Esthetic Dentistry

Enamel niicroabrasion followed by dental bleaching: case reportsTheodore P. Croll*

Certain enamel coloration defects can best be eliminated by a combination of treatmentmethods. This report describes the treatment of two patients whose enamel discolora-tion was corrected with a combination of enamel microabrasion and patient-administereddental bleaching with a carbamide peroxide gel solution.{Quintessence Int 1992:23:317-321.)

Introduction

Enamel tnicroabrasion has been shown to correct cer-tain enamel dysmitieralization and décalcification col-oration defects by removal of the superficial layer ofthe enamel surface.'^ In some cases, after enamelmicroabrasion is completed, the underlying naturaltooth color may appear too yellow or dark for the pa-tient's and dentist's liking,

Archambault has treated patients first with enamelmicroabrasion for removal of surface defects and thenwilh topical application of bleaching solution adminis-tered within custom-formed, soft vinyl mouth trays(Archambault G: Personal communication, 1990). The"home" tooth-bleaching technique has become popularover the past few years."""̂

This report describes the two-step tooth color im-provement achieved in two patients who benefited firstfrom enamel microabrasion and addifionally fromtooth bleaching.

* Private Practice, Pediatric Dentistry, Doylestown, Pennsylvania;Clinical Assoeiate Professor, Department of Pediatric Dentistry,University of Pennsylvania, School of Dentai Medicine; AdjunetProfessor, Department of Pediatric Dentistry, University ofTesas, Health Science Center at Houston (Dental Branch),

Address all correspondence to Dr T, P, Croll, Georgetown Com-mons, Suite 2, 708 Shady Retreat Road, Doylestown, Pennsyl-vania 18901.

Case 1

A teenaged boy presented with a chief complaint of"spotted teeth" (Fig 1). Some of the discoloration wasrelated to plaque accumulation and extrinsic enamelstain from inadequate oral hygiene practices. The pa-tient also demonstrated generalized while enamel dys-mineralization,'^"* which appeared as white streaksand blotches especially noticeable on the anteriorteeth. Although no distinct etiology of the white dis-coloration could be determined, excess ingestion offluoridated dentrifice in the childhood years could notbe ruled out.

After home-care instructions and dental cleaning,the patient was scheduled for a 60-minute appoint-ment. At that time, the maxillary anterior teeth wereanesthetized and isolated with the rubber dam, andthe complete crown of each tooth was exposed withdental tape ligation. Enamel microabrasiun usingPRÉMA compound (Premier Dental Products) wasperformed in the standard manner'""* {Fig 2).

One week later, the same treatment was performedfor the mandibular incisors and canine teeth. Theresults of enamel microabrasion are shown in Fig 3,Before the patient was dismissed at the second enamelmicroabrasion appointtnent, maxillary and mandibularalginate impressions were reeorded and dental stonecasts poured for fabrication of custom-fitted, soft vinylmouth trays.

Because the underlying natural color of the patient'senamel was too yellow in contrast to the residual whiteenamel dysmineralization, it was decided to have thepatient undergo a 3-week course of home bleachingusing a bleaching gel applied in custom-formed, soft

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Fig 1 This teenager has generalized while enamel dys-mineraiization'-^-'' that gives his teeth a white-yeliow, blotchyappearance.

Fig 2 After locai anesthetic injections, rubber dam appii-cation, and compiete coronai exposure with dental tapeligation, enamel microabrasion is performed for labial sur-faces of all anterior teeth.

Fig 3 After conservative enamel microabrasion, toothappearance is improved, but the intrinsic yeiiow coior isapparent.

Fig 4 Soft vinyl, custom-fitted trays for both arches havebeen made. The patient is instructed in nocturnal use ofcarbamide peroxide bieaching gei for a period of 3 weeks.

Fig 5 The maxillary and mandibular trays, filled withbleaching solution, are shown in piace.

