Kenzo Kataoka

Novel laser contact probe for periodontal treatment

Application of the erbium: YAG laser to periodontal treatment has been attempted and preferable results have been reported for calculus removal, vaporization of granulation tissue, periodontal pocket sterilization and so on. However, it has been difficult to reach and treat some conditions involving complex root morphology and furcated rots with conventional probes. The new broom probe was designed and tested to overcome these obstacles. The probe was made of 20 super-fine optical fibers bound into a broom shape. The experiments were carried out to evaluate the destructive power of a single fiber and to examine the morphology of tissue destruction and the accessibility to a bifurcated root of a human tooth using the broom probe. The Er:YAG laser prototype was used. A flat specimen plate was made by cutting the root of a cow tooth and then attached to an electrically operated table and irradiated under various conditions. The specimens were examined with both an optical and scanning electron microscope. The irradiated surfaces were also examined with a roughness meter. An irradiation applied with a single fiber with an energy level of 1 to 1.5 mJ at its tip results in a destruction depth of 3 to 24 micrometers . The optimum conditions for the fibers of this probe was 1.0 mJ at 10 pps and a scanning speed of 100 mm/min. No part of the tooth surface remained un-irradiated after using the broom probe to cover the surface 5 times parallel to the tooth axis and then five times at a 30 degree angle to the previous irradiation at a power of 20 mJ at 10 pps. Also curved and irregular surface were destroyed to a maximum depth of 19 micrometers . In conclusion, these results suggest that the broom probe would be applicable for periodontal laser treatments even if the tooth surface has a complex and irregular shape.

The treatment of dental pit and fissure caries by an Er:YAG laser with an experimental tip

Abstract This is a report of newly developed experimental contact irradiation tip for an Er:YAG laser to remove dental pit and fissure caries. The purpose of this study was to examine the effectiveness of the experimental tip in the removal of dental pit and fissure caries and filling by the restoration with low viscous composite resin or compomer as a filling material. In experiment 1, we examined the removal effects of this tip and the characteristic properties using bovine extracted teeth. In experiment 2, we evaluated the sealing ability of the restorative filled cavity it prepared by laser using die penetration test. The cavity prepared with the laser was a narrow cone shape. There was no difference in the sealing ability of the filling material between cavities formed by the air turbine and the laser. It is suggested that the treatment of dental pit and fissure caries is possible with Er:YAG lasers using the experimental tip and low viscous filling materials.

Cavity preparation for metal inlay by experimental tip for Er:YAG laser

Abstract The dental Er:YAG laser which is mainly used for dental hard tissue cutting was recently developed. In restorative dentistry, this laser has usually been used in composite resin restoration, but not for cast metal inlay restoration. This is because it is difficult to make the cavity form, such as retention form and convenience form, by using laser irradiation. At the 6th ISLD meeting, we reported an experimental chisel-shaped contact tip (ECSC tip) for use in cavity preparation for cast metal inlays. In this study, we examine a newly developed, modified experimental tip in inlay cavity preparation using an Erwin (ML22:HOYA & MORITA). This tip is composed of an arrangement of seven optical fibers having 0.2 or 0.3 mm diameter in a single row. The tooth-cutting efficacy of this tip was examined using extracted human and bovine teeth, and the irradiated sites were observed with SEM. The cutting efficacy of the experimental tip for both enamel and dentin was better than that of the ECSC tip. However, the surface flatness after cutting using experimental tip was poorer than the of the ECSC tip. It is suggested that inlay cavity preparation is possible using Erwin with this tip.

Low-power irradiation of Er:YAG laser using broom-type probe for dentine hypersensitivity

This study was performed to examine the possibility of Er:YAG laser for dentine hypersensitivity treatment using a novel laser probe; broom type probe. The morphological change of dentinal tubules of bovine dentine plate after low power laser irradiation (5 or 10 mJ, 10 pps) or boiling was observed by SEM. Fifty teeth from 13 patients aged 31-54 years with complain of dentine hypersensitivity were treated by laser irradiation at 25-35 mJ, 10 pps using the broomed probe. Clinical effect of laser irradiation was verified by the examination of sensitivity rate to cold water, air blow and mechanical stimuli of explorer at before, immediately after, and 1,3,5 and 12 weeks after laser irradiation. The ratio of blockade and reduction of dentinal tubules after laser irradiation was 16-61%. The accumulation due to vaporization of water in dentinal tubules and degeneration or coagulation of organinc elements at the site of blockade and reduction were superficially described by SEM. Remarkable clinical improvement of dentine hypersensitivity by laser was admitted but relapse was also detected partially. The present study suggests low power irradiation of Er:YAG laser would be effective on dentine hypersensitivity, but a partial limitation of laser treatment for dentine hypersensitivity may be exited.