Comparison of Two Techniques for Selection of Master Gutta-Percha Cone Using Micro-Computed Tomography

Abstract

This study used micro-computed tomography (micro-CT) to evaluate the fit of the master gutta-percha cone at time of cone fit, gutta-percha volume in the filling material, and the filling material volume in relation to the canal at the apical limit of the working length. Root canals of 20 maxillary central incisors were prepared with rotary instruments and distributed into two groups (n=10). The gutta-percha cone tip was either plasticized (apical thermal impression technique - ATI) or not (conventional technique - CT), and its apical fit was checked. The apical 1 mm of working length was examined with a micro-CT, canals were filled with gutta-percha and sealer, and new micro-CT scans were obtained. In CT, gutta-percha filled 35.83 ± 15.05% of the canal at cone selection and 38.72 ± 11.64% after filling. In ATI, these values were 23.14 ± 7.74% and 26.98 ± 20.40%, respectively. Gutta-percha volume in the filling material, and filling material volume in relation to the canal were, respectively, 61.28 ± 11.64% and 87.76 ± 9.98% for CT, and 73.00 ± 20.41% and 89.96 ± 9.08% for ATI. No significant difference was found between cone selection and after canal filling, for either CT (p=0.593) or ATI (p=0.4975). The techniques did not differ significantly with respect to gutta-percha volume in the filling material (p=0.132) and filling material volume in relation to the canal (p=0.612). An ideal fit of the master gutta-percha cone at working length was not achieved regardless of the cone selection technique, and the material-filled area was similar for both techniques.

Quantification of the tug-back by measuring the pulling force and micro computed tomographic evaluation

“…Various experimental methods have been used to assess the quality of root canal sealing, such as fluid filtration [ 1 ], bond strength test [ 21 22 ], photo-micrographic analysis [ 2 5 16 23 24 25 ] and µCT imaging [ 4 13 26 27 ]. Above all, µCT imaging and stereoscopic microscopic methods allow the assessment of cross-sectional images of the space occupied by GP, sealer, and void.…”

“…Three-dimensional obturation of the radicular space is essential for long-term success [ 3 ]. Regardless of the obturation technique used, it is important to select a master cone that is well adapted to the canal for a fluid-tight apical seal [ 4 ]. Previous studies reported that root canal obturation with a matched-taper single cone provided a better apical seal as compared to other master cones [ 2 5 ].…”