Influência do timing da colocação de retentor intra-radicular no selamento apical

Objective: To evaluate the integrity of the apical seal in root filled teeth following immediate post space preparation and after eight days.Methods: Forty extracted single-rooted human teeth were instrumented and filled, using lateral condensation technique, with gutta-percha and Sealapex® sealer (Kerr-Sybron, Scafati, Italy). The teeth were randomly assigned to four groups: group I (GI) with seventeen teeth (immediate post space preparation), seventeen in group II (GII) (delayed post space preparation) and three teeth in each control group, group III (GIII) positivecontrol and group IV (GIV) negative control. In GI and GII, the post space was prepared with ProTaper Universal® retreatment files (Dentsply/Maillefer, Ballaigues, Switzerland). After the post space preparation, all specimens were coated, except for two apical millimeters, immersed inmethylene-blue dye for eight days, and then sectioned longitudinally. The extent of staining was examined under a stereomicroscope. Results: In GI there was an average apical leakage of 7,42 mm, while in GII it was 6,82 mm. There were no statistically significant differences between groups I and II (p>0.05). Conclusion: The timing of post space preparation, in teeth filled with Sealapex® sealer (Kerr-Sybron, Scafati, Italy), did not affect the apical sealing ability.(AU) Objetivo: Avaliar o selamento apical em dentes desobturados imediatamente apos a obturacao radicular e desobturados oito dias depois, para a colocacao de retentor intra-radicular. Metodos: Quarenta dentes unirradiculares, foram instrumentados manualmente e obturados pela tecnica de condensacao lateral com cones de gutaperchae cimento Sealapex® (Kerr-Sybron, Scafati, Italy). Foram aleatoriamente distribuidos em 4 grupos. Grupo I (GI) 17 dentes - desobturacaoimediata; Grupo II (GII) 17 dentes - desobturacao tardia; Grupo III (GIII) 3 dentes - controle positivo; Grupo IV (GIV) 3 dentes - controle negativo.Para a desobturacao (GI e GII) foram utilizados instrumentos mecanizados de retratamento ProTaper Universal® (Dentsply/Maillefer, Ballaigues,Switzerland). Apos desobturacao, os dentes foram impermeabilizados com esmalte, exceto nos 2 milimetros apicais, foram imersos em solucaode azul-de-metileno durante 8 dias e seccionados longitudinalmente. Com o auxilio de uma lupa ?Wild Makroskop M420? foi realizada a leitura da infiltracao. Resultados: No GI, obteve-se infiltracao apical media de 7,42 mm e no GII de 6,82 mm. Estas diferencas nao foram estatisticamente significativas (p>0,05). Conclusao: O momento de desobturacao para a colocacao de retentores intra-radiculares, de dentes obturados com cimento Sealapex® (Kerr-Sybron, Scafati, Italy), nao afetou o selamento apical.(AU)