Focused Clinical Question: How should cases of altered passive and active eruption be diagnosed, classified, and treated?Summary: Frequently, a “gummy smile” contributes to esthetic problems and is caused by several factors such as vertical maxillary growth, dentoalveolar extrusion, short upper lip, upper lip hyperactivity, altered passive eruption (APE), or a combination of these factors. APE is a genetic or developmental condition characterized by coronal positioning of the gingival margin over enamel, resulting in short clinical crowns. Active eruption is defined as tooth movement in the occlusal direction as the tooth erupts from its osseous crypt. Altered active eruption (AAE) occurs when teeth achieve the opposite relationship to the occlusal plane prematurely and the osseous crest is on or very close to the cemento‐enamel junction. Thus, correct understanding of biologic events related to APE and AAE should be considered in the classification of a gummy smile. This article proposes a modification of a previous clinical classification and provides a surgical guide for treatment planning of cases involving APE and/or AAE. Periodontal biotypes are also taken into consideration.Conclusions: This article proposes modification of a previous classification dealing with two eruptive processes known as AAE and APE. Clinical cases and schemes enable understanding and treatment planning of different conditions.

Background: The aim of this study was to evaluate the cytotoxicity of cyanoacrylate adhesives in an indirect contact assay in human gingival fibroblast (FGH) and oral osteoblasts (GO) lineages. Methods: Cover glasses were glued with adhesives following the ISO 10993-2012 protocol. The groups were: C (control with cells and regular Dulbecco Modified Eagle Medium; LC (liquid ethyl-cyanoacrylate); GC (ethyl-cyanoacrylate gel); EGC (easy gel [ethyl-cyanoacrylate]); and D (Dermabond [octyl-cyanoacrylate]). Each cell linage was plated in the sixth passage using 10⁴ cells. Cell viability was measured by the MTT test at 24, 48, 72, and 96 hours. Data were analyzed by two-way analysis of variance complemented by the Tukey test, with p < 0.05 being significant. Results: Dermabond stimulated osteoblast viability at 72 h (p < 0.05). All other groups were similar to the control cells (p > 0.05). For the fibroblasts, there was no difference in the groups, including the control except that EGC was cytotoxic for these cells (p < 0.05). Conclusions: Ethyl-cyanoacrylate gel and liquid forms available on the general chemical market were not cytotoxic for oral osteoblasts and fibroblasts in most cases. However, the easy gel form was cytotoxic for fibroblasts.