Antimicrobial activity and material compatibility of Anatolian essential oil–based oral care formulations

Medicinal plants have long been used in Anatolia for the management of infections and oral health–related conditions. Essential oils obtained from these plants are traditionally valued for their antimicrobial properties; however, their applicability in modern oral care formulations (mouthwashes) and their compatibility with oral biomaterials remain insufficiently explored. This study aimed to evaluate the antimicrobial activity of region-specific essential oil–based mouthwash formulations prepared using Salvia triloba, Origanum vulgare, Lavandula angustifolia, and Myrtus communis, and to assess their compatibility with commonly used restorative materials. Glass ionomer and resin-based restorative materials were immersed in herbal essential oil–based mouthwash formulations to simulate 1- and 5-year clinical exposure periods. Weight change was recorded, while color stability was assessed using the CIEDE2000 (ΔE₀₀) formula, and antimicrobial activity was determined by the minimum inhibitory concentration (MIC) method. The physical effects of herbal mouthwash formulations were material-dependent; in glass ionomer cement, weight change was affected by mouthwash type and duration (p < 0.05), while in resin-based materials color change remained within clinically acceptable limits (ΔE₀₀ < 1.8). All herbal formulations exhibited antimicrobial activity, as indicated by MIC values, with the lowest MIC values observed for the O. vulgare mouthwash against S. mutans and C. albicans (0.02%), while the strongest antifungal activity against C. albicans was noted for the M. communis formulation (0.05%). The demonstrated antimicrobial efficacy together with acceptable effects on restorative materials suggests that essential oil–based mouthwash formulations derived from Anatolian medicinal plants provide a favorable balance between antimicrobial activity and material compatibility.