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  • 1. Ahlgren, Camilla
    et al.
    Molin, Margareta
    Umeå universitet, Medicinsk fakultet, Odontologi, Protetik. Umeå universitet, Medicinsk fakultet, Odontologi.
    Lundh, Thomas
    Nilner, Krister
    Levels of gold in plasma after dental gold inlay insertion.2007Ingår i: Acta odontologica Scandinavica, ISSN 1502-3850, Vol. 65, nr 6, s. 331-4Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    OBJECTIVE: Several studies have reported increased levels of gold (Au) in the blood of patients with dental gold restorations. This study analyzed gold levels in blood plasma before dental gold inlay insertion, 0-12 months after, and 15 years after. MATERIAL AND METHODS: Plasma samples from 9 patients were taken before and 0-10 months after gold inlay insertion. Fifteen years after gold inlay insertion, further blood samples taken from 8 of these patients were analyzed for gold using inductively coupled plasma mass spectrometry. An oral examination was also carried out before and 15 years after gold inlay insertion. RESULTS: Gold levels in plasma were significantly higher 0-12 months after gold inlay insertion than before treatment (p=0.008). No significant difference in gold plasma levels was found between 0-12 months after and 15 years after insertion (p=0.109), although there was a significant correlation between the number of gold alloy surfaces and the amount of gold in plasma 15 years after insertion (p=0.028). CONCLUSIONS: This study supports a dose-related release of gold into plasma from dental gold restorations, a release that appears to be stable over time.

  • 2. Derand, Tore
    et al.
    Molin, Margareta
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Protetik.
    Kvam, Ketil
    Bond strength of a composite luting agent to alumina ceramic surfaces.2006Ingår i: Acta Odontologica Scandinavica, ISSN 0001-6357, E-ISSN 1502-3850, Vol. 64, nr 4, s. 227-30Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    OBJECTIVE: The purpose of this study was to evaluate the shear bond strength (SBS) of a dental luting agent to alumina ceramics after different surface pretreatment. MATERIAL AND METHODS: Specimens (n=50) of pressed blocks (10 x 0 x 5 mm) of alumina ceramic (Procera AllCeram) were divided into untreated specimens (AF) as provided by the manufacturer and polished specimens (AP). Five groups of specimens (n=5 x 10) with different surface pretreatments were prepared. Groups 1 and 2: AF and AP without any pretreatment; Group 3: AF treated with silane, (AF-s); Group 4: AF treated with RF plasma spray (AF-RF); Group 5: AF treated with low fusing porcelain (AF-p) glass pearls. Composite cylinders (5 x 5 mm) were cemented to the test specimens with a resin luting agent. The specimens were loaded to failure in shear mode using a universal testing machine. Recorded loads were used to calculate SBS in MPa. The results were analyzed using one-way ANOVA and the Tukey HSD multiple comparison test at alpha = 0.05. Scanning electron microscopic micrographs (SEM) were used to characterize surfaces of interest. RESULTS: Polished surfaces had significantly lower SBS (p < 0.05) compared with untreated specimens (AP vs AF). Silanated, non-polished surfaces (AF-s) revealed lower SBS, even though the result was not significantly different from that of AF-s without silane treatment. Plasma treatment improved SBS by a factor of 2 (p<0.05) and treatment with low-fusing porcelain micro pearls increased SBS by a factor of 3 compared to untreated surfaces (p<0.05). The layer of glass pearls did not exceed 5 microm (SEM). CONCLUSIONS: Within the limitation of the conditions of this study, treatment of alumina oxide ceramic surfaces with a plasma spray coating or a low-fusing porcelain pearl layer significantly increased the SBS of a resin luting agent to the ceramic surface.

