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Composite restorations make up a substantial volume of procedures in general dentistry. Selecting the right code based on tooth location and surface count determines whether you receive appropriate reimbursement. D2391 specifically addresses single-surface posterior composites, yet many practices mistakenly interchange it with similar codes. This article explains exactly when D2391 is the correct choice, what records you need to maintain, and which pitfalls to sidestep during billing. Understanding these details protects your practice from underpayment while keeping your operatory schedule flowing without interruption.
Nov 1, 2025
What is Dental Code D2391?
D2391 represents a resin-based composite restoration on one surface of a posterior tooth. The code covers tooth-colored filling material placed on molars or premolars when decay or damage affects only a single surface. Treatment includes cavity preparation, placement of composite material, and finishing of the restoration.
This code specifically applies to posterior teeth, which include all premolars and molars. The restoration must involve exactly one surface—either occlusal, buccal, or lingual. Multiple surfaces on the same tooth require different codes based on the number of surfaces restored.
Common Terminology
Familiarity with these terms helps clarify when D2391 is appropriate:
Resin-based composite: Tooth-colored filling material made from plastic resin and filler particles that bonds directly to tooth structure
Posterior teeth: Premolars and molars located in the back of the mouth, typically teeth #2-5, #12-15, #18-21, and #28-31
Single surface: A restoration affecting only one side of the tooth, such as the chewing surface or a side wall
Occlusal surface: The top chewing surface of posterior teeth where most cavities develop
Direct restoration: A filling placed and shaped in the mouth during a single appointment, as opposed to lab-fabricated restorations
When is D2391 Used?
You'll select D2391 when restoring a single surface on a posterior tooth with composite material. The decay or defect must be limited to one surface without extending into adjacent areas. Location and surface count are the two critical factors in choosing this code correctly.
Common Clinical Scenarios
D2391 fits these treatment situations:
Small occlusal cavities on molars or premolars that haven't spread to adjacent surfaces
Buccal or lingual surface decay on posterior teeth that affects only the outer or inner wall
Replacement of failed amalgam or composite restorations that originally involved one surface
Repair of minor fractures or chips affecting a single surface of a posterior tooth
Class V lesions on the facial or lingual surfaces of premolars or molars near the gum line
Abrasion or erosion defects on one surface that require restoration to prevent further damage
When D2391 is NOT Appropriate
Different codes become necessary in these circumstances:
Two-surface posterior composites should use D2392 instead of D2391
Three-surface posterior composites fall under D2393, regardless of which surfaces are involved
Four or more surface posterior composites require D2394 for correct billing
Anterior tooth composites need codes D2330-D2335 based on surface count and tooth location
Preventive resin restorations on occlusal pits and fissures call for D1351, not D2391
Composite buildups for crown preparations use D2949 rather than restoration codes
Billing and Insurance Considerations
Accurate coding for D2391 relies on precise surface counting and proper tooth identification. Insurers review composite claims carefully due to frequent coding errors. Maintaining thorough documentation reduces disputes and accelerates payment processing.
Documentation Requirements
Clinical records must validate your code selection:
Examination notes describing the location and extent of decay or damage on the specific tooth
Surface notation clearly stating which single surface received the composite restoration
Charting that shows the tooth number and affected surface using standard dental notation
Treatment notes explaining material selection and any special considerations during placement
Post-operative documentation confirming the restoration was completed and adjusted for proper occlusion
Radiographic documentation adds supporting evidence:
Bitewing radiographs showing the depth and location of interproximal decay if applicable
Pre-treatment images establishing the baseline condition and justifying the restoration
Post-treatment radiographs demonstrating proper restoration contours and margins when clinically indicated
Comparative images showing changes from previous radiographs if replacing an existing restoration
Insurance Coverage
Reimbursement for D2391 depends on plan specifics and policy terms:
Standard dental plans typically cover posterior composites at 80% after deductibles as part of basic restorative care
Some plans distinguish between amalgam and composite materials, paying composites at a lower rate or only covering amalgam equivalent costs
Replacement frequency limitations commonly restrict coverage to one restoration per surface every two to five years
Plans may deny coverage for composite replacements done primarily for aesthetic improvements rather than functional necessity
Documentation must establish clinical need rather than patient preference when plans have material restrictions
Common Billing Mistakes
Watch for these frequent errors that trigger payment problems:
Miscounting surfaces and billing D2391 when the restoration actually extends to two or more surfaces
Using D2391 for anterior teeth instead of the appropriate D2330 series codes
Billing composite replacements within the frequency limitation window without explaining why early replacement was clinically necessary
Failing to distinguish between preventive sealants (D1351) and actual restorations (D2391) on occlusal surfaces
Submitting claims without clear tooth number identification or surface specification
Using D2391 for composite buildups or other procedures that have specific codes outside the restoration series
Common Questions
How often can I bill D2391 on the same tooth surface?
