This pilot clinical trial will evaluate whether intentional chewing of a standardized hard chewing gum for 4 weeks produces measurable changes in facial morphology in healthy adults. Twenty participants aged 20-40 years will undergo three-dimensional facial imaging (3dMD) at baseline (T0), after the 4-week chewing intervention (T1), and following a 4-5-week washout period (T2). Changes in facial soft-tissue morphology will be assessed using three-dimensional surface analysis, including heatmaps, regional surface displacement, and morphometric measurements. Secondary outcomes include self-reported muscle fatigue, soreness, adherence, and temporomandibular disorder (TMD) symptoms.