# Proof Narrative: Chronic periodontal disease and atherosclerotic cardiovascular disease

## Verdict

**Verdict: PROVED**

The dental literature really does say what the claim says it says — and a cardiology body that is openly skeptical of dental claims agrees on the narrow point this claim actually makes.

## What Was Claimed?

The claim is that chronic gum disease — periodontitis — has been linked to a higher risk of atherosclerotic heart and vascular disease in adults, and that the major consensus reviews on the subject treat systemic inflammation as a plausible biological pathway connecting the two. Three specific sources are named: a 2013 joint workshop by the European and American periodontology societies (Tonetti and Van Dyke), a 2020 consensus report co-organized with the World Heart Federation (Sanz and colleagues), and a 2013 review by Cullinan and "Ford."

A person might care about this for two reasons: they want to know whether the claim sometimes made in dental offices about flossing being heart-healthy is supported by literature, or they are reading a paper that makes this assertion in passing.

## What Did We Find?

The two named consensus reports — Tonetti and Van Dyke 2013, and Sanz and colleagues 2020 — say exactly what the claim says they say. The 2013 report concludes that longitudinal studies show a statistically significant excess risk for atherosclerotic cardiovascular disease in people with periodontitis, independent of established cardiovascular risk factors. The 2020 update reaffirms this, citing what its authors call "a significant body of evidence to support independent associations between severe periodontitis and several non-communicable diseases, in particular cardiovascular disease."

The third named citation requires a small correction. There is no "Cullinan and Ford, 2013" paper — the 2013 review on this topic in *Periodontology 2000* is by Cullinan and **Seymour**, and Ford is co-author on a different paper from 2009. The corrected source still makes exactly the assertion attributed to it: that the weight of evidence supports an association between periodontitis and cardiovascular disease, and that this association is supported by "biologically plausible mechanisms, including direct infection, systemic inflammation and molecular mimicry." This is the right paper; the name is a slip of the keyboard.

For independent corroboration, the 2012 American Heart Association scientific statement was also checked. That document is, if anything, the toughest critic of the broader perio-cardio story in the literature — it explicitly **rejects** a causative relationship — and yet it still affirms that "observational studies to date support an association between periodontal disease and atherosclerotic vascular disease independent of known confounders." Hearing the same associational conclusion from a cardiology body that is openly skeptical of the dental field's stronger claims is much stronger than four agreeing voices from inside periodontology would have been.

The literature has not stood still since these reviews. Recent critical appraisals (Carra and colleagues 2024) and Mendelian-randomization studies have probed whether the association is actually **causal** — and have generally concluded that the causal case has not been made. But none of them argues that the **association itself** has been overturned, or that systemic inflammation is implausible as a mediating mechanism. They argue, narrowly, that "associated with" is the right verb and "causes" is not. The claim under review uses "associated with."

## What Should You Keep In Mind?

This is a proof about **association** and **biological plausibility**, not about causation. A claim that periodontal treatment **prevents** heart attacks, or that periodontal disease **causes** atherosclerosis, would require a different and much stricter proof — and on the current evidence would not reach this verdict. Mendelian-randomization studies, which use genetic instruments to probe causality, have so far failed to find genetic causality. The AHA 2012 statement is explicit: "they do not, however, support a causative relationship."

What surprised the analysis: the cited "Cullinan & Ford, 2013" paper does not exist. This is a common kind of citation error — wrong second-author name on an otherwise-correctly-cited paper — and is not unique to this claim. The fact that the substitute paper says exactly what the user attributed to it is fortunate; if it had not, the verdict would have been different.

What this evidence does **not** address: whether treating periodontitis lowers a patient's actual risk of heart attack or stroke. The same consensus reports that affirm the association are clear that intervention trials have not yet demonstrated that periodontal therapy prevents cardiovascular events. "Floss your teeth and you will not have a heart attack" is not what this claim says, and not what this proof proves.

## How Was This Verified?

The full verification process is documented in [the structured proof report](proof.md) and [the full verification audit](proof_audit.md), and you can [re-run the proof yourself](proof.py) — the script fetches each cited source, finds the exact quoted text on the page (or, where PubMed serves a reCAPTCHA challenge, on the Wayback Machine archive), and only then counts the source toward the threshold. Four out of four sources were verified against their cited pages; the threshold for proof is three.
