ORIGINAL ARTICLE

White spot lesion formation after treatment withfull-coverage rapid maxillary expanders

Ahmet Yagci,a Yasemin Nur Korkmaz,b Suleyman Kutalmis Buyuk,c Filiz Yagci,d and Aykan Onur Atillae

Kayseri, Ordu, and Ankara, Turkey

aAssoUnivebReseUnivecAssisUnivedProstUniveeOrthkara,All autentiaSuppoordinAddreFak€ulhotmSubm0889-Copyrhttp:/

Introduction: The aim of this study was to evaluate whether treatment with full-coverage bonded acrylic splintexpanders causes formation of white spot lesions using quantitative light-induced fluorescence. Methods: Theexperimental group underwent rapid maxillary expansion (RME) (n 5 16; 6 boys, 10 girls; mean age,14.1 6 2.2 years), and the control group received no orthodontic treatment (n 5 17; 9 men, 8 women; meanage, 20.7 6 1.1 years). Quantitative light-induced fluorescence images of the RME patients were takenbefore cementation and after decementation of the appliances. The images of the control group comprisedquantitative light-induced fluorescence images taken 3 months apart. Four parameters were calculated for 10anterior teeth. Results: Between cementation and decementation, statistically significant differences werefound in all 4 parameters in the RME group, whereas no significant changes were found in any parameters inthe control group. A comparison of the measured parameters between the RME and control groups showed sta-tistically significant differences. Conclusions: Patients treated with a full-coverage bonded appliance tended todevelopmore white spot lesions than did the control subjects. (Am JOrthod Dentofacial Orthop 2016;149:331-8)

White spot lesion formation is a common sideeffect of orthodontic treatment. Gorelicket al1 showed that the prevalence values of

white spot lesion formation were 49.6% in patientstreated with fixed orthodontic appliances and 24% inan untreated control group. When fixed appliances areplaced on the teeth, areas of plaque accumulation arecreated, and maintenance of adequate oral hygienebecomes a challenge for the patient. Studies have shownthat plaque accumulation is increased in patientsreceiving orthodontic treatment with fixed appliances.2

Increased plaque accumulation results in increased

ciate professor, Department of Orthodontics, Faculty of Dentistry, Erciyesrsity, Kayseri, Turkey.arch assistant, Department of Orthodontics, Faculty of Dentistry, Erciyesrsity, Kayseri, Turkey.tant professor, Department of Orthodontics, Faculty of Dentistry, Ordursity, Ordu, Turkey.hodontist, Department of Prosthodontics, Faculty of Dentistry, Erciyesrsity, Kayseri, Turkey.odontist, Osmanli Dental Center, Republic of Turkey Ministry of Health, An-Turkey.thors have completed and submitted the ICMJE Form for Disclosure of Po-l Conflicts of Interest, and none were reported.rted by a grant from the Erciyes University Scientific Research Projects Co-ation Unit, number TSA-11-3585.ss correspondence to: Ahmet Yagci, Erciyes €Universitesi Dis Hekimli�gitesi, Ortodonti A.D. Melikgazi, Kayseri, Turkey; e-mail, dtahmetyagci@ail.com.itted, April 2015; revised and accepted, August 2015.5406/$36.00ight � 2016 by the American Association of Orthodontists./dx.doi.org/10.1016/j.ajodo.2015.08.015

cariogenic activity and demineralization of the enamel.Since translucency is related to the degree of enamelmineralization, white spot lesions are seen as the firstclinical indication of initial enamel demineralization.3

These lesions form rapidly over a period of about4 weeks.4,5

When orthodontic treatment is completed and fixedappliances are removed, white spot lesions may eitherremineralize or persist. Some lesions even progress andproduce cavitations that require restoration. Persistentor progressive lesions result in undesirable esthetic man-ifestations. Thus, white spot lesions should be found asearly as possible.

Various types of orthodontic appliances enhanceplaque accumulation, despite patients' efforts to ensureadequate oral hygiene. White spot lesion formation caneasily occur in the cariogenic environment adjacent tothe irregular surfaces of orthodontic appliances such asbrackets, wires, loose bands, orthodontic elastomericmaterials, or other frequently used appliances for correc-tion of Class II and Class III malocclusions and rapidmaxillary expansion (RME) devices.

