研究者们相信这种下颚的结构和特征与鸟类和非鸟类恐龙均具有联系。
The structure and characteristics of the jaw are associated with birds and not non-avi
科研人员给上颚的左犬齿（比较尖的那颗）或者是下颚的左犬齿注射一个短的电脉冲。
The researchers delivered short electrical pulses to either the upper left canine tooth (the pointy one) or the lower left canine tooth in the subjects.
问题：位于中央位置的门牙是非常容易受到腐蚀的，而下颚的门牙则直接则特别容易遭受磨损。
PROBLEMS: The central incisors are most vulnerable, but those in the lower jaw are particularly affected by teeth grinding, which 8 per cent of us do unconsciously.
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