Combining Enamel Microabrasion and Dental Bleaching: Recovering Smile Aesthetics

IBTRODUCTION
The presence of stains and superficial irregularities in dental enamel surfaces can be solved through the use of an enamel microabrasion technique; however, these intrinsic alterations should have a hard texture, can have any coloration, and affect the superficial layers of dental enamel.^1-6
Many factors can cause these superficial alterations, such as imperfect amelogenesis, imperfect enamel formation, or the removal of an orthodontic appliance in adolescent patients with poor dental hygiene during its use. For a long time, the clinical treatment consisted of its removal and restoration of the obtained cavities using composite resin.⁶
Nowadays, we can employ enamel microabrasion procedures using acid/abrasive products, which not only allow an economy of healthy dental tissues but also provide permanent and considerable aesthetic results.⁷ It has been observed that, after enamel microabrasive procedures, the teeth may acquire a yellowish coloration because of the thinness of the remaining enamel surface, revealing the dentinal tissue more. In these conditions, the correction of the color pattern of teeth may be obtained with products containing carbamide peroxide in custom trays or hydrogen peroxide in the office.^6,7 This article presents the protocols for an enamel microabrasion technique for the removal of stains present on the buccal enamel surface, followed by tooth bleaching with carbamide peroxide.

CASE REPORT
Diagnosis and Treatment Planning
A 19-year-old female presented with intrinsic white stains of a hard texture located on the buccal-enamel surface of all maxillary incisors, canines, and premolars. These alterations were observed after the removal of her orthodontic brackets (Figure 1). For their removal, an enamel microabrasion technique was proposed using an enamel microabrasive product containing a mild concentration of hydrochloric acid (6%) and a fine-grit silicon carbide abrasive in a water-soluble gel (Opalustre [Ultradent Products]).
Clinical Protocol
The enamel microabrasion procedures were performed after enamel macroabrasion of the affected enamel surfaces, using a fine-grained diamond bur (3195 FF [KG Sorensen]) under a water and air spray to keep the surfaces cool (Figure 2). This was followed by the color pattern correction as well as the uniformization of the dental enamel surface with the application of an enamel microabrasive (Opalustre), applied under rubber dam isolation (Figure 3). (Eye protection was worn by the clinical team and by the patient during these procedures.)

Figure 1. A 19-year-old female with intrinsic white stains of hard texture located on the buccal-enamel surface of all maxillary incisors, canines, and premolars.	Figure 2. Application of fine-tapered diamond bur (No. 3195 FF) on the vestibular surfaces of the superior all maxillary incisors, canines, and remolars.
Figure 3. Application of the microabrasion material (Opalustre [Ultradent Products]) on the enamel surface after total isolation with a rubber dam.	Figure 4. Application of Opalustre for one minute in each application of the compound.
Figure 5. Removal of the microabrasion paste with water and air spray.	Figure 6. Polishing with fluoride paste, following the completion of enamel microabrasion.

Figure 7. Application of 2% neutral sodium fluoride gel.

Figure 10. During dental bleaching with 10% carbamide peroxide gel (Opalescence [Ultradent Products]).

The enamel microabrasive material was applied with a rubber cup (provided by the manufacturer) mounted on a 10:1 gear reduction angle. A small quantity of the product was applied firmly in each region affected by stains, 3 times for one minute each; and periodic washing with water was done between each application (Figures 4 and 5). After the last application, the teeth were copiously washed and dried, receiving shortly thereafter a polish with fluoridated paste, Herjos F (Vigodent S/A Indústria e Comércio) (Figure 6). Next, a 2% neutral sodium fluoride gel (Farmácia Quality Pharma [Araçatuba]) was applied to the microabrasioned dental enamel for 4 minutes (Figure 7). After removal of the rubber dam, the patient was advised not to ingest solids or liquids for at least 30 minutes (Figures 8 and 9).
One month after the enamel microabrasion procedures, we opted to perform dental bleaching employing 10% carbamide peroxide gel (Opalescence [Ultradent Products]). Maxillary and mandibular alginate impressions were taken, and the custom trays were fabricated in the usual manner. After being cut, they were analyzed with respect proper fit to the teeth and gingival tissues. The patient was instructed to place a small drop of the bleaching gel in the deepest portion of the custom tray in the region correspondent to each tooth to be bleached. The bleaching technique was performed for 4 hours daily for 3 weeks (Figure 10). To obtain the desired shade, it was necessary to use the bleaching method for 4 weeks (Figures 11 to 12).

