Efeito da irradiação do laser diodo 980 nm na microdureza da dentina radicular tratada previamente com diferentes soluções irrigantes / Effect of irradiation with diode laser (980 nm) on microhardness of root dentin previously treated with different irrigating solutions

AUTOR(ES)

Raqueli Viapiana

DATA DE PUBLICAÇÃO

2009

RESUMO

The purpose of the present study was to evaluate, in vitro, the effect of 980 nm diode laser irradiation, in potencies of 1.5 and 3.0 W and 100 Hz frequency, on microhardness of radicular dentine in different depths. Seventy two roots of human canines were instrumented and randomly distributed into 3 groups (n=24), according to the irrigating solution used in the biomechanical preparation: GI - distilled and deionized ultrapure Mili Q water (control); GII - 1% NaOCl and GIII - 1% NaOCl + 17% EDTA. Each group was subdivided (n=8) according to the laser potency: A- no irradiation (control); B 1.5 W and C 3.0 W. The laser application inside the root canals was performed with helical movements for 20 seconds. Roots were sectioned in slices and the fragment corresponding to the medium third was polished and submitted to the microhardness test (Knoop) using load cell of 25 g for 10 seconds, varying the distance from the canal lumen toward the external root surface (30, 90, 150 and 300 μm). ANOVA showed no statistically significant difference (p>0.05) among the irrigating solutions. Tukey-Kramer test showed that the microhardness values (KHN) obtained in the irradiated groups with 1.5 W (49.711.2) and 3.0 W (50.611.9) were statistically similar between themselves (p>0.05) and statistically different (p<0.05) from the group no irradiated (control) (45.09.7), which presented the inferior microhardness values. The higher microhardness values were obtained at 150 μm (49.211.0) and 300 μm (52.311.3), statistically similar between themselves (p>0.05) and statistically different (p<0.05) from the depth of 30 μm (44.410.5). It can be concluded that microhardness of the medium third of radicular dentine increased after the application of the 980 nm diode laser as measurements were far from the canal lumen, regardless of the irrigating solution used in biomechanical preparation.

ASSUNTO(S)

laser - odontologia hardness dentistry odontologia endodontia endodontics endodontia laser dentistry dureza - odontologia dentistry

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