There are no legal requirements regarding the frequency for taking a complete medical history. It is a matter of clinical judgment with the individual patient. When determining the interval for a medical history update you should take into consideration the health and history of the patient. Updates to medical histories can include an additional complete form, verbally asking for updates and noting them on the original medical history or a supplemental form for updates. If a supplemental form is used to update the medical history, the patient should confirm the accuracy of the information and this form should be signed and dated by the patient. How often you ask patients to fill out a completely new form should depend on the patient. Common sense dictates that patients who have complicated medical histories need complete updating more often than average healthy adults.
Many electronic dental records have medical histories that are easily updated by the clinician at each visit. When using electronic records practices often have patients fill out an initial medical history on paper. The ADA has an excellent resource entitled “Dental Records” (http://www.ada.org/sections/professionalResources/pdfs/dentalpractice_dental_records.pdf) which reviews this topic. Their recommendation is that patients should be asked at each visit to see if their health status or medications have changed. The record should be updated and it should be documented that the patient was asked about changes to his or her medical history. Some practices have a policy requiring every patient to fill out a new medical history at a certain interval to maintain consistency between providers.
While it is required and recommended that you update the patient’s medical history at each visit, the decision about the frequency of filling out an entirely new medical history form is professional, not legal.