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Early orthodontic treatment
VIEWPOINT
Early orthodontic treatment Donald R. Joondeph, DDS, MS*
Interception by definition means "to stop, deflect, or interrupt the progress or intended course." The objective of interceptive orthodontic supervision is to create a more normal dentofacial environment as early as possible to prevent the adaptations and limitations that are often associated with a significant malocclusion in late adolescence. The question is not "what can be treated early?" but rather "what shotdd be treated early?" There are hidden pitfalls associated with interceptive treatment that may include long treatment times, maintenance of appliances, inability to accurately anticipate the changes associated with dentofacial growth and development, and the necessity to closely monitor treatment progress to avoid irreversible occlusal changes while evaluating the treatment response. The clinician must be prepared to evaluate and to alter the original plan of treatment if patient response is not coincident with treat" ment objectives. Problem list and treatment plan development in the young patient is demanding as there are many variables to consider, many of which are difficult to predict or control. The clinician must have an understanding of the dentofacial changes associated with various growth patterns to identify the cause of the malocclusion, to determine treatment objectives and options, and to select the appropriate appliance to reach those objectives. One goal of early intervention should be the prevention of progressive, irreversible soft iissue or bony changes. In developing arch length deficiency malocclusions, for instance, serial extraction procedures, guidance of eruption, or active appliance therapy can be instituted early to create or to preserve arch length with' the objective of encouraging the dentition to erupt into a more ideal arch form. There is evidence, for instance, to suggest that teeth that erupt ectopically, out of attached gingival tissue, will exhibit long-term decreases in both attached tissue thickness and alveolar bone height when compared with normally erupting controls. Another example of a potentially progressive change is a functional mandibular deviation from rest
*Associate Professor, Department of Orthodontics, Universityof Washington, Seattle, Wash.
position or centric relation into maximum intercuspation. Such a functional shift may also be associated with concomitant soft tissue dysfunction of the temporomandibular joints (TMJs) and may progress to internal derangement and, in some cases, even degenerative changes of the TMJs if left untreated. These derangements, although multicausal in etiology, can often respond favorably to early restoration of normal joint function decreasing the likelihood of further progressive change. Early treatment also offers the potential to improve skeletal malrelationships by influencing the increment and direction of facial growth. For instance, in the treatment of a skeletal Class II mal0cclusion, either fixed or removable appliances may be used to restrict or redirect anterior maxillary development allowing normal mandibular growth to correct this anteroposterior disharmony. In addition, variations in appliance design and application can often alter growth direction to assist in the resolution of anteroposterior discrepancies and to control or correct vertical facial disharmonies. Maxillary protraction appliances have also been shown to be somewhat effective in the treatment of Class III skeletal malocclusions as a result of maxillary deficiency. Although the long-term benefits of such therapy remains inconclusive, it is well established that treatment must be instituted very early, in the range of 4 to 5 years of age, to more efficiently gain skeletal maxillary advancement as opposed to dentoalveolar change. Alteration of dentoalveolar development through control of differential tooth eruption is also often a-~ treatment objective and forms the basis of various type s of therapy, most notably removable or "functional" appliances. For instance, Class II correction with a bionator has as its objective maintenance of maxillary buccal segment vertical position while encouraging the man. dibular arch to enapt upward and forward into a Class I intercuspal relationship. This type of therapy is certainly only effective when the patient is undergoing facial growth with concomitant active dental eruption as the clinician "guides" or "controls" the existing eruption process. After cessation of growth, however, significant limitations are introduced when attempting to correct a malocclusion by differential tooth eruption. 199
'
200
Viewpoint
