True or false: Generalized bone loss is defined as affecting more than 30% of the sites in the dentition.

• A. True
• B. False
• C. Not defined
• D. Sometimes true

Answer: (A)

Generalized bone loss is defined by its widespread involvement across the dentition. The standard criterion uses a site-based measure: if bone loss is present in more than 30% of the sites in the dentition, it is considered generalized. Remember, there are up to six sites per tooth, so in a full dentition the threshold involves a substantial number of sites (more than about 50 of 168 in a typical adult mouth). This distinction helps differentiate widespread periodontal destruction from localized disease, which affects a smaller proportion of sites. Therefore the statement is true.