Light-polymerization of composite resins through different thicknesses of dental tissue

Resumen

Objective: To determine the thickness of dental tissue through which Prime Dent Resin® might exhibit light-polymerization with minimum shrinkage and suitable curing depth. Method: 80 laminae measuring 1, 2, 3 and 4 mm thickness were obtained from molars (20 laminae per group). Contraction was measured and resin shrinkage was calculated by polymerization (Visilux 2, 3M) though each lamina (60 s, 400 mW/cm2). Bonded-disk technique was used. Depth of curing tests were undertaken by measuring the thickness of polymerized resin according to ADA’s specifi cation number 27. A control group without dental tissue was prepared for both properties. Data were analyzed using ANOVA with Tukey test (p < 0.001). Results: Curing depth: curing depth decreased as thickness increased. All groups revealed statistically significant differences. The thickness that exhibited lesser shrinkage nonetheless meeting with suitable curing depth (ADA establishes minimum value of 1 mm) was the 3 mm
group. Shrinkage: as thickness increased, shrinkage decreased; no statistically signifi cant difference was reported for groups 2 and 3 mm. Conclusions: According to obtained results, it is possible to polymerize through a 3 mm thickness, therefore polymerization is not recommended through a 4 mm depth. It will be necessary to obtain further mechanical properties using different thicknesses of dental tissue.