Resumo

PORCIUNCULA, Dilene et al. Evaluation of three instrumentation techniques with different apical diameters on smear layer formation. RFO UPF [online]. 2015, vol.20, n.1, pp. 23-27. ISSN 1413-4012.

Objective: to evaluate the effects of different instrumentations on smear layer formation in the apical third of 90 mesio-buccal roots of upper molars by scanning electron microscopy (SEM). Materials and method: three groups were formed based on techniques used: hand instrumentation, K3 rotary system, and NSK reciprocating handpiece. The groups were subdivided by three according to the size of the apical diameter: #30, #35 or #40 files. After preparation, roots were transversely sectioned, separating the apical thirds of the remaining roots; these thirds were split into halves and prepared for SEM. The smear layer formation on the surface of the root canal and in dentinal tubules was scored at 1,000× magnification. Data were analyzed using the Kruskal- Wallis test and Dunn's test (p < 0.05). Results: the increase of the diameter in apical preparation had no influence on smear layer formation on dentinal walls. Conclusion: regardless of the technique and apical diameters applied for preparation, no dentinal wall free of smear layer was observed.

Palavras-chave : Endodontics.; Root canal preparation.; Smear layer..