Wednesday, July 30, 2025
The study investigates the effects of orthodontic treatment on gingival morphology symmetry in patients with mild anterior crowding and skeletal Class I malocclusion. Using digital intraoral scans, the researchers measured parameters such as mean deviation distance (MDD), root mean square (RMS), and percentage within tolerance. Significant statistical differences were observed in these measurements before and after orthodontic treatment, with a p-value < 0.001. No significant differences were found between the post-orthodontic group and the control group in most gingival symmetry parameters. However, a statistically significant difference was observed in the changes of MDD and RMS across tooth positions. Orthodontic treatment enhanced gingival contour symmetry in patients with mild anterior crowding and skeletal Class I malocclusion. A comparison of the gingival morphology symmetry in anterior teeth between post-orthodontic patients and healthy individuals revealed no statistically significant differences. This study was approved by the Biomedical Research Ethics Committee of Stomatology Hospital of Fujian Medical University (approval no. 2024-14). A smile is a reflection of coordinated facial movements, and achieving an aesthetically pleasing smile primarily requires consideration of facial aesthetics, which enables dental professionals to develop a treatment approach from the aesthetic perspective. Psychological and anthropological studies show that symmetrical faces are generally perceived as attractive and healthy [1]. Although facial symmetry enhances attractiveness, smile symmetry plays a more critical role in aesthetic perception. Studies show that a symmetrical smile enhances aesthetic resonance by reducing visual tension, while slight facial asymmetry adds charm through its personalized characteristics. Therefore, smile symmetry contributes more to overall aesthetic appeal and pleasure than facial symmetry [2]. A beautiful and symmetrical smile results from the harmonious integration of facial aesthetic factors [3] and oral aesthetic factors [4], with oral symmetry playing a decisive role in the visual appeal of a smile [5,6,7]. Darby’s study demonstrated that oral symmetry can significantly enhance the beauty and pleasantness of a smile, even when there are slight asymmetries in other facial areas [8]. Similarly, well-aligned teeth and symmetric gingival morphology are considered key factors in enhancing the harmony of a smile [9,10,11,12,13]. In oral aesthetics research, Pham and Nguyen [14] further confirmed that symmetry in gingival morphology significantly impacts the visual attractiveness of a smile. Zhang [15] indicated that the dynamic symmetry of the gingival contour during smiling greatly influences the perception of gingival aesthetic parameters. Collectively, these studies highlight the crucial role of gingival symmetry in improving the aesthetic appeal of a smile, which complements overall smile symmetry. In orthodontic treatment, the alignment of teeth and aesthetic improvement in patients with malocclusion are often the primary concerns of both clinicians and patients. However, the critical factor of gingival symmetry changes is frequently overlooked. Maxillary anterior crowding (MxAC) is a common issue in orthodontic treatment [16], characterized by labial or buccal displacement of the canines and palatal displacement of the lateral incisors [17]. This type of malocclusion is mainly caused by a mismatch between tooth size and arch length, not only leading to functional problems [18] but also significantly impacting the patient’s aesthetic appeal [19]. Orthodontic treatment can typically improve the symmetry of tooth alignment and enhances overall aesthetics [20]. However, existing studies indicate that in some orthodontic patients, after teeth are properly aligned, the visual aesthetic balance may be compromised due to asymmetry of the gingival margin in either the vertical or horizontal planes [21, 22]. This asymmetry can reduce the aesthetic outcome of orthodontic treatment and negatively affect patient satisfaction. At the same time, we understand that laser therapy has potential in reshaping gingival contours and enhancing gingival symmetry [23, 24]. Currently, most research on smile aesthetics in malocclusion patients focuses on the impact of orthodontic treatment on tooth symmetry, while the symmetry and changes in gingival morphology before and after orthodontic treatment have not received sufficient attention. With advancements in digital oral scanning technology, obtaining high-precision and reproducible 3D models of the oral cavity now provides comprehensive three-dimensional data on tooth and gingival morphology [25]. Through reverse engineering techniques and 3D surface matching algorithms, deviation analyses can be conducted to derive three-dimensional symmetry assessments [6, 26,27,28]. A review of the current literature indicates that there are limited methods or studies available that objectively assess gingival morphological symmetry within the dental arches of orthodontic patients before and after treatment. This study aims to assess changes in gingival morphological symmetry before and after orthodontic treatment in patients with mild anterior crowding and skeletal Class I malocclusion using digital models, to explore the impact of orthodontic treatment on gingival symmetry. The null hypotheses of this study are: (1) There is no significant difference in gingival contour symmetry in patients with mild anterior crowding and skeletal Class I malocclusion before and after orthodontic treatment; and (2) After orthodontic treatment, gingival symmetry in patients with mild anterior crowding is not significantly different from that of individuals with normal occlusion. The current retrospective study was ethically reviewed and approved by the Biomedical Research Ethics Committee of Stomatology Hospital of Fujian Medical University, China (approval no. 2024-14).
Reference: Orthodontic treatment improves gingival morphological symmetry parameters: a retrospective studyLabels: BMC Oral Health
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