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  • 1. Berglund, A
    et al.
    Molin, M
    Umeå University, Faculty of Medicine, Odontology, Prosthetic Dentistry.
    Mercury levels in plasma and urine after removal of all amalgam restorations: the effect of using rubber dams.1997In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 13, no 5, p. 297-304Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: The aim of the present study was to determine whether removal of all amalgam restorations might significantly affect mercury levels in plasma and urine and whether the use of rubber dams might reduce patient exposure to mercury during amalgam removal. METHODS: All amalgam restorations were removed from 18 subjects during a single treatment session in which a rubber dam was used and from 10 subjects when a rubber dam was not used. All amalgam restorations were removed by the same dentist using high-speed cutting, water coolant, and high-volume evacuation. The levels of mercury in plasma and urine were analyzed both before and during the subsequent twelve months after amalgam removal. In order to determine whether removal of all amalgam restorations might cause an exposure large enough to significantly increase the mercury levels in two indicator media for mercury exposure, i.e., plasma and urine, and to determine if the removal might cause a significant decrease in the mercury levels found over time, the one-tailed, paired Students' t-test was used. For each individual, the pre-removal levels were compared with both the levels found in plasma on d 1 and in urine on d 10, and also with the levels found 1 y after removal. Furthermore, in order to examine whether the use of rubber dams had any effect on the mercury levels found after removal, the changes in the mercury levels found were compared between the groups using the Wilcoxon-Mann-Whitney rank sum test. RESULTS: After removal of all amalgam restorations, only the non-rubber dam group showed significant increases in the mercury levels found in plasma (p = 0.012) and urine (p = 0.037). However, one year later, the mercury levels in plasma and urine had sunk significantly below the pre-removal levels for both groups. When the changes in the mercury levels found were compared between the groups, the non-rubber dam group showed a significantly higher increase of mercury in plasma than the rubber dam group the day after removal (p = 0.0010). Compared to the pre-removal mercury levels in plasma and urine, the levels found 1 y after removal of all amalgam restorations were on average 52 +/- 23% (range 4-89%) lower in plasma and 76 +/- 21% (range 20-94%) lower in urine. SIGNIFICANCE: The study showed that dental amalgam had a statistically significant impact on the mercury levels found in plasma and urine in the patients tested, and that the use of a rubber dam during removal of all amalgam restorations significantly reduced the peak of mercury in plasma following removal.

  • 2.
    Berglund, Anders
    et al.
    Umeå University, Faculty of Medicine, Odontology, Dental Technology/Dental Materials Science.
    Hulterström, Anna Karin
    Umeå University, Faculty of Medicine, Odontology, Dental Technology/Dental Materials Science.
    Gruffman, Ewa
    Umeå University, Faculty of Medicine, Odontology, Dental Materials Science.
    van Dijken, Jan
    Umeå University, Faculty of Medicine, Odontology, Dental Hygiene.
    Dimensional change of a calcium aluminate cement for posterior restorations in aqueous and dry media.2006In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 22, no 5, p. 470-476Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: A calcium aluminate cement has recently been developed, with claims of being an alternative to dental amalgam and resin composites in posterior cavities. However, its' mechanical properties are not well evaluated and the aim of the study was therefore, to evaluate its' dimensional stability over time. METHODS: The dimensional changes of the cement, Doxadent, and two composite resins, Esthet-X and InTen-S, were tested during 360 d. The specimens were stored at 37+/-1 degrees C either in 100% air humidity (dry) or immersed in distilled water (wet), except for the first 24h when all specimens were stored at 100% air humidity and 37+/-1 degrees C. RESULTS: During the first 24h, Doxadent decreased in volume with 0.04%, while InTen-S and Esthet-X decreased with 1.60 and 1.75%, respectively. From d 1-360, the dry Doxadent specimens increased in volume with 2.0% and in weight with 5.5%, while the corresponding increase for the wet specimens were 4.1 and 6.3%, respectively. The volume of both composites increased 0.8% or less in dry and wet conditions, while the increase in weight for InTen-S was 1.2% for the wet specimens and 0.6% for the dry. The corresponding figures for Esthet-X were 0.7 and 0.2%. SIGNIFICANCE: Doxadent was less dimensionally stable than the composites tested. Doxadent increased 2 times more in volume immersed in water than in 100% air humidity, while the increase in weight was almost similar. The clinical implications of the results found in the present study are uncertain. A material that continues to absorb water during prolonged periods and continues to react is questionable for clinical use.

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

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

  • 4.
    Håff, Anna
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Dental Materials Science.
    Löf, Hanna
    Umeå University, Faculty of Medicine, Department of Odontology, Dental Materials Science.
    Gunne, Johan
    Umeå University, Faculty of Medicine, Department of Odontology, Prosthetic Dentistry.
    Sjögren, Göran
    Umeå University, Faculty of Medicine, Department of Odontology, Dental Materials Science.
    A retrospective evaluation of zirconia-fixed partial dentures in general practices: an up to 13-year study2015In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 31, no 2, p. 162-170Article in journal (Refereed)
    Abstract [en]

    Objectives: To evaluate zirconia-based fixed partial dentures (FPDs) after more than 8 years in clinical service.

    Methods: Patients treated between 2000 and 2004 with zirconia FPDs were identified from the records of a manufacturer of FPD substructures. Of the 45 patients who met the inclusion criteria 30 attended the appointment and 33 FPDs were evaluated using modified California Dental Association (CDA) criteria. In addition, plaque and the bleeding index were registered. Patient satisfaction with the restorations was evaluated using a 10-point visual analog scale (VAS).

    Results: All the FPDs were made using CAD/CAM and hot isostatic pressed yttria-tetragonal zirconia polycrystal (HIPed Y-TZP) ceramic (Denzir) and were placed within general practices. The mean observation period was 9.6 ± 1.6 years (range 3.0–13.1 years). The CDA rating was 90% satisfactory for the surface. Corresponding figures for anatomic form, color and margin integrity were 94%, 100% and 94%, respectively. Regarding surface three (9.7%) FPDs exhibited veneer chipping and were rated ‘not acceptable’. For margin integrity two (6.5%) were rated ‘not acceptable’ because of caries. For anatomic form two (6.1%) were rated ‘not acceptable’ due to two lost FPDs. No significant differences were seen between the FPDs and controls for plaque and bleeding. The Kaplan–Meier survival rate (still in clinical function) was 94%, the success rate (technical events accounted for) 91% and (biological events accounted for) 73%. Based on the VAS the mean value for patient satisfaction was 9.3 ± 1.2.

