Opiate Replacement Therapy (ORT) is the medical procedure of replacing an addictive full agonist opiate such as heroin with a longer acting but less euphoric full agonist opiate such as methadone.
Some argue buprenorphione treatment is not replacement therapy, because "replacement therapy" implies an equality to street drugs like heroin and treatment medications like buprenorphine.
The term suggests a lateral move from illegal addiction to legal addiction and this does not accurately characterize the true nature of the treatment. The essence of addiction is uncontrollable compulsive behavior.
The first goal of addiction treatment is to stop this dangerous addictive behavior. With successful buprenorphine therapy, as part of a comprehensive treatment plan, the dangerous addictive behavior is stopped not replaced.