Data sourcesCochrane Central Register of Controlled Trials (CENTRAL), LILACS, Scopus, Web of Science, Medline and Embase.Study selectionHuman randomised controlled trials evaluating the effectiveness of reminders in orthodontics were included. Interventions including any form of participant reminder compared to a control. There were no limitations in terms of publication year, language or status. Primary outcomes measured were periodontal parameters and rate of attendance. Six secondary outcomes were also measured.Data extraction and synthesisStudy selection and data extraction were carried out independently by two reviewers, with a third reviewer utilised to resolve disagreements. Authors were also contacted if any further clarification was required with regards to missing data. Risk of bias was assessed using the Cochrane tool. Comparable outcomes were collated and analysed using a random-effects model, with corresponding 95% confidence intervals.ResultsFourteen parallel randomised controlled trials met the inclusion criteria. Only nine contributed to the meta-analyses, as five were deemed high risk of bias. Of the trials, ten RCTs, six RCTs, five RCTs and four RCTs measured plaque scores, gingival scores, rate of appointment attendance, and the effectiveness of reminder on the development of white spot lesions (WSLs) respectively. Results were grouped into either short term (1-3 months) or long term (>3 months) outcomes. In the short term, gingival condition was healthier in the reminders group (SMD = -0.66 with 95% CI: -0.97 - 0.35) and a statistically significant difference favouring patients receiving reminders was also seen in terms of plaque control (SMD = -0.38 with 95% CI: -0.65 to -0.10). In the long term, similar outcomes were recorded, with a statistically significant SMD for plaque scores and gingival scores when reminders were used (SMD -1.51 with 95% CI: -2.72 to -0.30 and SMD -1.94 with 95% CI: -3.81 to -0.07 respectively). Development of WSLs and risk of failure/cancellation were also lower in the reminder group.ConclusionsThis systematic review highlights that there is moderate to high quality evidence showing the positive effect of reminders on oral hygiene and appointment adherence in orthodontic patients. The authors suggest further high quality RCTs with longer follow-ups would be beneficial to support the efficacy of this intervention.