Introduction EU council directive 2011/84/EU resulted in a demand for over the counter (OTC) bleaching products. The industry has latched onto this renewed demand by developing a range of non-hydrogen peroxide OTC products. Aims To determine whether non-hydrogen peroxide OTC whitening products available in the UK are safe and to determine the lightening effect of those products. Materials and methods A total of 21 extracted teeth (11 incisors and ten premolars) were collected and stored in chloramine-T solution. Five days before the study, all teeth were immersed in 5 ml of a standard green tea solution at room temperature (22±2 °C). Roots were sectioned from the teeth and cleaned using an ultrasonic bath. Teeth were then embedded in epoxy resin and sectioned inciso-gingivally to serve as paired test and control specimens. A positive control of 10% carbamide peroxide was used while saline was used as a negative control. Five OTC products were selected from two major British consumer outlets. Initially, products were applied to the teeth samples for two one-hour cycles, followed by the equivalent of one-week's application, according to the manufacturer's instruction. Samples were stored overnight in saline to minimise any effects of dehydration. Shades of teeth were taken blindly by a single trained clinician in a natural light environment against a grey background before and after application of the products. Vickers microhardness tests and scanning electron microscopy (SEM) analysis were undertaken. Results SEM analysis showed surface morphology alterations to varying degrees, with several samples demonstrating a distinct etching pattern post-exposure to the OTC products. Sample three ('Brilliant 5 minute kit') and sample five ('iWhite instant teeth whitening') produced the most extensive surface alterations. Samples three and five also resulted in a significant reduction (p = 0.008) in Vickers microhardness. Two OTC products resulted in a lightening effect less than the negative control saline, whereas two other OTC products resulted in a lightening effect greater than carbamide peroxide. Conclusion This study suggests that non-hydrogen peroxide OTC products have the potential to damage enamel and lighten teeth. The lightening effect of the OTC products is variable, however, it is most likely to occur in sodium chlorite based products.
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National Institute of Teeth Whitening. Teeth Whitening Industry's Annual Revenue in 2015 Totals $11 Billion. 2015.
Haywood V B, Heymann H O. Nightguard vital bleaching. Quintessence Int 1989; 20: 173-176.
Li Y, Greenwall L. Safety issues of tooth whitening using peroxide-based materials. Br Dent J 2013; 215: 29-34.
European Union. EU Council Directive 2011/84/EU of 20 September 2011. Available at https://eur-lex.europa.eu/riServ/LexUriServ.do?uri=OJ:L:2011:283:0036:0038:en:PDF (accessed January 2019).
Joiner A. Whitening toothpastes: a review of the literature. J Dent 2010; 38: e17-e24.
Kwon S R, Meharry M, Oyoyo U, Li Y. Efficacy of doityourself whitening as compared to conventional tooth whitening modalities: an in vitro study. Oper Dent 2015; 40: E21-E27.
Sulieman M, Addy M, Rees J S. Development and evaluation of a method in vitro to study the effectiveness of tooth bleaching. J Dent 2003; 31: 415-422.
Soares D G, Basso F G, Pontes E C, da F R Garcia L, Hebling J, de Souza Costa C A. Effective tooth-bleaching protocols capable of reducing H2O2 diffusion through enamel and dentine. J Dent 2014; 42: 351-358.
Polydorou O, Hellwig E, Hahn P. The efficacy of three different in-office bleaching systems and their effect on enamel microhardness. Oper Dent 2008; 33: 579-586.
Ristic I, Stankovic S, Paravina R D. Influence of color education and training on shade matching skills. J Esthet Restor Dent 2016; 28: 287-294.
Haywood V B, Leonard R H, Dickinson G L. Efficacy of six-months nightguard vital bleaching of tetracycline-stained teeth. J Esthet Dent 1997; 9: 13-19.
Bitter N C. A scanning electron microscope study of the long-term effect of bleaching agents on the enamel surface in vivo. Gen Dent 1998; 46: 84-88.
