Absence of more than two first premolars or absence of a first and a secondpremolar.
缺少超过两个第一前臼齿或者一个第一和一个第二前臼齿。
2
Conclusion: Mandibular secondpremolar after pulling, the third molar eruption clearance increased obviously, conduce to the jaw third molar normal eruption.
结论:拔除下颌第二前磨牙后,第三磨牙萌出间隙明显增大,有助于下颌第三磨牙的正常萌出。
3
A dilute solution of 5-10 MLS sodium hypochlorite was inadvertently injected into the maxillary sinus during root canal therapy of a right upper secondpremolar (5).