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Bowman CLINICAL Orthodontic Bonding: A Direct Approach s. Jay Bowman, D.MD. , M .S.D. Adju nct Assoc iate Professor, D epartment of Orthodontics, Saint Loui s University, Saint Louis, MO. , Straightwi re instru ctor, Th e University of Mi chi ga n, Ann Arbor, MI. Abstract Both direct and indirect bonding techniques have associated benefits and disadvantages. Mild improvements in bonding accuracy when using indirect bonding have been proposed to outweigh the additional procedures and costs. The advent of efficient pre-pasting and lightcured adhesives have improved direct bonding. It appears that to select one or the other technique is a more of practice management decision since excellent clinical results can be achieved with either. A comparison of the two techniques along with recommendations for simple improvements to the direct technique are presented. Keywords Direct bonding, indirect bonding, light cured adhesives. The advent of bonding adhesives for orthodontics has been one of the most significant changes in the history of the specialty. At the outset, the accuracy of di rect bonding of orthodontic brackets was restricted by the limited working time of the first generation of composite resin adhesives. In efforts to work within the constraints presented by the materials and to improve the accuracy of bracket placement, indirect bonding methods were developed. These procedures were also especially suited for lingual orthodontics due to significant variations in lingual dental morphology. With the subsequent introduction of light-cured ad hesives and their virtually limitless working time, more precise and yet efficient direct bonding became feas ible. Sondhi! has stated "proper bracket positioning is a c ritical part of co ntemporary orthodontic treatment, espec ially if some type of pre-adjusted prescription is utilized." This is true whether brackets are directly or indirectly placed. Despite the use of some type of traditional dental surveyor, intraoral measuring device (e.g., Boone ga uge, positioning jig) , or computerassisted "tooth-targeting system" for bracket placem ent and regardless if a technician, assistant , or the orthodontist places the brackets, it is the orthodontistof-record that is ultimately responsibl e for that precise positioning. Although there appea rs to be no differe nce in shear bond strength between brackets that are bonded directly or indirectly,2 there does seem to be a difference of opinion as to the level of accuracy that ca n be achieved with each. It would seem that brackets that are placed on dry stone models, using a precision "measuring gauge," in the quiet and well-lit confines of a laboratory (rather than the more turbulent oral environment), should be more accurately positioned. In fact, those with more than just a passing academic interest in the indirect technique claim that their bracket placement is, indeed, significantly more precise. 3 . 4 . s In co ntrast, Hodge and co-workers 6 concluded that mean bracket placement errors were similar for both directly and indirectly bonded appliances. Similar findings were reported by Koo et al. / however, the indirect technique did demonstrate greater accuracy for bracket hei ght. If, however, we are simply splitting h a irs (i.e., measuring fractions of millimeters in bracket position), then perhaps we should also take into equally serious consideration the much more substantial errors inherent to co ntemporary orthodontic treatment: errors in diagnosis/treatment plannin g, tolerances in manufacturing of brackets and wires, the fact that bracket prescriptions and bases are desi gned for the "average" tooth, and even the limited precision of arch wire bending during treatment. It is the accumulation of these errors that must be eliminated duri ng treatment in order to achieve an ideal result at the conclusion. a Ther efo re, any slight, but statistically significant improvement, derived from indirect bonding accuracy 137 J Ind O rth od Soc 2004; 37:137-145 may, at the e nd of the day, ofte n be c lini ca ll y in si gni f i ca nt. It i s somew h at lik e pur c has in g a compo nent ste reo system to li ste n to mu sic. You ca n pu rchase the most elaborate and sop hi sticated CD player or ampl ifi er, but if you have substanda rd spea kers or w iring, then the end resu lt is a less than idea l li stening experience; at least for the discerning aud iop hil e. In othe r words, an atte nti o n to detail in all aspec ts of orthodo ntic ca re, not ju st bracket placement, appears a reasonable expectati o n. Conseq uently, the choi ce between direct o r indirect bonding appea rs to be mo re of a practice management decision than a