    Significance: Ninety-four percent of the FPDs were still in clinical function. HIPed Y-TZP could serve as an alternative for FPD treatments similar to those in the current study.

  • 5.
    Kou, Wen
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Dental Materials Science. Umeå University, Faculty of Medicine, Department of Odontology.
    Kou, Shaoquan
    Department of Civil and Mining Engineering, Luleå University of Technology, Luleå, Sweden.
    Liu, Hongyuan
    Department of Civil and Mining Engineering, Luleå University of Technology, Luleå, Sweden.
    Sjögren, Göran
    Umeå University, Faculty of Medicine, Department of Odontology, Dental Materials Science.
    Numerical modeling of the fracture process in a three-unit all-ceramic fixed partial denture2007In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 23, no 8, p. 1042-1049Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: The main objectives were to examine the fracture mechanism and process of a ceramic fixed partial denture (FPD) framework under simulated mechanical loading using a recently developed numerical modeling code, the R-T(2D) code, and also to evaluate the suitability of R-T(2D) code as a tool for this purpose. METHODS: Using the recently developed R-T(2D) code the fracture mechanism and process of a 3U yttria-tetragonal zirconia polycrystal ceramic (Y-TZP) FPD framework was simulated under static loading. In addition, the fracture pattern obtained using the numerical simulation was compared with the fracture pattern obtained in a previous laboratory test. RESULTS: The result revealed that the framework fracture pattern obtained using the numerical simulation agreed with that observed in a previous laboratory test. Quasi-photoelastic stress fringe pattern and acoustic emission showed that the fracture mechanism was tensile failure and that the crack started at the lower boundary of the framework. The fracture process could be followed both in step-by-step and step-in-step. SIGNIFICANCE: Based on the findings in the current study, the R-T(2D) code seems suitable for use as a complement to other tests and clinical observations in studying stress distribution, fracture mechanism and fracture processes in ceramic FPD frameworks.

  • 6. Pallesen, Ulla
    et al.
    van Dijken, Jan W V
    Umeå University, Faculty of Medicine, Department of Odontology.
    A randomized controlled 30 years follow up of three conventional resin composites in Class II restorations2015In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 31, no 10, p. 1232-1244Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: The aim of this 30 year randomized controlled study was to evaluate, by intraindividual comparisons, the durability of three conventional resin composites in Class II restorations.

    METHODS: Each of 30 participants, 21 female and 9 male (mean age 30 years, range 20-43), received at least three (one set) as similar as possible Class II restorations of moderate size. After cavity preparation, the three cavities were chosen at random to be restored with two chemical-cured (P10, Miradapt) and one light-cured resin composite (P30). A chemical-cured enamel bonding agent was applied after etching of the enamel. The chemical-cured resin composites were placed in bulk and the light-cured in increments. One operator placed 99 restorations (33 sets). The restorations were evaluated with slightly modified USPHS criteria at baseline, 2, 3, 5, 10, 15, 20 and 30 years. Statistical analyses were performed by the Kaplan-Meier, log-rank test and Cox regression analyses.

    RESULTS: After 30 years, 5 participants with 15 restorations (15%) could not be evaluated during the whole evaluation. Seven participants were considered as caries risk and eight participants as having active parafunctional habits. Postoperative sensitivity was observed in 24 teeth. In total 28 restorations, 9 P10, 12 P30 and 7 Miradapt restorations failed during the 30 years. The main reasons for failure were secondary caries (39.2%) and material fracture (35.7%). Sixty-four percent of the secondary caries lesions were found in high caries risk participants and 70% of the material fractures occurred in participants with active parafunctional habits. The overall success rate at 30 years was 63%, with an annual failure rate of 1.1%. 68-81% of the restorations showed non-acceptable color match. No statistical significant difference in survival rate was found between the three resin composites (p=0.45). The variables tooth type, cavity size, age, and gender of the participants did not significantly affect the probability of failure.

    SIGNIFICANCE: The three conventional resin composites showed good clinical performance during the 30 year evaluation. The chemical cured resin composites showed better performance than the light-cured composite.

  • 7.
    Persson-Sjögren, Solveig
    et al.
    Umeå University, Faculty of Medicine, Integrative Medical Biology.
    Sjögren, Göran
    Umeå University, Faculty of Medicine, Odontology, Dental Materials Science.
    Effects of dental materials on insulin release from isolated islets of Langerhans2002In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 18, no 1, p. 20-25Article in journal (Refereed)
    Abstract [en]

    Objectives: To investigate the possibility of using a whole organ model for evaluating the biological effects of dental restoration materials in vitro.

    Methods: The effect on insulin release of isolated Langerhans islets of a series of dental materials was examined. The islets were incubated for 1 h with extracts obtained from various dental materials and insulin was assayed radioimmunologically with crystalline mouse insulin. The results were analysed statistically using analysis of variance (ANOVA) and Scheffe's test at a significance level of p<0.05.

    Results: One dental ceramic, Vita VMK 95, significantly ( p<0.01) decreased the insulin release, whereas another dental ceramic, Empress ( p<0.01), a partly re-cast high-noble gold alloy ( p<0.001), a modified high-noble gold alloy ( p<0,05), and unalloyed copper ( p<0.001) significantly increased the release of insulin.

    Significance: The results demonstrate a new instance of examining the biological effects of dental restoration materials. The method provides information about the effect of different materials on organ level in vitro that can complement other in vitro tests.

  • 8.
    Sahlin-Platt, Annika
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Oral Cell Biology.
    Örtengren, Ulf
    Mladenovic, Zivko
    Umeå University, Faculty of Medicine, Department of Odontology, Oral Cell Biology.
    Ransjö, Maria
    Umeå University, Faculty of Medicine, Department of Odontology, Oral Cell Biology.
    Effects of Dyract AP and released ionic products on periodontal ligament cells and bone marrow cultures2008In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 24, no 12, p. 1623-1630Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: The aim of this work was to investigate the release of inorganic ionic products from specimens of the polyacid-modified composite resin Dyract AP (DAP) and furthermore, to analyze the biological effect of DAP and the medium extract in human periodontal ligament (PDL) cells and mouse bone marrow cell (BMC) cultures.

