Who seeks surgical-orthodontic treatment: A current review

280-292 BaileyR .
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L’Tanya J. Bailey, DDS, MS Associate Professor Department of Orthodontics School of Dentistry University of North Carolina Chapel Hill, North Carolina
Leonard H. Haltiwanger, DMD, MS
Private Practice in Orthodontics Rockingham, North Carolina
George H. Blakey, DDS Clinical Associate Professor Department of Oral and Maxillofa-
cial Surgery School of Dentistry University of North Carolina Chapel Hill, North Carolina
William R. Proffit, DDS, PhD Kenan Professor Department of Orthodontics School of Dentistry University of North Carolina Chapel Hill, North Carolina
Reprint requests: Dr L’Tanya J. Bailey Department of Orthodontics School of Dentistry University of North Carolina Chapel Hill, NC 27599-7450 Fax: (919) 843-8864 E-mail:
[email protected]
Who seeks surgical-orthodontic treatment: A current review
Records for more than 2,000 individuals seen in the Dentofacial Clinic of the University of North Carolina were examined to evaluate trends in referral patterns for orthognathic surgery and acceptance of surgi- cal treatment. The vast majority of patients have been white and fe- male from the beginning, and the female-male ratio remained con- stant at 2:1 throughout the 1990s. The proportion of nonwhite patients increased significantly after 1995, with the change resulting almost totally from more Hispanic and Asian patients. The proportion of African Americans, who represent 22% of the general population, remained almost constant at 10%. Class III and long-face individuals were more likely to seek evaluation than those with Class II problems, but of those who were offered orthognathic surgery, relatively more of the Class II group accepted it. This may reflect greater severity of a Class II problem before a patient seeks treatment. More than 1⁄3 of the Clinic population had some sort of facial asymmetry, but the presence of asymmetry did not seem to influence the decision to have surgical treatment. The dental and skeletal characteristics of those who had surgery were similar to those of patients who did not have surgery, suggesting that the decision to elect a surgical treatment plan was in- fluenced by factors other than clinical characteristics. (Int J Adult Or- thod Orthognath Surg 2001;16:280–292)
When a dentofacial deformity is so se- vere that reasonable correction cannot be obtained by growth modification or cam- ouflage, a combination of orthodontics and orthognathic surgery may provide the only viable treatment option. Epidemio- logic data suggest that there are approxi- mately 1.8 million people in the United States with dentofacial disproportions too severe to be corrected by orthodontics alone.1,2 It seems likely that demand for treatment would be greater for patients with particular characteristics. A survey of some 1,000 patients who sought evalua- tion in the Dentofacial Clinic at the Univer- sity of North Carolina in the 1980s con- cluded that individuals with a Class III or long-face problem were more likely to seek and receive surgical-orthodontic treatment than those who had a Class II
problem.3 Facial asymmetry was observed in a significant number of those who sought treatment, and women were twice as likely to seek and receive treatment than men.
The climate for surgical-orthodontic treatment changed in the 1990s. From the patients’ perspective, the climate improved in several ways as significant advances in treatment occurred. For example, computer software to generate surgical predictions greatly improved communication with pa- tients and their understanding of treat- ment options, and the near-total replace- ment of maxillomandibular fixation with rigid internal fixation improves patient comfort during the postsurgical recovery period. However, the climate did also worsen for many patients, as numerous health insurance plans restricted or, in the
Int J Adult Orthod Orthognath Surg Vol. 16, No. 4, 2001
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case of Health Maintenance Organizations (HMOs), eliminated coverage for surgery.
The purpose of this study was to exam- ine the characteristics of potential surgical- orthodontic patients who sought treat- ment in the 1990s, compare them to patients seen in the 1980s, and evaluate the impact of changes in the pattern of practice on patient decisions to seek and accept treatment.
Methods
Diagnostic records for the patients who received a diagnostic evaluation through the Dentofacial Program at the University of North Carolina (UNC) between January 1990 and December 1998 (n = 811) were reviewed, as they had been for the previ- ous study that covered the period between 1979 and 1989. In addition, the entire pa- tient population of the clinic was examined in 2-year increments (from 1979 to 1998) to observe any temporal changes in selected characteristics that may have occurred. A detailed inspection was made of patients
evaluated between January 1984 and De- cember 1996 to compare those who ac- cepted a recommendation for surgery to those who rejected it. Any patient who was not offered a surgical treatment option was excluded from this group.
