What’s the correct CDT procedure code for desiccation therapy?

Desiccation therapy is changing the way hygienists treat periodontal diseases. Nonsurgical periodontal therapy (scaling and root planing), whether performed with hand or power instruments, does not fully eliminate pathogenic microbes within diseased subgingival pockets and surrounding tissues.

When desiccation therapy is included during SRP, the procedure disrupts and destroys all pathogenic microbes and the extracellular polysaccharide biofilm matrix.

How desiccation therapy works

Dental desiccation agents, such as PerioDT (Young Specialties) and HybenX (Epien Medical Products), contain an aqueous mixture of sulfonated phenolics and sulfuric acid. When applied to inflamed periodontal pockets, the agent rapidly removes water from the biofilm and necrotic tissue. This chemical dehydration process produces several clinical benefits: 

• Destroys biofilm: It dehydrates the water-rich biofilm matrix and kills microorganisms within it.
• Enhances calculus removal: It draws moisture from plaque and calculus deposits, causing them to shrink and crumble and making removal easier from teeth and prosthetic surfaces.
• Reduces bleeding: The cauterizing effect controls bleeding from inflamed tissue, giving the clinician a clearer field of view.
• Promotes healing: By eliminating pathogens and necrotic tissue, the desiccant creates a clean surface for tissue reattachment and healing.

Dental coding considerations

Currently, there is no CDT procedure code that specifically describes this adjunctive therapy. However, each service category includes an “unspecified _____ procedure, by report” code (ending in 999) that may be used when no existing code applies.

Examples:

• Adult prophylaxis (D1110): If desiccation therapy is used to disrupt biofilm and aid in calculus removal (e.g., veneer-type calculus, pipe stain, hard deposits), report D1999.
• Scaling in the presence of generalized moderate or severe gingival inflammation (D4346): If desiccation therapy assists in destroying biofilm and necrotic tissue, report D4999.
• Scaling and root planing (D4341/D4342): If desiccation therapy aids in pathogen elimination, necrotic tissues, and calculus removal, report D4999.

Why not select CDT procedure code D4381 or D4921?

When desiccation products were first introduced, there was confusion regarding which CDT procedure codes applied. Some codes were incorrectly suggested (based on their descriptors), but they are not appropriate.

D4381 localized delivery of antimicrobial agents via a controlled release vehicle into diseased crevicular tissue, per tooth.

Descriptor: FDA-approved subgingival delivery devices containing antimicrobial medication(s) are inserted into periodontal pockets to suppress the pathogenic microbiota. These devices slowly release pharmacological agents so they can remain at the intended site of action in a therapeutic concentration for a sufficient length of time (p. 35, CDT 2025).

• These products are a “fast adjunctive debridement of pathogenic biofilm at the molecular level.” Therefore, their main purpose is for “debridement” with a side benefit of select antimicrobial properties.
• It is NOT delivered “via a controlled release vehicle.” What is the “vehicle”? The rate of desiccation (called “fast adjunctive debridement of pathogenic biofilm”) is not a “controlled release.”
• How is this product a “subgingival delivery device” that “slowly releases the pharmacological agents” in a “therapeutic concentration for a sufficient length of time”? These products begin to desiccate calculus quickly within one minute.

D4921 gingival irrigation—per quadrant

Descriptor prior to CDT 2023: Irrigation of gingival pockets with medicinal agent. Not to be used to report use of mouth rinses or noninvasive chemical debridement.

Descriptor beginning in CDT 2023: None (p. 35, CDT 2025).

The medical definition of “irrigation” (from Taber’s Cyclopedic Medical Dictionary) states: “The cleansing of a canal or cavity or the washing of a wound by flushing water or fluid.” This does not describe the action of these products.

Calculus softeners

Products such as SofScale (Dentsply Sirona) and Turbo-CR (Essential Dental Systems/EDS) are sometimes mistaken for desiccants. They are not.

• SofScale: This is marketed as a calculus softener but was ultimately found less effective. Contains ingredients flagged under California’s Proposition 65 for reproductive risks.
• Turbo-CR: This uses chelating agents, detergents, and mild abrasives to speed calculus removal. Its chemistry is entirely different from desiccation products.

Because CDT procedure codes describe procedures rather than products, there is no specific CDT code for using calculus softeners.

The key takeaway

Hygienists must use discernment when coding for new products or procedures. They should always consult the current CDT manual, read descriptors carefully, and ensure the recommended procedure code accurately reflects the procedure performed.