RME is a commonly used procedure for the treatmentof a maxillary transverse deficiency because transverseocclusal discrepancies between the maxillary andmandibular arches are relatively frequent, with a preva-lence of 8%.6 The full-coverage bonded acrylic splintexpander is an RME device developed over the years toprevent the unwanted effects of conventional

331

332 Yagci et al

appliances. It is both a tooth-borne and a tissue-borneappliance with enhanced anchorage and is favorablebecause it prevents unwanted tooth tipping and pro-vides vertical control, which can be necessary duringmaxillary expansion in patients with increased verticaldimensions.7,8 Despite its beneficial properties, thebonded appliance can lead to white spot lesionformation through microleakage and increased plaqueaccumulation.

Quantitative light-induced fluorescence (QLF) is amethod of white spot lesion detection that evaluatesthe fluorescence levels of lesions. It provides measure-ments of mineralization changes in demineralized andsurrounding sound enamel that are directly related tofluorescence levels. To date, various studies have beenperformed to determine the effect of orthodontic treat-ment on white spot lesion formation using QLF.9-13

However, no studies have been carried out on theeffect of full-coverage bonded acrylic splint expandertreatment on white spot lesion formation.

Therefore, the aim of our in-vivo study was to eval-uate the effect of full-coverage bonded acrylic splintexpander treatment on white spot lesion formationwith QLF.

MATERIAL AND METHODS

The local research ethics committee of the Depart-ment of Orthodontics, Faculty of Dentistry, of ErciyesUniversity in Kayseri, Turkey, granted ethical approvalfor the study. Informed consent was obtained from thepatients and the parents of those under 18 years ofage before the study. The sample population comprisedorthodontic patients treated at the Department ofOrthodontics of Erciyes University. The experimentalgroup consisted of 16 patients (6 boys, 10 girls) with amean age of 14.1 6 2.2 years, and the control groupincluded 17 patients (9 men, 8 women) with a meanage of 20.7 6 1.1 years. No patient had deciduous,congenitally missing, or extracted teeth. A power anal-ysis was performed using G*Power software (version3.0.10; Franz Faul Universitat, Kiel, Germany). Basedon a 1:1 ratio between the groups, a sample size of 16subjects in each group was calculated to give morethan 85% power to detect significant differences withan effect size of 0.30 at a significance level of a5 0.05.

The experimental group included patients with atransverse maxillary deficiency in addition to an entireorthodontic malocclusion. The patients underwentRME with a full-coverage bonded acrylic splint expanderthat contained a hyrax screw (Dentaurum, Pforzheim,Germany), with an activation of 2 turns a day (0.2 mmper turn) for the first week and 1 turn a day after the first

March 2016 � Vol 149 � Issue 3 American

week until adequate expansion was reached, as recom-mended by Zimring and Isaacson.14 After reaching thefinal transverse maxillary width, the acrylic splintexpander was kept in the mouth as a fixed retainer for1 month. The appliance was then uncemented. Themean duration that the appliance was attached to theteeth included the phase of expansion until the tips ofthe palatal cusps of the maxillary first molars contactedthe tips of the buccal cusps of the mandibular first mo-lars, with amonth of fixed retention (65.106 3.06 days).

The acrylic plate of the expander covered the crownsof all teeth and the palate, leaving only a 1-mm gapbetween its borders and the gingival margins to facilitateadequate cleaning at the gingival margins by the patient.Glass ionomer luting cement (Ketac Cem radiopaque;3M ESPE, Neuss, Germany) was used for bonding theappliance to the teeth in accordance with the manufac-turer's instructions. To prevent bond failure, the patientswere warned not to drink acidic beverages and not to eathard food. After cementation of the expander, thepatients were shown how to clean their mouth withthe expander in place and advised to brush their teethafter each meal. No additional fluoride applicationswere given.

The control group consisted of subjects who hadnever received orthodontic treatment. They wereeducated on proper oral hygiene techniques and, simi-larly to the experimental group, they were asked to brushtheir teeth after each meal. Supplemental fluoride appli-cations were not given during the time interval whentheir QLF images were captured.

