Papas 2009.

Methods	Title: placebo‐controlled clinical trial of use of 10% hydrogen peroxide whitening strips for medication‐induced xerostomia Trial design: randomised, double‐blinded, placebo‐controlled clinical trial Location: University School of Dental Medicine and New England Medical Center, USA Language: English Number of centres: 1 Recruitment period: not reported Funding source: supported, in part, by Procter & Gamble
Participants	Participants: mean age 50 years Total number: 42 Inclusion criteria: 4 or more anterior teeth xerogenic medication history and symptoms, subjects had to present with an unstimulated salivary flow ^ 0.2 ml/min Vita shade score of A2 or darker adults 18 and above Exclusion criteria: previous vital bleaching, apparent caries, periodontal disease chlorhexidine mouthwas used history of dentine hypersensitivity Number randomised: 42 Method of randomisation: not reported Method of allocation concealment: not reported Method of blinding: identical package and coded Number evaluated: 40 (1 withdrew and 1 did not report after 15 days)
Interventions	Total number of intervention groups: 2 Control: placebo Experimental: 10% hydrogen peroxide whitening strips Duration of treatment: 2 weeks
Outcomes	Tooth colour change Oral irritation and sensitivity b*: decreased b* indicates reduced yellowness; ΔL: increased ΔL is increased brightness
Notes	Sample size calculation: not reported Adverse effects: tooth sensitivity and gingival irritation Key conclusions of the study authors: "At day 8, the peroxide group experienced colour improvement relative to baseline and placebo. Mild and transient tooth sensitivity represented the most common adverse events. No subject discontinued treatment due to a product‐related adverse event" Contact: Athena S Papas, Tufts School of Dental Medicine, 1 Kneeland Street, Boston, MA 02111, USA; athena.papas@tufts.edu
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "A randomised double‐blinded placebo‐controlled clinical trial was conducted... eligible subjects were randomly assigned to .." However, the method of randomisation is not mentioned
Allocation concealment (selection bias)	Unclear risk	Not mentioned
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "Except for the presence or absence of peroxide, the test strips were identical in appearance. The test strips (peroxide or placebo) were dispensed in a small, white, cardboard box with instructions specifying twice daily strip application for 30 minutes before toothbrushing. To further ensure blinding, each box was labelled only with a unique subject identification number and necessary contact information"
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not reported
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "1 subject from placebo group voluntarily withdrew from the study.." Comment: 1 participant withdrew and 1 did not report after 15 days. Plausible effect size (difference in means) among missing outcomes not enough to have a clinically relevant impact on observed effect size
Selective reporting (reporting bias)	Low risk	All outcomes mentioned are reported adequately. Conclusions are in accordance with the results
Other bias	Low risk	None