Definition of Occlusal Plane Based on Hard Tissue of Craniofacial

Objectives: Defining a proper occlusal plane is crucial for phonetics, mastication, and aesthetics of a dental prosthesis. While the existing methods determine the occlusal plane using soft tissue landmarks on the cephalometric film, complete information of soft tissue is often not acquired from the CBCT scans for routine dental examination. Therefore, this study aims to develop a method to define the occlusal plane based on hard tissue landmarks.
Methods: Thirty-three patients, three with teeth and thirty without, underwent cephalometric analysis to identify anterior nasal spine, posterior nasal spine, gonion (both sides), menton, supramentale and subspinale of the jaw bones. These seven landmarks were used to calculate the intersection point of the mandibular plane and the line connecting the anterior and posterior nasal spines. Then the occlusal plane was derived by rotating the mandibular plane about an axis perpendicular to the sagittal plane at the intersection point.
Results: In the edentulous patients, the average angular difference between the occlusal plane and the natural occlusal plane was only 1.95 degrees, and the occlusal planes of the edentulous patients were similar to those determined by the dentist.
Conclusions: The proposed method accurately locates the occlusal plane without requiring the presence of complete information of soft tissue, making a substantial amount of existing CBCT scans possible to acquire occlusal planes . The method has also been evaluated by clinicians to provide accurate occlusal plane decisions for full mouth rehabilitation.