Rullo 2013.

Study characteristics
Methods	Study design: RCT (split‐mouth), procedures 30 days apart Conducted in: Naples, Italy Number of centres: 1 Recruitment period: not stated
Participants	Inclusion criteria: (a) the presence in each person of bilateral and symmetrically oriented impacted lower third molars to be extracted for prophylactic reasons; (b) forceps extractions not requiring osteotomy were excluded; (c) no systemic diseases; (d) age > 18 years; (e) non‐smoker; (f) not pregnant; and (g) no allergy to penicillin or other drugs used in the standardised postoperative therapy Exclusion criteria: patients who were taking antibiotics for current infection or who had acute pericoronitis or severe periodontal disease at the time of operation Mean age: 26.2 years, range 18 to 54 years. Male 20, female 32 Number randomised: 52 Number evaluated: 52
Interventions	Piezoelectric bone removal versus bur Group A (n = 52): piezoelectric hand‐piece operating with modulated ultrasound with a functional frequency of 25e29 kHz and a digital modulation of 30 kHz. The inserts moved with a linear vibration of between 60 and 210 mm. Group B (n = 52): osteotomies using a conventional rotating drill were carried out with a Stryker tungsten carbide bur mounted on a surgical high‐speed hand‐piece Procedures subgrouped into "simple extractions" and complex extractions. All procedures performed under local anaesthetic, and drain inserted. All participants received amoxicillin (500 mg 3 times daily for 7 days starting day before surgery), ibuprofen 600 mg 3 times daily for 4 days, and CHX mouthwash. Follow‐up: VAS (0 to 10) for pain completed daily for 6 days
Outcomes	Duration of procedure, pain (100‐point VAS), surgical difficulty (Parant scale), histological analysis of bone biopsy samples
Notes	Sample size calculation: not reported All procedures performed by the same surgeon. E‐mail sent to authors requesting additional information.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quotes: "...the instruments were randomly selected using a coin toss", "instrument sequence was random"
Allocation concealment (selection bias)	Unclear risk	Unclear who performed the coin toss and exactly how the first extraction side was chosen
Blinding (performance bias and detection bias) patient	Unclear risk	Participants and clinicians could not be blinded to allocated treatments.
Blinding (performance bias and detection bias) assessor	High risk	No blinding of outcome assessment undertaken.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Unclear how many procedures were included in the simple and complex subgroups, for each procedure
Selective reporting (reporting bias)	High risk	Pain measured and reported. It seems likely that attempts were made to measure swelling and trismus, but these outcomes were not reported because the measures were "not reproducible".
Other bias	High risk	The outcomes in the graphs and in the tables are contradictory.