I. ARDLIN*1,2, B. LINDHOLM-SETHSON1 and J.E. DAHL2, 1Umeå University, Sweden, 2NIOM – Nordic Institute of Dental Materials, Haslum, Norway

    Objectives: The aims of this investigation were to study the corrosion of a copper-aluminium-nickel alloy for fixed prostheses, and to evaluate possible irritant effects of the corrosion products.

    Methods: The alloy NPG+2 with the nominal composition Cu:77.3; Al:7.8; Ni:4.3; Fe:3.0; Zn:2.7; Au:2.0; Mn:1.7, was characterized. Static immersion in saline lactic acid solution was selected to quantify metallic elements released in a milieu simulating the condition of plaque build-up in interproximal areas. Corrosion and surface reactions in artificial saliva and saline solutions were studied by electrochemical techniques including registration of polarization curves and impedance spectra. Irritative effect of the corrosion products was assed by the Hen’s egg test-chorio-allantoic membrane, HET-CAM.

    Results: Immersion test. The following metal elements were found in the saline lactic acid solutions after immersion of two specimens for 7 days (specimen 1 / specimen 2 in g cm-2): Cu (769/494); Al (249/172); Ni (164/124), Fe (134/109); Zn (59/37); and Mn (61/43). Electrochemical tests. Higher corrosion rates were found in the saline solution, pH 4 or pH 7, than in the aerated or de-aerated artificial saliva solution. No high-quality passive film was formed on the studied alloy as extensive corrosion was observed on test specimens in both solutions. HET CAM. The saline lactic acid extracts induced coagulation of the blood vessels of the chorio-allantoic membrane after an average time of 1 min and the alloy was rated as a moderate irritant.

    Conclusions: The copper-aluminium-nickel alloy investigated in this study showed high corrosion caused by an inability to create a stable passivating surface layer. High levels of the elements Cu, Al, Ni, Fe, Zn and Mn were found by static immersion testing, and the corrosion products had an irritant effect.

    The project was supported by grants from the European Union Structure Foundation Objective One.

  • 70.
    Asad, Lanna
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Tandläkarutbildning.
    Jumaa, Hifi
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Tandläkarutbildning.
    The Significance of Person-Centered Information on Dental Anxiety – a mixed method study2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Dental anxieties are one of the most common forms of anxieties today and represent an obstacle for both the patients and the therapists. The aim of this study was twofold; first, to describe experiences of and assess dental anxiety among patients, and second, based on this develop, implement and evaluate a person-centered information program to decrease experiences of dental anxiety. Our hypothesis was that person-centered information reduces dental anxiety estimated by the Dental Anxiety Scale (DAS). The higher initially measured anxiety the greater reduction of anxiety at the final measurement. This is a descriptive intervention study with a mixed method design based on individual interviews and questionnaires about dental anxiety. Eight patients, median age 51.50 + Q1=35.00, Q3=67.00 completed the program. Dental Anxiety Scale was used to measure the level of dental anxiety and to evaluate the effect of person-centered information. The analysis of the interviews resulted in three content areas: causes of dental anxiety, expressions of dental anxiety and preference of information. Pre-intervention median DAS was 13.50 + Q1=12.25, Q3=16.50. In seven of the participants the score of the dental anxiety decreased and one did not change in scores on DAS. The post-intervention median DAS was 9.50 + Q1=8.25, Q3=12.75, with a statistically significant change (p<0.05). In conclusion, the hypothesis was supported. Person-centered information based on the history of dental anxiety and the participants’ preferences, may be helpful in reducing dental anxiety.

  • 71.
    Asikainen, Sirkka
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Doğan, Başak
    Department of Periodontology, Faculty of Dentistry, Marmara University, Istanbul, Turkey.
    Turgut, Zeynep
    Department of Periodontology, Gazi University, Ankara, Turkey.
    Paster, Bruce J
    Department of Molecular Genetics, The Forsyth Institute, Boston, Massachusetts, United States of America.
    Bodur, Aysen
    Department of Periodontology, Gazi University, Ankara, Turkey.
    Oscarsson, Jan
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Specified species in gingival crevicular fluid predict bacterial diversity2010Inngår i: PloS one, ISSN 1932-6203, Vol. 5, nr 10, s. e13589-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Among a variety of detected species those traditionally classified as Gram-negative anaerobes growing in mature subgingival biofilms were the main predictors for species diversity in GCF samples as well as responsible for distinguishing GCF samples from PP samples. GCF bacteria may provide new prospects for studying dynamic properties of subgingival biofilms.

  • 72.
    Asikainen, Sirkka E
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Periodontal bacteria and cardiovascular problems.2009Inngår i: Future microbiology, ISSN 1746-0921, Vol. 4, s. 495-498Artikkel i tidsskrift (Annet vitenskapelig)
  • 73.
    Asikainen, Sirkka
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi.
    Karched, Maribasappa
    Umeå universitet, Medicinsk fakultet, Odontologi.
    Molecular techniques in oral microbial taxonomy, identification and typing2008Inngår i: Molecular Oral Microbiology, Caister Academic Press, Norfolk UK , 2008, s. 1-27Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    The rapid development of molecular techniques during the past decade has revolutionized the field of microbiology. Two issues are of profound importance. First, the discovery of phylogenetically informative DNA sequences, such as the 16S rRNA gene, radically changed the concept of bacterial relatedness and provided a universal system for bacterial identification and categorization. Second, it became possible to detect, identify, and type bacteria independent of their cultivability and, by these new means, to elucidate the diversity and spatial organization of complex oral bacterial communities. Of considerable benefit has been the fact that the same nucleic acid-based molecular approaches can be applied in all microbial environments, ranging from the oral cavity, to the surfaces of historical monuments, to the depths of open oceans. This has led to development of versatile PCR- and hybridization-based techniques that allow a rapid and convenient analysis of the bacterial contents of oral samples and offer previously unattainable possibilities for expanding studies on bacterial epidemiology and characterization. In particular, the emerging new microarray technology will facilitate great strides in understanding the structure and dynamics of oral bacterial communities and bacteria-host interactions, and will form the basis for developing novel diagnostics for oral infections.

  • 74.
    Aspholm, Marina
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Adaptation of Helicobacter pylori Adherence Properties in Promotion of Host Tropism and Inflammatory Disease2004Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Being among the most prevalent of persistent infectious agents in humans worldwide, Helicobacter pylori induces chronic inflammation (gastritis), which may progress to peptic ulceration and stomach cancer. The ability to adhere to the gastric mucosa is considered to be both a colonization and virulence property of H. pylori. For adherence, H. pylori expresses surface-located attachment proteins (adhesins) that bind to specific receptors in the gastric mucosa. The best characterized H. pylori adhesin-receptor interaction is that between the blood group antigen binding adhesin (BabA) and the fucosylated blood group antigens, which are glycans highly expressed in the gastric mucosa.

    Our recent results have changed the view of the blood group antigen-specific binding mode of H. pylori. We have tested clinical isolates of H. pylori from human populations worldwide for their ability to bind to ABO blood group antigens. The results revealed that more than 95% of isolates from Sweden, Germany, Spain, Japan and Alaska that bind fucosylated blood group antigens, bind both the Lewis b antigen (Leb) (of blood group O) and the blood group A-related antigen A-Lewis b, i.e. they exhibit a generalist type of binding mode. In contrast, the majority of strains (62%) from South American Amerindians bound best to Leb, i.e. they exhibit a specialist blood group “O antigen” binding mode. This specialization in binding coincides with the unique predominance of blood group O in the South American Amerindian populations. Furthermore, we also showed that H. pylori could switch from specialist to generalist binding modes by chromosomal integration of foreign babA gene fragments.

