Effect of Measurement Technique on TMJ Mandibular Condyle and Articular Disc Morphometry: CBCT, MRI and Physical Measurements

Publication date: Available online 10 July 2018

Source: Journal of Oral and Maxillofacial Surgery

Author(s): Matthew C. Coombs, Daniel J. Bonthius, Xingju Nie, Michael K. Lecholop, Martin B. Steed, Hai Yao

Abstract

Purpose

Accurate description of temporomandibular size and shape (morphometry) is critical for clinical diagnosis and surgical planning, design and development of regenerative scaffolds and prosthetic devices, and to model the temporomandibular loading environment. The study objective was to determine the three-dimensional morphometry of the temporomandibular joint (TMJ) condyle and articular disc by CBCT, MRI and physical measurements on the same joints using a repeated measures design, to determine the effect of measurement technique on temporomandibular size and shape.

Materials and Methods

Human cadaveric heads underwent a multi-step protocol, acquiring physiologically meaningful measurements of the condyle and disc. Heads first underwent CBCT scanning and solid models were automatically generated. Superficial soft tissues were dissected and intact TMJs were excised and underwent MRI scanning, and solid models were generated following manual segmentation. Following MRI scanning, intact joints were dissected and physical measurements of the condyle and articular disc were made. CBCT-based model measurements, MRI-based model measurements and physical measurements were standardized, and a repeated measures study design determined the effect of measurement technique on morphometric parameters.

Results

Multivariate general linear mixed effects models showed significant effects for measurement technique for condylar morphometric outcomes (p<0.001) and articular disc morphometric outcomes (p<0.001). Physical measurements following dissection were larger than both CBCT-based and MRI-based measurements. Differences in imaging-based morphometric parameters followed a complex relationship between imaging modality resolution and contrast between tissue types.

Conclusion

Physical measurements following dissection are still considered the gold standard, however due to their inaccessibility in vivo, understanding how imaging technique impacts temporomandibular size and shape is critical towards the development of high-fidelity solid models, to be utilized in the design and development of regenerative scaffolds, surgical planning, prosthetic devices and for anatomical investigations.

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