What is coinsurance?
Coinsurance is the percentage of a covered dental procedure's cost that you and your insurance plan each pay, calculated after your deductible has been satisfied. In dental PPO plans, coinsurance is expressed as the plan's share — a '100/80/50' structure means the plan pays 100% of preventive, 80% of basic services, and 50% of major services. Your share is the inverse: 0% / 20% / 50% respectively. Critically, coinsurance is always calculated against the lower of the dentist's actual charge or the plan's allowed amount (UCR fee) — not against the full billed amount if that amount exceeds the plan's limit.
How it works
After you meet your deductible, each claim is split according to the plan's coinsurance schedule. The plan determines the applicable service category (preventive, basic, major), looks up the CDT code, compares the provider's charge against the plan's UCR or negotiated rate, applies the plan's percentage to the lower amount, and pays that portion. You are billed for the remainder — your coinsurance share plus any balance billing if out-of-network.
Crown needed. In-network dentist, negotiated rate $900. Major services covered at 50%. You have met your deductible. Plan pays: 50% × $900 = $450. You pay: $450. Total: $900. Same crown, out-of-network dentist charges $1,300. Plan's UCR for this procedure in this zip code: $1,000. Plan pays 50% × $1,000 = $500. You owe: 50% × $1,000 = $500 coinsurance + $300 balance bill = $800 total.
What to watch out for
- Coinsurance and the deductible are separate and stack. Meeting your deductible does not end your obligation — you still pay your coinsurance percentage on every subsequent claim.
- Out-of-network dentists can trigger balance billing on top of coinsurance. The plan's coinsurance applies to UCR, not the dentist's full charge. The gap between the dentist's charge and UCR is 100% your responsibility, on top of your coinsurance share.
Frequently asked questions about coinsurance
80/20 typically refers to basic service coinsurance — the plan pays 80% of the allowed amount and you pay 20%. Full dental plans usually express three coinsurance tiers: 100% preventive / 80% basic / 50% major. The percentages represent the plan's share, so '50% major' means you also pay 50%.
After. You pay the full deductible first. Once the deductible is met, coinsurance applies to the remaining allowed amount. On a $200 filling with a $50 deductible and 80/20 plan: you pay $50 + 20% of $150 = $80 total. The plan pays $120.
No — your coinsurance payments do not count toward the annual maximum. Only what the plan pays counts. If you pay $500 in coinsurance on various procedures, that $500 is yours. The plan's $500 in payments counts toward the maximum.
Some plans offer improving coinsurance over years of continuous enrollment — for example, 50% major coverage in Year 1 stepping up to 70% in Year 3. This is called a 'graded' or 'step-up' coinsurance structure. Check your plan's benefit schedule or Summary of Benefits for any step-up provisions.
Find a dentist who accepts your PPO
Search CoverCapy's verified network of accredited PPO dentists and confirm your coverage before you arrive.
Search PPO dentists near meFree verification · No account required