RELIABILITY OF MEASURING ACTIVE MANDIBULAR EXCURSION USING A NEW TOOL- THE MANDIBULAR EXCURSIOMETER

Measurement tools improve the reliability and validity of measurement. The purpose of this study was to test the intrarater and interrater r eliability of a new instrument, the Mandibular Excursiometer, for meas uring mandibular excursion on the X and Y axis in the coronal plane du ring active opening. Two raters measured 12 volunteers. Four ratio, th ree nominal, and one ordinal scale measurements were analyzed using pe rcent agreement. The Mandibular Excursiometer had high intrarater reli ability for vertical opening (100%) and for the categorization oi the presence or absence and direction oi lateral deviation at the maximum point during opening (92-100%). Overall, moderate intrarater reliabili ty existed for the quantity of lateral deviation al the maximum point during opening (66-83%), presence and direction of deflection (66-83%) , presence of deviation or deflection during opening (66-83%) and in w hich third of opening the maximum point of lateral deviation occurred (66-83%). Moderate interrater reliability existed for vertical opening (75%) and for the classification of presence and direction of lateral deviation at the maximum point during opening (91%). All other measur ements had low reliability. The Mandibular Excursiometer had higher in trarater and interrater reliability for measuring deviation and deflec tion during active mandibular opening than observation alone, based on a comparison with the literature. This measurement can assist in docu menting progress while treating patients with TMJ disorders.