A statistical computer program (SAS, SAS Institute) was used to retrieve the in- formation from the database and deter- mine the prevalence (% of sample) of vari- ous characteristics of the population. Chi-square analysis was used to determine whether there were differences between the groups who accepted and rejected surgery (P < .05 indicated a statistically sig- nificant difference).
Results
Dentofacial clinic population
Demographic characteristics for the pa- tient populations of the 1980s and 1990s are shown in Table 1, and the 2-year incre- ments for the total time period are illus- trated in Figs 1 to 3. It can be seen that
Table 1 Demographic profile of dentofacial population (% of sample)
1979–1989 1990–1998 Total (n = 1,202) (n = 872) (n = 2,074)
Race
Hispanic 0.2 0.9 0.5
Other 1.2 6.4 3.3
> 35 28.8 32.2 30.3
*Very little insurance information was available before 1992.
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Fig 1 Distribution of sample by race in 2-year increments.
Fig 2 Distribution of sample by gender in 2-year increments.
Fig 3 Distribution of sample by patient age (in years) in 2-year increments.
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Table 2 Skeletal/Dental characteristics of dentofacial population (% of sample)
1979–1989 1990–1998 Total Characteristics (n = 1,202) (n = 872) (n = 2,074)
Skeletal class
Class II
Retrusive mandible 72.0 67.4 70.3
Protrusive maxilla 0.0 0.2 0.1
Both 1.4 2.6 1.8
Class III
Protrusive 28.5 11.4 20.6 mandible
Retrusive maxilla 11.8 22.0 16.5
Both 29.4 42.9 35.6
Long face
Midface 6.3 7.7 6.9
Both 12.2 15.5 13.6
Short face
Midface 4.9 11.8 7.8
Both 4.0 5.0 4.4
Asymmetry
Nose alone 21.7 21.0 21.3
Nose plus other 14.6 14.4 14.5
Other midface 4.1 2.8 3.4
Lower face 78.3 86.9 82.3
Midface and 18.6 24.1 21.5 lower face
Posterior crossbite
Unilateral 33.7 42.6 37.8
Bilateral 66.3 57.4 62.2
History of trauma 9.3 14.5 11.5
Trauma plus TMJ 4.1 7.2 5.4 symptoms
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284 Bailey et al
although the patient population remained overwhelmingly Caucasian in the 1990s, their proportion of the total decreased and the number of patients from other racial- ethnic groups increased (Fig 1). The num- ber of African Americans remained almost constant at 10%; the increase was in the Hispanic and Asian components of the population. In contrast, there was very little change in the gender distribution, which has remained about 2⁄3 female since the in- ception of the program (Fig 2). The number of older adults (greater than age 50) nearly doubled in the 1997–1998 period, while the number of patients age 20 to 29 dropped sharply after 1994. However, the proportion of patients in other age groups stayed about the same over 2 decades (Fig 3).
The distribution of patients by skeletal and dental characteristics is shown in Table 2, and the 2-year increments for selected characteristics are illustrated in Figs 4 to 8.
Although there has been a broad range of percentage variation (46% to 70%), patients with a skeletal Class II relationship were consistently more prevalent in this sample (Fig 4). Nevertheless, there has been a steady decline in the relative num- ber of Class II patients since 1981–1982. Class III patients have consistently com- prised the second most prevalent group, ranging from 20% to nearly 40% of the population. While there have invariably been fewer Class I patients, a moderate in- crease throughout the past decade il lustrates that 20% of those seeking
Fig 4 Distribution of sample by skeletal classification in 2-year increments.
Fig 5 Distribution of sample by amount of overjet in 2-year increments.
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Fig 6 Distribution of sample by amount of overbite in 2-year increments.
Fig 7 Distribution of sample by type of posterior crossbite in 2-year increments.
Fig 8 Distribution of sample by location of asymmetry in 2- year increments.
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surgical-orthodontic treatment now have a Class I skeletal pattern.
