Efficacy of Dental Bleaching with Whitening Dentifrices: A Systematic Review (2024)

Abstract

A systematic review was performed to evaluate whether whitening toothpastes promote tooth whitening when compared to the use of conventional (nonbleaching) dentifrices. This review was registered at PROSPERO (CRD42017065132) and is based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Electronic systematic searches of PubMed/MEDLINE, Scopus, and the Cochrane Library were conducted for published articles. Only randomized clinical trials in adults that compared the use of so-called whitening dentifrices to the use of nonwhitening dentifrices were selected. The outcome was tooth color change. Twenty-two articles from 703 data sources met the eligibility criteria. After title and abstract screening, 16 studies remained, after which a further five studies were excluded. In total, nine studies were qualitatively analyzed. Significant differences in tooth color change were found between the groups using whitening dentifrices and those using nonwhitening dentifrices. Within the limitations of this study, the evidence from this systematic review suggests that bleaching dentifrices have potential in tooth whitening. However, although many whitening dentifrices have been introduced into the dental market for bleaching treatments, it is important to analyze tooth surface and color changes when performing home bleaching.

1. Introduction

Tooth discoloration is one of the most commonly reported complaints in patients seeking aesthetic treatment. Variation in tooth color can be influenced by intrinsic and extrinsic factors, ranging from chemical ingestion to consumption of foods that cause staining [1, 2].

Currently, there are several products on the market that remove stains and claim to whiten teeth. Options range from simple professional prophylaxis and the application of bleaching gels to vital teeth for home use or supervised in a dental office [3]. Bleaching gels normally consist of different concentrations of hydrogen peroxide or carbamide peroxide and involve various forms of application. Furthermore, these different applications result in different mechanisms of activation, which provide dental bleaching through oxi-reduction reactions, based on partial oxidation of the active principle, through which the whitening agent alters the structure of pigment molecules, thus promoting tooth whitening [4, 5].

Several companies have developed bleaching toothpastes, which are considered an alternative to home and/or dental whitening procedures, and which promise bleaching results within 2 to 4 weeks. These toothpastes thus offer increasingly simpler and less costly bleaching methods for those wishing to have whiter teeth [6, 7]. Many of these bleaching toothpastes contain hydrogen peroxide, whereas others contain abrasive components, which promote the removal of extrinsic stains [7, 8].

These abrasives may remove blemishes from the coronary surfaces, giving rise to the idea that alterations in tooth coloration have occurred, which is often used as a marketing strategy by companies to show that teeth are healthy. However, little is known about the efficacy of these bleaching dentifrices compared with conventional (nonbleaching) dentifrices and their effects/alterations on stained teeth regardless of etiology [7, 9, 10].

Therefore, the objective of this systematic review was to evaluate whether whitening toothpastes promote tooth whitening when compared to the use of nonbleaching dentifrices. The hypothesis of the study is that bleaching dentifrices do not promote tooth whitening.

2. Materials and Methods

3. Results

The database search identified a total of 703 articles, 287 of which were from PubMed/MEDLINE, 303 from Scopus, and 113 from the Cochrane Library. After removal of duplicate references and a thorough review of titles and abstracts, 16 studies were read in full. After reading, nine studies were excluded (Table 1). Details regarding the search strategy are presented in the flow diagram (Figure 1).

In total, seven studies were selected for qualitative analyses and are summarized in Table 2. All selected studies were RCTs published between 2001 and 2016. A total of 1,399 patients with a mean age of 36.89 years were included in the studies, of which 879 used some type of dentifrice considered to be a bleaching agent by the manufacturer. The groups of patients evaluated varied according to the dentifrice, and the effectiveness of nine products was tested: Arm & Hammer® Advance White® Extreme Whitening Baking Soda and Peroxide Toothpaste (n=86), Arm & Hammer® Truly Radiant Toothpaste (n=59), Crest® 3-D white radiant mint toothpaste (n=56), Crest® Extra whitening (n=363), Colgate® Simple White® Advanced Whitening Toothpaste Sparkling Mint (n=21), Colgate® Baking Soda Peroxide (n=216), Colgate Luminous White® (n=32), Close-Up White Now® (n=31), and Oral B 3D white (n=15).

The bleaching effectiveness of the studied dentifrices was evaluated. Four studies showed that the products evaluated were effective in bleaching teeth using the VITA color scale (subjective method), and three studies showed that the products were effective in bleaching teeth using spectrophotometry (objective method).

In relation to daily brushing frequency, most studies [20–24] reported that using toothpaste twice a day increased tooth whitening, but two studies indicated that patients who brushed three times a day were more likely to have whiter teeth. In addition, the follow-up period ranged from 5 days to 8 weeks, with the most common period being 4 weeks (six studies). All studies included in this review examined subjects who used conventional toothpaste (not considered to have a bleaching effect by the manufacturers) as the control group.

The relevance of the articles included in this systematic review was considered satisfactory as all studies were RCTs with a low risk of bias (Figure 2). We included Cochrane randomized clinical trial studies to determine the bias scale in each study. All included studies were characterized as double-blind (randomized studies were performed with the patient and the evaluator blinded to the product), which is considered important in understanding responses in experimental clinical research.

