,,-

~Operative Dentistry, 2005, 30-2, 156-163

Efficacy, Side-effects andPatients' Acceptance of

Different Bleaching Techniques(OTC, in-office, at-home)

" ,- """' "'\

TM AuschilV. ~ H~ll~g · S SchmidaleA Sculean · NBArweiler

Clinical Relevance

The outcome of this clinical study suggests that the three evaluated bleaching tech-niques resulted in the desired whitening of teeth within the recommended applicationtime periods. Each method was also well accepted by the patients. The side effects thatoccurred were reversible and none of the products tested resulted in detectable changesin the enamel surface.

SUMMARY

This clinical study compared the efficacy of threedifferent bleaching techniques with respect tothe bleaching times required in order to achievesix grades of whitening in human teeth. Any sideeffects that were noted and the patients' accept-ance of the method were recorded by a visualanalog scale ranging from 0 to 10. Moreover,epoxy casts from the study teeth were analyzedby scanning electron microscopy in order to

*Thorsten Mathias Auschill, DDS, Dr med dent, PhD, associateprofessor, Department of Operative Dentistry andPeriodontology, Albert-Ludwigs-University, Freiburg, Germany

Elmar Hellwig, DDS, Dr med dent, PhD, professor and head,Department of Operative Dentistry and Periodontology, Albert-Ludwigs-University, Freiburg, Germany

Sonja Schmidale, DDS, Albert-Ludwigs-University, Freiburg,Germany

Anton Sculean, DDS, Dr med dent, MS, PhD, professor andhead, Department of Periodontology, University MedicalCenter, Nijmegen, Netherlands

Nicole Birgit Arweiler, DDS, Dr med dent, PhD, associate pro-fessor, Department of Operative Dentistry and Periodontology,Albert-Ludwigs-University, Freiburg, Germany

*Reprint request: Hugstetter StraJ3e 55, 79106 Freiburg i Br,Germany; e-mail: auschill@zmk2.uk1.uni-freiburg.de

I,

detect any potential changes in the enamel sur-face due to treatments.

Thirty-nine volunteers participated in thestudy and were allocated randomly to one ofthree different bleaching treatments: Group A(n=13) used Whitestrips (over-the-counter tech-nique; one cycle=30 minutes), Group B (n=13)used Opalescence PF 10% (at-home bleachingtechnique; one cycle=8 hours) and Group C ~

(n=13) used Opalescence Xtra Boost (in-office ,,'

bleaching technique; one cycle=15 minutes) until ja defined whitening of six tabs compared to the 'baseline were reached (assessed by the VITA

"

shade guide). :All three methods achieved six grades of

whitening. The mean treatment time required to " I

reach the defined level of whitening was 31.85 :!:

j~

6.63 cycle~ in Group A, 7..15 :!:1.86 cycles in Group,',B and 3.1.:>:!:0.55 cycles m Group C. All products, '

differed significantly from each other in terms ofttreatment ,cycles and required treatment time !..(p<0.00l by ANOVA and Mann-Whitney-U-test).Using the VA scale, side effects noted within thethree groups were minimal. Tooth hypersensi-tivity ranged from 2.62 (Whitestrips) to 3.38(Opalescence PF), and gingival irritation ranged

.,,-,,,~~~,=,,,,,, < 'i .~';t.'~~~.-.~ ~~ ,..: ~ = '~...........-.-.. - ~ ..-

Auschill& Others: Clinical Comparison of Different Bleaching Techniques 157

have shown that higher concen,t.r8h.

on

.

mate,~als may )bleach teeth faster (Leonard (~h('r::', .19~18)1hey usu-ally work so rapidly that visible.:results caa be observed

\. after only a single visit.;3aell of tne descrlb"1!' . hniques h€"~-;;jj;;i?(.J~o.ill2-

