Coinsurance

Coinsurance is the patient's share of the cost for a covered dental service, expressed as a percentage of the allowed amount rather than a fixed dollar figure. After the patient has satisfied their annual deductible, the insurance plan pays its designated percentage and the patient is responsible for the remaining coinsurance portion. The most common coinsurance structure in dental PPO plans is the 100/80/50 model, where preventive services are covered at 100 percent, basic services at 80 percent with the patient paying 20 percent coinsurance, and major services at 50 percent with the patient paying 50 percent coinsurance. Some plans use different splits such as 100/70/50 or 80/60/50.

Coinsurance is always calculated on the allowed amount, not on the dentist's standard fee. For in-network providers, the allowed amount is the contracted rate established in the provider agreement. For out-of-network providers, the allowed amount is determined by the plan's UCR schedule or a percentile of prevailing fees. This distinction is important for patient cost estimates because the coinsurance percentage is applied to the payer-determined amount, and any balance above the allowed amount may be billed to the patient separately as a non-covered charge, depending on network status and plan provisions.

Understanding and communicating coinsurance accurately is fundamental to dental revenue cycle management. Billing teams must know each patient's coinsurance percentages by benefit category to generate reliable cost estimates, collect appropriate amounts at the time of service, and avoid post-treatment balance adjustments. Plans with non-standard coinsurance structures require particular attention, as assumptions based on the common 100/80/50 model can lead to incorrect estimates. Practices that verify coinsurance rates during eligibility checks and apply them correctly in patient estimates experience higher point-of-service collections and fewer billing disputes.