The retrieved teeth will be kept in a humid environment until the time of sectioning. Impressions (Aquasil-Dentsply DeTrey GmbH) will be taken, and epoxy replicas (Epokwick resin, Lake Bluff, IL 60044) of the proximal surfaces will be prepared and gold plated. The micromorphology of the margins will be evaluated by SEM (Jeol JSM 35), and defects at the tooth-restoration interface will be assessed at the cervical proximal margins (buccal and lingual). These defects will be classified according to the fraction of margin length showing gaps wider than 10 microns, as described by Fuks & others 26: