Histopathological changes occur very rapidly in the pulp when the high-speed drill, which cuts into the dentin, is used. In this investigation, we wanted to confirm possible changes occurring in the histology of healthy, vital pulp within the first thirty post-operative minutes. Six premolars extracted for orthodontic reasons in adolescents between 12 and 17 years of age were evaluated. The teeth were removed and serial sections of the specimen, using classical histological procedures, were made. The histological evaluation under the light microscope revealed changes in the pulp, characteristic for acute inflammatory reaction, that is, hyperemia, extravasation of blood cells and aspiration of the odontoblast in dentin tubulus. We concluded that the turbine drill should be used only on the enamel of the tooth. We recommend using the low speed drill with maximal cold water for work on the dentin. Exposed odontoblastic processus and tubulus should be protected immediately after the preparation of the cavity.

Kod preparacija visoko-turažnim bušilicama, koje sežu u dentin, vrlo brzo nastupaju pato-histološke promjene u pulpi. Ovim radom smo htjeli utvrditi moguće promjene u histološkoj slici zdrave, vitalne pulpe, već unutar prvih trideset minuta post-operativno. Koristili smo šest premolara određenih za ekstrakciju iz ortodonskih razloga, adolescenata u dobi od 12 do 17 godina. Zubi su ekstrahirani i načinjeni serijski rezovi preparata, klasičnim histološkim metodama. Histološkom evaluacijom, pod svijetlosnim mikroskopom, smo pronašli promjene u pulpi karakteristične za akutnu upalnu reakciju, tj. hiperemiju, ekstravazaciju krvnih stanica i aspiraciju odontoblasta u dentinske tubuluse. Zaključili smo da u kliničkoj praksi treba turbinsku bušilicu koristiti samo za rad u caklini. Ostale zahvate u dentinu, preporučujemo raditi nisko-turažnim bušilicama uz maksimalno hlađenje vodom. Eksponirane odontoblastičke nastavke i tubuluse potrebno je odmah nakon preparacije zaštititi.