Oral health-related quality of life between Chinese and American orthodontic patients: A two-center cross-sectional study

Background: Although oral health-related quality of life (OHRQoL) in orthodontic patients has been assessed in the past, to date, no study has compared the OHRQoL between two nations. We aimed to compare the OHRQoL between Chinese and American orthodontic patients. Methods: We conducted a two-center questionnaire-based cross-sectional study among patients who underwent orthodontic treatments at the Chinese PLA General Hospital (PLAGH) in Beijing, China and Massachusetts General Hospital (MGH) in Boston, Massachusetts, United States. Candidate variables included the participating center, patients’' age, sex, Angle’s classification of malocclusion, evaluation stage, and appliances used. The primary outcome was patients’ OHRQoL assessed with the Oral Health Impact Profile-14 (OHIP-14). Descriptive statistics, stratification, and univariate and multivariate analyses were performed. Results: The average age was lower for PLAGH patients than for MGH patients (21.1 ​± ​7.9 vs. 33.1 ​± ​14.6 years, P<0.001). The most common type of malocclusion was Angle’s Class III malocclusion at PLAGH (39%) and Class I malocclusion at MGH (59.5%). Clear aligners were used in 34.1% and 2.7% of the patients at MGH and PLAGH, respectively. OHIP-14 scores were lower for PLAGH patients than for MGH patients (18.4 ​± ​4.7 vs. 22.3 ​± ​7.4, P<0.001), particularly in functional limitation, psychological discomfort/disability, and handicap. Univariate regression analysis demonstrated that participating center, age, Class I malocclusion, and the use of clear aligners were significantly associated with overall OHIP-14 scores. Multivariate regression analysis demonstrated that patients at PLAGH were associated with lower OHIP-14 scores (coefficient: −3; 95% CI: −5, −1.3; P=0.001), and age was positively associated with OHIP-14 scores (coefficient: 0.1; 95% CI: 0.004, 0.13; P=0.038). Conclusion: Chinese orthodontic patients had lower OHIP-14 scores, indicating a higher OHRQoL than American patients. In addition to the younger age, this difference may be attributed to the different ethical, cultural, educational, and socioeconomic background of Chinese and American orthodontic patients.