The QLF images of the RME patients were takenbefore cementation (T0) and after decementation (T1)of the full-coverage bonded acrylic splint expander(Fig 1). The T0 and T1 images of the untreated controlgroup comprised QLF images taken 3 months apart.The QLF images were captured with a QLF-D Bilumina-tor 2-camera system (Inspektor Research Systems,Amsterdam, The Netherlands) and stored automaticallyon a computer with image-capturing software (C3v1.20; Inspektor Research Systems) (Fig 2). Images ofthe tooth surfaces were all captured with the same cam-era position and angulation. All images were taken in adark room by the same examiner (Y.N.K.).

In each subject, the buccal surfaces of 10 anteriorteeth (maxillary incisors, canines, and premolars) wereassessed for white spot lesions. One investigator(Y.N.K.) who was blinded to the groups evaluated eachimage using analysis software (QA2 v1.20; InspektorResearch Systems) (Fig 3). Four parameters were calcu-lated for each tooth: percentage of fluorescence losswith respect to the fluorescence of sound tooth tissue(DF [%]), maximum loss of fluorescence intensity in the

Journal of Orthodontics and Dentofacial Orthopedics

Fig 1. Full-coverage bonded rapid maxillary expander.

Yagci et al 333

whole lesion (DFmax [%]), lesion area withDF equal to orsmaller than a –5% threshold (A [px2]), and percentage offluorescence loss with respect to the fluorescence ofsound tissue times the area that indicated lesion volume(DQ [%px2]). The QLF images were then reanalyzed aftera 2-week interval by the same examiner (Y.N.K.). Mea-surements made with the analysis software showed ahigh correlation coefficient, with a value of 0.91 for in-traobserver reliability. The calculated parameters wereused to compare the experimental and control groups.

Statistical analysis

The Wilcoxon signed rank test was used to comparethe parameters at the beginning and end of the studyfor each tooth in both groups. Differences between themeasurements at T0 and T1 were calculated for eachgroup, and the Mann-Whitney U test was used for com-parison of these differences between the groups. Thelevel of statistical significance was set at P\0.05.

RESULTS

In the RME treatment group, white spot lesion for-mation was observed in all teeth except the maxillary

American Journal of Orthodontics and Dentofacial Orthoped

right and left canines and the right second premolars.The fluorescence levels in the enamel decreased duringthe study period, indicating mineral loss. From the 16subjects in the RME group, a total of 160 buccal surfaceswere assessed by QLF. Table I demonstrates the means ofthe DF, DFmax, A, and DQ scores as well as the P valuesof the 10 maxillary anterior teeth of the patients treatedwith a full-coverage bonded acrylic splint expander.

The scores for each parameter in the control groupare given in Table II. The control group had lower scoresfor all parameters measured. Changes between T0 andT1 were not significant for any parameter. In otherwords, no parameters were significantly affected in the170 buccal surfaces assessed in the 17 control subjects,indicating no statistically significant demineralization(P .0.05).

A statistical comparison of the differences in theparameters between T0 and T1 between the RME andcontrol groups is shown in Table III. The results indicatedthat the changes in most of the measured parameterswere significantly different between the groups, exceptin the maxillary right and left canines and the right sec-ond premolars.

The numbers of white spot lesions found in thegingival, middle, and incisal thirds of the teeth afterdebonding of the full-coverage bonded acrylic splintexpander in the RME group are shown in Table IV.

DISCUSSION

White spot formation is a specific clinical problem fororthodontic patients treated with fixed orthodonticappliances. Demineralization beneath orthodonticbrackets and bands has always been a major concernto orthodontists. This study showed that white spotlesion formation is also a concern for patients treatedwith orthodontic bands and brackets, since other fixedappliances can lead to the formation of white spotlesions. Demineralization under a full-coverage acrylicsplint expander may be associated with inadequateoral hygiene, dissolution of cements in the oral environ-ment, seal breakdown, and poor bonding strength.

Patients receiving orthodontic treatment have signif-icantly more white spot lesions than do untreated sub-jects. The prevalence of white spot lesions inorthodontic patients has been reported to be between2% and 96%.1,15,16 Mizrahi15 showed that white spotlesions are more common in maxillary incisors andmandibular first molars, whereas Gorelick et al1 foundthat white spots tend to form on the maxillary incisors,especially the lateral incisors. In accordance with previ-ous results, the incisors were highly affected by whitespot lesions in our study. The maxillary left and rightcanines were the least affected teeth.

ics March 2016 � Vol 149 � Issue 3

Fig 2. A, QLF-D Biluminator 2 camera (Inspektor Research Systems, Amsterdam, The Netherlands);B, image-capturing software (C3 v1.20, Inspektor Research Systems).

