Resumo

BARBOSA, Alcebiades Nunes  e  PIAZZA, José Luiz. Fracture resistance of teeth with structural loss restored with composite resin and self-etching adhesive system. RSBO (Online) [online]. 2010, vol.7, n.1, pp. 11-18. ISSN 1984-5685.

INTRODUCTION: One of the current concerns in dentistry is the search for new restorative techniques and materials, aiming the recovering of lost portions of the dental element with restorations that ensure the greatest longevity. OBJECTIVE: To evaluate fracture resistance of maxillary premolars that show deep cavity preparations and are restored with composite resin (3M ESPE Z250) associated with a conventional one-bottle adhesive (3M ESPE Adper Single Bond) or a two-step self-etching adhesive (Clearfil SE Bond, Kuraray). MATERIAL AND METHODS: Thirty-two healthy maxillary premolars were selected, embedded from the root in chemically activated acrylic resin inside PVC plastic cylinders and randomly divided into 4 groups: G1 - healthy teeth without preparation (positive control); G2 - only preparation (negative control); G3 - restoration with conventional one-bottle adhesive (two-step); G4 - restoration with self-etching adhesive. All samples were submitted to fracture toughness test using a universal testing machine Versat 502 at a speed of 0.5 mm/min. RESULTS: Mean resistance values, expressed as kgf, for the different groups were as follows: G1 - 147.60 (±24.74); G2 - 56.51 (±11.64); G3 - 135.31 (±42.92); G4 - 81.13 (±18.05). The data obtained were submitted to statistical analysis (ANOVA), complemented with the Tukey test for multiple comparisons, and the level of significance was set at 1%. CONCLUSION: Group 1 (healthy teeth) showed the highest fracture resistance mean, similar to group 3 (teeth restored with conventional adhesive); groups 2 (teeth with preparation) and 4 (teeth restored with self-etching adhesive) showed statistically similar mean resistance values, although lower than the mean values found in groups 1 and 3; the self-etching adhesive system presented a significantly lower result when compared to the conventional one-bottle adhesive system.

Palavras-chave : dentin-bonding agents; tooth fractures; premolars.