Evolution of Dental Bleaching, from research to clinical evidence

A clinical case by our Community member Dr. Rim Bourgi

This article and its content are published under the Author’s responsibility as an expression of the Author’s own ideas and practice. Styleitaliano denies any responsibility about the visual and written content of this work.

The search for whiter teeth has encouraged a growing use of bleaching agents. Patients are generally displeased with the color of their teeth. In an attempt to solve this problem and improve the shade of the teeth, dental bleaching treatment can be employed as a well-accepted, safe, efficient, and non-invasive procedure. This could be possible either by the dental practitioner using bleaching products with a high concentration of a bleaching agent, or by the patient dispensing a low concentration of bleaching agents into a custom-fit tray. The research for an ideal whitening agent has urged manufacturers to launch gels containing different concentrations of carbamide (CP) or hydrogen peroxide (HP) ranging from 5% to 40% HP and 10% to 35% CP. Despite these widespread uses, dentin hypersensitivity, gingival irritation, and alteration of tooth surface morphology can pose as potential side effects of the use of HP in dental office. At-home bleaching has gained popularity among these types of products. Several studies suggested that by using scanning electron microscopy (SEM), enamel structure could be weakened by oxidation of both organic and mineral elements. Nevertheless, the findings of these studies are opposing. In addition, a perfect smile and aesthetic demands by means of white and healthy teeth are now recommended. The use of mobile dental photography (MDP) with auxiliary lighting (Smile Lite MDP) can be achieved in several ways in dentistry including the evolution of the bleaching process. MDP allows both the dentist and the patient to visualize a clinical situation on a bigger scale, where details can be emphasized. How can a dentist document and choose the standard concentration when treating a tooth discoloration?

The aim of this article is to showcase the morphological changes of enamel surface using lower concentration of CP. In addition, documenting, using mobile photography, the progress of bleaching treatment is also an aim. This case is an attempt to translate the research to clinical evidence while improving the confident smile of the patients.

style italiano styleitaliano smileline mdp dental photography
style italiano styleitaliano smileline mdp dental photography
styleitaliano style italiano dark yellow teeth

Fig.1
A 29-year-old male visited our dental office and asked us to figure out a solution for his teeth discoloration issue, preferably avoiding the drilling approach. Patient was placed in occlusion before bleaching with cheek retractors.

styleitaliano style italiano enamel SEM image before and after bleaching

Fig.2
A pilot study was conducted to see the effect of the application 16% CP (Teeth Whitening Gel, White Dental Beauty) on sound enamel. Representative SEM images at 16000× magnification (a) sound enamel; (b) 16% CP (Teeth Whitening Gel, White Dental Beauty), application period similar to 2 weeks. SEM images showed no major changes to enamel topography after bleaching.

styleitaliano style italiano color assment before bleaching

Fig.3
A pre-operative picture is mandatory to select the proper shade and to assess the evolution of the bleaching treatment (the initial shade obtained in this case was A3.5 VITA classical in the cervical region and A3 VITA classical in the middle and incisal regions).
This picture was taken with the help of Smile Lite MDP device and a Note 9 smartphone in order to compare color deviations between the shade guide and the tooth. Six LEDs on each side of the lateral lights were turned ON and covered with the white diffusers, giving the twin flash effect. Two retractors and one black photographic background (Flexipalette, Smile Line, Switzerland) were used. A3.5 and A3 samples were placed near the natural tooth with edge-to-edge position.

style italiano styleitaliano smileline dental photography flexipalette
style italiano styleitaliano smileline dental photography flexipalette
styleitaliano style italiano polarized picture during shade matching

Fig.4
A polarized picture can be of great help in showing the difference in color compared to the shade guide, and to better frame the issue. Shade was obtained without reflection, and this could be possible by using the polarizing filter mounted on the central light of the Smile Lite MDP device (Smile Line, Switzerland). Only the central light must be ON in this kind of picture.

styleitaliano style italiano polarized dental shade match

Fig.5
Another polarized picture for the patient placed in occlusion before bleaching with cheek retractors and two shade guide samples.

styleitaliano style italiano white dental beauty whitening gels

Fig.6
For at-home treatment, the CP gel is available at 5%, 10%, and 16% concentrations, along with 6% HP (Teeth Whitening Gel, White Dental Beauty). It is important to note that White Dental Beauty gels all feature NOVON® patented technology for optimum performance and decreased sensitivity. The 5% CP Mild was designed specifically for patients with enhanced dental sensitivity. The 6% HP is a fast-acting formula with an application time of as little as 30 minutes per day. In addition, the 16% CP and 10%CP can be applied by day or night.

styleitaliano style italiano white dental beauty teeth whitening syringes

Fig.7
In this case, a 16% CP (White Dental Beauty, Optident, UK) was chosen to be applied 2-4 hours/ day for 2 weeks.

style italiano styleitaliano white dental beauty teeth whitening gels
style italiano styleitaliano white dental beauty teeth whitening gels
styleitaliano style italiano placing whitening gel into whitening tray

Fig.8
The patient was instructed how to insert the bleaching trays and to apply the 16% CP gel in the amount of a drop per tooth (the size of half rice grain). Syringes could be delivered to the patient for a period of one week.