334 Yagci et al

Numerous appliance types for RME have beendesigned and applied to date. A full-coverage appliancedesign was preferred in this study to provide efficientmaxillary expansion. The posterior bite-block effect offull-coverage appliances induces bite closure through

March 2016 � Vol 149 � Issue 3 American

the intrusive forces produced by the masticatory mus-cles.17 The occlusal coverage of this design acts as a pos-terior bite block and controls unwanted buccal tippingand vertical eruption of the posterior teeth during expan-sion. This mechanism prevents increments in the vertical

Journal of Orthodontics and Dentofacial Orthopedics

Fig 3. Analyzing software (QA2 v1.20; Inspektor Research Systems) used for the measurements.

Yagci et al 335

dimension. With a full-coverage design, the expansionforces are distributed to the entire maxilla, and the skel-etal effect of the expansion is improved. The full-coverage design also improves the attachment of theappliance by bonding to all teeth. On the other hand,the design of the appliance may lead to demineralizationthrough potential food accumulation because of its bulkystructure and protruding edges. Additionally, failure inbonding could produce white spot lesions. The numberof white spot lesions that were detected in the gingivalthird of the buccal surface after full-coverage appliancetreatment was higher than the number of lesions in themiddle and incisal thirds of the teeth in our study. Thesedata might indicate that lesions occur primarily becauseof plaque accumulation at the gingival surfaces in condi-tions of insufficient oral hygiene. Failure of the bondingmaterial seems to be less likely to cause white spot lesionformation, considering the smaller number of lesions un-der the appliances. Banded RME devices could be an op-tion for patients susceptible to white spot lesions becausethey are easy to clean, and the bands are placed only onthe first premolars and first molars.

Cements are used widely in orthodontics for theattachment of bands and bonded appliances to teeth.Glass ionomer cement was chosen for the cementationof acrylic splint expanders in our study. It was introduced

American Journal of Orthodontics and Dentofacial Orthoped

by Wilson and Kent18 and is preferred in orthodonticsbecause of its anticariogenic properties, which arerelated to the release of fluoride.18,19 It is a hybrid ofsilicate and polycarboxylate cements and acts as achelating agent in tooth structures.20 Despite its desir-able properties, mastication forces can cause cementa-tion failure between the teeth and the full-coveragebonded acrylic splint expander, thus resulting in micro-leakage and white spot lesion formation. Microleakage isdefined as the clinically undetectable passage of bacte-ria, fluids, molecules, or ions between a cavity wall anda restorative material.21 Polymerization shrinkage ofadhesive materials can cause microgaps between thetooth surface and the adhesive material, thus resultingin microleakage and white spot lesion formation.22

Several studies have investigated the decalcificationcaused by microleakage under orthodontic bracketsand bands.22-26 Similar to these studies, microleakagemight have had a role in white spot lesion formationunder the acrylic splint expanders used in our study.Further studies with different agents for cementationshould be designed to investigate the effect ofdifferent bonding materials on white spot lesiondevelopment.

Currently, there are many techniques to assess carieslesions. Visual inspection, probing, and radiographs are

ics March 2016 � Vol 149 � Issue 3

Table I. Comparison of DF, DFmax, DQ, and A values between T0 and T1 in the RME group with the Wilcoxon si ned rank test

Tooth*

DF (%) DF (%) DF (%) DFmax (%) DFmax (%) DFmax (%) DQ (%px2) DQ (%px2) DQ px2) A (px2) A (px2) A (px2)

Mean T0 Mean T1 P value Mean T0 Mean T1 P value Mean T0 Mean T1 P lue Mean T0 Mean T1 P value

11 �1.51 6 2.71 �4.35 6 4.37 0.004z �1.56 6 2.8 �5.75 6 6.11 0.004z �5.18 6 10.04 �50.12 6 77.94 0. 4z 0.87 6 1.74 6.5 6 10.62 0.02y

