SURGICAL TREATMENT PHASE Mandibular Excess
Dentofacial abnormalities can frequently be’ treated IJ~ isolated procedures in the mandible or max ill.t and midface area, Because abnormalities can obviouslv OCCtI.-in both the maxilla and the niamlible, surgir;l! ‘correction
frequently requires a combination of ~lIrgicill’procedtll’l’S, -Ihe following sections describe a variety of ~urgic;l! pror= durcs completed either a~ isolated osteotomies or as combination procedures.
Final Treatment Planning
After tile completion of the presurgical periodontics, restorative dentistry, and orthodontics, the patient returns to the oral and maxillofacial surgeon’ for final presurgical planning. The evaluation completed at the initial patient examination is repeated. The patient’s facial structure and the malocclusion are reexamined. Presurgical photographs, radiographs, and presurgical
models are taken, a centric relation bite registration and face-bow recording for model mounting are completed, and computer images are obtained when available.
Model surgery on a duplicated set of presurgical dental casts determines the exact surgical movements necessary to accomplish the desired postoperative occlusion (Fig. 25-7). Prediction tracings of the anticipated surgical
movements provide a visual treatment objective of the desired skeletal movements and resulting postoperative soft tissue changes from the lateral perspective (Fig.5-8).
FIG. 25·6
FI{;, 25-?
FIG 25-8
FIG, 25-9
Presurgical Orthodontic Considerations
align the arches individually, achieve compatibility of the arches or arch segments, and establish the proper anteroposterior and vertical position of the incisors. The amount of presurgical orthodontics’ can vary, rangin,g
from only appliance placement in a few patients to . approximately 12 months of appliance therapy in those with severe crowding and incisor malposition.
Asthe patient is approaching the end of orthodontic preparation for surgery, it is helpful to take Impressions and examine the hand-articulated models for occlusal compatibility. Minor interferences that exist can be corrccted enhance the postsurgical occlusal result. After any inal orthodontic adjustments have been made. large stabilizing arch v••.ires are inserted into the brackets. which provide the strength necessary to withstand the forces resulting from intermaxillary fixation (J~:F) and surgical
manipulation.
Restorative Considerations
evaluated for carious lesions and faulty restorations. Teeth should be evaluated endodontically and periodontally for restorability, and any nonrestorable teeth should be extracted before surgical intervention. All carious lesions must be restored early inthe presurgical treatment phase, Existing restorations must function for 18 to 24 months during the orthodontic and surgical treatment phases, requiring that more durable restorative materials(i.e .. amalgam, composite resin) are used. even though
they may be ‘replaced during the definitive postsurgical treatment phase. It is wise to delay final restorative treatment until the proper skeletal relatlonships are achieved and the finishing orthodontics completed.
PRESURGICAL TREATMENT PHASE
Periodontal Considerations
As the first step in treatment, gingival inflammation mustbe controlled and the’ patient’s cooperation ensured. In patients who are unwilling or unable to clean their teeth properly before the placement of orthodontic appliances,
oral hygiene procedures will be even less effective when complicated by orthodontic band placement.
FIG. 25-5 A, Presurgical appearance of gingival tissue labial to lower anterior teeth. Inadequate
area of attachment and keratinizatlon is visualized. B, Siqniflcant improvement in attachment
and keratinization of ‘labial gingival tissue after gingival grafting
don tic movement of teeth-or a surgical procedure such as an inferior border osteotomy or segmental osteotomies in interdental areas.
EVALUATION OF PATIENTS WITH DENTOFAICAL DEFORMITY
In the past. individual practitioners often treated patients with dentofacial deformities. Some patients have been treated with orthodontics alone. with a resultant acceptable occlusion but a compromise in facial esthetics. Other patients have had surgery without orthodontics in ‘In attempt to correct a skeletal deformity, which resulted In improved facial esthetics but a less-than-id.e.al occlusion.
FIG. 25-3
Lateral cephalometric and panoramic radiographs (and posteroanterior facial ‘films and TM] films when indicated) are an important part of the initial assessment. The cephalometric radiograph can be evaluated by several techniques to aid in the determination of the nature of the skeletal abnormality (Fig. 25-4; Table 25-1).6,7 It is important to note,” however, that cephalometric radiographs are onlya part of the evaluation process. Cephaloinetric evaluation should be combined with clinical assessment of the patient’s facial structure and occlusion when the nature of the deformity is determined and possible treatment is planned. Computerized video and digital technology is currently avallab le that helps to lntegrate
the cephalometric data with digital images of the face to improve evaluation of the relationship of the
FIG. 25-4 A, Lateralcephalometric radiograph. B, Tracmq of lateral cephalometric head film, with
landmarksidentifiedfor evaluating facial,skeletal,and dental abnormalities,using system of cephalometriesfor
orthognathic surgery (see Table25-1). (8 from Burstone C) et 01: Cephalometries for orthognathic
surgery, ) Oral Surg 36:269, 1978.)
Modifiedfrom BurstoneC/ et al: Cephalometriesfor orthognathic
surgery,} Oral Surg 36:269, 1978.
