Crossbite treatment at the Bethanien Center of Oral, Maxillofacial and Facial Surgery
Your dysgnathia surgery specialist in the Rhein-Main area
The most frequent growth disorder concerning width (transversal deficiency) affects the upper jaw. It is also called a narrow maxillary arch. The teeth don’t have enough space in the jaw. A clear indication for this are crooked front teeth, often in combination with displaced eyeteeth.
In the side region the narrow maxilla is shown by teeth that have tipped and turned and you find a posterior crossbite during biting, i.e. the posterior maxillary teeth do not reach over the teeth of the lower jaw. Rather, it is the other way around. If this extends also to the front teeth, it is called a circular crossbite (when the mouth is closed the maxillary teeth are not in front of the mandibular teeth but behind. A crossbite caused by a lower jaw that is too wide is rather rare.
The goal of surgery is widening upper or lower jaw, respectively, sufficiently to create space for all of the teeth without removing healthy teeth or moving teeth far out of the bone. Removals of teeth (extractions) and/or extreme movements of teeth – i.e. solely an orthodontic therapy – align upper and lower rows of teeth with each other but the narrow jaw, i.e. the bony base, remains. Both conservative variants may occasionally be nothing but poor compromises that ought to be avoided by analyses prior to treatment.
Now we want to inform you of various aspects of a classic orthodontic treatment and explain the possibilities for success of surgery.
Around the side teeth a narrow jaw is shown by tilted and convoluted teeth where biting shows a side crossbite (side teeth in the upper jaw do not reach over the teeth in the lower jaw, but vice versa). If the anterior teeth are also affected by this, it is called a circular crossbite (in the closed mouth the upper anterior teeth are not in front of the lower teeth hut vice versa). Rather rarely you find a crossbite caused by a too wide lower jaw.
lt is the surgeon’ s goal to widen the upper or lower j aw, respectively, until there is enough space for all teeth without sacrificing healthy teeth or moving teeth far out of their bone sockets. lt is true that tooth extractions and/or extreme movements of teeth (strictly orthodontic therapy) adjust the rows of upper and lower teeth but both of these conservative measures might constitute poor compromises which should be avoided with the help of analyses at the beginning of the treatment.
Conservative therapy - a poor compromise?
The orthodontic treatment by itself is a therapy that treats only the symptom of malocclusion. As a rule, there are not too many teeth but there is too little space for the customary number of 32 teeth; of course, quite often the wisdom teeth must be removed anyway due to lack of space. At first sight, treatment by tooth extractions appears simple and minimally invasive but there may be some unwanted consequences.
Esthetic aspects:
As a rule, the removal of teeth from the upper jaw causes further reduction of the dental arch, especially in the region of anterior teeth. This in turn reduces support for the upper lip resulting in a narrow long upper lip with reduced redness. In addition, it causes pronounced nasolabial folds that make the nose appear larger (large nose profile).
The removal of teeth from the lower jaw may cause a pronounced lower lip fold (submental fold).
Functional aspects:
Narrow maxillas often lead to oral breathing and obstruction of nasal breathing – an orthodontic therapy will not treat this problem.
Due to the reduced dental arch the oral cavity becomes smaller and further constricts the tongue. As a result the tongue function may permanently influence the orthodontic results so that after conclusion of the treatment malpositioning of teeth with changes of occlusion may recur. Forced bite (bite luxation) with joint compression, disc displacement and temporomandibular joint diseases may also occur.
Moving teeth out of the bone may cause the gums to degenerate. This leads to open dental necks (recessions) with increased sensitivity to heat and cold, sour and sweet tastes. In addition, the teeth look longer.
Expanding the upper jaw – a classic orthodontic treatment
Generally, the principle of distraction osteogenesis – also known as callus distraction and transversal maxillar distraction – is used for expanding the upper jaw. This procedure has also become known as “surgically assisted rapid maxillary expansion”. Distraction osteogenesis causes the formation of new localized bone (so-called callus) by mechanical dilation.
Groisman & Laube perform this operation, following a standardized and proven method, exclusively through the mouth, under anesthesia. It requires a short in-patient stay at the hospital.
Leaving the dental roots untouched, defined places of the maxilla will be carefully osteotomized by ultrasonic scalpel (piezosurgery) and thus weakened. Afterwards we insert a distractor held in place by the teeth (e.g. a hyrax screw) that the orthodontist has prepared in advance. This distractor will expand and stretch the jaw bone until the desired result has been achieved. The first turning of the screw, i.e. the first distractor movement over an established distance in the desired direction, will take place on the fourth day after surgery. The procedure will be explained and demonstrated to the patient in great detail.
As a patient you are going to receive a documentation sheet so that you can perform further turnings on your own at home. There is no need to take out sutures since the materials used for the suture dissolve automatically. During the turning stage and for a few weeks afterwards you should eat only soft foods and avoid excessive physical activities.
The extent of the expansion and the turning will be supervised by your orthodontist. The resulting dental gap will show the extent of the space gained. The turning itself is pain-free and takes around two to three weeks, depending on the space required. Afterwards the expanding apparatus will remain fixed to the teeth for four to six months in order to achieve long-term stability. If teeth are missing, we are going to use distractors anchored in the bone.
Expansion of the lower jaw – a proven method
For the so-called median mandibular distracton we are also using the principle of distraction osteogenesis. It is the counterpart of the maxillar expansion where the lower jaw is osteotomized and weakened in the middle between the central anterior teeth by ultrasonic scalpel (piezosurgery). We take care not to damage the dental roots and the mucous membranes. Both distractors supported by the teeth (e.g. a variety screw) and bone-anchored distractors will be used for dilating. The overall procedure is similar to the expansion of the upper jaw.
If a narrow jaw with matching malocclusion is diagnosed in the upper and lower jaws, the procedures of transversal maxillar distraction and median mandibular distraction may be used simultaneously.
