Acculturation levels and personalizing orthognathic surgery for the Asian American patient

Abstract

This study was performed to investigate whether the level of acculturation among Asians living in the USA plays a significant role in their opinion of facial profiles. One hundred and ninety-eight Asian American subjects were asked to complete a pre-validated survey to measure their level of acculturation and to evaluate four sets of pictures that displayed a class II male, class II female, class III male, and class III female. Each set consisted of three lateral profile pictures: an initial unaltered photo, a picture simulating a flatter profile (orthodontic camouflage in class II; mandibular setback in class III), and a picture simulating a fuller profile (mandibular advancement in class II; maxillary advancement in class III). For the class II male, subjects who were more acculturated indicated that a flatter profile (orthodontic camouflage) was less attractive. For the class II female, higher acculturated subjects chose expansive treatment (mandibular advancement) as more aesthetic compared to the less acculturated subjects. Each of these scenarios had statistically significant odds ratios. In general, highly acculturated subjects preferred a fuller facial profile, while low acculturated subjects preferred a flatter facial profile appearance, except for the class III female profile, which did not follow this trend.

The face is a complex product of skeletal anatomy, soft tissue drape, and interdental relationships. Any surgical intervention in this region must be met with not only understanding of the aesthetic repercussions of bony/soft tissue changes, but also with a judicious and nuanced grasp of the cultural and personal preferences of the patient. This vital connection between patient and provider is important, because the cultural background affects both how health care workers administer care and how patients choose to receive this treatment. Hence, the delivery of care and the patient’s expectations must be aligned within the context of their respective cultural milieu. Given the delicate nature of any surgical procedure that affects facial appearance, ethnic-specific approaches and modifications must be tailored to each individual patient.

In general, the Asian facial profile is described as flat or straight with full upper and lower lips, while Caucasian profiles are more classically thought of as fuller and projected with more anteriorly positioned lips. This is important because the surgical correction of sagittal jaw discrepancies can be approached in more than one way. Often times, the decision is dictated by the treating surgeon and orthodontist, guided by their clinical experience and personal biases.

Lee and colleagues recently reported that oral and maxillofacial surgeons trained in different countries treat aesthetic profiles differently. When shown profiles of Asian models, surgeons who were trained in the USA (acculturated to Western culture) recommended treatment that favoured a fuller profile, while those who were trained in Asia were more likely to prefer a flatter profile and recommend surgical treatments according to their aesthetic preferences. A potential explanation was that most American surgeons were trained by Caucasian surgeon-educators and learned cephalometric analysis using Caucasian norms. American culture assumes the Caucasian aesthetics as the norm, which may influence surgeon perceptions and treatment of Asian patients. There was also notable gender segregation, with most surgeons recommending advancement surgeries for male compared to female subjects. Similarly, various cultures have contrasting definitions of what is considered attractive. Therefore, cultural and personal preferences must play a central role when determining the final treatment plan. A result that may be aesthetically pleasing to the surgeon may not be the case from the patient’s perspective.

The aim of this study was to investigate whether the level of acculturation (the process in which members of one cultural group adopt the beliefs and behaviours of another group) among Asians living in the USA plays a significant role in their opinion of various facial profiles. It was hypothesized that highly acculturated individuals would prefer a Westernized profile or treatment plan, while less acculturated individuals would not have this preference. This is a crucial area of study to explore because there is no objective scale to examine the Asian American patient’s level of acculturation with their profile preference. This is especially important in an era of unprecedented growth in the Asian population globally and in the USA. As of 2010, there were 14.6 million Asian Americans living in the USA and that number will increase substantially in the coming years as Asian immigrants replace Hispanics as the fastest growing racial group in the USA. Each Asian living in the USA will have different levels of acculturation and likely varying facial aesthetic preferences. The results of this study will bridge the gap between clinician–patient perceptions, determine the impact of acculturation on aesthetic preferences, and potentially result in improved patient satisfaction, as the treatment plan may be tailored with culture, preference, and perception in consideration.

Materials and methods

Study design and subjects

This was a cross-sectional survey study of Asian Americans aged between 18 and 45 years. Subjects were approached directly in person at their university or local cultural community centres. Approval to conduct this study was obtained from the necessary institutional review board. Subjects were randomly approached by the study recruiters on campus and at local centres to explain, distribute, and collect the survey. All subjects provided informed consent and had the option to opt out of the study at any point prior to completion of the survey. To be included in this study, subjects had to be East Asian Americans who were not trained in and did not have a background in soft tissue facial profile analysis or orthodontic/surgical treatment planning and had to be able to complete a survey in English.

Survey formulation

Subjects were asked to complete a short survey that was composed of two parts (Fig. 1). The first part of the survey incorporated the Suinn–Lew Acculturation Questionnaire, which is a pre-validated set of questions that is utilized globally to measure a person’s acculturation level to a specific culture. Approval was obtained from Suinn and Lew to use the questionnaire in this study. This survey contains 21 questions pertaining to the subject’s cultural background, with responses to the questions based on a scale of 1–5; 1 represents the least American-acculturated and 5 represents the most American-acculturated. Acculturation scores were an average of the response per subject, and they were stratified based on their acculturation level ( Table 1 ). Six additional demographic questions were included: age, gender, level of education, ethnicity, length of residency in the USA, and occupation.

