ANÁLISE IN VITRO E IN VIVO DE DIFERENTES FORMAS DE APLICAÇÃO DE SISTEMAS ADESIVOS AUTOCONDICIONANTES

Abstract

The objective of this study was to evaluate the effect of different modes of application (active vs. inactive) of one step self-etch adhesives under in vitro conditions (resindentin bond strength [BS] and nanoleakage under Scaning Electron Microscopy [SEM]) and in vivo conditions (in non carious class V restorations) in the immediate [IM] and 6 month period [6M]. For the in vitro test, 32 human third molars (20 for BS and 12 for SEM) had their occlusal dentin exposed by wet abrasion with 600-grit SiC paper. The following adhesives Adper Prompt [AP] and Xeno II [XE] were applied under inactive [I] or following vigorous application mode [V] in two coats, which were then ligh-cured for the recommended time. Composite “crowns” were incrementally constructed and the after storage (37C/24 h) the specimens were sectioned in both “x” and “y” direction to obtain bonded sticks (0.8 mm2) to be tested in tension (0.5 mm/min). Half of the specimens were tested I or after 6M of water storage. A threeway ANOVA and Tukey test was used to statistically evaluate the data (0,05). For the clinical study, 120 restorations were placed in non carious cervical lesions in 30 patients, in a way that all four experimental conditions were placed in the same patient. The restorations were evaluated according the modified USPHS. The differences for each adhesive at baseline and 6 months were analysed Fisher’s (0,05) and the performance of each mode of application for each adhesive at each period of evaluation was evaluated by Mc Nemar’s test ( 0,05). In the immediate time, an increase in the BS and lower nanoleakage was observed when both adhesive were applied under A mode. However, after 6 months, the BS were reduced ad a higher nanoleakage occurred for both adhesives regardless the mode of application. Under the in vitro part of the study, 29 patients attended the 6 month recall. Only one AP restoration debonded after 6 months in the inactive mode. Based on the results of the present investigation one can conclude that: 1) although the vigorous application improves the immediate performance of the adhesive systems tested, no improvement was observed after 6 months of water storage. 2) After the short-term evaluation of 6 months no significant difference was observed in none of the USPHS items for the experimental conditions.