heel of tooth

例句：

1. 1. The dentist needs to remove the heel of the tooth before filling it.
   牙医需要先去除牙齿的根部，再填充。
2. 2. The patient's heel of tooth was severely damaged during the accident.
   患者在事故中严重损伤了牙根。
3. 3. The dentist advised the patient to take care of their heel of tooth regularly to prevent further damage.
   牙医建议患者定期照顾好他们的牙根，以防止进一步损伤。