    A mutant strain lacking the babA gene turned out to adhere to inflamed gastric epithelium, despite the fact that it did not bind Leb. We identified the receptor to which the mutant binds to as the sialyl-dimeric-Lewis x antigen (sdiLex) and found its expression to be associated with persistent H. pylori infection and chronic inflammation, both in humans and Rhesus monkeys. The cognate sialic acid binding adhesin (SabA) was identified by our ReTagging technique. Deletion of sabA caused loss of H. pylori binding to sialylated glycans, and screening of single colony isolates revealed a high frequency of spontaneous on⇒off phase variation in sLex binding.

    Using erythrocytes as a model for sialyl dependent cell adhesion, we could show that SabA is the sought-after H. pylori sialyl-dependent hemagglutinin. Swedish clinical H. pylori isolates were analyzed for sialyl-dependent hemagglutination (sia-HA), and the sia-HA titers were found to be highly correlated to the levels of sLex binding. Clinical isolates were shown to exhibit several distinct binding modes for sialylated glycans, which suggest that SabA exhibit polymorphism in binding. We also found that SabA binds to sialylated glycans on neutrophil surfaces by mechanisms involving “selectin mimicry”, and that SabA plays an important role in nonopsonic activation of neutrophils.

    In the human stomach, H. pylori is exposed to selective pressures such as immune and inflammatory responses, and this is reflected by changes in mucosal glycosylation patterns. The high mutation and recombination rates of H. pylori in combination with bio selection will continuously generate clones that are adapted to changes in individual gastric mucosa. Such adaptive selection contributes to the remarkable diversity in binding modes and to the extraordinary chronicity of H. pylori infections worldwide.

  • 75.
    Aspholm-Hurtig, M
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Olfat, FO
    Sondén, B
    Altraja, S
    Wadström, T
    Engstrand, L
    Teneberg, S
    Borén, Thomas
    The Helicobacter pylori SabA Adhesin Exhibits Polymorphism in Binding and is the Same as the Sialic Acid Specific HemagglutininManuskript (preprint) (Annet (populærvitenskap, debatt, mm))
  • 76.
    Aspholm-Hurtig, Marina
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Dailide, Giedrius
    Lahmann, Martina
    Kalia, Awdhesh
    Ilver, Dag
    Roche, Niamh
    Vikström, Susanne
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Sjöström, Rolf
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi. Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik.
    Lindén, Sara
    Bäckström, Anna
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Lundberg, Carina
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Arnqvist, Anna
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi. Umeå universitet, Medicinska fakulteten, Molekylärbiologi (Teknat- och Medfak). Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik.
    Mahdavi, Jafar
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Nilsson, Ulf J
    Velapatiño, Billie
    Gilman, Robert H
    Gerhard, Markus
    Alarcon, Teresa
    López-Brea, Manuel
    Nakazawa, Teruko
    Fox, James G
    Correa, Pelayo
    Dominguez-Bello, Maria Gloria
    Perez-Perez, Guillermo I
    Blaser, Martin J
    Normark, Staffan
    Carlstedt, Ingemar
    Oscarson, Stefan
    Teneberg, Susann
    Berg, Douglas E
    Borén, Thomas
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik. Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Functional adaptation of BabA, the H. pylori ABO blood group antigen binding adhesin.2004Inngår i: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 305, nr 5683, s. 519-522Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Adherence by Helicobacter pylori increases the risk of gastric disease. Here, we report that more than 95% of strains that bind fucosylated blood group antigen bind A, B, and O antigens (generalists), whereas 60% of adherent South American Amerindian strains bind blood group O antigens best (specialists). This specialization coincides with the unique predominance of blood group O in these Amerindians. Strains differed about 1500-fold in binding affinities, and diversifying selection was evident in babA sequences. We propose that cycles of selection for increased and decreased bacterial adherence contribute to babA diversity and that these cycles have led to gradual replacement of generalist binding by specialist binding in blood group O-dominant human populations.

  • 77. Assi, Nada
    et al.
    Moskal, Aurelie
    Slimani, Nadia
    Viallon, Vivian
    Chajes, Veronique
    Freisling, Heinz
    Monni, Stefano
    Knueppel, Sven
    Foerster, Jana
    Weiderpass, Elisabete
    Lujan-Barroso, Leila
    Amiano, Pilar
    Ardanaz, Eva
    Molina-Montes, Esther
    Salmeron, Diego
    Ramon Quiros, Jose
    Olsen, Anja
    Tjonneland, Anne
    Dahm, Christina C.
    Overvad, Kim
    Dossus, Laure
    Fournier, Agnes
    Baglietto, Laura
    Fortner, Renee Turzanski
    Kaaks, Rudolf
    Trichopoulou, Antonia
    Bamia, Christina
    Orfanos, Philippos
    De Magistris, Maria Santucci
    Masala, Giovanna
    Agnoli, Claudia
    Ricceri, Fulvio
    Tumino, Rosario
    de Mesquita, H. Bas Bueno
    Bakker, Marije F.
    Peeters, Petra H. M.
    Skeie, Guri
    Braaten, Tonje
    Winkvist, Anna
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Näringsforskning.
    Johansson, Ingegerd
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi. Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Näringsforskning.
    Khaw, Kay-Tee
    Wareham, Nicholas J.
    Key, Tim
    Travis, Ruth
    Schmidt, Julie A.
    Merritt, Melissa A.
    Riboli, Elio
    Romieu, Isabelle
    Ferrari, Pietro
    A treelet transform analysis to relate nutrient patterns to the risk of hormonal receptor-defined breast cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC)2016Inngår i: Public Health Nutrition, ISSN 1368-9800, E-ISSN 1475-2727, Vol. 19, nr 2, s. 242-254Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Objective Pattern analysis has emerged as a tool to depict the role of multiple nutrients/foods in relation to health outcomes. The present study aimed at extracting nutrient patterns with respect to breast cancer (BC) aetiology. Design Nutrient patterns were derived with treelet transform (TT) and related to BC risk. TT was applied to twenty-three log-transformed nutrient densities from dietary questionnaires. Hazard ratios (HR) and 95 % confidence intervals computed using Cox proportional hazards models quantified the association between quintiles of nutrient pattern scores and risk of overall BC, and by hormonal receptor and menopausal status. Principal component analysis was applied for comparison. Setting The European Prospective Investigation into Cancer and Nutrition (EPIC). Subjects Women (n 334 850) from the EPIC study. Results The first TT component (TC1) highlighted a pattern rich in nutrients found in animal foods loading on cholesterol, protein, retinol, vitamins B-12 and D, while the second TT component (TC2) reflected a diet rich in -carotene, riboflavin, thiamin, vitamins C and B-6, fibre, Fe, Ca, K, Mg, P and folate. While TC1 was not associated with BC risk, TC2 was inversely associated with BC risk overall (HRQ5 v. Q1=089, 95 % CI 083, 095, P-trend<001) and showed a significantly lower risk in oestrogen receptor-positive (HRQ5 v. Q1=089, 95 % CI 081, 098, P-trend=002) and progesterone receptor-positive tumours (HRQ5 v. Q1=087, 95 % CI 077, 098, P-trend<001). Conclusions TT produces readily interpretable sparse components explaining similar amounts of variation as principal component analysis. Our results suggest that participants with a nutrient pattern high in micronutrients found in vegetables, fruits and cereals had a lower risk of BC.