ages and~v~ages '., r ~ih~2@Q~0t

~~~J?ali~S~~t}3!. AlPm.::crn..c1i~-:sme:eMeGjj;IStherm sensitlVItyof mdmdu . ,~blS may occurTooth bleaching has been described in the literature as

(9fiunng thebleaching proced.urean~~ua~IY stops when

early as 1889. Many.of these early attempts were ~ot S treatme~uspended. ~~b1~\:JS~very successful (Kirk, 1889). The most effect~ve ~'Ieactiiiig agents-J:ra~'R(.)-,heI?,:P:Jt~~~~~ae-J.R"mc;"hods involve the use of hydrogen peroxIde office~~~sP..Q£.~ M,~ n~~ nqt-g the.a.t..

(lwood, 1992). ~his bleachin? a?en~ e~able~ .the ~6TIi~llOOmg_-e~1hIa.i~q. '''';~g'']~i¥.jduaUytreatment to be effiCIent at remoVIng mtnnslC stammg, ~em--gned guaT<il~ g~~ Lao mlldmal \:ollL;;t(!tand most of the current vital bleaching materials con- with""§'0ft~u rJ ~~8~ ~e...J dLlJt11e::'ihave evar-tain hydrogen peroxide in some form, either as car- uatea~verse events as carcinogenicity (Dadounbamide peroxide or hydrogen peroxide per se & Bartlett, 2003) and effects on restorative materialsiFasanaro; 1992), Carbamide peroxide solutions are (Langsten & others, 2002; Turker & Biskin, 2003). Inunstable and dissociate into their constituent parts on vitro scanning electron microscopic evaluat~ons of thecontact with tissue or saliva (Haywood, 1992; Haywood surface texture of dentin (de Freitas & others, 2002)

& Heymann, 1989).(~arbaI?i~ J?eroxide. solu~ion and enamel treated with different bleaching agents({:-JZ03) breaks down mto hydrogen peroXIde r.H20z) showed little to no changes (Haywood, Houck &a -:- urea (Ca[NHz]z), after which the urea degrades Heymann, 1991; Leonard & others, 2001a; Auschill &into ammoma-1}.j!131 ana caroonaioxide (COz).The others, 2002).active agent (Hz02Fnas to be in contact WIth tneouter t e ereiit- tech;;iqu~a;'aiTaTiie -an,

-

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.d f t

. .d t d 1 / ecause O.l . , -

ename sUnace or ~peno 0 lme m?r er 0 eve op/, heir v 'n -':'croxi.de £QI)~Ge.tr:itty..rl§;.}['di~v~:iJii;' cAp0-

Its bleaching potentlal. Hy~ogen peroXIde breaks dovJn~:ure ti~' a~~-necessa in ~er to acl.1i~ve~he ~~mmto oxygen and water, which then penetrate the tooth~ I.

f hi%.

.Th' a;' rut ri~ on

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n.

.. /' .

~ve 0 w ~eIllU& .1 OWS I I v ..

and hberate the pIgment molecules. . the bleaching ,~-fQr-eaGh.i'afrient,.~.bich..~~7The most common methods used to remove dlscol- nlque.is e b~ch techniqJle..dQW3..the..na~nt.p..r.e;l

?' ..n from teeth consist oftw? clliricaland a non-cIin- ~!'I.",~Bt;.

. :cause The . Ooserv~iOns r~gardi~~'jIc.cc~que. At-home blea~hing IS a ~ethod wh~re @ectivenessandadverseeffects are stil~ controverslal~the patlent fills a custom-desIgned tray WIth bleaching nd. .Qn1~a few studie ed out un9fr

mate;:ial (10% to 20% c~rbamide ?eroxide resulting in iN mor.al..conditions-tbeonard 8z;-otli'"€rs,~200i-b';'~ek~nis: .

3.35-1% hydro.gen ~ero::ade) tha~ IS then worn for sev- ~othe):S';!2.

003), there.

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.

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.

sa'ne.ed~ormrrnfl

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o.

na..

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. =r8sprch

eral hours. Smce ItS mtroductlon by Haywood and o~"Ml:J~r15r:<:~Jy-1IVa!mQ1rbi~Gl::I'ti1g ~h-Heymann (1989), the original technique has undergone ~s. _ ___ _--some modifications. For example, there have been Th th

. f thi t d as to evaluate the effi-h . .I d

.d th f us, e aIm 0 s s u y w

c anges. m tray .mate~a ,tray eSlgn ~n e use 0 cac of the three bleaching techniques in vivo, possiblere"prVOlr and mgredlent concentratlOn (Leonard, . y h. ..

d,'

1 . 'ts]. '1' & H d 1998' Matis & others 2002). This s~de effect~ such as toot sensItiVIty an gmglva Im a-

