Baab 1986.

Methods	Trial design: parallel (2 arms) Location: University of Washington's Graduate Periodontics Clinic, USA Number of centres: 1 Study Duration: February, March and April, 1982. Participants followed‐up at 6 months
Participants	Participants: the subjects had completed active periodontal treatment, including surgery, at least 1 year previously at the University of Washington's Graduate Periodontics Clinic, and were being seen by dental hygienists every 3 months for oral hygiene instruction, scaling and root planing Inclusion criteria: those selected had at least 20 teeth present, including 2 contralateral molars Exclusion criteria: no physical handicaps affecting vision or manual dexterity Age at baseline (years): range 30 to 76 Gender: 18 (55%) women and 15 (45%) men Number randomised: 33 (no group breakdown) Number evaluated: 31 (intervention group 15; control group 16)
Interventions	Intervention: OH instruction using a self‐inspection plaque index. Basic treatment including: ‐ baseline questionnaire, plaque and bleeding indices, OH skill assessment, plaque index (after OH), OH instruction and scaling; ‐ OH instruction at 2 weeks; ‐ plaque and bleeding indices, OH skill assessment, plaque index (after OH) and OH instruction at 1.5 months; ‐ plaque and bleeding indices, OH skill assessment, plaque index (after OH), OH instruction and scaling at 3 months; ‐ plaque and bleeding indices, OH skill assessment and plaque index (after OH) at 6 months. Oral hygiene instruction for the 15 patients in the self‐inspection group consisted of the following steps. First, the "Oral self‐inspection manual" (Baab 1983) was used to guide the patients to score the presence or absence of disclosed plaque on 6 index teeth. Teeth 11, 26, and 36 were to be assessed from the lingual, using a lighted dental mirror (Mirolite #711®), and 16, 41, and 46 were to be scored from the facial. If an index tooth was missing, the next tooth distally was used. A line drawing of each index tooth indicated 2 interdental areas and 1 radicular area, near the gingiva, to be scored. The self‐inspection plaque index (SIPI) consisted of the total surfaces out of 18 (3 surfaces per tooth) with disclosed plaque. Patients were guided by the manual to interpret their scores and to correct deficiencies in plaque removal. No particular brushing stroke was advocated because evidence is lacking that any one technique is superior to another (Rugg‐Gunn 1979). After the instructional session, the patients were given 24 erythrosin disclosing wafers (Xpose"*), the lighted dental mirror, the manual and the oral hygiene tools they had selected. Patients were asked to examine the 6 teeth for disclosed plaque once each week following personal oral hygiene. During follow‐ up visits at 2 weeks, 1.5 months and 3 months, the hygienist provided immediate feedback on the patients' SIPI accuracy, and reviewed the patients accuracy and reviewed the patients' self‐scoring charts Control: traditional instruction using professional monitoring of disclosed plaque. Basic treatment including: ‐ baseline questionnaire, plaque and bleeding indices, OH skill assessment, plaque index (after OH), OH instruction and scaling; ‐ OH instruction at 2 weeks; ‐ plaque and bleeding indices, OH skill assessment, plaque index (after OH) and OH instruction at 1.5 months; ‐ plaque and bleeding indices, OH skill assessment, plaque index (after OH), OH instruction and scaling at 3 months; ‐ plaque and bleeding indices, OH skill assessment and plaque index (after OH) at 6 months. The 16 patients in the traditional group were shown where disclosed plaque remained after the oral hygiene skills assessment. The hygienist observed the patients' cleaning and afterward gave feedback regarding how long they spent brushing the facial and lingual surfaces and how effectively they used oral hygiene aids. The dental hygienist was given a relatively free hand regarding the instructional methods; emphasis was placed on plaque removal skills using the various oral hygiene aids, rather than on self‐assessment of disclosed plaque. Information concerning the SIPI was not provided, and disclosing wafers and lighted dental mirrors were not dispensed 30 minutes were spent on oral hygiene instructions at follow‐up visits for both groups Prophylaxis provided: scaling at baseline and 3 months Member of dental team delivering intervention: hygienist Frequency of intervention: intervention: 5 visits with repeated OH instruction; control: 5 visits with repeated OH instruction Intensity of intervention (length of time): intervention: 30 minutes; control: 30 minutes Setting: secondary care Disease level: high caries rate
Outcomes	Oral hygiene and gingival health were assessed by recording the presence or absence of disclosed plaque at the gingival margin (O'Leary 1972) and bleeding upon measurement probing (Van der Velden 1979). Mean observed time (seconds) spent brushing the facial and lingual surfaces during the oral hygiene skill assessment. Total time (minutes) spent by patients in oral hygiene procedures during the oral hygiene skill assessment at the initial and subsequent examinations (mean + standard deviation). Mean number of oral hygiene aids selected by subjects for the oral hygiene skill assessment at the initial and subsequent examinations
Notes	Funding: this study was supported by a Biomedical Research Support Grant #RR‐ 05346 from the National Institutes of Health 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)	Low risk	Quote: "Subjects were randomly assigned by rolling of dice to 2 groups, self‐inspection and traditional, before the initial examination"
Allocation concealment (selection bias)	Unclear risk	Not reported Comment: insufficient information on allocation concealment
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Quote: "The dental hygienist was given a relatively free hand regarding the instructional methods" Comments: personnel were aware of intervention 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	Low risk	Quote: "2 raters, who were unaware of the group assignments, examined the patients initially, and at 1.5, 3 and 6 months"
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Comment: 2 dropped out, unsure of allocation
Selective reporting (reporting bias)	Low risk	All outcomes in methods section were reported
Other bias	Unclear risk	Comment: SIPI group and traditional group were significantly different at baseline regarding plaque scores and time spent brushing facial aspects of teeth