CUTTING EFFICIENCY OF A MIDINFRARED LASER ON HUMAN ENAMEL

In this study, the cutting ability of a newly developed dental laser w as compared with a dental high-speed handpiece and rotary bur for remo val of enamel. Measurements of the volume of tissue removed, energy em itted, and time of exposure were used to quantify the ablation rate (r ate of tissue removal) for each test group and compared. Cutting effic iency (mm(3)/s) of the laser was calculated based on the mean volume o f tissue removed per pulse (mm(3)/pulse) and unit energy expended (mm( 3)/J) over the range of applied powers (2, 4, 6, and 8 W). The specime ns were then examined by light microscopy and scanning electron microg raphs for qualitative analysis of the amount of remaining debris and t he presence of the smear layer on the prepared enamel surface, Calcula tions of the cutting efficiency of the laser over the range of powers tested revealed a linear relationship with the level of applied power. The maximum average rate of tissue removal by the laser was 0.256 mm( 3)/s at 8 W, compared with 0.945 mm(3)/s by the dental handpiece. Ligh t microscopy and scanning electron micrograph examinations revealed a reduction in the amount of remaining debris and smear layer in the las er-prepared enamel surfaces, compared with the conventional method. Ba sed on the results of this study, the cutting efficiency of the high-s peed handpiece and dental bur was 3.7 times greater than the laser ove r the range of powers tested, but the laser appeared to create a clean er enamel surface with minimal thermal damage, Further modifications o f the laser system are suggested for improvement of laser cutting effi ciency.