Aid of Magnification Devices in Post Space Preparation

Objective: To perform a scanning electron microscope (SEM) analysis of canal dentin surfaces after post space preparation with the aid of two different magnification devices: dental loupes or operating microscope. Cleanliness of post space walls was the outcome variable evaluated. Methods: Twenty single-rooted human teeth (18 canines and 2 premolars) were selected. Root canals were cleaned, shaped using Ni-Ti instruments (Protaper, Maillefer) and filled with warm gutta-percha. Samples were divided into two groups, A and B (n=10). In group A, post space preparation was conducted using a dental microscope (magnification of x6 – x40), while in group B the same operator wore galilean loupes (magnification of 2.5x). Post space was prepared suitable for a prefabricated double-tapered fiber post. Gutta-percha filling was removed with a sequence of low-speed post drills; root canal walls were also cleaned using a dental excavator, tips for ultrasound, and microbrush. Samples were prepared for SEM analysis. Canal walls were observed and amount of sealer/gutta-percha remnants were rated using the following score system: 0 - no debris were present; 1 - few debris with largest diameter < 20µm; 2 - large amounts of debris. Visibility of open tubules was evaluated using an analogous 3-step scale. Mean debris and open tubules scores were calculated; Kruskal-Wallis and Mann-Whitney U tests were performed (P < 0.05). Results: Mean debris scores found at three depth levels of post space were: group A - Coronal 0.68; Medium 1.40; Apical 1.76; group B - Coronal 1.12; Medium 1.58; Apical 1.96. Statistically significant differences (P < 0.05) were found at coronal and apical levels, with better debris and open tubules scores for group A. Conclusion: The use of operating microscope let achive a better canal cleanliness, restricted to coronal and apical areas of post space.