    METHODS: Ion release from DAP specimens immersed in cell culture medium was analyzed with inductively coupled plasma optical emission spectroscopy (ICP-OES). Cells were cultured with either DAP specimens or with DAP media extract and effects on cell proliferation, osteoblastic gene expression and mineralization capacity were analyzed with direct-contact tests, neutral red (NR) uptake, quantitative real-time PCR and a bone nodule formation assay.

    RESULTS: ICP-OES analysis of DAP extract demonstrated a significant increase in fluoride, strontium and silica. PDL cells demonstrated normal growth pattern in the direct-contact tests with the material. DAP extracts produced a dose-dependent stimulation of cell proliferation and concomitant inhibition of osteoblast specific markers and nodule formation.

    SIGNIFICANCE: The compomer may have possible bioactive properties due to ions leaching out from the filler component.

  • 9.
    Sundh, Anders
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Molin, Margareta
    Umeå University, Faculty of Medicine, Department of Odontology, Prosthetic Dentistry.
    Sjögren, Göran
    Umeå University, Faculty of Medicine, Department of Odontology, Dental Materials Science.
    Fracture resistance of yttrium oxide partially-stabilized zirconia all-ceramic bridges after veneering and mechanical fatigue testing2005In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 21, no 5, p. 476-482Article in journal (Refereed)
    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.

  • 10.
    Sundh, Anders
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Dental Materials Science.
    Sjögren, Göran
    Umeå University, Faculty of Medicine, Department of Odontology, Dental Materials Science.
    A study of the bending resistance of implant-supported reinforced alumina and machined zirconia abutments and copies2008In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 24, no 5, p. 611-617Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: The purpose of the present study was to evaluate the bending resistance of implant-supported CAD/CAM-processed restorations made out of zirconia or manually shaped made out of reinforced alumina.

    METHODS: Units of abutments and copies made of (i) a prefabricated hot isostatic pressed (HIPed) yttrium oxide partially-stabilized zirconia (Y-TZP) (Denzir), (ii) a prefabricated densely-sintered magnesia partially stabilized zirconia (Mg-PSZ) (Denzir-M) or, copies made of (iii) a prefabricated partially-sintered, porous reinforced alumina ceramic (RN synOcta-In-Ceram) were subjected to static loading perpendicularly at the long axis. The abutments were attached to either stainless steel analogs or titanium implant fixtures. The Y-TZP and Mg-PSZ copies were bonded onto the ceramic abutments with a dual-cured resin composite (Rely-X Unicem). Units of titanium abutment attached to a titanium implant fixtures were used as reference.

    RESULTS: The units comprising Denzir abutments as delivered (p<0.05) and heat-treated Denzir copies bonded to the Denzir abutments as delivered (p<0.01) and attached to stainless steel analogs exhibited significantly higher bending resistance than the control. The heat-treated Denzir copies bonded to the heat-treated Denzir M abutments attached to titanium implant fixtures and the In-Ceram specimens attached to stainless steel analogs showed significantly (p<0.05) lower bending resistance than the heat-treated Denzir copies bonded to the Denzir abutments as delivered and attached to stainless steel analogs. No statistically significant (p>0.05) differences were seen among the other groups studied.

    SIGNIFICANCE: All the ceramic abutments and copies exhibited values that were equal or superior to that of the control and exceeded the reported value, up to 300 N, for maximum incisal bite forces. To assess the clinical behavior long-term clinical studies should be conducted.

  • 11.
    Sundh, Anders
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Dental Materials Science.
    Sjögren, Göran
    Umeå University, Faculty of Medicine, Department of Odontology, Dental Materials Science.
    Fracture resistance of all-ceramic zirconia bridges with differing phase stabilizers and quality of sintering2006In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 22, no 8, p. 778-784Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: The mechanical properties of zirconia ceramics are affected of stabilizing oxides and quality of sintering. The purpose of this study was to investigate the fracture resistance of frameworks manufactured using prefabricated zirconia blanks with differing stabilizing oxides and quality of sintering.

    METHODS: After dynamic loading in water, the fracture resistance was determined of stylized three-unit fixed partial dentures made of prefabricated homogenous ceramic green-body yttria-stabilized zirconia (Y-TZP) blanks (Vita YZ) or of densely-sintered magnesia partially stabilized zirconia (Mg-PSZ) blanks (Denzir-M); (i) as supplied from the manufacturer, (ii) after subjection to heat treatment in a way similar to veneering, and (Hi) after veneering with a feldspar-based ceramic.

    RESULTS: After veneering, the load at fracture of the Vita YZ specimens was significantly higher (p<0.05) than that of Denzir-M. The load necessary to fracture Denzir-M as supplied after machining was significantly (p<0.05) higher than that of heat-treated Denzir-M, Vita YZ as supplied and heat-treated Vita YZ specimens. There was no significant difference (p>0.05) between the heat-treated and veneered Denzir-M specimens. For Vita YZ the load at fracture of the veneered specimens was significantly (p<0.05) higher than of those as supplied or heat-treated, whereas no significant difference (p>0.05) was seen between heat-treated Vita YZ and Vita YZ specimens as supplied.

    SIGNIFICANCE: The fracture strength of the Vita YZ specimens increased considerably after veneering. Denzir-M and Vita YZ seem to be interesting alternatives for use as core materials in all-ceramic restorations. Long-term studies are, however, necessary before general clinical recommendations can be issued.

  • 12.
    Tillberg, Anders
    et al.
    Umeå University, Faculty of Medicine, Odontology, Dental Materials Science.
    Järvholm, Bengt
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Berglund, Anders
    Umeå University, Faculty of Medicine, Odontology, Dental Technology/Dental Materials Science.
    Risks with dental materials2008In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 24, no 7, p. 940-943Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: Dental materials are among the most used substitutes for biological tissue in the human body. The possible health effects of amalgam have been studied extensively and have sometimes been replaced with other less well-examined materials. The aim was to study the hazards of other dental materials than amalgam. METHODS: Toxicological information was collected from the Swedish Dental Materials Register 2003 (DentMr). The material safety data sheets (MSDS) included in the DentMR was examined regarding the given composition of the products, the occurrence of CAS-numbers and risk and safety phrases of the substances. Furthermore, complementary information about risk and safety phrases for substances with missing information in the MSDS was collected by using two easily available databases. RESULTS: There were 482 products that included 377 substances of which 219 could be identified. Only 26% of 219 substances had risk and safety phrases. However, via the Swedish Chemicals Inspectorate Classification Register and the Sigma-Aldrich product register, risk and safety phrases could be found for 37 substances. A literature search indicated that some of the listed substances had possible hazards, e.g. substances with embryotoxic and neurotoxic potential. SIGNIFICANCE: The information about hazards with dental materials seems insufficiently described in MSDS and there might be materials with side effects unknown to both patients and dental personnel. There is a need for stronger regulation of dental materials, at least substances that the patients will be exposed to for decades.

