D2391 is for a resin-based composite (tooth-colored) filling on one surface of a posterior tooth. Posterior means premolars and molars. One surface means the filling involves only one tooth surface: occlusal, mesial, distal, buccal, or lingual. This is one of the most commonly billed codes in general dentistry.
D2391 is for a resin-based composite (tooth-colored) filling on one surface of a posterior tooth. Posterior means premolars and molars. One surface means the filling involves only one tooth surface: occlusal, mesial, distal, buccal, or lingual. This is one of the most commonly billed codes in general dentistry.
2026 CDT update: The D2391 descriptor was revised for CDT 2026. The previous language restricted D2391 to lesions penetrating into dentin. That restriction has been removed. D2391 now applies to any one-surface posterior composite regardless of lesion depth or diagnosis. D1352 (preventive resin restoration) was deleted because D2391 now covers that procedure. If your practice was billing D1352, switch to D2391.
Do NOT use D2391 for: Anterior composite fillings (use D2330-D2332). Multi-surface posterior composites (use D2392 for two surfaces, D2393 for three, D2394 for four or more). Amalgam fillings (use D2140-D2161).
Click any code to see the difference.
One surface posterior composite. Single surface involved (e.g., occlusal only).
Two surface posterior composite. Two surfaces involved (e.g., mesio-occlusal or disto-occlusal).
Many PPO plans downgrade posterior composites to amalgam reimbursement. The claim isn't denied but it's paid at the D2140 (amalgam) rate. The patient is responsible for the difference. Inform patients about downgrades before treatment so there are no billing surprises.
Billing D2392 (two surfaces) when only one surface was treated triggers an audit. Document the surfaces involved precisely. If the prep extends into a second surface, document it. If it doesn't, bill D2391.
Some plans have a waiting period or replacement limitation. If the tooth had a filling within the last 6-24 months, the replacement may be denied. Document why replacement is necessary.
Specify exactly which surface: occlusal, mesial, distal, buccal, lingual. The surface designation must match the code.
Document caries, fracture, or defective existing restoration. Reason for the filling.
Bitewing or periapical showing the caries or pathology. Not always required but supports the claim if questioned.
Resin composite. If you placed amalgam, use D2140 instead.
Delta Dental PPO commonly downgrades posterior composites to amalgam reimbursement. Delta Dental Premier plans may or may not downgrade depending on the specific plan. The reimbursement difference on a one-surface filling can be $30-60. Always check whether the patient's specific plan applies a downgrade before presenting treatment costs.
The alternate benefit clause. Payers that downgrade are using an "alternate benefit" or "least expensive alternative treatment" clause. They acknowledge that composite is an acceptable material but only pay for what they consider the least expensive clinically acceptable option. The clause is in the patient's plan documents. You can't fight it with a narrative. It's a plan design decision, not a clinical denial.
CDT 2026 impact on D2391 billing. With the deletion of D1352 and the revision of D2391's descriptor, practices that previously used D1352 for conservative resin restorations on incipient lesions should now use D2391. If your PMS still has D1352 as an active code, update it. Claims submitted with D1352 in 2026 will be denied automatically.
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Learn about our billing servicesD2391 is the CDT code for a one-surface resin composite filling on a posterior tooth (premolar or molar).
Many PPO plans reimburse posterior composites at the amalgam rate. The patient pays the difference between composite and amalgam fees.
D2391 is one surface. D2392 is two surfaces. The number of tooth surfaces involved determines the code.
Search all 206 CDT codes in our dental coding guide.