  • 78. Astvaldsdottir, Alfheidur
    et al.
    Dagerhamn, Jessica
    van Dijken, Jan W. V.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Tandhygienistutbildning.
    Naimi-Akbar, Aron
    Sandborgh-Englund, Gunilla
    Tranaeus, Sofia
    Nilsson, Mikael
    Longevity of posterior resin composite restorations in adults: A systematic review2015Inngår i: Journal of Dentistry, ISSN 0300-5712, E-ISSN 1879-176X, Vol. 43, nr 8, s. 934-954Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Objective: To conduct a systematic review of the literature on the longevity of posterior resin composite restorations in adults. Material and methods: A systematic literature search was conducted according to predetermined criteria for inclusion and exclusion. The studies selected were prospective clinical trials with a minimum follow-up time of 4 years, 40 restorations per experimental group and an annual attrition rate of less than 5%. Initially, abstracts and full-text articles were assessed independently and the assessment was subsequently agreed on by five reviewers. The methodological quality of the studies was assessed according to the Swedish Council on Health Technology Assessment (SBU) standard checklist for determining the extent to which studies meet basic quality criteria. Results: In all, the literature search identified 4275 abstracts and 93 articles were read in fulltext. There were eighteen studies which met the criteria for inclusion, eight of which were included in the analysis. There were 80 failures of restorations with a total follow-up time at risk for failure of 62,030 months. The overall incidence rate for all causes of failure was 1.55 lost restorations per 100 restoration years. The most common biological reason for failure (a total of 31 restorations) was secondary caries, with or without fracture of the restoration. The quality of the evidence was low. Conclusions: In an efficacy setting, the overall survival proportion of posterior resin composite restorations is high. The major reasons for failure are secondary caries and restoration fracture which supports the importance of adequate follow-up time. Clinical significance: The overall survival proportion of posterior composite restorations was high, but the results cannot be extrapolated to an effectiveness setting. The importance of adequate follow-up time is supported by the finding that secondary caries often occurred after 3 years or later.

  • 79.
    Athanassiadis, Tuija
    Umeå universitet, Medicinsk fakultet, Integrativ medicinsk biologi, Fysiologi. Umeå universitet, Medicinsk fakultet, Odontologi.
    Neural circuits engaged in mastication and orofacial nociception2009Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    A deeper understanding of both movement control and the effects of nociceptor inputs on our motor systems is critical for proper clinical diagnosis of musculo-skeletal dysfunctions and for development of novel rehabilitation schemes. In the jaw system, masticatory movements are produced by a central pattern generator (CPG) located in the brainstem. Considerable efforts have been made in deciphering this neuronal network. The present thesis contributes towards an increasingly detailed understanding of its essential elements, and presents a hypothesis of how deep somatic pain (i.e. muscle pain) may be evoked and interferes with the masticatory CPG circuitry.

    In Paper I, the expression of c-Fos-like protein was used as a molecular marker to visualize brainstem neurons that were active during induced fictive mastication in the anesthetized and paralyzed rabbit. Our findings provide a previously lacking detailed record of the neuronal populations that form the masticatory motor pattern. Certain cells were located in brainstem areas previously suggested to be involved in the masticatory CPG. However, it was a new finding that neurons in the dorsal part of the trigeminal main sensory nucleus (NVsnpr-d) may belong to this circuitry. Paper II focused on the discovered neurons in NVsnpr in an in vitro slice preparation from young rats.  Intracellular recordings allowed us to define two cell types based on their response to depolarizing current. Microstimulation applied to the trigeminal motor nucleus, its reticular border, the parvocellular reticular formation and the nucleus reticularis pontis caudalis, elicited postsynaptic potentials in 81% of the neurons tested. Responses obtained were predominately excitatory and sensitive to gluta-matergic antagonists DNQX or/and APV. Some inhibitory and biphasic responses were also evoked. Bicuculline methiodide or strychnine blocked the IPSPs indicating that they were mediated by GABAA or glycinergic receptors. About one third of the stimulations activated both types of neurons antidromically. Neurons in NVsnpr-d seem to gather all the conditions that can theoretically account for a role in masticatory rhythm generation.

    In Paper III, the masticatory model system was used to investigate the possible role of muscle spindle primary afferents in development of persistent musculoskeletal pain. Following intramuscular acidic (pH 4.0) saline injections of rat masseter muscles, in vitro whole cell recordings were done from jaw closing muscle spindle somata located in the trigeminal mesencephalic nucleus (NVmes). Compared to control neurons, the somata of afferents exposed to acid had more hyperpolarized membrane potentials, more hyperpolarized thresholds for firing, high frequency membrane oscillations and ectopic bursting of action potentials. These changes in membrane properties lasted for up to 35 days. Within the same time frame experi-mental animals showed hypersensitivity to touch on the skin covering the injected muscle. Similar saline injections also resulted in a significant increase of activity dependent c-Fos expression in NVmes neurons compared to controls. Immuno-fluorescence and lectin binding studies indicated that small-caliber muscle afferents containing known nociceptor markers (CGRP, SP, P2X3, TRPV1 and IB4) and expressing glutamate receptors are found close to the annulo-spiral endings of the NVmes afferents. Combined, our new observations support the hypothesis that excessive release of glutamate, within muscle spindles due to ectopically evoked antidromic action potentials, could lead to development of persistent musculoskeletal pain by activation and/ or sensitization of adjacent muscle afferent nociceptors.

  • 80.
    Axelsson, Anna
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Tandläkarutbildning.
    Carlsson, Elsa
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Tandläkarutbildning.
    The Effect of Topical Anaesthesia on Pressure Pain Thresholds in symptom-free subjects2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Palpation, a standard procedure in the diagnostic process of muscular pain conditions – myalgia, aims to provoke a muscular pain response. The origin of pain elicited by palpation is not fully understood. There is also a possibility that the pressure elicit response from mechanoreceptors in skin, sub mucosal tissue or periosteum, which may affect the validity of the method.

    The aim of this study was to evaluate the effect of topical anesthesia on pressure pain thresholds at masseter, temporal and thumb muscle sites in healthy individuals.

    Twenty symptom-free subjects (ten males/ ten females) mean age 24.6 years (SD 2.6) participated in this double blind randomized experimental trial. An algometer (Somedic AB) was used to measure Pressure Pain Thresholds (PPT), on the masseter, temporal and thumb before and after topical application of EMLA or a placebo cream.

    There was no statistically significant change in PPTs at any of the tested sites between the baseline and after application of EMLA and placebo cream. Furthermore, there was no significant difference in PPTs between sexes. There was no significant difference in PPTs between the different muscle sites, apart from a higher PPT for the thumb site compared to the masseter muscle.

    In conclusion, PPT was not affected by topical anaesthesia in symptom-free subjects. This indicates that palpation pain is not dermal. Furthermore did PPT not differ between the masseter and temporal muscles. The study indicates that the same palpation pressure may be used for extra-oral palpation of the temporal and masseter muscle for both sexes.

