Sodium Perborate Tetrahydrate: Dental Bleaching Agent

Sodium perborate tetrahydrate is an inorganic peroxide. As a mild oxidizing agent and bleaching agent, it combines disinfecting, deodorizing, and stain-removing properties. With low corrosivity and good environmental compatibility, it is widely used in household cleaning, fabric bleaching, denture cleaning, and mild disinfection. It is also employed as a selective oxidizing agent in organic synthesis, as well as an electroplating aid and textile printing and dyeing aid. It is a widely used green oxygen-containing additive in the light industry and fine chemicals sectors.

Clinical efficacy of sodium perborate tetrahydrate

Tooth discolouration is the alteration in the color of a tooth which can either be extrinsic or intrinsic based on the aetiology and location of the stain. Agents that are commonly used include hydrogen peroxide, carbamide peroxide, and sodium perborate. Sodium perborate tetrahydrate in its usual powder form decomposes when damp to release nascent oxygen as the oxidizing radical. It is used by mixing with hydrogen peroxide or distilled water. The use of sodium perborate and hydrogen peroxide as a bleaching agent has been reported to be associated with side effects such as alteration of the micro hardness of the tooth structure and cervical root resorption. This is well observed when the etiology of loss of tooth vitality is trauma. The combined effect of alteration in the structure of the tooth by sodium perborate tetrahydrate and hydrogen peroxide requires the use of less destructive regimen like sodium perborate mixed with distilled water which has not been used as a tooth bleaching agent. However, there is a need for a study that will compare the effectiveness of sodium perborate mixed with distilled water and sodium perborate tetrahydrate mixed with hydrogen peroxide as non-vital anterior tooth bleaching agent, which this present study sought to do.[1]

After the non-vital bleaching, the mean tooth shade in teeth of participants in sodium perborate mixed with 30% peroxide and sodium perborate tetrahydrate mixed with distilled water groups decreased progressively to 3.1 and 4.0 at Day 21 respectively indicating that the change in tooth color became more pronounced as the days increased. These findings are in agreement with findings from previous studies. In this present study, the color change became more prominent at Days 14 and 21 in agreement with findings from previous studies in which desirable result was seen after two and three weeks of non-vital bleaching. The clinical implications are that it takes 14 days to achieve significant change in color and 21 days to achieve optimal change in treatment of discolored non-vital teeth. The effectiveness of sodium perborate tetrahydrate mixed with distilled water was similar to that of sodium perborate mixed with 30% hydrogen peroxide in the lightening of the coronal part of endodontically treated nonvital discoloured anterior teeth. Both bleaching agents demonstrated similar patient satisfaction. This implies that sodium perborate tetrahydrate mixed with distilled water is an alternative less expensive and more conservative treatment option for non-vital discoloured anterior teeth.

In vitro approach to assess the safety of oral care products

Oral care products like mouthwashes containing chlorhexidine, antibiofilm agents, carbamide peroxide, triclosan, essential oils and sodium perborate tetrahydrate are frequently used before surgery and dental procedures due to their antimicrobial properties. Sodium perborate tetrahydrate is especially prevalent due to its benefits, including its effective bleaching properties, its role as an antimicrobial agent, and its capacity to release oxygen, which aids in wound healing and tissue regeneration. However, concerns about its safety have arisen in studies, prompting uncertainty in the industry and among regulators about product registration, necessitating further tests and safety evaluations. This study assessed the cytotoxic effects of pure sodium perborate tetrahydrate and oral care products containing it, using various cell models—monolayer (2D), spheroids (3D), and RHE. These models were chosen to increase the relevance and reliability of the findings for in vivo conditions. Primary gingival fibroblasts and human epidermal keratinocytes were employed, closely mimicking oral mucosa, to assess cell viability and proliferation. The products tested are commercially available for both professionals and the public, and key tests adhered to OECD Test Guideline 439. The outcomes of this study are intended to inform safer product formulations and use in the oral care industry, highlighting potential health risks associated with cytotoxicity.[2]

Sodium perborate tetrahydrate releases hydrogen peroxide and nascent oxygen when it comes into contact with water (Mishra et al., 2020). This property has found its application in dental products for tooth whitening and post-treatment, utilizing the antiseptic and oxidizing characteristics of the produced compounds. However, there are concerns with sodium perborate tetrahydrate’s potential cytotoxic effects. Some in vitro studies have shown a dose-dependent decrease in epithelial cell viability upon exposure (Zhang et al., 2017). Our findings underscore the pivotal roles that exposure duration and chosen cell culture model play in in vitro toxicity determination. Specifically, while the tested products exhibited toxicity in monolayer cultures, they appeared non-toxic in three-dimensional (3D) models. Sodium perborate tetrahydrate, in concentrations below 0.1 mg/mL, demonstrated minimal toxicity across both models. Furthermore, when evaluated using the reconstituted epidermis in alignment with the OECD TG 439 criteria, the products were determined to be non-irritating to the 17-day-old epidermis, partially mimicking an oral mucosa. However, concerns about its safety have arisen in studies, prompting uncertainty in the industry and among regulators about product registration, necessitating further tests and safety evaluations.

Three Bleaching Agents on Tooth Discoloration

Successful outcome of pulp capping treatment using mineral trioxide aggregate (MTA), often leads to tooth discoloration. This study aimed to compare the efficacy of external bleaching technique with three bleaching agents naming hydrogen peroxide, carbamide peroxide and sodium perborate tetrahydrate for correction of tooth discoloration caused by MTA. No significant difference was noted in color change (∆E) immediately after bleaching with hydrogen peroxide and carbamide peroxide (P>0.05). However, these two groups had significant differences in ∆E with the sodium perborate group (P=0.001). Hydrogen peroxide group showed significantly higher ∆E at 1 week compared with other groups (P=0.01). The three groups were significantly different in ∆E at 2 weeks after bleaching (P=0.001). Pairwise comparisons revealed no significant difference between sodium perborate tetrahydrate and carbamide peroxide in ∆E but they both had a significant difference with hydrogen peroxide (P=0.01). The three bleaching agents bleached the discoloured teeth effectively. Hydrogen peroxide had the highest efficacy whilst sodium perborate tetrahydrate and carbamide peroxide had lower but similar efficacy.[3]

References

[1]Odofin AD, Taiwo J, Solanke IA, Ibiyemi O, Afolabi AO. A RANDOMISED CONTROLLED TRIAL ON CLINICAL EFFICACY OF SODIUM PERBORATE MIXED WITH DISTILLED WATER AND 30% HYDROGEN PEROXIDE IN THE LIGHTENING OF NON-VITAL DISCOLOURED ANTERIOR TEETH. Ann Ib Postgrad Med. 2023 Dec;21(3):39-45. Epub 2024 Jan 30. PMID: 38706621; PMCID: PMC11065194.

[2]Leano SM, De Souza W, De Vecchi R, Lopes A, Deliberador T, Granjeiro JM. A multimodal in vitro approach to assess the safety of oral care products using 2D and 3D cellular models. Front Toxicol. 2024 Nov 6;6:1474583. doi: 10.3389/ftox.2024.1474583. PMID: 39568718; PMCID: PMC11576945.

[3]Saati K, Sheikhi S, Esnaashari E, Valizadeh S. The Effects of Three Bleaching Agents on Tooth Discoloration Caused by Mineral Trioxide Aggregate. Iran Endod J. 2019 Fall;14(4):253-258. doi: 10.22037/iej.v14i4.23071. PMID: 36794102; PMCID: PMC9923412.