Enamel Margin Preservation and Repair Technique

Objectives: Evaluate the enamel condition after the Enamel Margin Preservation and Repair Technique (EMPT) by determination of the formation of enamel micro-cracks (EMC) after occlusal reduction, following the removal of dentinal support and bonding composite resin to unsupported enamel (UE). Subgingival margins (SGM) complicate isolation, final impression, cementation and finishing. EMPT, prevents SGM by removing infected dentin and preserving healthy supra-gingival enamel.
Methods: 15 molars preserved in 5% NaOCl and H₂O, received onlay preparations. Followed by the dentin removal at the DEJ using a diamond, leaving an unsupported enamel wall, 1.5mm in height. Group 1 had a 1.5mm, G2 a 1mm and G3 a 0.5mm thick UE. Restorations were made with Majesty Flow and Majesty ES 2 using Clearfil SE Protect as bonding agent, using a protocol to minimize polymerization shrinkage. EMCs were discovered after application of caries detector (Kuraray) for 1 minute using high magnification photography, after occlusal reduction, and after enamel repair with composite resin. Data were analyzed via Kruskal-Wallis ANOVA (α=0.05).
Results: See table.
Results show, no additional EMC after the EMPT in groups 1 and 2. Group 3 had one additional EMC, from the occlusal reduction baseline. There was no statistically significant difference between the groups (p=0.221)
Conclusions: The findings suggest that a supra-gingival enamel margin can be preserved and repaired using EMPT. Having 1mm or more of enamel thickness appears to be more predictable. Future investigations should be performed to evaluate the effects of thermal and load cycling.