Table 1 Inclusion and exclusion criteria

Inclusion Criteria

 1. The study was a randomized controlled trial (RCT);

 2. studies compared NSAIDS with placebo for orthodontic pain using quantitative outcome data;

 3. As for the experiment intervention, Participators were not allowed to be currently taking any antibiotics or analgesics, with no teeth extractions at least two weeks before the appointment and on contraindications or adverse reactions to NSAIDS;

 4. The outcomes of pain perception were measured by either visual analog scale (VAS) or a questionnaire for pain perception;

 5. Duration of follow-up was assessed and defined as short term (eg: 2 h, 6 h, 24 h,7 days).

Exclusion Criteria

 1. Studies were cohort studies, review articles, case reports, descriptive studies, opinion articles, and abstracts;

 2. The subjects had systemic disease or chronic pain or histories of neurologic and psychiatric disorders;

 3. Patients had any acute or chronic dental, periodontal or gingival problems which could cause pain.