  • 13.
    Uo, Motohiro
    et al.
    Umeå University, Faculty of Medicine, Odontology, Dental Materials Science.
    Sjögren, Göran
    Umeå University, Faculty of Medicine, Odontology, Dental Materials Science.
    Sundh, Anders
    Watari, Fumio
    Bergman, Maud
    Lerner, Ulf
    Umeå University, Faculty of Medicine, Odontology, Oral Cell Biology.
    Cytotoxicity and bonding property of dental ceramics.2003In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 19, no 6, p. 487-92Article in journal (Refereed)
    Abstract [en]

    Objectives . Yttria partially stabilized zirconia (YPSZ) ceramic is suitable for dental and medical use because of its high fracture toughness and chemical durability. The purpose of this study was to estimate the cytotoxicity and bonding property of zirconia ceramic compared to other dental ceramics.

    Methods . Eight commercial dental ceramics including Denzir (YPSZ) are used in this cytotoxicity test. The human gingival fibroblast (GF) cells were cultured using extraction solutions of ceramics. The cytotoxicity was estimated by two different methods. The bonding strength of Denzir was compared to Empress2 using zinc phosphate, glass ionomer, and adhesive resin cements. A brass plate was prepared with drilled tapered holes and ceramic specimens were prepared to fit the holes and bonded. The bonding strength was estimated by the punching test.

    Results . No significant ( p>0.05) cytotoxicity was observed in all ceramic extractions. The two evaluation methods showed no significant differences. Denzir and Empress2 showed similar bonding strength with zinc phosphate or glass ionomer cement bonding. For both Empress2 and Denzir the glass ionomer cement showed significantly ( p<0.001) higher bonding strength compared to the zinc phosphate cement. Empress2 showed significantly higher bonding strength with adhesive resin cement. However, the Denzir showed lower bonding strength with adhesive resin cement.

    Significance . No ceramic extractions showed any evidence of cytotoxicity. Therefore, the low in vitro cytotoxicity of ceramic extractions including Denzir was confirmed. Denzir showed a similar bonding strength to Empress2 with zinc phosphate or glass ionomer cement bonding with this testing method and lower bonding strength with adhesive resin cement than with Empress2.

  • 14.
    van Dijken, Jan
    Umeå University, Faculty of Medicine, Odontology, Dental Hygiene.
    A 6-year clinical evaluation of Class I poly-acid modified resin composite/resin composite laminate restorations cured with a two-step curing technique.2003In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 19, no 5, p. 423-428Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: Polymerization shrinkage is still one of the main disadvantages of resin composite restorations (RC). Especially in cavities with a high C-factor, debonding can occur. A laminate restoration including a base with a more elastic behavior might result in a better adaptation. The purpose of this study was to evaluate the durability of a combination of two techniques suggested to counter the stress formation in direct RC restorations in cavities with the highest C-factor. METHODS: Each of the 29 patients received one or two pair(s) of Class I restorations. The first restoration was a poly-acid modified resin composite/resin composite (PMRC/RC) sandwich restoration and the second a direct RC restoration. Both restorations, except for the PMRC layer, were placed with oblique layering and two-step curing technique. Ninety restorations, 23 premolar and 67 molars, were evaluated annually with slightly modified USPHS criteria during 6 years. RESULTS: At 6 years, 41 pairs were evaluated. A cumulative failure rate of 2.4% was observed for both the RC and the laminate restorations. One laminate restoration showed non-acceptable color match, but was not replaced and one RC restoration showed non-acceptable marginal adaptation. Two cases of slight postoperative sensitivity were observed in one patient. Three restorations were partially replaced due to primary proximal caries. SIGNIFICANCE: A high durability for and no differences, were observed between both restorative techniques in Class I cavities.

  • 15.
    van Dijken, Jan
    Umeå University, Faculty of Medicine, Odontology, Dental Hygiene.
    Resin-modified glass ionomer cement and self-cured resin composite luted ceramic inlays. A 5-year clinical evaluation.2003In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 19, no 7, p. 670-674Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: This study evaluated IPS Empress ceramic inlays luted with two chemical-cured luting agents, a resin-modified glass ionomer cement (Fuji Plus (F)) and a resin composite (RC) (Panavia 21 (P)). METHODS: Seventy-nine ceramic inlays were placed in Class II cavities in 29 patients. At least two inlays were placed in each patient to compare the luting techniques intra-individually. In each patient half of the inlays were luted with F and the other half with P. The inlays were evaluated clinically, according to modified USPHS criteria (van Dijken, 1986), at baseline, after 6 months, and yearly during 5 years. RESULTS: At 5 years, 71 inlays were evaluated. Two small partial fractures were observed at 3 years (1P, 1F). One inlay showed recurrent root caries at 4 years (P). Four inlays, two in each group showed non-acceptable color match (2P, 2F). Small defects were observed in 4 inlays (2P, 2F). A slight ditching of the cement margins was observed in both luting groups but did not seem to increase during the second half of the evaluation. No significant difference in durability was observed between the two luting agents. SIGNIFICANCE: IPS Empress inlays luted with the chemical-cured RC and the resin-modified glass ionomer cement functioned satisfactory during the 5 years follow-up.

  • 16.
    van Dijken, Jan
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Hasselrot, Lars
    A prospective 15-year evaluation of extensive dentin-enamel-bonded pressed ceramic coverages2010In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 26, no 9, p. 929-939Article in journal (Refereed)
    Abstract [en]

    The popularity of tooth-colored posterior restorations has increased during the last years because of a growing demand for esthetics and concern about the biocompatibility of amalgam [1]. Applying the adhesive bonding concept, several dental ceramic systems have been used during the last decades for veneer, inlay and onlay restorations [2]. Most ceramic materials can be bonded to the underlying conditioned tooth surface after etching with hydrofluoric acid or ammonium bifluorid, mediated by use of an enamel/dentin bonding system and a resin composite luting material. Acid etching increase surface roughness and wetting of enamel, dentin and ceramic surfaces, which promote mechanical interlocking of resin bonding systems.

