The purpose of the present study was to evaluate pulpal blood flow rate during Nd: YAG laser irradiation to yingxiang. Twelve volunteers at Tsurumi University School of Dental Medicine participated in this study. An Nd: YAG laser was irradiated to the left yingxiang for 30 sec at 100 mJ 15 pulses/sec (1.5W). Maxilla right canine pulpal blood flow rate was measured by a laser Doppler flowmeter during the irradiation, and the oxygen saturation was monitored throughout the irra diation. In all subjects, the pulpal blood flow rate increased statistically significantly during laser irradiation (p < 0.01), but the oxygen saturation was not affected. The maxilla right canine pulpal blood flow rate increased immediately after Nd: YAG laser irradiation to yingxiang. The results suggested that the pulpal blood flow rate was influenced immediately after the Nd: YAG laser was irradiated to the acupuncture point.
The aim of this study was to clarify the effects and problems of the program of experimental practice of carbon-dioxide laser for fourth grade dental students. We have been adding laser irradiation practice to the current practice of opera tive dentistry for fourth-year students since 2005. The students were divided into nine groups and asked to fill out a pre-prac tice questionnaire. Each group then received basic lectures on the principle of the carbon dioxide laser, and were shown how to handle the laser instruments prior to the laser irradiation practice. Each student irradiated the carbon dioxide laser to white meat, and then completed a post-practice questionnaire. Comparison of the results of the pre-practice and post-practicae questionnaires showed the following: Regardless of the knowledge of biological mechanism or healing of laser irradiation, al most all students took some interest in the laser, but the lecture and laser irradiation practice apparently stimulated students'curiosity and gave them an incentive to study the laser mechanism of the carbon-dioxide laser. These results suggest that laser practice carried out before clinical practice stimulated their motivation and was educationally effective.
Laser therapy is currently applied in various dental fields. Lasers are used not only in oral surgery such as soft tissue incision and coagulation, but also for periodontal therapy, pulp treatment including pulpectomy and infected root canal treatment, tooth preparation, dental caries prevention, and pain relief and acceleration of wound healing for stomatitis, dentin hypersensitivity, and temporomandibular disorder. The laser systems used in dental treatment are mainly divided into two types based on the characteristics of the wavelength: the surface absorption type and the tissue penetration type. The absorption characteristics vary depending on the laser wavelength, and the influence of laser irradiation on body tissues is especially dependent on absorption by water, which accounts for approximately 70% of the body. The Er: YAG and carbon dioxide (CO2) lasers have particularly high water absorption characteristics, and almost all the laser energy is absorbed in the most superfi cial tissue layer and the irradiation does not penetrate into deep tissues. In contrast, lasers with a wavelength in the visible to near-infrared range reach deep tissues, since this energy is unlikely to be absorbed by water. Therefore, Er: YAG and CO2 lasers are superior in terms of vaporization efficiency, whereas visible to near-infrared lasers have stronger coagulation effects. Power density and oscillation mode are also key factors that determine laser characteristics, and the clinical effects of lasers are characterized by a combination of these factors and wavelength.
Dental lasers are now commonly used in Japan. Caries treatment by laser is reimbursed by national medical insurance and many small clinics use them in their daily practice. However, dental school students do not receive adequate training on the use of lasers and so need individual training after they start their practice. “Safety Control in Laser Dentistry” is a course held by the training committee (chaired by Dr. Tsuyoshi Shinoki) of the Japanese Society for Laser Dentistry. It is the first dental laser safety course conducted by the committee. It is attended by not only dentists, but also dental hygienists and other dental staff, and the course covers safety procedures necessary in daily clinical practice, so the course subtitle is“Laser treatment and staff's roles”. The topics in this course include the characteristics of laser light and the risks, the safety classes of lasers, protection goggles, accidents and adverse effects in laser dentistry, preoperative safety measures, test irradiation, safety measures for treatment, postoperative safety measures, and infection countermeasures in daily practice. The responsibility of safety control comes when a dental laser is purchased. It is strongly recommended to read the laser's instruction manual. Safety control is intended to make sure that you take necessary precautions every day. Sufficient safety procedures lead to successful application of lasers. This course is designed to improve the safety of laser dentistry for attendees.