Interoperator variability during polishing.
OBJECTIVE
The object of this study was to establish the 3 variables used in polishing by measuring the range of loads, speeds, and times used by practitioners when finishing and polishing samples of amalgam, resin composite, and glass-ionomer cement. These parameters could then be used to establish clinically relevant values that might optimize clinical finishing techniques.


METHODS
Samples of the 3 materials were attached to the load cell of a universal testing machine that was attached to an X-Y plotter. Practitioners were asked to finish the samples using 4 grades of a polishing disk system. Prior to using each grade of disk, the practitioner selected a speed. The sample was finished using one grade of disk until the practitioner was satisfied with the finish achieved. The process was then repeated with the next grade of disk. From the tracings for each disk the load and time were calculated.


RESULTS
There was a wide variation in the loads, speeds, and times used by the practitioners to finish the 3 materials, and it was not possible to find any relationship among the 3 variables. It appeared that practitioners finished the materials in an arbitrary manner.


CONCLUSIONS
No clear evidence was obtained to determine optimal combinations of load, speed, and time for finishing of amalgam, resin composite, or glass-ionomer cement. However, the results of this study indicate a range of values commonly used for each parameter in clinical practice, which could be useful for manufacturers in providing finishing instructions for their products.
Queen Mary University of London, England. cjonesstheaker@ntlworld.com
Colin S
CS
Jones
Richard W
RW
Billington
Gavin J
GJ
Pearson
D000180:Acrylic Resins; D003188:Composite Resins; D003723:Dental Amalgam; D003775:Dental Polishing / Q000379:methods*; D003793:Dental Restoration, Permanent / Q000379:methods*; D005899:Glass Ionomer Cements; D006801:Humans; D011140:Polyurethanes; D013997:Time Factors; D016474:Weight-Bearing
D000180:Acrylic Resins; C029012:Composite Dental Resin; D003188:Composite Resins; D005899:Glass Ionomer Cements; D011140:Polyurethanes; D003723:Dental Amalgam