D8660 is the CDT code for a pre-orthodontic exam that monitors growth and development to decide when, or whether, to start treatment.
- When to use: The patient has no appliance yet and the dentist is watching the bite develop on a recall interval.
- When not to use: An adjustment visit during active treatment is D8670, a general comprehensive exam is D0150, and a formal consultation is D9310.
- Billing note: Many plans pay nothing for observation visits, so treat D8660 as patient responsibility until verification shows coverage or a fixed HMO copay.
What D8660 covers
D8660 reports a pre-orthodontic examination to monitor growth and development. The patient, usually a child, isn’t ready for active treatment yet. The dentist examines how the teeth, the bite, and the jaws are developing to decide when, or whether, orthodontic treatment should begin.
It is an observation and timing visit, not treatment. It typically repeats on a recall interval the dentist sets, until the time to intervene, or the decision not to, becomes clear. Typical situations:
- A child with a developing malocclusion is seen on a recall interval to watch how the bite and jaws grow before deciding whether to start braces.
- A patient is being observed after an early phase-one case, waiting for the permanent teeth to come in before a comprehensive case is planned.
Do not bill D8660 for:
- A scheduled adjustment during active treatment. That’s D8670.
- The orthodontic treatment itself. Limited treatment is coded D8010 through D8040 by dentition stage, and comprehensive treatment D8070 through D8090.
- A general comprehensive exam (D0150) or a case consultation (D9310).
D8660 versus D8670: before treatment versus during
This is the most common miscode, and the axis is timing relative to active treatment.
D8660 happens before treatment starts. Braces or aligners aren’t on. The visit exists to watch growth and decide when to begin.
D8670 happens during active treatment. The appliance is on, the case is underway, and the patient comes in for a scheduled adjustment. D8670 is often the code the continuation or installment claim is built around.
Coding D8670 before the case is banded, or D8660 once the patient is in active treatment, contradicts the treatment status the chart documents.
D8660 versus a comprehensive exam or consultation
The difference is purpose.
- A comprehensive oral evaluation (D0150) is a whole-mouth new-patient or re-evaluation exam, not specific to orthodontics.
- D8660 is narrower: a repeating look at how a malocclusion is developing, to time treatment.
- A consultation (D9310) is a diagnostic service where a dentist or specialist gives an opinion on a specific problem, often at another provider’s request. If the visit is a formal case-planning discussion rather than a growth check, a consultation code may fit better.
Coverage: observation visits are often not a benefit
The coding is straightforward; the reimbursement is not. Many dental plans pay nothing for a pre-treatment monitoring visit, because the orthodontic benefit only engages once active treatment begins. On those plans D8660 is a patient-responsibility charge, and quoting it as covered leads to a surprise bill.
Where D8660 is handled at all, the pattern varies by plan type:
- HMO or DMO plans often list a fixed patient copay for D8660. Bill the contracted amount, collect the copay, and store the copay on the plan so the estimate matches.
- PPO plans frequently treat it as non-covered or patient responsibility, since it isn’t active treatment.
- Medicaid rules are state-specific, and observation visits before a qualifying medical-necessity determination are commonly not reimbursed.
None of this is universal, so verify how the specific plan treats D8660 before the visit.
An ortho case is billed across its whole lifecycle. For how verification, the initial claim, continuation claims, and debond fit together, see the orthodontic insurance billing guide.
FAQs
- What is D8660 used for?
- D8660 reports a pre-orthodontic examination to monitor growth and development. The dentist sees a patient, usually a child, who isn't ready for active treatment and tracks how the bite and jaws develop to decide when, or whether, to start. It is billed at recall intervals the dentist sets, before any appliance goes on.
- What's the difference between D8660 and D8670?
- Timing relative to treatment. D8660 is the monitoring visit before active treatment starts. D8670 is the periodic adjustment visit during active treatment, once the appliance is on. Coding D8670 before treatment starts, or D8660 during it, puts the claim at odds with the treatment status in the chart.
- Does insurance cover D8660?
- Often not. Many plans don't reimburse observation visits, especially where the orthodontic benefit only applies once active treatment begins. Some HMO or DMO plans list a fixed copay for D8660, and on PPO plans it is frequently non-covered or patient responsibility. Verify the specific plan before the visit and set the family's expectation.
- What's the difference between D8660 and a comprehensive exam like D0150?
- Purpose. D0150 is a general comprehensive oral evaluation of the whole mouth for a new patient or a re-evaluation. D8660 is an orthodontic growth-monitoring visit to time treatment. If the visit is a formal case-planning discussion, a consultation code like D9310 may fit instead.
- How often can D8660 be billed?
- At each monitoring visit the dentist schedules, over months or years. Coverage is the constraint, not the code: a plan that reimburses D8660 may cap the frequency or the number of visits it pays. Confirm coverage and any limit before scheduling a series of observation visits.
- Is D8660 a current CDT code for 2026?
- Yes. D8660 is active in CDT 2026. It is separate from the periodic active-treatment visit (D8670) and from the limited and comprehensive treatment codes (D8010 through D8090), which report the treatment itself once it begins.
Related codes
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CDT codes are maintained by the American Dental Association. This page is an editorial billing guide, not the official ADA code descriptor. Verify current coverage policies with each carrier before submitting claims.