. . a aywoo, '.' tlons, patlents' acceptance and any effects on enamelt:cumq.ue h~s become an efficIent, safe method for surface texture studied by scanning electronhghtemng discolored teeth. Over-the-counter (OTC) . (SEM)bleaching products (5.3% to 5.6% hydrogen peroxide) ffilcroscopy . .are sold as cosmetics and are freely available through METHODSAND MATERIALSstores, pharmacies and the Internet. They can be sold,for example, as either strip or varnish systems and maycause patients problems, because a dentist does notmonitor the bleaching procedure. The efficacy andstr 'Iral side effects of this system have not been fullyst: .1 (White & others, 2003). In-office bleaching isUSb~!lfor removing stains by using a high concentra-~on Qfhydrogen peroxide (3~38~. The dentist isIn completeconti-ol of the process throughout the treat-

m~nt. This provides the advantage of being able to;:&;\mlnate the discoloring process at any time. Stu~t1

between 0.23 (Opalescence Xtra Boost) and 0.85(\',T'hitestrips). The most accepted method was thea ome bleaching technique. None of the teethst",died showed detectable enamel surfacechanges in the subsequent SEM analysis using200x and 2000x magnification.

INTRODUCTION

This randomized, examiner blind clinical study used aparallel group design. It assessed intrinsic stainremoval and the occurrence of intraoral adverse effectsafter bleaching with three different bleaching tech-niques in vivo. In addition, their effect on enamel sur-face morphology was investigated by SEM.

Thirty-nine 1mT.!t'<tri~""JI>je(,.1:,;...,j'LqIl~~ere

~:~r: t111'S:Stl:ldy~.sl!1bje~ts""WiiJ~oorgeneral or. . eai~~rthodontL~IlP_1iaIJ.cS!s or known

hypersensitlvity were not :{}ermi'f'tedto.~i01'pate. An-

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158

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Operative Dentistry.~ 1";

(I \:. '1.V

The Vita'Value-oriented Shade Guide with 16 Shades Ranked From the Lightest Color onthe Left to the Darkest Color on the Right

82 02 M. C1 C2 04 A3 03 83 A3.5 84 C3 A4 C4

3 4 5 6 7 8 9 10 11 12 13 14 15 16

Table 1:

81

1

A1

2

For Group B, a-:m'9.%iI..jar'&{ ~J~ L I:~.d~. '~m'f)res-

;tw. ~~en=from-Ii~_~anMJ>~~fe18fB.@.

I

ddlL!VH VL d.",wl'IiL-eT1- I;mg Lray. f\ .i-mm tmccalre~ervOI1 f1 om L.fi't!

ngtit to t.he tett upper

~~-;J!~ cl>..-O.uI '.

~;,., TT]t.r..A./?l8It)

~*:

~oJu.\.o~u, 1H\.o, OvuLlr I;~,.rAP, 1:1SA). An I

etf'¥~Mc..e - V /Sof... 'a'S '~' ., """""~ ,""hone 11,e _aD "

we~::.k.l::~= dH::h lLCiY Mh:~h tke aleachingso'kit:iT;n~paieseeR~IU~/o carbanud~ peroxtde,Ul~'P.ntkf~~~".np.r niE!ht..

In Group C, ~e~@..{j@ iiflV<L4'1~~:latedll&i£..,.g~~(:nweR.t,;i~L .Jarn~p.x;n::!~_CQJ.t~,_l1i:m!erm.~'1:J'1"17'J~.,.Wit~~cr<W-..Q..~rLO'P miyinp" "--0 ~_ - :.;~~~~~ ~

procesS;-i;~.~~g&nt (n~~enGe:..X.tr.a..Boost, Z

~.~

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~er.(i)~d ~. .tra-dent1"WaS""dctiv'1ifetland a ,.

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. at;... . ...uti!.' ~'vU.:)l".U :1

. a~~l&;.l'elsa.~'Pl'!!Dment). r'~

Tts; -produd ~~ ~:t!!I;f~.P-IilP.r.~~.lct~h IS '.:

I ;emicall~ed"Wh~'~~ed .,lI g6.1i,.aetlvation. I wt{ f L'-<.-.k' IWithin each gr9u~th8.-1,Writeness:~t.lli4r_teeth :?"

~~ubje~pecte~ onrs-aft.e:r;.-J;1;te':I- ~eachin:~'S'iOLt,and the indivi ~5Ieachingsteps41

-:Wert:repe~until the expectedresult was reached; in ~ "."the case ofthis study, six tabs lighJ;er than the baseline .i

~value:-The exaininer Scored the shade of each test tooth ~

!by selecting the closest matching shade tab on the'\ l guide. If the examiners disagreed during the session, I

differences were discussed and an agreement reached. ~

Intraoral color slides were taken in order to record the Itooth shade for documentation of the baseline shade.'

and to compare whether a change in shade occurred,kShade determinations were always performed undertthe same conditions (for example, no lipstick, samelight source).

/ ]f2,r S~FEW..t~~nwnJ.t.w.iJ1g.QE:giJ1gi.>:W1irrij~~ ta9~-an --toot~~_a~.~ ere.

I a Ked to recO'fa-th: Gu.r-s-0~dail i

~\~ ~Vi~s.~0n':~~:ili~;~~~k:~~::1~~ treat~t'0"m:or~i~al response tlt1ie above mentioned side effects and their overimpression of the treatment (patients' acceptance(Zekonis & others, 2003). Table 2 shows abnormalitie

inclusion criterium was the presence of the right unre-stored upper canine, which was initially of grade A3 ordarker according to the VITA shade guide (VITAPfu~classical, \tlTA Zahnfabrik, Bad Siickingen, Germany).

