Internal and marginal adaptation of the occlusal replica technique with different materials, restored with bulk fill resin: in vitro study

Abstract

Extensive composite restorations in posterior teeth present several challenges. One of the main ones is to achieve adequate occlusal contacts and accurately reproduce the natural anatomical shape of the cusps and pits. To address this problem, techniques, such as the use of occlusal replicas, have been developed to more closely copy the occlusal morphology. This method requires less invasive preparation, but marginal and internal adaptation is important for longevity. Objective: To evaluate the internal and marginal adaptation using different materials associated with the occlusal replication technique. Methodology: Experimental in vitro study, in which a 3D printed artificial mandibular first molar of piece number 46 with an occlusal class I cavity was prepared to receive the respective occlusal replica. The occlusal matrices (n = 30) and their teeth, will be divided according to the material into 3 groups n=10. Group 1: occlusal replica fabricated with light-curing restorative material. Group 2: occlusal replica made of clear self-curing acrylic, Group 3: occlusal replica made of silicone by condensation reaction. The marginal fit was evaluated using a Canon EOS-Rebel-T7 camera with a 100mm macro lens and MR-14EX- II-Macro-Ring-Lite ring- flash on three surfaces (vestibular, mesial and occlusal) while, the internal fit was evaluated at five different points (Point-A: disto-axial-occlusal, Point-B: disto-axial-pulpal, Mid-pulpal, Point-C: mesio-axial-pulpal, Point-D: mesio-axial-occlusal). Statistical analysis was performed in the Stata-14 program and “the results obtained were analyzed with the ANOVA parametric statistical test and the Kruskal-Wallis” nonparametric statistical test, together with the Bonferroni post hoc analysis to compare the measures. Results: The mean marginal fit in microns existed greater adaptation in the occlusal silicone replicas by condensation reaction with a value of 38.07 ±4.12 µm (p<0.001) followed by clear self-curing acrylic with a value of 51.18±3.97 µm and lastly light-curing resin with a value of 71.34 ±9.65 µm and a (p<0.001). While the average internal fit in microns existed greater adaptation in the occlusal replicas of silicone by condensation reaction with a value of 51.34 ±3.95 µm followed by transparent self-curing acrylic with a value of 66.88 ±4.43 µm and lastly light-curing resin with a value of 105.31 ±18.07 µm and a (p<0.001). Conclusions: With the limitations of this study it can be confirmed that the occlusal replicas elaborated with silicone by condensation reaction presented better properties with respect to marginal and internal fit.