07 September 2022

---

Evaluation of the mandible / condylar position through a completely virtual approach

Lara Figini

---

In the dental field, especially in the implant-prosthetic and orthodontic sector, identifying the exact occlusion of the patient is important for a correct and successful treatment planning and to avoid the appearance of noises and joint pains, which can indicate pathology. When there is an occlusal discrepancy between the position of maximum intercuspidation (MIP) and the position of centric relationship (CR) it is called unstable occlusion and the condylar position must be carefully evaluated.

For this reason, the static and dynamic positions of the mandible must be precisely determined and the classic methodology is the one based on the use of the face bow and an articulator to detect and record joint and occlusal data, procedures that are not always easy and immediate. With the advent of digital technology, these procedures can be simplified with a virtual face bow and mounting on a virtual articulator.

Materials and methods
In an article published in the Journal of Prosthetic Dentistry of June 2021, the authors described a completely digital technique to assess the mandibo / condylar position for both occlusion in centric relation (CRO) and that in the position of maximum intercuspidation (MIP). The method was conducted on a 25-year-old woman who reported joint noises occasionally. The above procedure transfers maxillary and mandibular position data to a virtual articulator based on images obtained with single cone beam computed tomography (CBCT). A CBCT scan of the patient was obtained in CRO and the maxilla and mandibular models were scanned in both CRO and MIP with an intraoral scanner. The scan data of the CRO model was recorded on the dental part of the CBCT image using a program that simulated a virtual articulator and a process of transfer and assembly of the virtual face bow was performed. The virtual articulator was positioned in the mesial pole of the right and left condyle and in the right orbital. Mandibular position was assessed in CRO and MIP by superimposing the mandible data in position in both CRO and MIP. A quantitative 3D measurement was obtained.

Results and conclusions
Based on this protocol, a fully digital approach can be used to transfer a patient's mandibular / condylar position to a virtual articulator based on data from a single scan with CBCT and intraoral scans.

Clinical implications
This technique can eliminate the traditional facial bow joint data transfer procedure, the subsequent assembly process, and the complicated laboratory procedures for assessing mandibular position in CRO and MIP.

For additional information: A digital approach to the evaluation of mandibular position by using a virtual articulator