I. Izquierdo-Barba, C. Torres-Rodríguez, E. Matesanz, M. Vallet-Regí
Context
- Dental bleaching is commonly carried out to correct discolouration of anterior teeth. Most bleaching agents are strong oxidizing agents and the most popular bleaching agent includes hydrogen peroxide (1).
- Although this bleaching agent is highly effective in lightening tooth colour, concerns have been expressed regarding to associated post-bleaching complications including alteration in the surface morphology of enamel and dentin, change in its chemical composition, increase in its permeability, and notable changes in its mechanical properties (2, 3).
- There is a strong necessity to develop a different approach to determine the real consequences of bleaching treatment by using an unchangeable and entire tooth.
- The environmental scanning electron microscopy, the electron probe micro analyzer and X-ray diffraction techniques have been used to evaluate the effects of 38% (p/v) hydrogen peroxide treatment onto morphological, chemical and structural features in the human enamel and dentin.
- Although such effects have been widely investigated with several techniques, including XRD and SEM, the novelty of this study lies in the techniques and methodology used to characterize the human teeth after bleaching treatment.
- This approach allows to carry out the analyses without any previous pretreatment, such as powdering, dried or metal sputtering, and its study in the same tooth piece before and after bleaching, which avoids the possible intrinsic differences derived from the use of different pieces.
Purpose of the Study
- To determine the effects of dental bleaching with H2O2 38% (w/v) during 20 min on the morphological, chemical and structural features of human molar teeth.
Key Findings
- Neither the structural nor the chemical features of enamel and dentin are altered after bleaching treatment.
- Nonetheless, the morphology of the enamel is notably altered, with the appearance of channels with very pronounced pores. These channels could make enamel more susceptible to bacterial attack.
- The major scientific relevance of this study relies on the techniques and methodology used to deeply characterize the teeth after bleaching treatment, putting an end to the controversies on the different effects found in the literature, and setting novel standard protocols for future studies.
References
List of references included in the study (PDF)
So, what are the conclusions. If the enamel is more susceptible to bacterial attack, should we suggest F- after treatments? How long are these ‘channels’ and ‘porosities’ detectable before the enamel remineralizes?
Are the answers to these questions in the article that will be published in February?
No ‘chemical feature’ changes to dentin? Enamel is crystal clear. It has no colour unless it is stained on the surface from tea, smoking etc. Dentin has a yellow colour: e.g. A1 to A4 (the older, or thicker the dentin, the darker the tooth). To ‘whiten’ teeth you have to break the double bonds of the organic molecules in dentin that give dentin its colour. Vital bleach provides the free radicals that break double bonds. I’m sorry, but there ARE changes to the chemical features of dentin. You can visually SEE the changes.
I agree with Hardy. these results are surprising. I couldn’t find the article on-line. It is prudent for CDA to make such articles available to the readership so we can assess their scientific basis and the validity of their conclusions. I look forward to reading it when it’s available.
Here,here!
We should have the option to read for ourselves.
Hello Dr. Nouri,
Thank you for taking the time to comment on the post. You mention not being able to find the article online and it may be because it requires a subscription to the journal. However, the abstract is available under the journal homepage at this URL: http://www.sciencedirect.com/science/article/pii/S0167577X14021235
The intent of all our posts is to provide clinicians with the research/information that is available in the hope of opening up conversations among dentists. We do not inlcude our own opinions or perspectives.
Please keep sharing your feedback with us, it is most helpful. And, should you have any question, suggestion, or comment that you would like to send us directly, please do not hesitate to contact me at oasisdiscussions@cda-adc.ca
Chiraz
JCDA Oasis Team