J Korean Assoc Oral Maxillofac Surg.  2010 Oct;36(5):360-365.

Demyelination of neurofilament protein 200 immune positive never fibers in human pulp

• Jang JW
• Choi SY
• Kwon DG
• Bae YC
• Kim CS
• Lee SH

Abstract

INTRODUCTION
Mammalian tooth pulp is densely innervated by sensory nerves that are mostly C fibers and A delta fibers. However, there is evidence suggesting that many unmyelinated axons in the pulp are in fact parent meylinated axons.
MATERIALS AND METHODS
The pulp was removed from healthy premolars and 3rd molars extracted from juveniles and adults undergoing orthodontic treatment, and immunohistochemical staining were applied with NPF200 antibodies, which specifically dye myelinated axons. The specimens underwent an electron microscopy examination with diaminobenzidine (DAB) immunostaining after observation and analysis by fluorescence and confocal laser scanning microscopy.
RESULTS
The NPF200 immuno-positive axons in the radicular pulp areas were observed as bundles of many nerve fibers. Many small bundles were formed with fewer axons when firing to the coronal pulp areas and then reachrd a different direction.
CONCLUSION
Myelinated fibers innervated to the dental pulp maintain their myelins in the radicular portion, but these fibers lost myelins in the coronal portion. Afterthe loss of myelin, the size of the axoplasm also decreased.

Keyword

Human Pulp; Myelinated axons; Unmyelinated axons; Demyelination

MeSH Terms

Adult
Antibodies
Axons
Bicuspid
Demyelinating Diseases
Dental Pulp
Fires
Fluorescence
Humans
Microscopy, Electron
Molar
Myelin Sheath
Nerve Fibers
Nerve Fibers, Unmyelinated
Parents
Tooth
Antibodies

Figure

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  Fig. 1. Immunofluorescence staining on human molar pulp showing the distribution of neurofilament protein (NFP) 200-immunopositive (+) nerves. A. NFP200+ nerves are densely appeared in subodontoblastic plexus (SOP) of Raschow of coronal pulp. B, C. NFP200+ nerve bundles C in root portion branch off and project to their termination sites. The scale bar is 50 μm in A-C.

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  Fig. 2. Immunoperoxidase staining for electron microscopic observations on the neurofilament protein (NFP) 200-immunopositive nerves of human molar pulp. A, B. Many NFP200-immunopositive (+) nerves terminate in subodontoblastic plexus (SOP) of coronal pulp. Some nerves are also passing through odontoblast (OB) layer. C, D. Nerve bundles travel the root portion C and make branches before projecting to SOP of Raschow or OB layer. The scale bar is 100 μm in A and 50 μm in B-D.

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  Fig. 3. Electron microscopic observations on the neurofilament protein (NFP) 200-immunopositive (+) nerves in root and crown portions. A. NFP200+ myelinated (arrows) and unmyelinated (arrowheads) nerves are frequently observed in root portion. B. Majority NFP200+ nerves are unmyelinated (arrowheads) in coronal pulp. The scale bar is 4 μm in A and 500 nm in B.

Reference

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