Vertucci F J
J Am Dent Assoc. 1978 Jul;97(1):47-50. doi: 10.14219/jada.archive.1978.0443.
Four hundred mandibular first premolars and 400 mandibular second premolars were decalcified, injected with dye, and made transparent to determine the number of root canals, their type, the ramifications of the main root canal, the location of apical foramina and transverse anastomoses, and the frequency of apical deltas. The mandibular first premolar had one canal at the apex in 74.0% of the teeth, two canals at the apex in 25.5%, and three canals at the apex in 0.5% of the teeth. The mandibular second premolar had one canal at the apex in 97.5% and two canals at the apex in 2.5% of the teeth.
选取400颗下颌第一前磨牙和400颗下颌第二前磨牙，进行脱钙、染料注射并使其透明化处理，以确定根管数量、根管类型、主根管分支情况、根尖孔和横向吻合的位置以及根尖分歧的发生率。下颌第一前磨牙根尖处有1个根管的牙齿占74.0%，有2个根管的牙齿占25.5%，有3个根管的牙齿占0.5%。下颌第二前磨牙根尖处有1个根管的牙齿占97.5%，有2个根管的牙齿占2.5%。
