Structure of Peripheral Cementum of Normal Equine Cheek Teeth

The structure of peripheral cementum of mandibular and maxillary check teeth was studied In gross observation, light microscopy, and scanning and transmission election microscopy Teeth from four horses aged 4, 8, 17, and 30-years-old were examined. The cementum of the occlusal surface was thicker on the buccal aspect when compared with the lingual aspect of mandibular teeth. The cementum of the occlusal surface was thicker on tin-palatal aspect when compared with the buccal aspect of maxillary teeth. There was no peripheral cementum mi the interdental aspects of either mandibular or maxillary check teeth. In the adult tooth, cementum covered the crown and root surfaces. The peripheral com mum of the gingival region showed a dramatic increase in thickness compared with cementum covering the alveolar portion of the embedded tooth. At a microscopic level, three layers (primary, secondary, and tertiary) were identified within cementum. The increase in cementum in the gingival region was of tertiary cementum. All three layers contained vital cementocytes. There was a well-developed vascular system within the cementum. Nerve bundles were also present. Three cementoblast profiles were identified at the junction of the cementum with the periodontal ligament. The results reported in this paper show that cementum is a dynamic vital tissue. These findings should contribute in ii greater understanding of the etiology and pathogenesis of cemental caries and periodontal disease in the horse.