Intra-rater and Inter-rater Reliability of Mandibular Range of Motion Measures Considering a Neutral Craniocervical Position

[Purpose] The aim of this study was to determine the inter-rater and intra-rater reliability of the mandibular range of motion (ROM) considering the neutral craniocervical position when performing the measurements. [Subjects and Methods] The sample consisted of 50 asymptomatic subjects. Two raters measured four mandibular ROMs (maximal mouth opening (MMO), laterals, and protrusion) using the craniomandibular scale. Subjects alternated between raters, receiving two complete trials per day, two days apart. Intra- and inter-rater reliability was determined using intra-class correlation coefficients (ICCs). Bland-Altman analysis was used to assess reliability, bias, and variability. Finally, the standard error of measurement (SEM) and minimal detectable change (MDC) were analyzed to measure responsiveness. [Results] Reliability was good for MMO (inter-rater, ICC= 0.95-0.96; intra-rater, ICC= 0.95-0.96) and for protrusion (inter-rater, ICC= 0.92-0.94; intra-rater, ICC= 0.93-0.96). Reliability was moderate for lateral excursions. The MMO and protrusion SEM ranged from 0.74 to 0.82 mm and from 0.29 to 0.49 mm, while the MDCs ranged from 1.73 to 1.91 mm and from 0.69 to 0.14 mm respectively. The analysis showed no random or systematic error, suggesting that effect learning did not affect reliability. [Conclusion] A standardized protocol for assessment of mandibular ROM in a neutral craniocervical position obtained good inter- and intra-rater reliability for MMO and protrusion and moderate inter- and intra-rater reliability for lateral excursions.