Abstract
Obturation is the process of filling of the space created from the root canal preparation by a material with adequate physical and biological properties to reach the success with the healing. New materials are in the market and need the analysis. The aim of this study will be to evaluate the tissue response to polyethylene tubes filled with MTA Obtura, Endo-CPM-Sealer® e Sealapex®, as well as to evaluate the healing process of dog's teeth with induced periapical lesion, which will be filled with the same materials. Biocompatibility test will use 30 rats, which will receive the tubes with the sealers and an extra empty tube as control. The observation periods will be 7, 15, 30, 60 e 90 days. After each period of time, six animals will be killed and the tubes with the surrounding tissue removed, fixed and processed to the optic microscopic analysis with embedding in glycol methacrylate, cut with 3mm and staining with HE or cut with 10mm and staining with Von Kossa and remaining without staining to be evaluated under polarized light. The criteria will be 0, none or few cells and no reaction; 1, less than 25 cells and mild reaction; 2, between 25-125 cells and moderate reaction; and 3, 125 and more cells and severe reaction. Fibrous capsules were considered to be thin when thickness was <150 ¼m and thick at > 150 ¼m. Necrosis and calcification were recorded as present or absent. An average of value for each material was obtained from the sum of cells counted in 10 separate areas. The data will be evaluated by Kruskal Wallis test. For the evaluation of the healing process of dogs teeth, 8 central incisors, 8 lateral incisors, 8 first pre-molars and 8 second pre-molars of 2 male one year old Beagle dogs. The animals will be anesthetized and coronal access and pulp extirpation performed. The root canals will remain exposed to the oral environment for 6 month to develop the apical lesions. The teeth will be instrumented and divided in groups: Group I -MTA Obtura; Group II - Endo-CPM-Sealer; Group III - Sealapex; Group IV - Control (no filling). After 180 days, the animals will be killed and blocks removed and fixed in 10% buffer formalin to be demineralized in formic-citrate acid. The specimens will be embedded in paraffin, cut with 6 ¼m and the slices staining with HE and Brown and Breen. The histomorphological analysis will include obturation limit, inflammatory infiltrated, apical periodontal ligament, cementum, biologic closure, resorption areas, debris, giant cells, and microorganisms. The results will be analyzed using Kruskal Wallis test.
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