2. Unuseable published data related to swelling at 7 days.

Studies	Comparison	Subgroup	Reasons
Şimşek Kaya 2019	Flap design	Modified triangular flap vs envelope	Presented as % of change from baseline. Data could not be used. Authors were contacted to obtain raw data but no reply received.
Mobilio 2017	Flap design	Envelope flap vs triangular flap	To assess swelling, the average percentage value was obtained from 5 distances (in mm) through 6 facial points (angle of the mandible to tragus, to eye outer canthus, to labial commissure, to nasal border, and to soft pogonion).
Arakji 2016	Bone removal techniques	Conventional techniques vs piezoelectric surgery	Swelling data were presented by taking the mean of the distance of more than 1 measurement, and the raw data were not provided.
Basheer 2017	Bone removal techniques	Piezoelectric vs rotary osteotomy technique	Mean of different measurements
Bhati 2017	Bone removal techniques	Piezoelectric vs rotary osteotomy technique	Mean of multiple measurements
Mantovani 2014	Bone removal techniques	Piezoelectric surgery vs conventional	Overall swelling or oedema (E) was calculated and expressed as E = [Σdi2/4]0.5, where Σdi is the sum of the 4 facial reference measurements (G‐T, G‐C, G‐S, G‐P).
Mistry 2016	Bone removal techniques	Piezoelectric vs rotary osteotomy technique	Distance between extraoral and intraoral reference points was measured with divider to assess the swelling.
Piersanti 2014	Bone removal techniques	Conventional techniques vs piezoelectric surgery	Swelling data were presented by taking the mean of the distance of more than 1 measurement, and the raw data were not provided.
Acar 2017	Suturing techniques	Horizontal mattress suturing vs simple interrupted suturing	Postoperative swelling was evaluated by measuring the changes of the 5 distances on the face of the participants preoperatively and postoperatively.
Gogulanathan 2015	Suturing techniques	Fibrin sealant vs conventional suturing	Swelling raw data were not provided.
Kumar 2016	Surgical drain	Tube drain vs none	Means of horizontal and vertical measurements
Pachipulusu 2018	Primary vs secondary wound closure	Primary vs secondary closure of the surgical wound	Swelling data presented as a percentage of the differences between pre‐op and post‐op measurements.
Kumar 2015	Wound closure with autologous platelet concentrates	PRF vs none	Swelling data were presented as a percentage of the differences between pre‐ and postoperative measurement.
Uyanik 2015	Wound closure with autologous platelet concentrates	PRF or a combination of PRF and piezoelectric surgery vs conventional rotatory osteotomy	Swelling data presented as a percentage of the differences between pre‐op and post‐op measurements.
Dutta 2016	Wound closure with autologous platelet concentrates	PRF vs none vs PRF+ hydroxyapatite	Mean of 3 measurements
Kapse 2019	Wound closure with autologous platelet concentrates	PRF vs none	Swelling data presented as a percentage of the differences between pre‐op and post‐op measurements.

PRF: platelet rich fibrin; vs: versus.