The vertical dimension of the maxillomandibular complex should be controlled along with horizontal and transverse correction to achieve successful orthodontic treatment of Class II malocclusion. The treatment approach in the hypodivergent Class II malocclusion should be different from the hyperdivergent Class II malocclusion treatment. In hypodivergent patients, vertical expansion of the posterior teeth is essential for improving facial esthetics with increasing vertical dimension, but this might cause backward mandibular rotation and worsen the Class II skeletal and dental relationships. This negative rotational effect of the mandible would be overcome by the muscle effects and counterclockwise growth of the mandible in the hypodivergent facial pattern. However, the stability of an increased vertical dimension has always been subject to relapse because of the muscle environment. Therefore, anchorage preparation in the mandibular arch and retention with a bite plane should be considered to obtain a stable bite opening effect for a stable increase in the vertical dimension.
Learning Objectives:
After this lecture, attendees will be able to:
Define and identify the factors influencing the vertical dimension in hypodivergent Class II malocclusion.
Understand the biomechanics for vertical control in hypodivergent Class II treatment using MIA (micro-implant anchorage) and conventional methods.
Describe and explain the contributing factors for retention and stability in hypodivergent Class II treatment.
