Dental insurance glossary: plain-English terms

Dental plans use their own vocabulary, and it decides what you actually pay. Here are 41 common terms in plain English. Your plan's own documents (the schedule of benefits or summary of benefits) always take precedence over general definitions.

100/80/50 coverage: Shorthand for a common way plans split costs: many plans pay 100% for preventive care, 80% for basic and 50% for major services, after any deductible (source: Humana). Your own plan's percentages may differ.
Allowed amount: The most the plan will count for a covered service. Your coinsurance is calculated on this amount, not necessarily on the dentist's full fee.
Annual maximum: The most your dental plan will pay toward your care in one benefit year. Once the plan has paid that amount, you pay the full cost of anything else until the year resets. It is often the biggest limit on what a plan is worth if you need a lot of work.
Assignment of benefits: Your permission for the plan to pay the dentist directly instead of paying you.
Balance billing: When an out-of-network dentist bills you for the difference between their fee and what your plan allows. In-network dentists generally agree not to do this.
Basic services (Class II): Treatment for common problems, such as fillings and simple extractions. Some plans also put root canals or gum treatment here, others in major.
Benefit year: The 12-month period your deductible and annual maximum apply to. It may be the calendar year or start on another date, such as your plan's renewal date.
CDT codes: Standard procedure codes from the American Dental Association's Code on Dental Procedures and Nomenclature, used on claims. Each code starts with "D", such as a code for a routine exam or a crown. (ADA: CDT Code)
Claim: The request for payment that your dentist (or you) sends to the plan after treatment.
Coinsurance: Your share of the cost of a covered service, shown as a percentage, after any deductible. If the plan pays 80% of the allowed amount, your coinsurance is the other 20%.
Coordination of benefits (COB): Rules that decide which plan pays first when you have coverage from two plans, so the two together don't pay more than the total cost.
Copay (copayment): A set dollar amount you pay for a specific service, instead of a percentage. Copays are common in DHMO plans, where each procedure has a listed fee.
Deductible: The amount you pay yourself each benefit year before the plan starts sharing costs. Many dental plans do not apply the deductible to preventive care such as checkups and cleanings — check your plan's summary.
Dental discount plan: Not insurance. You pay a membership fee and get reduced prices at participating offices; you pay the discounted fee yourself, and there is no claim or annual maximum. See our insurance vs. discount plans guide.
Dependent: A family member, such as a spouse or child, covered under your plan. Plans set their own age and eligibility rules for dependent children.
DHMO (dental HMO): A plan where you choose a primary dentist from the network and pay set copays for listed services. Care outside the network is usually not covered, and specialist visits may need a referral.
Downgrade (alternate benefit): When the plan pays only for a cheaper option than the one you chose — for example paying a silver-filling rate for a tooth-colored filling. You pay the difference.
Eligibility: Whether you are covered on the date of service. Dental offices often check eligibility before an appointment.
Exclusion: A service the plan does not cover at all, such as purely cosmetic treatment on many plans. Check the exclusions list in your plan documents.
Explanation of benefits (EOB): A statement from your plan after a claim showing what the dentist charged, what the plan allowed and paid, and what you owe. It is not a bill.
Frequency limitation: A limit on how often the plan pays for a service, such as a set number of cleanings per year or one set of certain X-rays within a period of years.
In-network: Dentists who have a contract with your plan and agree to its negotiated fees. Seeing them usually costs you less.
Indemnity plan (fee-for-service): A traditional plan that lets you see any dentist and pays a share of the cost, often based on UCR fees. You may pay up front and file a claim for reimbursement.
Least expensive alternative treatment (LEAT): The plan rule behind downgrades: it pays based on the least costly treatment it considers acceptable, even if you and your dentist choose another.
Major services (Class III): More complex work, such as crowns, bridges and dentures (and implants on plans that cover them). Plans usually pay the lowest share for this class.
Medicaid dental benefits: Dental coverage through your state's Medicaid program. Children's dental benefits are required; adult benefits vary by state. See our Medicaid dentist guide and official state finder links.
Medicare and dental: Original Medicare generally doesn't cover routine dental care such as cleanings, fillings or dentures; some Medicare Advantage plans add dental benefits (Medicare.gov).
Missing tooth clause: A rule that the plan won't pay to replace a tooth (for example with a bridge or implant) if it was already missing before your coverage began.
Orthodontic lifetime maximum: A separate cap on what a plan will ever pay for braces or aligners for one person, if it covers orthodontics. It is usually separate from the annual maximum.
Out-of-network: Dentists without a contract with your plan. Depending on the plan, you may get lower coverage, owe balance billing, or get no coverage at all (as with most DHMOs).
Out-of-pocket cost: Everything you pay yourself: deductible, coinsurance or copays, anything above the annual maximum, and services the plan doesn't cover.
PPO (preferred provider organization): A plan with a network of dentists at negotiated fees. You can usually also see dentists outside the network, but often pay more.
Pre-authorization: Approval the plan requires before you get certain treatment for it to be covered. Without it, the plan may refuse to pay.
Pre-existing condition (dental): A dental problem you had before joining the plan. Some dental plans limit coverage for it — the missing tooth clause is the most common example.
Predetermination (pre-treatment estimate): Your dentist sends the treatment plan to the insurer first, and the insurer replies with what it expects to pay. It is an estimate, not a guarantee — eligibility and remaining benefits are checked again when the claim is filed.
Premium: What you or your employer pay each month to keep the plan active, whether or not you use it.
Preventive services (Class I): Care meant to prevent problems — typically exams, cleanings and routine X-rays. Plans usually cover this class at the highest level.
Primary and secondary plan: Under coordination of benefits, the primary plan pays first; the secondary may then pay some of what is left, according to its own rules.
Schedule of benefits: The document that lists what your plan covers, how each service is classified, and what share the plan pays. It is the final word on your coverage.
UCR (usual, customary and reasonable): The fee level a plan considers normal for a procedure in your area. Some plans base their payment on UCR; if your dentist charges more, you may owe the difference.
Waiting period: Time you must be enrolled before the plan covers certain services. Preventive care often has no wait; basic and major work, such as crowns, may have a waiting period, especially on individual plans.

Sources

Definitions are our own plain-English wording, checked against: HealthCare.gov glossary (deductible, coinsurance, copayment, preauthorization, coordination of benefits), ADA – CDT Code, Medicare.gov – Dental services and Humana – How does dental insurance work? (100/80/50). Links checked October 29, 2026.