The choice of an irrigating solution for use in infected root canals requires previous knowledge of the microorganisms responsible for the infectious process as well as the properties of different irrigating solutions. Complex internal anatomy, host defenses and microorganism virulence are important factors in the treatment of teeth with asymptomatic apical periodontitis. Irrigating solutions must have expressive antimicrobial action and tissue dissolution capacity. Sodium hypochlorite is the most used irrigating solution in endodontics, because its mechanism of action causes biosynthetic alterations in cellular metabolism and phospholipid destruction, formation of chloramines that interfere in cellular metabolism, oxidative action with irreversible enzymatic inactivation in bacteria, and lipid and fatty acid degradation. The aim of this work is to discuss the mechanism of action of sodium hypochlorite based on its antimicrobial and physico-chemical properties.

Under ultrasonic agitation, sodium hypochlorite associated with EDTAC removed the smear layer from root canal walls, whereas irrigation with distilled water or 1.0% sodium hypochlorite alone did not remove smear layer.

An increase in frequency, independent of power settings, of the lasers used in this study increased adhesion of an epoxy-based root canal sealer.

No abstract

This in vitro study evaluated the effect of Er:YAG laser on adhesion to human dentin of Grossman, Endomethasone, N-Rickert, and Sealer 26 root canal sealers. The crowns of 40 human molars were cut on the occlusal side until a flat dentin surface was obtained. The teeth were divided into two groups: group 1, no laser application; and group 2, irradiation with Er:YAG laser (KaVo Key Laser 2; 11 mm focal distance, perpendicular to the dentin surface, 4 Hz frequency, 200 mJ energy, 62 J total energy and 313 pulses, 1-min application time, and 2.25 W power). Five samples were tested for each sealer and each group. An Instron universal testing machine was used for the adhesion test. Sealer 26 showed the best adhesion both with and without laser application (p < 0.01). Grossman and N-Rickert sealers had intermediate values, and Endomethasone had the worst adhesion. Application of Er:YAG laser did not alter the adhesion of Grossman, N-Rickert, or Endomethasone sealers. However, laser application increased the adhesion of Sealer 26. The epoxy resin-based root canal sealer (Sealer 26) adhered better to dentin prepared with and without Er:YAG laser than the zinc oxide/eugenol-based sealers (Endomethasone, N-Rickert, and Grossman).

When considering different output powers and delivery modes our results showed that changes varied from smear layer removal to dentine fusion.

No abstract

No abstract