Effect of non-working occlusal contacts on vertical condyle position

Area of Science:

• Dental Occlusion
• Temporomandibular Joint (TMJ) Biomechanics

Background:

• Non-working occlusal contacts are frequently perceived as detrimental to temporomandibular joint (TMJ) health.
• Understanding the precise biomechanical effects of these contacts is crucial for dental diagnostics and treatment planning.

Purpose of the Study:

• To investigate the influence of non-working occlusal contacts on the condylar position during varying levels of jaw clenching.
• To determine if artificial non-working contacts can alter condylar movement patterns.

Main Methods:

• Twenty-two healthy subjects with canine-guided occlusion participated.
• Condylar position (vertical and horizontal) was tracked using a six-degrees-of-freedom ultrasonic motion analyzer during clenching.
• Subjects performed clenching on the canine alone and with artificial non-working side contacts (bite registration material).

Main Results:

• Clenching solely on the canine resulted in cranial (upward) movement of the non-working side condyle.
• The presence of artificial non-working occlusal contacts significantly reduced this cranial condylar movement by 0.6-0.9 mm.
• Surface electromyography of the masseter muscle controlled for consistent clenching intensity.

Conclusions:

• Non-working occlusal contacts appear to play a protective role by limiting excessive upward (cranial) displacement of the TMJ condyle.
• These findings suggest that the presence or absence of non-working contacts can significantly impact TMJ biomechanics during function.