PubMed · 2981013
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J D Debising. 1987. An acid-etch fixed prosthesis.. https://pubmed.ncbi.nlm.nih.gov/2981013/
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OBJECTIVES: To examine the effect of porcelain surface texture achieved utilising three clinically relevant surface preparation methods prior to silane and unfilled resin application on the flexure strength of a low fusing feldspathic porcelain. MATERIALS AND METHODS: Five hundred and forty dentine disc-shaped specimens (15.0mm diameter and 0.9mm thickness) were condensed, fired and allocated to 18 groups. Six groups were stored as-fired, six were alumina abraded and six were acid-etched. Samples were coated with silane, unfilled resin or both prior to bi-axial flexure testing. Group means were compared utilising a three factor design general linear model and post hoc all paired Tukey tests at P<0.05. Weibull analysis was employed to examine the reliability of the strength data. Profilometry was used to characterise the surface texture of the specimen surfaces. RESULTS: Alumina abraded and acid-etched specimens had significantly lower flexure strengths than the as-fired specimens. A significant difference between the degree of strengthening observed following unfilled resin application on the three surface texture investigated was observed (P<0.001). Silane application prior to resin coating resulted in no further significant increases in the mean bi-axial flexure strengths of the three surface textures. The as-fired surfaces had a low frequency of irregular amplitude defects, alumina abraded surfaces had an increased frequency of regular amplitude defects whilst the acid-etched surface consisted of an increased frequency of irregular amplitude defects. CONCLUSION: The strengthening mechanism whilst dependent on surface texture was independent of defect severity. No significant strengthening occurred following silane priming suggesting that, for the unfilled resin utilised, the strengthening mechanism was not enhanced by improved resin-ceramic adhesion.
AIM: A unique characteristic of some new bonding systems in operative dentistry is they combine conditioning and priming agents into a single acidic primer solution for simultaneous use on both enamel and dentin. Combining conditioning and priming into a single treatment step results in improvement in both time and cost-effectiveness to the clinician and, indirectly, to the patient. The purpose of this study was to determine the effects of the use of a self-etching primer on the bond strength of orthodontic brackets and on the bracket/adhesive failure mode. METHODS AND MATERIALS: Thirty-six fresh bovine incisors were collected and stored in a solution of 0.1% (weight/volume) thymol. The criteria for tooth selection included intact buccal enamel, no cracks caused by the presence of the extraction forceps, and no defects. The teeth were cleansed and polished with pumice and rubber prophylactic cups for ten seconds. Brackets were bonded to the teeth according to one of three protocols following the manufacturers' instructions--Group 1: Conventional multistep bonding system (control group) (n=12); Group 2: Self-etching primer system (n=12); and Group 3: Acid+self-etching primer system (n=12). Specimens were loaded to failure in a Zwick test machine (Zwick GmbH & Co, Ulm, Germany). Shear bond strengths were measured at a crosshead speed of 5 mm/min. RESULTS: The mean shear bond strength in megapascals (Mpa) (standard deviation) were 11.7 (4.2), 10.5 (4.4), and 10.9 (4.8) for Groups 1, 2, and 3, respectively. The analysis of variance (ANOVA) was used to compare the three groups. The results indicated no significant difference in the bond strength between the three groups (P=0.800). The results of the Chi square test, evaluating the residual adhesives on the enamel surfaces, revealed no significant difference between the three groups (P=0.554). CONCLUSION: Results of the present in vitro study indicate the use of self-etching primers may be an alternative to conventional phosphoric acid pre-treatment in orthodontic bonding.
The structural integrity of fibrillar type I collagen is critical for effective dentin bonding. Since most noncollagenous matrix components in dentin are closely associated with collagen, we hypothesized that they may also contribute to dentin bonding. To test this hypothesis, bovine dentin was acid-etched, treated with chondroitinase ABC (C-ABC), endo-beta-galactosidase (Endo-beta), or trypsin. Controls were prepared in the same manner but without the enzymes. All control and experimental specimens were then bonded with One-Step. Bond strength data were analyzed by one-way ANOVA and Fisher's PLSD test (p < 0.05). When dentin was treated with C-ABC or trypsin, bond strengths significantly decreased for the rewetted groups (p < 0.05). The treatment with Endo-beta showed no effects on bond strengths (p > 0.05). When the treated dentin surfaces were observed under SEM, the C-ABC and trypsin treated groups revealed significant loss of collagen fibril architecture. The results indicate that chondroitin sulfate glycosaminoglycans and trypsin-digestible noncollagenous proteins play roles in maintaining the open dimensions of the collagen fibril scaffold, which is essential for optimal dentin bonding.