Dr. Ellie Phillips · 2026-02-02 · Ellie Phillips (host)

“Everything I knew about dentistry - you turned it on its head” - Dr. Ellie with Ask A Hygienist

Health

32 research-tied claims examined: 4 contradicted 3 overstated 3 context 11 supported 11 unverified

Overstated

0:04:43 Ellie Phillips (host)overstatedlow

A study conducted in a convent through Guy's Hospital in London showed that earlier tooth loss was associated with a higher risk of early-onset dementia.

"at the dental school where I was studying in London in Guy's Hospital, they knew that they had done a study in a convent and shown that the earlier people the earlier these women there was women had lost their teeth, it appeared the more risk they were at for early onset dementia," (said at 0:04:43)

The speaker conflates details of the well-known Nun Study on tooth loss and dementia. The primary published study examining tooth loss and dementia in a religious community is from the Nun Study in the United States (not Guy's Hospital in London), which examined Catholic sisters aged 75 to 98 years old. That study found that having fewer teeth or being edentulous was associated with an increased prevalence and incidence of late-life dementia and Alzheimer's disease, not early-onset dementia (which by definition develops before age 65).

partial: Tooth loss, dementia and neuropathology in the Nun study. (Journal of the American Dental Association (1939) 2007) · cited 375x in the literature
"Longitudinal dental records supplemented data collected from 10 annual cognitive assessments of 144 Milwaukee participants in the Nun Study, a longitudinal study of aging and Alzheimer disease, who were 75 to 98 years old... Participants with the fewest teeth had the highest risk of prevalence and incidence of dementia. Edentulism or very few (one to nine) teeth may be predictors of dementia late in life." (abstract, results and conclusions, passage verified)
pubmed full study (doi)

0:25:53 Ellie Phillips (host)overstatedmoderate

Xylitol stimulates saliva production, bringing higher levels of minerals and immunoglobulins to oral tissues.

"Xylitol actually enhances that by pulling saliva into your mouth, making it even more mineralized because stimulated saliva is uber mineralized because it's like the fire department. It thinks it's coming to an emergency. So it's coming in with all its minerals and it's also full of immunoglobulins to fix your gums." (said at 0:25:53)

Xylitol (commonly consumed as chewing gum or lozenges) promotes salivary flow through gustatory and masticatory stimulation. Stimulated saliva elevates oral pH, enhances bicarbonate buffering capacity, and facilitates the delivery and clearance of saliva components that assist in enamel remineralization. However, the claim that stimulated saliva is "uber mineralized" and "full of immunoglobulins to fix your gums" overstates normal salivary physiology. Salivary stimulation does not induce an emergency surge of hyper-concentrated minerals or immunoglobulins; polyols themselves do not chemically facilitate calcium uptake beyond standard physiological salivary stimulation, and total protein/immunoglobulin concentrations generally remain stable or dilute under high salivary flow rates.

context: The oral health benefits of chewing gum. (Journal of the Irish Dental Association 2012) · cited 39x in the literature
"Chewing sugar-free chewing gum promotes a strong flow of stimulated saliva, which helps to provide a number of dental benefits: first, the higher flow rate promotes more rapid oral clearance of sugars; second, the high pH and buffering capacity of the stimulated saliva help to neutralise plaque pH after a sugar challenge; and, lastly, studies have shown enhanced remineralisation of early caries-like lesions and ultimately prospective clinical trials have shown reduced caries incidence in children chewing sugar-free gum." (abstract, results, passage verified)
pubmed
partial: Polyols and remineralisation of enamel subsurface lesions. (Journal of dentistry 2017) · cited 15x in the literature
"This controlled in vitro study showed that polyols at physiologically relevant concentrations did not promote remineralisation of enamel subsurface lesions by facilitating calcium uptake into the lesion." (abstract, conclusions, passage verified)
pubmed full study (doi)
supports: Comparative evaluation of the effects of casein phosphopeptide-amorphous calcium phosphate… (Journal of the Indian Society of Pedodontics and Preventive Dentistry 2017) · cited 23x in the literature
"Significant increase in salivary flow rate, pH, and buffering capacity from baseline to immediately after spitting the chewing gum was found in both the study groups." (abstract, results, passage verified)
pubmed full study (doi)

0:43:24 Ellie Phillips (host)overstatedlow

Instant powdered iced tea reconstituted with fluoridated water can contain up to 13 parts per million of fluoride.

"because they condense they brew the tea really strong before they then powder it and then you mix it up with fluoridated water. You can have up to 13, like around the Aluminum Company of America, in iced tea." (said at 0:43:24)

Published analyses confirm that instant powdered and prepared iced tea products contain elevated levels of fluoride relative to many other beverages, as tea plants naturally accumulate fluoride. However, measured concentrations in commercial products are substantially lower than 13 ppm. In an analysis of 44 iced tea products (including 10 granular instant powders), fluoride concentrations were below 2.0 ppm for 42 of the products, with only two samples exceeding 2.0 ppm (PMID 12459612). While reconstituting instant tea with fluoridated water or preparing extra-strong brews increases overall fluoride delivery, claiming levels up to 13 ppm overstates the concentrations documented in published beverage testing.

partial: Fluoride concentration and pH of iced tea products. (Caries research 2002) · cited 44x in the literature
"The fluoride concentrations measured were <0.6 ppm in 14 products, 0.6-1.0 ppm in 10 products, 1.1-1.5 ppm in 16 products, 1.6-2.0 ppm in 2, and >2.0 ppm in another 2 products." (abstract, results, passage verified)
pubmed full study (doi)

Unverified means no publication matching the claim was located; it does not prove the claim false. Spotted an error? See the corrections policy - disputes from the people quoted are prioritized.