Co-insurance is the percentage of a covered dental procedure’s approved cost that a patient is responsible for paying after the plan’s deductible has been satisfied. Unlike a fixed copayment, co-insurance is calculated as a percentage, meaning the patient’s share scales proportionally with the total allowed fee for the service.
How Co-insurance Works
Most dental benefit plans divide covered services into tiers — typically preventive, basic, and major — each carrying its own co-insurance rate. Once the annual deductible is met, the insurer pays its contracted share and the patient owes the remainder, up to the plan’s annual maximum.
For example, if a plan covers basic restorative services at an 80/20 split, the plan pays 80 percent of the allowed fee for a composite filling and the patient pays 20 percent. If the allowed fee is $200, the patient’s co-insurance obligation is $40.
Typical Co-insurance Rates by Service Category
- Preventive services (exams, prophylaxis, radiographs): 100 percent plan coverage, zero patient co-insurance in most plans
- Basic restorative services (fillings, simple extractions): commonly 70–80 percent plan, 20–30 percent patient
- Major restorative services (crowns, bridges, endodontic treatment): commonly 50 percent plan, 50 percent patient
- Periodontal procedures (scaling and root planing): classified as basic or major depending on the plan, with co-insurance rates varying accordingly
- Orthodontic treatment: often covered at a fixed lifetime benefit with a separate co-insurance percentage, when included at all
Why Co-insurance Matters for Treatment Planning
Understanding co-insurance rates helps both patients and dental teams set accurate financial expectations before treatment begins. A patient accustomed to full-coverage preventive visits may be surprised to learn that a recommended crown falls under the major services tier with a 50 percent co-insurance requirement. Submitting a predetermination to the insurer before scheduling major procedures gives patients a reliable estimate of their actual out-of-pocket cost and reduces post-treatment billing disputes.
Co-insurance also interacts directly with the plan’s annual maximum — the ceiling on what the insurer will pay within a given benefit year. Once that maximum is exhausted, the patient assumes 100 percent of remaining costs regardless of the co-insurance schedule.
Reviewing co-insurance rates alongside deductibles, waiting periods, and annual maximums before selecting a dental plan or scheduling elective procedures is the most reliable way for patients to avoid unexpected costs and for clinicians to present complete, financially transparent treatment options.