Erosion
Holst and Lange (1939) coined the term 'perimylolysis' to describe the distribution of erosion on the upper palatal surfaces secondary to vomiting, reflux and regurgitation.5 They cited a 1929 thesis by Fleury as the source for the term 'mylolysis' which alluded to the slow destruction of coronal tooth tissue. Neither term is useful since they are not specific descriptors for the distribution of intrinsic erosion: extrinsic erosion has a similar intra-oral presentation (fig. 2).6

The impact of eating disorders upon oral health was initially reported by Hellstrom (1977)7 and Hurst et al. (1977).8 Since then there have been dozens of case reports and reviews.9-12 The original publications found that the severity and distribution of dental erosion differed according to whether or not the subjects induced vomiting.7,8 In general, self-induced vomiting (SIV) resulted in an increased frequency of erosion on palatal surfaces but both research groups noted that the diet of their subjects included significant quantities of low pH beverages and fresh fruit. The latter was eaten to induce diarrhoea. A third of both the anorexics and bulimics sampled by Roberts and Li were reported to suffer with erosion despite the observation that only 65% of the anorexics vomited compared to all the bulimics.13 The strength of association between vomiting and erosive toothwear was not assessed until more recently. The frequency, duration and total number of vomiting episodes (frequency « duration) were not linearly associated with erosion14 and similarly no difference in the level of erosion was found between those who vomited more or less frequently.15 Both studies, however, reported an increased frequency of erosion in subjects with SIV and therefore some other factor(s) must be involved in determining whether or not erosion occurs.