White Fillings on Back Teeth: Cost, Lifespan and Downgrade Clauses
A posterior composite is a bonded tooth-coloured filling in a back tooth. It has become the default restoration in most practices: the material bonds to the tooth, so less healthy structure has to be removed than amalgam required, and it looks like a tooth rather than a repair.
What composite restoration, posterior tooth involves
A posterior composite is a bonded tooth-coloured filling in a back tooth. It has become the default restoration in most practices: the material bonds to the tooth, so less healthy structure has to be removed than amalgam required, and it looks like a tooth rather than a repair. Placing one well is technically demanding in a way amalgam was not. Composite shrinks very slightly as it cures, which puts stress on the bond, so it is built up in increments rather than packed in one mass. It also needs a genuinely dry field — contamination by saliva or blood compromises the bond — which on a lower second molar with a deep box means rubber dam or very careful isolation.
When this treatment is used
Used for decay, fractures and failed previous restorations on premolars and molars. Also used to replace old amalgams that have cracked, leaked or developed decay at the margins.
The downgrade clause, and how to plan around it
This is the code most affected by the alternate benefit provision. A large number of dental plans state that for posterior teeth they will pay the allowance for an amalgam restoration; if a composite is placed, the patient pays the difference. On a three-surface molar filling that difference is often substantial. It is legal, it is in the policy document, and it is not something the dental office can override. What you can do is ask for a pre-treatment estimate before treatment so the number is known in advance, and ask whether an amalgam is a reasonable clinical option for that particular tooth. Sometimes it is. On a tooth with thin remaining walls it genuinely is not, because the bonded material helps hold the tooth together and amalgam does not.
Sensitivity after placement
Mild sensitivity to cold or to biting for a few weeks after a deep posterior composite is common and usually settles. It comes from the bonding process and from the proximity of the preparation to the nerve. Sensitivity that gets worse rather than better, that lingers for many seconds after cold, or that wakes you at night is different — that suggests the pulp is irreversibly inflamed and needs assessment. A sharp pain only on biting in one specific spot often means the filling is very slightly high and needs a minute of adjustment. That is worth going back for rather than waiting out.
Costs and insurance in summary
Typical fee range across the group: $0–$0 where a single band applies. Several codes here are priced individually and carry their own range on their own page. Priced by surface count. Plans that apply an alternate benefit will pay only the amalgam allowance, leaving the difference to the patient.
Benefit category: Basic, 70–80% of the amalgam allowance on many plans on a typical plan. Covered as basic restorative work, but this is the classic downgrade code — many plans pay only what an amalgam would have cost.
Common restrictions: Alternate benefit clauses commonly apply to posterior teeth; Usually not payable again on the same surface within 24 months; Four-surface restorations may prompt a request for images or a crown recommendation.
The codes this guide covers
Each of these describes a variant of the same procedure. Follow a code for its own fee range, its coverage notes and what distinguishes it from the rest of the group.
| Code | Variant | Typical fee |
|---|---|---|
| D2391 | Composite filling — one surface, posterior | $150–$350 |
| D2392 | Composite filling — two surfaces, posterior — most reported | $195–$455 |
| D2393 | Composite filling — three surfaces, posterior | $240–$560 |
| D2394 | Composite filling — 4+ surfaces, posterior | $285–$665 |
Common questions
Why did my insurance only pay part of my white filling?
Most likely an alternate benefit clause: the plan pays the amalgam allowance for back teeth and you pay the difference for composite. Asking for a pre-treatment estimate in advance avoids the surprise.
How long do white fillings last on back teeth?
Typically seven to twelve years. Larger restorations and patients who grind their teeth are at the shorter end.
Why is my new filling sensitive?
Mild cold or biting sensitivity for a few weeks is common and usually settles. Pain that worsens, lingers, or wakes you at night needs reassessment, and a sharp pain only when biting often just means the filling needs adjusting.
Is a filling or a crown better for a large cavity?
Once a restoration is rebuilding most of the biting surface and the remaining walls are thin, a crown or onlay protects the tooth better. A very large filling in a weakened molar has a real risk of the tooth fracturing.