A three-dimensional morphometric study on the position of temporomandibular joints

Area of Science:

• Dental Anatomy
• Biomechanical Engineering
• Craniomaxillofacial Imaging

Background:

• The optimal use of average values versus individual registrations in dental articulation remains debated.
• Quantifying anatomical landmark variability is crucial for advancing articulation system accuracy.
• Understanding the natural bandwidth of temporomandibular joint (TMJ) positions is essential for prosthetic and orthodontic applications.

Purpose of the Study:

• To quantify the mean and natural bandwidth of parameters describing dental articulation.
• To provide data addressing the controversy surrounding average value articulation versus individual facebow registrations.
• To establish anatomical bandwidths for use in dental articulation systems.

Main Methods:

• Three-dimensional (3D) cone beam computed tomography (CBCT) scans of 120 individuals were analyzed.
• Key anatomical landmarks relevant to articulation were measured.
• Mean values and bandwidths of anatomical relations, including the Bonwill triangle and Balkwill angle, were calculated.

Main Results:

• The Bonwill triangle exhibited mean arm length of 103.3 mm and base length of 99.6 mm, with significant ranges.
• A high correlation was found between the left and right arm lengths of the Bonwill triangle.
• The mean Balkwill angle was 20.4 degrees (range: 9.0–27.6 degrees), and the angle between Camper's line and the occlusal plane averaged 7 degrees.

Conclusions:

• This study establishes the anatomical bandwidth for parameters essential in dental articulation systems, with results specific to sex.
• The findings indicate high symmetry between right and left sides for relevant anatomical parameters.
• The data supports the use of virtual articulators and potentially reduces reliance on facebows by providing normative anatomical data.