  • 3. Derand, Tore
    et al.
    Molin, Margareta
    Umeå universitet, Medicinsk fakultet, Odontologi, Protetik.
    Kvam, Ketil
    Bond strength of composite luting cement to zirconia ceramic surfaces.2005Ingår i: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 21, nr 12, s. 1158-62Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 4.
    Dijken, Jan W.V. van
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Ardlin, Berit
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Tillberg, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Wahlin, Ylwa Britt
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Berglund, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Sunnegårdh-Grönberg, Karin
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Lindberg, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Molin, Margareta
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Sjögren, Göran
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Hulterström, Anna Karin
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Samarbete breddar forskning: Oral Biomaterialgruppen, Umeå2008Ingår i: Tandläkartidningen, Vol. 100, nr 5, s. 74-79Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

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

  • 5. Falk, Anders
    et al.
    von Steyern, Per Vult
    Franssori, Håkan
    Thoren, Margareta Molin
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Reliability of the Impression Replica Technique2015Ingår i: International Journal of Prosthodontics, ISSN 0893-2174, E-ISSN 1139-9791, Vol. 28, nr 2, s. 179-180Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aim of this study was to evaluate the reliability of the impression replica technique with a four-unit zirconia fixed dental prosthesis (FOP). Marginal and internal fit were measured by repeatedly placing the FDP on an epoxy cast using light-body silicone material corresponding to cement. All measured marginal and internal fit points showed varying values. The greatest variations were seen at the most distal margin (33 mu m) and at the distal abutment of the FDP (77 mu m). The results showed that the technique gives moderate variations and is a useful method to evaluate marginal and internal fit.

  • 6. Holm, Charlotta
    et al.
    Tidehag, Per
    Tillberg, Anders
    Molin, Margareta
    Umeå universitet, Medicinsk fakultet, Odontologi, Protetik. Umeå universitet, Medicinsk fakultet, Odontologi.
    Longevity and quality of FPDs: a retrospective study of restorations 30, 20, and 10 years after insertion.2003Ingår i: International Journal of Prosthodontics, ISSN 0893-2174, Vol. 16, nr 3, s. 283-9Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    PURPOSE: The aim of this retrospective study was to investigate the longevity and clinical performance of fixed partial dentures (FPD) 30, 20, and 10 years after insertion. MATERIALS AND METHODS: A total of 289 FPDs were inserted in 1966/67, 1976/77, and 1986/87. For patients with FPDs presumably still in function, an evaluation according to the CDA criteria was made. RESULTS: For 64 of the FPDs (22%), no information was available. Seventy-nine patients with 94 FPDs (33%) were clinically examined, and 44 of the FPDs (15%) were reported to be still in function by the patients' current clinicians. The remaining 87 FPDs (30%) were considered lost to follow-up. These FPDs had either been removed for various reasons--in most cases dental caries, lost retention, or fractured abutment teeth--or the patient could not be contacted. Eighty-four percent of the FPDs inserted in 1966/67 were still in function after 20 years, compared to 64% of those inserted in 1976/77. Apart from an increase in wear and discoloration, the oldest FPDs had excellent marginal fit and anatomic shape. CONCLUSION: The survival rate of 30-year-old FPDs was high; 53% remained in function after 30 years. Based on the CDA criteria, 78% of the restorations were rated satisfactory in all subgroups. The FPDs placed in 1966/67 obtained the highest ratings in color, anatomy, and margin integrity.

  • 7. Karlsson, Karolina
    et al.
    Derks, Jan
    Håkansson, Jan
    Wennström, Jan L.
    Molin Thorén, Margareta
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Petzold, Max
    Berglundh, Tord
    Technical complications following implant-supported restorative therapy performed in Sweden2018Ingår i: Clinical Oral Implants Research, ISSN 0905-7161, E-ISSN 1600-0501, Vol. 29, nr 6, s. 603-611Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Objective: The aim of this study was to evaluate the occurrence and consequences of technical complications in implant-supported restorative therapy.

    Material & Methods: The occurrence and consequences of technical complications in implant-supported restorative therapy over a mean follow-up period of 5.3years were assessed based on documentation in files from 2,666 patients. Risk indicators were identified by the use of survival models, considering repeated events. Results were expressed as hazard ratios (HR) including 95% confidence intervals.

    Results: Technical complications occurred in 24.8% of the patients. Chipping and loss of retention were the most common, affecting 11.0% and 7.9% of supraconstructions, respectively, while implant-related complications (e.g., implant fracture) were rare. More than 50% of the affected patients experienced technical complications more than once and almost all reported complications led to interventions by a dental professional. The extent of the supraconstruction was the strongest risk indicator for both chipping (HR<0.2) and loss of retention (HR>3).

