Objective To find the evidence of the effect of microbiotic collagenase in root surface caries by observing the destruction of collagenous matrix on root surface.

• 目的通过对根面牙骨质基质胶原纤维降解破坏情况的超微结构观察,以寻找微生物源性胶原酶在根面龋中发生作用的证据。