[An experimental study of the effects of drilling with dental high speed turbine on culture cells (in vitro) (author's transl)].

A drilling at 500 000 R.P.M. with a dental high speed turbine was made either to a tissue culture bottle or to a test tube, in which mouse L fibroblasts were grown for 2 days with YLH medium supplemented with 10% bovine serum, in order to examine the effects of high speed drilling to the cells in vitro, Experiments were carried out with the following three conditions; (1) Drilling of outer surface of the glasswares at the inner surface on which the cells were attached, with a water coolant, (2) Drilling of the same place without a water coolant, and (3) Drilling of a remote area of the glasswares where no cells were grown. The last experimental condition permitted to give a sole effect of vibration accompanied with the drilling. Rates of cell multiplication and morphological observation were obtained on 2 days and 5 days after the glasswares were drilled. Rates of cell multiplication showed no change between the experimental conditions and control. This means that heat generation, vibration and/or their compound effects during drilling did not deter cells from growing. Morphological change of the cells due to the drilling was parallel to the results of cell multiplication except the drilling without a water coolant. When drilled without a water coolant, the cells around the drilled area was deteriorated and died after 24 hours. However, most of the cells away from the drilled area were not affected. The present results can not directly apply to the drilling in dental clinic, since in vivo condition has more complicated situation, some of which can not be simulated in in vitro environment. However, the in vitro results can surely be important information in resolving drilling effects in vivo.