Tam 2001.

Methods	Title: effect of potassium nitrate and fluoride on carbamide peroxide bleaching Trial design: split‐mouth, double‐blinded, randomised clinical trial Location: University of Toronto, Canada Language: English Number of centres: 1 Recruitment period: not reported Funding source: not reported
Participants	Participants: 20 to 53 years old with a mean age of 31 (10) years Total number: 42 Inclusion criteria: not reported Exclusion criteria: no previous history of desensitizing agents Number randomised: not reported Method of randomisation: not reported Method of allocation concealment: syringes were randomly numbered and selected for use Method of blinding: identical packs Number evaluated: 40
Interventions	Total number of intervention groups: 2 10% carbamide peroxide with 3% potassium nitrate and 0.11 fluoride ion wt/vol 10% carbamide peroxide Duration of treatment: 2 weeks
Outcomes	Tooth sensitivity Tooth whitening: patient‐reported improvement
Notes	Sample size calculation: not reported Adverse effects: sensitivity Key conclusions of the study authors: "A 10% carbamide peroxide bleaching gel containing potassium nitrate and fluoride produced less tooth sensitivity than did the control bleaching gel during a 2‐week at‐home bleaching treatment" Correspondence required: no Contact: Dr Laura Tam, laura.tam@utotonto.ca
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "double‐blinded randomised clinical trial." However, method of randomisation is not reported
Allocation concealment (selection bias)	Unclear risk	Quote: "syringes were randomly numbered and selected for use on either the left or right side of each patient's dental arch" Comment: we are not sure if the person allocating the participants and the person conducting the study are the same
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "formulations were manufactured specifically for this study (Ultradent) and were packaged identically for..."
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Quote: "double‐blinded randomised clinical trial." However, method of blinding is not reported
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Quote: "1 patient chose to discontinue treatment .... A total of 9 treatment days (out of a potential total of 294 treatment days) were missed by the patients, either because of general tooth sensitivity or for personal reasons" Comment: no clear mention of dropouts in the article
Selective reporting (reporting bias)	Low risk	All outcomes discussed have been reported adequately. Conclusions are in accordance with the results
Other bias	Low risk	None