    Conclusion: Over a 5-year period, technical complications in implant-supported restorative therapy occurred frequently and their management required professional intervention.

  • 8.
    Kou, Wen
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Gabrielsson, Klas
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Borhani, Adrian
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Carlborg, Markus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Molin Thorén, Margareta
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    The effect of artificial aging on high translucent zirconia2019Ingår i: Biomaterial Investigations in Dentistry, ISSN 2641-5275, Vol. 6, nr 1, s. 54-60Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Zirconia is known for its high strength but lacking translucency. Recently, a new type of high translucent zirconia, 5 mol% yttria partially stabilized zirconia (5Y-PSZ), with a larger fraction of cubic zirconia phase has become commercially available. However, the resistance to aging of these commercially available zirconia materials is not yet fully established.

    Purpose: The aim of the present study was to analyze the effects of artificial aging on surface roughness, transparency, phase transformation and biaxial flexural strength of two 5Y-PSZ products, DD cubeX2 and Prettau Anterior.

    Materials and methods: The artificial aging was performed in an autoclave under 2 bars of pressure at 134 °C for 10 hours, which is estimated to correspond to 30–40 years in vivo. Artificial aging for 10 hours had no significant effect on surface roughness, transparency, or phase transformation for either of the tested materials.

    Results: DD cubeX2 had higher mean flexural strength than Prettau Anterior both before and after artificial aging for 10 hours (p < .05). DD cubeX2 showed, however, a significant reduction in flexural strength after artificial aging (p < .05), whereas Prettau Anterior showed a slight increase in flexural strength after artificial aging but not at a significant level.

    Conclusion: Within the limitation of the present study, both DD cubeX2 and Prettau Anterior seems to be relatively resistant to aging. However, a wider range of measured flexural strength indicated that Prettau Anterior probably is a less stable material than DD cubeX2, which also means that the flexural strength of DD cubeX2 could be more predictable.

  • 9.
    Kou, Wen
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Odontologisk materialvetenskap.
    Molin, Margareta
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Protetik.
    Sjögren, Göran
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Odontologisk materialvetenskap.
    Surface roughness of five different dental ceramic core materials after grinding and polishing2006Ingår i: Journal of Oral Rehabilitation, ISSN 0305-182X, E-ISSN 1365-2842, Vol. 33, nr 2, s. 117-124Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In clinical practice, core materials can be exposed after adjustments are made to previously-luted all-ceramic restorations. The purpose of this study was to evaluate the surface roughness of five different dental ceramic core materials after grinding and polishing. Five different ceramic core materials, Vita In-Ceram Alumina, Vita In-Ceram Zirconia, IPS Empress 2, Procera AllCeram, and Denzir were evaluated. Vita Mark II was used as a reference material. The surface roughness, Ra value (mum), was registered using a profilometer. The measurements were made before and after grinding with diamond rotary cutting instruments and after polishing with the Sof-Lex system. The surface of representative specimens was evaluated qualitatively using scanning electron microscopy (SEM). Results were statistically analysed using analysis of variance (anova) supplemented with Scheffe's and Bonferroni multiple-comparison tests. Before grinding, Procera AllCeram and Denzir had the smoothest surfaces, while IPS Empress 2 had the coarsest. After grinding, all materials except IPS Empress 2 became coarser. Polishing with Sof-Lex provided no significant (P > 0.05) differences between Denzir, Vita Mark II and IPS Empress 2 or between Procera AllCeram and In-Ceram Zirconia. There were no significant differences (P > 0.05) either between the ground and the polished Procera AllCeram or In-Ceram Alumina specimens. Polishing of Denzir, IPS Empress 2 and In-Ceram Zirconia made the surfaces smoother compared with the state after grinding, whereas the polishing effect on Procera AllCeram and In-Ceram Alumina was ineffective. The findings of the SEM evaluation were consistent with the profilometer readings.

