Brin I, Ben-Bassat Y, Einy S, Koyoumdjisky-Kaye E
Hebrew University Hadassah School of Dental Medicine, Jerusalem.
ASDC J Dent Child. 1991 Sep-Oct;58(5):409-12.
The effect of premature extractions of primary molars on further development of their successors was studied. A group of forty-six children with fifty-three unilaterally extracted mandibular primary molars was examined when the successors completed their root development. Radiographs of the successors to the extracted molars and their antimeres, which served as internal controls, were taken using the long-cone technique. Crown and root length and area in cross-section, were measured from tracings of the studied teeth and crown/root ratios were calculated. Significantly (p less than 0.05) larger area ratio in the extraction group was found suggesting a smaller root area. In addition, root foreshortening for the first premolars and diminished root area for the second premolars, both successors to teeth extracted after the age of eight years, were found. Although statistically significant, all of the differences were of no clinical importance.
研究了乳牙过早拔除对其继承恒牙进一步发育的影响。对一组46名儿童的53颗单侧拔除的下颌乳牙进行了检查，检查时间为继承恒牙完成牙根发育时。使用长锥技术对拔除磨牙及其对侧同名牙（作为内部对照）的继承恒牙进行了X光片拍摄。通过对研究牙齿的描图测量牙冠和牙根长度以及横截面面积，并计算冠根比。结果发现，拔牙组的面积比显著更大（p小于0.05），表明牙根面积更小。此外，还发现8岁后拔除牙齿的继承恒牙中，第一前磨牙牙根缩短，第二前磨牙牙根面积减小。虽然这些差异具有统计学意义，但均无临床重要性。
