Department of Orthodontics, RWTH Aachen University, 52074, Aachen, Germany.
Eur J Orthod. 2024 Oct 1;46(5). doi: 10.1093/ejo/cjae046.
This study aims to verify Bolton's values for tooth size ratios and to evaluate possible relationships to different occlusal traits using precise digital measurement methods.
Including 1000 consecutively selected patients from three study centres a digital, partially automated model analysis was performed utilizing the software OnyxCeph. The measurements comprised tooth width for calculation of anterior (AR) and overall ratio (OR) as a percentage, arch width, length, perimeter, overjet, overbite, space analysis in millimetre and the assessment of the angle classification.
AR and OR were significantly increased compared to Bolton's ratios of 77.2% (AR) and 91.3% (OR). In the gender comparison, male patients showed larger tooth size ratios, especially in the OR. Patients with Angle Class II/1 and II/2 had smaller tooth size ratios than patients with Angle Class III and I. Thus, patients with Angle Class II/1 had the largest tooth diameters in all maxillary teeth and with Angle Class II/2 the smallest tooth sizes in the mandible. The largest tooth widths in the lower jaw were observed in the Angle Class III patient group. Furthermore, a negative correlation from AR/OR to overjet, overbite, and available space in lower jaw as well as a positive correlation to available space in upper jaw was detected.
There is a clear correlation between the tooth size ratios and the present dysgnathia as well as other orthodontically relevant occlusal traits. This prior knowledge about our patients is extremely important to create an individualized treatment plan and enable sufficient occlusion. To achieve a functionally good occlusion with correct overjet and overbite, it is essential that the maxillary and mandibular teeth are proportional in size. Any deviation from the ideal patient in terms of tooth size, number, shape, or arch must be considered in the pre-therapeutic treatment plan in combination with the existing dysgnathia in order to be able to achieve a stable anterior and posterior occlusion with appropriate adjustments to the therapy post-therapeutically.
本研究旨在通过精确的数字测量方法验证 Bolton 的牙齿大小比率，并评估其与不同咬合特征的可能关系。
从三个研究中心连续选择 1000 名患者，使用 OnyxCeph 软件对数字、部分自动化模型进行分析。测量包括计算前牙（AR）和总比（OR）的牙宽，以百分比表示，牙弓宽度、长度、周长、覆盖、覆合、毫米间隙分析和角度分类评估。
AR 和 OR 明显高于 Bolton 的 77.2%（AR）和 91.3%（OR）比率。在性别比较中，男性患者的牙体尺寸比率较大，尤其是 OR。Angle Class II/1 和 II/2 的患者的牙体尺寸比率小于 Angle Class III 和 I 的患者。因此，Angle Class II/1 的患者上颌所有牙齿的牙径最大，Angle Class II/2 的患者下颌牙最小。下颌牙中，Angle Class III 患者组的牙宽最大。此外，还发现 AR/OR 与下颌覆盖、覆合和可用间隙呈负相关，与上颌可用间隙呈正相关。
牙体尺寸比率与当前的错牙合以及其他正畸相关的咬合特征之间存在明显的相关性。了解患者的这些情况对于制定个体化治疗计划和实现充足的咬合非常重要。为了实现功能良好的咬合，正确的覆盖和覆合，上颌和下颌牙齿的大小必须成比例。在治疗前的治疗计划中，必须考虑到患者的牙齿大小、数量、形状或牙弓与理想患者的任何偏差，以及现有的错牙合情况，以便能够在治疗后进行适当的调整，实现稳定的前、后牙咬合。
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