12 �4.15 6 4.05 �6.97 6 5.55 0.004z �5.87 6 6.79 �13 6 11.37 0.001z �177.18 6 491.09 �610.25 6 1146.44 0. 3z 18.12 6 47.29 51.62 6 91.48 0.006z

13 �4.07 6 9.62 �4.84 6 10.07 0.297 NS �8.06 6 22.02 �9.18 6 23.17 0.469 NS �479.56 6 1506.11 �450.56 6 1619.5 0. 9 NS 21.18 6 53.75 16.25 6 40.5 0.578 NS14 �2.53 6 3.96 �6.75 6 3.95 0.002z �5 6 8.63 �11.75 6 11.23 0.01y �247.06 6 518.87 �315.81 6 556.72 0. NS 27.37 6 55.25 24.43 6 46.8 0.497 NS15 �2.51 6 4.11 �4.56 6 5.29 0.055 NS �4.75 6 9.39 �7.25 6 11.18 0.164 NS �311 6 1096.43 �335.18 6 791.25 0. 9 NS 27.12 6 91.79 31.62 6 71.36 0.129 NS21 �3.13 6 4.42 �5.42 6 5 0.002z �4.81 6 7.47 �9.37 6 11.75 0.002z �253.5 6 634.16 �1070.5 6 2963.21 0. 6z 25.87 6 64.55 79.37 6 200.06 0.01y

22 �2.2 6 3.44 �4.61 6 4.42 0.008z �3 6 4.93 �7.87 6 8.95 0.004z �104.37 6 349.88 �197.87 6 357.92 0. y 12.18 6 38.62 22.68 6 38.96 0.164 NS23 �2.2 6 6.05 �4.23 6 7.34 0.063 NS �5.12 6 14.04 �7.5 6 14.3 0.313 NS �1060.62 6 3419.68 �2360.3 6 9157.37 0. 3 NS 57.37 6 179.78 92.25 6 342.09 0.313 NS24 �0.85 6 2.32 �3.6 6 3.84 0.02y �1.43 6 4.25 �4.87 6 5.73 0.03y �24.81 6 97.37 �73.37 6 175.25 0. 8z 3.5 6 13.73 8.81 6 20.58 0.008z

25 �1.08 6 3.01 �5.64 6 4.63 \0.001§ �1.56 6 4.57 �8.43 6 9.14 \0.001§ �6.62 6 23.03 �187.62 6 367.43 \0. 1§ 0.68 6 2.27 17.75 6 33.45 \0.001§

*FDI system of notation.yP\0.05; zP\0.01; §P\0.001.NS, Nonsignificant.

Table II. Comparison of the DF, DFmax, DQ, and A values between T0 and T1 in the control group with the Wilco on signed rank test

Tooth*

DF (%) DF (%) DF (%) DFmax (%) DFmax (%) DFmax (%) DQ (%px2) DQ (%px2) DQ px2) A (px2) A (px2) A (px2)

