OR07 - Quantitative Analysis of the Microhardness of Human Root Dentin Following Root Resection and Root Surface Treatment With Er;Cr:YSGG Laser: a Pilot Study

Objective: Empirical case reports raise the need to consider laser in future protocols. The purpose of this study was aimed at evaluating the effect of peri-apical micro-surgical protocols, with and without laser treatment, on the microhardness of human dentin.

Methods: Ten matched pairs of human extracted teeth were kept in saline and divided into 2 groups. All teeth were treated following contemporary endodontic techniques. In group 1, apicoectomy was performed using a Lindemann bur. Resected roots were irrigated with chlorhexidine and surface-treated with citric acid. In group 2, apicoectomy and root surface treatment were performed using Er;Cr:YSGG at 6W, 25 Hz with air and water. MZ5 and side-firing tips were used as in a clinical environment. The treated resected root surfaces were viewed under SEM for descriptive purposes. They were subsequently sectioned, embedded in epoxy resin and polished. All specimens were subjected to a Vickers hardness tester and microhardness values were recorded to compare laser-treated specimens to those treated with conventional means.

Results: Mean microhardness values of laser-treated specimens were 198 when compared to 67 for specimens that were not treated with laser. A paired t-test found the differences in microhardness values to be statistically significant (p < 0.05). Laser resection and root surface treatment resulted in significantly increased microhardness of exposed dentin as well as sealing of the dentinal tubules. The affected areas averaged 30 microns in depth.

Conclusion: The findings of this study lead the way onto a possible paradigm shift and pave the way for future experiments aimed at strengthening root dentin during endodontic procedures.