While vocal cords are the primary component in creating your voice & its individual timbre, your mouth plays a role in shaping it too. Your voice can even change after dental work or as your jaw muscles become stressed. This can be especially noticed while singing, when voices are stretched to their limits.
Palatable Proportions
The shape of your mouth has a lot to say about your singing voice. In a 2019 PubMed study, singers were recorded & measurements were taken of the inner dimensions of their mouth. Their recordings were also measured for vocal strength & pitch range.
The study showed that those whose mouths had a larger frontal area were suited for the style opera singers use, while those with larger mouths overall projected more powerfully. The study referred to the latter as “belting style” singing.
Tuned Teeth
Your teeth, & how they are aligned, can also impact your voice. Hard objects like teeth tend to resonate with certain frequencies. Vocal resonance can be thought of as the quality & intensity of your voice’s tone. While teeth play a minimal role in shaping your projected voice, sound waves will still alter slightly in both frequency & direction as they bounce off your teeth. Changing the alignment or shape of your teeth can change your voice, but this is only noticeable in singing or other extreme vocalizations that push a person’s expressive limits.
More often, teeth shape our voice through the spaces between them, causing whistles or lisps in certain cases. There are a range of orthodontic solutions like metal braces or clear aligners that can aid in reducing or eliminating these effects if desired.
Muscular Mandibles
As with other muscles in your body, the muscles in your mouth & throat work best when they are properly conditioned & well-rested. Over-exertion of your mandible can lead to poorer singing as it becomes difficult—even painful—to open your mouth wide enough or articulate properly.
Bruxism is a main culprit of stress on your jaw’s temporomandibular joint—or TMJ. Bruxism is a chronic clenching or grinding of teeth that wears on teeth & muscle alike. While its exact causes are unknown, bruxism is most prevalent during sleep. Waking bruxism can be reduced with mental queues that help you realize you are grinding your teeth, while night guards can ease the pressure while you sleep.
Your dentist can have a custom-made night guard made for you, & even if you don’t realize you suffer from bruxism, your dentist is trained to spot signs you may have missed. So be sure to bring up any jaw or throat pain at your next visit.
Sources:
https://www.csmusic.net/content/articles/the-dr-is-in-your-jaw-and-your-voice/
https://pubmed.ncbi.nlm.nih.gov/31676168/
https://www.teenstarcompetition.co.uk/advice/do-wisdom-teeth-affect-singing/
https://en.wikipedia.org/wiki/Vocal_resonation