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过小牙(microdontia),故名思义就是牙齿过小,属于牙齿形态异常。而按统计学定义应用“牙齿大小与解剖测量平均值相比,小于二位标准差”。该病临床发生率极低。1995年9月22日,一位70岁患因左下牙痛来我院就诊,既往健康。检查中发现:牙冠畸形,除早年拔除外其余牙齿未见异常,经进一步观察发现,牙体形态,小于对侧同名牙1/2以上,呈圆锥形,排列于正常牙列之中。对进行测量后结果如下:(mm)颊舌经为2.5;近远中经为2.8;牙冠高度3.9,而各项值分别为:7.5:5.7;8.2计算显示小于二位标准差,故确诊为过小牙。在临床上过小牙发生率很低,日常见于上颌侧切牙,其次为第三磨牙及额外牙,而该患出现为过小牙,无临床症状,X 线显示牙根细小且何近中弯曲,无髓室、无根管,触诊时无松动。见于以上特征,且患者年龄之大实属罕见。
Too small teeth (microdontia), the name suggests is the teeth too small, belonging to abnormal tooth morphology. By the statistical definition of the application of “the average tooth size and anatomical measurements compared to less than two standard deviation.” The clinical incidence of the disease is very low. On September 22, 1995, a 70-year-old patient came to our hospital for treatment because of a left lower toothache and was previously healthy. Inspection found: dental crown deformity, in addition to the early removal of the rest of the teeth without exception, after further observation found that the morphology of the tooth, less than the same name on the opposite side of the ½, was conical, arranged in the normal dentition. The results of the measurements were as follows: (mm) 2.5 on the buccolingual buccal and lingual surface, 2.8 on the near and far, 2.8 on the crowns, 3.9 on the crowns, and 7.5: 5.7 on the 8.2 calculations. Too small teeth. In the clinical incidence of small teeth is very low, common in the maxillary lateral incisors, followed by the third molars and additional teeth, and the patient appears to be too small teeth, no clinical symptoms, X-ray shows small root and near bending , No pulp chamber, no root canal, palpation without loosening. Found in the above characteristics, and the patient's age is rare.