styleitaliano style italiano picture after one week dental whitening

Fig.9
Final result after 7 days of bleaching: The color obtained was verified with the same shade guide, and the most suitable was A1 from VITA classical. The difference between the initial shade guide A3.5 and the A1 shade guide could be noticed very well, which can be considered a good result visually and clinically.

styleitaliano style italiano whitening progress check polarized picture

Fig.10
Details from a polarized picture comparing the final color obtained with the initial A3.5 shade VITA classical shade guide after 7 days of at-home bleaching.

styleitaliano style italiano polarized picture, after one week whitening

Fig.11
The final result, after 7 days of bleaching with a polarized picture, was satisfying for the patient. To counterbalance color rebound, as no increase in sensitivity occurred, another week of at home whitening was done to stabilize the result.

styleitaliano style italiano comparing before shade and actual dental color

Fig.12
Another polarized picture comparing the final color obtained with the initial A3.5 shade VITA classical shade guide.

styleitaliano style italiano before and after comparison of at home bleaching for two weeks

Fig.13
Final result after 14 days of bleaching. The color obtained was verified with the same shade guide, and the most suitable was B1 from VITA classical. The difference between the initial shade guide A3.5 and the B1 shade guide could be noticed very well, which can be considered a successful outcome visually and clinically.

styleitaliano style italiano dental shade assessment after two weeks whitening

Fig.14
Beneficial effect after 14 days of bleaching with 16% CP.

styleitaliano style italiano final polarized picture after dental bleaching

Fig.15
The final result, after 14 days of bleaching with a polarized picture, was pleasing for the patient.

styleitaliano style italiano before and after dental whitening

Fig.16
Details from a polarized picture comparing the final color obtained with the initial A3.5 shade VITA classical shade guide after 14 days of at-home bleaching. The patient was able to see the evolution of the treatment by seeing the pictures taken by the MDP device.

styleitaliano style italiano final result after dental at-home whitening treatment

Fig.17
The patient was satisfied and happy with the result. Some tips were given to the patient to preserve the bleaching effects for a long period of time.

styleitaliano style italiano stages of at home whitening

Fig.18
All stages of dental bleaching, before and after, polarized and non polarized, after one week and two weeks.

Conclusions

Home bleaching using CP at a low concentration (e.g., 16%) should be considered a good treatment alternative for in-office bleaching using HP at higher concentration (e.g., 35%). The home bleaching option using White Dental Beauty products was considered safe to treat discolored teeth and minimize tooth sensitivity. This could be explained by the presence of NOVON® technology active in all percentages of White Dental Beauty gels. NOVON® is a patented whitening compound that comprises HP, urea and sodium tripolyphosphate with an acidic pH value of 6.5. However, when NOVON® is diluted, the pH value rises to 8.5 (alkaline range).

The Smile Lite MDP device allows the use of the diffusers and polarizer filters in an easy way. As a consequence, the resulting pictures can be used to show the patient the initial situation and the evolution of the bleaching process with the artificial shade guide.
Since people perceive color differently, the use of a dental shade guide accurately determines the tooth color before and after treatment and can enhance the reliability of visual comparisons of tooth whitening outcomes.

Bibliography

1. Hardan LS. Protocols for Mobile Dental Photography with Auxiliary Lighting. Quintessence Publishing Co; 2020.
2. Manauta J, Salat A. Layers, An atlas of composite resin stratification. Quintessence Publishing Co; 2012.
3. Hardan LS, Moussa C. Mobile dental photography: a simple technique for documentation and communication. Quintessence Int. 2020;51(6):510-518.
4. Akal N, Over H, Olmez A, Bodur H. Effects of carbamide peroxide containing bleaching agents on the morphology and subsurface hardness of enamel. J Clin Pediatr Dent. 2001;25(4):293-6.
5. Orilisi G, Tosco V, Monterubbianesi R, et al. ATR-FTIR, EDS and SEM evaluations of enamel structure after treatment with hydrogen peroxide bleaching agents loaded with nano-hydroxyapatite particles. PeerJ. 2021;9:e10606.
6. Zanolla J, Marques A, da Costa DC, de Souza AS, Coutinho M. Influence of tooth bleaching on dental enamel microhardness: a systematic review and meta-analysis. Aust Dent J. 2017;62(3):276-282.
7. Ghaleb M, Orsini G, Putignano A, Dabbagh S, Haber G, Hardan L. The Effect of Different Bleaching Protocols, Used with and without Sodium Ascorbate, on Bond Strength between Composite and Enamel. Materials (Basel). 2020;13(12):2710.
8. Shamel M, Al-Ankily MM, Bakr MM. Influence of different types of whitening tooth pastes on the tooth color, enamel surface roughness and enamel morphology of human teeth. F1000Res. 2019;8:1764
9. Lima SNL, Ribeiro IS, Grisotto MA, Fernandes ES, Hass V, de Jesus Tavarez RR, Pinto SCS, Lima DM, Loguercio AD, Bandeca MC. Evaluation of several clinical parameters after bleaching with hydrogen peroxide at different concentrations: A randomized clinical trial. J Dent. 2018;68:91-97.
10. Farawati FAL, Hsu SM, O’Neill E, Neal D, Clark A, Esquivel-Upshaw J. Effect of carbamide peroxide bleaching on enamel characteristics and susceptibility to further discoloration. J Prosthet Dent. 2019;121(2):340-346.

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