Epithelial senescence predicts salivary dysfunction in Sjögren disease and glandular integrity defines residual capacity

The SMG gland ratio reflects preserved glandular structure, while p16-mediated senescence captures functional vulnerability. Senescence peaks at an intermediate preservation stage, delineating a transitional disease phase in which function deteriorates despite intact architecture. These findings support a dual-pathology framework and may inform early risk stratification and therapeutic targeting in SjD.