Data sources: Searches were made using the Cochrane Oral Health Group's Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL), Medline, Embase, LILACS (Latin American & Caribbean Health Sciences Literature), Biblioteca Brasileira de Odontologia, and Dissertations, Theses and Abstracts. Hand searches were made of abstracts of particular importance to this review. Additional reports were identified from the reference lists of retrieved reports and from article reviews about treating sleep bruxism. There were no language restrictions.
Study selection: Randomised controlled trials (RCT) or quasi-RCT were chosen that compared splint therapy concurrently with no treatment, other occlusal appliances, or any other intervention in participants who had sleep bruxism.
Data extraction and synthesis: Data extraction was carried out independently and in duplicate. Validity assessment of the included trials was carried out at the same time as data extraction. Discrepancies were discussed and a third review author consulted. The author of the primary study was contacted when necessary.
Results: Thirty-two potentially relevant RCT were identified of which five were eventually included. In these, use of an occlusal splint was compared with palatal splint, mandibular advancement device, transcutaneous electric nerve stimulation, and no treatment. There was just one common outcome (arousal index) which was combined in a meta-analysis. No statistically significant difference between the occlusal splint and control groups were found in meta-analysis.
Conclusions: There is not enough evidence to state that the occlusal splint is effective for treating sleep bruxism. Indication of its use is questionable with regard to sleep outcomes, but there may be some benefit with regard to tooth wear. This systematic review suggests the need for further investigation in more controlled RCT that pay attention to method of allocation, outcome assessment, large sample size, and sufficient duration of followup. The study design must be parallel in order to eliminate the bias provided by studies of crossover type. A standardisation of the outcomes of the treatment of sleep bruxism should be established in the RCT.