     

    Bulk fracture and loss of restoration have been reported as the main reasons of failure in short-term evaluations of inlays and onlays [3]. Leucite-reinforced glass–ceramic inlays showed improved clinical durability compared to fired ceramics [3], [4] and [5]. The advantage of bonded ceramics can be expected in the extremely non-retentive coverage situation [6], [7], [8] and [9]. Traditional crown preparation techniques will in these cases occasionally result in extensive preparation and/or endodontic treatment in combination with a post and core placement in order to obtain retention. The minimal preparation for the bonded ceramic is less traumatic for the tooth, and pulp vitality can be preserved [9]. There are few preparation design standards for the ideal dentin–enamel-bonded crowns, and Burke [10] showed in vitro no differences between varying degrees of tooth preparation to enhance protection to fracture. The durability of the bonded ceramic will depend on the strength of the bond between tooth, luting system and ceramic and on the inherent strength of the ceramic. The use of chemically cured resin composite cements have been suggested to obtain optimal conversion and decreased stress formation during polymerization [5] and [11].

    Few studies report the longevity of dentin–enamel-bonded all-ceramic crowns also defined as “partial or full coverage restorations in which an all-ceramic is bonded to the underlying dentin and any available enamel using a resin luting material” [1], [9], [12], [13] and [14]. In a systematic review assessing the 5-year survival rates of single crowns, densily sintered aluminum crowns and reinforced glass–ceramic crowns (Empress) showed survival rates comparable to those seen for porcelain-fused-to-metal (PFM) crowns [15]. The short-term results of the extensive adhesively luted coverages are promising but clinical long-term data are not available [9]. The aim of this study was to investigate the long-term durability of these extensive dentin–enamel-bonded posterior ceramic coverages. In addition the effect of luting cement, bonding system and preparation type was studied. The hypothesis tested was that there was (1) no difference in durability for the ceramic coverage placed with different luting agents and different bonding agents, and (2) no difference in durability between vital and endodontic treated teeth.

  • 17.
    van Dijken, Jan
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Pallesen, Ulla
    Long-term dentin retention of etch-and-rinse and self-etch adhesives and a resin-modified glass ionomer cement in non-carious cervical lesions2008In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 24, no 7, p. 905-922Article in journal (Refereed)
    Abstract [sv]

    Objectives: The aim of this study was to evaluate the clinical long-term retention to dentin of seven adhesive systems.

    Methods: A total of 270 Class V restorations of four etch-and-rinse, one self-etch adhesive system and a resin-modified glass ionomer cement were placed in non-carious cervical lesions without intentional enamel involvement. The restorations were evaluated at baseline, 6, 12, 18, and 24 months and then every year during a 13-year follow-up. Dentin bonding efficiency was determined by the percentage of lost restorations.

    Results: During the 13 years, 215 restorations could be evaluated. The cumulative loss rate at 13 years was 53.0%, with significant different failures rates for the different systems varying between 35.6 and 86.8%. Four systems fulfilled the ADA 18-month full acceptance retention criteria. Two systems showed at 18 months and earlier high debonding rates. The annual failure rates for the etch-and-rinse systems were Optibond 3.1%, Permagen 13.0%, Scotchbond MP 4.8%, Syntac classic 2.8%; for the self-etch system P&S 4.4%; and the resin-modified glass ionomer cement Vitremer 2.7%.

    Conclusion: It can be concluded that all systems showed a continuous degradation of the bond with a wide variation, which was independent of the adhesion strategy. Three bonding systems showed a cumulative failure rate after 13 years between 36 and 41% with the best retention for the resin-modified glass ionomer cement and a four-step etch-and-rinse system.

  • 18.
    van Dijken, Jan
    et al.
    Umeå University, Faculty of Medicine, Odontology, Dental Hygiene.
    Sunnegårdh-Grönlund, Karin
    Umeå University, Faculty of Medicine, Odontology, Cariology.
    Lindberg, Anders
    Clinical long-term retention of etch-and-rinse and self-etch adhesive systems in non-carious cervical lesions A 13 years evaluation2007In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 23, no 9, p. 1101-1107Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: The aim of this study was to evaluate the clinical long-term retention to dentin of seven adhesive systems. METHODS: A total of 337 Class V restorations of three three-step etch-and-rinse, one two-step etch-and-rinse and three self-etch adhesive systems were placed in non-carious cervical lesions without intentional enamel involvement. The restorations were evaluated at baseline and then every 6 months during a 13 years follow-up. Dentin bonding efficiency was determined by the percentage of lost restorations. RESULTS: During the 13 years, 275 restorations could be evaluated. The cumulative loss rate at 13 years was 60.3%, with significant different failures rates for the different systems varying between 26.3 and 94.7%. Three materials fulfilled the ADA 18 months full acceptance criteria. Three systems showed already at 18 months or earlier catastrophical debonding rates. The annual failure rates for the three-step etch-and-rinse systems were: Allbond 2 4.1%, Clearfil LB 2.0% and Denthesive 7.3%. For the two-step etch-and-rinse Gluma 2000 6.5%, and for the self-etch systems ART 3.2%, Denthesive 2 5.7% and PUB 3 4.5% CONCLUSION: A continuous degradation of the resin-dentin bond was observed for all bonding systems during the follow-up expressed by the increasing loss rates. A wide variation of dentin bonding effectiveness was seen between the systems independent to adhesion strategy.

