Mineral Content of Human and Seal Cementum

¹ Department of Periodontology, Eastman Dental Dispensary, Rochester, New York

Cementum was separated from the dentin by microdissection of 100-µ-thick ground sections of human and seal teeth. Inorganic Ca + Mg and P were determined by chemical analysis of the cementum and dentin samples. The dentin of human teeth and seal canines had a higher Ca + Mg and P content than the cementum of the same teeth.

Teeth from individuals more than fifty years of age, with no periodontal disease, showed an increased Ca + Mg and P content of the cementum in the cervical area of the roots. Since many samples from this group represented cementum that had been exposed to the oral cavity because of gingival recession, the hypothesis was offered that the saliva might cause a secondary mineralization to take place in exposed cementum. A gradual increase, with increasing age of the tooth, was found to take place in the mineral content of apical dentin of human teeth, measured on a dry-weight basis. This was interpreted as an increased degree of mineralization.

In human cementum there was no consistent trend when the mineral content per unit dry weight of the cervical, middle, and apical root areas within each age group were compared. The (Ca + Mg)/P ratio was higher in the apical than in the cervical root area of the same teeth. This was observed in both cementum and dentin. Analysis of 6 continuously growing canines from 5-10-year-old seals indicated a tendency toward increasing mineral content of the dentin from the apical toward the cervical area of the root; i.e., from the younger toward the older tissue.

The present investigation indicated that age of the tooth should be taken into consideration when a comparison is made of the composition of teeth with diseased and healthy periodontal tissues. Based upon this investigation it will now be possible to test the hypothesis that changes in the mineral content of the cementum take place prior to, or as a result of, periodontal disease. This can be accomplished by comparing the mineral content of cementum and dentin, at different levels of the root, in teeth which have been exposed to severe periodontal disease with that of teeth with healthy periodontal structures from the same age group.

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				W Chutimanutskul, M Ali Darendeliler, G Shen, P Petocz, and M. Swain Changes in the physical properties of human premolar cementum after application of 4 weeks of controlled orthodontic forces Eur J Orthod, August 1, 2006; 28(4): 313 - 318. [Abstract] [Full Text] [PDF]