treatment imperative. As such, we mi ght then eva lu ate these two techniques in terms of a cost/ benefit analysi s without fea r that patient care will somehow be egreg iously affected by our se lect io n. Comparing the Clinical Procedures -At first glance, the clini ca l procedures for direct and indirect bonding are distinctly diffe rent; howeve r, they appea r to have many similariti es when compared to o ne anoth er in terms of the steps req uired fo r eac h: Direct bonding - isolation, access, visu ali zation , adh es ive app li cation , individu al bracket placement, flash-removal, and ad hes ive curing. Indirect bonding - i so l at io n, access, ad h es iv e appli cation , bracket tray placement, adhesive curing, and flash-removal. If li ght-cured ad hesives were pre-applied to the brackets prior to their placement o n teeth, fo r either the indirect or direct technique, then both methods would benefit from one less c lini ca l procedure. Otherwise, th e principal c lini ca l differences between these tw o techniques appea r to be threefold: the mode of bracket placement, cost, and flash-removal. Although a dental ass i sta nt ca n faci I it at e e ith er technique, direct bonding requires more chair side minutes. Thi s appea rs to be, at minimum , eq uitab ly balanced by time spent by a labo rato ry tech ni c ian perfo rmin g th e spec i ali zed procedures of bracket placement on mode ls and transfe r tray fabr icatio n fo r the indirec t technique. Co nsid e rin g that both techniques also use the same devices for iso lat io n of the dentition and th e sa m e ad hes i ves, then the difference in cost is directly related to mate ri als and eq uipment required for the labo ratory procedures of the indirect techniqu e. 138 Light-cured Adhesives Wh en using li ght-cured ad hes ives, the dental ass ista nt ca n initi all y place all of th e brackets o n the teeth. In thi s manner, the orth odonti st's chair side time is reduced to simpl y th e fi nal positioning of those brackets. Thi s does require a few mo re minutes th an the indirect placement of an entire tray filled w ith brackets. In either case, the orthodontist is still responsib le for the fin al positioning, w heth er that is accompli shed on a sto ne model o r directly o n the teeth. Conseq uentl y, the ort hodo nti st's time co mmitm e n t appears to equ iva lent for either technique, but the practitioner ca n decide to spe nd those few minut es ei ther in t he labo rato ry o r chai r side with the patient. A simil ar situ at io n ex ists for the remova l of the excess bonding ad hes ive that is ex pressed f ro m under the bracket as it is seated o nto th e tooth. For th e direct technique, this flash is removed just prior to the final positioning of eac h brac ket and befo re li ght-cure activation. At thi s stage, the soft ad hesive is easi Iy removed with simply a dental sca ler. In co ntrast, hard ened flash is removed only afte r curing of the ad hes ive for the indirect technique. Thi s may be a more tedious and time-co nsumin g procedure, often req uiring th e use of rotary instruments. If the add ed cost of materials , co mmitm ent to th e intermed iate laboratory procedures, and more difficult flash removal appea r balanced with a sli ghtly mo re accu rate bracket placement, then the se lect io n of indirect bonding is an easy one. If, however, th e o rthodontist realizes that some individu alized wirebending, bracket repositioning, and occasio nal use of a custom tooth positioner9,loare on the horizon, no matter the bonding tec hniqu e se lected, then a direct approac h may be ultimately simpl er, easier to teach auxili ari es, and mo re eco nomi ca l to co nsider. Especia ll y sin ce patients do not all ex hibit fully erupted dentitions {w i thout c rowdin g or rot ations} and they m ay i nadv e rt e ntl y sh ea r-off" a few br ac kets d u ri ng treatment, some direct bonding may be an inescapabl e eventu ality during typical orthodontic ca re anyway. II With that in mind, it i s no t the purpose of this co mmuni ca tion to rev isit th e num erous refe rences prov idin g sup erb instru ct ion in bracket bonding tec hniqu es,ll ,12, 13 but rather, to provide so m e enhancements to the already estab li shed protocols for direct bonding. Bowman Enhancements to Direct Bonding Isolation, Access, and Visualization Simp ly stated: if you cannot clearly see the tooth , you ca nnot accurately place a direct bond. Isolation of teeth to prevent co ntamination is also an issue for both direct and indirect bonding. In addition, ambient light Figure 1: An ope ratory li ght f ilte r (SafeVu, American O rth odo nti cs, In c., Sheboygan , WI), co nstru cted from translucent "o range" ac ryli c, prevents premature