Resumo

MAIA FILHO, Etevaldo Matos et al. Effect of different types of coronal flaring on the circularity and area of mandibular first molar mesial root canals. RGO, Rev. gaúch. odontol. (Online) [online]. 2013, vol.61, n.2, pp. 193-197. ISSN 1981-8637.

Objective This study assessed the effect of coronal flaring with the Gates-Glidden (GG) bur, La Axxess (LA) bur, and SX file on the area, circularity, and residual dentin thickness in the furcal direction of mandibular first molar root canals. Methods The mesiolingual and mesiobuccal canals of twenty-one mandibular first molars were instrumented. The teeth were embedded in acrylic resin, and after coronal flaring, the roots were cut perpendicularly to their long axis 2 mm below the cementoenamel junction. The sections were photographed before and after flaring with GG bur no. 3, LA bur no. 1 and SX file. The area, circularity, and residual dentin thickness in the furcal direction were calculated by the software Image J. Results Before instrumentation, the canals had a mean area of 0.56mm2±0.37 and mean circularity of 0.31±0.08. After flaring with the GG, SX and LA instruments, the mean areas were 0.68mm2±0.20, 0.64mm2±0.18, and 0.85 mm2±0.23, respectively; and the mean circularities were 0.39±0.08, 0.35±0.08, and 0.39±0.06, respectively. The areas achieved with the LA bur and SX file were statistically different (p<0.05). The final circularities (p>0.05) and residual dentin thicknesses in the furcal direction (p>0.05) did not differ between the groups. Conclusion Coronal flaring with the study instruments was safe. The SX file achieved the smallest area. Circularity and residual dentin thickness in the furcal direction were not affected by the different instruments. No instrument was capable of achieving a circularity greater than 0.5.

Palavras-chave : Dental pulp cavity.; Endodontics.; Instrumentation.; Cavidade pulpar..