Purpose: To assess the effectiveness and side effects of three sonoabrasive systems and conventional rotary cavity preparation.
Materials and methods: Standardized artificial carious lesions were placed in 48 human premolars at mesial and distal surfaces. Three dentists prepared eight cavities each using (1) diamond burs, (2) Sonicflex 2000 L/N (HS), (3) an experimental air scaler (HS.EXP), and (4) the Piezon Cavity System (PCS). A small hemispherical preparation tip (Sonicsys micro) was utilized with the airscalers in Groups 2 and 3. Loss of substance was determined by weighing. Residual caries and damage to the adjacent tooth were assessed by two calibrated investigators. Each cavity was digitally photographed prior to planimetrical measuring of its circumferential dimension. Quality of the cavities' margins was examined by SEM.
Results: Rotary preparation required less time (4 minutes 53 seconds) than oscillating preparation with HS (6 minutes 45 seconds) or PCS (7 minutes 45 seconds), (Scheffé, P< 0.05). Preparation with HS.EXP (5 minutes 52 seconds) was not different from rotary and HS. 64% of all cavities were completely excavated, 28% showed distinct and 8% marked residual caries. However, chi2-tests did not reveal differences in caries removal between the systems. Oscillating preparation with HS as well as the experimental air scaler in combination with the hemisphere resulted in less trauma to adjacent tooth surfaces than rotary preparation and the PCS system, (chi2-tests P< 0.05). HS.EXP caused less loss of substance (Scheffé, P< 0.05). Regarding circumferential extension of the cavities, there were no differences between the groups.