Microfibrillar components in dental pulp: presence of both type VI collagen- and fibrillin-containing microfibrils

Microfibrillar elements were isolated from developing and formed bovine dental pulp by a procedure involving bacterial collagenase tissue digestion and chromatography on Sepharose CL-2B. Two microfibrillar assemblies could be demonstrated. Type VI collagen microfibrils with a characteristic periodicity of about 100 nm appeared as long, thin, flexible filaments. In a number of cases these structures aggregated by lateral association. Microfibrils of 10-14 nm dia were identified as containing fibrillin on the basis of their distinctive, periodic, beaded morphology. In addition to long, single strands there were instances of chains coalescing to give amorphous aggregates. No differences in the type of microfibrillar assemblies were evident between developing and formed pulp, although fibrillin-containing microfibrils were more abundant in formed pulp.