Assessing the effectiveness of smart retainers for orthodontic retention: A systematic review and meta-analysis

To evaluate the effectiveness of smart retainers in enhancing patient compliance during the retention phase of orthodontic treatment through objective measurement and behavioural feedback mechanisms.

A systematic search of PubMed, Scopus, Web of Science, EBSCOhost, and the Cochrane Library identified studies from the past 20 years. Eligible studies included randomized controlled trials, cohort studies, and observational designs assessing smart retainers with integrated sensors. Two independent reviewers conducted screening, data extraction, and quality assessment using the ROB-2 and JBI tool. Certainty of evidence for key outcomes (wear-time, relapse, periodontal indices) was assessed using the GRADE framework.

Fifteen studies evaluated smart systems including TheraMon®, Smart Retainer®, DentiTrac®, and Air Aid®. TheraMon® demonstrated the highest tracking accuracy and ease of integration. Short-term compliance improved when patients were aware of monitoring, whereas reminder systems showed mixed effectiveness. Meta-analysis of eight studies (439 participants) showed no statistically significant improvement in wear-time (SMD=0.21, 95% CI -0.39 to 0.81; MD=0.49h/day, 95% CI -0.61 to 1.59; I²=85-88%). Meta-regression indicated no significant association between study-level average wear-time and effect size (P=0.337). Leave-one-out analysis confirmed robustness. One study linked extended wear-time to reduced relapse.

Smart retainers enhance objective wear-time monitoring, but current evidence does not confirm consistent compliance improvement. Some systems appear accurate and clinically feasible; however, pooled results are non-significant and heterogeneous. Benefits should be considered uncertain, and further well-designed, long-term RCTs are needed to establish their impact on relapse prevention and treatment stability.

CRD420251029140.