  • 81. Axelsson, S
    et al.
    Söder, B
    Nordenram, G
    Pettersson, LG
    Dahlgren, H
    Norlund, A
    Källestål, C
    Mejare, I
    Lingström, P
    Holm, Anna-Karin
    Umeå universitet, Medicinsk fakultet, Odontologi, Pedodonti.
    Twetman, Svante
    Umeå universitet, Medicinsk fakultet, Odontologi, Pedodonti.
    Effect of combined caries-preventive methods: a systematic review of controlled clinical trials.2004Inngår i: Acta odontologica Scandinavica, Vol. 62, nr 3, s. 163-9Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of this systematic review was to evaluate the caries-preventive effect of combined caries-preventive methods, defined as two or more different interventions in combination, each expected to prevent dental caries. The Medline database was searched for articles published in the period January 1966 to June 2003. Twenty-four controlled studies met the inclusion criteria, and their value as evidence was assessed according to predetermined criteria. The level of evidence for the overall conclusion regarding each method was graded according to the protocol of the Swedish Council on Technology Assessment in Health Care. The scientific evidence for the combination of treatments involving fluoride that had a preventive effect on caries in children and adolescents was graded as moderate. However, for elderly patients the scientific evidence for the caries-preventive effect of different combinations of treatments was found to be incomplete. No conclusion could be drawn regarding the evidence for combinations of treatments being effective for groups at high caries risk, as the results from the identified clinical studies were conflicting.

  • 82.
    Azizi, Asal
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Hasan, Zainab
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Presence of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis in Children with Clinical Signs of Periodontitis, Living in the Västerbotten County, Sweden2016Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    This study has examined the presence of A. actinomycetemcomitans and Porphyromonas gingivalis, in 10 children and adolescents in Västerbotten County, who had been referred to the Department of Pediatric Dentistry due to suspected periodontal disease. Based on previous studies we hypothesized that the majority of the enrolled subjects would be hosts for A. actinomycetemcomitans. A second hypothesis was that a relationship between periodontal disease and heredity would be found.  

    The aim was to study to which extent the enrolled patients were infected with A. actinomycetemcomitans and to enhance the general knowledge of the bacterial composition in children/adolescents with clinical signs of periodontal disease. Another aim was to examine the nature of the disease in relation to heredity, oral habits and ethnicity. A third aim was to compare PCR and cultivations for detection of pathogens.    

    Sampling was made from pathological periodontal pockets by a dentist or a dental hygienist. Samples were sent to a laboratory for analysis by two different methods: cultivation and PCR.

    Our results showed that the majority of the participants had non-European ethnicity, were positive for A. actinomycetemcomitans and 3 of 7 A. actinomycetemcomitans-positive subjects exhibited high leukotoxicity. No subject harbored the JP2 leukotoxin promoter genotype. Serotypes a-d and f, but not e, were detected.

    We concluded that the majority of the patients were infected with A. actinomycetemcomitans, some of them had high leukotoxicity but none of them had the JP2-genotype. The culture based analysis was similar in terms of detecting A. actinomycetemcomitans compared to the PCR method.

  • 83. Baldock, PA
    et al.
    Allison, SJ
    Lundberg, Pernilla
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Lee, NJ
    Slack, K
    Lin, EJ
    Enriquez, RF
    McDonald, MM
    Zhang, L
    During, MJ
    Little, DG
    Eisman, JA
    Gardiner, EM
    Yulyaningsih, E
    Lin, S
    Sainsbury, A
    Herzog, H
    Novel role of Y1 receptors in the coordinated regulation of bone and energy homeostasis.2007Inngår i: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 282, nr 26, s. 19092-19102Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The importance of neuropeptide Y (NPY) and Y2 receptors in the regulation of bone and energy homeostasis has recently been demonstrated. However, the contributions of the other Y receptors are less clear. Here we show that Y1 receptors are expressed on osteoblastic cells. Moreover, bone and adipose tissue mass are elevated in Y1(-/-) mice with a generalized increase in bone formation on cortical and cancellous surfaces. Importantly, the inhibitory effects of NPY on bone marrow stromal cells in vitro are absent in cells derived from Y1(-/-) mice, indicating a direct action of NPY on bone cells via this Y receptor. Interestingly, in contrast to Y2 receptor or germ line Y1 receptor deletion, conditional deletion of hypothalamic Y1 receptors in adult mice did not alter bone homeostasis, food intake, or adiposity. Furthermore, deletion of both Y1 and Y2 receptors did not produce additive effects in bone or adiposity. Thus Y1 receptor pathways act powerfully to inhibit bone production and adiposity by nonhypothalamic pathways, with potentially direct effects on bone tissue through a single pathway with Y2 receptors.

  • 84. Bamia, C
    et al.
    Orfanos, P
    Ferrari, P
    Overvad, K
    Hundborg, HH
    Tjonneland, A
    Olsen, A
    Kesse, E
    Boutron-Ruault, MC
    Clavel-Chapelon, F
    Nagel, G
    Boffetta, P
    Boeing, H
    Hoffmann, K
    Trichopoulos, D
    Baibas, N
    Psaltopoulou, T
    Norat, T
    Slimani, N
    Palli, D
    Krogh, V
    Panico, S
    Tumino, R
    Sacerdote, C
    Bueno-de-Mesquita, HB
    Ocke, MC
    Peeters, PH
    van Rossum, CT
    Quiros, JR
    Sanchez, MJ
    Navarro, C
    Barricarte, A
    Dorronsoro, M
    Berglund, G
    Wirfalt, E
    Hallmans, Göran
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Näringsforskning.
    Johansson, Ingegerd
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Kariologi.
    Bingham, S
    Khaw, KT
    Spencer, EA
    Roddam, AW
    Riboli, E
    Trichopoulou, A
    Dietary patterns among older Europeans: the EPIC-Elderly study.2005Inngår i: British Journal of Nutrition, ISSN 0007-1145, E-ISSN 1475-2662, Vol. 94, nr 1, s. 100-13Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Overall dietary patterns have been associated with health and longevity. We used principal component (PC) and cluster analyses to identify the prevailing dietary patterns of 99 744 participants, aged 60 years or older, living in nine European countries and participating in the European Prospective Investigation into Cancer and Nutrition (EPIC-Elderly cohort) and to examine their socio-demographic and lifestyle correlates. Two PC were identified: PC1 reflects a 'vegetable-based' diet with an emphasis on foods of plant origin, rice, pasta and other grain rather than on margarine, potatoes and non-alcoholic beverages. PC2 indicates a 'sweet- and fat-dominated' diet with a preference for sweets, added fat and dairy products but not meat, alcohol, bread and eggs. PC1 was associated with a younger age, a higher level of education, physical activity, a higher BMI, a lower waist:hip ratio and never and past smoking. PC2 was associated with older age, less education, never having smoked, a lower BMI and waist:hip ratio and lower levels of physical activity. Elderly individuals in southern Europe scored positively on PC1 and about zero on PC2, whereas the elderly in northern Europe scored negatively on PC1 and variably on PC2. The results of cluster analysis were compatible with the indicated dietary patterns. 'Vegetable-based' and a 'sweet- and fat-dominated' diets are prevalent among the elderly across Europe, and there is a north-south gradient regarding their dietary choices. Our study contributes to the identification of groups of elderly who are likely to have different prospects for long-term disease occurrence and survival.

