Objective: To analyze the relationship between the width of the maxillary anterior teeth and the anterior arch perimeter, to analyze the change rule of the width of the anterior teeth and the anterior arch perimeter, when altered the convexity of the anterior arch, with the width of the maxillary anterior arch keeping constant, and to provide a reliable basis for later digitized and personalized aesthetic analysis of front teeth.
Methods: In the study, 61 front teeth complete and well-arranged models had been selected from the working models after the prostheses in Department of Prosthodontics, Peking University School and Hospital of Stomatology, including 22 male models and 39 female models. A photograph was taken from the occlusal surface of each model using the fixed magnification with a single lens reflex camera. The width of anterior teeth, the width of anterior arch and the convexity of anterior arch had been measured using the Photoshop software. The ratio of the width of the anterior teeth to the width of the anterior arch was calculated. Keeping the width of anterior arch unchanged, the layer free transformation function used to add or decrease the curvature of the anterior arch from 1-5 mm, each circumference of the anterior arch was measured. According to the proportion of their anterior teeth in the anterior arch perimeter, the width of each anterior teeth crown under different convexities of anterior arch was calculated. SPSS 23.0 was used to analyze the ratio of the width anterior teeth to the anterior arch perimeter and correlation between the convexity of the anterior arch and the width of the anterior teeth.
Results: The percentages of the median length of the anterior arch in the central incisor, lateral incisor and canine were 36.2%±1.3%, 30.2%±1.5%, and 33.6%±1.4%, respectively. The proportions were normal distributions and not related to the perimeter of the anterior arch. When the width of the anterior arch was constant, there was a positive correlation between the convexity of anterior arch in the range of 5 mm and the width of anterior teeth or the front arch circumference. With each increase or decrease of 1 mm of the convexity of anterior arch, the width of the middle incisor increased or decreased by about 0.18 mm, the half circumference of the anterior arch increased or decreased by about 0.50 mm.
Conclusion: The width of the anterior teeth in the middle-distal direction remained stable in the anterior arch circumference. Within a certain range, when the width of the maxillary anterior arch remains unchanged, the width of the anterior teeth and the perimeter of the anterior teeth are positively correlated to the convexity of the anterior arch.
目的: 分析上颌前牙近远中宽度在上颌前牙弓周长中所占的比例关系,分析上颌前牙弓宽度不变时,前牙近远中宽度以及前牙弓周长随前牙弓深度改变而变化的规律,为前牙数字化、个性化美学分析提供可靠依据。
方法: 在北京大学口腔医院修复科完成修复的寄存模型中选择上颌前牙牙列完整且排列整齐的模型61副,其中男性模型22副,女性模型39副。使用单反相机固定放大比例从牙合面拍摄模型,利用Photoshop软件测量照片中前牙近远中宽度、前牙弓宽度、前牙弓深度,计算上颌前牙近远中宽度在上颌前牙弓周长中所占的比例。利用Photoshop图层自由变换功能在保持上颌前牙弓宽度不变的情况下,改变上颌前牙弓深度,测量不同凸度下上颌前牙弓的周长,按照原有各个前牙在前牙弓周长中所占的比例计算出不同凸度下各上颌前牙牙冠近远中宽度。用SPSS 23.0统计软件分析上颌前牙近远中宽度在上颌前牙弓周长中所占的比例关系,以及改变上颌前牙弓深度后上颌前牙近远中宽度的变化规律。
结果: 上颌中切牙、侧切牙、尖牙在上颌前牙弓一半周长所占比例分别为36.2%±1.3%、30.2%±1.5%、33.6%±1.4%,各比例为正态分布,与上颌前牙弓周长不相关。当上颌前牙弓宽度不变,在5 mm范围内,上颌前牙近远中宽度及前牙弓周长变化与前牙弓深度变化呈正相关,前牙弓深度每增加或减少1 mm,中切牙近远中宽度增加或减少约0.18 mm,半侧前牙弓周长增加或减少约0.50 mm。
结论: 上颌前牙近远中宽度在上颌前牙弓周长中所占比例保持稳定,在一定范围内,当上颌前牙弓宽度不变时,上颌前牙近远中宽度及上颌前牙弓周长与前牙弓深度呈正相关。