Some Effects of Developmental Changes on the Indices of Malocclusion

The assessment of the prevalence of disease has been accepted as an integral part of the activities of public health. In order to assess such prevalence, tools for measuring the degree as well as the absence or presence become essential. One of the most common tools employed has been the disease-index. In dental public health, the absolute prevalence of malocclusion still remains unknown. Many investigators’. ? * ?, +, ? have attempted, however, to describe the prevalence of malocclusion by the use of various methods of measurement (indices). When the scores from these indices have been plotted against time, that is, against the ages of the group of individuals under investigation, fluctuations usually were observed. One of these indices has been selected as an example to demonstrate the fluctuations. This index contained measurements that had been utilized in other indices of malocclusion and it also seemed to be the most popular, yet the most misused, index of malocclusion. It was proposed by Drakerl in 1958, and was called the Handicapping Labio-lingual Deviations (HLD Index). When the HLD Index first was described, a definite distinction was made between the concepts of malocclusion and orthodontic handicap. As Draker stated, a malocclusion implies a diagnosis, a process achieved by consideration of the etiology and a differential diagnosis. An orthodontic handicap was defined from a statement developed at the White House Conference on Child Health and ProtectionG: “A sound principle would seem to be to try to establish empirically the point, with respect to each trait under consideration, at which some definite handicap or dysfunction begins to be associated with extreme variation.” “An extreme deviation from the ‘norm’ is, therefore, considered a handicap,” continued Draker. Summarizing, he stated that “labio-lingual deviations from a fictitious norm rather than the state of occlusion are of epidemiological importance in establishing prevalence for physically handicapping orthodontic defects, and the degree of the physical handicap.” Draker, then, concluded that the HLD Index could be used to measure, not only the point where extreme variation began as an orthodontic handicap, but also to measure the degree of such handicap. Even though Draker stated that the HLD Index could not measure malocclusion, the measurement of malocclusion by the HLD Index apparently was implied by 8, 9 x lo