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

Aim of the study

To evaluate the possible antimicrobial effects of ultrasonic and sonic instruments on Gram + and Gram - periodontal pathogens.

Materials and methods

Suspensions of Actinobacillus actyno-micetemcomitans (Aa), Porphyromonas gingivalis (Pg), Campylobacter rectus (Cr) or Peptostreptoccus micros (Pm) were prepared and subjected to the action of ultrasonic and sonic instrumentation for between 30 and 150 seconds in vitro. After sonication the samples were diluted, cultured and incubated for 2 to 5 days at 37 °C.

Results

There was no significant reduction in the viability of the pathogenic bacteria tested in this study. It seems that the viabilities of Aa and Pg were only slightly affected by short periods (30 seconds) of exposure to sonication and other species were destroyed only after longer periods (150 seconds).

Conclusion

The use of sonic and ultrasonic instruments does not cause the destruction of the principle periodontal pathogens. This is contrary to earlier reports, which would lead us to believe other-wise.

Commentary

It seems that the main effect of sonic and/or ultrasonic instruments is the mechanical elimination of plaque. The reduction in the viability of bacteria would be dependent upon the frequencies and energy levels of the sonic/ultra-sonic instrumentation used.