DESIGN: Following the PRISMA-ScR guidelines, three electronic databases were searched (Pubmed, Scopus and Web of Science).

RESULTS: A total of twelve studies were included in the final review that reported on small-animal (rats, guinea pigs, rabbits) and large-animal (dogs and goats) models. Based on the grafting biomaterials, eight papers used cell-free scaffolds, four articles utilised cell-based scaffolds. The timing protocol for the initiation of OTM employed in the studies ranged from immediate to 6 months after surgical grafting. Only four studies included autologous bone graft (gold standard) as positive control. Most papers reported positive results with regards to the rate of OTM and bone augmentation effects while only a few reported side effects such as root resorptions. Overall, the included articles showed a massive heterogeneity in terms of the animal bone defect model characteristics, scaffold materials, study designs, parameters of OTM and methods of analysis.

OBJECTIVES: To evaluate the effects of home-based tooth whitening products with chemical bleaching action, dispensed by a dentist or over-the-counter.

SEARCH METHODS: Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 12 June 2018), the Cochrane Central Register of Controlled Trials (CENTRAL; 2018, Issue 6) in the Cochrane Library (searched 12 June 2018), MEDLINE Ovid (1946 to 12 June 2018), and Embase Ovid (1980 to 12 June 2018). The US National Institutes of Health Ongoing Trials Register ClinicalTrials.gov (12 June 2018) and the World Health Organization International Clinical Trials Registry Platform (12 June 2018) were searched for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA: We included in our review randomised controlled trials (RCTs) which involved adults who were 18 years and above, and compared dentist-dispensed or over-the-counter tooth whitening (bleaching) products with placebo or other comparable products.Quasi-randomised trials, combination of in-office and home-based treatments, and home-based products having physical removal of stains were excluded.

DATA COLLECTION AND ANALYSIS: Two review authors independently selected trials. Two pairs of review authors independently extracted data and assessed risk of bias. We estimated risk ratios (RRs) for dichotomous data, and mean differences (MDs) or standardised mean difference (SMD) for continuous data, with 95% confidence intervals (CIs). We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS: We included 71 trials in the review with 26 studies (1398 participants) comparing a bleaching agent to placebo and 51 studies (2382 participants) comparing a bleaching agent to another bleaching agent. Two studies were at low overall risk of bias; two at high overall risk of bias; and the remaining 67 at unclear overall risk of bias.The bleaching agents (carbamide peroxide (CP) gel in tray, hydrogen peroxide (HP) gel in tray, HP strips, CP paint-on gel, HP paint-on gel, sodium hexametaphosphate (SHMP) chewing gum, sodium tripolyphosphate (STPP) chewing gum, and HP mouthwash) at different concentrations with varying application times whitened teeth compared to placebo over a short time period (from 2 weeks to 6 months), however the certainty of the evidence is low to very low.In trials comparing one bleaching agent to another, concentrations, application method and application times, and duration of use varied widely. Most of the comparisons were reported in single trials with small sample sizes and event rates and certainty of the evidence was assessed as low to very low. Therefore the evidence currently available is insufficient to draw reliable conclusions regarding the superiority of home-based bleaching compositions or any particular method of application or concentration or application time or duration of use.Tooth sensitivity and oral irritation were the most common side effects which were more prevalent with higher concentrations of active agents though the effects were mild and transient. Tooth whitening did not have any effect on oral health-related quality of life.

METHODS: Electronic database and hand search of English literature in PubMed, Cochrane Central Register of Controlled Trials, Embase, Web of Science, and clinical trial.gov, with author clarification were performed. The selection criteria were randomized controlled trial (RCT) comparing MOPs with conventional treatment involving both extraction and nonextraction. Cochrane's risk of bias tool and Grading of Recommendations Assessment, Development and Evaluation approach were used for quality assessment. Studies were analyzed with chi-square-based Q statistic methods, I2 index, fixed-effects, and random-effects model. Quantitative analysis was done on homogenous studies using Review Manager.

RESULTS: Eight RCTs were included for the qualitative analysis. Meta-analysis of 2 homogenous studies indicated insignificant effect with MOPs (0.01 mm less OTM; 95% CI, 0.13-0.11; P = 0.83). No difference (P >0.05) was found in anchorage loss, root resorption, gingival recession, and pain.

CONCLUSIONS: Meta-analysis of 2 low-risk of bias studies showed no effect with single application MOPs over a short observation period; however, the overall evidence was low. The quality of evidence for MOP side effects ranged from high to low. Future studies are suggested to investigate repeated MOPs effect over the entire treatment duration for different models of OTM and its related biological changes.