Table 1
Average score with corresponding acculturation level.
Average score ( x ) Acculturation level
x = 1 None
1 < x < 2 Low
2 ≤ x < 3 Moderate
3 ≤ x < 4 High
4 ≤ x < 5 Full

The second part of the survey was the facial aesthetic preference survey, which contained four sets of pictures. These four sets of pictures displayed a class II male (retrognathic mandible), class II female (retrognathic mandible), class III male (prognathic mandible), and class III female (prognathic mandible) – all were of East Asian descent and had cephalometrically diagnosed class II or III. Each set consisted of three lateral profile pictures: an initial unaltered photo, a digitally modified picture simulating a flatter profile (orthodontic camouflage in class II and mandibular setback in class III), and a digitally modified facial profile simulating a fuller profile (mandibular advancement in class II and maxillary advancement in class III). Dolphin imaging software (Patterson Dental, Chatsworth, CA, USA) was used to create these simulations via its surgical prediction module, except for the class II female for which an actual post-treatment result with orthodontic camouflage and postured mandibular advancement were shown for the proposed movements. The participants were then asked to rank the pictures in each set with ordinal preference, 1 being the most attractive and 3 being the least attractive ( Figs. 2–5 ).

Fig. 2
Images and simulation of the class II male: original (centre), orthodontic camouflage via extraction simulation (left), mandibular advancement simulation (right).

Fig. 3
Images and simulation of the class II female: original (centre), orthodontic camouflage via extraction simulation (left), mandibular advancement simulation (right).

Fig. 4
Images and simulation of the class III male: original (centre), mandibular set back simulation (left), maxillary advancement simulation (right).

Fig. 5
Images and simulation of the class III female: original (centre), mandibular set back simulation (left), maxillary advancement simulation (right).

Statistical analysis

All data from the survey were entered into the statistical program Stata ver. 12.1 (StataCorp, College Station, TX, USA). Descriptive statistics were used to evaluate the subject pool, and positive or negative correlation strength was measured by Pearson’s R . No subject had an average acculturation score of 1 (demonstrating no acculturation) or ≥4 (demonstrating complete acculturation), thus acculturation was stratified into three levels: low acculturation (1 < x < 2), moderate acculturation (2 ≤ x < 3), and high acculturation (3 ≤ x < 4). For both acculturation level and facial aesthetics, the data were ordinal, rank, in format. Due to this unique data format it was not possible to conduct the more common logistic regression models used for binary (yes and no) data. To analyze the ordinal dataset, ordered logistic regression was used; however the proportional odds assumption has to be assumed, such that each tier is proportionally similar to each other (highest attractiveness rank 1 and lowest attractiveness rank 3). An odds ratio of <1 would indicate that more acculturated subjects had higher odds of selecting a particular profile as attractive compared to less acculturated subjects. An odds ratio of >1 would indicate that more acculturated subjects had higher odds of selecting a particular profile as unattractive compared to less acculturated subjects. For each derived odds ratio (OR), both the P -value and the 95% confidence interval (95% CI), to show the range of values for each profile, are presented. A P -value of <0.05 was considered statistically significant.

Results

Demographics and acculturation level of the subjects

A total number of 198 subjects completed the survey questionnaire; 100 were female and 98 were male. The average age was 24.9 years for both female and male subjects, and the average time of residency in the USA for the female and male groups was 19.6 years and 19.7 years, respectively ( Table 2 ), with no statistical difference. The subjects had varied levels of education, with the most common level achieved being undergraduate education among female and male subjects; there was no statistical difference between the genders ( Table 2 ). The majority of subjects were students and there was great diversity in occupation, but none were health professionals with a background in facial aesthetics or orthognathic treatment planning. Of the 198 subjects, 124 were born in the USA or were living in the USA prior to 1 year of age. The subjects self-identified their ethnicity as Chinese ( n = 127), Korean ( n = 25), Japanese ( n = 10), Filipino ( n = 19), or other ( n = 8); nine subjects did not respond to this question.

Table 2
Demographic data of the subjects ( N = 198).
Female n = 100 Male n = 98
Age in years (mean ± SD) 24.9 ± 5.8 24.9 ± 5.6
Years in USA (mean ± SD) 19.6 ± 7.3 19.7 ± 7.1
Education level
High school 3 (3.0%) 4 (4.1%)
Undergraduate 82 (82.0%) 69 (70.4%)
Graduate 15 (15.0%) 25 (25.5%)
SD, standard deviation.

