Skeletal components and classification of Class III malocclusions [Analisi delle componenti strutturali e classificazione delle III classi]

Objectives. To provide a wide and updated analysis of the international literature regarding Class III malocclusions. Since their skeletal component can be very different, it is not possible to isolate a significant feature of their potential development. Methods. The Early studies suggested that the mandible was the only cause of a Class III skeletal pattern. However, factors like development of maxilla, length of cranial base and position of glenoid fossa are also involved in the skeletal pattern and therefore must be taken into consideration. Several classifications have been proposed to define many types of Class III malocclusion. Results and Conclusions. Angle's Classification considered only dental relationships without relating the teeth with facial and cranial bones. With the introduction of radiographic cephalometry all the three planes of space are taken into consideration. Other authors recognized the need to differentiate between dentoalveolar and skeletal discrepancies and to evaluate their relative contribution in the development of malocclusions. Delaire and Di Malta introduced the importance of muscular posture alterations (labio-mental, lingual, velo-pharyngeal) and of orofacial functions (nasal ventilation, swallowing, mastication) in the development of mandibular prognathism.