ADA NBDE National Board Dental Part II

Answer: A - The three histological distinct areas of the epithelium are the oral, sulcular, and juctional epithelium. The oral epithelium is a continuous lining of attached gingiva. It is composed of keratinized stratified squamous epithelium. The sulcular epithelium exists on the secular side of free gingival; it is nonkeratinized. The juctional epithelium is attached to the tooth by hemidesmosomes at the sulcus of the sulcular epithelium. The cells are large and nonkeratinized.