Tae Heon Kim1, Sook Kyung Park1, So Young Choi2, Jae Sik Lee3, Yong Chul Bae4. 1. Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, South Korea. 2. Department of Oral & Maxillofacial Surgery, School of Dentistry, Kyungpook National University, Daegu, South Korea. 3. Department of Pediatric Dentistry, School of Dentistry, Kyungpook National University, Daegu, South Korea. 4. Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, South Korea. Electronic address: ycbae@knu.ac.kr.
Abstract
INTRODUCTION: Information on the nerve fibers innervating the dental pulp is crucial for understanding dental pain and hypersensitivity. This study investigated the morphologic differences of parvalbumin (PV)-positive (+) myelinated fibers in 3 different regions of the human dental pulp. METHODS: Light and electron microscopic immunohistochemistry for parvalbumin, a marker for myelinated fibers, and quantitative analysis were performed in the apical root, core of coronal pulp, and peripheral pulp of human premolar teeth. RESULTS: About 40% of the myelinated fibers in the apical root pulp became unmyelinated in the core of the coronal pulp, and virtually all the remaining fibers became unmyelinated at the peripheral pulp. The size of myelinated axons decreased from root to peripheral pulp. PV+ axons showed extensive axonal varicosities in the peripheral pulp. CONCLUSIONS: These findings suggest that the myelinated fibers innervating the human dental pulp undergo extensive morphologic change in the extrapulpal region and in the coronal and peripheral pulp, and that PV-mediated regulation of calcium concentration and its downstream events may occur primarily in axonal varicosities in the peripheral pulp.
INTRODUCTION: Information on the nerve fibers innervating the dental pulp is crucial for understanding dental pain and hypersensitivity. This study investigated the morphologic differences of parvalbumin (PV)-positive (+) myelinated fibers in 3 different regions of the human dental pulp. METHODS: Light and electron microscopic immunohistochemistry for parvalbumin, a marker for myelinated fibers, and quantitative analysis were performed in the apical root, core of coronal pulp, and peripheral pulp of human premolar teeth. RESULTS: About 40% of the myelinated fibers in the apical root pulp became unmyelinated in the core of the coronal pulp, and virtually all the remaining fibers became unmyelinated at the peripheral pulp. The size of myelinated axons decreased from root to peripheral pulp. PV+ axons showed extensive axonal varicosities in the peripheral pulp. CONCLUSIONS: These findings suggest that the myelinated fibers innervating the human dental pulp undergo extensive morphologic change in the extrapulpal region and in the coronal and peripheral pulp, and that PV-mediated regulation of calcium concentration and its downstream events may occur primarily in axonal varicosities in the peripheral pulp.