The effectiveness of interventions in reducing pain related to orthodontic separation: a systematic review and meta-analysis

Background Pain is an unpleasant experience and annoying sensation. To control this pain during orthodontic separation, different pharmacological and non-pharmacological methods have been used.Objective This systematic review and meta-analysis aimed to critically assess the evidence of the effectiveness of pharmacological and non-pharmacological methods in reducing pain induced by orthodontic separation.Search strategy An electronic search was conducted using the following databases: PubMed (R) (Medline), Scopus (R), EMBASE (R), Web of ScienceTM, Google ScholarTM, ProQuest, and Cochrane Central Register of controlled trials (CENTRAL) searching for the studies published between January 2012 and April 2023.Selection criteria Only randomized controlled trials (RCTs) were included, each experimental group included patients who received elastomeric separators and one kind of pharmacological or non-pharmacological interventions for pain reduction during the separation stage.Data collection and analysis Cochrane's risk of bias tool (RoB2 tool) was applied. The Grading of Recommendations Assessment, Development, and Evaluation [GRADE] approach was used to evaluate the strength of the evidence.Results Thirty-one studies (RCTs) were included in this systematic review. Nineteen of them were appropriate for quantitative synthesis and used VAS for pain assessment. Meta-analysis showed that low-level laser therapy (LLLT) was an effective approach for pain relief after separators placement with standard mean difference of 13.79 mm (95% confidence interval (CI): -15.64, -11.94) at 6 h and 23.34 mm at 24 h (95% CI: -25.91, -20.77). LLLT was also effective when applied in split-mouth and the standard mean difference was 8.9 mm at 6 h (95% CI: -12.86, -3.33) and 17.15 mm at 24 h (95% CI: -30.12, -4.17). Ibuprofen had a pain control effect at 6 h and at 24 h compared with the placebo group. The standard mean difference was 14.37 mm (95% CI: -20.54, -8.19) and 20.46 mm (95% CI: -27.79, -13.13), respectively. There was no difference in pain control between ibuprofen and acetaminophen. Naproxen had lower visual analog scale scores in pain perception at 6 h and the standard mean difference was 7.03 mm (95% CI: -12.67, -1.40).Conclusions The application of LLLT decreased the pain induced by the separation during the first day of teeth separation; the pain reduction showed an increase from 6 h to the end of the 24 h. However, the evidence is weak to moderate. The analgesics reduced the pain compared to placebo; this pain reduction had shown an increase from 6 h to the end of the 24 h. The strength of the evidence is moderate. Naproxen gel effectively reduced the pain compared to placebo; the evidence in this regard is moderate. Naproxen gel effectively reduced the pain compared to placebo, but it was less effective than the oral intake of non-steroidal anti-inflammatory drugs. However, the evidence in this regard is moderate.Registration This systematic review was registered with PROSPERO (CRD42022335553) during the first stages of its conduction.