短语词组短语root canal apex locator 根管测量仪Root apex position 根尖位置root apex root tip 根尖root apex infammation 根尖周炎divergence Of root apex 根尖分岐plant root apex 植物根尖Root apex to back 根锥顶至安装基准面距离dental root apex 牙根尖 返回 root apex