CASE REPORT

THE IMPORTANCE OF ELAPSED TIME BETWEEN TOOTHBLEACHING AND REPLACEMENT OF COMPOSITE RESINRESTORATIONS: CASE REPORT.

INTRODUCTION

he aim of the contemporary restorative dentistry isto restore the anatomical features and functions of

the tooth, along with the esthetic concerns of everyindividual patient. Tooth whitening is considered the mostconservative treatment for discolored teeth and one of themost requested by those who look for esthetic enhancementof their smile.1

The action mechanism of bleaching agents is based ona complex oxidation reaction releasing oxygen free radicalsthat penetrate through the porosities of the enamel prismto the dentin.2, 3

Although treatment options for traumatic dental fracturesdepend on many factors including the extent of the trauma,the quality and timing of the initial intervention and thepresence or absence of dental fragments.4 Direct compositeresin restorations of fractured teeth have shown morelongevity than repositioned fragments.5 Bonded aestheticrestorations are emphasized by the advantages they offerlike tissue preservation, longevity and esthetic properties.4,6

When both procedures are considered simultaneously duecautions have to be taken into account. This case reports

the association of dental bleaching and replacement ofdirect composite resin restorations to improve esthetics ofupper central incisors.Clinical report

A 26-year-old girl presented with 12 years old,

aesthetically compromised Upper Central Incisors restoredwith composite resins for fracture treatment (figure 1).Patient was concerned about the discoloration of teeth andrestorations, and the loss of surface gloss on resinrestorations. Periapical radiograph revealed no periapicalpathosis and the pulp vitality test was positive for bothteeth. On the basis of clinical and radiographic finding adefinitive treatment plan was made.

The first stage of treatment consisted of two in-officebleaching sessions (1 week interval) with 3 applications,of 15 min each, of 35% hydrogen peroxide (Mix One,Villevie, Joinville, SC, Brazil) (figure 2). After 10 days ofbleaching treatment, the discolored restorations werechanged by new ones following the anatomic stratification

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An increased demand for esthetic treatment requires the dentists to keep abreast with the contemporary knowledgeof both, the advancements in dental materials and latest techniques to deal with them. This clinical case reportsthe association of tooth bleaching and replacement of direct resin composites on upper central incisors fracturedand restored during childhood.KEYWORDS: composite resin, dental bleaching, fractured incisors.How to cite this article: Iqbal F, Hilgemberg SP, Garcia EJ. Association of tooth bleaching and replacement ofcomposite resin restorations of fractured teeth: case report.J Pak Dent Assoc 2013;22(2):144-146.

TFigure 1. Preoperative view of the upper central incisors.

Fahad iqbal1

Sergio Paulo Hilgemberg2

Eugenio Jose Garcia3

BDSDDS, MSDDS, MS, PhD

1 Private practice, Khyber pakhtoonkhwa, Pakistan .2 Private practice, Ponta Grossa, PR, Brazil.3 PhD student, School of Dentistry, Department of

Department of Dental Materials, University of Sao Paulo, SP, Brazil.

Correspondence: Farhan Iqbal<doc.fahadiqbal@gmail.com> Mobile : 0314-5000303

Iqbal F, Hilgemberg SP, Garcia EJ Tooth bleaching and replacement of composite resint

to replicate the polychromatic characteristics of the naturaldentition. First, the lingual surfaces and incisal edges were

recorded with a putty silicone stent (figure 3). Enamelwas etched for 30 sec and the dentin for 15 sec with 35%phosphoric acid, rinsed for 60 sec and gently air-dried.Then, a two-step adhesive system (Single Bond, 3M ESPE,St. Paul, MN, USA) was applied following manufacturer’sinstructions. The initial layer (palatal enamel) of compositeresin (Clear, Four Seasons, Ivoclar Vivadent, AG,Liechtenstein) was applied using the silicon guidepreviously confectioned intraorally (figure 4). The nextincrements followed the schematic diagram to obtain abiomimetic restoration: resin (A1 Dentin) to reproducethe incisal halo and dentin lobes, Clear-resin for the spacesbetween dentin lobes and the final increments of enamel(B1 Enamel and Medium Value). Each increment waspolymerized with a curing unit for 40 sec, allowing the

placement of subsequent increments without deformingthe underlying composite layer.

Finishing and polishing were performed with disks,burs, strips and pastes according to the grit and rangedfrom coarse to extra fine in order to obtain the final gloss

and control of incisal contacts (figure 5).

DISCUSSION

As the popularity of aesthetic treatments has increased,improvements have been made to in bleaching and resincomposite products.7,8 The use of these two proceduresconserve the natural tooth structure while allowing theanatomy and color to be restored successfully.

