Histomorphometric analysis of remnainder dentin after prepare with Gates-Glidden burs

Introduction: The cervical preparation of the roots is a procedure very used in the endodontic therapy. The use of burs during the accomplishment of this procedure diminishes the dentin thickness fragiling the dental remnainder. Objective: The aim of this study was to achieve histomorfometric analysis of the dentin thickness of the distal wall of mesio buccal canal (MB) of the first mandibular molar after using Gates Glidden burs 1,2,3. Methods: Twenty MB canal root had were instrumented in the crown-down direction with Kerr files numbers 35-30-25-20-15. After the instrumentation, the teeth had been divided in 2 groups: control and experimental. The teeth of control group did not receive any treatment after instrumentation. MB canals of group experimental was prepared with Gates Glidden burs 1,2,3. After that, the teeth had been descalcified in 5% acid nitric and had their mesial roots separated just below of bifurcation. The cervical root segments were embedded in paraffin, then out cross sectionally in 5ìm thick slices which were stained with Mallory Trichrome. The sections were analysed under light microscope with the HL Image software, yelding measurements of the distal wall of the mesio buccal canal. Results: The statistical analysis of the data (t-Student test, p<0,0001) it showed to significant difference of dentin thickness between control (average= 783µm) and experimental (average= 389µm) groups. Conclusion: The results indicate that the use of Gates Glidden burns promotes significant wear in the distal wall of mesio buccal canal root of first mandibular molar reducing the remnainder dentin.