Mean T0 Mean T1 P value Mean T0 Mean T1 P value Mean T0 Mean T1 P lue Mean T0 Mean T1 P value11 �1.81 6 3.42 �2.44 6 3.56 0.313 NS �2.76 6 5.67 �3.94 6 7.32 0.125 NS �26.58 6 63.58 �95.05 6 293.23 0.1 6 NS 3.23 6 7.08 10.41 6 28.91 0.156 NS12 0 6 0 �0.99 6 2.23 0.25 NS 0 6 0 �1 6 2.26 0.25 NS 0 6 0 �2.29 6 5.21 0.2 NS 0 6 0 0.41 6 0.93 0.25 NS13 �0.37 6 1.55 �0.99 6 2.21 0.5 NS �0.35 6 1.45 �1.23 6 2.77 0.25 NS �0.35 6 1.45 �11.76 6 34.67 0.2 NS 0.05 6 0.24 2.05 6 6.06 0.25 NS14 �0.92 6 2.77 �0.77 6 2.17 1.00 NS �1.35 6 4.28 �1 6 2.87 1.00 NS �22.47 6 83.59 �6.76 6 24.96 0.5 S 2.35 6 8.07 1 6 3.64 0.5 NS15 �0.41 6 1.72 �0.84 6 2.41 0.5 NS �0.47 6 1.94 �1.58 6 5.03 0.5 NS �2.05 6 8.48 �37.17 6 145.97 0.5 S 0.29 6 1.21 4.52 6 17.42 0.5 NS21 �1.82 6 2.94 �2.8 6 3.1 0.156 NS �2.29 6 3.82 �3.47 6 3.97 0.109 NS �22.52 6 75.1 �44.52 6 99.75 0.1 8 NS 3.23 6 10.35 6.58 6 13.16 0.148 NS22 �1.51 6 2.82 �1.86 6 3 0.438 NS �1.82 6 3.46 �2.47 6 4.15 0.313 NS �5.58 6 12.89 �40.76 6 103.47 0.1 5 NS 0.82 6 1.84 6.11 6 14.96 0.125 NS23 �0.29 6 1.21 �0.32 6 1.35 1.00 NS �0.29 6 1.21 �0.35 6 1.45 1.00 NS �0.58 6 2.42 �1.29 6 5.33 1.0 NS 0.11 6 0.48 0.23 6 0.97 1.00 NS24 �1.69 6 6.98 �1.9 6 7.85 1.00 NS �4.35 6 17.94 �4.64 6 19.16 1.00 NS �957.88 6 3949.45 �1075.82 6 4435.73 1.0 NS 33.29 6 137.27 33.17 6 136.79 1.00 NS25 �1.37 6 4.5 �1.88 6 3.08 0.625 NS �2.58 6 9.46 �2.29 6 3.94 0.625 NS �73.35 6 295.8 �22.58 6 52.73 0.6 5 NS 4.23 6 16.21 3.41 6 8.19 0.625 NS

*FDI system of notation.NS, Nonsignificant.

336Yagciet

al

March

2016�Vol149�

Issue3

American

JournalofOrthodontics

andDentofacialO

rthopedics

g

(%

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00004611120003310000

x

(%

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Tab

leIII.Co

mparison

ofthechangesin

theDF,

DFm

ax,D

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Avalues

betweenthegrou

pswith

theMann-Whitney

Utest

Tooth*

ControlD

FT1

-TO

RMEDF

T1-TO

DFT1

-TO(%

)Co

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Fmax

T1-TO

RMEDFm

axT1

-TO

DFm

axT1

-TO(%

)Co

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QT1

-T0

RMEDQT1

-T0

DQT1

-T0

(%px

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ControlA

T1-T0

RMEAT1

-T0

AT1

-T0

(px2)