•careful clinical assessment and evaluation of the diagnostic records, a problem list and treatment plan should be developed. These combine opinions from all practitjoners participating in the patient’s care, including the orthodontist, oral and maxillofacial surgeon, periodontist, and
restorative dentist.
GenetIic and Environmental Influence
Genetic Influence certainly plays a role in dentofacial deformities. Patterns of inheritance, such as a familial tendency toward a prognathic or deficient mandible, are often seen in a patient with a dentofacial deformity.
However, the multifactorial nature of facial development precludes the prediction of an inherited pattern of a particular facial abnormality.
FIG. 25-1 A, Mandibular growth resulting from apposition and resorption of bone, Primary areas 01
bony apposition include superior surface ‘of alveolar process and posterior and superior surfaces of
mandibular ramus, B, Forward and downward growth of nasal complex and maxilla in “expanding V:’
Resorption of bone at superior surface of palate occurs simultaneously with apposition at inferior surfaces
of palate and alveolar processes, In addition, growth in posterior area of maxilla results in downward
and forward expansion of maxilla. (From Enlow DH: Handbook of tilcial growth, Philadelphia,
1975, WB Saunders
~IG 25-2 Ankylosis ;esulling from trauma to temporomandibular joint. Oamaqe to condylar
growth center or limitation in function and the resulting soft tissue influence on developing
bone are responsible for resulting mandibular deficiency. A, Abnormal appearance of facial
skeleton with severe, mandibular deficiency. B, Severe class II malocclusion resulting from skeletal
abnormality.
an inuucdiatc result of trJUIIlJ. further effects on the development of fJcial bones may occur, which is most evident when ankvlosis of the mandibular condyle occurs as a result of trauma. In the CJ~e of temporomandibular
joint (I’~l.I) ankylosis ill a grO\\’illg child, alteration of growth may result from dcstructioi of the area of growth ill the T;”!J cartilage. as well as from limitntion in function. which decreases till’ influence of soft tissues on
developing hone (Fig. 25-2),
General Principles of Facial Growth
The development of proper facial form and function is a complex process af ected- by many factors. The primary sites of growth in the face and cranium are the free mar- ‘gins of the bony’ surfaces, sutures, synchondroses, and .
mandibular condyle. In the area of the craniofacial complex, reas exist’ that appear to have their own intrinsic growth potential, including the sphenooccipital and sphenoethrnoidal synchondroses and the nasal septum.
In addition. the majority of growth of the bones of the face occurs in response to adjacent soft tissue and the unctional demands placed on the underlying bone. This theory, called the functional mattix theory, explains the
dimensions of these growth patterns.
CAUSES OF DENTOFACIAl DEFORMITY
, lalocclusion and associated abnormalities ofthe skeletal components of the face can be classified as either acquired or devciopmcntat. Acquired deformities result from trauma or other external influences that alter facial morphology. Developmental deformities result from abnormal growth
of facial structures. Although it is not within the scope of this book to present a detailed discussion of facial growth, an understandingof basic principles as they relate to the development of dentofacial deformities is essential.
CHAPTER OUTLINE
‘CAUSES OF DENTOFACIAl DEFORMITY
General Principles of Facial Growth
Genetic and Environmental Influence
EVALUATION OF PATIENTS WITH DENTOFACIAl
DEFORMITY
PRESURGICAL T~EATMENT PHASE
Periodontal Considerations
Restorative Considerations
Presurgical Orthodontic Considerations
Treatment Timing
Orthodontic Treatment Objectives
Final Treatment Planning
SURGICAL TREATMENT PHASE
Mandibular ElEcess
Mandibular Deficiency
Maxillary Excess
Maxillary. and Midface Deficiency
Combination Deformities and Asymmetries
DISTRACTION OSTEOGENESIS
PERIOPERATIVE ~ARE OF THE ORTHO~NATHIC
SURGICAL PATIENT
POSTSURGICAL TREATMENT PHASE
Completion of Orthodontics
Postsurgical Restorative and Prosthetic
Considerations .
Postsurgical Dental and Periodontal Considerations
SUMMARY
ePidemiOlogic surveys demonstrate that a large per-
– centage of the United States’ population has a significant
malocclusion. Many of these cases are
severe enough to affect facial proportions, and approxi-
-mately 5% may be classified ashandlcapplng.!
Approximately 10% of the populatlon has a class U malocclusion, 1% of which require surgical advancement of the mandible to correct the skeletal deficiency. A small percentage of the population requires surgical correction of anteroposterior maxillary excess to treat their class II
malocclusions most satisfactorily, Class III malocclusions occur in 2.5% of the population, with 40% of these cases being severe enough to require surgical correction toobtain the best occlusal and esthetic result. In many classIII malocclusions, the deformities can be attributed to
abnormal skeletal position of the mandible: however, nearly 50% may be at least partially caused by maxillary deficiency. ‘
Historically treatment of dentofacial deformities has been aimed’ at correction of dental abnormalities, with little attention to the accompanying deformity of the facial skeleton. In the last 40 years, surgical techniques have been developed to allow positioning of the entire
midface complex, mandible, or dentoalveolar segments to any desiredpositlon. The combining of surgical and orthodontic procedures for dentofacial deformities has ecome an integral part of the correction of malocclu– sions and facial abnormalities. ‘