A.10%~20% B.20%~30% C.30%~40% D.40%~50% E.50%~60%
A.唇系帶中的纖維組織伸入腭側(cè)齦乳頭 B.唇系帶一般附著于牙槽嵴頂 C.唇系帶一般距齦緣約2~3mm D.唇系帶一般距齦緣約3~4mm E.唇系帶一般距齦緣約4~5mm