Home teeth whitening kits have become very popular with people who want faster whitening of teeth and who cannot visit the dentist. A Study performed by researchers at the University of Toronto have published in Nature Scientific Reports, the harmful effects of Home teeth whitening kits available in the market.

The study has concentrated on the damage to cells caused by the use of a specific Teeth Whitening agent – Carbamide Peroxide (Commonly used in Teeth whitening in concentrations of 10% and 35%).  According to the research it was found that, on application of 10% Carbamide peroxide lead to 50 percent loss of Enamel content. The study used Commercial carbamide peroxide concentrations of 5%, 10%, 16% and 35%.

Enamel being the outermost layer of the tooth and being the strongest part of the tooth is the one which will be taking the full brunt of the Whitening agent. So the study was aimed at the effect of the whitening agent on the Enamel and the Pulp. The thought of the damage done by the Carbamide Peroxide to the pulp tissue arise after he observed the damage Hydrogen Peroxide was causing on the collagen tissue in the Pulp chamber during irrigation in Root canal treatment.

With the effect of Carbamide peroxide on the Enamel protein, it resulted in penetration of the whitening agent in to the tooth coming in contact with the pulp tissue, leading to pulp cell mortality. This was observed by using an in-house dentine perfusion chamber, by infusing the pulp cells with 35% Carbamide peroxide it was observed that the pulp tissue did not survive the exposure.

Harmful effects of home teeth whitening kits

Source: https://www.nature.com/articles/s41598-021-94745-w/figures/3

Conclusion from the Study:

CP concentrations of 5% and 16% induced 50% reduction of the weight of organic content of Enamel making it porous and susceptible to Peroxide diffusion and come in contact with the Dentin or Pulp tissue. Concentrations of 35% CP gel applied for 4 hours lead to producing intense oxidative stress on both gingival fibroblast and pulp cells. Based on these findings it is clear that using 5% concentration of CP gel can be less harmful to dental cellas and should be recommended in Home Teeth whitening kits, higher concentration kits should be used only in a controlled environment by a trained professional to avoid any permanent damage to the tooth structure.

With such high concentrations of Carbamide peroxide (35%) teeth whitening  agents available openly in the market for personal use, it can be more harmful to the tooth than beneficial. In the hands of trained Dental professionals it can give the desired effects but on personal use the patient tends to over expose their teeth with the agent leading to a non vital tooth.

In a Dental clinic environment these factors are checked and adequately monitored – Concentration of the Peroxide, Exposure time, desired shade change and maintaining gap between appointments. So in the future either peroxide agents with controlled release or non peroxide agents should be used for At Home tooth whitening kits.

Bozec notes that the study, which included contributions from Boris Hinz, a distinguished professor at the Faculty of Dentistry, involved an international collaboration and the involvement students in the doctor of dental surgery program. They included Sabrina Nguyen and Ola Redha, a visiting PhD student from University College London.

“I worked with Professor Bozec previously at UCL for the last seven years and was fortunate to have him invite me to work on and complete this project here at the Faculty of Dentistry,” says Redha.

“It’s been fascinating to undertake research at the highest level at both U.K. and Canadian universities.”

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