Lack of antimicrobial effect on periodontopathic bacteria by ultrasonic and sonic scalers in vitro

Background: The purpose of this study was to assess the antimicrobial effects of a sonic and ultrasonic scaler generally used for subgingival scaling on gramnegative and gram-positive periodontopathic bacteria. Method: Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Campylobacter rectus, or Peptostreptococcus micros were suspended in Schaedler's broth medium and treated by a sonic or a magnetostrictive ultrasonic scaler for 30 a and 150 s in vitro. Bacterial suspensions treated by an ultrasonic cell disruptor served as a positive control and untreated bacterial suspensions served as a negative control. Following sonication, samples were serially diluted, streaked on blood agar plates and incubated for 2-5 days at 37 degrees C. Results: Treatment by the sonic or ultrasonic scaler for up to 150 s did not reduce the viability of any of the tested periodontal pathogens. Compared to untreated controls, the viability of A. actinomycetemcomitans and P. gingivalis was significantly (p<0.05) reduced only following ultrasonication with the cell disrupter after 30 s (0.72 and 0.54 log CFU/ml, respectively) and of A. actinomycetemcomitans P. gingivalis, C. rectus and P. micros after 150 s (1.98, 1.34, 1.95 and 1.98 log CFU/ml, respectively). Conclusion: The data of the study may indicate that the assessed sonic and ultrasonic scaler used for subgingival debridement do not result in killing of the tested periodontal pathogens.