THE PRESENT STATUS OF DENTAL ROTARY CUTTING PERFORMANCE TESTS

Appropriate methods of assessing the cutting ability of handpiece and rotary cutting instrument combinations are needed for research into th e processes involved in dental cutting. They are also required for the development of improved devices and recommendations on operation as w ell as for equipment specification and standards testing. In reviewing the literature on dental rotary cutting performance testing to evalua te available methods, the factors which may influence clinical cutting behaviour are identified as those related to characteristics of the o perator, handpiece, rotary cutting instrument, coolant/lubricant used and workpiece material. Existing industrial cutting theory is of limit ed help in understanding dental cutting in view of the differences bet ween the control of relevant variables in the two cases. Consideration is given to the ways in which the important variables have (or have n ot) been controlled in past studies of dental cutting and thus the cli nical relevance of available methods evaluated. Serious problems such as the lack of suitable test workpiece materials, as well as deficienc ies in current knowledge oi operator behaviour, handpiece characterist ics and effects of coolant/lubricant application are noted. It is conc luded that before improved, clinically relevant tests can be developed , further fundamental research in these areas is essential and that un til this is done, further work under arbitrary experimental conditions would be of little value.