  • 19.
    van Dijken, Jan W. V.
    Umeå University, Faculty of Medicine, Department of Odontology, Dental Hygiene.
    A 6-year prospective evaluation of a one-step HEMA-free self-etching adhesive in Class II restorations2013In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 29, no 11, p. 1116-1122Article in journal (Refereed)
    Abstract [en]

    Objective. The aim of this study was to evaluate the clinical effectiveness of a one-step HEMA-free self-etching adhesive (SEA) placed with a micro-fine hybrid resin composite in Class II restorations. The restorations were compared intraindividually with 2-step HEMA containing SEA-giomer restorations. Material and methods. Fifty-four patients with at least one pair of two similar Class II cavities participated (30 men, 24 women; mean age 57.1 yrs). A total of 115 Class II composite restorations were placed with (1) a one step HEMA-free adhesive and a micro-fine hybrid resin composite (Gbond/Gradia Direct: 60; GG) and (2) a 2-step HEMA-containing SEA and a giomer (FL Bond/Beautifil: SS; FB). Each participant received in a randomized way at least one restoration with each of the experimental materials. The restorations were evaluated at baseline and yearly during a 6 year followup using modified USPHS criteria. Results. During the 6 years, 111 restorations could be evaluated. No post-operative sensitivity was reported by the participants. Fourteen failed restorations (12.6%) were observed during the follow up, 5 GG (8.5%; 4 premolar and 1 molar teeth) and 9 FB (17.7%; 1 premolar and 8 molar teeth) (p <0.05). Annual failure rate at 6 years were 1.4% for GB and 3.0% for FB. Main reasons of failure were bulk fracture of resin composite for FB and tooth fracture for GB. Signcance. The HEMA-free SEA-hybrid RC restorations showed good clinical durability in Class II cavities after 6 years. The HEMA-containing SEA-giomer restorations showed a rather high failure frequency. (C) 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  • 20.
    van Dijken, Jan W V
    Umeå University, Faculty of Medicine, Department of Odontology.
    A prospective 8-year evaluation of a mild two-step self-etching adhesive and a heavily filled two-step etch-and-rinse system in non-carious cervical lesions.2010In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 26, no 9, p. 940-946Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: The aim of this study was to evaluate the long-term clinical retention to dentin of a two-step self-etching adhesive system Clearfil SE Bond and a two-step etch-and-rinse system PQ1. METHODS: A total of 119 Class V restorations were placed in non-carious cervical lesions without intentional involvement of the enamel incisal of the lesions. The restorations were evaluated yearly during an 8-year follow-up. Clinical dentin bonding efficiency was determined by the percentage of lost restorations at each of the recalls. RESULTS: At 8 years, 112 restorations could be evaluated. Both adhesives fulfilled the ADA 18-month full acceptance criteria for retention with a retention rate of 90.6% for PQ1 and 98.2% for Clearfil SE Bond. The loss rates increased then considerably after 2 and 3 years, respectively. The cumulative loss rates at 8 years were 25.5% for Clearfil SE and 39.3% for PQ1 (p=0.12). No significant differences were observed between lesions with sclerotic and non-sclerotic dentin. The size of the lesions did not influence the bonding effectiveness. A lower loss rate was found for the restorations placed in lesions slightly roughened before etching. CONCLUSION: Both adhesive systems showed acceptable short-term clinical retention to dentin, which decreased after long-time in vivo aging, especially for the simplified etch-and-rinse system.

  • 21.
    van Dijken, Jan W. V.
    Umeå University, Faculty of Medicine, Department of Odontology.
    A randomized controlled 5-year prospective study of two HEMA-free adhesives, a 1-step self etching and a 3-step etch-and-rinse, in non-carious cervical lesions.2013In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 29, no 11, p. e271-e280Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: The aim of this study was to evaluate the 5 year clinical dentin bonding effectiveness of two HEMA-free adhesives in Class V non-carious cervical lesions.

    MATERIAL AND METHODS: A total of 169 Class V restorations were placed in 67 patients with a self-etching adhesive (G-Bond; 67), a 3-step HEMA and TEGDMA free etch-and-rinse (cfm; 51) and a control HEMA-containing etch-and-rinse adhesive (XP Bond; 51) in non-carious cervical lesions without intentional enamel involvement. The restorations were evaluated at baseline and yearly during a 5 year follow-up with modified USPHS criteria. Dentin bonding efficiency was determined by the percentage of lost restorations.

    RESULTS: During the 5 years, 159 restorations could be evaluated. Good short time dentin retention was observed for the three adhesives, there all adhesives fulfilled at 18 months the full acceptance ADA criteria. At 5 years a cumulative number of 22 lost restorations (13.8%) was observed. The HEMA-free adhesives showed significantly higher dentin retention compared to the HEMA-containing one. Loss of retention was observed for 5 G-Bond (7.9%), 4cfm (8.3%) and 13 XP Bond (27.1%) restorations (p<0.05). No post-operative sensitivity was reported by the participants. No secondary caries was observed.

    SIGNIFICANCE: The durability in non-carious cervical lesions of the HEMA-free adhesives was successful after 5 years. Despite concerns which have been raised, showed the 1-step SEA one of the best reported clinical dentin bonding effectiveness.

  • 22.
    van Dijken, Jan W V
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, School of Dentistry.
    Lindberg, Anders
    A 15-year randomized controlled study of a reduced shrinkage stress resin composite2015In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 31, no 9, p. 1150-1158Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: The aim of this randomized controlled study was to evaluate the long term effectiveness of a reduced shrinkage stress resin composite in Class II restorations. The material was compared intra-individually with a microhybrid resin composite.

    MATERIALS AND METHODS: Each of 50 patients with at least one pair of two similar sized Class II cavities participated (22 female, 28 male, mean age 43 years, range 18-64). Each participant received in each pair, in a randomized way, one Class II restoration performed with a reduced shrinkage stress resin composite (InTen-S) and the other restoration with a microhybrid resin composite restoration (Point 4). Both restorations were placed with an etch-and-rinse bonding system and an oblique layering technique. A total of 106 restorations, 33 premolar and 73 molars, were placed. The restorations were evaluated blindly each year using modified USPHS criteria. The overall performance of the experimental restorations was tested after intra-individual comparison using the Friedmańs two-way analysis of variance test. The hypothesis was rejected at the 5% level.

    RESULTS: At 15 years, 91 restorations were evaluated. The drop out frequency was 15 restorations (5 male, 3 female participants; 2 premolar and 13 molar restorations). Except for 2 participants, who reported slight symptoms during a few weeks after placement, no post-operative sensitivity was observed at the recalls. The overall success rate at 15 years was 77%. Twenty-one non acceptable restorations were observed during the 15 years follow up, 10 InTen-S (21.7%) and 11 Point 4 (24.4%) restorations (p>0.05). Annual failure rates for the resin composites were 1.5% and 1.6%, respectively. The main reasons for failure were secondary caries (8) and resin composite fracture (7). The differences between premolar vs. molar restorations and between restorations in male vs. female participants were not significant. Significant differences were observed between 2-surface vs. 3-surface restorations.

    SIGNIFICANCE: During the 15-year follow up, the reduced shrinkage stress resin composite showed a good clinical durability in Class II cavities, but not significantly better than the control microhybrid resin composite. Secondary caries and material fracture were the main reasons of failure.

