Determining the limits of orthodontic treatment of overbite, overjet, and transverse discrepancy: a pilot study.

INTRODUCTION: Because of the severity of some malocclusions, it is not always possible to treat them without a combination of orthodontics and orthognathic surgery. However, many insurance carriers have difficulty in deciding whether such treatment should be covered. The purpose of this study was to develop a simple method that can be used by insurance carriers to determine when a malocclusion is not correctable by orthodontics alone.

METHODS: Twenty-eight orthodontists independently evaluated 30 sets of pretreatment dental models (10 with overjet from -6 to 12 mm, 10 with overbite from 60% to 100%, and 10 with transverse discrepancies from single tooth to total arch crossbite) to determine whether the conditions were orthodontically treatable. They were instructed to assume that growth was complete and that the treatment would not seriously compromise facial esthetics.

RESULTS: It was the opinion of the orthodontists that a positive overjet greater than 8 mm, a negative overjet of -4 mm or greater, and a transverse discrepancy greater than 3 mm were not orthodontically treatable. However, most orthodontists believed that they could treat all overbite patients without surgery.

CONCLUSIONS: These data can serve as a simple guideline for helping insurance carriers determine the need for orthognathic surgery.