Oral Manifestations of Prediabetes: A Narrative Review of an Early Diagnostic Window for Dental Practice

Prediabetes is a common metabolic condition affecting a substantial proportion of adults worldwide; however, most individuals remain undiagnosed owing to the prolonged asymptomatic phase of this condition. The oral cavity generates a constellation of clinically detectable changes during this intermediate glycemic stage, including periodontal attachment loss, salivary dysfunction, and oral microbiome dysbiosis, all of which can be examined by dental professionals. Periodontal clinical attachment loss and elevated glycated hemoglobin (HbA1c) levels show a dose-dependent relationship in nondiabetic populations, and active matrix metalloproteinase-8 (aMMP-8) in oral fluids correlates independently with prediabetes, even in its early stages. Salivary oxidative stress markers, adipokines, cariogenic bacterial loads, and physicochemical parameters are measurably altered before overt hyperglycemia is established. Oral microbial communities show reduced species richness, altered IgA immune responses, and shifts in keystone taxa in prediabetic individuals compared to those in healthy individuals. Chairside HbA1c measurement, aMMP-8 point-of-care testing, and structured interprofessional referral models have demonstrated high diagnostic yields in real-world dental settings. This narrative review explores the current literature and proposes dental practice as a first-line venue for opportunistic prediabetes detection, with an emphasis on actionable clinical strategies for practicing dentists.