  • 23.
    van Dijken, Jan W. V.
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Dental Hygiene.
    Pallesen, Ulla
    Univ Copenhagen, Fac Hlth Sci, Inst Odontol, DK-1168 Copenhagen, Denmark.
    A randomized controlled three year evaluation of "bulk-filled" posterior resin restorations based onstress decreasing resin technology2014In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 30, no 9, p. E245-E251Article in journal (Refereed)
    Abstract [en]

    Objective. The objective of this randomized controlled prospective clinical trial was to evaluate the efficacy of a flowable resin composite (SDR) bulk fill technique in posterior restorations and to compare it intraindividually with a conventional 2 mm resin composite curing technique in a 3-year follow up. Materials and methods. Thirty-eight pairs Class II and 15 pairs Class I restorations were placed in 38 patients with a mean age of 55.3 years (range 32-87). Each patient received at random at least two, as similar as possible, Class II or Class I restorations of two restorative techniques. In all cavities a single step self-etch adhesive (Xeno V) was applied. In one of the cavities of each pair, a flowable resin composite (SDR) was placed, in bulk increments up to 4 mm as needed to fill the cavity 2 mm short of the occlusal cavosurface. The occlusal part was completed with a nano-hybrid resin composite (Ceram X mono) layer. In the second cavity, the hybrid resin composite was placed in 2 mm increments. The restorations were evaluated using slightly modified USPHS criteria at baseline and then yearly during 3 years. Caries risk and parafunctional habits of the participants were estimated. Results. After three years, 76 Class II and 28 Class I restorations could be observed. One molar resin composite-only tooth showed post-operative sensitivity during 3 weeks for temperature changes and occlusal forces. Two failed Class II molar restorations in the resin composite-only group were observed during the first year, one cusp fracture and one resin composite fracture. An annual failure rate of 1.3% was found for the resin composite only restorations and of 0% in the bulk-filled restorations (n.s.). Ten participants were estimated as having high caries risk and eleven showed active bruxing habits. Significance. The 4 mm bulk-fill technique with the flowable resin composite SDR showed highly clinical effectiveness, which was comparable during the 3-year follow-up with the 2 mm resin composite layering technique. 

  • 24.
    van Dijken, Jan W V
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Pallesen, Ulla
    University of Copenhagen.
    A six-year prospective randomized study of a nano-hybrid and a conventional hybrid resin composite in Class II restorations2013In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 29, no 2, p. 191-198Article in journal (Refereed)
    Abstract [en]

    Objective: The objective of this 6 year prospective randomized equivalence trial was to evaluate the long-term clinical performance of a new nano-hybrid resin composite (RC) in Class II restorations in an intraindividual comparison with its well-established conventional hybrid RC predecessor. Methods: Each of 52 participants received at least two, as similar as possible, Class II restorations. The cavities were chosen at random to be restored with an experimental nano-hybrid RC (Exite/Tetric EvoCeram (TEC); n = 61) and a conventional hybrid RC (Exite/Tetric Ceram (TC); n = 61). The restorations were evaluated with slightly modified USPHS criteria at baseline and then annually during 6 years. Results: Two patient drop outs with 4 restorations (2TEC, 2TC) were registered during the follow-up. A prediction of the caries risk showed that 16 of the evaluated 52 patients were considered as high risk patients. Eight TEC (2 P, 6M) and 6 TC (2P, 4M) restorations failed during the 6 years. The main reason of failure was secondary caries (43%; including the failure fracture + secondary caries it increases to 57.1%). 63% of the recurrent caries lesions were found in high caries risk participants. The overall success rate at six years was 88.1%. No statistical significant difference was found in the overall survival rate between the two investigated RC.Significance: The nano-hybrid RC showed good clinical performance during the 6 year evaluation, comparable to the well-established conventional hybrid RC.

  • 25.
    van Dijken, Jan W V
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Pallesen, Ulla
    School of Dentistry, Faculty of Health Science, University of Copenhagen, Denmark.
    Clinical performance of a hybrid resin composite with and without an intermediate layer of flowable resin composite: a 7-year evaluation2011In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 27, no 2, p. 150-156Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: The objective of this prospective clinical follow up was to evaluate the long term clinical performance of a hybrid resin composite in Class II restorations with and without intermediate layer of flowable resin composite.

    METHODS: Each participant received at least two, as similar as possible, Class II restorations of the hybrid resin composite. One resin composite restoration of each pair (59) was chosen at random to be restored with an intermediary layer with flowable resin composite. The other was restored without. The 118 restorations were evaluated using slightly modified USPHS criteria at baseline and then yearly during 7 years.

    RESULTS: Four drop outs were registered during the 7-year follow up (2 with and 2 without flowable) restorations. A prediction of the caries risk showed that 18 of the evaluated 46 patients were considered as high risk patients. Seventeen failures were observed, 8 in restorations with and 9 in restorations without an intermediate layer of flowable resin composite, resulting in a 14.9% failure rate after 7 years. The main reasons for failure were: fracture of resin composite (8), secondary caries (4) and cusp fracture (3). No statistical difference was seen between restorations restored with and without flowable layer.

    CONCLUSION: The hybrid resin composite showed a good clinical performance during the 7-year evaluation. The use of flowable resin composite as an intermediate layer did not result in improved effectiveness of the Class II restorations.

  • 26.
    van Dijken, Jan W V
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Pallesen, Ulla
    Durability of a low shrinkage TEGDMA/HEMA-free resin composite system in Class II restorations: A 6-year follow up2017In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 33, no 8, p. 944-953Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: The objective of this randomized controlled prospective trial was to evaluate the durability of a low shrinkage and TEGDMA/HEMA-free resin composite system in posterior restorations in a 6-year follow up.

    METHODS: 139 Class II restorations were placed in 67 patients with a mean age of 53 years (range 29-82). Each participant received at random two, as similar as possible, Class II restorations. In the first cavity of each pair the TEGDMA/HEMA-free resin composite system was placed with its 3-step etch-and-rinse adhesive (cmf-els). In the second cavity a 1-step HEMA-free self-etch adhesive was used (AdheSe One F). The restorations were evaluated using slightly modified USPHS criteria at baseline and then yearly during 6 years. Caries risk and parafunctional habits of the participants were estimated.

