MICROLEAKAGE OF CLASS-2 SUPERBOND-LINED COMPOSITE RESTORATIONS WITH AND WITHOUT A CERVICAL AMALGAM BASE

The purposes of the present study were: 1) to assess the microleakage at the cervical margin of Superbond-lined composite restorations with and without a cervical amalgam base and compare the results to cervica l margins of composite restorations lined with Scotchbond 2, and 2) to compare the quality of the occlusal margins of Superbond-lined P-50 r estorations with those bonded with Scotchbond 2. Forty-eight class 2 c avities were prepared in extracted or exfoliated primary molars. The t eeth were randomly divided into three groups and restored as follows: Group A, amalgam + Superbond + P-50 (sandwich); Group B, Superbond + P -50; Group C, Scotchbond 2 + P-50 (control). Marginal leakage was asse ssed by the degree of dye penetration on sections of the restored teet h. The occlusal margins presented no or minimal leakage (degrees 0 and 1) in 53% of Group A restorations, 60% of Group B, and 44% of Group C . These differences were not statistically significant (P > 0.05). The cervical margins showed moderate to severe dye penetration (degrees 2 and 3) in 94% of Group A, 47% of Group B, and 87% of Group C. These d ifferences were statistically significant (P < 0.05). The amalgam/ Sup erbond/composite interface exhibited no leakage in 70% of the restorat ions. Although marginal leakage was not completely eliminated, Superbo nd exhibited significantly less leakage (P < 0.05) at the cervical mar gins than Scotchbond 2 or amalgam with Superbond.