Orthodontics is the specialty involving the description and treatment of anomalies in the regular development of the masticatory system (Fig 10-1).Treatment relates to anomalies of tooth position, defective jaw development, and malocclusions, as well as abnormalities in the development of tooth germs and jaws. Maldevelopment of the dentition can be measured against statistical normal values of an optimal masticatory system. This normal dentition is a correct dentition in which the parts of the system have developed in a functional equilibrium during a process of differentiation.This process is genetically controlled, but it is supported by functional demands during chewing and altered by other influences. Therefore, the result is not always an optimal regular dentition; faulty development, referred to as dysgnathia, can arise.
The functions of orthodontics are to:
- Detect deviations from the normal course of development promptly
- Determine the extent of any faulty development
- Take suitable treatment measures
- Prevent further occlusal anomalies
- Prevent relapses after treatment is performed
- Improve masticatory and speech function
- Prevent periodontal damage and susceptibility to caries
- Improve the esthetic effect
The aim of treatment is to convert dysgnath-ias into regular dentitions and to compensate for malposition of individual teeth, deformed dental arches, or malocclusions without damaging the dentition.
Functional orthodontics involves using the functional processes during movement and loading of the masticatory system to develop the shape of the dental arches, the tooth positions, the jawbones, and the temporomandibular joints (TMJs) (Fig 10-2). Faulty development of the masticatory system is halted by orthodontic appliances and converted into regular development without the application of elastic components or external mechanical forces. The interaction between form and function is exploited to remedy malfunctions and maldevelopment of the masticatory system.
In functional orthodontics, abnormal developments of the dentition are caught at the outset and treated by exploiting growth-related, functional forces. Normalization of the form is intended to rectify function, and the form is regulated by correction of the functional processes.The mechanical mode of action of functional orthodontic appliances is based on redirecting functional muscular forces and using them as remodeling stimuli. Physiologic tissue remodeling happens without active spring components or screws.
Orthodontic appliances (based on the principle of functional orthodontics) transfer the functional influences of the musculature acting in the masticatory system to the teeth and parts of the jaw. This is done by converting vertical forces during biting into horizontal, intermittent stimuli to remodel the supportive tissue and at the same time alter the influences of the lips and tongue. The simplest principle of such an appliance is the inclined plane. Maldevelopment of form is usually accompanied by malfunction. However, isolated correction of one component (function) does not necessarily lead to correction of the other (form). In other words, achieving a change in functional processes by means of muscle training, in order to enforce changes of tooth position, will only be possible if dysfunction of the muscles was also a cause of the malposition. A variety of orthodontic treatment techniques have been established, reflecting the variety of therapeutic approaches in orthodontics.
Tooth displacement by orthodontic treatment techniques is achieved by application of force as remodeling processes are stimulated in the periodontal tissue, the alveolar jawbone, and the TMJ tissue.
Remodeling processes can be induced by functional stimuli, which originate from the muscles acting on the masticatory system. However, remodeling stimuli can also be initiated by continuous forces exerted by certain appliance designs. The treatment methods differ in terms of how much they enable orthodontic remodeling stimuli to arise in tissue, and opinions differ on the feasibility and permissibility of certain types of appliances and techniques.