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.
AUTHORS' CONCLUSIONS: We found low to very low-certainty evidence over short time periods to support the effectiveness of home-based chemically-induced bleaching methods compared to placebo for all the outcomes tested.We were unable to draw any conclusions regarding the superiority of home-based bleaching compositions or any particular method of application or concentration or application time or duration of use, as the overall evidence generated was of very low certainty. Well-planned RCTs need to be conducted by standardising methods of application, concentrations, application times, and duration of treatment.
MATERIALS AND METHODS: Thirty-five inbred female Sprague Dawley rats aged 43 days were administered with three weekly doses of N-methyl-N-nitrosourea (NMU) intraperitoneally (ip) at 50 mg/kg body weight. Animals were randomized (beginning from 10 mm tumor size) into four TAM-treated (50, 100, 200 and 500 μg/day) groups of six animals each, and another group (n=6) treated with TAM 100 μg/day at starting tumour size of 15 mm. The animals were treated by oral gavage daily for 8 weeks before sacrifice.
RESULTS: Serum urea and creatinine, and overall physical tumor burden were significantly modulated in animals treated with variable doses of TAM compared to the untreated controls (n=5). Final body weight and tumor number were significantly different in the 10 mm-treated animals compared to those treated at 15 mm. There were no significant differences in histopathological features among all the groups.
CONCLUSIONS: Our findings suggest the importance of standardizing tumour size and drug doses before initiation of treatment, particularly in the direct comparison of basic end-tumour physical parameters.