  • 10. Lundegren, Nina
    et al.
    Sohrabi, Melvin M.
    Molin Thorén, Margareta
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Akerman, Sigvard
    Prosthetic dental restorations in Swedish samples: prevalence and agreement between self-report, clinical findings, and influence on quality of life2019Ingår i: Acta Odontologica Scandinavica, ISSN 0001-6357, E-ISSN 1502-3850, Vol. 77, nr 4, s. 296-302Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Objective: To determine the prevalence of dental prosthetic restorations in an adult population, to study the agreement between self-reports and clinical findings of prosthetic restorations, and to study answers from a questionnaire in relation to the prevalence of prosthetic restorations. Material and methods: A questionnaire was sent to a sample of 10,000 adults. A further sample of 1000 individuals was invited to answer the questionnaire and also participate in a clinical study. The agreement between self-report and clinical findings was analyzed, as were the associations between prosthetic restorations and questionnaire responses, using the chi(2) test. Results: A total of 40% of the sample had fixed dental prostheses (FDP), 2.7% had removable dentures. The agreement between self-report and clinical findings was 93%. 34.7% of the individuals with no prosthetic restorations were university graduates and 4% of individuals with removable complete dentures. Oral health had the greatest impact on the quality of life of younger individuals with FDP, with an OHIP-14 (Oral Health Impact Profile) score of 7.3 for the age group 20-39 years compared to 4.9 for the age group 65-89 years. Conclusion: The questionnaire method can be a cost-effective way to determine the prevalence of prosthetic restorations.

  • 11.
    Molin, Margareta K
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Protetik.
    Karlsson, Stig L
    Five-year clinical prospective evaluation of zirconia-based Denzir 3-unit FPDs2008Ingår i: International Journal of Prosthodontics, ISSN 0893-2174, E-ISSN 1139-9791, Vol. 21, nr 3, s. 223-227Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Purpose: The aim of this prospective study was to evaluate the clinical performance of fully sintered hot isostatic pressed yttria-partially-stabilized zirconia (Denzir) 3-unit fixed partial dentures (FPDs).

    Materials and Methods: Nineteen 3-unit FPDs were placed in 18 patients. Ten FPDs were placed in the maxilla and 9 in the mandible. Two calibrated examiners evaluated the FPDs independently 1 week (baseline), 1 year, 3 years, and 5 years after placement using the California Dental Association quality evaluation system.

    Results: All FPDs were intact at the 5-year examination. One FPD lost retention after 12 months but remained intact; it was recemented and is still in function after 5 years. All FPDs were rated satisfactory over 5 years. No changes were seen in terms of color and anatomic form. The number of slightly rough or pitted occlusal surfaces increased approximately 30% over 5 years. Visible evidence of ditching along the margin increased over time, but only for those FPDs luted with zinc phosphate cement.

    Conclusion: The 5-year results indicate that yttria-partially-stabilized zirconia 3-unit FPDs with anatomically designed frameworks are promising prosthetic alternatives, even in the premolar and molar regions. However, for all-ceramic FPDs with more units in function, further studies are necessary.

  • 12.
    Molin, Margareta
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Protetik.
    Onesti, MP
    Pettersson, TB
    Dérand, TB
    Three-dimensional finite element analyses of all-ceramic posterior fixed partial dentures with different designs.2007Ingår i: The International Journal of Prosthodontics, Vol. 20, nr 1, s. 89-91Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aim was to evaluate the influence on the stress distribution patterns in and the magnitude of stresses on fixed partial dentures (FPDs) under different anatomic and design conditions. Three-dimensional finite element models of posterior 3-unit all-ceramic FPDs were created with and without periodontal ligaments, with different radii of curvature at the embrasure area, and in a curve shape with a periodontal ligament. The model with a periodontal ligament showed 40% higher stress values compared to the no-ligament model. A smaller radius of curvature resulted in 20% to 40% higher stress values. The curved model increased stress values at the distal connector by 65% compared to the straight model. Support by teeth, occlusal curvature, and a small radius of curvature at the embrasure area negatively affect stress distribution patterns in the connector area of all-ceramic FPDs.

