ON THE DERIVATION OF CELL KINETICS FROM HISTOMORPHOLOGY, OBSERVED IN THE RAT INCISOR ODONTOBLAST

A method to extract cell kinetic information from histomorphology is presented. Each replicating tissue is essentially an ordered structure with an origin where cells are formed and a periphery toward which they are displaced. the displacement path is called the tissue radius. the tissue variables may be studied in two domains, space and time. the first embraces all the states a cell may assume while the second specifies the cell transition rates. During steady state both domains are related linearly. These ideas are illustrated in the rat incisor odontoblast population whose life expectation is determined by the tooth wall shape. the odontoblast cell population paves the interior of the tooth wall delimiting a cone‐shaped pulp. Near the root apex the dentine wall is barely visible. As one proceeds distally, the wall thickens while the pulp narrows. Pulp narrowing is associated with odontoblast cell loss whose magnitude may be deduced from the change of the pulp circumference CI(x) (x is the distance from tooth origin). the odontoblast force of mortality μ(x) may be calculated from the instantaneous perimeter change: μ(x) = ‐CI' (x)/CI(x); where CI'(x) stands for the derivative of CI(x). This equation serves for the construction of the odontoblast life table which may be studied in space and time.