Nanohybrid composite vs. fine hybrid composite in extended class II cavities: clinical and microscopic results after...

To evaluate the clinical behavior of two different resin composites in Class II cavities over a period of 2 years in a controlled prospective split-mouth study.

30 subjects received 68 direct resin composite restorations (Grandio bonded with Solobond M: n=36, Tetric Ceram bonded with Syntac: n=32) by one dentist in a private practice. All restorations were replacement restorations, 24 cavities (35%) revealed no enamel at the bottom of the proximal box, in 33 cavities (48%) the proximal enamel width was < 0.5 mm. The restorations were examined according to modified USPHS criteria at baseline, and after 0.5, 1, and 2 years. At each recall, impressions were taken to prepare replicas. Replicas of 44 selected subjects were assessed for marginal quality under a stereo light microscope (SLM) at x130, and 22 replicas were assessed under a SEM at x200.

Both recall rate and survival rate were 100% after 2 years of clinical service. No significant difference was found between the restorative materials (P > 0.05; Mann-Whitney U-test). A significant deterioration was found over time for marginal integrity, tooth integrity, restoration integrity and proximal contact (P < 0.05; Friedman test). SLM and SEM analysis of restoration margins only revealed differences in the amount of detectable perfect margins, in favor of Tetric Ceram (P < 0.05). Both materials performed satisfactorily over the 2-year observation period.