A patient presents with commissure cracking and erythema at the corners of the mouth (angular cheilitis). What is the most common predisposing factor in a complete denture patient?

Angular cheilitis (perlèche) in complete denture patients is most commonly caused by a decreased vertical dimension of occlusion. When the VDO is inadequate (over-closed bite), the corners of the mouth become folded inward (commissural folds deepen), creating a warm, moist environment that promotes colonization by Candida albicans and/or Staphylococcus aureus. The resulting commissure creases trap saliva, and the chronic moisture causes maceration, fissuring, and inflammation. Treatment involves restoring proper VDO, antifungal therapy (topical clotrimazole or miconazole), and nutritional assessment (angular cheilitis can also be caused by riboflavin/B2 or iron deficiency).