Insurance plans generally permit one restoration per surface every two to five years, depending on the carrier. Billing sooner requires documentation showing the previous restoration failed due to recurrent decay, fracture, or other clinical problems. Include photographs or detailed notes explaining the failure mode. Some plans won't cover repeated restorations on the same surface regardless of clinical need within their specified timeframe.
What's the difference between D1351 and D2391?
D1351 covers preventive resin restorations applied to sound tooth structure to seal pits and fissures. D2391 involves removing decay and restoring damaged tooth structure with composite material. The key distinction is whether you're preventing future decay or treating existing disease. If you remove carious tooth structure, use D2391. If you're simply sealing susceptible anatomy, use D1351. Mixing these codes leads to claim denials.
Can I bill D2391 for a composite placed on an anterior tooth?
No. Anterior composites have separate codes in the D2330-D2335 range based on surface count. D2391 exclusively applies to posterior teeth, including premolars and molars. Using D2391 for canines or incisors constitutes incorrect coding. Anterior teeth have different reimbursement rates and coverage rules, so proper code selection matters for accurate payment.
Do I need different codes for buccal versus occlusal single-surface restorations?
No. D2391 covers any single surface on a posterior tooth, regardless of which specific surface you restore. Whether you place composite on the occlusal, buccal, lingual, mesial, or distal surface, the code remains D2391 as long as only one surface is involved. The critical factor is surface count, not surface location.
What if I restore one surface today and another surface on the same tooth next month?
Bill each restoration separately using the appropriate code for surface count at each appointment. The first appointment gets D2391 for one surface. The second appointment also uses D2391 if you restore one additional surface, or use D2392 if you're restoring two surfaces during that visit. Don't combine surfaces from different appointments into a single multi-surface code.
How do I handle insurance downgrades from composite to amalgam reimbursement?
Many plans include substitute benefit language that reimburses composite restorations at amalgam rates regardless of materials used. Review the patient's plan before treatment and discuss any additional costs they'll need to cover. Document the patient's informed consent choosing composite material with awareness of potential out-of-pocket expenses. This prevents billing disputes after treatment completion.
Can I bill D2391 if I'm replacing an existing composite for aesthetic reasons?
Insurance typically won't cover replacement of functional restorations done solely for cosmetic improvements. If the existing composite shows clinical failure such as marginal breakdown, recurrent decay, or fracture, document these findings and bill D2391. If the patient simply wants a better shade match or contour without clinical defects, the procedure becomes cosmetic and won't receive insurance coverage.
What documentation should I keep if insurance audits my D2391 claims?
Maintain comprehensive records supporting every restoration:
Detailed clinical notes describing the condition necessitating treatment on the specific tooth and surface
Pre-operative and post-operative charting showing the restoration location and extent
Radiographs demonstrating decay depth or existing restoration failure when applicable
Photographs of large or questionable lesions that might raise insurer questions
Signed treatment plans showing patient understanding of the procedure and associated costs
Progress notes from the appointment including any complications or special techniques used
Keep Your Restorative Schedule Full
High-volume restorative practices can't afford gaps in clinical coverage. Missing team members mean rescheduling production appointments or working short-handed, both of which hurt your practice financially. A single day of cancelled composite appointments adds up quickly.
Teero helps you maintain full coverage with qualified hygienists ready to work when your regular staff can't. Find professionals who understand restorative workflows and can support your busiest days. Sign up today and eliminate scheduling disruptions that cut into your productivity.