The mean acculturation score for all subjects was 2.71 (standard deviation 0.62, range 1.05–3.90); 30 scored low (1 < x < 2), 92 scored moderate (2 ≤ x < 3), and 76 scored high (3 ≤ x < 4) on the acculturation scale, with no subjects belonging to the no acculturation or complete acculturation groups. The acculturation mean score by ethnicity was 2.63 for Chinese, 2.62 for Korean, 2.89 for Japanese, 3.15 for Filipino, 3.15 for other, and 2.48 for those not responding to this question. Statistical comparison was not possible due to the significant variation in sample size among the five subgroups. As anticipated, there was a strong direct relationship between the duration of residence in the USA and the level of acculturation ( R = 0.9484, P < 0.05; Table 3 ). There was a strong inverse relationship between age and the level of acculturation ( R = −0.9475, P < 0.05) indicating that the older the subject, the less acculturated. Male subjects were more likely to be acculturated than female subjects ( P < 0.05). Among the male subjects, the higher the education level, the less acculturated; no pattern was noted among female subjects.

Table 3
Descriptive statistics among the low, moderate, and high acculturation groups ( N = 198).
Low acculturation Moderate acculturation High acculturation Statistical significance
Number of subjects 30 (15.2%) 92 (46.5%) 76 (38.3%)
Age in years (mean ± SD) 28 ± 9.58 24.08 ± 4.30 23 ± 3.27 R value: −0.9475 *
Years in USA (mean ± SD) 9.04 ± 8.51 19.92 ± 5.69 22.82 ± 3.55 R value: 0.9484 *
Male 10 42 46 P < 0.05 *
Female 20 50 30 P > 0.05
SD, standard deviation.

* P < 0.05.

Class II male

For the class II male, the orthodontic camouflage simulation or flatter profile was considered less aesthetic for subjects with higher acculturation scores (OR 1.6, 95% CI 1.1–2.4, P < 0.012; Table 4 and Fig. 2 ). In addition, the higher acculturated subjects preferred mandibular advancement compared to the less acculturated individuals (OR 0.79, 95% CI 0.54–1.2, P = 0.219; Table 5 and Fig. 6 ). However, this latter finding was not statistically significant.

Table 4
Distribution of aesthetic ranking for class II male facial profile treated with orthodontic camouflage. Respondents with higher acculturation scores found orthodontic camouflage less attractive (OR 1.6, 95% CI 1.1–2.4, P = 0.012).
Low acculturation ( n = 30) Moderate acculturation ( n = 92) High acculturation ( n = 76)
Most aesthetic 66.7% 31.5% 31.6%
Moderately aesthetic 20% 32.6% 34.2%
Least aesthetic 13.3% 35.9% 34.2%
OR, odds ratio; CI, confidence interval.

Table 5
Distribution of aesthetic ranking for class II male facial profile treated with mandibular advancement. Higher acculturated subjects found mandibular advancement more aesthetic than less acculturated subjects (OR 0.79, 95% CI 0.54–1.2, P = 0.219).
Low acculturation ( n = 30) Moderate acculturation ( n = 92) High acculturation ( n = 76)
Most aesthetic 26.7% 41.3% 40.8%
Moderately aesthetic 20% 20.7% 21.0%
Least aesthetic 53.3% 38.0% 38.2%
OR, odds ratio; CI, confidence interval.

Fig. 6
Forest plot of the odds ratios of each treatment simulation for the different sagittal discrepancies (class II male, class II female, class III male, class III female). An odds ratio of <1 would indicate that more acculturated subjects had higher odds of selecting a particular profile as attractive compared to less acculturated subjects. An odds ratio of >1 would indicate that more acculturated subjects had higher odds of selecting a particular profile as unattractive compared to less acculturated subjects. In general, highly acculturated subjects preferred a fuller facial profile, while low acculturated subjects preferred a flatter facial profile appearance in post-treatment outcomes. One treatment preference that did not follow this pattern was the treatment for the class III female. It was found that highly acculturated subjects preferred a flatter profile with a mandibular setback. The asterisk (*) indicates P < 0.05.

Class II female

For the class II female with orthodontic camouflage, higher acculturated subjects found this profile less aesthetic, although this was not statistically significant (OR 1.3, 95% CI 0.88–1.94, P = 0.191; Table 6 and Fig. 3 ). For the class II female treated with mandibular advancement, higher acculturated subjects found this movement more aesthetic than less acculturated subjects and this was statistically significant (OR 0.5, 95% CI 0.34–0.73, P = 0.004; Table 7 and Fig. 6 ).

Table 6
Distribution of aesthetic ranking for class II female profile treated with orthodontic camouflage. Higher acculturated subjects found this profile less aesthetic compared to less acculturated subjects (OR 1.3, 95% CI 0.88–1.94, P = 0.191).
Low acculturation ( n = 30) Moderate acculturation q( n = 92) High acculturation ( n = 76)
Most aesthetic 56.7% 57.6% 50%
Moderately aesthetic 43.3% 38.0% 38.2%
Least aesthetic 0% 4.4% 11.8%
OR, odds ratio; CI, confidence interval.

Dec 15, 2017 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Acculturation levels and personalizing orthognathic surgery for the Asian American patient
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