Felo 1997

Methods	Randomised, parallel group study. Patients cannot be blind, outcome assessor blind. No withdrawals.
Participants	Adults. Age 35 to 75. 24 enrolled and results given for 24.
Interventions	2 groups. Antiseptic subgingival irrigation (100 ml chlorhexidine 0.06%) once per day versus rinsing (20 ml chlorhexidine 0.12) once daily. Study duration: 3 months.
Outcomes	Turesky modification of Quigley‐Hein plaque index, a modification of the Ainamo and Bay bleeding index, Lobene Stain Index (no SD were given so it could not be used) at 3 months.
Notes	The article reported that 2 ml of chlorhexidine (0.12%) was used. The authors replied that it was a print mistake and that a quantity of 20 ml was used. The Ainamo and Bay bleeding index was recorded using a "sweeping motion" and not with a "gentle probing". Trial described as double‐blind, but two different procedures were used. The author replied that the patients did not know if they got a placebo mouthrinse or chlorhexidine.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Subjects were randomly assigned by a computer‐generated random code to one of two groups".
Allocation concealment (selection bias)	Low risk	"Subjects were randomly assigned by a computer‐generated random code to one of two groups".
Blinding (performance bias and detection bias) All outcomes	Low risk	"One trained examiner blinded to the subjects' assignment of mouthrinse or irrigation performed all the measurements".
Incomplete outcome data (attrition bias) All outcomes	Low risk	All data reported. No loss to follow‐up.
Selective reporting (reporting bias)	Low risk	All data reported.
Other bias	Unclear risk	The study was partly supported by grants from Colgate Oral Pharmaceuticals and Teledyn Water Pik.
Blinding of the patient?	Low risk	Written to the authors. Replied that the patients do not know if they got a placebo mouthrinse or chlorhexidine.