Gallo 2009.

Methods	Title: evaluation of 30% carbamide peroxide at‐home bleaching gels with and without potassium nitrate Trial design: double‐blinded, randomised controlled trial Location: not reported Language: English Number of centres: 1 Recruitment period: not reported Funding source: Dent Mat
Participants	Participants: adults Total number: 40 Inclusion criteria: shade darker than B65 no sensitive teeth not used a bleaching material in 5 years no restorations in their maxillary anterior teeth Exclusion criteria: unable to meet the time requirements reported cold‐sensitive teeth pregnant or nursing Number randomised: 40 Method of randomisation: not mentioned Method of allocation concealment: not mentioned Method of blinding: not reported Number evaluated: 40
Interventions	Total number of intervention groups: 2 30% carbamide peroxide with 5% potassium nitrate in tray 30% carbamide peroxide in tray Duration of treatment: 1 hour per day for 10 days
Outcomes	Change in tooth shade: Bioform Colour Ordered Shade Guide System: B85 darkest (1) to B59 lightest (24) Sensitivity of tooth: 0 to 10 scale (0: no pain, 10: severe) Gingival irritation: 0 normal, 1 mild, 2 moderate, 3 severe
Notes	Sample size calculation: not reported Adverse effects: sensitivity and gingiva irritation Health‐related quality of life: not reported Key conclusions of the study authors: "30% carbamide bleaching gels effectively whiten teeth without causing a significant increase in tooth sensitivity or changes in gingival condition. Potassium nitrate has little effect in sensitivity when treatment time is short" Correspondence required: no Contact: Dr John Gallo; jgallo@lsuhsc.edu
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "this double‐blinded, randomised clinical study evaluated the effectiveness..." However, method of randomisation not reported
Allocation concealment (selection bias)	Unclear risk	Not mentioned
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Quote: "Neither subjects nor evaluators knew which bleaching gel (treatment A….. was used.." However, method of blinding not reported
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Quote: "Neither subjects nor evaluators knew which bleaching gel (treatment A….. was used.." However, method of blinding not reported
Incomplete outcome data (attrition bias) All outcomes	Low risk	No mention of dropouts
Selective reporting (reporting bias)	Low risk	All outcomes described were reported. Conclusions are in accordance with the results
Other bias	Low risk	None