Treatment of the retained permanent molar

The effect of five different treatments for retained permanent molars was evaluated in 59 patients to develop a rational guideline for adequate therapy. The results showed that a prosthetic buildup is the proper treatment if retention develops after the growth spurt, because in these cases the extent of infraocclusion is slight and relatively stable. If retention develops before the growth spurt, immediate removal of the retained molar followed by orthodontic treatment is the way to maximal success. When retention develops during the growth spurt, the tooth affected has to be observed at 6-month intervals. In such a case, no active treatment is indicated if the neighboring teeth show no tilting and the extent of infraocclusion is minor and stable. In all other cases, the teeth affected have to be removed, followed by orthodontic closure of the edentulous space. Finally, all patients must be screened regularly, because in this investigation, new cases of retention were observed relatively frequently.     

Hypophosphatasia affecting the permanent dentition

Reports on dental abnormalities in connection with hypophosphatasia almost exclusively describe changes in primary teeth. A 23-year-old man with hypophosphatasia, first diagnosed at the age of 8 months, is described; histologically and radiographically verified signs of the condition were present in the permanent dentition. The findings included a reduced level of the marginal alveolar bone supporting the upper central incisors, which had to be extracted. The molars displayed large coronal pulp chambers. Histologically, the upper incisors demonstrated abnormal root cementum, with areas of dentin resorption, as well as disturbances of the mineralization of the coronal dentin. The patient also had signs of abnormal root resorption of molars. The potential involvement of permanent teeth puts children with hypophosphatasia at risk of developing oral complications during adolescent and adult life.     

恒牙埋伏阻生的临床分析

目的：探讨恒牙埋伏阻生的发病情况和发生原因。方法：通过模型和X线片检查,在1925例正畸门诊病例中确诊103例患者199个埋伏阻生恒牙,对其进行统计分析。结果：在199个埋伏阻生恒牙中以上颌尖牙和上颌中切牙埋伏牙数最多,分别为94个和39个,由于萌出间隙不足引起的埋伏牙数量最多本组为62个。结论：①在所有牙位中,以上颌尖牙埋伏阻生的发病率最高,下颌中切牙最低。②引起恒牙埋伏阻生的病因以萌出间隙不足最常见。     

第三届亚洲口腔颌面放射暨全国第四届口腔颌面放射学术会议纪要

目的确定不同年龄组恒牙钙化的平均值和性别差异,以使牙龄能准确评估生理年龄.方法选择1709例曲面体层片,分别记录每个恒牙的发育度分期值;计算男、女各年龄组恒牙发育度分期值的平均值及总值;绘出恒牙发育值-年龄关系曲线;计算每个恒牙牙冠及牙根发育完成时间.结果得到4～17岁年龄组恒牙发育度分期的平均值及各年龄组恒牙发育度分期总值及恒牙牙冠及牙根发育完成时间.牙冠发育完成女性比男性平均提前0.3年,牙根发育完成女性较男性平均提前0.6年.结论恒牙发育女性早于男性,恒牙发育度分期平均值表可用于评价个体恒牙发育状况.     

恒牙发育的X线研究

目的 确定不同年龄组恒牙钙化的平均值和性别差异，以使恒牙龄能准确评估生理年龄。方法 选择1709例曲面体层片，分别记录每个恒牙的发育度分期值；计算男、女各年龄组恒牙发育度分期值的平均值及总值；绘出恒牙发育值－年龄关系曲线；计算每个恒牙牙冠及牙根发育完成时间。结果 得到4－17岁年龄组恒牙发育度分期的平均值及各年龄组恒牙发育度分期总值及恒牙牙冠及牙根发育完成时间。牙冠发育完成女性比男性平均提前0．3年，平根发育完成女性男性平均提前0．6年。结论 恒牙发育女性早于男性，恒牙发育度分期平均值表可用于评价个体恒牙发育状况。     

关中地区1000个汉族人恒牙解剖形态测量

目的:了解我国汉族人群恒牙牙体形态特征,为牙体、牙髓病的临床治疗提供解剖学资料。方法:收集陕西关中地区新鲜拔除的1000个汉族人恒牙,建立形态学测量标准,分牙位进行形态学测量分析。结果:建立了切实可行的形态测量标准,提供了关中地区成人恒牙的解剖形态数据。结论:前磨牙、磨牙根分叉发生位置偏差较大。