  • 85. Bamia, Christina
    et al.
    Trichopoulos, Dimitrios
    Ferrari, Pietro
    Overvad, Kim
    Bjerregaard, Lone
    Tjønneland, Anne
    Halkjaer, Jytte
    Clavel-Chapelon, Françoise
    Kesse, Emmanuelle
    Boutron-Ruault, Marie-Christine
    Boffetta, Paolo
    Nagel, Gabriele
    Linseisen, Jacob
    Boeing, Heiner
    Hoffmann, Kurt
    Kasapa, Christina
    Orfanou, Anastasia
    Travezea, Chrysoula
    Slimani, Nadia
    Norat, Teresa
    Palli, Domenico
    Pala, Valeria
    Panico, Salvatore
    Tumino, Rosario
    Sacerdote, Carlotta
    Bueno-de-Mesquita, H Bas
    Waijers, Patricia M C M
    Peeters, Petra H M
    van der Schouw, Yvonne T
    Berenguer, Antonio
    Martinez-Garcia, Carmen
    Navarro, Carmen
    Barricarte, Aurelio
    Dorronsoro, Miren
    Berglund, Göran
    Wirfält, Elisabet
    Johansson, Ingegerd
    Umeå universitet, Medicinsk fakultet, Odontologi, Kariologi.
    Johansson, Gerd
    Umeå universitet, Medicinsk fakultet, Folkhälsa och klinisk medicin, Näringsforskning.
    Bingham, Sheila
    Khaw, Kay-Tee
    Spencer, Elizabeth A
    Key, Tim
    Riboli, Elio
    Trichopoulou, Antonia
    Dietary patterns and survival of older Europeans: the EPIC-Elderly Study (European Prospective Investigation into Cancer and Nutrition).2007Inngår i: Public Health Nutrition, ISSN 1368-9800, E-ISSN 1475-2727, Vol. 10, nr 6, s. 590-8Artikkel i tidsskrift (Fagfellevurdert)
  • 86. Bao, Kai
    et al.
    Bostanci, Nagihan
    Thurnheer, Thomas
    Grossmann, Jonas
    Wolski, Witold E.
    Thay, Bernard
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Belibasakis, Georgios N.
    Oscarsson, Jan
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Aggregatibacter actinomycetemcomitans H-NS promotes biofilm formation and alters protein dynamics of other species within a polymicrobial oral biofilm2018Inngår i: npj Biofilms and Microbiomes, ISSN 2055-5008, Vol. 4, nr 12, s. 1-11Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aggregatibacter actinomycetemcomitans is a Gram-negative organism, strongly associated with aggressive forms of periodontitis. An important virulence property of A. actinomycetemcomitans is its ability to form tenacious biofilms that can attach to abiotic as well as biotic surfaces. The histone-like (H-NS) family of nucleoid-structuring proteins act as transcriptional silencers in many Gram-negative bacteria. To evaluate the role of H-NS in A. actinomycetemcomitanshns mutant derivatives of serotype a strain D7S were generated. Characteristics of the hns mutant phenotype included shorter and fewer pili, and substantially lower monospecies biofilm formation relative to the wild type. Furthermore, the D7S hns mutant exhibited significantly reduced growth within a seven-species oral biofilm model. However, no apparent difference was observed regarding the numbers and proportions of the remaining six species regardless of being co-cultivated with D7S hnsor its parental strain. Proteomics analysis of the strains grown in monocultures confirmed the role of H-NS as a repressor of gene expression in A. actinomycetemcomitans. Interestingly, proteomics analysis of the multispecies biofilms indicated that the A. actinomycetemcomitanswild type and hns mutant imposed different regulatory effects on the pattern of protein expression in the other species, i.e., mainly Streptococcus spp., Fusobacterium nucleatum, and Veillonella dispar. Gene ontology analysis revealed that a large portion of the differentially regulated proteins was related to translational activity. Taken together, our data suggest that, apart from being a negative regulator of protein expression in A. actinomycetemcomitans, H-NS promotes biofilm formation and may be an important factor for survival of this species within a multispecies biofilm.

  • 87. Becker, William
    et al.
    Sennerby, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Käkkirurgi. Department of Biomaterials, Institute for Surgical Sciences, University of Gothenburg.
    Bedrossian, Edwin
    Becker, Burton E
    Lucchini, Jean Pierre
    Implant stability measurements for implants placed at the time of extraction: a cohort, prospective clinical trial2005Inngår i: Journal of Periodontology, ISSN 0022-3492, E-ISSN 1943-3670, Vol. 76, nr 3, s. 391-397Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: Studies indicate that implants placed at the time of extraction have high success rates. Implants must be stable at the time of insertion. Presently there are no data indicating the degree of implant stability when implants are placed at the time of extraction. This study evaluated changes in stability of implants from implant placement to abutment connection utilizing resonance frequency analysis (RFA). The unit of measurement was the international stability quotient (ISQ).

    Methods: Prior to treatment, patients were given medical history and dental evaluations. Periapical and panogram radiographs were taken. Fifty-two patients requiring extraction of one or two teeth and implant placement immediately after extraction were enrolled in this study. Under conscious sedation and local anesthesia or local anesthesia alone, teeth were atraumatically removed and the extraction sockets were debrided. A total of 73 dental implants (57 in the maxilla, 16 in the mandible) were placed. Using a one-stage approach, all implants were placed within the patient's alveolar envelope and were never placed directly into extraction sockets. All implants were placed into contained extraction sites. Bone augmentation procedures were not performed. After implant insertion, the RFA electronic transducer was attached to the head of the implant with the retaining screw. The device was attached to a computer designed to register RFA scores in ISQ units. RFA measurements were taken at implant placement and abutment connection. Bone qualities, quantity, implant length and width as well as site of placement were recorded.

    Results: The average interval between implant insertion and abutment connection was 5.6 months (SD 2.05). Two implants were lost between implant insertion and 1 year. At 2 to 3 years, the cumulative survival was 97.2%. Resonance frequency measurements at implant placement showed a mean primary stability of 62.0 (SE 1.1; range 43 to 83 ISQ) and a mean secondary stability after 1 year of 64.0 (SE 1.2; range 40 to 98 ISQ) for all implants. The increase was marginally significant (generalized estimating equation z-statistic = 1.79; P value = 0.07).

    Conclusions: Implants placed at the time of extraction and inserted into native bone and not directly into extractions sockets have a high degree of initial stability as evidenced by RFA measurements. Implants with initial high ISQ levels revealed a slight drop in levels over time, while implants with levels lower than 60 had increases in levels between implant insertion and abutment connection. At 2 to 3 years the cumulative survival rate was 97.2%.

