CDT Codes Every Dentist Should Know: D0120 vs. D0150

If you handle your own billing, two codes show up constantly: D0120 and D0150. Getting the difference right matters more than it might seem. It affects how quickly you get paid and whether a claim gets quietly downgraded by the payer before it ever reaches your bank account.

D0120: Periodic Oral Evaluation

This is the routine recall exam that happens alongside a cleaning every six months for an established patient. It covers a health history update and an oral cancer screening, but it's not a full diagnostic workup. Most payers allow it twice a year. Bill it more often than that and you're almost guaranteed a denial or a downgrade.

D0150: Comprehensive Oral Evaluation

This is the code for a new patient's first exam, or for a returning patient who hasn't been in for years or has had a significant health change. It covers a full evaluation of hard and soft tissues, an initial periodontal assessment, and a treatment plan. Most payers only allow it once per provider, per patient, so billing it again too soon is one of the fastest ways to trigger a claim review.

Why the distinction matters

Bill D0150 for a routine six-month recall, or D0120 for a patient's very first exam at your practice, and you're inviting a downgrade or a records request. Get in the habit of using the right code every time, and make sure your chart notes actually support which exam was performed. That habit protects your practice if a payer ever comes asking for records.