Short answer: Compare the annual maximum, the coinsurance for preventive/basic/major services, any waiting periods, orthodontia coverage, the network, and how out-of-network claims are paid (MAC vs. R&C).
When evaluating a dental plan, weigh several features: the annual benefit maximum (the most the plan pays per year), the coinsurance tiers (commonly 100% preventive, 80% basic, 50% major), any waiting periods before major services are covered, whether orthodontia is included and its lifetime maximum, the size of the provider network, and the out-of-network reimbursement method. Plans that reimburse out-of-network on a ‘reasonable and customary’ basis usually leave smaller balances than ‘maximum allowable charge’ plans.