What D3320 means

D3320 covers endodontic therapy (a root canal) on a premolar tooth, excluding the final restoration. "D" is dental, "33" is the root-canal-therapy endodontic group, and "20" is this premolar root canal. A root canal removes the infected, inflamed, or dead pulp, cleans and shapes the root canal system, disinfects it, and fills/seals the canal(s). This code is specifically for premolars (bicuspids) — the teeth between the canines and the molars (the first and second premolars in each quadrant). Premolars usually have one to two canals — intermediate between anterior teeth (usually one canal) and molars (usually three or more). The code excludes the final restoration (the crown or filling afterward, coded separately).

So it's a root canal on a premolar — removing the pulp, cleaning, shaping, and sealing the canal(s) — not including the restoration that follows.

The three core root canal codes are divided by tooth type: D3310 (anterior, usually one canal), D3320 (premolar, this code, usually one to two canals), and D3330 (molar, usually three or more canals). The code follows the tooth type, not the actual canal count — a premolar is D3320 even if it has an unusual number of canals. Premolar root canals are intermediate in complexity (and fee) between anterior and molar. The fee and insurance allowable for D3320 sit between D3310 (lower) and D3330 (higher), reflecting the average complexity. After the root canal, the premolar usually needs a final restoration (often a crown, since premolars bear biting forces). Coverage is under endodontic benefits (a major service); documentation supports the claim.

When it's typically used

D3320 is reported for a root canal (endodontic therapy) on a premolar (bicuspid) tooth — to treat an infected, inflamed, or dead pulp by removing it, cleaning and shaping the canal(s), and sealing them, excluding the final restoration. It's used for premolars (which usually have one to two canals), distinct from anterior (D3310) and molar (D3330) root canals.

How much does D3320 cost?

A premolar root canal is a moderate fee, often roughly 600 to 1,200 USD depending on region — intermediate between the anterior (D3310, lower) and molar (D3330, higher) root canals, reflecting the premolar's intermediate complexity (usually one to two canals). It excludes the final restoration (often a crown, separate), so the complete treatment costs more.

Is D3320 covered by insurance?

Covered under endodontic benefits, typically as a major service (a percentage after deductible), subject to the annual maximum and frequency limits (usually once per tooth per lifetime — a later retreatment uses D3347, not D3320 again). Pre-op and post-op radiographs and the diagnosis support the claim. Coding by tooth type matters (a premolar is D3320, even with an unusual canal count). The final restoration (often a crown) is coded separately. Verifying coverage helps.

Premolars and their canals

Premolars have particular anatomy, and understanding it clarifies the premolar root canal.

Premolars (bicuspids) are the teeth between the canines (front) and the molars (back) — the first and second premolars in each quadrant (typically four upper and four lower premolars). For root canals, premolars are intermediate in complexity. They usually have one to two canals — fewer than molars (which usually have three or more) but sometimes more than anterior teeth (which usually have one). For example, an upper first premolar often has two canals (two roots), while a lower second premolar often has a single canal — the number varies by which premolar and individual anatomy. So a premolar root canal may involve treating one or two canals (occasionally an unusual number), making it intermediate between the single-canal front teeth and the multi-canal molars.

This intermediate complexity is reflected in the code (D3320) and the fee (between anterior D3310 and molar D3330). The premolar root canal involves the same fundamental procedure (removing the pulp, cleaning, shaping, sealing) applied to the premolar's one or two canals. The dentist treats however many canals the premolar has. Importantly, the code is D3320 for a premolar regardless of the exact canal count (a premolar with one canal, or unusually three, is still D3320 — the code follows the tooth type). The dentist codes by the tooth being a premolar. For patients, understanding that premolars usually have one to two canals (intermediate between front teeth and molars), making the premolar root canal intermediate in complexity, clarifies the premolar root canal. It treats the premolar's canal(s). The dentist treats however many canals are present, coding by the tooth type (premolar). Understanding this helps patients see that a premolar root canal treats the premolar's one or two canals (intermediate complexity) — coded D3320 by the tooth type — applying the same root canal procedure to the premolar, with the intermediate complexity (and fee) reflecting the premolar's typical canal anatomy, between the simpler front teeth and the more complex molars.

The intermediate code

D3320 is the intermediate root canal code, and understanding this clarifies the tooth-type coding.

The three core root canal codes are tiered by tooth type and complexity: D3310 (anterior, usually one canal, the most straightforward, lowest fee), D3320 (premolar, this code, usually one to two canals, intermediate), and D3330 (molar, usually three or more canals, most complex, highest fee). So D3320 (premolar) is the intermediate code — between the anterior and molar codes in complexity and fee. This tiered structure reflects the increasing complexity (and chair time) from front to back teeth: a front tooth's single canal is the most straightforward, a premolar's one to two canals intermediate, and a molar's three-plus canals the most complex. The fees and insurance allowables follow this tiering.

The code follows the tooth type, not the actual canal count — so a premolar is D3320 even if it has an unusual canal count (e.g., a premolar with three canals is still D3320, not coded as a molar). This is important for correct coding: the dentist codes by which type of tooth it is (anterior, premolar, or molar), based on the tooth number, not by counting canals. Coding the wrong tooth type causes denials (carriers cross-reference the tooth number with the code — a premolar tooth number must have D3320). So D3320 is used specifically for premolars. The dentist uses the code matching the tooth type. For patients, understanding that D3320 is the intermediate root canal code (premolar, between anterior D3310 and molar D3330 in complexity and fee), with the code following the tooth type, clarifies the coding. D3320 is for premolars specifically. The dentist codes by the tooth type. Understanding this helps patients see that a premolar root canal is coded D3320 — the intermediate code reflecting the premolar's intermediate complexity (between front teeth and molars) — with the code following the tooth type (premolar), so the premolar root canal is coded and priced according to its tooth type, between the simpler anterior and the more complex molar root canals.

