[Cementum formation in rat molar roots].

Cementum is the calcified tissue covering roots of teeth and serves as attachment sites of the periodontal ligament. Although recent studies have suggested that extracellular matrix of cementum is very similar to that of bone, cementogenesis on a biological basis is still poorly understood. There are variations in the distribution and mineral contents of cementum depending on animal age, tooth species and position within the tooth roots. This paper reviews the formation and age-related changes of cellular and acellular cementum in rat molar roots, and discusses the effect of mechanical stress to the cementum formation.