Which disease is identifiable by a cotton wool pattern of bone and hypercementosis?

The correct answer is Paget's disease, which is characterized by abnormal bone remodeling leading to increased bone turnover and distortion of bone structure. In this condition, one can observe a cotton wool pattern of bone on radiographic imaging, which represents areas of disorganized bone formation and resorption. This pattern is due to the active cellular phases of Paget's disease where there are excessive osteoclastic activity followed by compensatory osteoblastic activity.

Additionally, hypercementosis, which is the excessive formation of cementum on the roots of teeth, is often seen in patients with Paget's disease. This can lead to dental complications, including displacement or mobility of teeth, due to the thickened bone surrounding the roots.

In contrast to Paget's disease, the other options listed do not exhibit the same pathological features. For example, Kaposi's sarcoma is a vascular tumor often associated with AIDS, pemphigus vulgaris is an autoimmune blistering disorder affecting skin and mucous membranes, and dentinogenesis imperfect is a genetic disorder affecting tooth development characterized by discolored and brittle teeth. None of these conditions demonstrate the distinctive bone patterns or hypercementosis associated with Paget's disease.