polymerization of li ght-cured bo ndin g ad hes ive and yet provides adeq uate li ght for accu rate bracket placement. Th e filter is rotated into place, over the li ght source, o nly when needed. Figure 3: Pre-pasting orthodontic brackets w ith li ght-cure adhesives, during assistant "downtime," provides an economi ca l method of improving the efficiency of direct bonding. After ad hesive is appli ed, the bracket is placed o nto a specially treated ca rd to preve nt loss of the adhesive when the bracket is subseq uently removed (Slippery Bond Ca rd , American Orthodontics, Inc., Sheboygan, WI). Cards are prepared with brackets spec ifically selected for a patient's individual treatment plan . These ca rd s are sto red in a " li ght safe" th at is transported to the ope ratory (Safe Box, American Orthodontics, Inc., Sheboygan, Wi). A "work box," constru cted from "orange" translucent ac ryli c, prevents polymerization of li ght-cure adhesives by ambient li ght during the pre-pasting process (Work Box, American Orthodo ntics, Inc., Sheboygan, WI ) Figure 2: An adjustable cheek expa nder (WYRED, Glenroe Tec hno logies, Inc., Bradenton, FL) prod uces both buccal and distal forces for improved access to posterior teeth durin g direct bonding. The terminal end of the spring stee l wire ca n be used as a "finger rest" to app ly mo re retraction to th e cheek on the side where brackets are being appli ed Figure 4. Direct bonding tray includes a "sli ppery" ca rd with pre-pasted brackets (Slipp e ry Bond Card , American Orthodontics, Inc., Sheboygan, WI). An "orange" acry lic cover over the bracket ca rd preve nts premature polymeri zation of the adhesive (Chairside Cover, American Orthodontics, Inc., Sheboygan, Wi) 139 J Ind Orthod Soc 2004; 37: 137- 145 Fi gur e 5 : Verti ca l o ri enta ti o n of brackets i s th e mo st problemat ic issue w hen d irect bo nd ing. A Boone gauge or so me derivative is ofte n used to measure the pos iti o n of th e edgew ise slot fro m the in cisa l edge o r cusp of th e tooth Figure 7: A f il ter " l o ll ypop" to prevent p remature po lymeri zatio n of light-cure ad hesive from amb ient li ght is held over the brackets immed iately after their ini tial placement. Thi s dev ice is removed w hen th e orthodo ntist adju sts th e fi nal bracket pos itio ns Figure 8 : App ly in g flu o ri de va rni sh (Duraflor, Ph ar m asc ience, Inc., Montrea l, Ca nada) immed iate ly after d irect bo nd procedu res helps to reduce enamel dem inerali zat io n les io ns. A thin coat ing of va rni sh is pa in ted o n the surfaces of the teet h, ad jacent to th e brac kets, usin g a mi ni ature spo nge app li cato r { • I o..' ~~I~ r · \ Figure 6: Alternat ives for vert ica l brac ket orientat io n: 1) a ve rti ca l slot gauge or disposab le measu rin g "sti ck" (cla mped into a needl e ho lder) is used to measure the incisa l edge ofthe brac ket to the incisa l edge or cusp of the toot h. 2) a di sposable measuring tape, also used to measure the bracket edge to the in cisa l edge or cusp. Both devices are placed d irect ly on the facia l surface of the tooth to red uce the rotatio nal errors inherent w ith Boo ne-t ype gauges (B racke t ga uges, G le nr oe Tec hn o log ies, Bra ndento n, FL; Butte rfly Brac ket System, Ame ri ca n Orthodo nti cs, Inc., Sheboygan, WI) Fi gure 9. A simp le tray set- up fo r the re-app licatio n of a flu o ri de va rni sh at 3-4 mo nth s in te rva ls durin g o rthodontics to help red uce the potenti al fo r ename l " sca rs." O nl y tooth brushin g, iso lation, and drying of th e enamel are required prior to rea ppli cati o n and operatory li ghts may prematurely reduce working time w hen li ght-cured adhesives are used. Therefo re, some simpl e improvements in th e clini ca l equi pment invo lved may signifi ca ntl y enhance d irect bo nd ing. A n ope rato ry li ght f il te r (SafeVu , A m e ri ca n O rthodonti cs, Sheboyga n, WI) (Fi gure 1) and adju stabl e li p/c h ee k ret rac t o r (WYRED re tr ac t or, G l enroe Technologies, Bradento n, FL)( Fi gure 2) are two simpl e 140 COMPLETE PRACTICE SYSTEM THAT WORKS ... AND WILL DO- IT ALLI USED GLOBALLY - _-. ... ---- .. ... ------ ...... -.. Simple to use ~- - Maximum results _.- .- . . _- .... . --... - - --------. - ... Save time -.-. ~- - Multiuser * Patient control * Office & financial * Imaging *Cepholametric analysis ...". --- .... ., ... ... It ...." •• - -. - " ....'4 . . . r . . . . .. * E.D.I * Correspondence * Web hosting ALL IN ONE PROGRAM For free brochure & demonstration please e-mail us at [email protected] JJ ORTHODONTICS MORIUI O RTHODONT I A BRACKET SYSTEM WIRES ROTH BRACKET SYSTEM MBT BRACKET NICKEL TITANIUM WIRES SYS~ ..'A '" EDGEWISE BAACKET SYSTEM' • .. _ ;s. (\ - .... - +. i ....!...;F!' • j1 - C-!