1) The document discusses several vesicular and bullous lesions that can occur in the oral cavity, including herpes simplex, varicella zoster, hand foot and mouth disease, and herpangina. 
2) These lesions are generally characterized by fluid-filled vesicles or bullae that can be intra-epithelial or sub-epithelial in nature. They may present as singular lesions or in clusters.
3) The document covers the clinical features, causes, investigations and management of these common vesiculo-bullous conditions affecting the oral mucosa.