A.2mm B.5mm C.8mm D.10mm E.15mm
A.與黏膜密合 B.離開(kāi)0.5~1mm C.離開(kāi)1.5~2mm D.離開(kāi)2.5~3mm E.離開(kāi)3.5~4mm
A.1~2mm B.3~4mm C.5~6mm D.7~8mm E.9~10mm