  • 13.
    Pettersson, Mattias
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Kelk, Peyman
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Belibasakis, G. N.
    University of Zurich.
    Bylund, D.
    Mittuniversitetet Sundsvall.
    Molin Thorén, Margareta
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Johansson, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Titanium ions form particles that activate and execute interleukin-1β release from lipopolysaccharide-primed macrophages2017Ingår i: Journal of Periodontal Research, ISSN 0022-3484, E-ISSN 1600-0765, Vol. 52, nr 1, s. 21-32Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND AND OBJECTIVE: Peri-implantitis is a destructive inflammatory process characterized by destruction of the implant-supporting bone. Inflammasomes are large intracellular multiprotein complexes that play a central role in innate immunity by activating the release of proinflammatory cytokines. Although inflammasome activation has previously been linked to periodontal inflammation, there is still no information on a potential association with peri-implantitis. The aim of this study was to examine cytotoxic and proinflammatory effects, including inflammasome activation, of metals used in dental implants, in an in vitro model, as well as from clinical tissue samples.

    MATERIAL AND METHODS: Human macrophages were exposed to different metals [titanium (Ti), cobalt, chromium and molybdenum] in a cell-culture assay. Cytotoxicity was determined using the neutral red uptake assay. Cytokine secretion was quantified using an ELISA, and the expression of genes of various inflammasome components was analysed using quantitative PCR. In addition, the concentrations of interleukin-1β (IL-1β) and Ti in mucosal tissue samples taken in the vicinity of dental implants were determined using ELISA and inductively coupled plasma mass spectrometry, respectively.

    RESULTS: Ti ions in physiological solutions stimulated inflammasome activation in human macrophages and consequently IL-1β release. This effect was further enhanced by macrophages that have been exposed to lipopolysaccharides. The proinflammatory activation caused by Ti ions disappeared after filtration (0.22 μm), which indicates an effect of particles. Ti ions alone did not stimulate transcription of the inflammasome components. The Ti levels of tissue samples obtained in the vicinity of Ti implants were sufficiently high (≥ 40 μm) to stimulate secretion of IL-1β from human macrophages in vitro.

    CONCLUSION: Ti ions form particles that act as secondary stimuli for a proinflammatory reaction.

  • 14.
    Pettersson, Mattias
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Pettersson, Jean
    Department of Chemistry - BMC, Analytical Chemistry, Uppsala, University.
    Johansson, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Molin Thorén, Margareta
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Titanium release in peri-implantitis2019Ingår i: Journal of Oral Rehabilitation, ISSN 0305-182X, E-ISSN 1365-2842, Vol. 46, nr 2, s. 179-188Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Objectives: The aim of this study was to investigate the titanium (Ti) content of biopsies from patients with severe peri-implantitis or periodontitis and to examine whether Ti particles can be identified in samples from peri-implantitis lesions.

    Background: Long-term follow-up studies show that implant usage to replace missing or lost teeth is a safe and predictable treatment. However, inflammation and loss of supporting bone around an implant (peri-implantitis) lead to patient suffering and costs. Peri-implantitis is considered to be an infectious disease, but recent studies have shown that Ti can aggravate inflammation in combination with bacterial products. The Ti content of peri-implantitis and periodontitis tissue is unknown.

    Methods: Thirteen patients referred for peri-implantitis and eleven for periodontitis treatment were included in the study. Disease severity was obtained from dental records. Biopsies were taken from both groups and chemically analyzed with inductively coupled plasma mass spectrometry (ICP-MS) for Ti content. Additionally, two patients with peri-implantitis and two with periodontitis were recruited and their biopsies were analyzed microscopically with light microscopy (LM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) with element analysis to investigate the presence of particulate Ti.

    Results: All patients lost one or more implants despite undergoing peri-implant or periodontal treatment. Peri-implantitis tissue contained significantly higher concentrations of Ti than periodontitis tissue with a mean ± SDof 98.7 ± 85.6 μg/g and 1.2 ± 0.9 μg/g, respectively. Particulate metal was identified in peri-implantitis and periodontitis biopsies, but element analyses could confirm only the presence of Ti in peri-implantitis tissue. The mean size ± SDof the visible particles with LM was 10.9 ± 35.7 μm2 (mean of three repeated measurements) (95% CI, 6.5-15.3).

    Conclusion: We showed that high contents of particulate and submicron Ti were present in peri-implantitis tissue. These high Ti contents in peri-implant mucosa can potentially aggravate inflammation, which might reduce the prognosis of treatment interventions.