    RESULTS: Three molar teeth showed mild post-operative sensitivity during 3 weeks for temperature changes and occlusal forces. After 6 years, 134 Class II restorations were evaluated. Twenty-one restorations, 8 cmf-els (11.4%) and 13 ASE-els (20%) failed during the 6 years (p<0.0001). The annual failure rates were 1.9% and 3.3%, respectively. The main reasons for failure were fracture followed by recurrent caries. Most fractures and all caries lesions were found in high risk participants.

    SIGNIFICANCE: The Class II resin composite restorations performed with the new TEGDMA/HEMA-free low shrinkage resin composite system showed good durability over six years.

  • 27.
    van Dijken, Jan W. V.
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Pallesen, Ulla
    Benetti, Ana
    A randomized controlled evaluation of posterior resin restorations of an altered resin modified glass-ionomer cement with claimed bioactivity2019In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 35, no 2, p. 335-343Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: The objective of this randomized controlled prospective clinical trial was to evaluate the short time clinical behaviour of an altered resin modified glass-ionomer cement (RMGIC), which is claimed to possess bioactivity, in posterior restorations and to compare it intraindividually with a nanofilled resin composite.

    METHODS: Totally 78 pairs Class II and 4 pairs Class I restorations were placed in 29 female and 38 male participants with a mean age of 58.3 years (range 37-86). Each patient received at random at least one pair of, as similar as possible, Class II or Class I restorations. In the first cavity of each pair, the modified flowable RMGIC (ACTIVA Bioactive; AB) was placed after phosphoric acid etching of the cavity and without adhesive, according to the instructions of the manufacturer. In the other cavity a well established nanofilled resin composite (CeramX; RC) with a single step self-etch adhesive (Xeno Select) was placed. The restorations were evaluated using slightly modified USPHS criteria at baseline, 6 and 12 months. Caries risk and parafunctional habits of the participants were estimated.

    RESULTS: 158 restorations, 8 Class I and 150 Class II, were evaluated at the one year recalls. At baseline two failed restorations were observed (2AB), at 6 months six failures (5AB, 1RC) and at 12 months another thirteen failed restorations were observed (12AB, 1RC). This resulted in annual failure rates of 24.1% for the AB and 2.5% for RC (p<0.0001). The main reasons for failure for AB were lost restorations (5), postoperative symptoms (4) and secondary caries (3). Do to the unacceptable very high one-year failure frequency, the clinical study was stopped and no further evaluation will be performed.

    SIGNIFICANCE: The use of the AB restorative in Class II cavities, applied as instructed by the manufacturer after a short phosphoric acid pretreatment but without adhesive system, resulted in a non-acceptable very high failure frequency after a one year period. Further studies should be conducted using a bonding agent.

  • 28. van Heumen, Céleste C M
    et al.
    Tanner, Johanna
    van Dijken, Jan W V
    Umeå University, Faculty of Medicine, Department of Odontology.
    Pikaar, Ronald
    Lassila, Lippo V J
    Creugers, Nico H J
    Vallittu, Pekka K
    Kreulen, Cees M
    Five-year survival of 3-unit fiber-reinforced composite fixed partial dentures in the posterior area.2010In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 26, no 10, p. 954-960Article in journal (Refereed)
    Abstract [en]

    Objectives: The purpose of this clinical study was to evaluate the long-term outcome of three-unit posterior fixed partial dentures (FPDs) made of fiber-reinforced resin composite (FRC), and to identify design factors influencing the survival rate.

    Methods: 77 patients (52 females, 25 males) received 96 indirectly made FRC FPDs, using pre-impregnated unidirectional glass-fibers, requiring manual wetting, as framework material. FPDs were surface (n = 31) inlay (n = 45) or hybrid (n = 20) retained and mainly located in the upper jaw. Hybrid FPDs consisted of a wing retainer at canine and an inlay retainer at distal abutment tooth. Surface FPDs consisted of uplay and wing combinations. Follow-up period was at minimum 4.5 years, with checkups at every 1–2 years. The study was carried out by six operators in three centers in the Netherlands, Finland and Sweden. Survival rates, including reparable defects of FPDs, and success rates were determined.

    Results: Kaplan–Meier survival rate at 5 years was 71.2% (SE 4.8%) for success and 77.5% (SE 4.4%) for survival. Differences were not significantly different. Main failure modes were delamination and fracture of the FPD. Only FPDs with surface retainers showed debonding.

    Conclusions: A success rate of 71% and a survival rate of 78% after 5 years was found. Survival rates of inlay, hybrid and surface retained FPDs did not significantly differ.

  • 29. van Heumen, Céleste C M
    et al.
    van Dijken, Jan W V
    Umeå University, Faculty of Medicine, Department of Odontology.
    Tanner, Johanna
    Pikaar, Ronald
    Lassila, Lippo V J
    Creugers, Nico H J
    Vallittu, Pekka K
    Kreulen, Cees M
    Five-year survival of 3-unit fiber-reinforced composite fixed partial dentures in the anterior area2009In: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 25, no 6, p. 820-827Article in journal (Refereed)
    Abstract [en]

    Objectives: The purpose of this clinical study was to evaluate the long-term outcome of 3-unit anterior fixed partial dentures (FPDs) made of fiber-reinforced resin composite (FRC), and to identify design factors influencing the survival rate.

    Methods: 52 patients (26 females, 26 males) received 60 indirectly made FRC FPDs, using pre-impregnated unidirectional glass fibers, requiring manual wetting, as framework material. FPDs were surface (n = 48) or hybrid (n = 12) retained and mainly located in the upper jaw. Hybrid FPDs had a combination of retainers; i.e. crown at one and surface retention at the other abutment tooth. Surface FPDs were either purely adhesively retained (n = 29) or with additional mechanical retention (n = 19). Follow-up period was at minimum 5 years, with check-ups every 1–2 years. Six operators were involved, in three centers in the Netherlands, Finland and Sweden. Survival rates, including repairable defects of FPDs, and success rates were determined.

    Results: Kaplan–Meier survival rate at 5 years was 64% (SE 7%). For the level of success, values were 45% (SE 7%) and the estimated median survival time 58 (SE 10.1) months. For surface FPDs, additional mechanical retention did not improve survival significantly. There was a trend towards better survival of surface FPDs over hybrid FPDs, but differences were not significant. Main failure modes were fracture of the FPD and delamination of veneering composite.

    Significance: A success rate of 45% and a survival rate of 64% after 5 years was found. Fracture of the framework and delamination are the most prevalent failure modes, especially for surface FPDs.

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