It is gratifying to know that others are carefully reading the orthodontic literature, especially when it is one of your own articles. Dr Cao is correct in noting that the cortical bone on the lingual aspect of the maxilla did not follow the same pattern as that on the buccal aspect of the mandible. Thus, conclusion number 4 should be changed to read, “Mandibular buccal cortical bone thickness decreases from posterior to anterior.” We apologize for this oversight and are glad to have it corrected.

Although it was not part of our investigation, we agree that cancellous bone might be expected to be influenced by strain patterns and might show differences that medullary thickness does not. With respect to the final point that was raised, cortical thickness of the mesodivergent subjects might be expected to fall between that of the hyperdivergent and the hypodivergent subjects. After all, variability in facial divergence and associated muscle function follow a continuous, rather than a discrete, pattern.