  • 15.
    Pettersson, Mattias
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Tandläkarutbildning.
    Pettersson, Jean
    Department of Chemistry - BMC, Analytical Chemistry, Uppsala, University.
    Molin Thorén, Margareta
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Johansson, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Effect of cobalt ions on the interaction between macrophages and titanium2018Ingår i: Journal of Biomedical Materials Research. Part A, ISSN 1549-3296, E-ISSN 1552-4965, nr 9, s. 2518-2530Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Inflammation and bone reduction around dental implants are described as periimplantitis and can be caused by an inflammatory response against bacterial products and toxins. Titanium (Ti) forms aggregates with serum proteins, which activate and cause release of the cytokine interleukin (IL-1β) from human macrophages. It was hypothesized that cobalt (Co) ions can interact in the formation of pro-inflammatory aggregates, formed by titanium. To test this hypothesis, we differentiated THP-1 cells into macrophages and exposed them to Ti ions alone or in combination with Co ions to investigate if IL-1β release and cytotoxicity were affected. We also investigated aggregate formation, cell uptake and human biopsies with inductively coupled plasma atomic emission spectroscopy (ICP-AES) and electron microscopy. Co at a concentration of 100 μM neutralized the IL-1β release from human macrophages and affected the aggregate formation. The aggregates formed by Ti could be detected in the cytosol of macrophages. In the presence of Co, the Ti-induced aggregates were located in the cytosol of the cultured macrophages, but outside the lysosomal structures. It is concluded that Co can neutralize the Ti-induced activation and release of active IL-1β from human macrophages in vitro. Also, serum proteins are needed for the formation of metal-protein aggregates in cell medium. Furthermore, the structures of the aggregates as well as the localization after cellular uptake differ if Co is present in a Ti solution. Phagocytized aggregates with a similar appearance seen in vitro with Ti present, were also visible in a sample from human peri-implant tissue.

  • 16.
    Pettersson, Mattias
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Pettersson, Jean
    Analytic Chemistry, BMC, Department of Chemistry, Uppsala University, Sweden.
    Molin Thorén, Margareta
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Johansson, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Release of titanium after insertion of dental implants with different surface characteristics: an ex vivo animal study2017Ingår i: Acta Biomaterialia Odontologica Scandinavica, ISSN 0001-5369, E-ISSN 2333-7931, Vol. 3, nr 1, s. 63-73Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the present study, amount of titanium (Ti) released into the surrounding bone during placement of implants with different surface structure was investigated. Quantification of Ti released during insertion from three different implants was performed in this ex vivo study. Jaw bone from pigs was used as model for installation of the implants and Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) was used for analysis of the released Ti. Implant surface were examined with scanning electron microscopy (SEM), before and after the placement into the bone. Ti was abraded to the surrounding bone upon insertion of a dental implant and the surface roughness of the implant increased the amount of Ti found. Diameter and total area of the implant were of less importance for the Ti released to the bone. No visible damages to the implant surfaces could be identified in SEM after placement.

  • 17.
    Sjögren, Göran
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Odont materialvetenskap.
    Molin, Margareta
    Umeå universitet, Medicinsk fakultet, Odontologi, Odont materialvetenskap.
    van Dijken, Jan
    Umeå universitet, Medicinsk fakultet, Odontologi, Odont materialvetenskap.
    A 10-year prospective evaluation of CAD/CAM-manufactured (Cerec) ceramic inlays cemented with a chemically cured or dual-cured resin composite2004Ingår i: International Journal of Prosthodontics, ISSN 0893-2174, E-ISSN 1139-9791, Vol. 17, nr 2, s. 241-246Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    PURPOSE: The present follow-up study was carried out to evaluate the performance of Class II Cerec inlays after 10 years of clinical service. MATERIALS AND METHODS: Sixty-six Class II CAD/CAM ceramic inlays were placed in 27 patients. Each patient received at least one inlay luted with a dual-cured resin composite and one inlay luted with a chemically cured resin composite. At the 10-year recall, 25 (93%) patients with 61 (92%) inlays were available for evaluation using a slight modification of the USPHS criteria. RESULTS: Fifty-four (89%) of the 61 inlays reevaluated still functioned well at the 10-year recall. During the follow-up period, seven (11%) of the inlays required replacement because of: four inlay fractures, one cusp fracture, endodontic problems in one case, and postoperative symptoms in one case. All the replaced inlays had been luted with the dual-cured resin composite. The fractured inlays were all placed in molars. The estimated survival rate after 10 years was 89%, 77% for the dual-cured resin composite-luted inlays and 100% for the chemically cured resin composite-luted ones. The difference was statistically significant. CONCLUSION: Patient satisfaction with and acceptance of the Cerec inlays were high, and the performance after 10 years of clinical service was acceptable, especially regarding the inlays luted with the chemically cured resin composite. The properties of the luting agents seem to affect the longevity of the type of ceramic inlays evaluated.