  • 88.
    Behnam Motlagh, Parviz
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap.
    Tyler, Andreas
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap.
    Johansson, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Brännstrom, Thomas
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap.
    Grankvist, Kjell
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap.
    Co-expression of Globotriasosylceramide (Gb3) With MDR1 in Cisplatin-resistant Pleural Mesothelioma and Non-small Cell Lung Cancer Cell May Lead to a New Tumour Resistance Treatment Approach2011Konferansepaper (Fagfellevurdert)
  • 89.
    Behnam-Mothlag, Parviz
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Klinisk kemi.
    Tyler, Andreas
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Klinisk kemi.
    Brännström, Thomas
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Karlsson, Terese
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Johansson, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Molekylär paradontologi.
    Grankvist, Kjell
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Klinisk kemi.
    Cisplatin Resistance in Malignant Pleural Mesothelioma2012Inngår i: Mesotheliomas: Synonyms and Definition, Epidemiology, Etiology, Pathogenesis, Cyto-Histopathological Features, Clinic, Diagnosis, Treatment, Prognosis / [ed] Alexander Zubritsky, Zagreb: InTech, 2012, Vol. 11, s. 169-186Kapittel i bok, del av antologi (Fagfellevurdert)
  • 90.
    Behnam-Motlagh, Parviz
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Klinisk kemi.
    Tyler, Andreas
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Klinisk kemi.
    Grankvist, Kjell
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Klinisk kemi.
    Johansson, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Verotoxin-1 Treatment or Manipulation of its Receptor Globotriaosylceramide (Gb3) for Reversal of Multidrug Resistance to Cancer Chemotherapy2010Inngår i: Toxins, ISSN 2072-6651, Vol. 2, nr 10, s. 2467-2477Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    A major problem with anti-cancer drug treatment is the development of acquired multidrug resistance (MDR) of the tumor cells. Verotoxin-1 (VT-1) exerts its cytotoxicity by targeting the globotriaosylceramide membrane receptor (Gb3), a glycolipid associated with multidrug resistance. Gb3 is overexpressed in many human tumors and tumor cell lines with inherent or acquired MDR. Gb3 is co-expressed and interplays with the membrane efflux transporter P-gp encoded by the MDR1 gene. P-gp could act as a lipid flippase and stimulate Gb3 induction when tumor cells are exposed to cancer chemotherapy. Recent work has shown that apoptosis and inherent or acquired multidrug resistance in Gb3-expressing tumors could be affected by VT-1 holotoxin, a sub-toxic concentration of the holotoxin concomitant with chemotherapy or its Gb3-binding B-subunit coupled to cytotoxic or immunomodulatory drug, as well as chemical manipulation of Gb3 expression. The interplay between Gb3 and P-gp thus gives a possible physiological approach to augment the chemotherapeutic effect in multidrug resistant tumors.

  • 91. Belibasakis, George
    et al.
    Brage, Monica
    Umeå universitet, Medicinsk fakultet, Odontologi, Parodontologi. Umeå universitet, Medicinsk fakultet, Medicinsk biovetenskap, Patologi.
    Lagergård, Teresa
    Johansson, Anders
    Umeå universitet, Medicinsk fakultet, Odontologi.
    Cytolethal distending toxin upregulates RANKL expression in Jurkat T-cells: Cdt upregulates RANKL2008Inngår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS), ISSN 0903-4641, E-ISSN 1600-0463, Vol. 116, nr 6, s. 499-506Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cytolethal distending toxin, a bacterial exotoxin produced by a number of Gram-negative species, causes growth arrest and morphological alterations in host cells. Among these species are Haemophilus ducreyi, the etiological agent of chancroid, and the periodontal pathogen Aggregatibacter actinomycetemcomitans, highly implicated in localized aggressive periodontitis. CDT induces receptor activator of NF-kappaB ligand (RANKL) expression in periodontal fibroblasts, the key bone-resorbing cytokine. T-cells are actively involved in localized inflammation-induced bone destruction, including periodontitis. The aim of this study was to investigate the effects of purified CDT on the expression of RANKL and its decoy receptor osteoprotegerin (OPG), in the Jurkat T-cell line. Quantitative real-time PCR indicated that 100 pg/ml of purified H. ducreyi CDT upregulated RANKL mRNA expression by 2.2-fold, after 24 h of exposure. This increase was corroborated by a 2.0-fold increase in RANKL protein release, as determined by ELISA. OPG was not detected in this experimental system. In conclusion, CDT enhances RANKL expression in T-cells, denoting that these cells are a potential target for the toxin and strengthening the potential link between this virulence factor and mechanisms associated with localized bone resorption.

  • 92.
    Belibasakis, Georgios
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Johansson, Anders
    Umeå universitet, Medicinsk fakultet, Odontologi, Parodontologi.
    Wang, Ying
    Claesson, Rolf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Chen, Casey
    Asikainen, Sirkka
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Kalfas, Sotos
    Inhibited proliferation of human periodontal ligament cells and gingival fibroblasts by Actinobacillus actinomycetemcomitans: involvement of the cytolethal distending toxin2002Inngår i: European Journal of Oral Sciences, ISSN 0909-8836, E-ISSN 1600-0722, Vol. 110, nr 5, s. 366-373Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Actinobacillus actinomycetemcomitans can inhibit fibroblast proliferation. The objective of this study was to characterize the early proliferative responses of human periodontal ligament cells (PDLC) and gingival fibroblasts (GF) to A. actinomycetemcomitans components and to investigate the possible involvement of the cytolethal distending toxin (cdt) produced by this bacterium. The PDLC and GF were challenged with surface components of A. actinomycetemcomitans. Both DNA and protein synthesis as well as cell lysis or apoptosis were assayed for a 6-h period after addition of the bacterial extract. Unlike the controls, inhibition of DNA synthesis had already occurred in the challenged cells at the end of the initial 3- to 6-h period. No lysis or apoptosis was detected, and the total protein synthesis remained unaffected. The persistence of the effect on cell growth was confirmed after a 72-h period of challenge, during which the cells remained viable but exhibited an elongated and distended cell body. No significant differences were observed between PDLC and GF. When a cdt-knockout strain of A. actinomycetemcomitans was used almost no inhibitory effect on cell proliferation was observed. It was concluded that A. actinomycetemcomitans causes a non-lethal inhibition of proliferation in PDLC and GF as a result of an early arrest of DNA synthesis. Cytolethal distending toxin is responsible for most of this effect. This bacterial property may compromise tissue homeostasis in the periodontium.

  • 93.
    Belibasakis, Georgios N.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi. Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Cellular and molecular responses of periodontal connective tissue cells to Actinobacillus actinomycetemcomitans cytolethal distending toxin2004Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Actinobacillus actinomycetemcomitans is present in elevated proportions and numbers in dental bacterial biofilms of patients with localized aggressive periodontitis. This variant of periodontal disease, occurring in adolescents and young adults, is characterized by rapid and severe destruction of the connective tissues and bone supporting the teeth, eventually culminating in tooth loss. The cytolethal distending toxin (Cdt) is a newly discovered bacterial protein toxin, uniquely present in A. actinomycetemcomitans among all known to-date oral bacterial species. The Cdt has the capacity to inhibit mammalian cell growth, but its putative role in the pathogenesis of the disease is unclear. The aim of this in vitro work has been to study the effects of A. actinomycetemcomitans on periodontal connective tissue cell cultures, and to evaluate the possible involvement of its Cdt.

    A. actinomycetemcomitans inhibited the proliferation of gingival and periodontal ligament fibroblasts, as a result of a combined arrest at the G1 and G2/M phases of the cell cycle. This growth inhibition was non-lethal and the cells remained metabolically active, although their DNA synthesis was reduced. The intoxicated cells exhibited increased size and irregular structure, characterized by distension and elongation. This cellular enlargement occurred in both G1 and G2/M phase arrested cells. The Cdt of A. actinomycetemcomitans was responsible for the observed growth inhibition, as well as the concomitant morphological alterations.

