Immunohistochemical demonstration of nerves in the predentin and dentin of human third molars with the use of an antiserum against neurofilament protein (NFP).

Immunohistochemistry by use of an antiserum against neurofilament protein (NFP) was applied for staining nerve fibers in the predentin and dentin of human third molars. By devising methods for fixation, decalcification and immunostaining, nerve fibers were clearly and specifically demonstrated in thick (more than 50 micron) sections of teeth. Numerous NFP-positive fibers were distributed in the predentin throughout the coronal region, while a few positive fibers penetrated only a short distance into the dentin. The NFP-positive nerve fibers in the predentin took transverse and complicated courses across, rather than penetrating longitudinally through, the dentinal tubules. Pain sensation in the teeth might be attributable to these complex nerve fibers showing two- or three-dimensional extensions.