Evaluation of the effects of Er:YAG and Nd:YAG lasers and ultrasonic instrumentation on root surfaces

Abstract

Objective: Evaluate the effects of Er:YAG and Nd:YAG lasers on the morphology and chemical composition of root surfaces and compare them with those produced by using ultrasonic instrumentation (US).

Background data: The benefits of the use of Er:YAG and Nd:YAG lasers as an adjunct to conventional periodontal therapy have not yet been determined.

Materials and methods: The radicular surfaces of 18 extracted human multi-radicular teeth were treated for 1 min on the right side of the root either with laser (Er:YAG, 2940 nm, 10 Hz, output 80 mJ/pulse, 100 mJ/pulse, and 120 mJ/pulse, 250 mus pulse length, spot size 0.8 mm, or Nd:YAG; 1064 nm; 10 Hz; output 0.5, 1.0, and 1.5 W; 150 micros pulse length; spot size 0.6 mm) or on the left side of the root with US (28,500 Hz, medium power, and standard tip). Subsequently, the teeth were subjected to scanning electron microscopic (SEM) examination and energy dispersive x-ray (EDX) spectrometric analysis.

Results: SEM examination of the areas treated with US showed a smooth appearance. In all specimens from the experimental groups treated with Er:YAG laser, entire cementum layers were removed and dentinal tubules were exposed. EDX analysis of root surfaces treated by Er:YAG laser at 120 mJ/pulse showed an increase in the peak intensities of calcium and phosphorus more than that seen with US treatment. When Nd:YAG laser irradiation was utilized, SEM examination showed effects such as melting, and fissuring of the root surface. EDX analysis of root surfaces treated by the Nd:YAG laser at 1.5 W revealed some changes in the elemental composition, with the peak intensities of calcium and phosphorus decreased in relation to the levels obtained by US treatment.

Conclusions: US treatment better preserves the original morphology of cementum compared with Er:YAG and Nd:YAG laser treatment.