Cronin 1997.

Methods	Trial design: parallel group, 2 arms Location: not reported Number of centres: not reported Recruitment period: not reported
Participants	Inclusion criteria: healthy dentate adults with sufficient levels of plaque and gingivitis, more than 20 natural teeth, brushing teeth at least twice daily, flossing no more than once a week Exclusion criteria: gross carious lesions, fully crowned or restored teeth, orthodontically banded teeth, abutment teeth and third molars, major hard or soft tissue lesions, taking medication affecting gingival health (hormones, antisialologues, steroids), antibiotics intake within 30 days of enrolment, a history of rheumatic heart disease, diabetes mellitus or hepatitis. Females who were pregnant, lactating or planning a pregnancy. A physical condition limiting manual dexterity, dental prophylaxis within 30 days of enrolment, grossly neglected oral hygiene, advanced periodontitis, calculus sufficient to interfere with scoring plaque, inflammation, wide embrasure areas or advanced gingival recession. Baseline plaque status: supragingival plaque score (Turesky modification of Quigley & Hein Plaque Index) score > 2.0 Baseline periodontal status: Löe & Silness Gingival Index score within the range 1.0 to 1.6 Age at baseline: Gp A: 20 to 59 years, mean age 35.7 (10.9); Gp B, range 22 to 65 years, mean age 36.6 (10.4) Sex: 16 males/43 females (Gp A 8/22), (Gp B 8/21) data presented only for evaluated participants Number randomised: 60 (Gp A 30, Gp B 30) Number evaluated: 59 (Gp A 30, Gp B 29) Attrition: 1 participant in Gp B (floss) failed to attend for the final examination Smoking status: not reported
Interventions	Comparison: manual toothbrushing plus rubber/elastomeric tooth cleaning stick (electric interdental cleaning device, ID2) versus manual toothbrushing and floss Gp A (n = 30 evaluated) Braun Oral‐B interclean with Flexi‐Tip attachment (ID2 ‐ electric interdental cleaning device) Toothbrush twice a day and interdental device (ID2 with Flexi‐tip attachment) once a day Gp B (n = 29 evaluated) manual waxed floss (Johnson & Johnson) All participants used manual toothbrushes twice daily and Colgate Regular toothpaste Toothbrush twice a day and floss once a day Duration of intervention: 4 weeks Baseline cleaning: at day 1, all participants received supragingival scaling and a prophylaxis Training: written and verbal instructions given to each participant, told not to use any additional mechanical or chemical plaque removing agents during the study Compliance assessment: not reported
Outcomes	Measurements: at day 1 and week 4 Dental plaque: plaque index, Turesky modification of Quigley & Hein Plaque Index Periodontal disease ‐ gingivitis: Löe & Silness Gingival Index (GI) (bleeding index scores derived from the gingival index data) Adverse effects: at each study visit, safety was assessed by examinations of intra‐ and extra‐oral tissues; safety analyses revealed no evidence of irritation or gingival abrasion in either group, no adverse events were observed or reported Attrition: 1 participant in the floss group did not attend the week 4 assessment.
Funding	Not reported. One author Braun employee
Notes	At baseline, the floss group had statistically significant higher gingival and bleeding indices compared to the ID2 group. All clinical examinations were performed by the same (blinded) examiner.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "eligible subjects were randomized to receive either dental floss or the ID2 with Flexi‐Tip attachment" Comment: participants were randomised to groups, but the paper did not indicate the means of randomisation
Allocation concealment (selection bias)	Unclear risk	No description of how the allocation sequence was concealed. Allocation concealment not mentioned
Blinding of participants and personnel (performance bias) All outcomes	High risk	Blinding of participants not possible
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "all clinical examinations were performed by the same (blinded) investigator"; "to ensure that the study investigator remained blinded, instructions for the use of the respective devices were given independently by a licensed, registered dental hygienist" Comment: the examiner did not know which groups the participants had been allocated to
Incomplete outcome data (attrition bias) All outcomes	Low risk	All data reported, including 1 participant in the control group who did not return for the week 4 measurements
Selective reporting (reporting bias)	Low risk	No protocol available. All outcomes stated in the Methods section were addressed in the Results.
Other bias	Unclear risk	Compliance not assessed Baseline difference noted by trial authors