Abstract

Aesthetics and Function in the Open Bite

by Grippaudo Cristina

The relationship between occlusion, malocclusion and temporomandibular disorders (TMD) is a hotly debated topic. It is very difficult to establish a cause-effect relationship between malocclusion and DTM. However, some clinical signs of malocclusion show a more frequent association with TMDs. Among these, the anterior open bite is indicated among the possible risk factors, because in the absence of an overbite and an incisive guide, patients are forced to adapt the mandibular movements during all oral functions. Patients with anterior open bite have difficulty pronouncing certain phonemes, biting and chewing, and swallowing. The functional alterations in the anterior open bite can be consequent to the presence of bad habits or find origin in the alteration of the posture and function of the tongue and in the hypotonia of the jaw elevator muscles. These are the most difficult cases to resolve, especially if associated with a hyperdivergent facial growth pattern. The alteration of the facial aesthetics resulting from the presence of the anterior open bite affects the smile line, which has less exposure of the upper incisors. Since maxillary contraction is also often associated, buccal corridors are often evident. Furthermore, the perioral muscles are contracted, and hypertonicity of the inferior orbicularis is frequently observed, which is more stressed in the effort to obtain the lip seal. The fulcrum at the molar level, for the extrusion of the molars, can determine the sliding of the mandible in the sagittal plane during growth, favoring the development of a Class 2 or a Class 3. In orthodontics, the possibilities of correcting an open bite depend on the age of the patient and on the possibility of eliminating the etiopathogenetic causes. In children, the causes can be addressed directly, and correction of the open bite can improve function and growth. In adolescents and young adults, the compensation is above all dento-alveolar, with the change of the occlusal plane due to the intrusion of the molars and the extrusion of the incisors. The change of the occlusal plane, in addition to improving the aesthetics of the smile, must take place in harmony with the mandibular function. The limit of orthodontic treatment remains the impossibility of modifying the facial structure, which can be particularly disharmonious in hyperdivergent subjects.

Learning Objectives

After this lecture, you will be able to recognize the functional causes of the open bite
After this lecture, you will be able to propose orthodontic therapies for the open bite
After this lecture, you will be able to evaluate the effects of orthodontic therapies for open bite on aesthetics and function