OBJECTIVE: To evaluate the impairment of orthodontic tooth movement caused by nonsteroidal antiinflammatory drugs (NSAIDs). DATA SOURCES: Biomedical literature accessed through MEDLINE (1966–January 2000), EMBASE (1980–January 2000), and International Pharmaceutical Abstracts(1970–January 2000). Key search terms included NSAIDs, orthodontics, and tooth movement. DATA SYNTHESIS: Orthodontic dentistry applies mechanical force to generate tooth movement. Since prostaglandins are mediators of tooth movement, it is reasonable to expect that prostaglandin inhibitors, such as NSAIDs, inhibit or delay tooth movement. An evaluation of studies measuring the extent of NSAID impairment on tooth movement was undertaken. CONCLUSIONS: Results from animal studies have shown that NSAIDs can impair the tooth movement process. Until long-term human data are obtained, acetaminophen remains an appropriate alternative to NSAIDs for treating orthodontic-associated pain.