Double-milled CAD-CAM composite resin restorations: A proof-of-concept approach to producing histoanatomic bilaminar restorations

Abstract Bilaminar semi-indirect composite resin computer-aided design and computer-aided manufacturing (CAD-CAM) restorations may represent a noninvasive and straightforward alternative to direct composite resin or indirect porcelain veneers. They involve partial reduction (incisoproximal cutback) of a CAD-CAM composite resin restoration, creating a histoanatomic dentin base, which can then be freehand-layered with an enamel-like composite resin. However, advanced knowledge of dental anatomy is required as well as additional skills to shape the enamel layer to the original shape that was milled. This article describes a possible answer to this dilemma. The restoration was kept attached to the block while doing the histoanatomic cutback. After the bonding of a thicker bulk of enamel to the cutback base, the block was machined again by using the same design. The method relies on the optimal combination of the freehand additive approach and the subtractive automated process.