No abstract

Both lasers promote morphologic changes and debris removal. These alterations of the dentin surface appeared to be more evident in the Nd:YAG laser group, but the diode laser group showed more uniform changes.

We concluded that the combination of the Nd:YAG laser and AH Plus showed the best results.

The purpose of this study was to compare, in vitro, by means of computerized analysis of digital radiographic images, the anatomic alterations produced in the mandibular molar tooth dentinal walls of mesiobucal canals with severe curvature by three different endodontic techniques: Progressive Preparation, Staged and Serial Preparation. A selection was made of 45 extracted, human, mandibular molars, with root curvatures greater than 25 degrees. They were divided into three groups for every technique studied, which were then sub-divided into three sub-groups in accordance with the position of the curvature along the root: cervical, median or apical. After access surgery and tooth length determination, the canals were filled with 100% Barium Sulphate radiological contrast and the teeth were then radiographed with a direct digital radiography system, using a special apparatus capable of keeping the samples in the same spatial position during the different radiographic takes. After the above-mentioned endodontic techniques had been performed, the teeth were again filled with Barium sulphate and were also radiographed under the same previously mentioned conditions. The pre- and post-operative digital images were then analyzed in two computerized programs, AutoCAD 2004 and CorelDraw 10, to assess, respectively, the areas and the horizontal alterations which occurred in the internal and external walls of the root canals. The results indicated that although no significant differences among the techniques were shown in the statistical analysis, in a descriptive analysis the Progressive Preparation technique was shown to be more regular, uniform and effective.

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.