Münster Halvari 2012.

Methods	Trial design: parallel (2 arms) Location: Colosseum Dental Clinic in Sandvika, Norway Number of centres: 1 Duration: recruitment and follow‐up dates not reported. Participants followed‐up at 5.5 months
Participants	Participants: 158 adults Inclusion criteria: adult participants that showed up at the clinic, understood Norwegian, and gave informed consent Exclusion criteria: periodontal pockets ≥ 4.0 mm, as measured by a pocket probe, and/or serious bone loss visualized by digital X rays during the dental examination; significant additional oral or other diseases; pregnant women Age at baseline (years): range 18 to 32, mean age 23.31 years, SD =3.5 Gender: total: 112 (71%) female and 46 (29%) male Number randomised: 158 (intervention group: 79; control group: 79) Number evaluated: 141 (intervention group: 70; control group: 71)
Interventions	Quotes: "When participants first arrived at Time 1a (T1a; ........), they completed a survey assessing autonomy orientation, autonomous motivation for dental home care, perceived dental competence, dental behaviours, and demographics. The standard oral examination. The exam lasted about 45 minutes for all participants, during which time T1a oral health variables were assessed. The DH was autonomy supportive when giving the information about the examination. The DH addressed an introduction to the exam (5 minutes); measures of dental plaque and gingivitis on all teeth surfaces (112 for patients with all teeth intact; 20 minutes); clinical and X‐ray exam for caries (5 minutes); and pocket exam (5 minutes). The final dialogue lasted about 10 minutes and included information on how caries looks and how to detect it on patients' own X rays, and the importance of choice and self‐initiation regarding treatment options in order to promote an informed basis for patient choice and decision making (Beauchamp & Childress 2001)" and "Immediately thereafter, a 45‐minute intervention took place for the experimental group, whereas control group participants went directly to a 45‐minute standard teeth cleaning. The experimental group received the cleaning after the intervention. The cleaning in both groups was done in an autonomy‐supportive way" Intervention: "The DH started the intervention by asking participants about their perceived oral health and problems, and listening to and acknowledging their feelings and perspectives, before giving competence‐related information about their perceived oral health and problems. Based on this conversation, the contents of the intervention were (a) education in plaque‐related diseases such as gingivitis, periodontitis, and caries; (b) demonstrating effective brushing and flossing, with participants practicing these tasks and receiving positive feedback and corrections; (c) giving health promotion and disease preventive information, and offering rationales for the dental behaviours by explaining the relations of behaviours to disease prevention and health; (d) giving information about the value of fluorides and regular meals; and (e) offering choice and options concerning their dental home care" Control: "This 45‐minute cleaning was given to the control group after the exam and to the experimental group after the intervention. The DH focused on the importance of removing calculus in order to make participants' dental home care easier to perform. The cleaning made the baseline the same for both groups." "The control group was viewed as having received usual care; however, because of ethical considerations, the emphasis on patient autonomy support in this clinic likely made this usual‐care condition more autonomy supportive than would have been the case in other clinics. If that were so, it would make the test of the intervention more stringent than if usual care had been provided without the autonomy support, as the primary difference between the 2 groups would likely have been just the competence enhancing intervention itself and/or any possible interaction between the intervention and the autonomy support" Prophylaxis provided: scaling at baseline Member of dental team delivering intervention: hygienist Frequency of intervention: intervention group: 1 visit with OHA; control group: 1 visit with OHA Intensity of intervention (length of time): intervention group: 90 minutes; control group: 45 minutes Setting: primary care Disease level: routinely attending adults with no signs of periodontal disease
Outcomes	Clinical outcomes: dental plaque (dental plaque index (Löe 1967)), gingivitis (dental gingival index (Löe 1967)). Both plaque and gingivitis were assessed on distal, buccal, mesial, and lingual tooth surfaces on all teeth except third molars. A participant's scores were the sums for plaque and gingivitis, respectively, divided by the total number of surfaces measured. For the purpose of reliability estimation for plaque and gingivitis, the average scores of each of the 4 teeth quadrants as indicators, and used observations of plaque in the 4 teeth quadrants in modelling of latent indicators for plaque in Structural Equation Modeling (SEM) Psychological outcomes (questionnaires): autonomy orientation (Dental Care Autonomy Orientation Scale), perceived autonomy support (6‐item version of the Health Care Climate Questionnaire (Williams 1996)), autonomous motivation for the dental project (Evaluation of Dental Project Scale (Halvari 2006)), autonomous motivation for dental home care (a 3‐item identified subscale of the Self‐Regulation for Dental Home Care Questionnaire (Halvari 2012)); perceived dental competence (Dental Coping Beliefs Scale (Wolfe 1996) using the 5 items with the best factor loadings (Halvari 2006) and 2 added items from a previous study (Halvari 2010)); dental health behaviours (dental health behaviour was assessed by a 4‐item formative composite scale (Halvari 2010))
Notes	Funding: "The Faculty of Odontology, University of Oslo, for funding the 4‐year PhD period; the Norwegian Ministry of Health, who funded the study" Sample size calculation: "A power analysis using data from a previous study (Halvari 2006) indicated that the necessary number of participants in each group should be 14 for dental plaque, 18 for gingivitis, and 56 for perceived competence to detect significant differences (using t tests) between averages for the experimental and control groups with a power of .90 (α = .05). Based on the power estimates and an unknown participant dropout from Time 1 to Time 2, 79 participants were randomly assigned to each condition and were considered to be sufficient" 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: "After the exam, 79 participants were randomly assigned to each condition" Comment: insufficient information on the method of random sequence generation
Allocation concealment (selection bias)	Unclear risk	Quote: "Immediately thereafter, a 45‐minute intervention took place for the experimental group, whereas control group participants went directly to a 45‐minute standard teeth cleaning. The experimental group received the cleaning after the intervention. The cleaning in both groups was done in an autonomy‐supportive way" Comment: insufficient information on allocation concealment
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Quote: "This 45‐minute cleaning was given to the control group after the exam and to the experimental group after the intervention" Comment: the dental hygienist providing the intervention also provided the baseline 'cleaning' and would therefore be aware of the 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: "At T2 (after 5.5 months), participants responded to all the same questionnaires completed before the teeth exam at T1a, except autonomy orientation and demographics, which were not included at T2. Then, the second teeth examinations were conducted by a different DH than the one for T1a. The second DH was blind to experimental conditions" Comment: the examiner did not know which group the participants they were assessing had been assigned to
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: all participants accounted for, explanation of dropouts provided
Selective reporting (reporting bias)	Low risk	All outcomes in methods section were reported
Other bias	Low risk	Quote: "207 potential participants from the University of Oslo indicated interest in the study on motivation and dental behaviour after seeing a poster or being approached by the researcher... They were informed that they would get a free dental examination, a free dental cleaning, and a chance to win travel worth NOK 10000 (about USD 1700)" Comment: unlikely to influence outcome