Stability of mandibular position in continuous vowel phonation

Area of Science:

• Dentistry
• Biomechanics
• Speech Science

Background:

• Accurate determination of occlusal vertical dimension (OVD) is crucial in restorative dentistry.
• Understanding mandibular dynamics during speech is essential for functional occlusion assessment.

Purpose of the Study:

• To evaluate the stability of mandibular positions during sustained phonation of different vowels.
• To assess the relationship between vowel phonation positions and the natural rest position of the mandible.
• To determine the viability of using specific vowel phonations for OVD measurement.

Main Methods:

• Thirty adult males with natural dentition were recruited.
• A mandibular kinesiograph was used to record mandibular movements during continuous phonation of vowels [a], [e], [i], [o], [u].
• Data were analyzed to assess positional stability and relation to the rest position.

Main Results:

• The mandibular position during continuous phonation of the vowel [i] demonstrated significant stability.
• This stable [i] phonation position showed a close correlation with the mandibular rest position.
• Other tested vowels ([a], [e], [o], [u]) exhibited less stable mandibular positions.

Conclusions:

• Continuous phonation of the vowel [i] offers a stable and reproducible mandibular position.
• The close relationship between [i] phonation position and rest position supports its clinical utility.
• Sustained [i] phonation is proposed as a practical method for determining occlusal vertical dimension in dental practice.