Bond strength and failure analysis of light-cured denture resins bonded to denture teeth.

Department of Prosthodontics, University of Iowa, College of Dentistry, Iowa City.
Journal of Prosthetic Dentistry (Impact Factor: 1.42). 03/1991; 65(2):315-24. DOI: 10.1016/0022-3913(91)90182-V
Source: PubMed

ABSTRACT This study examined the tensile bond strength and failure sites of one heat-cured (Microlon) and two visible light-cured (Triad and Extoral) denture resins to two types of denture teeth. The resins were processed into cylinders against denture teeth milled to the same size. Half of the specimens were thermocycled. After tensile testing, statistical analysis (p 0.05) showed that the strongest bond was achieved with the heat-cured resin Microlon, whereas Triad resin displayed the stronger bond between the two light-cured resins. Scanning electron microscopic analysis showed that the nature and location of the fracture sites was different among the three resins tested.

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    ABSTRACT: Background: Debonding of acrylic teeth from the denture base is a common problem. Certain clinical conditions like ridge prominence leads to excess trimming of acrylic teeth and base, resulting in a weak interface. The denture base polymer debonds adhesively in the region of the highly cross -linked matrix of the teeth. To compare the effect of different chemical surface treatments on the bond between cross-linked acrylic teeth and different types of denture base material. Materials & Methods: A total of 180 wax specimens were fabricated and divided into 3 groups: Heat-cure, high impact heat-cure, flexible denture base material bonded to acrylic teeth. Each group was further subdivided into 6 subgroups with 10 specimens each according to the surface treatment ofthe ridge lap area: control, monomer, acetone 99%, chloroform 99%, acrylic adhesive cyanoacrylate, ethyl acetate 99%. After processing, specimens were tested for bond strength using a universal testing machine. The resulting bond strengths were recorded, statistically analyzed and compared. Results: Among all the 3types of denture base resins, highimpact heat-cure denture base resin gave highest bond strength. There was no bonding of teeth with flexible denture base material. Chemical surface treatment of acrylic teeth with ethyl acetate gave highest bond strength followed by control, chloroform, acetone and cyanoacrylate groups. Conclusion: Among all the 3types of denture base materials, high-impact heat-cure denture base resin gave highest bond strength with ethyl acetate surface treatment. Simple and quick tooth chemical surface treatment with ethylacetate could be an effective option in decreasing bonding failures and also avoid repeated denture repairs improving patient satisfaction. How to cite the article: Krishna VP, Premalatha A, Babu PJ, Raju DS, Kumar MP, Rao DB. Effect of various chemicals on the bond strength of acrylic tooth and denture base -An In-vitro comparative study. J Int Oral Health 2014;6(1):100-5.
    Journal of international oral health : JIOH. 02/2014; 6(1):100-5.
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    ABSTRACT: PurposeThis study analyzed the conventional method of rebonding a denture tooth, evaluating the effect of varied thickness of autopolymerizing acrylic resin on the bond strength and the failure mode.Materials and MethodsA total of 52 heat-polymerizing acrylic resin specimens were fabricated with an anterior denture tooth. A cantilever-type bending force was applied with a universal testing machine to each specimen until failure. The failure mode was determined, and cohesive failures were excluded from part II. Thirty specimens were randomly selected and divided into three groups (n = 10). For each group, resin was relieved from the bonding area to create a 0, 1, or 3 mm space. The tooth was repositioned using its matrix and reattached to its base, filling the relieved space with autopolymerizing acrylic resin. The repaired specimens were tested using the same parameters. Data were analyzed with paired t-tests, one-way ANOVA, and post hoc test. Statistical significance was determined at p < 0.05.ResultsThe mean peak load to failure for the part I group was 88.91 N. While the peak load to failure decreased to 71.96 N (19.69% loss of original bond strength), statistical analysis revealed no difference between the bond strength of the specimens repaired with a 0 mm thickness of autopolymerizing acrylic resin and the original (part I) group (p > 0.05). The bond strength was lower for the group repaired with a 1 mm thickness compared to the original (part I) group (p < 0.05), with 65.8 N load to failure (29.63% loss). The bond strength was even lower for the group repaired with a 3 mm thickness (p < 0.05), with 58.64 N load to failure (33.07% loss). Post hoc analysis revealed a significant difference between the 0 and 3 mm groups (p = 0.04). The most common failure mode in the original group was adhesive (56%), then combination (34%), then cohesive (9.8%). The repaired group (n = 30) had similar results, with 56.7% adhesive, 36.7% combination, and 6.7% cohesive failures.Conclusions The bond strength of a replaced denture tooth is affected by the thickness of the autopolymerizing acrylic resin. The failure mode of a rebonded denture tooth follows the same trend of the original failure. If possible, replace teeth with no relief. If combination failure occurs, leave residual base acrylic resin on the ridge lap.
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    ABSTRACT: Abstract Objective: The purpose of this study was to investigate the effects of various surface pretreatments in the ridge lap area of acrylic resin denture teeth on the shear bond strength to heat-polymerized polymethylmethacrylate (PMMA) denture base resin. Background data: Tooth debonding of the denture is a major problem for patients with removable prostheses. Methods: A total of 84 central incisor denture teeth were used in this study. Seven test groups with 12 specimens for each group were prepared as follows: untreated (control, group C), ground, with a tungsten carbide bur (group H), airborne-particle abrasion (group AA), primed with methyl methacrylate (group M), treated with izobutyl methacrylate (group iBMA), Eclipse Bonding Agent applied (group E), and Er:YAG laser irradiated (group L). Test specimens were produced according to the manufacturers' instructions and mounted to a universal testing machine for shear testing with a crosshead speed of 1 mm/min. Data were evaluated by one way variance analysis (ANOVA) and Tukey's test (α=0.05). Results: Similar bond strength values were found between groups L and M, and these were the highest shear bond strengths among the groups. The lowest one was observed in group E. All surface treatments, except group E, exhibited significant difference when compared with group C (p<0.05). Conclusions: Lasing of the ridge lap area to enhance the bond strength of acrylic resin denture teeth to PMMA denture base resin might be an alternative to wetting with MMA monomer. To overcome tooth debonding, surface treatment of the ridge lap area should be performed as part of denture fabrication.
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