When it comes to CDT codes, many dentists tend to have the same questions: How is this different from other similar codes? Can I report this procedure on the same date of service as other procedures?

In an effort to help clear up these questions and explain new codes that may be unfamiliar to dentists, below are six codes dentists should know and details about how to use them.

D0150 comprehensive oral evaluation — new or established patient
The ADA frequently receives questions from members about this commonly used code, particularly about how it differs from codes D0120 periodic oral evaluation and D0180 comprehensive periodontal evaluation. Code D0150 is used for new patients, established patients who have experienced a significant change in health conditions or established patients who have been absent from active treatment for three or more years. On the other hand, code D0120 is used for established patients returning to determine any changes in their dental and medical health status since a previous comprehensive or periodic evaluation, and code D0180 is used for new or established patients returning for treatment who show signs or symptoms of periodontal disease.

D2940 placement of interim direct restoration
The nomenclature for this code was revised in CDT 2025 from "protective restoration" to "placement of interim direct restoration.” This revision is related to the deletion of code D2941 interim therapeutic restoration — primary dentition. These actions together were made to simplify the documentation and reporting of interim restorations. Based on its revised descriptor, code D2940 now serves as a single code to capture the placement of any restorative material as an interim direct restoration using any method as long as the delivering provider is acting within their scope of licensure.

D2956 removal of an indirect restoration on a natural tooth
Also new in 2025 is this code for a crown removal procedure. The code does not specify the method of or reason for removal, but it cannot be used for the removal of a temporary or provisional restoration.

D4355 full mouth debridement to enable a comprehensive periodontal evaluation and diagnosis on a subsequent visit
This is another code that often elicits questions, specifically about whether or not it can be reported on the same date of service as other procedure codes. For example, it can be reported on the same date as code D0120 periodic oral evaluation or code D0150 comprehensive oral evaluation, but it cannot be reported on the same date as D0180 comprehensive periodontal evaluation. Also, because the purpose of code D4355 full mouth debridement is to enable the dentist to complete the comprehensive periodontal evaluation, it cannot be reported at a second visit after the evaluation was already completed at the initial visit.

D6089 accessing and retorquing loose implant screw — per screw and D6193 replacement of an implant screw
Code D6089 was new in CDT 2024, and code D6193 is new in CDT 2025. Here’s an example of how to use them from the CDT 2025 Coding Companion: If a dentist is completing a D0120 periodic oral evaluation and finds an implant-supported crown is loose and the screw needs to be retorqued, that procedure would be coded separately from the periodic evaluation as code D6089. If the dentist determines the implant screw cannot be retorqued and instead needs to be replaced, the procedure code would be D6193.

Full entries for all CDT codes, including their nomenclatures and descriptors, are published annually. The 2025 update includes 24 total changes: 10 new codes, eight revisions, two deletions and four editorial changes. Staying updated with CDT codes from each version is crucial for dental practice efficiency, compliance and patient care.

CDT 2025: Current Dental Terminology and the CDT 2025 Coding Companion are available for purchase from the ADA Store. The ADA website also offers coding education guides to help dentists understand coding scenarios. Any coding questions can be directed to dentalcode@ada.org or the ADA Member Service Center at 1-800-621-8900.