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5 codes every dental hygienist needs to know

May 3, 2022
A popular misconception about CDT codes is that they are just for insurance claims. CDT codes are procedure codes, and every dental hygienist is responsible for using them properly as a clinician. Here are five you should know.

We all know that Current Dental Terminology (CDT) codes are part of every dental office, yet some dental professionals report never having been formally trained in coding, and are not familiar with the details.

What some may not realize, however, is that knowledge of CDT codes is not solely the responsibility of the business team. A common misconception is that the codes are “insurance codes.” Although insurance is one of the areas in which CDT codes are utilized, they are procedure codes that come from the American Dental Association (ADA). They do not come from insurance companies. The purpose of coding is to “achieve uniformity, consistency, and specificity in accurately documenting dental treatment.”1 They are also part of electronic health record laws and the HIPAA (Health Insurance Portability and Accountability Act) requirements to which we are bound.1

The reasons for and benefits of familiarity with the codes could be the topic of a separate article. For the purpose of this article, know that as clinicians and license holders, we need to understand the codes, especially those that fall under the scope of the care we provide.

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We are bound to code for the procedures we rendered. How can we ensure a nonclinical staff member will reflect what we did properly? When we understand the nomenclature that goes with each CDT code, our recommendations for treatment are less blurry. There is a lot more consistency among providers, and a lot more effective dialogue between the front and back office teams. The code is part of our record of treatment and proper documentation is part of our job.

We do not use codes or recommend treatment based on what insurance will or will not cover—this is fraud. We code for the services we performed based on the patient’s diagnosis and individual need. It is important to “inform before we perform” so that we have proper informed consent or refusal, and the patient is aware of risks, benefits, and costs before accepted treatment begins.

It is equally important to have the skills necessary to talk to our patients about why they cannot rely solely on insurance benefits when making decisions. We all know that dental insurance is not all-encompassing; it is an “assist.” It is focused mostly on preventative services with limited coverage in other areas. Coverage is not based on the patient’s individual needs and diagnoses. It is based on the way the particular plan was designed, and the less expensive the plan the patient is enrolled in, the lower the coverage.

We know if patients accept treatment solely based on what insurance will cover, they will likely be looking at more extensive and costly treatment down the road. As prevention specialists, we are on the front lines of sharing this important information.

That said, it is a good practice to know the CDT codes that fall under hygiene (radiographs, chemotherapeutics, sealants, fluoride, and the like). If you enter treatment plans, knowing some basics around restorative codes can also be helpful. Below we will look at five codes that encompass hygiene therapy (or “cleanings”).

D1110: Prophylaxis – Adult

  • Removal of plaque, calculus, and stains from the tooth structures in the permanent and transitional dentition.
  • This code is preventive in nature, but there may be generalized slight gingivitis, or localized moderate to severe gingivitis. The procedure includes scaling and polishing of all surfaces at or coronal to the cementoenamel junction (CEJ).
  • There is sometimes debate as to whether a prophy is "supra only." In health, marginal tissue is roughly 2 mm coronal to the CEJ, and sometimes there may be pseudopocketing, so a prophy is not an "above the gum" visit.

D1120: Prophylaxis – Child

  • Removal of plaque, calculus, and stains from the tooth structures in the primary and transitional dentition.
  • Prophy codes are dentition specific, but many plans are age specific.
  • Some practitioners consider moving from child status when there are no longer any deciduous teeth, but there may be other considerations like difficulty level that could support an adult prophy earlier (narratives can help).

D4346: Scaling in presence of generalized moderate or severe gingival inflammation – full mouth, after oral evaluation

  • The removal of plaque, calculus, and stains in a patient who has generalized (more than 30% of the mouth) moderate to severe inflammation (swollen, bleeding, inflamed gums, pseudopocketing). No evidence of attachment loss.
  • This code can be used in permanent, primary, or transitional dentition and there is no age limit.
  • It is therapeutic (not preventive) in nature.
  • This procedure is based on the diagnosis of generalized moderate to severe inflammation. It is not related to the level of difficulty.
  • The ADA website has a very helpful guide for understanding and reporting this code.2

D4355: Full mouth debridement to enable a comprehensive oral evaluation and diagnosis on a subsequent visit

  • This is a preliminary superficial removal of plaque and calculus.
  • This is for cases where deposits are so heavy that they interfere with the ability to do a comprehensive oral evaluation.
  • A second visit would be scheduled for an exam and diagnosis, followed by the appropriate hygiene visit(s) for definitive treatment (prophy, scaling in the presence of moderate to severe inflammation, scaling and root planing).

Periodontal scaling and root planing
D4341: 4 or more involved teeth in the quadrant
D4342: 1 to 3 involved teeth in the quadrant

  • Includes instrumentation of crown and root surfaces and is therapeutic.
  • Active periodontal disease:
  • Clinical attachment loss/4 mm or greater pocketing
  • Evidence of active disease such as bleeding, increasing pocket depths, evidence of continued attachment loss
  • Radiographic calculus is NOT a requirement
  • The code is used per quadrant.

D4910: Periodontal maintenance

  • Therapeutic procedure following periodontal therapy.
  • Follows scaling and root planing, gingival flap surgery (D4240/4241), or osseous surgery (DD4260/4261).
  • Ongoing therapy for the life of the dentition.
  • Recare intervals based on clinical evaluation.
  • In cases where the patients’ benefits may have limits around coverage for this procedure, we are still legally bound to report what we did and code as such. A helpful narrative could say that if periodontal maintenance is denied, provide the alternate benefit of a prophylaxis.
  • In cases where you have a patient presenting with a history of periodontal disease, but it is not active at the time of visit, and there is no known history of scaling and root planing, osseous or flap surgery, it is possible to use the D1110 code with the narrative that the patient received a prophy on a reduced periodontium.

This serves as a basic recap of some of the codes we use, but there are several excellent sources available to provide more detail and to help foster better dialogue between the front and back office teams. At a minimum, your office should have a current ADA CDT book. There are also other books and resources out there to help you make sense of the codes and to better incorporate accurate coding in your practice.

As health-care professionals, we have an obligation to ensure that the proper codes are reported for the procedures we render. This is a requirement for accuracy of records. As license holders, it is also in our best interest to have an understanding of the codes that fall under our scope of practice. There needs to be an understanding by both the business and clinical staff, along with a symbiotic working relationship that promotes better communication, accuracy, and efficiency across these equally important departments.

Editor's note: Originally posted in 2019 and updated regularly

1. Code on Dental Procedures and Nomenclature (CDT Code). American Dental Association website.
2. American Dental Association. A Guide to Reporting D4346. Published May 17, 2016.