Realities of craniofacial growth modification.Atlas Oral Maxillofac Surg Clin North Am 2001; 9(1):23-51AO
Facial growth modification can be an effective method of resolving skeletal discrepancies. There still is much controversy regarding our understanding of the nature and extent of skeletal orthopedic change possible in individual patients and the most effective appliances and timing of such treatment. In the treatment of class II patients, growth modification can lead to an improvement, if not complete correction of the class II malocclusion. Although two-phase treatment with an early first prepubertal phase can be effective, a later single-phase approach during early puberty seems to be equally effective. Certainly, before surgical correction of the mild to moderate skeletal class II problem in a growing patient is considered, an orthopedic phase of treatment prior to the pubertal growth spurt is an appropriate first step. Skeletal class III patients with a maxillary deficiency stand to gain significant benefits from early orthopedic treatment. However, such therapy may produce more favorable changes for older children and adolescents than previously thought. Nevertheless, orthopedic correction of the mild to moderate skeletal class III should be accompanied by regular progress evaluations to avoid creating significant dental compensations in the face with little skeletal change that ultimately requires surgery anyway. Skeletal class III patients with mandibular excess and/or vertical excess are poor candidates for growth modification. Orthopedic palatal expansion appears to be effective and stable at any time prior to late puberty, a stage of development when ossification of the maxillary sutures is more advanced. Consequently, the timing for expansion may be better determined by the specific needs of each patient. A functional shift resulting from a crossbite is optimally corrected early, so that asymmetric growth of the mandible can be reduced or even prevented. Postpubertal orthopedic expansion is likely to result in bone bending, which will reverse itself over time, potentially leaving periodontal compromise of the maxillary posterior teeth. Therefore, surgically assisted expansion should be considered in such cases. Vertical maxillary excess is challenging to treat with growth modification. The combination of interocclusal acrylic bite blocks combined with a high-pull headgear presently appears to be the best means available. Unfortunately, this treatment has limited success, it must be continued over many years owing to the long-term nature of vertical growth, and it is counterproductive in achieving a balanced sagittal jaw relationship in class I or class III patients with vertical excess. Future research will permit us to have a greater understanding of the nature and extent of facial growth modification possible in individual patients and the optimal appliances and timing of treatment to achieve the best outcome. The development of intraoral osseointegrated attachments such as implants and onplants hold promise for a future means of dissipating orthopedic forces to prevent unwanted dentoalveolar changes that presently occur with our tooth-borne appliances. Analogous attachments presently are undergoing clinical testing for surgically assisted orthopedic movements associated with distraction osteogenesis.