Acute Effects on Masticatory Muscle Activity and Swallowing Following Increases in Occlusal Vertical Dimension Using...

Area of Science:

• Oral physiology
• Biomechanics of mastication
• Neuromuscular control of swallowing

Background:

• Occlusal vertical dimension (OVD) is a critical parameter in prosthodontics and dental rehabilitation.
• Understanding the acute effects of OVD changes on oral motor function is essential for patient safety and treatment outcomes.
• Previous research has not fully elucidated the immediate neuromuscular responses to short-term OVD increases during swallowing.

Purpose of the Study:

• To investigate the acute impact of incremental increases in OVD on tongue pressure and jaw muscle electromyographic (EMG) activity during swallowing.
• To assess potential neuromuscular adaptations or disturbances associated with short-term OVD alterations.

Main Methods:

• A pilot study involving 22 healthy adults.
• Swallowing was evaluated at baseline OVD and with 2, 4, and 6 mm increases using wax occlusal stops.
• Measurements included tongue pressure (Flexiforce sensor) and masseter/temporalis muscle EMG activity.
• Data analyzed using linear regression with a significance level of p < 0.05.

Main Results:

• No significant acute changes in masseter or temporalis muscle EMG activity were observed across different OVD levels during saliva swallowing (SS).
• Tongue pressure showed significant increases at 4 mm and 6 mm OVD during SS compared to baseline.
• Tongue pressure significantly increased across all tested OVD increments during yogurt swallowing (YS).

Conclusions:

• Short-term increases in OVD up to 6 mm did not induce significant acute changes in jaw muscle EMG activity.
• Minor adaptive variations in tongue pressure were noted with increased OVD, particularly during swallowing of thicker substances (YS).
• The study found no immediate neuromuscular disturbances, but the pilot nature precludes long-term safety conclusions.