Ag. Gegauff et al., HANDPIECE DEGRADATION ASSOCIATED WITH PERFORMANCE TESTING OF DIAMOND ROTARY CUTTING INSTRUMENTS, Australian dental journal, 43(5), 1998, pp. 342-348
Reliable standardized testing of dental rotary cutting instruments rem
ains a problem because of the many significant parameters that require
identifying and quantifying. In a previous study, handpiece wear or d
egradation was identified as a potentially significant confounding var
iable leading to the suggestion that the use of industrial hand-pieces
might be necessary. Therefore, the objective of this investigation wa
s to measure and compare industrial and dental air rotor degradation d
uring a simulated diamond rotary cutting instrument test. Two dental a
nd two industrial products were tested in a random sequence using thre
e replicate samples of each air rotor. The simulated test consisted of
10 diamond instruments each making 90 passes through a float glass su
bstrate. The testing apparatus comprised a computer-interfaced device
that controlled the contact force between the cutting diamond and the
substrate. Air rotor performance was based on the time required to cut
a standardized path through the substrate. The performance change tha
t occurred from diamond instrument to instrument during the simulated
test was attributed to air rotor degradation. Multiple regression anal
yses showed significant differences between replicate samples of the s
ame type and between regression intercepts for different air rotor typ
es. Surprisingly, four air rotors exhibited improving performance duri
ng the simulated test. Changing air rotor performance must be consider
ed to achieve reliability for the testing of diamond rotary cutting in
struments.