    The possible induction of inflammatory cytokines related to bone resorption was investigated in response to A. actinomycetemcomitans, and the involvement of Cdt was evaluated. Extensive focus was given to the study of receptor activator of NF-κB ligand (RANKL) expression, a membrane-bound ligand that signals osteoclast progenitors to differentiate and fuse into mature osteoclasts, activating bone resorption. It was demonstrated that A. actinomycetemcomitans induced RANKL mRNA and protein expression in the cells studied, but did not affect the expression of its decoy receptor, osteoprotegerin. This induction was solely attributed to its Cdt, as demonstrated by the use of a cdt-knockout A. actinomycetemcomitans strain, purified recombinant Cdt, and antibodies blocking the Cdt. In addition, this event was not mediated by pro-inflammatory cytokines known to stimulate RANKL. Interleukin-6 mRNA and protein expression were also enhanced by A. actinomycetemcomitans, but Cdt had limited involvement in this enhancement.

    In conclusion, two distinct mechanisms by which A. actinomycetemcomitans Cdt may be involved in the pathogenesis of localized aggressive periodontitis are proposed. Firstly, the growth arrest of the resident fibroblasts may impair the physiological connective tissue remodelling equilibrium and lead to connective tissue attachment loss. Secondly, the induction of RANKL by these cells, residing in the proximity of the alveolar bone, may locally stimulate osteoclastogenesis and promote alveolar bone resorption. This work also provides further insights to the understanding of Cdt mechanisms of action, contributing to the global characterization of the toxin’s virulence.

  • 94. Belibasakis, Georgios N
    et al.
    Johansson, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Molekylär paradontologi.
    Aggregatibacter actinomycetemcomitans targets NLRP3 and NLRP6 inflammasome expression in human mononuclear leukocytes2012Inngår i: Cytokine, ISSN 1043-4666, E-ISSN 1096-0023, Vol. 59, nr 1, s. 124-130Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Periodontitis is an inflammatory condition that destroys the tooth-supporting tissues, as a result of local bacterial infection. Aggregatibacter actinomycetemcomitans is a Gram-negative facultative anaerobic species, highly associated with aggressive periodontitis. Periodontal inflammation is dominated by cytokines of the Interleukin (IL)-1 family. Prior to their secretion by mononuclear cells, IL-1 cytokines are processed by intracellular protein complexes, known as "inflammasomes", which can sense the bacterial challenge. The aim of this study was to investigate which inflammasomes are regulated in mononuclear cells in response to A. actinomycetemcomitans. The D7SS strain and its derivative leukotoxin and cytolethal distending toxin knock-out mutant strains were used to infect human mononuclear cells at a 1:10 cell: bacteria ratio, for 3h. The expression of various inflammasome components in the cells was investigated by TaqMan quantitative real-time polymerase chain reaction (qPCR). The expressions of NOD-like receptor protein (NLRP)1, NLRP2 and Absent In Melanoma (AIM)2 inflammasome sensors, as well as their effector Caspase-1 were not affected. However, NLRP3 was up-regulated, while NLRP6 was down-regulated. This effect was not dependent on the leukotoxin or the cytolethal distending toxin, as demonstrated by the use of specific gene knock-out mutant strains. IL-1β and IL-18 expressions were also up-regulated by the bacterial challenge. In conclusion, A. actinomycetemcomitans enhances NLRP3 and reduces NLRP6 inflammasome expression, irrespective of its major virulence factors, confirming the high pathogenic profile of this species, and providing further insights to the mechanisms of periodontal inflammation.

  • 95.
    Belibasakis, Georgios N
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi. Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Johansson, Anders
    Umeå universitet, Medicinsk fakultet, Odontologi, Parodontologi.
    Wang, Y
    Chen, C
    Kalfas, S
    Lerner, Ulf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    The cytolethal distending toxin induces receptor activator of NF-κB ligand expression in human gingival fibroblasts and periodontal ligament cells2005Inngår i: Infection and Immunity, ISSN 0019-9567, E-ISSN 1098-5522, Vol. 73, nr 1, s. 342-351Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Actinobacillus actinomycetemcomitans is associated with localized aggressive periodontitis, a disease characterized by rapid loss of the alveolar bone surrounding the teeth. Receptor activator of NF-kappaB Ligand (RANKL) and osteoprotegerin (OPG) are two molecules that regulate osteoclast formation and bone resorption. RANKL induces osteoclast differentiation and activation, whereas OPG blocks this process by acting as a decoy receptor for RANKL. The purpose of this study was to investigate the effect of A. actinomycetemcomitans on the expression of RANKL and OPG in human gingival fibroblasts and periodontal ligament cells. RANKL mRNA expression was induced in both cell types challenged by A. actinomycetemcomitans extract, whereas OPG mRNA expression remained unaffected. Cell surface RANKL protein was also induced by A. actinomycetemcomitans, whereas there was no change in OPG protein secretion. A cytolethal distending toxin (Cdt) gene-knockout strain of A. actinomycetemcomitans did not induce RANKL expression, in contrast to its wild-type strain. Purified Cdt from Haemophilus ducreyi alone, or in combination with extract from the A. actinomycetemcomitans cdt mutant strain, induced RANKL expression. Pretreatment of A. actinomycetemcomitans wild-type extract with Cdt antiserum abolished RANKL expression. In conclusion, A. actinomycetemcomitans induces RANKL expression in periodontal connective tissue cells. Cdt is crucial for this induction and may therefore be involved in the pathological bone resorption during the process of localized aggressive periodontitis.

  • 96.
    Belibasakis, Georgios N
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi. Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Johansson, Anders
    Umeå universitet, Medicinsk fakultet, Odontologi, Parodontologi.
    Wang, Y
    Chen, C
    Lagergård, T
    Kalfas, S
    Lerner, Ulf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Cytokine responses of human gingival fibroblasts to Actinobacillus actinomycetemcomitans cytolethal distending toxin2005Inngår i: Cytokine, ISSN 1043-4666, E-ISSN 1096-0023, Vol. 30, nr 2, s. 56-63Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Actinobacillus actinomycetemcomitans is implicated in the pathogenesis of localized aggressive periodontitis, and has the capacity to express a cytolethal distending toxin (Cdt). Gingival fibroblasts (GF) are resident cells of the periodontium, which can express several osteolytic cytokines. The aims of this study were a) to investigate the role of Cdt in A. actinomycetemcomitans-induced expression of osteolytic cytokines and their cognate receptors in GF and b) to determine if the previously demonstrated induction of receptor activator of NFkappaB ligand (RANKL) by A. actinomycetemcomitans is mediated by these pro-inflammatory cytokines or by prostaglandin E(2) (PGE(2)). A. actinomycetemcomitans clearly induced interleukin (IL)-6, IL-1beta, and to a minimal extent, tumor necrosis factor (TNF)-alpha mRNA expression. At the protein level, IL-6 but not IL-1beta or TNF-alpha expression was stimulated. The mRNA expression of the different receptor subtypes recognizing IL-6, IL-1beta and TNF-alpha was not affected. A cdt-knockout strain of A. actinomycetemcomitans had similar effects on cytokine and cytokine receptor mRNA expression, compared to its parental wild-type strain. Purified Cdt stimulated IL-6, but not IL-1beta or TNF-alpha protein biosynthesis. Antibodies neutralizing IL-6, IL-1 or TNF-alpha, and the PGE(2) synthesis inhibitor indomethacin, did not affect A. actinomycetemcomitans-induced RANKL expression. In conclusion, a) A. actinomycetemcomitans induces IL-6 production in GF by a mechanism largely independent of its Cdt and b) A. actinomycetemcomitans-induced RANKL expression in GF occurs independently of IL-1, IL-6, TNF-alpha, or PGE(2).

