Quantitative analysis of the mouth opening movement of temporomandibular joint disorder patients according to disc position using computer vision: A pilot study

Kug Jin Jeon, Young Hyun Kim, Eun Gyu Ha, Han Seung Choi, Hyung Joon Ahn, Jeong Ryong Lee, Dosik Hwang, Sang Sun Han

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Background: Temporomandibular joint disorder (TMD), which is a broad category encompassing disc displacement, is a common condition with an increasing prevalence. This study aimed to develop an automated movement tracing algorithm for mouth opening and closing videos, and to quantitatively analyze the relationship between the results obtained using this developed system and disc position on magnetic resonance imaging (MRI). Methods: Mouth opening and closing videos were obtained with a digital camera from 91 subjects, who underwent MRI. Before video acquisition, an 8.0-mm-diameter circular sticker was attached to the center of the subject's upper and lower lips. The automated mouth opening tracing system based on computer vision was developed in two parts: (I) automated landmark detection of the upper and lower lips in acquired videos, and (II) graphical presentation of the tracing results for detected landmarks and an automatically calculated graph height (mouth opening length) and width (sideways values). The graph paths were divided into three types: Straight, sideways-skewed, and limited-straight line graphs. All traced results were evaluated according to disc position groups determined using MRI. Graph height and width were compared between groups using analysis of variance (SPSS version 25.0; IBM Corp., Armonk, NY, USA). Results: Subjects with a normal disc position predominantly (85.72%) showed straight line graphs. The other two types (sideways-skewed or limited-straight line graphs) were found in 85.0% and 89.47% in the anterior disc displacement with reduction group and in the anterior disc displacement without reduction group, respectively, reflecting a statistically significant correlation (χ2=38.113, P<0.001). A statistically significant difference in graph height was found between the normal group and the anterior disc displacement without reduction group, 44.90±9.61 and 35.78±10.24 mm, respectively (P<0.05). Conclusions: The developed mouth opening tracing system was reliable. It presented objective and quantitative information about different trajectories from those associated with a normal disc position in mouth opening and closing movements. This system will be helpful to clinicians when it is difficult to obtain information through MRI.

Original languageEnglish
Pages (from-to)1909-1918
Number of pages10
JournalQuantitative Imaging in Medicine and Surgery
Issue number3
Publication statusPublished - 2022 Mar

Bibliographical note

Funding Information:
Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (2019R1A2C1007508).

Funding Information:
Funding: This work was supported by a National Research

Publisher Copyright:
© 2022 AME Publishing Company. All rights reserved.

All Science Journal Classification (ASJC) codes

  • Radiology Nuclear Medicine and imaging


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