Reliability of mandibular range of motion measurements in healthy children

Background: Mandibular range of motion (MROM) variables are widely used to evaluate oral function. Objective: The aim of this study was to establish the reliability of MROM variables in healthy children. Methods: In this cross-sectional study, healthy children were examined 2 weeks apart. The following MROM variables were established: active maximum interincisal opening (AMIO), passive maximum interincisal opening (PMIO), protrusion and left and right laterotrusion. The reliability of the MROM measurements was determined by analysing the intra-class correlation coefficient (ICC), standard error of measurement (SEM), smallest detectable change (SDC) and limits of agreement (LoA). Results: A total of 167 healthy children were examined. The ICC indicated good reliability for AMIO (0.885); excellent reliability for PMIO (0.925); and moderate reliability for protrusion (0.578), laterotrusion left (0.601) and laterotrusion right (0.634). The SDC was 0.9 mm for AMIO, 0.4 mm for PMIO, 2.2 mm for protrusion, 1.6 mm for laterotrusion left and 1.4 mm for laterotrusion right. The LoA was −5.67 to 5.82 for AMIO, −3.90 to 3.57 for PMIO, −3.89 to 3.55 for protrusion, −2.99 to 2.77 for laterotrusion left, and − 2.71 to 2.77 for laterotrusion right. Conclusions: AMIO and PMIO measurements are both highly reliable in healthy children. The low SDC indicate that AMIO and PMIO are promising longitudinal measurements. Protrusion and laterotrusion measurements had moderate reliability. These results support our clinical recommendation to measure AMIO rather than PMIO, as PMIO is more difficult and more time-consuming to perform than AMIO.