Osteocalcin expression in young and aged dental pulps as determined by RT-PCR

Dental pulps were obtained from third molars of young adults (17-25 yr) or from molar teeth of individuals > 50 yr of age and examined for the expression of osteocalcin (OC) mRNA by RT-PCR. OC was selected as a determinant of pulp vitality, because it has long been associated with the production of hard tissue matrix in teeth and bone. For comparative purposes, the expression of OC in each pulp was normalized relative to its housekeeping gene-product GAPDH by the establishment of a OC/GAPDH ratio. This study demonstrated that OC expression, presumably by cells of odontoblast lineage, does not diminish relative to the extant cell population. Our findings suggest, despite a reduction in volume and cell numbers, that the pulps of aging teeth retain a capacity for dentin deposition and a potential for caries and trauma resistance.