【名词&注释】
前磨牙区(premolar regions)、申请人(applicant)、干髓术(pulp mummification)、牙髓摘除术(pulpectomy)、卫生行政部门(health administration)、不符合(inconformity)、书面通知(written notice)、牙髓失活(pulp devitalization)、牙髓切断术(pulp amputation)、口腔前庭(vestibule of mouth)
[单选题]颊系带为
A. 唇颊黏膜移行于牙槽黏膜的皱襞
B. 口腔前庭(vestibule of mouth)沟上相当于上下尖牙或前磨牙区的扁形黏膜皱襞
C. 口腔前庭(vestibule of mouth)沟上相当于磨牙区的扁形黏膜皱襞
D. 上颌结节后内方与磨牙后垫后方间的黏膜皱襞
E. 前庭沟中线上的黏膜皱襞