Different Methods for Inlay Production: Effect on Internal and Marginal Adaptation, Adjustment Time, and Contact Point

SUMMARY The aim of this study was to evaluate the effect of different production methods of resin and ceramic inlays on marginal and internal adaptation, adjustment time, and proximal contacts. Forty premolars were selected, embedded (their roots), and prepared to receive inlays that were made as follows (n=10): LaRe—digital impression with a Lava C.O.S. scanner, followed by milling of Lava Ultimate block (composite resin) in a milling center; CeRe—digital impression with a Cerec 3D Bluecam scanner, followed by milling of Lava Ultimate block in Cerec; CeDis—digital impression with a Cerec 3D Bluecam scanner, followed by milling of IPS e.max CAD block (lithium disilicate) in Cerec; and PresDis—impression with polyvinyl siloxane, inlay made using the lost wax technique and IPS e.max Press pressed ceramic (lithium disilicate). Marginal and internal adaptations were measured using the replica technique. The inlay adjustments were performed using diamond burs in a contra-angle hand piece, and the time for adjustment was recorded using a timer, in seconds. The tightness of the proximal contact was measured using standardized metal blades. The statistical analyses for marginal fit data showed that at the cervical edge, CeDis (177.8 μm) had greater misfit than CeRe (116.7 μm), while all the groups had similar adaptation at the occlusal edge. The groups had similar internal fit at the pulpal wall, while LaRe (104.7 μm) > CeDis (66.7 μm) = CeRe (76.7 μm) at the axial wall. The groups restored with lithium disilicate ceramic took more time for adjustment when compared to the resin restorative material. The lowest proximal contact, in micrometers, was seen in the CeRe group (8.8 μm).