The 'lifespan' of mandibular repositioning appliances.

Introduction Mandibular replacement appliances (MRAs) can be used in the treatment of snoring, mild to moderate obstructive sleep apnoea and as a second-line treatment where continuous positive airway pressure (CPAP) fails. There is currently a paucity of evidence as to how long these appliances last.Aims Assess the replacement rate for MRAs using this as a proxy for lifespan; estimate the period prevalence of temporomandibular joint disorder (TMJD) and bruxism in the study population.Methods Prospective observational study as part of service evaluation. Data from consecutive patients seeking a replacement MRA were collected over a three-month period, yielding a sample of 60. The mean time between the provision of appliances was calculated in months. Reasons for replacement were sought, collated and categorised. Patients were asked to report any TMJD symptoms and bruxing.Results The mean replacement rate was 36.7 months. The main reasons for replacement were: device condition; fit and reduced effectiveness; and other minor reasons reported. Period prevalence of TMJD was 6.7%; bruxism was reported in 5% of patients.Conclusions A 'lifespan' of ust over three years for thermoplastic MRAs is estimated. The main reasons for replacement were: condition, poor fit and reduced effectiveness. MRAs do not appear to increase the frequency of TMJD and bruxism.