This is an excellent question.
Certainly, Dr. Maibaums biology training helped him in his basic-science courses in dental school. While biology is a difficult discipline and an important building block of all health sciences, a degree in biology may not be considered a "health service" degree. Degrees in health service areas relate to the clinical practice of dentistry or a health care area. An example is any degree in a recognized specialty area.
Section 5.F.3. of the ADA Principles of Ethics and Code of Professional Conduct states, "A dentist may use the title Doctor or Dentist, DDS, DMD or any additional earned, advanced academic degrees in health service areas in an announcement to the public." The same section also states, "The use of a nonhealth degree in an announcement to the public may be a representation which is misleading because the public is likely to assume that any degree announced is related to the qualifications of the dentist as a practitioner." The last paragraph of the same section states, "In all instances, state law should be consulted." For more information on the ADA Council on Ethics, Bylaws and Judicial Affairs (CEBJA) report on Section 5.F.3, please go to "www.ada.org/prof/prac/law/code/principles_rep5f3.asp".
In any review by CEBJA of the use of designations in advertising to the public, the Council will apply the standard of whether the use of such is false or misleading in any material respect. An ethics committee asked to review such usage will be guided by state law.
I believe Dr. Maibaums primary concern will be for the patient. If he uses the degree in materials viewed by the public or potential patients, he should state exactly what the degree represents. He may use the degree in curriculum vitae, scientific articles, letterhead and biographical information not addressed to patients.
Dr. Maibaums question and previous training suggests he is dedicated to patient care and education. Those values, along with quality dentistry, are more likely to distinguish him as an exceptional professional.