Assessing inter- and intra-examiner reliability of orthodontists in devising incisor position objectives on cephalograms: a comparative study between senior and junior practitioners

BACKGROUND: Effective orthodontic treatment planning hinges on accurately defining incisor position objectives (IPO) in cephalograms. The purpose of this study was to estimate the inter-examiner and intra-examiner reliability of different orthodontists in devising IPOs on cephalograms. METHODS: Ten orthodontists, who were divided into to the senior group (N = 5) and the junior group (N = 5) based on their clinical experience, formulated IPOs for 60 pre-treatment cephalograms twice with an interval of 2 weeks, utilizing SmartOrtho software. The type and magnitude of movement were read directly in the software. A paired t-test assessed the absolute differences between the first and second IPO devising within each group and between the senior and junior groups in each time’s IPO devising. The intra-examiner and inter-examiner reliabilities were calculated. RESULTS: There were significant differences in all types of upper incisor movement and lower incisor protrusion/retraction movement between the first and second IPO devising of the senior group. The junior group exhibited significant differences in the twice the upper incisor extrusion/intrusion movement and upper incisor torque movement devising. Additionally, significant differences in all types of incisor movement between the senior and junior groups in each time’s IPO devising. Intra-examiner reliabilities were excellent for both two groups and moderate for the junior group in most types of incisor movement, respectively. The inter-examiner reliability between the two groups ranged from moderate to good across different types of incisor movement. CONCLUSIONS: Among orthodontists, both senior and junior practitioners displayed the best inter-examiner reliability in lower incisor extrusion/intrusion movement. In terms of intra-examiner reliability, senior orthodontists had better intra-examiner reliability in upper incisor position objectives devising than the junior orthodontists. Furthermore, senior orthodontists tended to adopt a more recessive, intrusive, and lingually torqued incisor position approach compared to junior orthodontists.