上颌中切牙
牙根吸收
异常(物理)
词根(语言学)
医学
牙冠(牙科)
牙科
门牙
口腔正畸科
吸收
内科学
物理
凝聚态物理
语言学
哲学
标识
DOI:10.1111/j.1600-0722.1972.tb00268.x
摘要
abstract – An anomaly is described, the symptoms of which have hitherto received but little attention and have been misinterpreted, viz. abnormally short roots of characteristically plump shape mainly affecting both maxillary central incisors. The author calls it Short Root anomaly or, in short, the SR‐anomaly. This paper describes a method for radiographically measuring “the relative root length” which permits quantitative comparisons of the roots in clinical series. Clinical, radiographic and metric examinations were performed on 112 children with abnormally short roots of the maxillary central incisors, 66 children with certain types of external root resorption of the maxillary incisors, and 100 children with normally developed roots used as a control group. The findings, together with available data from the scanty literature, suggest the following conclusions: (1) Irrespective of sex, the length of the root of the maxillary central incisor (“relative root length”) is, on the average, 1.6 times that of the length of the crown, and the corresponding ratio in children with SR‐anomaly is 1.1. (2) The SR‐anomaly is associated with a predisposition to root resorption in the maxillary front teeth. (3) The shortness of the roots is not due to resorption or to any developmental disturbance of exogenous origin. The condition is a constitutional anomaly and its prevalence varies with sex, race and hereditary predisposition.
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