Singh 2018.

Study characteristics
Methods	Study design: parallel arms Conducted in: India
Participants	Inclusion criteria: impacted mandibular third molar, patients between 18 and 40 years old, with recurrent pericoronitis, vital tooth with no periapical infection, vertical, mesio, or disto angular impaction Exclusion criteria: allergic to local anaesthesia, presence of infection and swelling, medically compromised patients, mobile teeth, and patients with horizontal impacted tooth Age: mean 24.9 +/‐ 3.933 years Number randomised: 30 Number evaluated: 30
Interventions	Coronectomy versus odontectomy Group 1 (n = 15): coronectomy Group 2 (n = 15): odontectomy All procedures performed under local anaesthetic. Postoperative antibiotics were given: ampicillin 250 mg, cloxacillin 250 mg, metronidazole 400 mg 3 times a day for 5 days, paracetamol 325 mg 3 times a day for 3 days
Outcomes	Pain (100‐millimetre VAS), swelling (facial measurements pre‐ and postoperation), nerve paraesthesia, trismus, postoperative infection, wound dehiscence, pocket depth, and root migration (by measuring fixed points on OPG radiographs)
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: the method of randomisation was not mentioned
Allocation concealment (selection bias)	Unclear risk	Comment: allocation concealment is not mentioned
Blinding (performance bias and detection bias) patient	Unclear risk	Comment: it is unclear whether participants knew which treatment they received
Blinding (performance bias and detection bias) assessor	Unclear risk	Comment: not described
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: no dropouts
Selective reporting (reporting bias)	Low risk	Comment: all planned outcomes were reported
Other bias	Unclear risk	It is unclear why 1 participant had cone beam tomography and the other participants did not, in this "randomised prospective study".