Tissular senescence and modifications of oral ecosystem in the elderly: risk factors for mucosal pathologies

The aim of this present review is to describe the pathogenesis and mechanisms behind mucosal pathologies in the elderly including a description of the risk factors for these pathologies. The oral cavity - and particularly oral mucosae - is exposed to many stresses as well as physical, chemical, thermic and pathogenic agents. In the elderly, mucosae are less resistant to the insults, and this increases the occurrence of diseases. Several factors contribute to the prevalence of mucosal pathologies with aging. There are two categories: intrinsic factors linked to the senescence of the tissues and functions, and extrinsic factors related to the older people general health status. The intrinsic factors are: 1) mucosal senescence which induces fragility 2) immunosenescence which causes a decrease in the host response against micro-organisms and an increase in the autoimmune diseases and 3) senescence of salivary glands and reduction of the saliva protective function. Furthermore, there are extrinsic factors which contribute to change the oral ecosystem during aging, such as polypathologies and polymedications, malnutrition, degradation of oral hygiene, pathogen proliferation (mainly bacteria and Candida species) and old or ill-fitted removable dentures. In the elderly several diseases occur on the oral mucosae: inflammation, bacterial infections or candidiasis, ulcerations, autoimmune dermatosis, tumoral processes. This review describes some common oral mucosal pathologies in the older people, which illustrate the impact of different risk factors described in the first part.