title: Changes in the Distribution of Periodontal Nerve Fibers during Dentition Transition in the Cat.
abstract: The periodontal ligament has a rich sensory nerve supply which originates from the trigeminal ganglion and trigeminal mesencephalic nucleus. Although various types of mechanoreceptors have been reported in the periodontal ligament, the Ruffini ending is an essential one. It is unknown whether the distribution of periodontal nerve fibers in deciduous teeth is identical to that in permanent teeth or not. Moreover, morphological changes in the distribution of periodontal nerve fibers during resorption of deciduous teeth and eruption of successional permanent teeth in diphyodont animals have not been reported in detail. Therefore, in this study, we examined changes in the distribution of periodontal nerve fibers in the cat during changes in dentition (i.e., deciduous, mixed and permanent dentition) by immunohistochemistry of protein gene product 9.5. During deciduous dentition, periodontal nerve fibers were concentrated at the apical portion, and sparsely distributed in the periodontal ligament of deciduous molars. During mixed dentition, the periodontal nerve fibers of deciduous molars showed degenerative profiles during resorption. In permanent dentition, the periodontal nerve fibers of permanent premolars, the successors of deciduous molars, increased in number. Similar to permanent premolars, the periodontal nerve fibers of permanent molars, having no predecessors, increased in number, and were densely present in the apical portion. The present results indicate that the distribution of periodontal nerve fibers in deciduous dentition is almost identical to that in permanent dentition although the number of periodontal nerve fibers in deciduous dentition was low. The sparse distribution of periodontal nerve fibers in deciduous dentition agrees with clinical evidence that children are less sensitive to tooth stimulation than adults.
authors.affiliation: Department of Oral Anatomy and Developmental Biology, Osaka University Graduate School of Dentistry, Osaka, Japan; Department of Periodontology, Osaka University Graduate School of Dentistry, Osaka, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Miki
authors.affiliation: Department of Oral Anatomy and Developmental Biology, Osaka University Graduate School of Dentistry, Osaka, Japan; Department of Oral Health Sciences, Faculty of Nursing and Health Care, Baika Women's University, Osaka, Japan.
authors.forename: Shiho
authors.initials: S
authors.lastname: Honma
authors.affiliation: Department of Anatomy, Meiji University of Integrative Medicine, Kyoto, Japan.
authors.forename: Satomi
authors.initials: S
authors.lastname: Ebara
authors.affiliation: Department of Anatomy, Meiji University of Integrative Medicine, Kyoto, Japan.
authors.forename: Kenzo
authors.initials: K
authors.lastname: Kumamoto
authors.affiliation: Department of Periodontology, Osaka University Graduate School of Dentistry, Osaka, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Murakami
authors.affiliation: Department of Oral Anatomy and Developmental Biology, Osaka University Graduate School of Dentistry, Osaka, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Wakisaka
mesh_terms: D000818:Animals; D002415:Cats / Q000033:anatomy & histology*; D003817:Dentition; D008334:Mandible / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D009412:Nerve Fibers / Q000648:ultrastructure*; D010513:Periodontal Ligament / Q000166:cytology / Q000294:innervation*; D011859:Radiography; D014094:Tooth, Deciduous / Q000166:cytology / Q000294:innervation*