Determining Intercondylar Distance Using Cone-beam Computed Tomography (CBCT)

Abstract

Purpose: To measure the intercondylar distance (ICD) from cone-beam computed tomography (CBCT) scans of a large population of subjects to determine the average ICD in male and female subject and to correlate ICD measurement obtained with sex and ethnicity of the subjects. Materials and Methods: This cross-sectional study analyzed consecutive patients who had received maxillofacial field of view CBCT radiographic examinations at the University of Maryland School of Dentistry (UMSOD) between January 20th, 2016, and July 5th, 2023. Inclusion criteria comprised individuals over 18 years old who had maxillofacial CBCT scans on file in the UMSOD INFINITT (INFINITT NA, Phillipsburg, NJ) PACS system. Exclusion criteria included patients with prosthetic condyles, bone growth-affecting diseases, incomplete scans, poor image quality, or missing sex and age information. Of the initially included 459 patients, 25 were excluded. Data collected from patient charts included age, sex, presence of bone growth-affecting diseases, and measurements of left and right condyles, as well as ICD. The primary investigator reviewed scans, conducted chart reviews, and made measurements on the 434 included files. Results: Four hundred and thirty-four images of subjects were analyzed. The sample consisted of an even number of male and female subjects (217). The median ICD value was 102.9 mm (min 86.2 mm – max 118.2 mm) for male subjects and 98.4 mm (min 81.5 – max 117.2) mm for female subjects. The mean ICD value of male and female subjects combined (total 434 subjects) was 100.92 mm (min 81.5 mm – max 118.2 mm) and the median value was 100.5 mm. There was statistically significant difference between ICD values of male and female subjects (P<0.0001), but not between Caucasian and African American subjects (P=0.69). There was no significant difference in the interaction between sex and ethnicity (P=0.84). Conclusions: The ICD influences the radius of movement and the arcs traveled by the cusps during lateral mandibular movements in the horizontal plane. Although canine disocclusion can mitigate inaccuracies arising from an average ICD, it may not fully compensate for individual variations in all patients. For patients restored with group function occlusion, ICD setting may be more critical. Articulators with an adjustable ICD would provide a more anatomically correct tooth form for the treatment of full mouth rehabilitation cases.