In vitro evaluation of Er : YAG laser scaling of subgingival calculus in comparison with ultrasonic scaling

The purpose of the present study was to evaluate the effectiveness of Er:YA G laser scaling and the morphological and histological changes of the laser -scaled root surface in comparison with the effectiveness and root surface changes produced by conventional ultrasonic scaling. Fifty-three periodonta lly involved human extracted teeth with a band of subgingival calculus were used. The teeth were divided randomly into 2 groups for laser scaling and ultrasonic scaling. Laser irradiation was performed at an energy output of 40 mJ/pulse and 10 pulses/s under water spray, with the probe lip contacted obliquely to the root surface. Ultrasonic scaling was performed at a clini cally standard power setting. The time required for scaling, the scaled are a and the temperature changes were determined using both methods of treatme nt. The features of the scaled surfaces were examined by histological and s canning electron microscope (s.e.m.) observations. The Er:YAG laser provide d subgingival calculus removal on a level equivalent to that provided by th e ultrasonic scaler, without major thermal elevation. Macroscopically, the laser-treated root surface was somewhat rougher than or similar to the ultr asonically scaled root. However, the efficiency of the laser scaling was lo wer than that of the ultrasonic scaling. In addition, histological examinat ion revealed a thin deeply stained zone on the lased root surface. and s.e. m. analysis revealed a characteristic microroughness on the lased surface. The laser scaling provided a level of calculus removal that was similar to that provided by the ultrasonic scaling. However, the Er:YAG laser produced superficial. structural and thermal microchanges on the root cementum.