Javier García-Moya, Juan Antonio Ruiz-Roca, María Pilar Pecci-Lloret, Alberta Lucchese, Dorina Lauritano, Nuria Pérez-Guzmán
Background/Objectives: Awake bruxism is a masticatory muscle activity occurring during wakefulness and expressed as tooth contact, clenching, grinding or mandibular bracing. Its diagnosis in adolescents and young adults remains controversial due to the absence of a universally accepted gold standard. This systematic review aimed to assess the diagnostic methods used for awake bruxism in this population. Methods: This systematic review followed PRISMA 2020 guidelines and was registered in PROSPERO. Searches were performed in PubMed/MEDLINE, SciELO, Scopus, Cochrane Library and Web of Science on 17 March 2026. Studies assessing diagnostic or screening methods for awake bruxism in adolescents and young adults under 35 years were included. Risk of bias was assessed using JBI, RoB 2 and QUADAS-2 tools. Results: From 418 records identified, 13 studies met the inclusion criteria. After excluding two studies with high risk of bias, 11 were included in the qualitative synthesis. The main diagnostic approaches were self-report questionnaires, ecological momentary assessment, clinical examination and portable electromyography. Self-report was useful for screening but showed limited reliability. Ecological momentary assessment improved real-time behavioural recording, while clinical signs provided complementary information. Portable electromyography provided a more objective masticatory muscle activity, although standardized diagnostic thresholds are still lacking. Conclusions: No gold standard currently exists for diagnosing awake bruxism in adolescents and young adults. A multimodal approach combining self-report, ecological momentary assessment, clinical examination and electromyography appears to be the most robust diagnostic strategy.