Coding is where most periodontal practices look organized on paper and disorganized in practice. The codes themselves are not the issue. The issue is what happens in the operatory when a code becomes a habit rather than a decision, and the front office starts billing what insurance will pay rather than what the chart actually supports.
In many consulting engagements I have led, the same pattern repeats. The doctor requests a full-mouth debridement for a patient who does not need it. The hygienist alternates between D4910 and D1110 because the office manager said it would help with coverage.
Kelly Tanner, PhD, RDH.
A D4346 visit gets coded as a prophy because the patient pushed back at the front desk. None of these are malicious, but all of them are documentation patterns that do not survive an audit.
Here are three coding decisions that come up in nearly every practice and how to handle each one so the chart, the code, and the conversation all tell the same story.
Stop using D4355 as the default first visit
The single most misunderstood code in hygiene is D4355, the full-mouth debridement. I hear hygienists say all the time that the doctor wants a gross debridement on a new patient when what the doctor actually wants is a thorough cleaning. Those are different procedures, and only one of them is properly coded as D4355.
Dr. Charles Blair's Coding with Confidence lays out a simple decision tree that every hygiene team should commit to memory. The question is, does gross plaque and calculus inhibit the oral evaluation? If the answer is yes, meaning the doctor literally cannot see well enough to perform a comprehensive examination, then D4355 is appropriate, and it is the only code charged that day. The patient comes back another day for the actual evaluation. If the answer is no, the appropriate oral evaluation code is charged, and treatment is selected based on the findings.
There are a few legitimate D4355 cases per year in a typical private practice, and most of those occur in rural areas or Federally Qualified Health Centers (FQHCs) where patients have not seen a dentist in many years. If a practice routinely bills D4355 for new patients without meeting the criteria, that documentation pattern will not hold up under scrutiny.
Treat D4346 as a two-visit workflow, not a one-time procedure
D4346, scaling in the presence of generalized moderate-to-severe gingival inflammation, applies when 30% or more of the mouth is bleeding, with 4-mm pockets and no bone loss.
What most practices still get wrong is the follow-through. D4346 is not a single appointment. It is the first appointment in a workflow that ends when the patient is stabilized.
At the first visit, the primary focus is education and biofilm removal. You are not chasing every speck of stain. You are getting the mouth into a non-dysbiotic state so the body can hopefully heal the inflammation, and then you schedule the patient for reevaluation in two to four weeks.
At the revisit, three outcomes are possible. The mouth has healed, and you can code that visit as D1110, the adult prophylaxis. If the mouth has not healed and biofilm is still present, the conversation shifts to home care, and you continue with another D4346. If the mouth has not healed in the absence of biofilm and the tissue still looks the same, this care still continues as another D4346.
The third scenario is the one most clinicians miss. When the home care is sound and the tissue is not responding, something systemic is likely at play. That is a patient who needs a referral to their physician before the next periodontal appointment. D4346 continues, visit after visit, until the patient is stabilized.
What changes across those years is not the code; it is the conversation, because each appointment is an opportunity to identify what is driving the persistence of inflammation and to modify risk factors through an interdisciplinary approach.
Once periodontitis is diagnosed, the code is D4910 forever
D4910, periodontal maintenance therapy, begins the day periodontitis is diagnosed and continues for the life of the patient. There is no version where the patient earns their way back to D1110 because their last visit looked healthy. You cannot un-diagnose periodontitis any more than you can un-diagnose diabetes. The disease can be in remission, but the diagnosis is permanent.
The temptation to alternate D4910 and D1110 because insurance covers prophylaxis at 100% and maintenance at 80% has been around as long as I have been practicing.
It is not creative coding. It is fraudulent coding, and it puts the practice at audit risk for marginal short-term revenue. It is also where most teams discover that their internal calibration is weaker than they thought.
The doctor diagnoses periodontitis, the hygienist codes the next visit as D4910, and the patient returns six months later. Their tissue looks healthy, and they ask the office team for a “regular cleaning.” The office team asks the hygienist, the hygienist asks the doctor, and the doctor, looking at a patient who appears stable, says it is “probably fine.” The chart now has documentation that directly contradicts the diagnosis on file.
The fix is operational. The team needs to agree that once periodontitis is diagnosed, the maintenance code remains the same. The patient education conversation has to be settled at the time of diagnosis, not relitigated at every recall, and the office team needs language to handle the patient’s question without bouncing it back to the operatory.
What defensible coding actually looks like
A periodontal coding system that survives an audit is not complicated. The chart supports the code, the code matches the diagnosis, and the team says the same thing to the patient every time, regardless of who is sitting at the front desk that day.
Use D4355 only when you genuinely cannot see well enough to evaluate. Run D4346 as the multivisit workflow it was designed to be, with a follow-up appointment built into the original treatment plan.
And once a patient has been diagnosed with periodontitis, code their maintenance visits as D4910 for the rest of their lives, even when the tissue looks beautiful. These are not aggressive coding decisions; they are accurate ones, and accurate coding is what allows a practice to be paid honestly for the care it is actually delivering.
Kelly Tanner, PhD, RDH, is a contributing author to DrBicuspid, where she shares insights and strategies to empower dental hygienists in their careers. As a leader in clinical training, professional development, and team dynamics, Tanner provides resources to help hygienists elevate their practice and personal growth. For further support, join her free Facebook group, Next Level Dental Hygiene Career and Personal Development, and explore group training and on-demand courses at www.nextleveldentalhygiene.com.
The comments and observations expressed herein do not necessarily reflect the opinions of DrBicuspid.com, nor should they be construed as an endorsement or admonishment of any particular idea, vendor, or organization. Some content may be AI-generated.
