**Core Concept**
Occlusal night guards are custom-made oral appliances used to prevent or treat various dental and orofacial disorders. They are designed to alter the occlusal relationship between the upper and lower teeth, thereby modifying the bite and reducing the forces exerted on the teeth and surrounding tissues.

**Why the Correct Answer is Right**
Occlusal night guards are commonly used to prevent or manage bruxism, a condition characterized by habitual grinding or clenching of the teeth, often during sleep. By absorbing the forces generated by these movements, occlusal night guards help to reduce the risk of tooth wear, temporomandibular joint (TMJ) disorders, and other orofacial pain conditions. The use of occlusal night guards can also be beneficial in managing sleep disorders such as sleep bruxism, which is often associated with other conditions like sleep apnea.

**Why Each Wrong Option is Incorrect**
* **Option A:** Occlusal night guards are not typically used to treat orthodontic issues, as they do not provide the same level of precision and control as orthodontic appliances.
* **Option B:** While occlusal night guards may have some benefits for TMJ disorders, they are not a primary treatment for conditions like TMJ arthritis or disc displacement.
* **Option C:** Occlusal night guards are not used to treat sleep apnea, although they may be used in conjunction with other treatments to help manage associated bruxism.

**Clinical Pearl / High-Yield Fact**
A key consideration when prescribing occlusal night guards is the importance of proper fit and customization to the individual's dental anatomy. A poorly fitting guard can exacerbate orofacial pain and discomfort, rather than providing relief.

**Correct Answer:** D