Your insurance policy is an agreement between yourself and your insurance company. There is usually a lifetime maximum per person. How you decide to finance your orthodontic treatment is your decision and does not affect how your insurance company will reimburse you. Most insurance companies will only reimburse you for services rendered as they occur. In orthodontics this means up to one third of the total cost when treatment starts and each following month an equal portion of the remainder for the estimated duration of treatment until the maximum has been reached.