  • 97.
    Belibasakis, Georgios N
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi. Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Mattsson, Anna
    Umeå universitet, Medicinsk fakultet, Odontologi, Parodontologi.
    Wang, Ying
    Chen, Casey
    Johansson, Anders
    Umeå universitet, Medicinsk fakultet, Odontologi, Parodontologi.
    Cell cycle arrest of human gingival fibroblasts and periodontal ligament cells by Actinobacillus actinomycetemcomitans: involvement of the cytolethal distending toxin2004Inngår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS), ISSN 0903-4641, E-ISSN 1600-0463, Vol. 112, nr 10, s. 674-685Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The cytolethal distending toxin (Cdt) is produced by several Gram-negative bacterial species and causes growth arrest and morphological alterations in mammalian cells. Actinobacillus actinomycetemcomitans, which is involved in the pathogenesis of localized aggressive periodontitis, also produces a Cdt that affects periodontal connective tissue cells. The aim of this study was to investigate in which phase of the cell cycle these cells are arrested and enlarged when challenged with A. actinomycetemcomitans, and to evaluate the involvement of its Cdt. Human gingival fibroblasts and periodontal ligament cells were challenged with A. actinomycetemcomitans extract, or with purified Cdt, and cell cycle analysis was performed by propidium iodide staining and flow cytometry. Cells exposed to an A. actinomycetemcomitans wild-type strain, or to purified Cdt, were arrested in both G1 and G2/M phases, and appeared enlarged compared to the corresponding controls. The cellular enlargement occurred in both G1 and G2/M arrested cells. In contrast, cells exposed to an A. actinomycetemcomitans cdt-knockout mutant strain showed cell cycle phase distribution and size similar to the controls. In conclusion, A. actinomycetemcomitans causes a combined G1 and G2/M growth arrest and enlargement in periodontal connective tissue cells, which is attributed to its Cdt.

  • 98. Belibasakis, GN
    et al.
    Bostanci, N
    Hashim, A
    Johansson, Anders
    Umeå universitet, Medicinsk fakultet, Odontologi, Parodontologi.
    Aduse-Opoku, J
    Curtis, MA
    Hughes, FJ
    Regulation of RANKL and OPG gene expression in human gingival fibroblasts and periodontal ligament cells by Porphyromonas gingivalis: a putative role of the Arg-gingipains2007Inngår i: Microbial Pathogenesis, ISSN 0882-4010, E-ISSN 1096-1208, Vol. 43, nr 1, s. 46-53Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Porphyromonas gingivalis is highly implicated in the pathogenesis of periodontitis, which is characterized by the destruction of periodontal connective tissues and the supporting alveolar bone. Receptor Activator of NF-kappaB Ligand (RANKL) stimulates bone resorption, whereas osteoprotegerin (OPG) blocks its action, and this bi-molecular system is implicated in periodontitis. The aim of this work was (a) to investigate the regulation of RANKL and OPG gene expression in human periodontal ligament (PDL) cells and gingival fibroblasts (GF), in response to P. gingivalis culture supernatants, by quantitative real-time PCR and (b) to attempt to identify putative virulence factors involved in this process. The results indicated that P. gingivalis induced RANKL and reduced OPG mRNA expression by the studied cells, resulting in an increased RANKL/OPG expression ratio. Heat-inactivation of P. gingivalis resulted in significant reduction of RANKL mRNA expression. A Lys-gingipain mutant strain did not affect, whereas an Arg-gingipain mutant strain further enhanced RANKL mRNA expression, compared to their parental wild-type strain. In conclusion, P. gingivalis up-regulates the RANKL/OPG expression ratio in GF and PDL cells, denoting an enhanced osteoclastogenic potential by the cells. The component mainly responsible for RANKL induction appears to be proteinaceous, and it may be regulated by the Arg-gingipains.

  • 99. Benetou, V
    et al.
    Orfanos, P
    Pettersson-Kymmer, Ulrika
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap.
    Bergström, Ulrica
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Svensson, Olle
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Johansson, Ingegerd
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Kariologi.
    Berrino, F
    Tumino, R
    Borch, K B
    Lund, E
    Peeters, P H M
    Grote, V
    Li, K
    Altzibar, J M
    Key, T
    Boeing, H
    von Ruesten, A
    Norat, T
    Wark, P A
    Riboli, E
    Trichopoulou, A
    Mediterranean diet and incidence of hip fractures in a European cohort2013Inngår i: Osteoporosis International, ISSN 0937-941X, E-ISSN 1433-2965, Vol. 24, nr 5, s. 1587-1598Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Prevention of hip fractures is of critical public health importance. In a cohort of adults from eight European countries, evidence was found that increased adherence to Mediterranean diet, measured by a 10-unit dietary score, is associated with reduced hip fracture incidence, particularly among men. INTRODUCTION: Evidence on the role of dietary patterns on hip fracture incidence is scarce. We explored the association of adherence to Mediterranean diet (MD) with hip fracture incidence in a cohort from eight European countries. METHODS: A total of 188,795 eligible participants (48,814 men and 139,981 women) in the European Prospective Investigation into Cancer and nutrition study with mean age 48.6 years (±10.8) were followed for a median of 9 years, and 802 incident hip fractures were recorded. Diet was assessed at baseline through validated dietary instruments. Adherence to MD was evaluated by a MD score (MDs), on a 10-point scale, in which monounsaturated were substituted with unsaturated lipids. Association with hip fracture incidence was assessed through Cox regression with adjustment for potential confounders. RESULTS: Increased adherence to MD was associated with a 7 % decrease in hip fracture incidence [hazard ratio (HR) per 1-unit increase in the MDs 0.93; 95 % confidence interval (95 % CI) = 0.89-0.98]. This association was more evident among men and somewhat stronger among older individuals. Using increments close to one standard deviation of daily intake, in the overall sample, high vegetable (HR = 0.86; 95 % CI = 0.79-0.94) and high fruit (HR = 0.89; 95 % CI = 0.82-0.97) intake was associated with decreased hip fracture incidence, whereas high meat intake (HR = 1.18; 95 % CI = 1.06-1.31) with increased incidence. Excessive ethanol consumption (HR high versus moderate = 1.74; 95 % CI = 1.32-2.31) was also a risk factor. CONCLUSIONS: In a prospective study of adults, increased adherence to MD appears to protect against hip fracture occurrence, particularly among men.

  • 100. Benetou, V
    et al.
    Orfanos, P
    Zylis, D
    Sieri, S
    Contiero, P
    Tumino, R
    Giurdanella, M C
    Peeters, P H M
    Linseisen, J
    Nieters, A
    Boeing, H
    Weikert, C
    Pettersson, U
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk farmakologi.
    Johansson, Ingegerd
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Kariologi.
    Bueno-de-Mesquita, H B
    Dorronsoro, M
    Boffetta, P
    Trichopoulou, A
    Diet and hip fractures among elderly Europeans in the EPIC cohort2011Inngår i: European Journal of Clinical Nutrition, ISSN 0954-3007, E-ISSN 1476-5640, Vol. 65, nr 1, s. 132-139Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In a prospective study of the elderly, diet, including consumption of dairy products, alcohol and vitamin D, did not appear to play a major role in hip fracture incidence. There is however, weak and statistically non-significant evidence that vegetable and fish consumption and intake of polyunsaturated lipids may have a beneficial, whereas saturated lipid intake a detrimental effect.

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