The degree~: ~~~~s.e.v,ah:late.dJ>Y...£sing colorslide photo~-subjeetswga>,le-tf.18iJ;..~.tfen gJn-

s~t"'a'nd"'Completed a~calrnSto~~/'. ~subjects receiveQa_prm:essio~aI tootPlc~n'1lif

, ~rl1eostart..~~': .. d..W06lO€"ti~1i"tHlbo

/-::;? Th.e~'tteeth .t~~ y h the allocated tOothbrushL; J (elmexinter X, GABA nternational AG, Basel, CH)4-and two toothpastes (aronal/elmex, GABA

. International AG, Basel. ;t~~J~II!JIIt;~~e\ ~leani'I1~d""~~- u. .'!t'JVvU'\.o ~_ .~~.'o--

:t:~aihetl; "qualified-examinei's, wlio we!e'bHnd~t:.g.. a ment assignment and period. measured~Ibaselin

. e. tooth~~~~trarl~e"iYXr~A1~.a"kSl~_ ...;.~~bRkrB~clrn;rgen,

~ y') on d:}e TI:reml-smacrpr-.me:$.l:7!'Pperc '. e. Pri.2I.tors~ting4&Study,"a-'Ca1i6rat-mg"'5essi'ei\

,;w.a. . .

ie.l('f.<to revmw'Sh]1te ..ma~g-a~'\a4t'Al .........-..~st~

ITIle a s .€"Slra~~wn-,.j.l to

.c0ITes'P0n~ig~j.!J.~de:a~J;om;::~t'b 16

? .able .~arai;£JB:e:c~,~.~?--;-.2otW.cl;.Q1;he1's,, ~ Auschill & o~e~ 2..Q!J21-l1}...wrn.~h?'8~ number

\ \. FeanS'~ to~t];Ws1'ighter. H &.t.../( .~iti ti'ctp<:illts-wer.e.-r,ai'Id~sign-ed:.to three groups

of 13'vo1tnt;ers each (n=13 upper right canine). GroupA was treated with the over-the-counter technique,Group B with the at-home bleaching technique andGroup C with the in-office technique. The three groupswere screened, then treated according to the specificbleaching technique:

For Group A, the strips (Whitestrips, 5.3% hydrogenperoxide, Procter & Gamble Technical Centres Ltd,Egham, 1JK) were distributed and their applicationdemonstrated. The recommended wearing regimen was30 minutes twice a day, and the participants wereasked to rinse their mouth with water after wearing inorder to remove any remaining gel from the teeth.

.~'V_,,- '-~t~""'r.~Ji:..' .,~';i.j

Table 2: Side Effects and Patients' Acceptance Evaluated by Visual-analog Scale

Group A Group 8 Group C

Tooth sensitivity 2.62 :I:1.46 3.38 :I:1.66 2.85:1: 1.41 ./

Gingival irritations 0.85 :I: 1.82 0.38 :I:0.87 0.23 :: 0.44 ./

Patients acceptance 2.31 :I:1.93 1.46 :I:1.33' 3.31 :I:1.75*

': statistically significanrly different from each other (p<O.OI:Mann-Whitney-U.rest).

Auschill & Others: Clinical Comparison of Different Bleaching Techniques 159

not present at baseline or which worsenedduring the bleaching process.

baseline and after reaching the definedIt: . d of whiteness, impressions (DimensionGarant L, ESPE, Seefeld, Germany) of theupper right canine were taken. They wererinsed, dried and epoxy resin casts (BlueStar, GiITbach Dental GnliJH, Pforzheim,Germany) made. The cast was removed fromthe impression, trimmed, dried for 24 hours,fastened on a caITier, sputter coated withg','d palladium and examined under scan-r - electron microscope SEM (REM Leo40D VP, LEO Electron Microscopy Ltd,Cambridge, GB) at 15kV. SEM pictures atbaseline and after treatment of the uppercanine at 200x and 2000x magnificationwere obtained in order to evaluate enameltexture changes. SEM photographs of eachreplica were taken 4-mm labially from theincisal edge and half mesiodistally in ordert ..:;urethe same location on the tooth wasl. Threeexaminerscomparedeachofthepicture-pairs to find out whether a differencebetween the photographs evaluating enameltexture could be seen.

Statistical Analysis

Although the shade tab used was. not linearbetween the different tabs, a statisticalanalysis could still be performed since thel~ 'ine data were similar and did not differs< .,ficantly from one another (p :>0.05; byAi\lOVA).

The average values of the bleaching cycles,required time for the individual productsand the visual analogue scale were calcu-lated using the statistical program SPSS11.0.First, the data records were checked for.normal distribution using the Kolmogorowf 'nov test. Since they were not normallyQ :ibuted and significant differencesbetween the products were found usingAi'lo..VA{analy'~~_of ~ariance),_ the Mann- ~

WIll.ID.ey-U test ~Jiepen.dentsamples ~igure2.Mean~pplicationtim",(inminutes)ofthedifferentgroupsafterthevariousbleach-was ap~ied for statistical comparison Ing treatments and results of the statisticalanalysis t:p::; 0.05; ":p::; 0.01; "': p::;0.001among the t -- uSingMann-WMney-Utest).

