Microleakage of Tetric Ceram/Excite and Ariston pHc/Ariston Liner

Purpose: To investigate the microleakage associated with a hybrid resin-bas ed composite, Tetric Ceram, bonded with the single component dentin bonding agent Excite and Ariston pHc bonded with Ariston Liner. Ariston pHc bonded with Excite and Tetric Ceram bonded with Prime and Bond NT were used as co ntrols. Materials and Methods: Twenty-four extracted human premolars and mo lars were randomly assigned to four groups. Group 1: cavities were bonded w ith Excite and filled with Tetric Ceram. Group 2: cavities were bonded with Ariston Liner and filled with Ariston pHc. Group 3, control: cavities were bonded with Prime & Bond NT and filled with Tetric Ceram. Group 4, control : cavities were bonded Excite and filled with Ariston pHc. Cavities were cu t in both the buccal and lingual surfaces. Half of each preparation was in enamel and the other was in cementum/dentin. The teeth were thermocycled at 15 degreesC for 2 s, 35 degreesC for 28 s and 45 degreesC for 2 s for 5000 cycles after which the restorations were examined microscopically for leak age using procion brilliant red as a marker. SEM microphotographs were prep ared from dye-labeled and non dye-labeled areas to illustrate the micromorp hology of the systems. Results: None of the groups showed microleakage at t he enamel margins. All groups showed microleakage at the gingival margins. At the gingival margin there was a significant difference between the group s (Kruskal-Wallis ANOVA, P= 0.1111.). Ariston pHc/Ariston Liner showed sign ificantly lower microleakage scores than the other groups (Dunn's Multiple Comparison test). SEM showed that in non-dye labeled areas, Ariston pHc/Ari ston Liner was in close apposition to the deeper dental tissues. The "total etch" technique resulted in a zone of demineralization. Debonding occurred at or near the top of the hybrid layer in > 95% of specimens.