Location and angulation of curvatures of mesiobucal canals of mandibular molars debrided by three endodontic techniques

Abstract

The aim of this study was to assess the correlation between the degree of angulation and the position of root curvatures and their influence on the comparative results between the performances of the Progressive, Staged and Serial Preparation Techniques. The mesiobucal canals of 70 extracted mandibular molars were filled with a radiological contrast of 100% Barium sulphate and radiographed with a direct digital radiographic system, in an apparatus that guarantees that the samples remain in the same spatial position at all times. The images were then analyzed in the Coreldraw 10 program (MicroSafe, RJ, Brasil) in accordance with two criteria: the methods of Berbert, Nishiyama(1) (1994) and Schneider11 (1971) to determine the position and the angle of the root curvatures, respectively. Initially, the possibility of correlation between these two variables was studied. The teeth were then selected according to angulation (greater than 25 degrees) and position of root curvatures (cervical, median and apical) in order to perform the endodontic techniques. After preparation, the samples were radiographed again and the images were superimposed in order to compare the pre- and post-operative areas. The difference between them showed the percentage of widening for each technique. The results showed that there was no correlation between the angulations and the root curvature positions, and that the different positions did not interfere in the performance of the techniques. The Progressive Preparation technique produced the highest widening values for all the groups, irrespective of the root curvature position.

Comparison of the effects of TripleGates and Gates-Glidden burs on cervical dentin thickness and root canal area by using cone beam computed tomography

“…In this study it was observed that the wear of the distal wall (Risk Zone) of the mesial canals of mandibular molars was significantly greater than the wear of the mesial wall (Safety Zone) (p<0.05), with no differences between the wear promoted between drills compared. Similar results were observed previously 4 , 6 , 17 . Both GG and TP left an average remaining dentin thickness of approximately 0.6 mm in the distal wall ( Table 2 ).…”

“…Preflaring of the cervical third decreases the tension of manual and rotary instruments during apical instrumentation by eliminating dentin projections 4 , and also provides greater reliability when defining the working length and the apical gauging 12 . Moreover, when prepares with NiTi instruments without the pre-enlargement in the cervical region with stainless steel instruments, there is a greater action of the NiTi instruments on the wall of the furcation, reducing the dentin thickness to values below 0.5 mm 24 .…”

“…The furcation area of the first mandibular molars, sectioned at a point located between 2 and 3 mm below the furcation of the roots, presented a concave aspect in 100% of the mesial roots 3 . Several authors have described an area 3 to 4 mm below the entrance of the canals to be the most sensitive location for the perforation of mesial molar roots after the use of rotary instruments 4 , 6 , 12 . Based on these results, the present study opted to evaluate and measure the dentin thickness 3 mm below the furcation of the roots.…”

Effects of Gates-Glidden, LA Axxess and orifice shaper burs on the cervical dentin thickness and root canal area of mandibular molars

“…Preflaring of the cervical third decreases the tension of manual and rotary instruments during apical instrumentation by eliminating dentin projections (13), and also provides greater reliability when defining the working length and the apical gauging (4,5,14). Several methodologies have been employed to assess the effect of endodontic instruments on dentin wall thickness such as: resin blocks (15), scanning electron microscopy (16), radiography (17) and computer tomography (18,19).…”

Variações anatômicas que interferem no tratamento endodôntico - revisão da literatura

“…É imprescindível que os profissionais que trabalham com Endodontia possuam adequados conhecimentos sobre a anatomia interna dos dentes para permitir o planejamento dos procedimentos endodônticos, que se relacionam com a identificação dos diferentes aspectos observados através de recursos imaginológicos, incluindo as variações anatômicas (MATTUELLA et al, 2005;CONSTANTE et al, 2007a;CONSTANTE et al, 2007b;ESTRELA et al, 2008). O domínio desse conhecimento pode evitar erros durante a identificação, instrumentação e obturação dos canais radiculares (MATTUELLA et al, 2005).…”