Quantitative analysis of the obturation of oval-shaped canals using thermoplastic techniques.

Background: One of the aim of root canal treatment is filling the root canals in a 3D way. It is not always possible to achieve due to the existence of anatomical variations. The obturation of oval canal usually provides great difficulties. Its complex anatomy can cause obstacles in instrumentation, irrigation and obturation. Aim: The main aim of this study is to quantify the area filled by gutta-percha, the area filled by cement and the area of voids present in oval canals, treated by thermoplastic filling techniques in comparison with the lateral condensation technique and observe the adaptation of the gutta-percha to the anatomy of the oval root canals according to the obturation technique. Material and Methods: 80 mandibular incisors were selected. The teeth were instrumented with Protaper Gold® and divided into 4 groups of 20. Group 1 was filled with Thermafill®; group 2 with GuttaCore®; group 3 with continuous wave vertical condensation and group 4 with the lateral condensation technique. Two horizontal sections were cut at 5mm and 7mm from the apex and they were set in putty silicone. The samples were analyzed with a Leica DMS 1000 digital microscope and processed with Leica Suite for Windows XP. The area of gutta-percha, cement and voids and the percentages, of each one, were calculated. A statistical analysis was performed using the T-Student, ANOVA tests and Kruskal-Wallis tests. Results: All thermoplastic techniques achieved a high percentage of obturation. The percentages of voids in group 4 were the highest. Statistically significant differences were found between thermoplastic techniques compared with lateral condensation. Conclusions: Thermoplastic techniques achieve better adaptation of the gutta-percha in the oval canals and low amount of cement and voids in the middle and coronal thirds respect to the lateral condensation group. Moreover, comparing termoplasthicized techniques among them, continuous wave vertical condensation got the lowest percentage of voids.