CHARGES EXTRACTED FROM DENTAL CERAMICS - AN INDICATION OF PIEZOELECTRIC ACTIVITY

A method was established for demonstrating charge generation on the su rfaces of dental materials by means of mechanical loading with differe nt forces. With this experimental set-up charges could be extracted bo th from the surfaces that were mechanically loaded and from the surfac es perpendicular to the applied force. When specimens of certain ceram ics were subjected to mechanical loading and the charges extracted wer e related to the applied force, charges of up to 3 . 10-3 pC/N were re corded from the surfaces perpendicular to the applied force and charge s of up to 8 . 10(-3) pC/N from the surfaces that were mechanically lo aded. The results from this study indicate support for the hypothesis that the extracted charges were created by direct piezoelectricity. Ho wever, further studies are necessary for decisive proof that true piez oelectricity occurs in these materials.