Coronal microleakage in conservatively restored endodontic access preparations

This study evaluated the coronal microleakage of endodontic access preparations restored with glass ionomer cement (GIC), composite resin (CR), or the "sandwich" (GIC/CR) techniques. The size of access preparation for 32 freshly extracted maxillary premolars was standardized by using a stainless steel template. The teeth were randomly divided into three experimental groups of 10 teeth and one group of two control teeth. Group One: light cured glass ionomer cement, Vitra Bond (3M Dental Products Division, St. Paul, MN). Group Two: composite resin, Silux Plus (3M Dental Products Division, St. Paul, MN). Group Three: "sandwich" technique, consisting of a 3 mm glass ionomer cement base and composite resin restoring the remaining access. The restorative materials were placed incrementally and cured from the facial, lingual and occlusal planes for 20-second intervals. The teeth were thermocycled for 24 hours, immersed in methylene blue dye for 48 hours, and then sectioned to measure dye penetration. This study differed substantially from similar leakage studies. The "sandwich" (GIC/CR) and the composite resin restorations allowed significantly less coronal leakage than the glass ionomer cement restorations. Although not statistically significant, less leakage was measured with the "sandwich" restoration than the composite resin restoration.