Vertical tooth movement in a nongrowing patient may result in irreversible iatrogenic occlusal changes both transversely and anteroposteriorly. Interception should also be considered before excessive dental and skeletal compensations that result from skeletal or functional disharmonies. For instance, investigators have suggested that chronic nasal obstructions, such as allergic rhinitis, may be associated with an adaptive low, anterior tongue posture and mouth breathing. These compensatory tongue and breathing patterns may contribute to altered dentofacial growth patterns characterized by vertical facial development, maxillary constriction with high palatal vault, and open bite dental pattem. Early identification of this potential problem with restoration of a patent nasopharynx in combination with appliance therapy to improve dentofacial relationships may reduce the progressive nature of these changes. An example of dental compensation secondary to a skeletal disharmony is often seen in the skeletal Class II malocclusion. Because o f the tapered form of the arches, the maxillary buccal s~gments erupt occluding against a narrower portion of the mandibular arch. This "compensatory" maxillary constriction may require sutural expansion in the later adolescent years to gain a more ideal maxillary skeletal width for proper buccal segment torque. Early resolution of the anteroposterior discrepancy could have allowed more normal lateral development of the maxilla and a reduction in the treatment complexity. If left untreated, compensatory changes may become so severe that these compensations could have greater treatment limitations than correction of the primary defect alone. In fact, in cases with severe skeletal discrepancies that are being planned for future orthog-
American Journal of Orthodontics and Dentofacial Orthopedics August 1993
nathic correction, the early or mixed dentition treatment mechanics should be directed toward preventing compensations from being fully expressed rather than treating the primary skeletal defect. This approach will eliminate the need for future extensive presurgical decompensation and allow achievement of a more ideal surgical result, when growth has been completed. Underlying skeletal deformities may require .orthopedic changes to gain the more ideal maxillomandibular relationship needed to achieve a satisfactorily functioning occlusion. It is often necessary to correct these skeletal malrelationships while craniofacial sutures are structurally immature and more amenable to alteration. A bilateral maxillary constriction with adat~tive mandibular functional shift into a buccal segment crossbite is an example of this type of disharmony. Investigators have shown that the midpalatal suture remainspatent until at least the third or fourth decade of life. However, once maturation is complete, sutures no longer function as active adjustment sites for growth and become more intercuspated forming mechanical "locks." This alteration in sutural structure makes sutural expansion procedures more difficult and may result in a greater degree of dental movement rather than the desired skeletal change. Early mechanotherapy, while the suture is still adaptive, may provide the clinician with an opportunity to more easily achieve skeletal alteration while improving long-term stability. The institution and timing of early orthodontic supervision carries with it the challenge of anticipating the changes associated with facial growth, dental development and patient response. If these challenges can be met with sound problem list development and treatment goals, there is a handsome reward for both the patient and practitioner.
Early orthodontic treatment Donald R. Joondeph, DDS, MS*
Interception by definition means "to stop, deflect, or interrupt the progress or intended course." The objective of interceptive orthodontic supervision is to create a more normal dentofacial environment as early as possible to prevent the adaptations and limitations that are often associated with a significant malocclusion in late adolescence. The question is not "what can be treated early?" but rather "what shotdd be treated early?" There are hidden pitfalls associated with interceptive treatment that may include long treatment times, maintenance of appliances, inability to accurately anticipate the changes associated with dentofacial growth and development, and the necessity to closely monitor treatment progress to avoid irreversible occlusal changes while evaluating the treatment response. The clinician must be prepared to evaluate and to alter the original plan of treatment if patient response is not coincident with treat" ment objectives. Problem list and treatment plan development in the young patient is demanding as there are many variables to consider, many of which are difficult to predict or control. The clinician must have an understanding of the dentofacial changes associated with various growth patterns to identify the cause of the malocclusion, to determine treatment objectives and options, and to select the appropriate appliance to reach those objectives. One goal of early intervention should be the prevention of progressive, irreversible soft iissue or bony changes. In developing arch length deficiency malocclusions, for instance, serial extraction procedures, guidance of eruption, or active appliance therapy can be instituted early to create or to preserve arch length with' the objective of encouraging the dentition to erupt into a more ideal arch form. There is evidence, for instance, to suggest that teeth that erupt ectopically, out of attached gingival tissue, will exhibit long-term decreases in both attached tissue thickness and alveolar bone height when compared with normally erupting controls. Another example of a potentially progressive change is a functional mandibular deviation from rest
*Associate Professor, Department of Orthodontics, Universityof Washington, Seattle, Wash.
