Use of a properly fitting mouth guard while playing sports helps to protect against all the following conditions EXCEPT one. Which is the EXCEPTION?

The use of a properly fitting mouth guard is primarily aimed at protecting the teeth, gums, and jaw from injury during sports activities. It effectively absorbs and distributes the forces of impact to minimize the risk of dental trauma, including broken or knocked-out teeth, and also protects the soft tissues of the mouth.

When considering the role of a mouth guard, it is important to note that it does not address mouth breathing. Mouth breathing often occurs due to nasal obstructions or other respiratory issues rather than direct injury or impact. While a mouth guard may slightly alter airflow, it does not prevent the underlying causes of mouth breathing.

In contrast, a mouth guard can help mitigate bruxism (the grinding of teeth) and clenching, both of which can occur during high-stress sports situations. Additionally, while it cannot prevent all head injuries, a mouth guard does provide some level of protection against concussions by cushioning blows to the jaw and reducing transmission of forces to the brain.

Therefore, the correct answer highlights that mouth breathing is not a protected condition by the use of a mouth guard, as its purpose is primarily dental protection and does not directly influence breathing patterns.