SOMA Appliances

SOMA (Splint Orthodontic Myofunctional Appliance)

The SOMA combines different methods to correct a range of problems associated with the faulty development of the bones of the face and head. These problems include facial imbalance, malocclusion, a deep or narrow palate and a variety of pathological conditions associated with misalignment of the cranial structures. Typically, these conditions result in pain that involves the head, neck and spine. For many, the SOMA enables the jaw to come forward, the lips to close together, breathing through the nose and relaxation of the chin and throat. It is designed to facilitate myofunctional changes first and orthodontic movement second.

DESCRIPTION

The SOMA is constructed from low allergy acrylic and nickel free wire. A Schwartz screw is used, giving it three way expansion. The teeth can move in six possible directions making the SOMA a very functional treatment option. It works by decompressing the joints using platforms, lowers the TMJ and inhibits the locking of the temporal and frontal bones, giving the sphenoid freedom of movement.

Where necessary, spring retractors are also incorporated into the construction of the appliance. There are a variety of add on features that can be incorporated into the appliance including brackets and elastics. Judgements as to when it is appropriate to incorporate such features will, ultimately, be at the practicing dentists' discretion.

There is space between the acrylic plate and the palate so that the pressure is exerted against the palate through the teeth. This loads the plate, forcing the tongue to press harder against the upper palate, thus facilitating its expansion. Force is transmitted through the maxilla, through the palatine bones into the sphenoid and the skull.

Wire around the teeth allows the teeth to be moved bodily, preventing tipping. Tipping (the tipping movement of the teeth rather than the suture movement) results from expansion that happens too quickly. The design of the wires and the clasp do not jam up the teeth or the maxilla. The aim is to correct the vertical, transverse and
anterior/posterior architecture of the mouth and to bring about balance in all its associated structures.

Retention is an important factor. In specific instances, modification can be made on the teeth by use of composite to allow for a firm fit. The acrylic can be adjusted allowing pressure to be applied to specific teeth.

WHAT DOES THE SOMA DO?

Upper Standard Type 1 appliance

The upper standard appliance has a labial arch wire, acrylic, a screw and an anterior platform. It is generally used for cases where there is a deep bite or retruded mandible. It can be used for unerupted teeth, deciduous and permanent teeth in children. For type 1, it is the labial bow that makes it distinct from the type 2 and 3 upper standard.

The upper standard type 1 has a three way Schwartz screw that can be adjusted at each of the three sides. It has a labial bow which can go to the back of the last molar or across and between the first and second molar, which is free and joined to the acrylic in such a way that it does not compress the incisive, maxillary or palatine sutures or lock up the cranium. The labial bow assists in part of the retention while also it helps to move teeth. The type 1 upper standard appliance is useful in cases where teeth are erupting and when there are deciduous teeth.

The type 1 upper standard can be used on patients even when they are having amalgams removed, crowns or fillings done. The appliance can still fit properly and not interfere with such restorations.

What variations can be made to the type 1 upper standard?

Springs can be used to push the laterals anteriorly or proximally. The spring is attached to the acrylic to push out teeth that are in cross bite. A spring can be used to push or pull in the canines that are buccally placed; the spring can be positioned from the wire or from the acrylic.

Platforms

For the type 1 upper standard you can have an anterior platform, anterior-posterior platform or just a posterior platform.
The only draw back with the type one upper standard is that the wire is not aesthetically pleasing. It has a tremendous effect on settling the Startle reflexes like the Moro appliance.

Type 2 Upper Standard

There are two sub types of the type 2 upper standard appliance; either with or without the labial bow. The type 2 has a U type shape with buccal retention. The forces applied with the type 2 are same as the type 1 in that the pressure is applied to the teeth very slightly which opens up the sutures and the acrylic is positioned slightly away from the upper palate. The acrylic can be adjusted by trimming to change the position where the force is applied.

Using the type 2 upper standard to expand the mouth can change the vertical dimension of the mouth, because the lower jaw is moving anteriorly and the lower posterior teeth are erupting, flattening the curve of Spee. The erupting teeth must be monitored so that they don't over-erupt. In that situation a suitable posterior platform can be used to stop the eruption of teeth. A platform can be added at any time. You can start with an anterior platform and then grind the anterior platform down so you don't get over-eruption of the lower teeth, or you can add a posterior platform to stop the eruption of the posterior teeth.

The case selection criteria for the type 2 are the same as type 1, however, you would not use the type 2 for young children, because teeth are already erupting and where it is preferable to have circumferential retention that does not compress the palatal sutures and allows teeth to erupt freely. Type 2 can be used for adults and people who are more concerned with aesthetics and who need to talk very clearly whilst wearing the appliance.

Type 3 Upper Standard appliance

This appliance has three separate individual screws; the anterior screw is widening the palate transversely and the posterior screws to widen the jaw in the anterior posterior direction. There is also transverse expansion with the middle screw. The combination is able to distalise teeth by moving the suture anteriorly, and is also useful when the canine teeth are buccally placed. It is mainly used where teeth need to be distalised, for that reason this appliance is also recognised as the distaliser. It allows for more sagittal expansion of the teeth.

The type 3 upper standard appliance has a similar retention to the type 2 upper standard appliance with the U loop and buccal clasp. There are two sub-types, with or without a labial bow. The distinguishing features of the type 3 upper standard appliance are three separate screws and expansion process of the acrylic, different from the normal three-way expansion screw found in the type 1 and 2 upper standard appliances. The advantage of the three separate screws is to allow you to control certain variables. If on one side there is lack of room, you can develop that one side while leaving the other side alone.

The type 3 upper standard could be considered the universal appliance because it can be used in all cases, although it is a little bit more expensive because of the multiple screws.

Lower standard appliance

There is only one type of lower appliance which has been designed to increase the rate of expansion of the lower jaw to maintain a proper match between the upper teeth and the lower teeth. The lower standard allows achievement of an edge-to-edge bite at a faster rate in class 2 relationships. The lower standard appliance also removes malocclusion and makes more room for the tongue.

The lower appliance can have a posterior platform but there is usually no anterior platform. Most of the time, the lower appliance does not have a posterior platform. The only time a lower posterior platform is necessary is for an open bite case or the need to intrude upper molars.

A lower platform can be used similar to a pivot or a Gelb type appliance when you want to stabilise the TMJ while not wearing an upper appliance. It allows for easier speech and can decompress the TMJ and expand the lower jaw. This appliance can be used for all cases (eg classes I, II and III)

The lower appliance does not come with an outside wire. It has a U type clasp, with buccal acrylic retention and acrylic on the lingual aspect. The acrylic also allows the tongue to rise upwards towards the palate and also push on the teeth to widen the jaw.

Through the expansion process, the teeth become as close to edge-to-edge as is possible.
For further information on the SOMA, please email Dr Joseph Da Cruz at qbn@wholisticdentistry.com.au