The tooth wear index: a flawed epidemiological tool in an ageing population group.

With a greater number of people living longer and tending to retain many natural teeth, the problems associated with tooth wear are likely to place greater demands upon dental professionals in the future. Several attempts have been made to develop an index to measure tooth wear, for use at both the individual and population level. A review of these indices is undertaken, and difficulties experienced with the tooth wear index (TWI) of Smith & Knight (1984) in a large adult dental health survey is discussed. In the elderly population the scoring criteria of the TWI proved to be difficult to apply without additional qualification, and in cases of extreme wear a five-point ordinal scale was found to be inadequate to describe the range of wear observed. The concept of "pathological" levels of wear proposed by the TWI are challenged and modification to the index suggested for use among the elderly population.