Curettes, ultrasonics and laser: in vitro changes in root roughness

Objectives:: Compare roughness and histology of root surface, after scaling with curettes, ultrasonics and Erbium:YAG laser (Er:YAG).

Methods: 21 teeth, extracted for periodontal reasons, with subgingival calculus, were divided in 3 groups(n=7) according to instrumentation: group A - Gracey curette ( Hu-Friedy®); group B - ultrasonics ( Piezon Master 400 - EMS®); group C - Er:YAG laser (Key III -KaVo®). 7 teeth (group D), extracted due to orthodontic reasons, had no instrumentation. Using laser profilometry, average roughness (Ra) and three-dimensional roughness (Rz) were calculated and statistically analysed (ANOVA, Tukeyxs, p<0,05). After obtaining undecalcified ground sections, root surfaces were stained with blue toluidine and histologically analysed with a magnification of x4.

Results: In profilometry analysis curette produced the smoothest surface (Ra=2,98µm; Rz=18,74µm) followed by ultrasonics (Ra=4,87µm; Rz=29,37µm) and by laser (Ra=6,80µm; Rz=36,19µm).There were no significant differences between the control (Ra=4,41µm;Rz=28,4 µm) and other groups. Only laser had a significantly (p<0, 05) higher roughness, comparing to curette.

Histologically the 3 instruments produced cement alterations. When compared to untreated areas, curette and ultrasonics removed a variable layer of cement and laser also produced some deep cement defects.

Conclusions: Curette had the lowest roughness values (Ra and Rz), comparing to ultrasonics and laser. Nevertheless, none of the forms of instrumentation was statistically different from the control. Laser produced the roughest surface, significantly different from curette. Histologically, laser produced considerable alterations on cement topography.