Introduction An occlusal appliance, also known as a bite guard or bite splint, is a dental device used for various therapeutic and preventive purposes. It is made of hard or soft acrylic material and is custom-fabricated according to the patient’s measurements. The appliance is designed to fit over the occlusal surfaces and incisal surfaces of the maxillary teeth or mandibular teeth. Uses of Occlusal Appliances Occlusal appliances have several important applications in dentistry, particularly in the treatment and management of Temporomandibular Disorders (TMD). In patients experiencing these disorders, the appliance helps establish a more functionally and mechanically stable position of the Temporomandibular Joint (TMJ). It also contributes to the reorganization of neuromuscular reflex activity. In addition to providing relief from pain symptoms, the use of an occlusal appliance may also assist in confirming the diagnosis of TMD through the observation of symptom improvement following its use. Role of Occlusal Appliances in the Prevention of Tooth Wear Occlusal appliances are commonly used to prevent tooth wear resulting from bruxism, which occurs due to involuntary clenching or grinding of the teeth. The appliance acts as a protective barrier between the teeth, reducing the effects of pressure and friction caused by bruxism and helping protect the dental structures from wear and damage. Use of Occlusal Appliances in Prosthodontic Rehabilitation Dentists may use an occlusal appliance to evaluate the patient’s tolerance to an increase in the Vertical Dimension of Occlusion (VDO) before performing Prosthodontic Rehabilitation. This procedure is important before the placement of dental restorations, such as crowns and bridges, as it helps assess the patient’s response to the proposed changes in the occlusal relationship between the jaws. Advantages of Occlusal Appliance Therapy Reversibility and the noninvasive nature of treatment are among the most important advantages of occlusal appliance therapy. However, this treatment requires patient cooperation and compliance with wearing the appliance according to the dentist’s instructions, as its therapeutic effectiveness depends on regular and proper use. Occlusal Appliance Adjustment and Treatment Follow-up To achieve maximum benefit from treatment, the dentist must carefully adjust the occlusal appliance at the time of delivery and perform the necessary modifications periodically thereafter. These adjustments aim to ensure proper appliance fit, establish correct occlusal contacts, maintain continued therapeutic effectiveness, and reduce the possibility of problems resulting from improper use. Conclusion The occlusal appliance represents an important therapeutic and preventive approach in dentistry. It contributes to the relief of symptoms associated with temporomandibular disorders, the prevention of tooth wear caused by bruxism, and the evaluation of changes in the vertical dimension of occlusion before prosthodontic rehabilitation. Due to its noninvasive nature and reversibility, it is considered a useful treatment option when used under the supervision of a dentist, with adherence to treatment instructions and regular follow-up to ensure the best possible outcomes. Al Mustaqbal University The First University in Iraq