In Vitro Studies on Laser Scaling of Subgingival Calculus With an Erbium:YAG Laser

Abstract

The effectiveness of a newly‐developed Er:YAG laser with a fiber delivery system to remove subgingival calculus was examined in vitro. Fifty‐three (53) periodontallyinvolved human extracted teeth with a band of subgingival calculus were used. Two experiments were conducted: in experiment 1, laser scaling was performed with water irrigation on a straight line and on a broad area, against the subgingival calculus at the energy levels of 10 to 120 mJ/pulse (3.5 to 42.4 J/cm2/pulse) and the pulse repetition rate of 10 pps. The morphological changes of the laser‐scaled site were observed by SEM, and the efficiency of laser scaling was determined. In experiment 2, laser scaling was performed with and without water irrigation at 30 mJ/pulse and 10 pps. The morphological changes, the efficiencies, and temperature changes with and without water irrigation were compared. The pulsed Er:YAG laser used with water irrigation was able to remove the subgingival calculus from the tooth root effectively at the energy level of about 30 mJ/pulse (energy density: 10.6 J/cm2/pulse) and 10 pps, under in vitro conditions. Ablation of the tooth substance on laser scaling was generally observed within the cementum. There was little increase in temperature on the root surface during laser scaling. This study suggests the potential for the clinical application of the Er:YAG laser in subgingival scaling. J Periodontol 1994; 65:1097–1106.

Analysis of Er:YAG Lased Dentin Using Attenuated Total Reflectance Fourier Transform Infrared and X-ray Diffraction Techniques

“…As a result, dentin temperature might have been raised higher than 60 a temperature at which collagen transforms from highly ordered helices to amorphous gelatin 26) . Previous research work 27) showed that using of Er:YAG laser with parameters of 30 mJ/pulse and 10 pps the root temperature increased under dry condition to 66.5 , while that under wet condition remained at 28.6 . Moreover, it was reported that the calcified collagen molecules in dentin might break down at approximately 175 , however changes in collagen structure, which might occur with such heating and dehydration, can be reverted to natural conformation after rehydration provided that the surface temperature did not increase beyond 175 28) .…”

XPS analysis of the dentin irradiated by Er:YAG laser

“…The denatured dentin irradiated by an Er:YAG laser beam has a similar structure to that of dentin heattreated at 500°C and 800°C and analyzed by XRD analysis 20) . The root temperature was elevated to 66.5°C when subjected to Er:YAG laser irradiation with a pulse energy of 30 mJ at a repetition rate of 10 Hz under dry conditions, while under wet conditions it was elevated to 28.6°C 33) . Changes in the components of dentin are not expected to occur at these temperatures.…”

Alternative Treatment Approaches in Chronic Periodontitis: Laser Applications

“…The ability of Er:YAG laser to remove subgingival dental calculus has already been shown in in vitro studies (Aoki et al, 1994;Folcwaczny et al,2000;Frentzen et al, 2002). In 1994 Aoki et al first documented the capacity of Er:YAG laser to remove dental calculus in an in vitro study, using a pulsed mode under irrigation.…”

“…The calculus was completely removed without thermal change of the root surface. Aoki et al (1994) evaluated the effectiveness of Er:YAG laser compared to conventional ultrasonic scaling. The panel set was 40 mJ/pulse (14.2 J/cm 2 per pulse) and 10 Hz with water spray using a conventional tip at 30° to the root surface.…”