ree groups. -

..~---

35 -.-.------!

30 r;Group A-~ ~--: .(:';~o~jp8

t8 GrQupCj

25

20ut..;:;>-()

15

i,;

~ ;,

t 6.63

10

-------

Figure 1. Mean number of cycles (z standard deviations in parenthesis) for the variousbleaching treatmen~s and results of the statistical analysis ('.p::; 0.05; ":p::; 0.01.. m:p::; 0.001 using Mann-Whitney-U test).

3500 ~--

3000

2500

:!:8.43

1000

500

RESULTS

A11~9 participants completed the study. The volunteersr .d in age from 21 to 68 years, with the average agebC"5 29.82 years. The participants were randomizedinto three groups. There were no statistically signifi-cant differences in the mean baseline shade, age orgender of the participants.

Efficacy of Shade Change

The shades of the three grou s did not differ si 'fi-.cantly at baselin~. eir values ranged from grade 9-15,with a mean value of 11.2:!:1.8in Group A, 1l.5:!:2.0 inGroup Band 1l.4:!:2.1 in Group C (p>0.05 by ANOVA).All three techniques proved to be effective at whitening.The mean treatment time required to achieve thedefined shade was 31.85 :t 6.63 cycles (= 958.46 :t

; -..;:::" ;;;.:.:~-"" IM'

- "r

160

"

"

Figure 3a. Clinical photograph before over-the-counter treatment.

Figure 4a: SEM photograph of enamel before over-the-countertreatment (2000x).

Figure Sa: SEM photograph of enamel before at-home treat-ment (2000x).

194.80 minutes) in Group A, 7.15 :t 1.86 cycles (=3043.85 :t 982.16 minutes) in Group Band 3.15 :t 0.55cycles (= 47.08 :t 8.43 minutes) in Group C (Figures 1and 2). Photographs of one participant (representingthe pre- and post-bleaching situations) are shown inFigure 3a and b.

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Operative Dentistry

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Figure 3b. Clinical photograph after 16 days of over-the-counter treat-ment.

Figure 4b: SEM phocograph of enamel after over-the-countertreatment (2000x).

.Figure 5b: SEM photograph of enamel after at-home treatment ~~OOO~ f..

Side-effects and Patients' Acceptance tIn order to record side effects and patients' acceptance

i

'.

.

..

.

.a visual analogue scale was used in which the extreme .

represented the limits of pain and acceptance. One en .~was labeled "no discomfort" or "best acceptance" (0),whereas, the other end was labeled "severe discomforljor "no acceptance" (10). Subjects were asked to marK

i ""O"-" ~ """'" _.

Auschill & Others: Clinical Comparison of Different Bleaching Techniques 161

Figure 6a: SEM photograph of enamel before in-office treat-ment (2000x.)

the position that best indicated their current opinion.All products yielded minimal side effects in the volun-teers. Transient problems documented by the patientsw re initial gingival irritation and slight thermal tooth

;itivity (Table 2). These symptoms were mild, tran-~, ,lt and reversible. Additionally, Table 2 shows theaverage values of patients' acceptance. .

Statistical Analysis of these data demonstrated thatthere was only one significant diflerence betweenOpalescence PF 10% and Opalescence Xtra Boost con-cerning acceptance (p~ 0.05, by Mann-Whitney-U-Test).

{\ll other ~:~arisons detected no significant differ-~(p>O.O y/1Analysis

The second part of the study showed that teeth treatedwith bleaching agents had no observable enamel sur-face texture changes when evaluated by the threeexaminers. No differences outside normal tooth varia-tions were visible when the texture of the epoxy resinreplica surface at baseline was compared with its cor-responding cast after bleaching, regardless of whether200x or 2000x magnification was used. Figures 4t mgh 6 present pre- and post-tr.eatment SEM photo-g: aphs of the enamel surface of each group.

DISCUSSION

To date, several studies have been performed in orderto observe the whitening effect of some products

'- /ollowing a defined bleaching time:In contrast, thisstudy examined thetirlie reqru~ed loo-achieve a definedbleaching result;.;fhus, this study design was chosen tot~'.'e into account the patients' claims of achieving visible

cening rather than using a product for a definedtUne.

