[The effect of ultrasonic condensation on gold condenser fillings and on the abutting dental hard tissue].
A prototype ultrasonic condensation device was applied to condense two class V mat-gold fillings in each of 10 extracted molars (group A). For 10 other molars a conventional electric device was used (group B). In five molars of each group the nib face of the condenser was not brought into direct contact with the cavity margins (AI/BI); in the other five molars of the sample this was done intentionally (AII/BII). Only one of the two fillings in each tooth was polished. Replicas of the fillings were examined for marginal adaptation by means of scanning electron microscopy (SEM). After dye penetration for 24 h, ground sections of the teeth were examined by light microscopy and SEM. Enamel cracks and cementum injuries were predominantly observed in unpolished fillings of group AII and BII. The marginal adaptation in group AI was significantly better than in group AII, BI, BII, respectively. The polished fillings demonstrated a significantly lower incidence of dye penetration than unpolished restorations. Our results indicate that only direct treatment of the cavity margins with the ultrasonic device causes enamel cracking and cementum injuries. Avoidance of direct treatment of the cavity margins seems to result in better marginal adaptation. In addition to that, polishing seems to lead to lower rates of microleakage.