Study of variations of the Bolton index in the Moroccan population depending on angle malocclusion class.

Many difficulties may arise during the finishing phase of orthodontic treatment on account of discrepancy between mandibular and maxillary tooth size. In 1958, Bolton devised the index that bears his name and enables possible tooth-size discrepancy to be diagnosed. Use of this index in practice has shown that it can vary depending on the different angle malocclusion classes. The aim of this work is to study variations of the Bolton index as a function of the malocclusion class in the Moroccan population, and to compare the results obtained with those of other populations. Ninety models were therefore selected in different groups of dental Class I, Class II and Class III malocclusions. The mesiodistal (MD) diameters of 12 maxillary and mandibular teeth were measured and the anterior and general Bolton indices were calculated. The results obtained show that there is no significant difference between the various groups of angle malocclusion classes, and that some other populations present results similar to those of the Moroccan sample.