Dementia and oral health

Posted by watchmen
March 16, 2024


By Dr. Joseph D. Lim

(Second of two parts)

There is emerging evidence from studies that people with dementia have poor oral health. However, the relationship between the two diseases is not clear, according to B. Daly, head of the Division of Public & Child Dental Health, Dublin Dental University Hospital, Trinity College Dublin, Ireland.

Daly led a rapid review of research published between 2005 and October 2015 to investigate the relationship between dementia and oral health. The review, undertaken by a working group comprising consultant clinicians from medicine and dentistry, trainees, public health, and academic staff, covered 11 cohort and five case-control studies. They ranged from a sample size of 59 up to 11,140 participants, with data drawn from 28 countries.

The evidence suggests that an association between oral health and dementia is weak because of the lack of well-designed cohort and case-control studies and variations in how dementia and oral health are defined and measured, Daly says.

He suggests that patients with suboptimal oral health appear to have an associated increased risk of cognitive impairment, but more evidence from different settings is required.

“There is evidence that failure to perform toothbrushing and the presence of gingival inflammation may be risk predictors associated with developing dementia,” Daly says.

Three studies found no association between measures of periodontal disease and cognitive decline, while another three studies suggest an association. The review concludes it is not clear whether periodontal disease is linked to cognitive decline. However, the risk of cognitive impairment was more than three times higher in patients with severe periodontitis compared to those with mild or no periodontitis.

There are conflicting results suggesting that progressive tooth loss was associated with increasing risk of cognitive decline. There is sufficient evidence however to suggest that this is an important area for further research.

For denture wearers, adequate masticatory function involving 10 or more upper, and six or more lower teeth, was associated with a lower risk of dementia. A four-year study in Japan showed that people with fewer teeth and no dentures were found to be at greater risk for dementia.

The rapid review highlights the paucity of evidence on the relationship between dementia and oral health over the 10-year review period, Daly says.

Still, there is some limited evidence of the impact of oral health (oral hygiene, caries and number of teeth) on dementia (cognitive impairment, dementia onset and progression), including plaque accumulation, gingivitis and notably tooth loss.

“Evidence suggests that people with dementia may experience worse oral health, with poor oral hygiene and dementia [cognitive decline/impairment] showing the most consistent association.”

“There is conflicting evidence relating to tooth loss and the risk of cognitive decline and dementia, though professional management and satisfactory treatment of oral conditions remains important in this patient group.”



Dr. Joseph D. Lim, Ed. D., is the former Associate Dean of the College of Dentistry, University of the East; former Dean, College of Dentistry, National University; Past President and Honorary Fellow of the Asian Oral Implant Academy; Honorary Fellow of the Japan College of Oral Implantologists; Honorary Life Member of the Thai Association of Dental Implantology; and Founding Chairman of the Philippine College of Oral Implantologists. For questions on dental health, e-mail or text 0917-8591515.



Dr. Kenneth Lester Lim, BS-MMG, DDM, MSc-OI, graduated Doctor of Dental Medicine, University of the Philippines, College of Dentistry, Manila, 2011; Bachelor of Science in Marketing Management, De La Salle University, Manila, 2002; and Master of Science (MSc.) in Oral Implantology, Goethe University, Frankfurt, Germany, 2019. He is an Associate Professor; Fellow, International Congress of Oral Implantologists; Member, American Academy of Implant Dentistry and Fellow, Philippine College of Oral Implantologists. For questions on dental health, e-mail

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