position or centric relation into maximum intercuspation. Such a functional shift may also be associated with concomitant soft tissue dysfunction of the temporomandibular joints (TMJs) and may progress to internal derangement and, in some cases, even degenerative changes of the TMJs if left untreated. These derangements, although multicausal in etiology, can often respond favorably to early restoration of normal joint function decreasing the likelihood of further progressive change. Early treatment also offers the potential to improve skeletal malrelationships by influencing the increment and direction of facial growth. For instance, in the treatment of a skeletal Class II mal0cclusion, either fixed or removable appliances may be used to restrict or redirect anterior maxillary development allowing normal mandibular growth to correct this anteroposterior disharmony. In addition, variations in appliance design and application can often alter growth direction to assist in the resolution of anteroposterior discrepancies and to control or correct vertical facial disharmonies. Maxillary protraction appliances have also been shown to be somewhat effective in the treatment of Class III skeletal malocclusions as a result of maxillary deficiency. Although the long-term benefits of such therapy remains inconclusive, it is well established that treatment must be instituted very early, in the range of 4 to 5 years of age, to more efficiently gain skeletal maxillary advancement as opposed to dentoalveolar change. Alteration of dentoalveolar development through control of differential tooth eruption is also often a-~ treatment objective and forms the basis of various type s of therapy, most notably removable or "functional" appliances. For instance, Class II correction with a bionator has as its objective maintenance of maxillary buccal segment vertical position while encouraging the man. dibular arch to enapt upward and forward into a Class I intercuspal relationship. This type of therapy is certainly only effective when the patient is undergoing facial growth with concomitant active dental eruption as the clinician "guides" or "controls" the existing eruption process. After cessation of growth, however, significant limitations are introduced when attempting to correct a malocclusion by differential tooth eruption. 199
'
200
Viewpoint
Vertical tooth movement in a nongrowing patient may result in irreversible iatrogenic occlusal changes both transversely and anteroposteriorly. Interception should also be considered before excessive dental and skeletal compensations that result from skeletal or functional disharmonies. For instance, investigators have suggested that chronic nasal obstructions, such as allergic rhinitis, may be associated with an adaptive low, anterior tongue posture and mouth breathing. These compensatory tongue and breathing patterns may contribute to altered dentofacial growth patterns characterized by vertical facial development, maxillary constriction with high palatal vault, and open bite dental pattem. Early identification of this potential problem with restoration of a patent nasopharynx in combination with appliance therapy to improve dentofacial relationships may reduce the progressive nature of these changes. An example of dental compensation secondary to a skeletal disharmony is often seen in the skeletal Class II malocclusion. Because o f the tapered form of the arches, the maxillary buccal s~gments erupt occluding against a narrower portion of the mandibular arch. This "compensatory" maxillary constriction may require sutural expansion in the later adolescent years to gain a more ideal maxillary skeletal width for proper buccal segment torque. Early resolution of the anteroposterior discrepancy could have allowed more normal lateral development of the maxilla and a reduction in the treatment complexity. If left untreated, compensatory changes may become so severe that these compensations could have greater treatment limitations than correction of the primary defect alone. In fact, in cases with severe skeletal discrepancies that are being planned for future orthog-
American Journal of Orthodontics and Dentofacial Orthopedics August 1993
nathic correction, the early or mixed dentition treatment mechanics should be directed toward preventing compensations from being fully expressed rather than treating the primary skeletal defect. This approach will eliminate the need for future extensive presurgical decompensation and allow achievement of a more ideal surgical result, when growth has been completed. Underlying skeletal deformities may require .orthopedic changes to gain the more ideal maxillomandibular relationship needed to achieve a satisfactorily functioning occlusion. It is often necessary to correct these skeletal malrelationships while craniofacial sutures are structurally immature and more amenable to alteration. A bilateral maxillary constriction with adat~tive mandibular functional shift into a buccal segment crossbite is an example of this type of disharmony. Investigators have shown that the midpalatal suture remainspatent until at least the third or fourth decade of life. However, once maturation is complete, sutures no longer function as active adjustment sites for growth and become more intercuspated forming mechanical "locks." This alteration in sutural structure makes sutural expansion procedures more difficult and may result in a greater degree of dental movement rather than the desired skeletal change. Early mechanotherapy, while the suture is still adaptive, may provide the clinician with an opportunity to more easily achieve skeletal alteration while improving long-term stability. The institution and timing of early orthodontic supervision carries with it the challenge of anticipating the changes associated with facial growth, dental development and patient response. If these challenges can be met with sound problem list development and treatment goals, there is a handsome reward for both the patient and practitioner.