Class II malocclusion presents a major common challenge to orthodontists. Treatment of Class II malocclusion is one of the most investigated issues in contemporary orthodontics because of the extensive variability of treatment strategies addressing the morphologic characteristics of this malocclusion. The therapeutic approaches for correcting it include tooth extractions, orthopedic appliances and extraoral or intraoral distalizing appliances. Maxillary molar distalization is one of the most common strategies to manage Class II molar occlusions. It is commonly indicated for maxillary dentoalveolar protrusion or minor skeletal discrepancies. One of the most used devices is the Pendulum appliance. Despite its efficacy for maxillary molar distalization, there are known side-effects, including labial/mesial tipping and protrusion of the maxillary incisors and premolars, distal tipping of the maxillary molars, increase in lower anterior face height, clockwise mandibular rotation, and extrusion of the first premolars. Consequently, these side-effects have to be addressed during the fixed appliance treatment phase. During the last decade, orthodontic treatment with removable clear aligners has become an increasingly common choice because of the growing number of adult patients that ask for aesthetic appliances. Vertical pattern is an essential factor in Class II treatment with molar distalization. Molar extrusion and clockwise rotation of the occlusal plane can worsen the profile and cause an open bite. Therefore, the dentoskeletal effects on vertical dimension in subjects treated with pendulum appliances followed by fixed therapy were compared with changes in a matched group treated with clear aligners. To analyze the vertical effect of the two approaches, lateral cephalograms were available before treatment (T1) and at the end of therapy (T2), with a mean interval of 2.1 years between the two observation times. The skeletal vertical dimension was not affected by the distalization of maxillary molars with aligners. The Pendulum Group showed significantly greater extrusion in both maxillary and mandibular first molar when compared with the clear aligner group. The thickness of the aligner and the resulting bite block effect could explain the absence of a significant increase in the vertical dimension and better control of the occlusal plane.
Learning Objectives:
After this lecture, attendees will be able to:
Explain the importance of vertical dimension during molar distalization, compare the pendulum appliance with clear aligners.
Provide an accurate description of effects on the occlusal plane, anterior facial height and molar extrusion at the end of treatment in Class II subjects.
Provide tips and tricks for managing molar distalization with both treatment protocols, i.e. pendulum, clear aligners.
