title: Cementum on Smilodon sabers.
abstract: The maxillary canines of Smilodon californicus Bovard, 1907 have a deeply curved cementoenamel junction. The gingiva of modern cats is attached to the tooth at the cementoenamel junction and provides tactile and other dental information to the animal. The presence of cementum at the cervix of the maxillary canines, also called sabers, would indicate that the gingiva in Smilodon was attached in this region. Such an attachment would be advantageous, providing stability and sensory input for the large tooth. Also, gingiva at the cervix would impact the manner in which the teeth were used. Previous study using scanning electron microscopy of dental casts was indirect. The purpose of this study was to confirm by direct methods the presence of cementum at the cervix of Smilodon californicus sabers. Parts of three Smilodon californicus sabers were sectioned and examined with light and scanning electron microscopy (EDS). In addition, percent weight of calcium and phosphorus was measured in enamel, dentin, and cementum using electron dispersive spectroscopy. Cementum was identified in the cervical region of each saber. Spectroscopy confirmed that the tissue is calcified and the mineral is hydroxyapatite. Percent calcium and percent phosphorus of individual tissues were highly variable between specimens. However, the ratios of calcium to phosphorus were not significantly different from the hydroxyapatite standard. In the future, bite models will have to take the presence of soft tissues into account.
authors.affiliation: School of Dentistry, Oregon Health and Sciences University, Portland, Oregon 97201, USA. rivierefam@att.net
authors.forename: Holliston L
authors.initials: HL
authors.lastname: Riviere
authors.forename: H Todd
authors.initials: HT
authors.lastname: Wheeler
mesh_terms: D000818:Animals; D002118:Calcium / Q000032:analysis; D002415:Cats; D003481:Cuspid / Q000033:anatomy & histology* / Q000737:chemistry; D003739:Dental Cementum / Q000737:chemistry / Q000648:ultrastructure*; D003743:Dental Enamel / Q000737:chemistry / Q000648:ultrastructure; D003804:Dentin / Q000737:chemistry / Q000648:ultrastructure; D004577:Electron Probe Microanalysis; D045989:Felidae / Q000033:anatomy & histology* / Q000502:physiology; D005881:Gingiva / Q000033:anatomy & histology; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D010163:Paleontology; D010758:Phosphorus / Q000032:analysis
chemical_list: D010758:Phosphorus; D002118:Calcium