Dentin adhesive superior to copal varnish in preventing microleakage in primary teeth

Microleakage presents a major challenge to the success of all restorations placed in the oral cavity, resulting in postoperative sensitivity, pulpal irritation, and secondary caries formation. The objective of this study was to evaluate the effects of an adhesive cavity liner under amalgam restorations in primary teeth. Sixty class V amalgam restorations were placed on the buccal and/or lingual surfaces of 38 primary molars and canine teeth. A dentin adhesive cavity liner was placed under 20 of the amalgam restorations. Another 20 restorations were lined with copal cavity varnish prior to amalgam condensation. The remaining 20 had no liner. All teeth were thermocycled in 0.5% basic fuschin dye, sectioned, and examined under a stereomicroscope to evaluate microleakage. While all specimens demonstrated leakage around the margins of the restorations, only the teeth with adhesive resin liners prevented leakage into the dentinal walls of the restoration. The copal cavity varnish group displayed microleakage approaching the pulpal chamber, whereas the unlined specimens consistently displayed dye penetration into the pulp chamber. At P < 0.01, the use of an adhesive cavity liner under amalgam restorations in primary teeth resulted in significantly less microleakage.