The most common growth disorder in width (known as the transverse dimension) affects the upper jaw, often referred to as a narrow upper jaw. The teeth do not have enough space to align correctly. This is typically visible through crowded or crooked front teeth, frequently accompanied by protruding canines.
In the posterior region, the narrow jaw may cause tooth tilting or rotation, leading to a lateral crossbite. This means that the upper teeth bite inside the lower teeth instead of outside, as they should. When the front teeth are also affected, the condition is called a circular crossbite (when the mouth is closed, the upper teeth are positioned behind the lower ones). In rarer cases, a crossbite can be caused by an overly wide lower jaw.
The surgical goal is to widen the upper or lower jaw sufficiently to create enough space for all teeth. Our approach avoids removing healthy teeth or moving them excessively out of the bone. In contrast, treatments involving tooth extractions and/or extreme orthodontic movement—meaning purely orthodontic therapy—merely adapt the dental arches without addressing the underlying narrow jaw. This approach disregards facial aesthetics. Both conservative methods can represent poor compromises, which can be avoided through careful analysis before treatment begins.
Below, we provide an overview of classical orthodontic treatment approaches and explain the potential success of surgical correction.
Conservative Crossbite Therapy — a Poor Compromise?
Purely orthodontic treatment represents a symptomatic approach, meaning it addresses only the visible effects of the misalignment. Typically, the issue is not too many teeth but insufficient space for the normal set of 32. In such cases, wisdom teeth are often removed due to lack of room. At first glance, this approach may seem simple and minimally invasive, but tooth extractions can lead to undesirable secondary effects. What are the aesthetic considerations? The removal of teeth in the upper jaw usually results in further narrowing of the dental arch, particularly in the front tooth area. This reduces the support for the upper lip, leading to a long, narrow upper lip with less visible lip tissue. In addition, pronounced nasolabial folds may develop, which can make the nose appear larger (a so-called *prominent nasal profile*). What are the functional aspects? Mouth breathing, often caused by a narrow upper jaw and associated with nasal obstruction, is typically not addressed through orthodontic therapy alone. A smaller dental arch results in a reduced oral cavity and limited tongue space. This can have a long-term impact on tongue function and consequently affect the orthodontic outcome. As a result, after treatment, misalignments or bite irregularities may reappear. These may include a forced bite with jaw joint compression, disc displacement, and related temporomandibular joint (TMJ) disorders. Moving teeth too far out of the bone can also lead to gum recession, exposing the tooth necks. This increases sensitivity to heat, cold, and sweet or sour stimuli. The teeth may also appear visually longer. Widening of the Upper Jaw: A Classic Orthognathic Procedure The widening of the upper jaw typically follows the principle of *distraction osteogenesis*, also known as *callus distraction* or *transverse maxillary distraction*. This technique, commonly referred to as *surgically assisted rapid palatal expansion*, promotes the formation of new, stable bone (so-called callus) through mechanical separation. At Groisman & Laube, this procedure is performed under general anaesthesia using a well-established and standardised technique, carried out entirely through the mouth. It usually involves a short inpatient stay. During the operation, we make controlled osteotomies at predefined locations, carefully protecting the tooth roots using an ultrasonic scalpel (piezosurgery). We then insert a tooth-borne distractor (e.g. a Hyrax screw device) that has been custom-made by the orthodontist beforehand. The distractor gradually expands and stretches the upper jaw bone until the desired width is achieved. On the fourth postoperative day, the device is activated for the first time and turned at fixed intervals in the planned direction, with the entire process clearly explained and demonstrated to the patient. As a patient, you will receive a documentation sheet allowing you to continue the turning process independently at home. Suture removal is not required, as we use self-dissolving materials. During the activation phase and for a few weeks afterwards, you should maintain a soft diet and avoid excessive physical activity. The degree of expansion and the adjustment process are monitored by your orthodontist. The gap that forms between the teeth indicates the amount of space gained. The activation process itself is painless and typically lasts about two to three weeks, depending on the required expansion. The appliance remains attached to the teeth for approximately four to six months to ensure a long-term stable result. If teeth are missing, bone-anchored distractors are used. Widening of the Lower Jaw: A Proven Method The so-called *median mandibular distraction* also uses the principle of distraction osteogenesis. It serves as the counterpart to upper jaw expansion. The lower jaw is surgically divided in the midline between the central incisors --- using an ultrasonic scalpel (piezosurgery) to protect the tooth roots and soft tissues --- and gently weakened. For the expansion, both tooth-borne distractors (such as a Variety screw device) and bone-anchored distractors can be used. The overall procedure mirrors that of the upper jaw widening. If a narrow jaw is diagnosed in both the upper and lower arches, accompanied by malocclusion, the *transverse maxillary distraction* and *median mandibular distraction* can be performed simultaneously.
