| 摘要 |
Preparation of a tooth aims at sufficient removal of substance while saving the vitality of the pulp. In particular, opening of the pulp cavity is to be avoided. At present, there is no clinically usable method for measurement of the distance between the tooth surface and the pulp. The description of the invention presents apparatus that permit reliable determination of the residual dentine thickness left behind during preparation, by measurement of the electrical resistance of the dentine. Unintentional opening of the pulp cavity is avoided. It is possible to differentiate dentine areas with widely open dental canaliculi from sites with obliterated canaliculi. This solution to the problem is based on the finding that the resistance of dentine depends on its thickness and the width of the dental canaliculi and that the dentine conducts the current much better in the direction of the canaliculi than on a path deviating therefrom.
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