[Surgical laser in dentistry in 1989]. / Le laser chirurgical en odontologie en 1989.

After many years of microscopie, cellular and molecular studies, the use of Laser rays progressively developed in dentistry. This therapeutical "tool" is now well established in numerous dental fields: cariology, pathology of oral mucosa, periodontics... The Europeans have great advance in this research area and current progress is the clear proof of their work efficiency.

Dental pulp exposed to the CO2 laser beam.

Traumatic inflammation due to application of CO2 laser beam on teeth (dentin and pulp) of Beagle dogs and Macaca Monkeys, stimulate in dentino-pulpal tissue morphological phenomena studied after 5 days, 1, and 3 months by microscopy and microradiography. After a dentin exposure to a density of energy from 2 X 10(3) J/cm2, the first cell layers of the pulp tissue show a rarefaction and a cellular degeneration, followed by a neoformation of calcified dentin, of about 300 microns thick in 3 months, due to the excitation of odontoblasts or produced by pulpal cells functioning before. A density of energy of 10(3) J/cm2 order applied to the pulp beads to its partial necrosis, to various inflammatory aspects and to a quasi-constant regeneration by a neo-dentin bridge of 200 microns at 1 month. The analysis of cell activity seems able to be investigated from this method.

[Experimental research on the preparation of dentin-pulp tissue of teeth exposed to CO2 laser beams in dogs and macaques (Macaca mulatta and Macaca fascicularis]. / Recherches expérimentales sur la réparation du tissu dentino-pulpaire des dents exposées au rayonnement du laser à CO2 chez le chien et le macaque (Macacus mulatta et Macacus fascicularis).

Traumatic inflammation due to application of CO2 laser radiation (lambda = 10.6 microns) on the dentin and on pulp of 342 teeth of 8 dogs (Beagle) and of 6 monkeys (Macaca sp. mulatta et fascicularis) stimulate in dentino-pulpal tissue morphological phenomenon, studied after 5 days, 1 and 3 months by microscopy and microradiography. The dentin exposed to a density of energy of: 2 X 10(3) J/cm2 shows a burn, a rarefaction and a cellular degeneration, followed by a neoformation of calcified dentin, of about 300 microns thick in 3 months, due to the excitation of odontoblasts or produced by pulpal cells functioning before. A density of energy of 10(3) J/cm2 order applied to the pulp beads to its partial necrosis, to various inflammatory aspects (vascular, cellular, tissular) and to a quasi-constant regeneration of by a neo-dentin bridge of 200 micron at 1 month. This method seems able to allow the analysis of cell activity (start, activation, blocking).

Treatment of dental decay by CO2 laser beam: preliminary results.

Results obtained from two clinical cases, representative of 1,140 human teeth treated by CO2 laser beam during 3 years, announce a new conception of treatment of dental caries. The beam (P = 4 - 5 W, energy density of 9 to 25 kw/cm2) causes a dentin healing which becomes sterile, chemically and physically more resistant than pathological dentin. In addition, this exposure leads to an activation of the dentinogenesis supported by X-ray, confirming histo-pathological results obtained from experiments performed on animals.

[Contribution of the CO2 laser in the sterilization of various infections of dental origin]. / Apport du laser à CO2 dans la stérilisation de certaines infections d'origine dentaire.

The CO2 laser (lambda congruent to 10.6 micrometers) induces structural changes in the mineralised tissues of the dental organ: fusion, recristallization, increase in hardness and sterilisation. (Report at the Academie des Sciences, December 1980). Thanks to Professor C. Freche, 200 cases have been treated using the FLF 25 since June 1980: 1) apical infections: 40 cases. The laser closes the lumen of the canaliculi, hardens and sterilises the dentine; 2) dentino-pulp infections: 150 cases. The laser volatilizes the area of caries in live teeth, hardens and sterilises the dentine. With exposed pulp (6 cases) the laser coagulates, sterilises and permits closure; 3) periradicular infections: 10 cases. The laser cleans, sterilises and hardens. Parodontal pockets are cleansed; 4) mucosal or gingival surgery is bloodless, atraumatic and particularly facilitated. The laser has become an instrument for the prevention of the complications of dental disease.

[Optic microscope observations on changes in enamel and dentin induced by laser beams]. / Observations en microscopie optique des modifications de l'émail et de la dentine induites par le rayonnement laser.

By a laser beam, enamel and dentin are changed into an identical crystalline structure observed in reflected light and described as recrystallisation after fusion. The Vickers pyramidal numbers of these areas are the same as the mature enamel surface (590 VPN). The theoretical calculation proved that after irradiation in enamel there is an elevation of temperature about 2,5 degrees C through 3 mm. These observations suggest that new operative techniques might be possible.