AimThis study aimed to identify the risk factors for gingival invagination during orthodontic treatment after premolar extraction.Materials and MethodsThe medical records of 135 patients who had undergone interdental space closure after premolar extraction were collected, and cone beam computed tomography was performed to determine the presence of gingival invagination. The risk factors were examined using mixed‐effects models and generalized propensity score weighting (GPSW) to develop a predictive model.ResultsUnivariate analysis revealed that the extraction site, buccal bone thickness 4 mm apical to the cemento‐enamel junction (MB1), mid‐root buccal bone thickness (MB2) and vertical skeletal relationships were related to gingival invagination (p < .05). Furthermore, a subsequent multivariable mixed‐effects model analysis indicated a significantly increased risk of gingival invagination at MB1 < 1 mm (p < .001; odds ratio [ORMB1≤0.5mm] = 29.304; 95% confidence interval [CI]: 8.986–93.807; OR0.5<MB1<1mm = 22.309; 95% CI: 9.890–50.320). Row mixing model analysis performed after balancing covariates using GPSW showed that MB1 and vertical skeletal relationships were associated with gingival invagination (p < .05) with an increase in ORs. Therefore, in addition to MB1, the risk of gingival invagination is higher in hyperdivergent and normodivergent patients. During the establishment and internal validation of the predictive model, the area under the curve for all three models exceeded 0.7.ConclusionsThe risk of gingival invagination is higher in patients with MB1 < 1 mm and in normodivergent or hyperdivergent patients.

中文翻译：

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牙龈内陷的危险因素：一项回顾性研究


目的本研究旨在确定拔除前磨牙后正畸治疗中牙龈内陷的危险因素。材料和方法收集 135 例前磨牙拔除后牙间隙闭合患者的病历资料，进行锥形束计算机断层扫描以确定是否存在牙龈内陷。使用混合效应模型和广义倾向评分加权 （GPSW） 检查风险因素以开发预测模型。结果单因素分析显示，拔牙部位、牙骨质-牙釉质交界处顶端 4 mm 的颊骨厚度 （MB1） 、中根颊骨厚度 （MB2） 和垂直骨骼关系与牙龈内陷有关 （p < .05）。此外，随后的多变量混合效应模型分析表明，在 MB1 < 1 mm 时牙龈内陷的风险显著增加 （p < .001;比值比 [ORMB1≤0.5mm] = 29.304;95% 置信区间 [CI]：8.986–93.807;OR0.5<MB1<1mm = 22.309;95% CI：9.890–50.320）。使用 GPSW 平衡协变量后进行的行混合模型分析显示，MB1 和垂直骨骼关系与牙龈内陷相关 （p < .05），并且 OR 增加。因此，除了 MB1 之外，高发散度和正常发散度患者发生牙龈内陷的风险更高。在预测模型的建立和内部验证过程中，所有三个模型的曲线下面积均超过 0.7.结论MB1 < 1 mm 患者和正常发散或超发散患者牙龈内陷的风险更高。