Heda P, Alalola B, Almeida FR, et al. - Researchers performed this retrospective study to describe the mandibular anterior teeth crown height as a marker of periodontal changes and bone loss as a side effect of an oral appliance (OA) worn for a minimum of 4.5 years. This investigation was carried out on patients with healthy baseline periodontium selected candidates from consecutive sleep apnea patients treated with an OA between 2004 to 2014. Eligible candidates were recalled for a follow-up visit where a periodontal exam was conducted, a lateral cephalogram and dental impressions were obtained. There were 21 patients registered, with a mean treatment length of 7.9 ± 3.3 years. The use of an OA significantly increases the inclination of the mandibular incisors in patients with obstructive sleep apnea. Positional changes in these teeth were not linked to any increase in clinical crown height or gingival recession.