A comparison of the marginal adaptation of composite overlays fabricated with silicone and an intraoral scanner

BACKGROUND: Intraoral scanners have been developing during last years. The aim of this study was to know if digital impressions achieve a marginal adaptation in overlays as well as conventional impressions with silicone. MATERIAL AND METHODS: Sixty-two extracted molars were selected. The samples were prepared for MOD overlays. The teeth were divided into two groups (n=31). Group 1: impressions were made with silicone (Express™ Impression, 3M ESPE) and overlays were manufactured with Sinfony composite (3M ESPE) by the laboratory technician. Group 2: impressions were taken with the scanner True Definition (TD, 3M ESPE) and under Lava Ultimate CAD/CAM Restorative composite (3M ESPE) were produced the restorations. Under 32x magnification images of vestibular, lingual, mesial and distal were capture in all the samples. Then the fit of the restorations was evaluated before and after cementation. Data were analysed statistically applying ANOVA and Bonferroni test. RESULTS: The marginal gap was better in TD group before (169,76 ± 54,15 µm) and after (145,16 ± 57,89 µm) cementation than in the silicone group (190,89 ± 58,18 µm) (187,47 ± 81,29 µm). The lowest marginal gap was in oclusal surface and the higher value was in the proximal margin for all the groups. CONCLUSIONS: Digital impressions regarding marginal adaptation achieve better results than conventional impressions. Key words:Composite onlays, overlays, restorative, CAD/CAM, intraoral scanner, silicone impressions, marginal adaptation.