Gap Formation on Occlusal Surfaces Using a Novel Resin Composite

Objectives: To evaluate occlusal marginal adaptation of a new resin compared to three commercially available resin brands on Class I restorations.

Methods:         Twenty freshly extracted human molars were randomly divided into four groups (n=5). A standardized Class I preparation 4mm x 4mm x 6mm was made on each tooth with the cavosurface margins defined by a distance of 1 mm from the cusp tips. Restorations were placed according to manufacturer's instructions using the new resin P&P flowable (Dentsply-Caulk, USA) and the commercial resins Z100 (3M ESPE, USA), Filtek Supreme Plus (3M ESPE, USA), and Surefil (Dentsply-Caulk, USA). Epoxy replicas of the occlusal surfaces were prepared and examined under a scanning electron microscope (200X). Marginal gaps and sealed margins were assessed in terms of percentage of total margin length. The total gap area and the number of gaps in each specimen were also determined. One-way analysis of variance (ANOVA) was used to assess whether significant differences existed among study groups at 95% significance.

Results:           No significant differences were detected for the mean gap areas (P=0.20) or for the number of gaps (P=0.07). However, significant differences were observed for the percentage of sealed margins (P=0.02). Surefil showed the highest percentage of sealed margin (76%, SD 14%). Values for this resin did not differ (P=0.278) from P&P (62%, SD 31%) but showed statistically significant differences (P=0.036 and P=0.021) respect to Filtek (38%, SD 14%) and Z100 (38%, SD 14%).

Conclusions: There are material-dependent differences in the occlusal sealing ability among the studied materials. Surefil and P&P showed the highest percentages of sealed margins, while Filtek and Z100 showed lower percentage of sealed margin than Surefil.  This study was partially funded by Dentsply/Caulk.