Occlusal splints are employed in the treatment of sleep bruxism. These appliances decrease sleep-related actions and damages bruxism, like grinding, tooth-wear, headache, and temporomandibular joint disorders. Occlusal splints are produced both in hard and soft forms according to the used material.

In this study, it was aimed to evaluate the effect of occlusal splint type on the sleep quality and occlusal force parameters of patients with sleep bruxism.

Various splint designs have been used for the treatment of sleep bruxism that is made up of different materials: Hard and soft splints. Although, these splints have slightly different appearances and properties, in fact, scientific evidence supports both the use of hard and soft occlusal splints. Hard splints are more preferred when compared to soft ones, thus, oft appliances have been less documented in the scientific literature. However, some studies suggested the use of soft-resin splints that are easily fabricated and may be inserted at an initial appointment, dental clinicians may desire the use of soft appliances. One of the advantages of these appliances is they are easy to tolerable to the patient and comfortable. Additionally, these splints fit tightly and provide a flat plane during sleep.

Considering these advantages, the present study was designed to examine the effect of the use of different types of occlusal splints on the sleep quality and occlusal force of patients with sleep bruxism. For this purpose, the effect of two splints basically fabricated from two different materials were evaluated and compared. The null hypothesis was that the use of both occlusal splints would not change the values of sleep quality and maximum occlusal force of the patients with sleep bruxism.

Inclusion Criteria:

- Healthy participants with complete permanent dentition.

Exclusion Criteria:

• Presence of a systemic disorder that could compromise the masticatory system (e.g., neurological disorders, epilepsy, cerebral palsy, among others),
• Systemic disorder or current use of drugs that could interfere, directly or indirectly, with muscle activity,
• Inappropriate behavior and/or refusal to cooperate with dental procedures and data collection,
• Tooth loss (except for third molars),
• Soft tissue abnormalities,
• Toothache report,
• Active periodontitis (presence of periodontal pockets involvement of the supporting tissues),
• Caries lesions,
• Use of orthodontic appliances,
• Use of dental prosthesis (fixed or removable partial).
• Subjects with moderate to severe malocclusions, diagnosed by using the Orthodontic Treatment Need Index (IOTN) (scores 5 or 6 - severe and extreme need for orthodontic treatment)
• Alcohol or drug abuse,

Blinding the participants and investigator to the splint types employed in patients