Nanohybrid vs. fine hybrid composite in extended class II cavities: 8-year results

In a controlled prospective split-mouth study, clinical behavior of two different resin composites in extended class II cavities was observed over 8 years.

Thirty patients received 68 direct resin composite restorations (Solobond M/Grandio, Voco--n = 36; Syntac/Tetric Ceram, Ivoclar Vivadent--n = 32) by one dentist in a private practice. Thirty-five percent of cavities revealed no enamel at the bottom of the proximal box, 48% of cavities provided <0.5 mm remaining proximal enamel width. Restorations were examined according to modified US Public Health Service criteria at baseline, after 6 months, and 1, 2, 4, 6, and 8 years.

All patients attended the 8-year recall. The overall success rate of all restorations was 98.5% (Kaplan-Meier survival algorithm). One Grandio restoration was lost due to bulk fracture. One Tetric Ceram restoration suffered drop out due to cusp fracture having been not related to the restoration itself. Neither restorative materials nor localization of the restorations had a significant influence on any criterion except color (darker for Grandio). Restorations in molars performed inferior compared with premolars regarding marginal integrity (4 years), restoration integrity (6, 12, 24, 48, and 96 months), and tooth integrity (12, 48, 72, and 96 months). Irrespective of the resin composite used, significant changes over time were found for all criteria evaluated in clinical examinations. Beyond the 4-year recall, marginal staining increased. Both phenomena were found earlier in molars compared with premolars. Tooth integrity significantly deteriorated because of increasing enamel cracks and chippings over time.

Both materials performed satisfactorily over the 8-year observation period. Due to the extension of the restorations, wear was clearly visible after 8 years of clinical service.

Hybrid and nanohybrid resin composites show an acceptable clinical performance after 8 years of service.