第14题: [单项选择]患者,女,39岁,6个月前因外伤致一上前牙脱落,今要求烤瓷桥修复。口腔检查:右上中切牙缺失,间隙无明显异常,牙槽嵴高度无明显异常,较平整。左上中切牙近中切角缺损,未露髓,探稍敏感,叩诊阴性,无松动。右上侧切牙牙冠完好,叩诊阴性,无松动。上下前牙牙龈轻度红肿,易出血,可见少量菌斑及牙石,余牙未见明显异常。下列哪项关于右上侧切牙金瓷冠牙体预备的要求是正确的() A. 切端磨除2mm B. 唇面磨除2mm C. 牙体预备分次磨除 D. 唇面龈边缘在龈沟底 E. 唇面龈边缘在龈上 参考答案:A
第17题: [单项选择]Despite the rising importance and great convenience of the gyrocompass,the magnetic compass still retain its importance because of its(). A. great convenience B. finding true north C. magnetic characteristics D. simplicity and reliability 参考答案:D