Dental bleaching provided a higher and morehomogeneous value of the anterior segment and withinthe thirds of each tooth. No light sources were used toaccelerate the bleaching process since literature showedthe lack of efficacy of this kind of devices.9 The effect ofbleaching agents on properties of composite resins hasbeen the focus of an in vitro study.10 Although someauthor have showed that composite color changes canrange between 2 and 11 (E), as reported in this clinicalcase (figure 2), color discrepancies between teeth andcomposite restorations after bleaching treatment demanded

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Figure 2. In-office tooth bleaching

Figure 3. Confection of silicone matrix

Figure 4. First increment of enamel positioned on left centralincisor.

Figure 5. Postoperative.

the replacement of this restorations.Bonding of adhesively attached restorations to pre-bleacheddental hard tissue can be significantly reduced11-13 byleaching of peroxide by-products.14-16 Although severalalternatives have been proposed to avoid waiting; however,by now there is a consensus that the only clinical protocolis to delay placement of restorations for at least 1 – 3weeks.17,18 An elapsed time between bleaching and estheticrestorations is also necessary to allow teeth rehydrationand stabilization of the final color.

Several factors have been related to jeopardize thelongevity of class IV composite restorations.19,20 Thesevariables, if controlled, can increase the success andlongevity of the treatment.

CONCLUSION

Bonded restorations associated to bleaching treatmentare highly recommended for the treatment of the anteriorsegment. However, an elapsed time must be consideredto avoid premature failures of immediately bondedrestorations.

REFERENCES:

1. Kimyai S, Valizadeh H. The effect of hydrogel and solution of sodium ascorbate on bond strength in bleached enamel. Operative Dentistry. 2006; 31:496-499.

2. Cooper JS, Bokmeyer TJ, Bowles WH. Penetration ofthe pulp chamber by carbamide peroxide bleaching agents. Journal of Endodontics. 1992; 18:315-317.

3. McEvoy SA. Chemical agents for removing intrinsicstains from vital teeth. II. Current techniques and theirclinical application. Quintessence Int. 1989; 20:379-384.

4. Brambilla GP, Cavalle E. Fractured incisors: a judiciousrestorative approach--part 1. Int Dent J. 2007; 57:13-18.

5. Garcia-Ballesta C, Perez-Lajarin L, Cortes-Lillo O, Chiva-Garcia F. Clinical evaluation of bonding techniques in crown fractures. J Clin Pediatr Dent. 2001; 25:195-197.

6. Garoushi S, Vallittu PK, Lassila LV. Direct restorationof severely damaged incisors using short fiber-reinforcedcomposite resin. J Dent. 2007; 35:731-736.

7. Ferracane JL. Buonocore Lecture. Placing dental composites--a stressful experience. Oper Dent. 2008;33:247-257.

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9. Buchalla W, Attin T. External bleaching therapy withactivation by heat, light or laser--a systematic review.Dent Mater. 2007; 23:586-596.

10.Attin T, Hannig C, Wiegand A, Attin R. Effect of bleaching on restorative materials and restorations--asystematic review. Dent Mater. 2004; 20:852-861.

11.Basting RT, Rodrigues JA, Serra MC, Pimenta LA. Shear bond strength of enamel treated with seven carbamide peroxide bleaching agents. J Esthet RestorDent. 2004; 16:250-260.

12.Bishara SE, Oonsombat C, Soliman MM, Ajlouni R, Laffoon JF. The effect of tooth bleaching on the shearbond strength of orthodontic brackets. Am J Orthod Dentofac ia l Or thop. 2005; 128:755-760.

13.Titley KC, Torneck CD, Smith DC, Applebaum NB. Adhesion of a glass ionomer cement to bleached and unbleached bovine dentin. Endod Dent Traumatol. 1989; 5:132-138.

14.Montalvan E, Vaidyanathan TK, Shey Z, Janal MN, Caceda JH. The shear bond strength of acetone and ethanol-based bonding agents to bleached teeth. PediatrDent. 2006; 28:531-536.

15.Sasaki RT, Flório FM, Basting RT. Effect of 10% sodium ascorbate and 10% -tocopherol in different formulations on the shear bond strength of enamel anddentin submitted to a home-use bleaching treatment. Operative Dentistry. 2009; 34:746-752.

16.Torres CRG, Koga AF, Borges AB. The effects of anti-oxidant agents as neutralizers of bleaching agents on enamel bond strength. Brazilian Journal of Oral Science.2006; 5:971-976.

17.Barbosa CM, Sasaki RT, Florio FM, Basting RT. Influence of time on bond strength after bleaching with35% hydrogen peroxide. J Contemp Dent Prac. 2008;9:81-88.

18.Torneck CD, Titley KC, Smith DC, Adibfar A. The influence of time of hydrogen peroxide exposure on the adhesion of composite resin to bleached bovine enamel. J Endod. 1990; 16:123-128.

19.Macedo G, Raj V, Ritter AV. Longevity of anterior composite restorations. J Esthet Restor Dent. 2006; 18:310-311.

20.Spinas E. Longevity of composite restorations of traumatically injured teeth. Am J Dent. 2004; 17:407-411.

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Iqbal F, Hilgemberg SP, Garcia EJ Tooth bleaching and replacement of composite resint