DISCUSSION
The reports of Croll and Cavanaugh in 19862 and Sundfeld et al in 19901 proposed the application of an enamel microabrasion technique for the removal of superficial enamel stains, using 18% hydrochloric acid mixed with fine-grained pumice stone, which was applied to the enamel surface with a wooden stick; observing that, beyond the considerable aesthetic and permanent results obtained, there was a verified insignificant loss of enamel.¹
However, the caustic and toxic effect of 18% hydrochloric acid demanded the constant attention of an operator and assistant during its application. In searching for an ideal acid/abrasive product that presented easier application and higher safety for the oral tissue, the operator, and the assistant, some enamel microabrasive products were introduced to the dental market made from a mild concentration of hydrochloric acid. Combined with a fine-grit abrasive formula, this provided for safe application in the mouth. Among these products was the Opalustre microabrasive product.^3,6,8
Making use of these microabrasive products, Sundfeld et al in 1995⁹ and Croll and Bullock in 1994¹⁰ tried to reduce the time needed for the enamel microabrasion technique for the removal of stains as well as the amount of microabrasive product to be used, suggesting that the procedure begin with the macroreduction of the affected enamel using a fine-tapered diamond bur (3195 FF) to lightly abrade the spotted area; with this procedure, 2 or 3 applications of enamel microabrasive products are required to achieve the desired level of aesthetics.^6,11,12 It has been observed also that the teeth of patients subjected to enamel microabrasion have a smooth, prism-free layer of enamel and a lustrous surface that increases over time.6,10 This effect, called the “abrasion effect,”¹² may be due to the compaction and deposition of calcium and phosphate breakdown of products that result from the simultaneous erosive and abrasive action of the microabrasion.^10,12
It is interesting to consider that with deeper stains, which may not be removed by the enamel microabrasion technique, the tooth should be restored with composite resin in the same session.^3,6
Even with the loss of dental enamel considered irrelevant,1,6 the teeth may acquire a darker and yellowish color because of the thinness of the remaining enamel surface, revealing the dentinal tissue. In these cases, the correction of the color pattern may be obtained with the use of bleaching products based on carbamide peroxide or hydrogen peroxide at higher concentrations, or even with a combination of these techniques. However, the application of the bleaching gel must be done on healthy teeth surfaces and mostly without dentinary exposition (exposed dentin tubules) on the cervical and/or incisal area (that can lead to hypersensitivity). In addition, all dental bleaching treatments must be done under professional supervision.^6,7

CONCLUSION
This case report presents a clinical protocol for enamel stain removal followed by dental bleaching using carbamide peroxide. In the clinical case presented here, the enamel microabrasion technique combined with dental bleaching using carbamide peroxide is a highly satisfactory and safe procedure providing satisfactory aesthetic results.
It can be concluded that the removal of enamel stains through application of the microabrasion technique, combined with the use of dental bleaching using 10% carbamide peroxide, provided the aesthetic recovery of our patient’s smile.

References

1. Sundfeld RH, Komatsu J, Russo M, et al. Removal of stains on dental enamel: a clinical and microscopic study. Rev Bras Odontol. 1990;47:29-34.
2. Croll TP, Cavanaugh RR. Enamel color modification by controlled hydrochloric acid-pumice abrasion. I. Technique and examples. Quintessence Int. 1986;17:81-87.
3. Croll TP. Enamel Microabrasion. Chicago, IL: Quintessence Publishing; 1991.
4. Sundfeld RH, Komatsu J, Mestrener SR, et al. Stains and superficial irregularities on dental enamel. Ambito Odontol. 1991;1:63-66.
5. Segura A, Donly KJ, Wefel JS. The effects of microabrasion on demineralization inhibition of enamel surfaces. Quintessence Int. 1997;28:463-466.
6. Sundfeld RH, Croll TP, Briso AL, et al. Considerations about enamel microabrasion after 18 years. Am J Dent. 2007;20:67-72.
7. Sundfeld RH, Rahal V, Croll TP, et al. Enamel microabrasion followed by dental bleaching for patients after orthodontic treatment—case reports. J Esthet Restor Dent. 2007;19:71-78.
8. Croll TP. Enamel microabrasion: observations after 10 years. J Am Dent Assoc. 1997(suppl);128:45S-50S.
9. Sundfeld RH, Croll TP, Mauro SJ, et al. New clinical considerations about dental enamel microabrasion. Procedures effects and analysis time lapse. Efeitos da técnica e tempo de análise. Rev Bras Odontol. 1995;52:30-36.
10. Croll TP, Bullock GA. Enamel microabrasion for removal of smooth surface decalcification lesions. J Clin Orthod. 1994;28:365-370.
11. Sundfeld RH, Croll TP, Killian CM. Smile recovery VII – proof of efficacy and versatility of dental enamel microabrasion procedures. J Bras Dent Estet. 2002;1:77-86.
12. Donly KJ, O’Neill M, Croll TP. Enamel microabrasion: a microscopic evaluation of the “abrosion effect”. Quintessence Int. 1992;23:175-179.

Dr. Machado is in restorative dentistry, Araçatuba Dental School, São Paulo State University, Araçatuba, Brazil. He can be reached at lucassilveira1@yahoo.com.br.

Dr. Neto is in dental materials, Piracicaba Dental School, Campinas University, Piracicaba, Brazil. He can be reached at daniel_bozy@hotmail.com.

Mr. Gustavo Barbosa de Oliveira is an undergraduate student, restorative dentistry, Araçatuba Dental School, São Paulo State University, Araçatuba, Brazil. He can be reached at gustavob75@gmail.com.

Ms. Carvalho is an undergraduate student, restorative dentistry, Araçatuba Dental School, São Paulo State University, Araçatuba, Brazil. She can be reached at thays_rodrigues@hotmail.com.

Dr. Fernanda Garcia de Oliveira is in restorative dentistry, Araçatuba Dental School, São Paulo State University, Araçatuba, Brazil. She can be reached at fergaroli@hotmail.com.

Dr. Sundfeld is a professor of restorative dentistry, Araçatuba Dental School, São Paulo State University, Araçatuba, Brazil. He can be reached via e-mail at sundfeld@foa.unesp.br.

Disclosure: The authors report no disclosures.