Synthetic study of the causes of non carious cervical lesions

对现代日本6572颗牙齿的非龋性牙颈部病变（NCCL）进行了检查：从中切牙到第二磨牙，左右两侧，上颌骨和下颌骨。 NCCL在尖牙和第一前磨牙上的发生率最高（40~60%）。NCCL最常见于大多数牙齿的颊（唇）侧，但在第二磨牙，舌侧。根据表面轮廓（线状、水平椭圆形、垂直椭圆形、带状、不规则形）和横截面形状（圆形、楔形、光滑、不规则形）对NCCL进行形态学分类。前牙舌面以直圆型为主，前磨牙颊面以索楔型为主，磨牙近中、远中面以横圆型为主。

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.