Each tooth that sits within the maxilla or mandible is surrounded by softer alveolar bone. Dense cortical bone covers the exposed surface of the alveolar process as well as the underlying cancellous bone (see Fig. 12.1). The actual tooth socket is lined with thin, compact bone that is penetrated by blood vessels, lymphatics, and nerves. Connective tissue fibers (“Sharpey fibers”) of the periodontal membrane hold the teeth to the surrounding bone. With dental loss, the surrounding alveolar process undergoes atrophy.