Oral Mucosal Pathology and Systemic Toxicity of Bleaching Agents and Amalgam Restoration in Patients with Gastrointestinal Disorders

Abstract

Background: Dental bleaching agents and amalgam restorations are widely used in clinical dentistry, but their potential effects on oral mucosal tissues and systemic health remain a matter of clinical interest. Patients with gastrointestinal disease may be more prone to oral mucosal changes as a result of changes in saliva, reflux irritation, medications and nutritional changes. Objective: To assess oral mucosal pathology and selected systemic toxicity indicators associated with bleaching-agent exposure and amalgam restorations in patients with gastrointestinal disorders. Methodology: This descriptive analytical cross-sectional study was conducted at Peshawar Dental College, Peshawar from January 2025 to June 2025. Non-probability consecutive sampling was used to select a total number of 77 patients with gastrointestinal disorders. Demographic Data, Gastrointestinal Disease Profile, Exposure to Dental Bleaching Agents, Presence and Duration of Amalgam Restorations and Orofacial Mucosal Findings were documented. Selected biochemical parameters such as liver and renal function tests, systemic symptoms, were also measured when available. The associations of dental exposure and oral mucosal pathology were assessed by chi-square or Fisher's exact test with adjustment for potential dental exposure confounders by using multivariable logistic regression. All p-values were interpreted as being statistically significant at the p-value <0.05 level. Results: Oral mucosal pathology was identified in 39 (50.6%) participants. Burning sensation, mucosal erythema, xerostomia, pigmentation, and lichenoid changes were the most commonly observed abnormalities. Mucosal pathology was more frequent among participants exposed to bleaching agents than among non-exposed patients (66.7% vs 43.4%, p=0.049) and among those with amalgam restorations compared with those without restorations (63.2% vs 38.5%, p=0.030). The highest frequency was observed among participants exposed to both bleaching agents and amalgam restorations (73.3%). Combined exposure was also associated with modest differences in alanine aminotransferase and serum creatinine levels. Conclusion: Bleaching-agent exposure and amalgam restorations were associated with a higher frequency of oral mucosal abnormalities in patients with gastrointestinal disorders, particularly when both exposures were present. Although modest systemic biochemical variations were observed, the findings do not establish direct systemic toxicity. Larger prospective studies are required to clarify the clinical significance of these associations.