| Figures/TablesFigures/Tables | ReferencesReferencesml version="1.0" encoding="UTF-8"?>
Statement of problem
As single-use rotary cutting instru
ments and electric handpieces beco
me
more available, the perfor
mance of these instru
ments with electric as co
mpared to turbine handpieces requires evaluation. In addition, if rotary cutting instru
ments
marketed as single-use instru
ments are used for
multiple patients, the effects on their perfor
mance of cleaning, sterilization, and repeated use are of interest to the clinician.
Purpose
The purpose of the study was to evaluate how the cleaning, autoclaving, and repeated use of single-use and multiuse rotary cutting instruments, with either a turbine or electric handpiece, affected their performance.
Material and methods
The effects on cutting performance of 2 handpieces (turbine and electric), 2 cleaning and sterilization conditions (cleaned and autoclaved versus noncleaned and nonautoclaved), and 6 different diamond rotary cutting instruments (4聽single-use and 2 multiuse) during simulated tooth preparations were evaluated by using a 24-treatment condition full-factorial experimental design. A computer-controlled dedicated testing apparatus was used to simulate the cutting procedures, and machinable glass ceramic blocks were used as the cutting substrate for tangential cuts. In addition, for each treatment condition, 8聽consecutive cuts, for a total of 192 cuts, were measured to assess the durability of the rotary cutting instruments. A linear mixed model was used to study the effect of instrument type, handpiece, cleaning, and sterilization, as well as the status and number of cuts on the outcome variables. The Tukey honestly significant difference test was used for the post hoc pairwise comparisons (伪=.05).
Results
Performance, as measured by the rate of advancement, decreased with the repeated use of rotary cutting instruments (m>Pm><.001), while cleaning and sterilization procedures improved the average performance of the 8 cuts (m>Pm>=.002). The electric handpiece showed a greater load than the turbine (m>Pm><.001) and a lower rate/load metric, but no differences in the rate of advancement. Significant differences were also detected among the different rotary cutting instruments tested with the Two Striper, which showed the highest cumulative performance of all groups.
Conclusions
The repeated use of both single-use and multiuse rotary cutting instruments decreased cutting performance. The use of a cleaning and sterilization procedure between cuts improved the average cutting performance. During a tangential cutting process, although the ease of advancement (rate/load) was greater for the turbine, the electric handpiece did not produce a statistically different cutting rate.