Effects of Different Types of Toothpaste on Fasting Blood Glucose Levels in Diabetic Individuals: A Systematic Review of Pre-Test/Post-Test Studies

Abstract

Background: Toothpastes marketed as sugar-free, herbal, probiotic, paraprobiotic or diabetes-specific are sometimes presumed to influence glycaemia. The evidence relevant to fasting blood glucose (FBG), however, is easily conflated with studies of salivary glucose or periodontal outcomes. Objective: To determine whether different toothpaste formulations alter FBG in individuals with diabetes and, secondarily, whether they affect other systemic glycaemic outcomes such as glycated haemoglobin (HbA1c). Methods: A systematic review was conducted for 1 January 1990 to 30 May 2026 and reported in accordance with PRISMA 2020, PRISMA-S and SWiM. A completed open-source verification search covered PubMed/MEDLINE, PubMed Central and Europe PMC, Crossref, DOI and publisher records, DOAJ, the Cochrane Library, ClinicalTrials.gov, the Clinical Trials Registry–India, WHO ICTRP, and backward and forward citation checking. Subscription-database exports were unavailable; therefore, no unverified Embase, Scopus, Web of Science, CINAHL or PsycINFO counts were reported. Eligible studies compared toothpaste types in people with diabetes and measured FBG, fasting plasma glucose or HbA1c. Salivary glucose alone was not accepted as a systemic glycaemic outcome. Risk of bias was assessed with RoB 2, and certainty was judged using a structured GRADE-informed approach. Results: The manually preserved candidate log contained 12 source records; three duplicate source records were removed, leaving nine unique full-text reports. Eight were excluded: three measured salivary glucose only, two reported no systemic glycaemic outcome, and three did not compare toothpaste types. One randomised trial (40 adults with type 1 diabetes) was included. It compared a paraprobiotic toothpaste-plus-mousse protocol with a natural-extract toothpaste protocol after professional oral hygiene. No FBG outcome was reported. Mean HbA1c changed from 7.04% to 6.82% in the paraprobiotic group and from 7.29% to 7.10% in the natural-extract group over six months; the study reported no significant between-group differences. Overall risk of bias raised some concerns, and certainty for a toothpaste-specific effect on HbA1c was very low. Conclusions: No direct evidence demonstrates that one toothpaste type lowers FBG in people with diabetes. The single indirect HbA1c trial did not isolate toothpaste effects from professional periodontal care, brushing instruction or an additional mousse. Salivary-glucose findings cannot be interpreted as evidence of systemic glycaemic benefit. Well-powered, preregistered trials with FBG and HbA1c as prespecified outcomes are required.