Data sources The following electronic databases were searched: MEDLINE, EMBASE, PsycoINFO, Scopis, WoS, AMED, CENTRAL Open alongside the Open Grey database and Cochrane Library of systematic reviews. In addition, reference lists of included studies and systematic reviews were searched.Study selection Initial screening was undertaken by two independent reviewers against the PICO and inclusion/exclusion criteria. Discrepancies between reviewers were resolved by a third reviewer.Data extraction and synthesis Data was extracted from included studies using a standardised form. Three summary measures were calculated: prevented fraction (PF); standardised mean difference (SMD); and standardised effect size (ES). Where concerns about incomplete data were encountered, authors were contacted to provide clarification; if data was not able to be completed, the study was excluded.Results Following screening, 38 selected manuscripts explored the impact of sugar-free gum (SFG) across all aspects of oral health. From this, data was extracted from 12 studies with dental caries outcomes included; of these, eight explored xylitol gum as the intervention and were analysed separately. A significant reduction in caries incidence was found with the use of SFGs - PF of 28% (95%CI 7%-48%). In the eight trials that used xylitol-only gum as the basis of the intervention, the PF increased to 33% (95% CI 4%-61%). No adverse effects were recorded. There was a high level of heterogeneity among the trials included.Conclusions The use of SFG was shown to have a significant, but tentative, effect in reducing the incidence of caries, compared to those who do not or use other sugar-free alternatives. The authors comment that a considerable degree of variability was noted between the trials reviewed. Further research is required in this field to provide robust empirical evidence.