Stone L H, Stroner W F
Oral Surg Oral Med Oral Pathol. 1981 Jun;51(6):649-52. doi: 10.1016/s0030-4220(81)80017-5.
Maxillary molars exhibit variations in the canal morphology of the palatal root. Systems may occur in which a single palatal root contains two separate orifices, two separate canals, and two separate foramina. Other maxillary molars may have two separate palatal roots, each with one orifice, one canal, and one foramen. Another variation is one palatal root, one orifice, a bifurcated canal, and two foramina. The practitioner should be aware of variations in the canal system of the palatal roots of maxillary molars so that they can be treated more effectively.
上颌磨牙腭根的根管形态存在变异。可能会出现单一根管有两个独立开口、两条独立根管和两个独立根尖孔的情况。其他上颌磨牙可能有两个独立的腭根，每个腭根有一个开口、一条根管和一个根尖孔。另一种变异是一个腭根、一个开口、一条分叉根管和两个根尖孔。从业者应了解上颌磨牙腭根根管系统的变异情况，以便能更有效地进行治疗。
