This overview aimed at assessing botulinum toxin type A (BoNT-A)’s effectiveness in managing bruxism compared to a placebo, the absence of treatment, or other interventions in adults. Only systematic reviews (SRs), with or without a meta-analysis, were included. A comprehensive literature search was conducted on 16 June 2024, encompassing seven databases and grey literature sources. Experts and reference lists of the included SRs were also consulted. Study selection was conducted in two phases by two independent authors. Methodological quality was evaluated using AMSTAR-2. Overlap was assessed using the corrected covered area. The 14 included SRs addressed several outcomes. In most studies, BoNT-A showed effectiveness in reducing pain (n = 10), the frequency of bruxism events (n = 7), and the maximum bite force (n = 5). None of the SRs effectively evaluated BoNT-A’s impact on functional movements. All of the included SRs scored “critically low” and “low” confidence rates in AMSTAR-2. Only one SR attempted to assess the certainty of the evidence, although unsuccessfully. The overlap across included SRs was rated as “high”, with a corrected covered area of 10.11%. The current systematic reviews on BoNT-A for bruxism lack methodological quality, limiting the reliability of their findings. Despite evidence indicating a potential reduction in pain, bruxism events, and the maximum bite force, methodological limitations prevent definitive conclusions from being drawn. High-quality research with standardized methodologies is essential to establish BoNT-A’s efficacy and support evidence-based clinical practice.

Introduction Bruxism is characterised by a repetitive activity in the masticatory muscles that involves teeth clenching or grinding and/or forceful mandibular movements. Its management is typically initiated when individuals start experiencing the adverse effects of the condition. One of the available intervention forms is the administration of botulinum toxin type A (BoNT-A). Numerous systematic reviews have addressed the use of BoNT-A to manage bruxism; however, the results are controversial. The current overview aims to determine BoNT-A’s effectiveness for managing bruxism in relation to placebo, the absence of treatment or alternative interventions in the adult population. Methods and analysis This study will include systematic reviews (SRs), with or without meta-analysis, aiming to evaluate the efficacy of BoNT-A for bruxism in adults. A broad literature search will be carried out on Cochrane Library, EMBASE, LILACS, Livivo, PubMed/MEDLINE, Scopus, Web of Science and the grey literature. Experts in the topic and reference lists of included SRs will also be consulted. The study selection will be conducted in two phases by two independent reviewers. Data collection will be performed by one author and cross-checked by another. The methodological quality of included SRs will be evaluated using AMSTAR-II. A narrative synthesis will be employed as the formal method to combine individual study data. The overlap across studies will be quantified by the corrected covered area and illustrated by the Graphical Representation of Overlap for Overviews. Ethics and dissemination This overview does not require ethics approval, as it uses secondary data from previously published studies. The results will be disseminated through the publication in a high-impact journal. OSF of registration DOI: 10.17605/OSF.IO/RB45T.

Background: With the increasing demand for non-surgical facial rejuvenation, injectable collagen biostimulators such as poly-L-lactic acid (PLLA), calcium hydroxyapatite (CaHA), polycaprolactone (PCL), poly-D,L-lactic acid (PDLLA) and powdered polydioxanone (PPDO) have become widely used by facial aesthetic practitioners. These agents stimulate neocollagenesis, providing gradual improvement in skin firmness, elasticity and facial contour with long-lasting results. While manufacturers emphasize the efficacy and favorable safety profile of these products, adverse events such as nodules, edema, inflammatory reactions and, in rare cases, granulomas have been reported. To date, no comprehensive systematic review has evaluated the proportion and nature of adverse effects associated with all major collagen biostimulators in facial aesthetic procedures. This study aims to synthesize current evidence on the proportion of adverse events linked to injectable collagen biostimulators. Methods: The systematic review will include clinical studies involving adults undergoing facial aesthetic procedures with PLLA, PDLLA, CaHA, PCL and PPDO that report adverse events during or after treatment. The search will be conducted in six main databases: CENTRAL, EMBASE, LILACS, PubMed, SCOPUS and Web of Science. No restrictions will be applied regarding language or publication date. The screening process will occur in two phases: first, two independent reviewers will assess titles and abstracts against the eligibility criteria; second, the same reviewers will conduct full-text evaluations. Data will be synthesized narratively, with a meta-analysis of proportions performed if appropriate. Additionally, sample characteristics, treatment protocols, study design and main findings will be reported. The risk of bias will be assessed independently by two reviewers using appropriate tools, based on the study design, with the support of artificial intelligence. PROSPERO registration number: CRD420251062785.