Ciucchi Philip, Kiliaridis Stavros
Clinique Universitaire de Medecine Dentaire (CUMD), Department of Orthodontics, Rue Barthelemy-Menn, Geneva, Switzerland.
Eur J Orthod. 2017 Oct 1;39(5):554-559. doi: 10.1093/ejo/cjw086.
Social attractiveness is influenced by a variety of different smile-related factors. We evaluated whether the degree of upper central incisor proclination can result in tooth colour change.
Forty young adult subjects (20-25 years) in good health with a complete sound dentition were selected. The subjects were seated in standardized light conditions with an above-directed light source. Their natural head position was stated as 0 degrees. To mimic the range of possible anterior torque movements they were asked to tilt their heads upward +15 degrees (upward tilting) and downward -15 degrees (downward tilting). Frontal macro photographs, parallel to the Frankfort plane of the patient's natural head position were taken at the three head angulations (+15, 0, and -15 degrees ). Photographs were analysed for colour differences at the centre of the incisor clinical crowns with a CIE Lab* colour model based software. A paired t-test was used to test for significance between each value for each inclination.
Differences were found between the CIE Lab* colour values for: upward tilting, downward tilting, and -15 to +15 degrees (total tilting) except for b* values for downward tilting. As the inclination of the subject's head changed downward, the upper incisors were retroclined and the CIE Lab* values indicated a darker and less green but redder colour component. As the inclination of the subject's head changed upwards the upper incisors were proclined and the Lab* values indicated a lighter and less green and yellow but redder and bluer colour component.
Proclination of upper incisors caused lighter tooth colour parameters compared to retroclined incisors and colour changes. Orthodontic change of upper incisor inclination may induce alterations on how tooth colour is perceived.
社交吸引力受多种与微笑相关的因素影响。我们评估了上颌中切牙倾斜度是否会导致牙齿颜色变化。
选取40名健康的年轻成年人（20 - 25岁），他们拥有完整健全的牙列。让受试者在标准化光照条件下就座，光源位于上方。将他们的自然头部位置设定为0度。为模拟可能的前牙转矩运动范围，要求他们将头部向上倾斜 +15度（向上倾斜）和向下倾斜 -15度（向下倾斜）。在三个头部角度（+15度、0度和 -15度）下，拍摄与患者自然头部位置的法兰克福平面平行的正面宏观照片。使用基于CIE Lab*颜色模型的软件分析切牙临床冠中心的颜色差异。采用配对t检验来检验每个倾斜度下各值之间的显著性。
除向下倾斜时的b值外，向上倾斜、向下倾斜以及 -15度至 +15度（总倾斜度）之间的CIE Lab颜色值存在差异。随着受试者头部倾斜度向下变化，上颌切牙舌倾，CIE Lab值显示颜色更暗、绿色成分减少但红色成分增加。随着受试者头部倾斜度向上变化，上颌切牙唇倾，Lab值显示颜色更浅、绿色和黄色成分减少但红色和蓝色成分增加。
与舌倾的切牙相比，上颌切牙唇倾导致牙齿颜色参数变浅及颜色变化。上颌切牙倾斜度的正畸改变可能会引起牙齿颜色感知方式的改变。
