Adhesive Restorations in the Posterior Area with Subgingival Cervical Margins: New Classification and Differentiated Treatment Approach

The aim of this article is to analyze some of the issues related to the adhesive restoration of teeth with deep cervical and/or subgingival margins in the posterior area. Three different problems tend to occur during restoration: loss of dental substance, detection of subgingival cervical margins, and dentin sealing of the cervical margins. These conditions, together with the presence of medium/large-sized cavities associated with cuspal involvement and absence of cervical enamel, are indications for indirect adhesive restorations. Subgingival margins are associated with biological and technical problems such as difficulty in isolating the working field with a dental dam, adhesion procedures, impression taking, and final positioning of the restoration itself. A new classification is suggested based on two clinical parameters: 1) a technicaloperative parameter (possibility of correct isolation through the dental dam) and 2) a biological parameter (depending on the biologic width). Three different clinical situations and three different therapeutic approaches are identified (1st, 2nd, and 3rd, respectively): coronal relocation of the margin, surgical exposure of the margin, and clinical crown lengthening. The latter is associated with three further operative sequences: immediate, early, or delayed impression taking. The different therapeutic options are described and illustrated by several clinical cases. The surgical-restorative approach, whereby surgery is strictly associated with buildup, onlay preparation, and impression taking is particularly interesting. The restoration is cemented after only 1 week. This approach makes it possible to speed up the therapy by eliminating the intermediate phases associated with positioning the provisional restorations, and with fast and efficient healing of the soft marginal tissue.