It is difficult to compare the results of this study wit

~

data from the literature, because of significant variations in study design (in vivo vs in vitro), concentrationof active agents or length of exposure time. On th

)

Figure 6b: SEM photograph of enamel after in-office treatment(2000x).

other hand, to the best of our knowledge, there are nopublished studies available where these three tech-niques are compared with one another. "'- - -Efficacy

The precondition was to bleach six grades lighter thanbaseline value, which was achieved in each of the 39study teeth (Figures 3a and 3b). Thus, the clinical effi-.cacy rate for the volunteers in the groups W"'~ 100%Different methods of determining this tooth shadchange can be used (colorimeter, shade guide). In thisstudy, the VITA shade guide was used, because it is stillthe most commonly used method and is predictablewhen whitening teeth (Freedman, 1997).Side Effects

An additional objective of this study was to determinepossible side effects. Teeth 'and gum. sensitivity wereself-evaluated by the volunteers. Penetration ofbleachingagents into tooth hard tissue results in differentchanges in vital teeth. Numerous studies have shownthat pulpal reactions to bleaching agents are reversible(Cohen, 1979; Robertson & Melfi, 1980). They reportedno histological changes in the treated teeth when com-pared with the controls and concluded that vital bleachingwas harmless to pulpal tissues. A study by Seale,McIntosh and Taylor (1981) showed that treatment indogs with 33% hydrogen peroxide alone or with heatcaused obliteration of odontoblasts, hemorrhage,resorption and inflammatory infiltration, while heat

alone was not detrimental. Pulpal changes demon- ,A)Jstrated evidence of reversibility after 60 days. ..5};~

In this study, none of the three tested products neededlight for activation of the bleaching process. This may 4;,explain the low sensitivity values. Th~ at-home treat-

~

p:v..eL.tment caused slightly higher tooth sensitivity compared . _.A1~

v:.. to the over-the-counter and in-office treatments butt tl-'J.'jthis was not significant and had no consequence in ~'l. ,

patients' acceptance. This higher value could be y '

explained by the longer application time (in minutes)

-.' --~~_..~~"~; " ~

162

(Figure 2). Similar general observations could be maderegarding. gingival irritation. The over-the-counter

i treatment caused higher gingival irritation compared.j to the at-home or in-officetreatments, but again, no sig-JI nificant differences existed between the groups (Li &j others, 2003). These higher irritations could be due toI the fact that there was no monitoring of the over-the-

~ counter techniqueby a dentist. The strips were more

j. .J- irritating to the gingiva than the in-officetreatment,.. ¥ ~ which used a dam, and the at-home treatment, with its:. ~ individually desigIf"edguard. However, it should be kept

'Of

~

in mind that the irritation was mild and reversible in.".;-' each case and none of the volunteers had to resign.

QJJJ Additionally, visual inspection by the examiners11 f~ showed no signs of gingival inflammation or necrosisf;1{f\ after clinical treatment. The fact that, for many years,

carbamide peroxide and hydrogen peroxide solutionshave been investigated and used clinically to bleachvital teeth without incurring pulpal and gingivaldamage is an indication of its safety to these tissues.

~atients' AcceptanceThe at-home bleaching treatment was significantlymore accepted by patients compared with the in-office~method. When asked for reasons, the volunteers indi-cated that the at-home technique required less chair-time despite the in-office method being unde~tis?s control. It should be emphasized that valuesbetween zero and five indicate wide acceptance for allthree techniques. Thus, in principle, all products cITerecommenda

SEM

