Clinical evaluation of Class II combined amalgam-composite restorations in primary molars after 6 to 30 months

Composites are claimed to be inappropriate for Class II restoration due to polymerization shrinkage. The present study evaluated the clinical and radiographic appearance of Class II combined amalgam composite restorations in primary molars. Conventional cavities (groups A & B) were restored with 1mm thick amalgam at the cervical floor covered by a posterior composite (Estilux Posterior). In group A Amalgambond was placed between the layers: in group B conventional enamel bond was applied. Vertical increments of Estilux Posterior over enamel bond restored cavities of group C. A fluted carbide bur and Sof-lex discs finished all restorations. Criteria developed by Cvar & Ryge (1971) were used for clinical evaluation of 39 restorations (12, 16 and 11 of Groups A, B and C respectively). No complaints of pain or discomfort were reported during the 6-30 months (mean 15.3) follow-up period. All groups presented excellent surface appearance. Ninety-two percent of group A and 100 percent of groups B & C presented excellent marginal adaptation. Anatomic form was excellent in 92 percent, 8 percent and 100 percent of groups A, B and C respectively. The underlying amalgam was visible through the composite of groups A & B reducing the percentage of excellent ratings of color match to 33 percent and 38 percent respectively, with 9 percent in Group C. This difference was significant (P < 0.02). Secondary caries was observed in two teeth (group A & C). Radiographs presented radiolucent area at the amalgam-composite interface only in one restoration (group A) and one at the tooth-composite interface (group C). Bubbles were found in 6.6 percent of group A; 12.5 percent of group and 64 percent of group C (p < 0.01). This study detected differences between the groups only in color match and the presence of bubbles.