Definition, epidemiology and etiology of Class III malocclusions [Definizione, epidemiologia ed eziologia delle III classi]

Objectives. To analyze international literature regarding Class III malocclusions. Materials and Methods. The different definitions of Class III malocclusion have been analyzed. Since the 18th century this malocclusion has long been viewed as one of the most severe facial deformity. Many Authors tried to find the right definition starting from Angle who described it as an "abnormal relation of the jaws, all the lower teeth occluding mesial to normal the width of one bicuspid" to Proffit who described this malocclusion as a deviation in the sagittal relationship between upper and lower jaw. Results. The incidence of Class III malocclusion in the white population has been reported to be from 2% to 3%. In the black populations it ranges from 4% to 6%, and in Asian population t comes up to 20-30%. Conclusions. Substantial evidence supports the theory of familial influence in mandibular prognathism and Class III malocclusion; however the etiology of Class III malocclusion is multifactorial because of an interaction of both hereditary and environmental factors.