Nart, JoseCarrió, NeusValles, CristinaSolís-Moreno, CarolsNart, MariaReñé Ramírez, RamonEsquinas López, CristinaPuigdollers Pérez, Andreu2021-05-262021-05-262014-11-010022-3492https://hdl.handle.net/2445/177662Background: some authors have reported that after orthodontic treatment (OT), a 'gummy smile' might develop. Nevertheless, there are no studies in the literature that investigate whether OT increases the presence of altered passive eruption (APE). The primary aim of this cross-sectional study is to evaluate the prevalence of APE after OT (OT group) and compare it with patients who never received OT (control group). A secondary aim is to identify which variables are related to APE. Methods: the study population consisted of 190 patients (95 patients each in the control and OT groups), providing 1,140 anterior teeth for the clinical examination. The following clinical parameters were assessed: presence or absence of APE, clinical crown length, and gingival biotype, which was divided into three categories: thin-scalloped, thick-flat, and thick-scalloped. Results: twenty-eight patients (29.5%) were diagnosed with APE in the control group and 40 (42.1%) in the OT group, although this difference was not statistically significant (P = 0.07). Furthermore, 34 (75.6%) patients with thick-flat biotype were diagnosed with APE, whereas 30 (31.3%) and four (8.2%) with thick-scalloped and thin-scalloped biotypes, respectively, had APE. These differences were statistically significant (P <0.001). Conclusions: it was concluded that: 1) the prevalence of APE is higher after OT but not to a statistically significant degree and 2) APE is more common in individuals with a thick-flat gingival biotype.6 p.application/pdfeng(c) American Academy of Periodontology, 2014OrtodònciaDentsFisiologiaOrthodonticsTeethPhysiologyinfo:eu-repo/semantics/article6615712021-05-26info:eu-repo/semantics/openAccess25126692