Method: 147 mandibulars were manipulated using clearing technique, then the apical and lateral foramina of all the teeth were investigated under stereomicroscope.

• 方法:将147个下颌第三磨牙制作成透明标本,用体式显微镜对根尖孔和侧孔数目及分布进行观察和统计。结果:147个下颌第三磨牙中,融合根有66个,分叉根有81个。