Topcu 2019.

Study characteristics
Methods	Study design: split‐mouth RCT Conducted in: Turkey
Participants	Inclusion criteria: patients with bilateral, comparable impacted lower third molars with a symmetrical position and angulation Exclusion criteria: patients with a history of systemic diseases, alcoholism, drug abuse, and heavy smoking; patients with allergies to local anaesthetics, antibiotics, and anti‐inflammatories; and patients with acute infections at the time of surgery Age: mean 22.38 years Number randomised: 21 participants (42 sites) Number evaluated: 21
Interventions	Piezoelectric surgery versus conventional osteotomy Group 1 (n = 21): piezoelectric surgery (n = 21 impacted molars) Group 2 (n = 21): conventional osteotomy technique (n = 21 teeth) The second operation for the extraction of the contralateral impacted lower third molar was scheduled for 2 weeks after the first operation. All surgeries were conducted under local anaesthetic. All participants were instructed to take 500 mg of paracetamol 4 times a day postoperatively.
Outcomes	Neurosensory deficit and paraesthesia, pain (0‐to‐10 VAS), anxiety (State Trait Anxiety Inventory), operation time
Notes	2‐week interval between the 2 surgeries Paraesthesia was zero in both groups. 1 participant reported buzzing sound in the ear, which relieved at the follow‐up period.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: method of randomisation was not described. Recruitment details are not specified.
Allocation concealment (selection bias)	Unclear risk	Quote: "The osteotomy technique (piezoelectric surgery or conventional rotatory handpiece) was randomly allocated to be performed on the left or right side" Comment: it is unclear how or if the allocation was concealed
Blinding (performance bias and detection bias) patient	Unclear risk	Comment: it is not explicitly stated whether the participants were blinded or not
Blinding (performance bias and detection bias) assessor	Unclear risk	Comment: no mention of who carried out the postoperative measurements
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: no dropout
Selective reporting (reporting bias)	Low risk	Comment: all planned outcomes were reported
Other bias	Unclear risk	Quote: "The second operation for the extraction of the contralateral impacted lower third molar was scheduled 2 weeks after the first operation." Comment: a wash‐out period of 2 weeks may not be sufficient depending on healing from the first procedure