Mikrohärte der Kavitätenwände nach Fluoreszenz-unterstützter Kariesexkavation (FACE) in vitro

Even today, it remains a difficult task to differ between healthy and infected hard tooth tissue during caries therapy. The purpose of this study was to test the reliability of one of the many methods of caries diagnosis: the fluorescence of hard tooth tissue. Thus, it was the aim of the study to evaluate the conventional method of caries therapy to the fluorescence-supported treatment of infected hard tooth tissue. A total number of 44 carious human teeth were tested for their microhardness of dentine after caries excavation. Therefore the teeth were subdivided into randomized groups of which one half was treated conventionally while the treatment of the other half was supported by induced fluorescence. The caries of every single tooth was excavated under standardized circumstances: The terminal point of excavation in the conventional group was defined by testing the quality of the dentine with a dental probe. In the fluorescence-supported group the teeth were treated until there was no red, for infected dentine typical, fluorescence noticeable any more. Subsequently the teeth were cut in half through the middle of the cavity and placed onto an object plate so that the microhardness of the dentine could be evaluated. Every series of measurement started at the margin of the cavity and continued over a total distance of 630μm, at intervals of 120 μm, into the dentine. The results showed a significant difference between the conventional and the lasersupported group. In the outer margin of the cavity, the dentine of the lasergroup teeth was noticeably weaker than the one from the conventional-group whilst the difference got smaller the further the test series proceeded into the circumference of the cavity. It has to be assumed, based on the evidence of this study, that the support of fluorescence during caries therapy can prevent an excavation of intact hard tooth tissue. However, in the case of a very profound cavity, it is not recommended to abstain from the usage of a dental probe since the dentine close to the dental pulp can emit fluorescence itself when exposed. In addition, the fluorescence-supported caries treatment showed, compared to the conventional group, a distinct time saving in vitro, which still has to be affirmed in clinical practice.