In vitro comparison of root surface roughness and bacterial adhesion following treatment with three different instruments

Abstract

Background: A novel device, piezoelectric 11 Gracey curet tip, reportedly combines benefits of a piezoelectric device and manual curet. The primary objective of this study was to compare root surface roughness outcomes between traditional manual curets and piezoelectric devices, as compared with this novel device. The secondary aim was to assess the level of adhesion of Streptococcus mutans on the root surface after instrumentation.

Methods: The groups consisted of the following: 1) Gracey curet; 2) piezoelectric scaler; 3) piezoelectric 11 Gracey curet tip; and 4) untreated control. Root specimens were obtained from extracted human teeth and randomly assigned to each group. Surface roughness measurements (Ra and Rz) were taken with a profilometer before and after instrumentation. After instrumentation, root specimens were inoculated with S. mutans and biofilm was dislodged. Various dilutions of resuspended biofilm were incubated on blood agar plates and colony forming units (CFU) values were measured.

Results: The experimental device resulted in significantly lower Ra and Rz compared with other groups (P < 0.01), and the Gracey curet was significantly lower than the piezoelectric tip and untreated control (P < 0.05). The Gracey curet and experimental device tip had significantly lower CFU values compared with the control (P < 0.05). There were no significant CFU value differences between the Gracey curet and both the piezoelectric and experimental device tips. There were no significant CFU differences between piezoelectric tip and both experimental device and control. There was no correlation between Ra and CFU values for Gracey curet, piezoelectric tip, or the control. However, correlation between Ra values and CFU approached significance for the experimental device (correlation = 0.66, P = 0.05).

Conclusions: Piezoelectric 11 Gracey curet tip is effective at resulting in a significantly smoother surface compared with traditional piezoelectric and hand instruments. CFU values with piezoelectric 11 Gracey curet tip were significantly lower than non-instrumented surfaces, but there were no significant differences compared with conventional methods.

Keywords: Streptococcus mutans; bacterial adhesion; periodontitis; surface properties.