4. Discussion

The results of this systematic review indicate that most of the included studies showed a significant change in dental coloration following the use of commercially available bleaching dentifrice agents when used for a period of between 5 days and 8 weeks.

Although peroxide bleaching materials are well-established for aesthetic tooth whitening, the use of these substances in dentifrices is quite limited [25]. In addition to causing alterations in products, high concentrations of hydrogen peroxide need to be counterbalanced by the use of soft tissue protective barriers in order to maintain contact with dental surfaces, which is not the case with bleaching toothpastes [8].

However, Isaacs et al. [21], Kakar et al. [22], and Ghassemi et al. [23] observed that the presence of 1.0% hydrogen peroxide in the chemical formulation of dentifrices caused tooth coloration changes when compared with nonwhitening toothpastes. These findings agreed with those obtained by Sharma et al. [17] who demonstrated the bleaching potential of these dentifrices and concluded that the presence of hydrogen peroxide was able to significantly interfere with dental chromatic alterations over a brushing period of 2 to 6 weeks. Therefore, it is important to consider the concentration of hydrogen peroxide and its contact time as important contributors to effective tooth whitening [19].

On the other hand, studies by Gerlach et al. [20], Horn et al. [25], and Ghassemi et al. [24] tested bleaching dentifrices that were free from any type of peroxide and obtained satisfactory results regarding changes in tooth coloration during the use of these toothpastes. These results may have been due to the presence of high performance abrasive agents contained in the bleaching dentifrices such as silica, which was present in almost all products included in this review [7, 21–25]. These abrasive agents promote the gradual physical removal of extrinsic pigments without effectively whitening teeth. Therefore, these bleaching dentifrices are sometimes considered only as surface spot removers [7, 8, 25].

Interestingly, the studies by Hilgenberg et al. [26] and Özkan et al. [27] showed that bleaching dentifrices promoted morphological changes on the surfaces of tooth enamel. Therefore, it is important to consider that brushing with toothpastes containing abrasive substances should be done with caution, as the indiscriminate use of dentifrices with large quantities of these agents can lead to irreversible damage of hard dental tissues and restorative materials; they can also lead to recession of the gingiva, abrasion in the cervical region, and in some cases, dentin hypersensitivity [8, 26].

Another limiting factor is that these studies did not use similar evaluation methods, making it difficult to compare the parameters studied in the coloration change analyses in this review. Dozic et al. [28] proposed that the spectrophotometer was the most reliable instrument on the market for tooth coloration analysis; the accuracy of the results is related to the positioning of the equipment at the same point of the dental surface at all times of analysis [14].

However, among the studies selected in this review which used spectrophotometry as the evaluation method, only the study by Isaacs et al. [21] demonstrated a significant color change following use of the bleaching dentifrices. This probably occurred because the products tested by Isaacs et al. [21] contained hydrogen peroxide associated with a high performance silica. These results are in agreement with those by Sharma et al. [17], who confirmed that these two substances in a dentifrice were able to remove extrinsic stains, reducing the yellow color pigmentation (b^∗ parameter) of the teeth, when compared to conventional dentifrices.

The findings of Horn et al. [25] and Pintado-Palomino et al. [7], who also used spectrophotometry as a method of evaluation, did not show a significant difference between bleaching and conventional dentifrices, a factor justified by the absence of hydrogen peroxide in the dentifrices tested. Although in the study by Horn et al. [25], a statistical difference was shown in one of the test groups (Colgate Luminous White dentifrice) by altering the values of L^∗ (brightness), it was also seen that according to the NBS criterion, the value of ΔE was 1.15, which meant a change in color was not perceived by the human eye. This change in luminosity probably occurred due to the presence of abrasive contents in this dentifrice, such as hydrated silica.

The four studies that used the VITA shade guide observed a statistically significant difference between the test and control groups. These favorable findings may have been attributed to the method used to analyze the color on the total surface of the tooth, without taking into account specific points [14].

The limitations of the present systematic review include the following: the lack of clinical studies using the same method to evaluate the color of dental substrates, in order to allow a comparison of the parameters included in the data analysis; the lack of studies that took into account the durability of color change following discontinuation of the bleaching dentifrices; and the studies did not take into account the frequency of brushing with bleaching dentifrices, as brushing time can influence color change^. [7]. Thus, future studies are necessary in order to investigate characteristics such as morphological alterations of the dental surface caused by dentifrice materials, in order to establish an effective time-of-use protocol, the influence of dentifrice components on whitening properties, and the durability of tooth whitening after whitening toothpaste is discontinued.

5. Conclusions

Within the limitations of this study, the evidence from this systematic review suggested that bleaching dentifrices have potential in tooth whitening. However, these results should be interpreted with caution before any decision is made, and more randomized clinical trials are required to better determine the efficacy of bleaching dentifrices due to their possible morphological alterations of dental tissues.

Conflicts of Interest

The authors declare that there are no conflicts of interest regarding the publication of this paper.

References