HISTOLOGICAL ASSESSMENT OF ALBINO RATS PERIODONTAL LIGAMENT IN DIFFERENT AGES COMPARING ITS WIDTH WITH HUMAN IN CORRESPONDING AGES

Introduction: The periodontal ligament is a complicated connection tissue system connecting the alveolar bone to root surface, like any other tissue periodontal ligament undergoes changes by age either in its fibers, ground substance, cells or blood vessels. Aim of the work: This work aimed to assess the histological changes of periodontal ligament in different ages of albino rats and correlating these changes with corresponding human ages. Material and Methods: 30 rats were divided evenly into 2 groups (15 rats each). Group 1: 6 months old group and Group 2: 24 months old group rats. Rats were terminated by I.V. overdose of sodium thiopental, the mandibles of the rats were excised to allow for laboratory processing for H&E stain, Masson's trichrome stain and Periodic acid –Schiff (PAS) with subsequent examination, 30 periapical films from two categories of persons aged between 16-18 years and 68-72 years old. Results: Histologically, group 2 showed significant reduction in immature fibers, cells and ground substance. Statistically, regarding morphometric analysis of periodontal ligament width in periapical human films, there were no significant difference in width between oblique and apical regions in both rats and human. Both experimental rats and human showed increased PDL width by age Conclusion: There is gradual reduction in fibers and cellularity of periodontal ligament by aging. However, periodontal ligament width mostly increased by age in rats and in examined periapical films in human.