Reliability of a digital image method for measuring medial mandibular flexure in dentate subjects.
Medial mandibular flexure (MMF) is the functional approximation of hemi-mandibles in jaw opening and protrusion, which may affect conventional or implant-supported arch prostheses.


OBJECTIVE
This study evaluated the intra- and inter-rater reliability of a digital image method for linear measurement of MMF in dentate subjects.


METHODS
Mandibular occlusal impressions in vinyl polysiloxane during rest and maximum opening were obtained from seven adult volunteers. Each impression and the Mitutoyo digital calipers with a 10mm opening were scanned at a 200% magnification. The images were processed using Adobe Photoshop software to get reference points on contralateral first molars. Linear intermolar measurements were taken using the Image Tool software (UTHSCSA), which was calibrated with the standard opening of the digital calipers. Intermolar distance was measured in triplicate for each image by two independent examiners. MMF was calculated by subtracting the intermolar distance in maximum opening (or protrusion) from the distance in rest position. Data were analyzed by intraclass correlation (ICC) tests for estimating intra- and inter-rater reliability.


RESULTS
MMF values ranged from -0.21 to 0.44mm. Intra-rater ICCs were 0.982 and 0.993, and inter-rater ICC was 0.696.


CONCLUSIONS
The present results show excellent intra-rater and good inter-rater reliability of this digital image method for measuring MMF in dentate subjects.
Department of Prosthodontics, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil.
Rosemary Sadami Arai
RS
Shinkai
Simone de Andrade
Sde A
Canabarro
Caroline Bom
CB
Schmidt
Evandro Afonso
EA
Sartori