What is a disadvantage of nonresorbable guided bone regeneration (GBR) membranes?

The correct answer highlights a significant drawback of nonresorbable guided bone regeneration (GBR) membranes: the necessity for reentry procedures to remove the membrane after healing has occurred. Nonresorbable membranes do not break down within the body over time, which means that after they have successfully guided the regeneration of bone, a surgical procedure is required to retrieve the membrane. This adds an extra layer of complexity to the treatment process, increases the patient's time in treatment, and poses additional risks associated with a second surgical site.

In contrast, resorbable membranes do not have this drawback since they naturally dissolve in the body after fulfilling their purpose, eliminating the need for an additional surgery. While nonresorbable membranes may offer advantages such as better mechanical stability in certain scenarios, their removal requirement is a notable disadvantage that practitioners must consider when planning treatment.