One type of orthodontic appliance that is known is a custom made plate appliance that is made in a dental laboratory and is moulded from bite impressions of the dental arches and associated dental structures of that particular patient. The bite impressions are used to make laboratory models of that particular patient's arches and associated dental structures. These models are then used to mould a customised appliance including a plate that is shaped and configured to be complementary to that particular user's dental arch and thereby closely fit that user's dental arch and arch structures.
A limitation of plate appliances is that the cost of producing them is high because they are individually made for each patient in a dental laboratory based on a dental model of the patient and a bite impression of the patient.
Orthodontic systems using fixed appliances that are commonly called orthodontic braces are also used for orthodontic treatment. Orthodontic braces comprise a plurality of brackets each of which is mounted over an individual tooth and bonded thereto so that it is permanently mounted on the tooth. The brackets are linked together by means of a wire that passes through wire apertures formed in each of the brackets. The wire applies a force to the brackets that can then reposition and align the teeth on the dental arch.
In particular these fixed appliances can be used to bring the anterior teeth on the upper and lower arches in the correct relative position to each other. The wire can progressively be drawn in to retract the incisor teeth on the anterior region of the upper dental arch to “close” an “open” bite.
These fixed appliances using brackets focus on moving teeth on a dental arch, particularly to align the teeth. For example they can be used to retract protruding teeth, in particular protruding incisors on the upper arch of a user, and they can also be used to advance retruded teeth.
The fixed appliances described above have their drawbacks. Firstly Applicant's experience is that most orthodontic patients would choose not to wear braces if an alternative treatment was available. The brackets of the braces are generally unsightly and detract from the patient's looks while the braces are being worn, e.g. for the direction of the treatment. Secondly the braces can be uncomfortable to wear and can cause trauma, such as cuts and bruises to the intraoral soft tissues of a user. The soft buccal mucosa is particularly susceptible to injury from projections on the buccal surface of the brackets.
Thirdly the brackets and wire are permanently attached to the dentition and thus cannot be temporarily removed by a patient in the way that a removable appliance can be removed. If the braces are particularly uncomfortable at any point in time to a user they cannot be temporarily removed to afford the patient some respite from the discomfort.
Fourthly another problem that has plagued the use of braces is patient relapse. By this is meant that the teeth tend to move back to their original positions once the brackets are removed. The braces are permanent appliances so that when they are removed they cease to have any influence on teeth positioning. They cannot be used on an intermittent basis to provide a retaining function after the braces have been removed in the way that a removable appliance can be used. The braces do not offer a realistic or practical option as a retainer appliance once its use as an active appliance to achieve teeth repositioning is completed.
Aside from the traditional orthodontic treatments described above, in more recent times some treatments have focused on encouraging and promoting improved myofunctional habits as a way of developing an intraoral environment that is less predisposed to the development of severe class 2 and class 3 malocclusions. For example some orthodontic practitioners have recognised that poor oral habits such as tongue thrusting, incorrect swallowing, and mouth breathing create the conditions in which a malocclusion is likely to develop in a growing child.
The applicant has developed an arch shaped appliance having a front region and two arm regions to train a patient's or user's myofunctional habits so that the environment in which arch development and teeth positioning takes place is improved. In particular the appliance can train a patient to position certain key intraoral structures such as the tongue in the correct position and thereby resist the development of malocclusions that are caused by poor oral habits. One such feature is a tongue tab that assists in positioning the tongue at the correct height and to reduce tongue thrusting. The appliance also correctly positions the lower jaw or mandible of the patient relative to the upper jaw or maxillae. The appliance also encourages the patient to maintain their lips in a closed position and not to breathe through their mouth.
These appliances are integrally formed of a soft and resilient material such as PVC or silicon rubber. The soft and resilient material enables the appliance to be comfortably worn when it bears against the dental arch and arch structures such as the teeth and gums of a patient.
As the material from which the appliance is formed is soft and flexible it is easy to deform the appliance to move the arm regions of the appliance towards and away from each other and also to bend and twist the appliance. The resilience of the material will apply a return force tending to return the appliance to its original shape when it is distorted out of its original shape.
In a case where the appliance is deformed to enable it to be fitted onto the dental arch of a patient, the resilient nature of the appliance material may cause the appliance to apply some force to the arch of a patient when it is deformed. However because the appliance material is soft and flexible it does not exert a resilient force that is strong enough to significantly develop the bone structure of the dental arch of the user. In addition such an appliance does not make a significant contribution to alignment of the dentition on the associated arch. The primary orthodontic influence conferred by the appliance is to train the patient to adopt improved myofunctional habits. These improved myofunctional habits in turn encourage the patient's dental arch to develop in a way that leads to better dental occlusion over a period of time. The development of the arch form in turn provides an environment in which alignment of the dentition can be sought using other orthodontic contrivances and techniques.
It would be advantageous if an orthodontic appliance could be devised that directed a force onto the dental arch of a patient that was capable of developing the arch form of a user. It would further be advantageous if the orthodontic appliance was capable of achieving this arch development within a reasonable treatment time.
It would be further advantageous if an orthodontic appliance could be devised that was able to positively influence dental alignment of a patient's teeth along the dental arch as well as to develop the arch form.
It would be further advantageous if such an orthodontic appliance was removable so that it could be inserted into a patient's mouth, and also be removed from the patient's mouth during the course of treatment.
It would be advantageous if an orthodontic appliance could be devised that could be manufactured in a number of sizes in a moulding operation and these sizes could then be fitted to a significant cross-section of the population. This would create the potential to manufacture the appliance on a commercial scale.