Potocnik I, Kosec L, Gaspersic D. Effect of 10% carbamide peroxide bleaching gel on enamel microhardness, microstructure, and mineral content. J Endod 2000; 26: 203-206.
White D J, Kozak K M, Zoladz J R, Duschner H, Götz H. Peroxide interactions with hard tissues: effects on surface hardness and surface/subsurface ultrastructural properties. Compend Contin Educ Dent 2002; 23: 42-48.
Lopes G C, Bonissoni L, Baratieri L N, Vieira L C, Monteiro S Jr. Effect of bleaching agents on the hardness and morphology of enamel. J Esthet Restor Dent 2002; 14: 24-30.
Attin T, Schmidlin P R, Wegehaupt F, Wiegand A. Influence of study design on the impact of bleaching agents on dental enamel microhardness: a review. Dent Mater 2009; 25: 143-157.
Berger S B, Cavalli V, Martin A A et al. Effects of combined use of light irradiation and 35% hydrogen peroxide for dental bleaching on human enamel mineral content. Photomed Laser Surg 2010; 28: 533-538.
Li Q, Xu B T, Li R, Yu H, Wang Y N. Quantitative evaluation of colour regression and mineral content change of bleached teeth. J Dent 2010; 38: 253-260.
Justino L M, Tames D R, Demarco F F. In situ and in vitro effects of bleaching with carbamide peroxide on human enamel. Oper Dent 2004; 29: 219-225.
Sun L, Liang S, Sa Y et al. Surface alteration of human tooth enamel subjected to acidic and neutral 30% hydrogen peroxide. J Dent 2011; 39: 686-692.
Mokhlis G R, Matis B A, Cochran M A, Eckert G J. A clinical evaluation of carbamide peroxide and hydrogen peroxide whitening agents during daytime use. J Am Dent Assoc 2000; 131: 1269-1277.
Leonard R H Jr, Bentley C, Eagle J C, Garland G E, Knight M C, Phillips C. Nightguard vital bleaching: a long-term study on efficacy, shade retention, side effects, and patients' perceptions. J Esthet Restor Dent 2001; 13: 357-369.
Matis B A, Mousa H N, Cochran M A, Eckert G J. Clinical evaluation of bleaching agents of different concentrations. Quintessence Int 2000; 31: 303-310.
Matis B A, Cochran M A, Eckert G, Carlson T J. The efficacy and safety of a 10% carbamide peroxide bleaching gel. Quintessence Int 1998; 29: 555-563.
Al Shethri S, Matis B A, Cochran M A, Zekonis R, Stropes M. A clinical evaluation of two in-office bleaching products. Oper Dent 2003; 28: 488-495.
Bentley C D, Leonard R H, Crawford J J. Effect of whitening agents containing carbamide peroxide on cariogenic bacteria. J Esthet Dent 2000; 12: 33-37.
Yao C S, Waterfield J D, Shen Y, Haapasalo M, MacEntee M I. In vitro antibacterial effect of carbamide peroxide on oral biolfilm. J Oral Microbiol 2013; 5: DOI: 10.3402/jom.v5i0.20392.
Leonard R H Jr, Bentley C D, Van Haywood B. Salivary pH changes during 10% carbamide peroxide bleaching. Quintessence Int 1994; 25: 547−550.
Almas K, Al-Harbi M, Al-Gunaim M. The effect of a 10 percent carbamide peroxide home bleaching system on the gingival health. J Contemp Dent Pract 2003; 4: 32−41.
Brunton P A, Ellwood R, Davies R. A six-month study of two self-applied tooth whitening products containing carbamide peroxide. Oper Dent 2004; 29: 623−626.
Greenwall L. The dangers of chlorine dioxide tooth bleaching. Aesth Dent Today 2008; 2: 21-23.
Zantner C, Beheim-Schwarzbach N, Neumann K, Kielbassa A M. Surface microhardness of enamel after different home bleaching procedures. Dent Mater 2007; 23: 243-250.
