It is common sense that practicing good oral hygiene equates to healthier gums and teeth. Not only does it diminish the number of cavities, gingivitis, and promote proper healing and regeneration of the oral tissues, but the general public would be gratefully spared from the pungent smells of bad breath. Recently, Paganini-Hill and colleagues reported that the benefits of good dental habits are not only limited to that of the buccal cavity—it is also associated with a lower risk of dementia in older adults.

The effect of oral hygiene on the general health of elderly people is a topic that has garnered increasing interest over the recent years. As the severity of cognitive impairment and dementia escalates, individuals tend to have fewer teeth, more dental caries, more periodontal disease, less use of dentures, and poorer oral hygiene. Furthermore, these mounting denture-related problems have created an additional burden for caregivers. Thus, it is necessary to decipher the relationship between oral hygiene and dementia such that early interventions can be implemented to reduce cognitive impairment in the elderly.

Although cross-sectional studies have shown that dental health behaviors are related to cognitive ability, no longitudinal study has examined dental health practices as potential risks factors for dementia until recently. Here, the authors hypothesized that better preventive dental health behaviors would be related to lower risk of dementia. The study followed a large cohort of 6,173 elderly men and women (median age 81) for up to 18 years. Individuals were instructed to complete postal health surveys asking about their dental health status and behaviors. Questions included inquiries regarding the number of natural teeth, dentures worn, number of visits to a dentist, and oral health habits. Participants were also asked to indicate how often they brushed their teeth in the morning, at night before bed, and during the day; cleaned their dentures; and used dental floss, mouth wash, and tooth pick. Dementia cases were identified from follow-up questionnaires, hospital records, death certificates, and in-person evaluations.

It was found that men with inadequate oral hygiene habits who did not wear dentures had a 91% greater risk of dementia than those with adequate oral hygiene habits. This risk was also associated with women, although not significant. Additionally, dentate individuals who did not brush their teeth daily had a 22-65% greater risk of dementia than those who brushed their teeth three times a day. Implementing tools such as dental floss, mouth wash, or a tooth pick had little effect on risk. Dementia risk was also greater in men who paid infrequent visits to their dentist compared to those who had seen their dentist two or more times in a year. For denture wearers, cleaning dentures was not significantly related to dementia risk.

What potential mechanisms are behind these findings? There have been a few studies that have prospectively evaluated oral health and its relationship to the development of cognitive impairment and dementia. Potential mechanisms include infection and inflammation, lower extracellular acetylcholine release, and nutrition. One study found that individuals with Alzheimer’s disease were more likely to have the oral Treponema bacteria in their brains than in controls. Additionally, periodontal disease and tooth loss have been associated with arteriosclerosis, heart disease, and stroke, which are in turn risk factors for dementia.

Either way, practicing good oral hygiene is an admirable habit regardless of age, sex, or cognitive ability. If you are not doing so already, perhaps these findings will help you to adopt such changes in your lifestyle. Not only will you enjoy the aesthetic perks of a whiter smile, but you would potentially lower your risk at forgetting where you last left your keys. So, prevent that fridge door from being unnecessarily opened and start brushing!

References

Avlund K, Holm-Pedersen P, Morse DE, Viitanen M, & Winblad B (2004). Tooth loss and caries prevalence in very old Swedish people: the relationship to cognitive function and functional ability. Gerodontology, 21 (1), 17-26 PMID: 15074536

Chalmers JM, Hodge C, Fuss JM, Spencer AJ, & Carter KD (2002). The prevalence and experience of oral diseases in Adelaide nursing home residents. Australian dental journal, 47 (2), 123-30 PMID: 12139265

Meurman JH, & Hämäläinen P (2006). Oral health and morbidity–implications of oral infections on the elderly. Gerodontology, 23 (1), 3-16 PMID: 16433636

Paganini-Hill A, White SC, & Atchison KA (2012). Dentition, dental health habits, and dementia: the leisure world cohort study. Journal of the American Geriatrics Society, 60 (8), 1556-63 PMID: 22860988

Stewart R, & Hirani V (2007). Dental health and cognitive impairment in an English national survey population. Journal of the American Geriatrics Society, 55 (9), 1410-4 PMID: 17767683

Wu B, Plassman BL, Crout RJ, & Liang J (2008). Cognitive function and oral health among community-dwelling older adults. The journals of gerontology. Series A, Biological sciences and medical sciences, 63 (5), 495-500 PMID: 18511753

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