  • 18.
    Sundh, Anders
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Molin, Margareta
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Protetik.
    Sjögren, Göran
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Odontologisk materialvetenskap.
    Fracture resistance of yttrium oxide partially-stabilized zirconia all-ceramic bridges after veneering and mechanical fatigue testing2005Ingår i: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 21, nr 5, s. 476-482Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    OBJECTIVES: Yttria-stabilized zirconia (Y-TZP) ceramic is a high-performance material with excellent mechanical properties suitable for fixed partial dentures. The purpose of this study was to evaluate after fatigue testing, the effect of heat-treatment and veneering on the fracture resistance of frameworks manufactured using sintered and subsequently hot isostatic pressed yttrium oxide partially-stabilized zirconia (Denzir).

    METHODS: The specimens were subjected to dynamic loading in water. Thereafter, using a universal testing machine, the fracture resistance of three-unit fixed partial dentures was determined; (i) of the frameworks as delivered after machining, (ii) after the frameworks had been subjected to heat-treatment similar to veneering with a glass-ceramic (Eris) or a feldspar-based ceramic (Vita D) and (iii) after the frameworks had been veneered with these ceramics. In addition, the fracture resistance of frameworks as delivered after machining not subjected to dynamic loading in water was determined.

    RESULTS: Cyclic loading in water did not significantly (p>0.05) affect the fracture resistance. The load necessary to fracture the frameworks as delivered after machining was significantly (p<0.001) higher than for the heat-treated and veneered specimens. No significant difference was seen between the specimens veneered with Eris and those veneered with Vita D (p>0.05). For all but three specimens the fractures were located in the loading point and through one of the connectors.

    SIGNIFICANCE: Heat-treatment and veneering reduce fracture resistance of hot isostatic pressed zirconia. Nevertheless, the results obtained indicate that it is an interesting material for potential in all-ceramic restorations.

  • 19. Ågren, Martin
    et al.
    Kou, Wen
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Molin Thorén, Margareta
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Bond strength of surface-treated novel high translucent zirconia to enamel2019Ingår i: Biomaterial Investigations in Dentistry, Vol. 6, nr 1, s. 35-42Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Aim: The aim of the present study was to evaluate the shear bond strength of zirconia, stabilised with 5% yttria, luted to enamel and to evaluate the fracture pattern at loss of retention.

    Methods: A total of 53 test specimen were manufactured from two partially stabilised zirconia materials, Zirkonzahn Prettau Anterior (ZPA) (n = 16) and Whitepeaks CopraSmile Symphony 5 layer (WCS) (n = 18), and a lithium disilicate (Ivoclar e.Max Press) (n = 19) acting as control. All test specimens were cemented to human enamel with Variolink Esthetic DC and then subjected to a shear bond strength test. Fracture and surface analysis were performed using light and scanning electron microscope.

    Results: No significant differences in shear bond strength were detected when analysing the three groups. Dividing them according to the fracture pattern significant difference in shear bond strength between the two zirconia groups could be seen analysing test bodies with failure of adhesion to the test body, but not to enamel. The ZPA had higher shear bond strength (23.68 MPa) than WCS (13.00 MPa). No significant differences were seen compared to the control group (19.02 MPa).

    Conclusion: Partially stabilised zirconia shows potential as a material to be used where macro mechanical bonding is not possible, although this study does not reveal how or if the bonding deteriorates over time.

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