Marginal adaptation of self-etching adhesives in Class II cavities.

PURPOSE: An in vitro dye-penetration study was performed on 2 different self-etching adhesives (Prompt L-Pop II, 3M-Espe; NRC, Prime&Bond NT Quix, Dentsply/DeTrey) in comparison to conventional conditioning of the cavity with phosphoric acid (Conditioner 36, P&B NT Quix, Dentsply/DeTrey). MATERIALS AND METHODS: Standardized mod cavities (one cervical margin in cementum, one in enamel) were prepared in 80 extracted human teeth (n = 20/group). Prompt L-Pop II was employed in two different sequences: A: placing the matrix band first, then applying the adhesive, B: first applying the adhesive, then placing the matrix band. The adhesive was cured in both cases. Conditioning and application of P&B NT Quix was carried out after placement of the matrix band in both procedures. The compomer Dyract AP was used as a restorative material in all cavities. After thermocycling, the median percentages of dye-penetrated (2% methylene blue) margins were determined separately for the cementum and enamel margins of the approximal boxes and for the lateral enamel margins of the boxes. RESULTS: The results showed that when using Prompt L-Pop II in Class II cavities, the adhesive should be applied before placing the matrix band (p < 0.0001). When the matrix band was placed first, P&B NT Quix showed superior results at a statistically significant level (p < 0.0001) in comparison to Prompt L-Pop II. There was no significant difference in the use of P&B NT Quix in combination with NRC or phosphoric acid in these Class II cavities. CONCLUSION: It is strongly recommended that Prompt L-Pop be applied prior to placement of the matrix band. Prime & Bond NT Quix seems to provide clinically relevant marginal seal in Class II cavities, regardless of whether NRC or phosphoric acid is used for conditioning.