Retreatment using a modified-tip instrument.

The purpose of this article is to present a technique in which a modified file is used with reaming motion and apical pressure in retreatment cases.

Quantity of apical extruded material and efficiency of five different methods of removing gutta-percha and sealer from root canals--"in vitro" evaluation.

The objective of this study was the comparison, in three clinical situations, of five different methods of removing gutta-percha and sealer from root canals necessitating endodontic retreatment "in vitro". In the first method only hand instruments (files) were used; in the second and third Sonic and Ultrasonic devices were used respectively, and in the fourth and fifth methods Sonic and Ultrasonic devices were used with hand instruments. In order to evaluate these methods, the time required to remove the filling material, the amount of debris remaining in the canals after the deobstruction and the quantity of substances extruded beyond the apex were investigated. The results showed that while the hand method and the combined methods had no statistically significant differences in respect of time spent, the amount of remaining debris was greater in the combined method. On the other hand, the sonic and ultrasonic techniques demonstrated that more time was required for deobstruction when compared to the hand instruments technique, besides a greater quantity of remaining debris in the canal walls. The extruded material beyond the apex was considered non significant in all methods.

[Comparative study of three materials used for filling perforations made during intra-radicular dowel preparation]. / Estudo comparativo entre três materiais utilizados no preenchimento das perfurações provocadas durante o preparo para retentor intra-radicular.

Fifteen extracted human teeth were used in which after root canal treatment post preparation was made. During this preparation the middle third of the roots was perforated intencionally. These perforations were filled with three different materials: Silver amalgam, Lumicon, N-Richert Cement, associated in five groups (Lumicon; Lumicon Plus Silver Amalgam; N-Rickert Cement; N-Rickert Cement Plus Amalgam; Silver Amalgam). After this, the teeth were prepared for S.E.M. analysis. The photomicrographics were analysed by 20 observators with the purpose to the determine the filling of the material on the borders of the cavity. The best results were achieved with Lumicon Plus Silver Amalgam.