RESUMO
This study evaluated bond strength of glass fiber posts to root dentin using push-out (PO) and diametral compression (DC), testing glycolic acid as a conditioner and varying dentin moisture. An additional aim was to test whether DC can be an alternative test to PO for bond strength assessment. Eighty bovine teeth were divided into eight groups (n = 10) defined by the use of either 37% glycolic acid or 37% phosphoric acid (PA) on moist or wet dentin before bonding with either Adapter SingleBond/RelyX ARC or One Step Plus/Duo-Link Bisco. Each tooth provided discs with an internal diameter of 2 mm, external diameter of 5 mm, and height of 2 mm, which underwent PO and DC. Finite element analysis (FEA) was carried out on 3D models. When analyzing PO results through linear regression, the highest values of bond strength were observed using glycolic acid on wet dentin in the cervical and middle thirds of the teeth. Analyzing DC results, the only statistical influence on values was the dental thirds. The scatterplot of the DC results and the PO bond strength values indicated no relationship between the results of the two tests (r = 0.03; p = 0.64). PO test detected more sensitive changes in bond strength values than DC.
Assuntos
Colagem Dentária , Dentina , Análise de Elementos Finitos , Vidro , Ácidos Fosfóricos , Técnica para Retentor Intrarradicular , Animais , Bovinos , Dentina/efeitos dos fármacos , Vidro/química , Ácidos Fosfóricos/química , Adesivos Dentinários/química , Cimentos de Resina/química , Análise do Estresse Dentário , Teste de Materiais , Raiz Dentária , Glicolatos/química , Condicionamento Ácido do DenteRESUMO
Aim: The aim of this study was to evaluate, in vitro, the influence of four different dentin drying methods (air drying for 10s, absorbent paper, endodontic suction cannula and air drying for 10s with subsequent re-wetting with distilled water), after etching with phosphoric acid gel 37%, on bond strength and microleakage of composite restorations. Material and Methods: Twenty sound bovine incisors were selected and sectioned transversely. The buccal surfaces were frayed until exposure of dentin, etched and washed with distilled water. Each specimen was subjected to one of the four different drying methods. A 3-step total-etch adhesive system (Adper Scotchbond™ Multi-Purpose) was used on 10 teeth and on the other 10, a 2-step total-etch adhesive system (Adper Single BondT™ 2) was used. Composite resin restorations in cylindrical shapes were made and, after thermocycling, the teeth were subjected to the microshear bond strength test. Cervical areas of the teeth were prepared and restored with the same techniques describe above. Cervical restorations were cut and subjected to microleakage analysis in the cervical margin. Data obtained were tabulated and statistically analyzed, using ANOVA, Chi-square and Kruskal-Wallis tests, and the significance level was set at 5%. Results: The results showed no statistically significant differences among the groups tested. Conclusions: It was concluded that all drying methods tested represent feasible alternatives to clinical application for total etch dentin-bonding agents.