Effect of Two Kinds of Er:YAG Laser Systems on Root Surface in Comparison to Ultrasonic Scaling: An in Vitro Study

Objective: To evaluate the capacity of Er:YAG laser application to eliminate calculus from periodontally affected root surfaces compared with ultrasonic scaling (US), as well as the possible root damage incurred from both types of instrumentation. Background Data: The benefits of the use of the Er:YAG laser as a coadjuvant to conventional periodontal therapy have not yet been determined. Materials and Methods: Forty human molars extracted due to advanced periodontal disease were used. A piezoelectric ultrasonic scaling (US) (Piezon Master (R) EMS) at 28,500 Hz was performed in the right area of the root. Two kinds of Er:YAG lasers, KaVo Key II Laser (R) at 120-140 mJ and KaVo Key III Plus Laser (R) equipped with a fluorescence-controlled feedback system applied at 160mJ with and without fluorescence feedback control, were used in the left area. The amount of residual calculus and the number and diameter of exposed dentinal tubules were calculated by scanning electron microscopy (SEM). Results: No differences were identified as to the amount of residual calculus between the four different laser treatments and US. The number of exposed dentinal tubules was higher as the output energies were increased for the laser treatments without feedback control, with a moderate increase in the mean diameter of the exposed dentinal tubules. Hardly any dentinal tubule exposure was observed as a result of treatment with feedback control. Conclusions: The capacity of the Er:YAG laser to remove calculus is comparable to US. Laser prototypes with feedback control allow a selective removal of calculus without any modification of the root surface.