Patients with more than 6 mm of overjet have been more prevalent than those with reverse overjet, which is in accordance with the greater percentage of skeletal Class II than Class III patients (Fig 5). The percent- age of those with greater than 6 mm of overjet has ranged from 35% to 40%, while the percentage of those with reverse over- jet has ranged from 5% to nearly 20% of the clinic population. The percentage of those with greater than 5 mm of overbite and those with an open bite (reverse overbite) have been constant and equal throughout the past 2 decades, each accounting for ap- proximately 15% to 20% of the population (Fig 6). The occurrence of a bilateral poste- rior crossbite has generally remained more common than a unilateral posterior cross- bite during the past 2 decades, with the in- cidence fluctuating near 20% and 15%, re- spectively (Fig 7). However, there was a crossover between 1995 and 1998, with a higher incidence of unilateral crossbites than bilateral crossbites.
Typically, facial asymmetry has identified the lower face more than the midface (Fig 8). There has been a continuing increase in the number of patients with lower-face asymmetry throughout the past decade, nearing 35%. The prevalence of those with combined midface and lower-face asym- metry has remained relatively constant over the years (at or near 4% to 6%).
As with asymmetry, both short- and long-face problems have been identified more often in the lower face (Figs 9 and 10). The frequency of short lower-face problems has ranged from 20% to 35% of the population, while the long lower-face problems have ranged from 16% to nearly 40%. For both short-face and long-face groups, the occurrence of midface and combined mid- and lower-face problems has consistently been at or below 5% of the sample. One exception to this, how- ever, was in 1991–1992, when the reported prevalence of those with a short midface increased to 10%.
Problems and/or symptoms associated with the temporomandibular joint (TMJ) most commonly have been sounds such as clicking and crepitus (Fig 11). While the oc-
currence of TMJ sounds varied throughout the 1980s, this rate remained constant at 34% throughout the 1990s. The prevalence of reported pain symptoms has also varied. Pain reports were not collected during the first 6 years of the recorded sample, but the number of patients who reported pain increased in the late 1980s and stabilized at 20% during the 1990s. The prevalence of trauma remained within the 5% to 15% range throughout the years.
Surgery subsample
Of the 1,294 patients who were offered surgical treatment between 1984 and 1996, 544 (42%) had surgery and 750 either refused treatment or had orthodontic treatment only. The 1996 cutoff date was selected to be sure that those who had agreed to surgery would have had it, if they were really going to do so, before data col- lection for this study was completed.
Comparative data for the 2 groups are shown in Table 3. Similar to the population at large, most of the patients in this sub- sample were Caucasian. It is evident that when a surgical treatment plan was of- fered, Caucasians were more likely to ac- cept surgical treatment than African Amer- icans (P = .0036), and women were more likely to accept surgery than men (P = .0004). The skeletal Class II patients were somewhat more likely to accept surgical treatment.
A more detailed analysis of differences between those who accepted and rejected surgical treament is displayed in Table 4. In the Class II group, it appears that mandibu- lar deficiency and the degree of overjet may have affected the decision to accept or reject a surgical treatment option. Of the Class II patients who had surgery, 75% were judged clinically to have mandibular deficiency, versus 68% in the nonsurgery group, while 42% of the surgery group had an overjet of greater than 6 mm, and only 31% of those who rejected surgery had an overjet of the same degree (P = .0001). The characteristics of Class III patients who did and did not have surgery were the same, ie, those who elected to have surgery ver- sus those who did not have surgery were not significantly different regarding which
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Fig 9 Distribution of sample by short-face problems in 2-year increments.
Fig 10 Distribution of sample by long-face problems in 2-year increments.
Fig 11 Distribution of sample by type of temporomandibular joint problems in 2-year increments.
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jaw was affected or the amount of reverse overjet that existed.
Analysis of the vertical characteristics of the surgery subsample indicates that the prevalence of short- and long-face prob- lems in the group who had surgery was not dissimilar to that of the entire popula- tion (Table 4) and also was not significantly different from the group who did not have surgery (P > .05). In the patients who had surgery, the percentage of those with long lower facial height was slightly higher than that of the patients who did not have surgery.
The percentages of those with facial asymmetry in the surgery subsample were similar to the total population (Table 4). There was no appreciable difference when the group that had surgery was compared to the group that did not (P > .05). The presence of posterior crossbite was ap- proximately the same for the surgery group as it was for the total Dentofacial Clinic population (Table 4).
The prevalence of TMJ noises was the same for both the surgery group and the group that did not have surgery (Table 4). For those who did not have surgical treat- ment, the incidence of TMJ/myofascial pain was greater than those who had surgery. This suggests that the presence of pain may not have been a very influential factor in the decision to have surgical treatment. The percentages of patients with a history of trauma and trauma plus TMJ…