Setting aside the drilling on shadows...

There are studies that link gum disease to dementia.

https://www.nia.nih.gov/news/large-study-links-gum-disease-d...

> The mouth is home to about 700 species of bacteria, including those that can cause periodontal (gum) disease. A recent analysis led by NIA scientists suggests that bacteria that cause gum disease are also associated with the development of Alzheimer’s disease and related dementias, especially vascular dementia. The results were reported in the Journal of Alzheimer’s Disease.

Going to the dentist for cleaning may be a good thing for those with less than ideal dental hygiene habits - even if no suggestions of cavities are ever drilled.