Chairside CAD/CAM Composite Onlays for the Restoration Of Primary Molars

Abstract

After pulp therapy or with multi-surface caries in primary molars, pre-formed stainless steel crowns are usually placed to ensure tooth longevity. Esthetic alternatives, such as zirconia crowns, have been proposed, but they are invasive. Here we describe two cases of chairside computer-aided design and computer-aided manufacturing (CAD/CAM) technology used to treat extended and/or deep caries on primary molars. A powder-free chairside CAD/CAM system, a milling unit and machinable high-performance composite blocks were used. The tooth preparation consisted of preparing the cavity without undercut, to have supra-gingival margins whenever possible, occlusal reduction of thin walls, and proximal box finishing by ultrasonic tips. After the optical impression, the virtual onlay was designed and adapted (from the morphology of a first permanent molar), then chairside-manufactured out of a composite block and bonded by using a self-adhesive resin cement. This technique combines minimally invasive treatment; high strength, biocompatible and aesthetic material; no gingival trauma; easy execution; and patient and parent satisfaction. However, the equipment is quite expensive and the software still does not include the morphology of primary teeth.