Vogol 1992.

Study characteristics
Methods	Study design: parallel‐group randomized controlled trial Sample size: 36 Country: USA Setting: secondary care hospital Dates conducted: not reported Postoperative opioid used and delivery: not reported Pain score collection: patient self‐scoring Concurrent postoperative analgesics: none reported
Participants	Inclusion criteria Elective periodontal flap and osseous recontouring of at least 3 teeth Aged > 18 years old Co‐operative Good health Exclusion criteria Uncontrolled systemic disease Drug abuse Contraindication to NSAIDs Pregnancy and lactation Sedatives Antidepressants Analgesic use
Interventions	Group I‐pretreatment (19 participants): 600 mg ibuprofen 5‐10 mins before LA and placebo after suturing Group I‐post‐treatment (17 participants): placebo 5‐10 mins before LA and 600 mg ibuprofen after suturing
Outcomes	Postoperative pain (1‐4 ordinal scale every hour until 8 hours) Patient satisfaction (1‐5 scale at 8 hours) Time to analgesic request (hours) Adverse events (nonspecific during follow‐up)
Notes	Funding: not reported Declarations of interest: not reported Authors contacted: no Other: unable to include pain and patient satisfaction due to ordinal scales
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No mention. Quote: "Subjects were randomly distributed..."
Allocation concealment (selection bias)	Unclear risk	No mention. Quote: "Subjects were randomly distributed..."
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐dummy placebo used. Quote: "...600 mg ibuprofen immediately presurgically and placebo immediately after surgery"
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No mention
Incomplete outcome data (attrition bias) All outcomes	High risk	Seven participants excluded. Quote: "...7 were excluded from the efficacy analysis".
Selective reporting (reporting bias)	Unclear risk	No protocol
Other bias	Low risk	Similar baseline characteristics. Quote: "There were no statistically significant differences..."