Kariesprävention durch Irradiation mit einem CO(2)-Laser bei einer Wellenlänge von 10,6 µm : ein In-vivo-Versuch

摘要

In the present study the caries preventive mechanisms of a CO2 Laser (λ: 10.6 µm) were evaluated in-vivo for the first time. The ideal parameters for CO2-laser-irradiation have been successfully tested before in vitro and showed a strong and significant effect on the resistance of dental enamel against carious demineralisation with a maximum caries reduction of 81 %. In order to establish the caries model, a test model was established. Thereafter the main study consisted of 48 female rats type sprague dawley. The rats were divided into 4 groups: A laser group (GL), a fluoride-group (GF), a laser and fluoride-group (GLF) and a control-group (GC). All animals received a cariogenic diet, which contained mainly sucrose together with a 10% sucrose-water-solution. Both were fed until the end of the study and were available ad libitum. Furthermore, before the start of the experiment, all rats were treated with chlorhexidine and antibiotics to reduce the bacterial count in their oral cavity. Afterwards, on three consecutive days the animals were inoculated with s.mutans in order to establish distinct caries activity. On day 7 of the trial, the molars of the rats from GL and GLF were irradiated with the CO2-Laser (λ: 10.6 µm). The molars of GF and GLF underwent a two-time application of Duraphat varnish. At the end of the trial the rats of all 4 groups were terminated and jaws were extracted for evaluation. The analysis included measurement of buccal plaque accumulation, the evaluation of smooth surface caries as well as the presence of fissure caries. For this matter the method established by Keyes (1958) was used, whereas carious lesions were classified by their extent and depth into E, Ds, Dm and Dx. The results demonstrate reduced presence of buccal plaque and smooth surface lesions. With reference to fissure caries, there was a significant difference between the control group and all other groups. The results clearly indicate, that irradiation with a CO2-laser is an effective method for decreasing caries in dental enamel in the rat compared to the control group (p = 0,073). However, the impact is not significantly lower (p = 0.0001) than the twofold application of the fluoride varnish (NaF 5 %). In light of the fact that it wasn’t possible to reproduce the optimal parameters for laser irradiation in the oral cavity of the rat, it would be necessary to re-examine the outcomes of the present study in another in vivo or in situ experiment, before the caries-preventive effects of CO2-Lasers can be clinically applied to humans