Summary of findings 9. CP gel in tray versus CP gel in tray for whitening teeth.
| Carbamide peroxide (CP) gel in tray compared to CP gel in tray for whitening teeth | ||||||
| Patient or population: adults undergoing bleaching Setting: home‐based Intervention: CP gel in tray Comparison: CP gel in tray | ||||||
| Tooth whitening ‐ assessed by the dentist | ||||||
| Comparisons | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | Number of participants (studies) | Certainty of the evidence (GRADE) | Comments | |
| Risk with CP gel in tray | Risk with CP gel in tray | |||||
| 10% CP versus 10% CP ‐ 2 weeks (higher RR indicates whiter) | Study population | RR 1.03 (0.90 to 1.18) | 66 (1 RCT) | ⊕⊝⊝⊝ VERY LOW1, 2 | ‐ | |
| 912 per 1000 | 937 per 1000 (704 to 990) | |||||
| 10% CP versus 16% CP ‐ 2‐year follow‐up (higher shade indicates whiter) | The mean after intervention in 10% CP group was ‐81 | Mean difference in shade change was 1.20 higher in 16% CP group (0.35 lower to 2.75 higher) | ‐ | 81 (1 RCT) | ⊕⊝⊝⊝ VERY LOW1, 2 | ‐ |
| 16% CP versus 16% CP + ACP ‐ 6 months (higher shade indicates whiter) | The mean change in 16% CP group was ‐5.45 | Mean difference in shade change was 0.78 higher in 16% CP + ACP group (0.37 higher to 1.19 higher) | ‐ | 27 (1 RCT) | ⊕⊕⊝⊝ LOW2 | ‐ |
| 5% CP versus 10% CP ‐ 2 weeks (higher shade indicates whiter) | The mean after intervention for 10% CP group was ‐76.813 | Mean difference in shade change was 0.41 higher in 5% CP group (2.17 lower to 2.98 higher) | ‐ | 21 (1 RCT) | ⊕⊝⊝⊝ VERY LOW1, 2 | ‐ |
| 10% CP versus 15% CP ‐ 2 weeks (higher shade indicates whiter) | ‐ | Mean difference was 2.22 higher in 15% CP group (1.29 higher to 3.15 higher) | ‐ | 25 (1 RCT) | ⊕⊝⊝⊝ VERY LOW1, 2 | ‐ |
| 10% CP versus 10% CP + KN + NaF ‐ 2 weeks | ‐ | Standardised mean difference was 0.32 higher in 10% CP + KN + NaF group (0.20 lower to 0.84 higher) | ‐ | 58 (2 RCTs) | ⊕⊝⊝⊝ VERY LOW1, 2 | ‐ |
| Tooth whitening ‐ reported by the patient | ||||||
| 10% CP versus 17% CP ‐ 3 weeks (higher shade indicates whiter) | The mean change in shade for 10% CP group was ‐14.10 | Mean difference in patient contentment was 2.6 higher in 17% CP group (2.57 higher to 2.63 higher) | ‐ | 20 (1 RCT) | ⊕⊝⊝⊝ VERY LOW1, 2 | ‐ |
| Adverse effects | ||||||
| Higher concentrations of CP in tray led to more tooth sensitivity and gingival irritation. However, the symptoms were mild and transient. CP in tray with desensitiser showed significantly less sensitivity compared to the groups without the desensitiser | ||||||
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI) ACP: amorphous calcium phosphate; CI: confidence interval; KN: potassium nitrate; NaF: sodium fluoride; RCT: randomised controlled trial; RR: risk ratio | ||||||
| GRADE Working Group grades of evidence High certainty: we are very confident that the true effect lies close to that of the estimate of the effect Moderate certainty: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different Low certainty: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect Very low certainty: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect | ||||||
1Downgraded for risk of bias ‐ unclear risk of bias due to lack of allocation concealment. 2 Downgraded for imprecision ‐ low sample size and event rate.