The second part of the study examined the effect oftooth bleaching agents on enamel surface. These obser-vations were based on scanning electron microscopicevaluations of epoxy casts of replicas made of the studyteeth (Leonard & others, 200la). All evaluations wereperformed by three examiners blinded to the status ofthe tooth. After the respective treatment times in eachgroup (16 days of active treatment in Group A, sevendays in Group B and one day in Group C), the surfacemorphology showed no 'noticeable changes compared tobaseline (Figures 4-6). Leonard and others (200 la)demonstrated that a regimen using a 10% carbamideperoxide solution had minimal to no effect on the enamelsurface. This is in accordance with other SEM findings(Haywood & others, 1991; Spalding, Taveira & de Assis,2003; White & others, 2003), where bleaching was con-sidered to be safe for enamel. In contrast, Bitter (1992)and McGuckin, Babin and Meyer (1992) found somegrooves on the enamel surface in their studies. Similarresults were presented by Hegedtis and others (1999),where atomic force microscopy pictures showed thatseveral grooves present in the enamel surface ofuntreated teeth became deeper after the bleaching pro-cedure. The increase in depth of the grooves was more

Operative DentisT

pronounced in the case of the higher concentrated soition (30% HP) after 28 hours of treatment. It was prsumed that the differences in. groove depth after tre~"1ment were caused by the difference in hydrog(peroxide concentration. However, in this study, t:treatment with 38% hydrogen peroxide took 60 minutin order to reach the desired result. Thus, in additionconcentration, the major difference. among the stuc:designs was the time of application of the active agelIn summary, the SEM results of this study showed thno differences between the test.ed bleaching methocould be observed with regards to surface textt:changes. However, if SlW'l1.d.be kept in mind that ptoxide could have not only affected the surface but a1the inner structure of the tooth. Without penetratithrough hard tooth tissues, it would be impossibletreat the intrinsic discolorations (Seale & others, 19EChemical release of calcium and other minerals v.observed (Mc Cracken & Haywood, 1996), whereas, 1clinical significance of this small amount was assUIT:not to be significant. It was not possible in the coursethis in vivo study to evaluate these internal areas a.more investigations are needed on this topic.

The results of this study indicate that each of ttreatments has certain advantages and disadvantagThe dentist should be familiar with all of them in or<to serve patIents best. The patIent can be treated wa single technique or a combination. For example, tpatient can start with the in-office technique to receimmediate results and continue with one of the oth,to save or extend the whitening.

;t'6~SIONS/

It can be concluded that all three tested techniques aeffective in removing intrinsic staining. In princip.the higher the concentration of the active ingredie'the faster- tooth ligntenlng occurs mr- minuteFolloWing the manufacturers' instructions (cycles),took an average of 16 days with the over-the-counbleaching technique, seven days when using the ~,home bleaching technique and, with the in-offibleaching technique, the result may be achieved in 0day. The side effects that appeared were reversibnone of the volunteers had to resign and there werestatistically significant differences among the grOUl-All techniques were well accepted, with a slight preftence for the home bleaching method. Additionally, ttested products had no evident effect on the surfamorphology of teeth when viewed under SEM at 20land 2000x magnification.

(Received 10 March 2004)

,..t Auschill & Others: Clinical Comparison of Different Bleaching Techniques

References

:\' .":,ill TM, Hellwig E, Schmidale S, Hannig M & Arweiler NB'2) Effectiveness of various whitening techniques and their

'. ,;:-ds on enamel surface Schweizer Monatsschrift furZahnmedizin 112(9) 894-900.

Bitter NC (1992) A scanning electron microscopy study of theeffect of bleaching agents on enamel: A preliminary reportJournal of Prosthetic Dentistry 67(6) 852-855.

Cohen SC (1979) Human pulpal response to bleaching proce-dures on vital teeth Journal of Endodontics 5(5) 134-138.

Dahl.JE& Pallesen U (2003) Tooth bleaching-a critical review,It' the biological aspects Critical Reviews in Oral Biology &

