Three-dimensional visualization of temporomandibular joint after occlusal changes using facial scanning techniques combined with single cone beam computed tomography.

Objective: Current cone beam computed tomography (CBCT) methods cannot demonstrate the temporomandibular joint fossa-condyle relationship in real time. This study aimed to print a simple guide plate with marker points and capture a single CBCT scan based on positional changes of the marker points to align the maxilla and mandible positions.

Methods: The three groups were divided into the intercuspal position, 5 mm unilateral elevation, and 10 mm bilateral elevation to simulate different patient occlusal situations after treatment. The maxillary and mandibular positions were aligned according to points marked on the reference plate. Then, the deviation was compared between the three-dimensional images obtained employing this method and those reconstructed from CBCT. A one-way analysis of variance was conducted, and post hoc analyses were performed using the Tamhane's T2 multiple comparison test (α = 0.05).

Results: The intercuspal position had a mean deviation value of - 0.1313 with an RMS of 0.4411. The unilateral elevation had a mean deviation value of 0.3253 with an RMS of 1.2707. The bilateral elevation had a mean deviation value of - 0.0537 with an RMS of 1.281. There were no statistical differences among the three groups at α = 0.05.

Conclusion: This method can reduce the number of CBCT scans to one and predict the relative positions of the maxilla and mandible when changes in joint position occur from occlusion. This method can increase the accuracy of treatment, assist novice doctors to adjust the occlusal height, provide a visual means to extract and verify the treatment effect, reduce the number of diagnoses and treatments to a certain extent, reduce the radiation damage during treatment, and can be better applied to the chair side, providing convenience for patients and doctors.

Clinical significance: The method described in this study used a face scan, reference plate, and the first CBCT of the participant combined with 3D reconstruction to clinically observe the temporomandibular joint. This method can reduce the number of CBCT scans required, amount of radiation exposure, patient burden, and number of clinic visits while increasing the comfort level of patients.