Factors Affecting Patient Treatment Duration in an Advanced Orthodontic Education Clinic

This study investigated the effect of multiple patient and treatment-related factors, together with supervision frequency of assigned attending faculty, on orthodontic treatment duration in an advanced education clinic.

This study included 295 patients who completed non-surgical orthodontic treatment at the Ohio State University graduate orthodontic clinic during 2016-2020, whose active treatment duration was calculated. Fifteen factors, including patients' age, sex, Medicaid eligibility, number of broken and urgent appointments, initial and final Peer Assessment Rating (PAR) Index, PAR improvement, occurrence of transfers, extraction or non-extraction plan, midcourse treatment plan change, extended adjustment interval, and frequency of assigned faculty supervision, were collected. Intra-rater reliability of data acquisition was assessed by intraclass correlation coefficient (ICC) and kappa tests for continuous and categorical variables, respectively. Effects of these factors on treatment duration were assessed by an Analysis of Covariance (ANCOVA) test.

Intra-rater reliability for data acquisition was excellent (ICC or kappa > 0.9) except for treatment plan change. For effects on treatment duration, statistical significance (p < 0.05) was reached for the number of broken and urgent appointments, initial PAR score, supervision frequency of assigned faculty, occurrence of transfer among residents, and major treatment plan change. As for clinical significance (reflected by estimates of impact), an increase in the number of broken/urgent appointments and the occurrence of transfer prolonged treatment duration more substantially than a decrease in faculty supervision frequency.

To avoid prolonging treatment duration in graduate orthodontic clinics, efforts to reduce patients' broken/urgent appointments and transfers among residents are more important than maximizing assigned faculty supervision frequency.