Real-time enzymatic degradation of human dentin collagen fibrils exposed to exogenous collagenase: an AFM study in situ.
OBJECTIVE
This study was carried out to observe the enzymatic degradation of human dentin collagen fibrils exposed to exogenous collagenase in situ using atomic force microscopy, to understand the characteristics of the enzymatic degradation of collagen fibrils on dentin specimens.


METHODS
Polished dentin specimens from caries-free third molars were etched with citric acid, and then treated with an aqueous solution of 6.5% NaOCl for 120 s. The specimen was then put into a fluid cell and treated with a mixed solution of collagenase I (MMP-1) and collagenase II (MMP-8) for 9 h. AFM with contact mode was performed in situ to monitor the enzymatic degradation process of the dentin collagen fibrils. The distinctly topographic changes of the dentin surface were recorded continuously during different stages of the enzymatic degradation process.


RESULTS
The mixed solution of exogenous collagenase I and collagenase II could degrade dentin organic matrix (mainly collagen) efficiently, and the structures of dentin substrate were clearly exposed.


CONCLUSIONS
It is possible to carry out real-time observations on the enzymatic biodegradation process of human dentin collagen fibrils on dentin specimens with atomic force microscopy in situ. By this means, the fine structures of the etched dentin substrate were clearly revealed, possibly contributing to the related study of human dentin in vitro.
Department of Conservative Dentistry and Periodontic, Affiliated Hospital of Stomatology, Medical College, Zhejiang University, People's Republic of China.
X
X
Zheng
H
H
Pan
Z
Z
Wang
H
H
Chen
D003094:Collagen / Q000378:metabolism*; D017364:Collagenases / Q000378:metabolism*; D003804:Dentin / Q000737:chemistry* / Q000648:ultrastructure*; D006801:Humans; D018625:Microscopy, Atomic Force / Q000379:methods*; D008964:Molar, Third / Q000737:chemistry* / Q000648:ultrastructure*; D013048:Specimen Handling; D013499:Surface Properties; D013997:Time Factors
D003094:Collagen; D017364:Collagenases