'icine 14(4) 292-304.

/ DauGun MP & Bartlett DW (2003) Safety issues when using car-V bamide peroxide to bleach vital teeth-a review of the litera-

ture European Journal of Prosthodontics and RestorativeDentistry 11(1) 9-13.

de Freitas PM, Basting RT, Rodrigues JA & Serra MC (2002)Effects of two 10% peroxide carbamide bleaching agents ondentin microhardness at different time intervals QuintessenceInternational 33(5) 370-375.

F: . :~roTS (1992) Bleaching teeth: History, chemicals. and(Jds used for common tooth discolorations Journal of

.,?ticDentistry 4(3) 71-78.

Freedman G (1997) Bleaching of vital teeth QuintessenceInternational 28(6) 426-427.

HaywoodVB (1992) History, sarety, and effectiveness of C'.lITentb1eachingtechniques and applications of the nightguard vitalbleaching technique Quintessence International 23(7) 471-488.

HaywoodVB & Heymann HO (1989) Nightguard vital bleachingQuintessence International 20(3) 173-176.

H "Jd VB, Hcuck VM & Heymann HO (1991) Nightguard... bleaching: Effects of various solutions on enamel texture

and color Quintessence International 22(10) 775-782.

Hegedtis C, Bistey T, Flora-Nagy E, Keszthelyi G & Jenei A(1999)An atomic force microscopy study on the effect of bleach-ing agents on enamel surface Journal of Dentistry 27(7) 509-515.

Kirk CE (1889) The chemical bleaching of teeth Dental Cosmos31 273-283.

L'I,."ten RE, Dunn WJ, Hartup GR & Murchison DF (2002), !r-concentration carbamide peroxide effects on surfacer:;ughness of composites Journal of Esthetic and RestorativeDentistry 14(2) 92-96.

Leonard RH Jr, Sharma A & Haywood VB (1998) Use of differentconcentrations of carbamide peroxide for bleaching teethQuintessenceInternational 29(8) 503-507.

163

Leonard RH Jr, Eagle JC, Garland GE, Matthews KP, Rudd AL& Phillips C (2001a) Nightguard vital bleaching and its effecton enamel surface morphology Journal of Esthetic andRestorative Dentistry 13(2) 132-139.

Leonard RH Jr, Bentley C, Eagle JC, Garland GE, Knight MC &Phillips C (2001b) Nightguard vital bleaching: A long-termstudy on efficacy, shade retention, side effects, and patients'perceptions Journal of Esthetic and Restorative Dentistry 13(6)357-369.

Li Y,Lee SS, Cartwright SL & Wilson AC (2003) Comparison ofclinical efficacy and safety of three professional at-home toothwhitening systems Compendium of Continuing Education inDentistry 24(5) 357-360, 362, 364.

Matis BA, Hamdan YS, Cochran lVIA& Eckert GJ (2002) A clini-cal evaluation of a bleaching agent used with and withoutreservoirs Operative Dentistry 27(1) 5-11.

Mc Cracken MS & Haywood VB (1996) Demineralization effectsof 10 percent carbamide peroxide Journal of Dentistry 24(6)395-398.

McGuckin RS, Babin JF & Meyer BJ (1992) Alterations inhuman enamel surface morphology following vital bleachingJournal of Prosthetic Dentistry 68(5) 754-760.

Pohjola RM, Browning WD, Hackman ST, IvIyersML & DowneyMC (2002) Sensitivity and tooth whitening agents Journal ofEsthetic and Restorative Dentistry 14(2) 85-91.

Robertson WD & Melfi RC (1980) Pulpal response to vital bleach-ing procedure Journal rf Enrlndnntirs 6(7) 6.15-649.

Seale NS, McIntosh JE & Taylor AN (1981) Pulpal reaction tobleaching of teeth in dogs Journal of Dental Research 60(5)948-953.

Spalding M, Taveira LA & de Assis GF (2003) Scanning electronmicroscopy study of dental enamel surface exposed to 35%hydrogen peroxide: Alone, with saliva, and with 10%carbamideperoxide Journal of Esthetic and Restorative Dentistry 15(3)154-164.

Turker SB & Biskin T (2003) Effect of three bleaching agents onthe surface properties of three different esthetic restorativematerials Journal of Prosihetic Dentistry 89(5) 466-473.

White DJ, Kozak KM, Zoladz JR, Duschner HJ & Gotz H (2003)Effects of Crest Whitestrips bleaching on surface morphologyand fracture susceptibility of teeth in vitro Journal of ClinicalDentistry 14(4) 82-87.

Zekonis R, Matis BA, Cochran MA, Al Shetri SE, Eckert GJ &Carlson TJ (2003) Clinical evaluation of in-office and at-homebleaching treatments Operative Dentistry 28(2) 114-121.

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