Tedesco 1992.

Methods	Trial design: parallel (2 arms) Location: Oral Health Enhancement Clinic, Greater Buffalo metropolitan area, New York, USA Number of centres: 1 Study Duration: recruitment and follow‐up dates not reported. Participants followed‐up at 9 months
Participants	Participants: individuals between the ages of 21 and 65 were recruited from the Greater Buffalo metropolitan area Inclusion criteria: participants were required to have mild to moderate gingivitis, defined as at least 55% of oral sites with gingival bleeding on probing (scores of 2 or 3 on the Löe and Silness gingival index (Löe 1963; Silness 1964)) and to have at least at least 10 teeth per dental arch Exclusion criteria: all prospective participants were required to have a screening visit prior to acceptance into the study and were disqualified if they had any area with periodontal attachment loss greater than 1.5 mm, radiographic evidence of bone loss greater than 25% (anterior/posterior bitewing radiographs or periapical radiographs), or previous periodontal therapy. Study participants were required to be in good health (no diabetes or heart disease), not pregnant, and not taking medications, including antibiotics, for any chronic diseases Age at baseline (mean years): intervention group: 32.9; control group: 31.3 Gender: intervention group: female 56 (51%), male 55 (49%); control group: female 24 (43%), male 32 (57%) Number randomised: 167 (intervention group: 111; control group: 56) Number evaluated: 91 (intervention group: 62; control group: 29)
Interventions	Participants visited the clinic 7 times over a 14‐month period. Visits 1 and 2 provided baseline measures, and visits 2 through 5 were intervention (experimental) or control visits. Visits 6 and 7 were 3‐month and 9‐month follow‐up visits, respectively Intervention: at visit 2, study participants received traditional oral hygiene instruction in the same manner as control group participants. The same standardized delivery and management of the visit were employed. Before the second prophylaxis was performed, however, study participants were shown a phase contrast slide of their own subgingival flora on a video monitor. A videotape record was made simultaneously. During video monitor viewing, the hygienist described and labelled the patient's oral pathogens and explained their association to the development of periodontal disease. The patient was encouraged to ask questions and offer his or her reactions to the video monitor display. The patient received a complete prophylaxis and then a new slide was made, viewed on the video monitor and recorded on videotape to show the subject the relative absence of bacteria. The hygienist emphasized that this was the picture of a healthy mouth. Emphasis was placed on how the patient can control the health of his/her mouth and always "possess" this picture of wellness. Visits 3, 4, and 5, following 1 month after each other, repeated the intervention, with the subject watching the videotape from the previous visit and viewing a fresh slide on the video monitor made at the visit in progress. During these visits emphasis was placed on the patient's accomplishments; i.e. performance accomplishments. The patient's and hygienist's conversations and descriptions of the video monitor display were linked to the plaque index and gingival index scores, problem areas, etc., detected clinically by the hygienist. At visits 6 (3‐months post‐intervention) and 7 (9‐months post‐intervention) assessments were taken as follow‐up procedures, and a final prophylaxis was performed before terminating study participation Control: at visit 2 control group participants received traditional oral hygiene instruction that included brushing and flossing techniques from a hygienist. Study participants were also given feedback on their entry state of oral hygiene, with problem areas for improvement emphasized. The hygienist also explained the range and meaning of plaque index and gingival index scores. Control group participants were encouraged to present problems and ask questions. Before dismissal, a complete oral prophylaxis was performed. Psychological and social assessment instruments were also administered during these visits. At visits, 3, 4, and 5 patients were given feedback on how clean their teeth and gingival surfaces were, and what areas needed most improvement, and assessments (clinical, psychological, and social) were taken. At visits 6 and 7 follow‐up assessments were taken and a final prophylaxis was performed Prophylaxis provided: prophylaxis provided to both groups Member of dental team delivering intervention: hygienist Frequency of intervention: intervention group: 7 visits with 4 visits of OHA; control group: 7 visits with 4 visits of OHA Intensity of intervention (length of time): intervention group: not reported; control group: not reported Setting: not reported Disease level: mild to moderate gingivitis
Outcomes	Self‐efficacy assessed via Oral Health Behaviour Expectation Scale Theory of reasoned action variables assessed via Theory of Reasoned Action Oral Health Scale Self‐reported brushing and flossing behaviours Plaque accumulation (Löe and Silness plaque index, Löe 1963) Gingival inflammation (Löe and Silness gingival index, Silness 1964) Brushing and flossing skill observation
Notes	Funding: "The study was supported by NIH‐NIDR grant DE‐07335" Sample size calculation: not reported Adverse effects: not reported Declarations/conflicts of interest: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "Subjects were randomly assigned to experimental or control groups" Comment: insufficient information on the method of random sequence generation
Allocation concealment (selection bias)	Unclear risk	Not mentioned Comment: insufficient information on allocation concealment
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Quote: "All procedures were trained to a written script and intervention protocol. In addition to periodic recalibration exercises, the hygienist was periodically monitored for appropriate intervention delivery, communication, and patient feedback" Comment: patient and personnel would have been aware of allocation. Blinding of participants was not possible; it is unclear the influence this would have on the risk of bias for this domain
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Quote: "1 hygienist completed all the plaque and gingival assessments following the screening. She received calibration training prior to her work on this project. All procedures were trained to a written script and intervention protocol. In addition to periodic recalibration exercises, the hygienist was periodically monitored for appropriate intervention delivery, communication, and patient feedback" Comment: it is possible that there was only 1 hygienist involved who provided intervention and outcome assessment. No response from contact author regarding further information. Unclear if outcome would have been influenced
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "At the last intervention visit (Visit 5), 18.6% of the sample did not return. This dropout rate increased to 28.7% and 45.5% by Visit 6, (3‐month follow‐up), and Visit 7 (9‐month follow‐up), respectively. Dropout rates were similar for both experimental and control groups; by the end of the study, 52% of the control group and 56% of the experimental group remained. Dropouts at Visits 6 and 7 were disproportionally represented in the lower income and education groups (less than high school education and income under $20,000). In addition, there was a difference for race, with proportionally more non‐Caucasian minorities leaving the study by Visits 6 and 7 than Caucasian subjects (who outnumbered minority groups 4:1 at the beginning of the study). When compared with participants, dropouts at Visits 6 and 7 had higher plaque and gingival index scores at Visits 5 and 6. The same pattern emerged for per cent "0" gingival index scores; that is, dropouts had a lower percentage of non‐bleeding sites (poorer oral health status) when compared with all study participants"
Selective reporting (reporting bias)	Low risk	All outcomes in methods section were reported
Other bias	Low risk	Quote: "Prospective subjects were offered 3 free cleanings and free oral health education for their participation in 7 visits at the Oral Health Enhancement Clinic" Comment: unlikely to influence outcome