Premolars usually need a crown after

A premolar often needs a crown after a root canal, and understanding why clarifies the complete treatment.

After a root canal, a tooth needs a final restoration (the root canal code excludes it). For premolars, the final restoration is often a crown. The reason: premolars are back-ish teeth that bear significant biting and chewing forces (more than front teeth), and a root-canal-treated tooth can be more brittle (having lost the pulp and often significant structure from the decay/access). So premolars (and molars) commonly need a crown after a root canal — to protect the tooth from fracture under biting forces and restore its function. The crown covers and protects the treated tooth, reducing the risk of it cracking (a root-canal-treated back tooth without a crown is more prone to fracture). So a premolar root canal is usually followed by a crown (especially if the tooth has significant structure loss).

That said, it depends on the tooth's condition — a premolar with conservative access and minimal prior restoration might sometimes be restored with a direct restoration (filling), though this is less common than for front teeth (premolars more often needing crowns due to the biting forces). The dentist assesses and usually recommends a crown for a root-canal-treated premolar (for protection). So the complete treatment is the root canal (D3320) plus the final restoration (often a crown, coded separately, e.g., D2740 or D2750), making the complete cost more than the root canal alone. The dentist plans the root canal and the appropriate restoration (often a crown). For patients, understanding that a premolar usually needs a crown after a root canal — to protect the tooth from fracture under biting forces — clarifies the complete treatment. The root canal treats the pulp; the crown protects the tooth. The dentist usually recommends a crown for a treated premolar. Understanding this helps patients see that a premolar root canal is usually followed by a crown (for protection against fracture, given the biting forces on back teeth) — so the complete treatment is the root canal plus a crown (coded separately) — and the complete cost includes both, fully treating and protecting the premolar (which, having had the root canal, benefits from the crown's protection to function long-term).

Root canal vs retreatment for a premolar

A premolar root canal differs from a retreatment, and understanding the distinction clarifies the coding.

There's an important distinction between an initial root canal and a retreatment. D3320 is for an initial root canal on a premolar that hasn't had one before — treating the pulp for the first time. If a premolar that already had a root canal needs the root canal redone (because the previous one failed — e.g., persistent infection, reinfection, or an inadequate prior treatment), that's a retreatment, coded D3347 (retreatment of previous root canal therapy, premolar) — not D3320 again. So an initial premolar root canal is D3320, while redoing a previously-root-canaled premolar is D3347.

This distinction matters for correct coding and for insurance. Insurance typically covers an initial root canal (D3320) once per tooth (per lifetime), so billing D3320 again on a tooth that already had a root canal would be denied (a frequency-limit denial) — the retreatment code (D3347) is used instead. Also, carriers can see the prior root canal on the pre-op X-ray (the existing fill), so coding a retreatment as an initial root canal (D3320 on an already-treated tooth) gets caught on audit. So the dentist checks whether the tooth already had a root canal (via the X-ray/history) and codes accordingly — D3320 for an initial root canal, D3347 for a retreatment. The dentist uses the correct code based on whether it's an initial treatment or a retreatment. For patients, understanding that an initial premolar root canal (D3320) differs from a retreatment (D3347, for redoing a previously-treated premolar) clarifies the coding. The initial treatment is D3320; redoing a prior root canal is D3347. The dentist codes by whether the tooth had a prior root canal. Understanding this helps patients see that a first-time premolar root canal is D3320, while redoing a previously-root-canaled premolar (a retreatment) is D3347 — so the code depends on whether the tooth has had a root canal before, with the retreatment having its own code (and its own coverage considerations), distinct from the initial root canal.

Frequently asked questions

What is the D3320 dental code?

It's a root canal (endodontic therapy) on a premolar (bicuspid) tooth — removing the infected or inflamed pulp, cleaning and shaping the canal(s), and sealing them. Premolars usually have one to two canals (intermediate complexity). It excludes the final restoration (coded separately).

How many canals does a premolar have?

Usually one to two — intermediate between front teeth (usually one) and molars (usually three or more). For example, an upper first premolar often has two canals, while a lower second premolar often has one. The code is D3320 regardless of the exact count (it follows the tooth type).

Why is D3320 the intermediate code?

The root canal codes are tiered by tooth type and complexity: D3310 (anterior, one canal, lowest fee), D3320 (premolar, one to two canals, intermediate), D3330 (molar, three or more canals, highest fee). D3320 sits in the middle, reflecting the premolar's intermediate complexity.

Does a premolar need a crown after a root canal?

Usually yes — premolars bear significant biting forces, and a root-canal-treated tooth can be more brittle, so a crown protects it from fracture. A premolar with very conservative access might occasionally take a filling, but crowns are common for treated premolars. The crown is coded separately.

How much does a premolar root canal cost?

Often around 600 to 1,200 USD, intermediate between the anterior (lower) and molar (higher) root canals, reflecting the premolar's intermediate complexity. It excludes the final restoration (often a crown, separate), so the complete treatment costs more.

What if a premolar root canal needs redoing?

That's a retreatment, coded D3347 (retreatment of previous root canal therapy, premolar) — not D3320 again. D3320 is for an initial root canal; redoing a previously-treated premolar uses D3347. Billing D3320 again on an already-treated tooth would be denied.

This page is an independent, plain-language explanation for general information only. It is not billing, coding, or clinical advice. For the official CDT descriptor and current-year wording, refer to the American Dental Association.