Class II Treatment with Clear Aligners-A Review

Abstract

Malocclusion is defined as a divergence from optimal occlusion. The type of divergence varies, but complications may be caused by any type of malalignment. Malocclusion can be skeletal or dental.¹Skeletal Class II malocclusion is a common orthodontic problem, mostly the mechanism of which is hypoplasia or retraction of the mandible². Class II malocclusions may be characterized by a protruded maxilla, retruded mandible, or both. Other variants of Class II skeletal malocclusion can be related to an increase in the length of the anterior cranial base or alterations in the vertical dimension, resulting in anteroposterior deficiencies. An increase in the anterior face height with a steep occlusal plane will also rotate the mandible backward and position the mandibular dentition into a Class II relationship.³

 Management of Class II malocclusions falls into 3 main categories: growth modification, camouflage, and surgical intervention. Growth modification is ideally 1-2 years before the peak of the growth spurt.³Differing from the epiphyseal plates of long bones, the condylar cartilage responds positively to mechanical stimulation. Therefore, for such adolescent patients, the ideal treatment method is enhancing the growth and development potential of the condyle to correct the sagittal dysregulation of both jaws and reduce the possibility of orthognathic surgery in adulthood. Functional appliance has been used to correct skeletal class II malocclusion with a history of over 100 years since Robin and Andresen found it effective in stimulating mandibular growth.²

 Growth modification may be performed using appliances such as headgear that deliver extraoral forces by redirecting the growth of the maxilla and allowing the mandible to develop further forward. Functional appliances may reposition the mandibular condyle in a more forward position within the glenoid fossa, allowing upward and backward condylar remodeling and differential tooth movement of the maxillary and mandibular molars. One of the objectives of using functional appliances in the treatment of growing patients with a Class II relationship is to eliminate functional problems such as lip trap and sucking habits, prevention of traumatic injury to proclined maxillary incisors, improve the convexity of facial esthetics, and stimulate the growth of the mandible to achieve better occlusal harmony and stability during the development of the face³

Clear aligner therapy (CAT) is an accepted part of modern orthodontic practice. Frequently cited advantages include less chair time, fewer office visits, easier oral hygiene, and an aesthetic alternative to fixed appliance therapy. Recent studies have indicated that Invisalign is one of the most used appliance globally. Invisalign (Align Technology, San Jose, Calif) uses three-dimensional technology to facilitate treatment planning and aligner fabrication processes. Align provides a digital interface, ClinCheck Pro, which enables the clinician to formulate a digital treatment plan. Once the clinician approves the plan, Align manufactures the sequence of aligners and they are sent to the clinician. Several investigations indicated that the initial DTP is routinely followed up by one or more refinement plans in which additional series of aligners are prescribed to achieve treatment objectives.⁴