Synthetic study of the causes of non carious cervical lesions

对现代日本人6572颗牙齿进行了非龋齿性宫颈病变（NCCL）检查：从中门牙到第二磨牙，左右两侧，上颌骨和下颌骨。其中犬齿和第一前臼齿的NCCLs发生率最高（40~60%）。大多数牙齿的颊侧（唇侧）发生ncll最多，第二磨牙的舌侧发生ncll最多。根据NCCLs的表面轮廓（线状、水平椭圆形、垂直椭圆形、带状、不规则）和截面形状（圆形、楔形、光滑、不规则）对其形态进行分类。额牙舌面以纵圆型为主，前磨牙颊面以绳楔型为主，臼齿中、远面以水平圆型为主。

Non carious cervical lesions (NCCL) were examined on modern Japanese 6572 teeth: from central incisors to the second molars, on left and right sides, on maxilla and mandibles. The frequencies of NCCLs were the highest on canines and the first premolars (40~60%). NCCLs were most frequently found on buccal (labial) sides on most teeth, but on the second molars, on lingual sides. The morphology of NCCLs were classified by the contour on the surface ( cord, horizontal oval, vertical oval, belt, irregular ) and the shape on the cross section ( round, wedge, smooth, irregular ). On the lingual surfaces of frontal teeth, vertical – round type was dominant, on the buccal surfaces of premolars, cord – wedge type was dominant, and on the mesial and distal surfaces of molars, horizontal – round type was dominant.