Fig 6 The bleaching trays are else used for iG-minute ap-plications of neutral sodium fluoride gel once a day for 3weeks after the bleaching procedure has ceased.

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Fig 7 Three weeks after completion of enamel microabra-sion, bieaohing, and topical application of neutral sodiumfluoride gel, tooth color is improved. This 6-month post-treatment view was taken before dental prophylaxis (com-pare with Figs 1 and 3),

vinyl trays. The patient was instructed on the use ofthe maxillary and mandibular trays and provided witha suppiy of Opalescence carbamide peroxide gel (Ultra-dent Products, Inc) (Figs 4 and 5), The patient wastold to place the trays at bedtime and wear them untilhe arose in the morning. After 3 weeks, tooth colora-tion was improved. Although some patients have re-ported tooth sensitivity or developed gingival iirrita-tion during custom-tray home bleaching, this patientexperienced neither.

Because it has been suggested that dental bleachingsolution can decrease the wear resistance of enamei,^the patient was shown how to use the bleaehing traysas home flnoride-application trays for 10 minutes aday, with neutral sodium fluoride gel. for an additional3 weeks after treatment (Fig 6). It was thought thatthe topical fluoride application could possibly improvethe superficial enamel structure by fluoride ion sub-stitution in the enamei crystals of the tooth surface,thus rendering the superficial enamel layer more wearresistant. The patient was advised that additionalhome bleaching couid be performed as required if theenamel regained its original yellow appearance. Sixmonths after cessation of the bleaching procedure, thetreated teeth were light colored and displayed a smoothtexture and shine characteristic of mieroabradedenamel after the "abrosion effect"^ (Fig 7),

Case 2

A teenaged girl demonstrated cervical enamel décal-cification lesions associated with inadequate dentalplaque removal dnring her past orthodontic therapy(Fig 8), She also had generalized white enamel dys-mineralization, which gave the teeth a yellow andwhite streaked appearance. In addition, the maxillaryright laterai incisor had a carious lesion involving themesiolabial line angle. It was decided to performenamei microabrasion, which would be followed bypatient-administered tooth bleacbing, as indicated.Once bieaching was completed, the carious lesion ofthe lateral incisor would be restored with a labial-ac-cess, dentin- and enamel-bonded, pholopolymerizedcomposite resin restoration,'" The restoration wasdelayed so that composite resin shade selection couldbe as accurate as possible.

Before the rubber dam was placed, the patient wasanesthetized and braided retraction cord placed tofully expose the decalcified areas (Fig 9), Localanesthetic is rarely required for enamel microabrasion,but is useful for cases in which the enamel surface dis-coloration extends to or beyond the gingival margin.Enamel microabrasion was performed for all canineand incisor teeth in two 1-honr appointments (Fig 10),Some residual cervical white discoloration of the man-dibular teeth was not removed with enamel microabra-sion because the enamel layer of mandibular anteriorteetb is relatively thin, and in this patient those re-gions were not cosmctically prominent. What remained,however, was hard tooth structure that could not bescraped away with a sharp hand instrument, A supplyof bleaching gei and custom-formed trays were givento the patient with instructions for 3 weeks of noctur-nal application of the gel. Twenty-one days later, toothcolor had appreciably improved (Fig 11), At that time,the lateral incisor was restored with composite resin asdescribed by Croll and Donly,"'This patient reportedthat her anterior teeth were somewhat sensitive duringthe 3-week bleaching period, but she was able to toler-ate the discomfort with occasional use of acetomin-ophen. Six months later, the appearance of the teethshowed noticeable improvement (Fig 12),

Discussion

These cases confirm previous observations"'^ (Ar-chambault G: Personal communication, 1990) thathome bleaching can lighten and improve the appearanceof teeth that appear too dark or yellow after eomple-

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Fig 8 After orttiodontic treatment, this teenaged girl haswhite cervical décalcification iesions, and a mesial cariouslesion of the maxillary right lateral incisor. Generalizedwhite dysmineralization also gives the teeth a streaked ap-pearance.

