Statement of problem

Anterior tooth selection is an important step in complete denture treatment as it plays a pivotal role not only in esthetics but also in mastication and pronunciation. However, conventional methods for tooth selection are not well established and rely on facial measurements and proportions, which vary among different ethnicities.

Purpose

The purpose of this clinical study was to investigate the relationship between interalar width and intercanine distance and to compare different clinical methods for determining the position of the canine tooth.

Material and methods

Two hundred Thai participants (100 men and 100 women) aged 18 to 25 years with 6 full maxillary anterior teeth were enrolled in this study. The interalar width and intercanine distance were measured with digital vernier calipers and compared by using the paired-samples t test. To determine the canine position, 2 reference lines—the alar line (A line) and the inner canthus of the eye to alar line (IA line)—were drawn through the canine on both sides. The horizontal distances from each reference line to the canine cusp tip and distal contact point were evaluated and then analyzed using the 1-sample t test.

Results

All measurements were significantly different between men and women (P<.01). Interalar width was greater than intercanine distance in both sexes. In men, the A line coincided with the canine distal contact point (P>.05). In contrast, the IA line was distal to the canine distal contact point by 3.5 ±3.6 mm on the left side and by 3.9 ±3.4 mm on the right side. In women, the A line was situated between the canine cusp tip and distal contact point. It was mesial to the distal contact point by 2.0 ±2.0 mm on the left side and by 1.8 ±2.0 mm on the right side. The IA line was distal to the canine distal contact point by 1.2 ±2.6 mm on the left side and by 1.6 ±2.7 mm on the right side.

Conclusions

The interalar width is greater than the intercanine distance in both sexes. The A line is more clinically relevant than the IA line for predicting canine position. The A line can directly determine the distal contact point of the canine in edentulous male patients. However, in women, a distance of approximately 2 mm should be added distal to the A line to locate the distal contact point of the canine on both sides.

中文翻译：

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通过多个面部标志确定尖牙位置以实现全口义齿治疗中的自然美学

问题陈述

前牙的选择是全口义齿治疗的重要步骤，它不仅对美观而且对咀嚼和发音起着举足轻重的作用。然而，传统的牙齿选择方法并没有很好地建立起来，而是依赖于面部尺寸和比例，这在不同种族之间是不同的。

目的

本临床研究的目的是调查牙间宽度和尖牙间距之间的关系，并比较确定尖牙位置的不同临床方法。

材料与方法

200 名泰国参与者（100 名男性和 100 名女性）年龄在 18 至 25 岁之间，拥有 6 颗完整的上颌前牙，参与了这项研究。使用数字游标卡尺测量牙间宽度和尖牙间距离，并使用配对样本t检验进行比较。为了确定尖牙的位置，通过两侧的尖牙绘制了 2 条参考线——鼻翼线（A 线）和眼内眦至鼻翼线（IA 线）。评估从每条参考线到尖牙尖端和远端接触点的水平距离，然后使用 1 样本t检验进行分析。

结果

男性和女性的所有测量值都存在显着差异 ( P <.01)。Interalar 宽度大于 intercanine 距离在两性。在男性中，A 线与尖牙远端接触点重合 ( P >.05)。相比之下，IA 线在左侧远离尖牙远端接触点 3.5 ± 3.6 毫米，在右侧远离 3.9 ± 3.4 毫米。在女性中，A 线位于尖牙尖端和远端接触点之间。它在左侧距远端接触点近中 2.0 ±2.0 mm，在右侧距远侧接触点 1.8 ±2.0 mm。IA 线在左侧远离尖牙远端接触点 1.2 ±2.6 mm，在右侧远离 1.6 ±2.7 mm。

结论

两性的牙间宽度都大于尖牙间距离。对于预测尖牙位置，A 线比 IA 线更具临床相关性。A线可以直接确定无牙男性患者尖牙的远端接触点。然而，对于女性，应在 A 线远端增加约 2 毫米的距离，以定位两侧尖牙的远端接触点。