Self-etching adhesives and postoperative sensitivity.
PURPOSE: To test the hypothesis that the prevention of postoperative sensitivity in resin-based composite restorations is better achieved with a self-etching/self-priming (SE/SP) dentin bonding system without lining than with an early generation total-etch (TE) bonding system. METHODS: Over a 4-year period, clinical follow-ups were conducted on patients who had received composite restorations. The depth of each cavity was categorized as being shallow, medium or deep, and an evaluation was made regarding the need for pulpal protection for each restoration. Three different self-etching/self-priming (SE/SP) adhesive systems were compared to three different total-etch (TE) adhesive systems. The incidences of postoperative sensitivity (IPS) were examined by a standardized procedure 1 week after placement of the restoration. Patients' ages varied between 16-83 years. RESULTS: The total number of restorations placed in vital teeth were 330 for 150 patients in the SE/SP group, and 126 for 70 patients in the TE group. Incidences of IPS in the total number of restorations stratified for depth were 14% in deep cavities, 6% in medium depth cavities and 5% in shallow cavities in the SE/SP group, and 35% in deep cavities, 16% in medium and 4% in shallow cavities in the TE group. Fisher's exact test showed the incidence of IPS was significantly higher in cases of deep (P< 0.05) and medium (P< 0.05) cavities. The test also revealed that in restorations placed with the SE/SP adhesive systems, the presence or absence of a protective liner or base made no significant difference in the IPS in medium and shallow cavities, while the use of such protective layers produced a significantly higher IPS (21%), compared with no protection (0%), in deep cavities (P< 0.05). The absence of protective liners or bases did not result in postoperative sensitivity in deep cavities, when the SE/SP dentin bonding systems were used.