A.與牙根的長(zhǎng)度一致 B.根長(zhǎng)的1/2 C.根的1/3 D.根長(zhǎng)的2/3~3/4 E.根長(zhǎng)的4/5
A.不保留 B.1~2mm C.2~3mm D.3~5mm E.5~7mm
A.無(wú)肩臺(tái) B.0.5~0.8mm C.1.0mm D.1.7mm E.2mm