*3.2.1 Age as a risk factor*

It is important to recognize that in the older adults, there are risk factors, biological and social that favor the prevalence of oral pathologies such as tooth decay and chronic periodontitis [26]. These diseases continue to appear in old age. Global data indicate that the incidence of untreated tooth decay shows an upward trend after age 60. It was suggested that this was due to the development of root decay among older people. Similarly, periodontal diseases and their sequelae are highly prevalent among older people. The age-standardized prevalence and incidence of severe periodontitis showed a slight increase worldwide during 1990-2010, with a peak incidence in the fourth decade of life [27].

From a biological perspective, the etiology of periodontal disease has consistently been related to the interaction between the microbial plaque and the host's immune response. Previous research shown, although periodontal conditions are initiated by dental plaque, the perpetuation of inflammation and the severity and progression of the disease depend on the effectiveness of the innate immune response to the bacterial biofilm. For its part, tooth decay is an essentially diet-mediated disease, in which host factors such as immune components in the microbial biofilm and saliva contribute to its progression [22].


#### **Table 1.**

*Biological and social risk factors of oral disease in old age.*

Age can affect both oral diseases directly. When analyzing national studies of older people from the USA and Germany to observe, among other issues, the vulnerability to periodontitis and tooth decay in this population. The results showed that changes in susceptibility to periodontitis with age could be explained by exposure to pro-inflammatory conditions and changes in the healing capacity of cells and tissues [26].

The greater severity of periodontal diseases with age has been related to the length of time that periodontal tissues have been exposed to dentogingival plaque and is considered to reflect the accumulated oral history of the individual. However, the susceptibility of the periodontium to microbial plate induced periodontal degradation can be influenced by the aging process or by health problems specific to the aging patient. Differences in eating habits, increased flow of gingival exudate from the inflamed gum, and possible age-related changes in salivary gland secretions can similarly alter the conditions for growth and multiplication of microorganisms in the biofilm [28].

On the other hand, due to accumulated periodontal destruction, the number of surfaces at risk of tooth decay increases. The sequelae of restorative treatment contribute to an increased susceptibility to tooth decay development. Risk indicators for root decay include tooth decay experience, number of surfaces at risk, and poor oral hygiene [26].

With regard to tooth decay and the immune system and the impact of aging, a systematic review showed that studies are still in an early stage. A small number of studies have reported components of innate and adaptive immunity that affect the composition of dental saliva and biofilms with possible impacts on caries progression. Some conclusions could, at this stage, be considered more theoretical [29].

#### *3.2.2 Medical conditions and their relationship with oral disease in old age*

The general health of older people involves a variety of medical, cognitive and functional conditions and/or limitations that can have a direct effect on the onset and progression of oral diseases. And, by extension, the self-sufficiency of older people with respect to the performance of oral hygiene and the search for timely professional dental care [27].

#### *3.2.3 Musculoskeletal conditions and oral health*

In general, obtaining medical or dental care is known to be a problem for many older people with impaired functional status, especially those who are homebound or reside in long-term care facilities. People with disabling musculoskeletal conditions are likely to be among those affected in this way.

It is estimated that 10% of the world's population aged 60 years or older have significant clinical problems attributable to osteoarthritis, a condition that is associated with joint pain, limited movement and sensation and occurs most frequently in the knee, hip and joints of the hands [30]. While the prevalence of rheumatoid arthritis is lower, it also affects a large number of people and is associated with aging [31].

Many people with these conditions, osteoarthritis and arthritis in the hands, cannot maintain proper oral hygiene, causing plaque and stone buildup, increasing the likelihood of tooth decay and periodontal disease. The limitation of mobility resulting from these diseases, particularly in the lower extremities, makes it difficult for those affected to visit dental offices for both routine hygiene and treatment [32].
