Herbst–multibracket appliance treatment: is there an association between lower incisor position changes and the development of labial gingival recessions?

PURPOSE: To assess a potential association between lower incisor (LI) position changes during Herbst–multibracket appliance (Herbst–MBA) treatment and the development of labial gingival recessions (LGR). METHODS: All class II patients (Department of Orthodontics, University of Giessen, Giessen, Germany) who had undergone Herbst–MBA treatment until 2015 with study models and lateral cephalograms available from before (T0) and after treatment plus ≥24 months of retention (T3) were included (n = 259). Lateral cephalograms were evaluated regarding LI position changes: iiL/ML (angle between LI long axis and mandibular plane [MP]), ii-ML(Pg) (distance between LI incisal edge and a line perpendicular to MP through pogonion), apex-ML(Pg) (distance between LI apex and a line perpendicular to MP through pogonion), ii-ML(ii) (distance between LI incisal edge and MP on a line perpendicular to MP through incisal edge). Using study models the distance between the cementoenamel junction and the deepest point of the gingival margin was defined as LGR. RESULTS: The following cephalometric mean changes were recorded (T0–T3): iiL/ML +5.9 ± 5.76° (p = 0.929), ii-ML(Pg) −0.2 ± 0.25 mm (p = 0.430), apex-ML(Pg) +0.1 ± 0.32 mm (p = 0.363), ii-ML(ii) +0.1 ± 0.36 mm (p = 0.206). The mean increase of LGR magnitude measured on the study models was 0.1 ± 0.35 mm. However, no association with the cephalometric LI position changes was found (|R| ≤ 0.2). CONCLUSION: There is no association between the amount of LI position changes and the development of LGR during Herbst–MBA treatment plus retention. Nevertheless, individual predisposition or excessive treatment changes and extraordinary treatment approaches, respectively, might still lead to development of LGR.