Mean

Mean

Pvalue

Mean

Mean

Pvalue

Mean

Mean

Pvalue

Mean

Mean

Pvalue

11�0

.636

1.82

�2.836

3.65

0.01

y�1

.176

2.42

�4.186

4.81

0.03

y�6

8.47

623

6.26

�44.93

676

.12

0.14

0NS

7.17

623

.09

5.62

610

.45

0.35

5NS

12�0

.996

2.23

�2.816

3.34

0.01

y�1

62.26

�7.126

7.2

0.00

1z�2

.296

5.21

�433

.066

984.05

0.00

9z0.41

60.93

33.5

681

.66

0.01

y

13�0

.616

1.88

�0.766

3.02

0.52

1NS

�0.886

2.17

�1.126

4.86

0.79

0NS

�11.41

633

.32

296

436.31

0.67

4NS

26

5.84

�41.17

0.77

3NS

140.15

60.92

�4.226

4.41

0.00

2z0.35

61.72

�6.756

9.56

0.00

6z15

.76

58.62

�68.75

653

9.7

0.00

2z�1

.356

4.45

�2.936

48.52

0.01

y

15�0

.426

1.44

�2.056

3.97

0.18

3NS

�1.116

3.27

�2.5

69.84

0.26

4NS

�35.11

613

7.49

�24.18

613

42.65

0.05

9NS

4.23

616

.21

4.56

113.73

0.06

2NS

21�0

.976

2.17

�2.296

2.93

0.03

y�1

.176

2.67

�4.566

5.7

0.03

y�2

26

108.61

�817

623

77.9

0.35

4NS

3.35

613

.83

53.5

613

9.5

0.46

7NS

22�0

.356

1.48

�2.416

3.93

0.07

6NS

�0.646

2.52

�4.876

8.22

0.03

y�3

5.17

610

0.96

�93.56

189.96

0.22

2NS

5.29

614

.54

10.5

624

.58

0.53

5NS

23�0

.036

0.14

�2.036

3.6

0.15

1NS

�0.056

0.24

�2.376

6.86

0.15

1NS

�0.7

62.91

�129

9.68

658

99.8

0.15

1NS

0.11

60.48

34.876

176.83

0.15

1NS

24�0

.216

0.87

�2.756

4.35

0.01

y�0

.296

1.21

�3.436

6.18

0.08

8NS

�117

.946

486.28

�48.56

699

.34

0.03

y�0

.116

0.48

5.31

69.57

0.00

5z

25�0

.516

3.37

�4.566

4.18

0.00

4z0.29

67.06

�6.876

8.44

0.00

4z50

.766

270.03

�181

636

7.38

0.01

y�0

.826

14.69

17.066

33.35

0.01

y

*FDIsystem

ofno

tatio

n.yP

\0.05

;zP\0.01

.NS,

Non

sign

ificant.

Table IV. Number of white spot lesions in the gingival,middle, and incisal thirds of the teeth after debondingof the appliances in the experimental group

Tooth*

15 14 13 12 11 21 22 23 24 25Total(n)

Total(%)

Gingival third 6 8 3 7 5 7 6 5 6 7 60 68.18Middle third 3 4 1 3 2 2 2 0 2 2 21 23.86Incisal third 0 1 0 0 2 1 1 0 0 2 7 7.95

*FDI system of notation.

Yagci et al 337

American Journal of Orthodontics and Dentofacial Or

thoped

the traditional caries detection methods; these have theweaknesses of being subjective and inadequate to detectearly caries lesions. Early detection of these lesions isrequired for early treatment. Therefore, various methodshave been introduced to detect incipient caries lesions.Digital radiography, fiber-optic transillumination, theelectronic caries monitor, DIAGNOdent (KaVo, Biberach,Germany), alternating current impedance spectroscopy,and QLF are some methods developed over the years.The QLFmethod was chosen to investigate white spot le-sions in our study because of its previously demon-strated efficiency and sensitivity for white spot lesionassessment.9,27,28 Along with the presence of lesions,progression and regression can also be assessed by thistechnique.

Attention should be drawn to the prevention of whitespot lesions, rather than their treatment after formation.Demineralization of the enamel may take place becauseof bacterial plaque retention on the enamel for a pro-longed time.1 Therefore, it is important to maintain suf-ficient oral hygiene during orthodontic treatment. Alimitation of this study was that the experimental groupconsisted of adolescents with a mean age of14.1 6 2.2 years, and the control group comprisedyoung adults with a mean age of 20.7 6 1.1 years.The control group might have maintained better oralcare than the experimental group because of the age dif-ference, and this might have affected the white spotlesion formation rate. The eating habits of the groupscould also have differed because of the age difference.Adolescents are more likely to have cariogenic food intheir diet than are adults; this could have affected whitespot lesion formation.

The patients in this study were advised to brush theirteeth after each meal, and no additional preventionmeasures were recommended. Studies have shown thatusing different fluoride reinforcements during ortho-dontic treatment with fixed appliances decreases whitespot lesion formation.4,29 Additional fluorideapplications during treatment can be suggested to

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patients receiving acrylic splint expander treatment forthe prevention of decalcification. Furthermore, fluorideapplication before treatment could be an option todecrease the number of demineralized lesions. Furtherstudies are needed to analyze the effect of fluoridemeasures during the treatment period or just beforecementation of the appliance on the prevention ofwhite spot lesions. Patients with poor oral hygieneshould not be treated unless they can maintainadequate oral hygiene. In our study, bonding of thebrackets was performed immediately after debondingof the full-coverage appliance so as not to impede thetreatment. Nevertheless, further research concerningthe reversibility of white spot lesions with the applicationof fluoride after debonding of the full-coverage appli-ance and before bonding of the brackets should bedesigned.

CONCLUSIONS

We investigated whether full-coverage bondedacrylic splint expanders can cause white spot lesion for-mation. The results showed that patients treated with afull-coverage bonded acrylic splint expander tended todevelop more white spot lesions than did the controlsubjects.

Because of the decalcification seen after treatment,maintaining oral hygiene at a high level and applicationof remineralizing agents during treatment is necessaryto prevent white spot lesions.

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