Ablal M A, Adeyemi A A, Jarad F D. The whitening effect of chlorine dioxide: an in vitro study. J Dent 2013; 41 (Spec Iss): e76-e81.
Lussi A, Jaeggi T, Jaeggi-Schärer S. Prediction of the erosive potential of some beverages. Caries Res 1995; 29: 349-354.
West N X, Hughes J A, Addy M. The effect of pH on the erosion of dentine and enamel by dietary acids in vitro. J Oral Rehab 2001; 28: 860-864.
Hughes J A, West N X, Parker D M, van den Braak M H, Addy M. Effects of pH and concentration of citric, malic and lactic acids on enamel, in vitro. J Dent 2000; 28: 147-152.
Eisenburger M, Addy M. Evaluation of pH and erosion time on demineralisation. Clin Oral Investig 2001; 5: 108-111.
Barbour M E, Parker D M, Jandt K D. Enamel dissolution as a function of solution degree of saturation with respect to hydroxyapatite: a nanoindentation study. J Colloid Interface Sci 2003; 265: 9-14.
Eisenburger M, Addy M, Hughes J A, Shellis R P. Effect of time on the remineralisation of enamel by synthetic saliva after citric acid erosion. Caries Res 2001; 35: 211-215.
Ionta F Q, Mendonça F L, de Oliveira G C et al. In vitro assessment of artificial saliva formulations on initial enamel erosion remineralization. J Dent 2014; 42: 175-179.
Tam L. Effect of potassium nitrate and fluoride on carbamide peroxide bleaching. Quintessence Int 2001; 32: 766-770.
Gerlach R W, Gibb R D, Sagel P A. A randomized clinical trial comparing a novel 5.3% hydrogen peroxide whitening strip to 10%, 15%, and 20% carbamide peroxide tray-based bleaching systems. Compend Contin Educ Dent Suppl 2000; 29 (Spec Iss): S22-S28.
Ferrari M, Cagidiaco M C, Monticelli F, Kugel G, Barker M L, Gerlach R W. Daytime use of a custom bleaching tray or whitening strips: initial and sustained colour improvement. Am J Dent 2007; 20 (Spec Iss): 19A-22A.
Greenwall L H (ed). Tooth whitening techniques. 2nd ed. London: Taylor and Francis, 2017.
Hosoya N, Honda K, Iino F, Arai T. Changes in enamel surface roughness and adhesion of Streptococcus mutans to enamel after vital bleaching. J Dent 2003; 31: 543-548.
Quirynen M, Bollen C M. The influence of surface roughness and surface-free energy on supra-and subgingival plaque formation in man. A review of the literature. J Clin Periodontol 1995; 22: 1-14.
Cavalli V, Arrais C A, Giannini M, Ambrosano G M. High-concentrated carbamide peroxide bleaching agents effects on enamel surface. J Oral Rehabil 2004; 31: 155-159.
Mccaslin A J, Haywood V B, Potter B J, Dickinson G L, Russell C M. Assessing dentin colour changes from nightguard vital bleaching. J Am Dent Assoc 1999; 130: 1485-1490.
Frei M Y, Nielsen S, Dobbin M D, Tobin C L. Serious morbidity associated with misuse of overthecounter codeine-ibuprofen analgesics: a series of 27 cases. Med J Aust 2010; 193: 294-296.
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Cite this article
Greenwall-Cohen, J., Francois, P., Silikas, N. et al. The safety and efficacy of 'over the counter' bleaching products in the UK. Br Dent J 226, 271–276 (2019). https://doi.org/10.1038/s41415-019-0011-6
- Describes the range of over the counter (OTC) bleaching products available in the UK.
- Suggests advice to give to patients with regards to OTC bleaching products.
- Improves understanding of core bleaching concepts and bleaching research.
Journal of Dentistry (2020)
BDJ Team (2019)
British Dental Journal (2019)