The purpose of this study was to observe the influence of coronal leakage on the behavior of periapical tissues after root canal filling and post space preparation. Forty root canals of dogs' teeth were instrumented and filled by the lateral condensation technique with gutta percha points and the cements Sealer 26 and Roth. After post space preparation, the remaining filling material was either protected or not protected with a plug of the temporary cement Lumicon. After root canal exposition to the oral environment for 90 days, the animals were killed and specimens were removed and prepared for histomorphological analysis. The Brown and Brenn technique showed 70% of cases with microorganism leakage for Roth cement, and 20% with Sealer 26. When a plug of Lumicon was employed, there was 30% leakage for Roth cement and 0% for Sealer 26. A chronic inflammatory reaction was more frequently observed with Roth cement than with Sealer 26. It was concluded that a plug of Lumicon was efficient in controlling microorganism coronal leakage (p = 0.05), and that Sealer 26 was more biocompatible and sealed root canals better than Roth sealer (p = 0.01).

The objective of this research was to determine if gutta-percha points with calcium hydroxide [Ca(OH) 2 ] improve the apical seal after root canal filling and if the master point does it alone. Human single recently extracted teeth were biomechanically prepared and the root canals filled by the lateral condensation technique with ZOE and gutta-percha points, with or without calcium hydroxide. The teeth were placed into a 2% methylene blue solution in a vacuum environment for 24 h after which they were processed for stereomicroscope evaluation. Better results were observed with the teeth filled with gutta-percha points with calcium hydroxide (p=0.01). We conclude that these new points make a better apical seal and that these results can also be obtained with the calcium hydroxide master point associated with regular ones (p=0.05).