Connective Tissue Reaction of Rats to a New Zinc-Oxide-Eugenol Endodontic Sealer

The aim of this study was to evaluate the biocompatibility in rat subcutaneous connective tissue of a new zinc oxide endodontic sealer (Endomethasone N) compared to those provided by Endofill and Sealer 26. Polyethylene tubes containing the test materials were implanted into dorsal subcutaneous connective tissue of Wistar albino rats. After 7 and 42 days, the implants with the surrounding tissue were collected, fixed, and processed for histologic evaluation. Sections were evaluated for the presence of inflammatory cells (poly or monomorfonuclear), blood vessels, necrosis area, and thickness of fibrous capsule. Comparisons between groups and time-periods were performed with Kruskal-Wallis and Mann-Whitney U non-parametric tests for 5% significance level. No differences in the biocompatibility patterns among the materials for the 2 experimental periods were observed. Independently of the sealer, the tissue behavior showed a tendency to decrease the irritation effect over time. It can be concluded that all sealers are irritant, but its toxicity decreased with time. Endomethasone N showed biocompatible characteristics comparable with those provided by Endofill and Sealer 26. Microsc. Res. Tech. 76:1292-1296, 2013. (c) 2013 Wiley Periodicals, Inc.76121292129

Influence of apical enlargement in cleaning and extrusion in canals with mild and moderate curvatures

Optical microscopy and morphometric analysis were used in this study to evaluate, in vitro, the cleaning of the apical region in root canals with mild or moderate curvatures subjected to biomechanical preparation with a rotary system, as well as to assess the amount of extruded material to the periapical area. Lateral incisors (n = 32), 16 with curvature angles smaller or equal to 10° (GI) and 16 between 11° and 25° angles (GII) were submitted to Hero 642 rotary instrumentation with different surgical diameters: (A) 30.02 and (B) 45.02. Irrigation was performed at each change of instrument with 5 mL of ultrapure Milli-Q water and the extruded material through the apical foramen was collected. Root cross-sections were subjected to histological analysis by optical microscopy (×40) and the images were evaluated morphometrically using the Image Tool software. Quantification of the extruded material was performed by weighing after liquid evaporation. ANOVA showed no statistically significant differences (p>0.05) among the groups with respect to the procedures used to clean the apical region. Considering the amount of extruded material, the Tukey's HSD showed that canals with mild curvature prepared with the 45.02 surgical diameter showed significantly higher values (p0.05). In conclusion, the effect of cleaning the apical region did not differ in the groups, considering root curvature and the surgical diameter of instruments used for apical preparation. The amount of extruded material was greater in canals with mild curvature that were prepared with the 45.02 surgical instrument diameter.Brazilian Dental Association, Uberlândia, MGUniversity of Ribeirão Preto, Ribeirão Preto, SPAraraquara Dental School UNESP Univ. Estadual Paulista, Araraquara, SPNova Southeastern University, Fort Lauderdale, FLAraraquara Dental School UNESP Univ. Estadual Paulista, Araraquara, S