Fig 9 Locai anesthesia, gingivai retraction, and carefulrubber dam application are used during enamei microabra-sion. All canine and incisor teeth were microabraded in twovisits.

Fig 10 After conservative enamel microreduction usingstandard enamel microabrasion methods,^"" the teeth showsome improvement.

Fig 11 After 3 weeks of tiome bleaching, more color im-provement is apparent. The mesial carious iesion of theright lateral incisor lias not yet been restored.

Fig 12 Ttiis 5-month posttreatment view confirms toothcolor improvement that has resulted from enamel mioro-abrasion, home-applied carbamide peroxide bieaching, andimperceptibie, bonded composite resin restoration of thelaterai incisor.

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tion of enatnci microahrasioti. In more complex casesof tooth tliscoloration, in which enamel stain pene-trates the tooth stritetLire deeply, or the tooth tliscol-oration results from deep intrinsic dentinai discolora-tion, composite resin or bonded porcelain veneer re-storations are the best treatment options.

It is not known why a patient may have tooth sen-sitivity or gingival irritation from carbamide peroxidecustom-tray bleaching, but such problems are knownto subside after cessation of treatment.^ Becauseenamel microabrasion results in .slight reduction of theenamel surface layer, it is possible that combined treat-ment may predispose tbe patient to pulpal sensitivity.The reasons for gingival ehanges and dental discom-fort in some bleaehing patients sbotild be investigated.

Beeause enamel microabrasion improves tooth ap-pearance by microreduction of the enamel surface, itis logical to perform microabrasion before bleaching.Treatment order was reversed in another teenaged pa-tient, and superficial enamel discoloration remainedafter initial bleaching. In that patient, an additional3-week bleaching regimen was required after enamelmicroabrasion to obtain successful results.

The abrosion effeet,'' which results in a smooth,prism-free layer of enamel and a Instrons surfacesheen that increases over time, apparently is not influ-enced by bleaching. In these two patients, enamel sur-faces acquired a glasslike "enamel glaze" months aftertreatment, just like teeth of patients who were treatedwith enamel microabrasion alone.

Acknowledgment

The author aeknowledges iinancial interest in PREMA Com-pound by virtue of a licensing agreement with Premier DentalProduets.

References

1. Croll TP: Enamel microabrasion: the technique. Quintessencelm 1989;20:395^00.

2. Croll TP: Enamel mieroabrasion for removal of superficialdiscoloration. J Esthet Dent 19R9;1:I4-2O.

3. Croll TP: Enamel microabrasion for removai of superiicialdysmineralization and décalcification defects. / Am DenlAssoc 1990;120:411-415.

4. Croll TP: Enamel Microatirasion. Chicago, Quinlesscnee PuhlCo, 1991.

5. Haywood VB, Heymann HO: Nightguard vital bleaching.Quintessence Int 1989;20:173-176.

6. Adept Institute: Lightening natural teeth. Adept Repon 1991;2(1):9-15.

7. Haywood VB: Overview and status of mouthguard bieaching.3 Esther Denl t99I;3:t57-161.

8. Kalili T, Caputo AA, Mito R, et al: ln vitro toothbrush abra-sion and bond strength of bleached enamel. Practical Period-ont Aeslhel Dent 1991:3:22-24.

9. Donly KJ, O'Neili M, Croil TP: Enamel microabrasion: amicroscopic evaluation of the "abrosion effecl." QuintessenceInt 1992:23:175-179.

to. Croli TP, Donly KJ: Imperceptible bonded eomposite resinClass HI restoration using labial access. Quinlessence Int 1990;21:79.5-799,

11. Clinical Research Associates: Enamel microabrasion. CtinRes Assoc Newsletter 199O;I4(I1):].

12. Cvitko E, Swift EJ. Denehy GE: Improved estheties with acombined bleaching technique: a ease report. Qumtes.ience Int1992;23:91-93. D

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