Internal Marginal Gap Formation using a Novel Resin Composite Restorative

A recently developed restorative resin is hypothesized to improve marginal adaptation due to its increased flowability.

Objectives: This study evaluated the internal marginal adaptation of a new resin P&P Flowable (P&P) (Dentsply Caulk, USA), compared to three commercially available resins: Z100 (Z); Filtek Supreme Plus (F) (3M ESPE, USA) and Surefil (S) (Dentsply Caulk, USA) on Class I restorations.

Methods: Class I preparations were made on twenty extracted human molars with the following dimensions: 4mm x 4mm x 6mm, and with the cavosurface margins defined by a distance of 1 mm from the cusp tips. The teeth were randomly divided into four groups (n=5) and restored with the four resins previously described. Each of the tested restorative materials was bonded and restored according to manufacturer's instructions. The specimens were sectioned mesio-distally and replicas of the internal surfaces were obtained using a light viscosity PVS and epoxy resin. The replicas were examined under scanning electron microscope at 200X. Sealed/open margins were assessed in terms of percentage of total margin length. The number of gaps and surface area of the existing gaps were also evaluated. ANOVA was used to evaluate whether significant differences in gap formation existed among groups.

Results: There were significant differences among the tested restorative materials in both percentage of sealed margins (p<0.001) and total gap area (p=0.004). P&P exhibited the highest percentage of sealed margins and the smallest total gap area. No significant differences were found in the number of gaps (p=0.08) among groups. Most gaps occurred on the occlusal third of the axial walls except for Surefil which displayed the most gaps along the pulpal wall.

Conclusions: Overall, P&P Flowable exhibited the best marginal adaptation and Surefil the worst. Study partially funded by Dentsply.