IADR Abstract Archives
The Effect of age on Apical Periodontitis Development
Objectives: Older age is associated with reduced immune function. Our aim was to study how age affects the development of Apical periodontitis (AP), an inflammation occurring in the periodontal tissues surrounding the apices of infected teeth.
Methods: AP was induced in mice, and 2 age groups were compared (young: 6-8 weeks, adult: 8-10 months). The teeth and jaws were histologically processed and stained by Hematoxylin Eosin (H&E), Brown and Brenn (B&B), and tartrate-resistant acid phosphatase (TRAP). In addition, the samples were scanned by micro-computerized tomography (micro-CT) to evaluate the canal volume, apical constriction area, and the volume of the PA lesions. On the cellular level, cell density in the PA region was computationally assessed on H&E slides by a colorimetric evaluation software. Moreover, immune cell populations from the lesion were characterized by flow cytometry and immunofluorescence.
Results: The young group presented more canals with necrotic radicular pulp compared to the adults. There was no difference in bacteria location in the canals between the groups. Canal volume and apical constriction size were larger in the young mice compared to the adults. The periapical cell density was higher in the young group compared to the adults while the dominant immune cells in the lesions were neutrophils. All leukocyte types tested were present in higher numbers in the lesions of the young mice compared to adults, although the neutrophil presented the highest young/adult ratio. Immunofluorescence demonstrated the location of neutrophils in the lesion. More multinucleated osteoclasts were present in the lesions of the young mice, in line with the higher volume of bone resorption in the lesions of the young group.
Conclusions: Overall, we conclude that the immune reaction to AP stimuli was attenuated in the adult mice compared to the young, due to a combination of mechanical and immunological age-related changes.
Methods: AP was induced in mice, and 2 age groups were compared (young: 6-8 weeks, adult: 8-10 months). The teeth and jaws were histologically processed and stained by Hematoxylin Eosin (H&E), Brown and Brenn (B&B), and tartrate-resistant acid phosphatase (TRAP). In addition, the samples were scanned by micro-computerized tomography (micro-CT) to evaluate the canal volume, apical constriction area, and the volume of the PA lesions. On the cellular level, cell density in the PA region was computationally assessed on H&E slides by a colorimetric evaluation software. Moreover, immune cell populations from the lesion were characterized by flow cytometry and immunofluorescence.
Results: The young group presented more canals with necrotic radicular pulp compared to the adults. There was no difference in bacteria location in the canals between the groups. Canal volume and apical constriction size were larger in the young mice compared to the adults. The periapical cell density was higher in the young group compared to the adults while the dominant immune cells in the lesions were neutrophils. All leukocyte types tested were present in higher numbers in the lesions of the young mice compared to adults, although the neutrophil presented the highest young/adult ratio. Immunofluorescence demonstrated the location of neutrophils in the lesion. More multinucleated osteoclasts were present in the lesions of the young mice, in line with the higher volume of bone resorption in the lesions of the young group.
Conclusions: Overall, we conclude that the immune reaction to AP stimuli was attenuated in the adult mice compared to the young, due to a combination of mechanical and immunological age-related changes.