A question that is increasingly common in orthodontic clinics is: “Can I undergo bleaching before getting braces?” For many adult patients, dental aesthetics are not only about tooth alignment but also tooth color. They want a straighter and brighter smile, and ideally, they want to achieve both in a single visit if possible. The challenge is that bleaching procedures are known to weaken the bond between orthodontic brackets and tooth enamel, creating clinical concerns that have remained unresolved.
A recent study from the Department of Orthodontics, Faculty of Dentistry, Universitas Gadjah Mada, offers findings that may change this perspective.
When Teeth Whitening Weakens the Foundation of Bonding
The bleaching process works through a chemical mechanism: hydrogen peroxide breaks down chromophore molecules responsible for tooth discoloration through oxidation-reduction reactions. As a result, teeth become lighter in color. However, residual free radicals remaining on the enamel surface after the procedure do not disappear immediately. These radicals are the main cause of reduced bracket adhesion strength.
In the control group of this study, ceramic brackets placed immediately after bleaching without additional treatment produced a shear bond strength (SBS) value of 6.32 MPa. This value was still within the clinically acceptable range according to Reynolds’ standard of 5.9–7.8 MPa, but the large standard deviation (±4.83 MPa) indicated considerable instability in the bonding strength. Scanning electron microscope (SEM) observations supported these findings. The enamel surfaces in the control group appeared to have large crater-like porosities surrounded by thin and irregular enamel prism structures.
Desensitizing Agents as a Solution for Restoring Bond Strength
Dr. drg. Dyah Karunia, Sp.Ort., together with a research team consisting of Muhammad Haikal Mahardhika, Prof. Pinandi Sri Pudyani, and Dr. drg. Ananto Ali Alhasyimi, investigated whether applying desensitizing agents immediately after bleaching could restore enamel conditions and strengthen ceramic bracket adhesion.
Two types of desensitizing agents were evaluated: CPP-ACFP (casein phosphopeptide-amorphous calcium phosphate fluoride), containing fluoride and CPP-ACP (casein phosphopeptide-amorphous calcium phosphate), fluoride-free. Both agents were applied for three minutes on enamel surfaces that had recently undergone bleaching with 37% hydrogen peroxide, before ceramic brackets were bonded using composite resin.
The results were surprisingly positive.
“The application of desensitizing agents containing fluoride or those without fluoride increases the shear bond strength of ceramic brackets on previously bleached teeth.”
The CPP-ACFP group recorded the highest SBS value at 15.36 MPa, while the CPP-ACP group reached 12.19 MPa. Both values were significantly higher than the control group, and the difference between the two desensitizing agents was not statistically significant. This means that both fluoride-containing and fluoride-free agents provided comparable benefits in this clinical context.
The mechanism can be explained through remineralization. Desensitizing agents supply calcium and phosphate ions to degraded enamel surfaces, restoring microstructure and filling the porosities created during the bleaching process. SEM images from both treatment groups showed shallower pores and more organized enamel prism structures compared with the control group.
Balancing Bond Strength and Debonding Risks
These findings have important clinical implications from two perspectives. On one hand, increased SBS means that brackets are more resistant to masticatory forces and orthodontic pressure. On the other hand, SBS values exceeding the recommended clinical range—such as the fluoride group reaching 15.36 MPa—may make bracket removal more difficult at the end of treatment and potentially increase the risk of enamel fracture.
The adhesive remnant index (ARI) assessment showed no significant differences among the three groups. The highest ARI score in each group was 4, meaning that less than 10% of adhesive residue remained on the enamel surface after bracket removal. This indicates that bond failure occurred at the enamel-adhesive interface rather than within the enamel structure itself. Clinically, this is more favorable because it facilitates adhesive removal and minimizes surface damage.
In other words, proper debonding techniques remain a critical factor in preventing enamel injury, regardless of how strong the bond becomes.
One Visit, Two Goals
Published in the journal Applied Sciences (MDPI) in July 2023, this study opens new possibilities for orthodontic practice: patients who wish to undergo bleaching and bracket placement during the same appointment may no longer need to wait one to three weeks, as previously recommended, provided that a desensitizing agent is applied between the two procedures.
Nevertheless, this study was conducted in vitro using extracted premolar teeth. Therefore, actual oral conditions—including the role of saliva and individual biological variations—are not fully represented. Clinical trials involving living patients are still required before this protocol can be widely adopted.
However, for patients sitting in the orthodontic chair hoping to leave with a brighter and straighter smile, this research provides evidence that such expectations may no longer be an overly ambitious dream.
Source DOI: https://doi.org/10.3390/app13148351
Authors: Nanda Ayu; drg. Achmad Zam Zam Aghasy, M.Kes.
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