Maintenance of the Herbst Appliance for Apnoea Treatment and Complications

Objectives: To analyse and to compare between responders and non-responders the number of additional dental visits due to side effects, adjustments and breakages of an oral appliance during the treatment of patients with sleep apnoea. Methods: Forty patients diagnosed with sleep apnoea participated in this study. All these patients received a Herbst appliance with 70% of the maximum protrusion, and this advancement was progressively increased until the patient stopped snoring. Six weeks after the patient stopped snoring or the appliance did not work, polysomnography was repeated. Therapy was considered to be efficacious when a subjective improvement in symptoms was reported and a more than 50% reduction of apnoea/hypopnoea index (AHI) and an AHI value of less than 10 was observed. A 5-year follow-up period was observed and additional visits to dental clinics and the repairs needed in dental laboratories were analysed. Routine check-ups were excluded from the analysis. Data for responders and non-responders were compared using the Mann-Whitney test. Results: Four patients were excluded due to their lack of collaboration. When the new polysomnography was carried out, eighteen patients had stopped using the device most of them because of a small reduction in their AHIs. After 5 years, the subjects had made a mean of 2.5 non-scheduled dental visits per year and a mean of 0.8 Herbst repairs/relines per year had been performed by a dental technician. The most frequent non-scheduled visits were needed during the first year and they were due to acrylic breakage on the lateral telescopic attachment (60%) followed by poor retention (14%) and other adjustments to improve comfort. No significant differences were observed between responders and non-responders. Conclusions: Several technical failures are prone to occur during apnoea treatment with a Herbst appliance but they do not seem to be related to the treatment success rates.