= R~N1 IC BRACKET~ ~ GOILDEN BRACKETS ~ • .?i. • HEAT ACTIVATED WIRES TOOTH COLORED W IRES ~ ~ . ,UJ.!\:lI • • MOLAR BANDS STAINLESS STEEL WIRES "" COAXIA ~ WIRES NICKEL FREE BRACKETS ADHESIVES FANTASTIC BOND ELASTOMERICS JJ ORTHO PLIERS E CHAIN HEAVY WIRE CUTTER LIGATURE TIES PIN CUTTER ( ) ./ ARCH WIRE SLEEVE D I STAL END CUTliER .'" ,- ELASTIC THREAD UNIVERSAL PLlER;' SUPERLIGHT BOND ( CLASSIC BOND EXTRA ORAL APPLIANCES 1 ( / ) ... SEPERATORS ADAMS , . PLiER ROTATION WEDGES ALL ORTHODONTIC PLIERS JJ ELASTICS BEGG AUXILLARIES FACE BOW BEGG BRACKETS LOCK PINS BUCCAL TUBES OTH @DONl;I€ E I!:~STICS TYPODONT BAND MA-l'ERIALS V MICRO TORCH ROTATING SPRINGS TURRET UPRIGHTING SPR INGS ., JJ ORTHODONTICS MECHERY TOWER, CHALAKUDY - 680307 KERALA , INDIA PH : 914802700489, FAX : 91 4802705593 , MOBILE : 9846008283 , EMAIL : jjorthodontic@yahoo,com , WEB SITE : www, jj-dental. com BRANCHES (HENNAI MUMBAI NEW DELHI BANGALORE 85/12- PANTHEON ROAD SREERANGAM AVENUE, EGMORE, CHENNAI -8 PH : SREEJIlH - 9840428100 104 - IAI SANTHOSH MATH BUILDING PANTH NAGAR GHATKOOPER, MUMBAI . 75 PH : SEEIO - 9892081435 B- 479 SECTOR 19 NOIDA - 2013 1 PH : GEORGE 9891 166456 ASI MATHEW 9845599958 Bowman devices that were designed to improve this situation. The light filter is constructed of translucent " orange" acrylic and is placed directly in front of operatory lights to filter the light frequencies that would prematurely polymerize light-cured adhesives, while still providing adequate illumination for accurate bonding. bracket cards are then stored in a " light safe" storage box along with cards for other patients to be bracketed that week (Storage Box, American Orthodontics, Inc., Sheboygan, WI) (Figure 4). Although hydrophilic adhesives, glass ionomers with polyacrylic acid etch, and self-etch primers 14 have gained popularity in recent years, they are not without their own inherent limitations. For example, Swartz 15 has stated, "the preponderance of the studies investigating these materials with and without intentional water or saliva contamination suggests that they do not compensate for poor bonding procedure or saliva contamination." In other words, placing resin sealant or primer onto etched enamel prior to salivary pellicle formation is criti cal whether using a direct or indirect approach with any adhesive. 16 The vertical position of brackets is the most problematic aspect of direct bonding. In comparison, mesial-distal positioning and long-axis orientation have been reported to be just as accurate as found with indirect bonding. 7 Consequently, some type of measuring device would seem to be a prerequiste to precise positioning of brackets with the direct technique. A simple, yet adjustable, cheek expander produces not only lateral forces but also distal retraction of the lips to increase visibility and access to the posterior buccal segments. The force of expansion produced by the steel spring wire of the device can be adjusted and the terminal wire portion is used as a finger rest to improve retraction on only the side of the patient where a bracket is being directly applied. Pre-coating Brackets The introduction of light-cured adhesives, featuring increased working times, immediately improved the accuracy of direct bond placement. In fact, a dental assistant can place these adhesives on all of the brackets to be used for a particular patient, hours or days before their appointment. In this manner, the chair side time required for each patient is reduced . A " word box," constructed using "orange" light filter plastic, prevents ambient light from prematurely curing the adhesive as it is applied on each bracket (Work Box, American Orthodontics, Inc., Sheboygan, WI) {Figure 3). 17 An assistant selects only the specific brackets 18.19needed for a particular patient's treatment plan before applying the adhesive (e.g. premolar brackets are not pre-pasted if these teeth are to be extracted). The pre-pasted brackets are then placed on a specially treated card (Slippery Bond Card , American Orthodontics, Inc., Sheboygan, WI) to prevent adhesive dislodgement from the bracket base when the appliances are later removed from the card during direct bonding. The individual Accurate Bracketing The typical device used to measure vertical bracket position is the Boone gauge or some derivation thereof (Bracket Height Gauge, Glenroe Technologies, Bradenton , FL) (Figure 5). In general, these gauges are to be placed at a right angle to the labial surface of the tooth in the anterior region and parallel to the occlusal plane in the posterior. Unfortunately, undesired deviations in bracket position are possible if the device is not angulated properly. An alternative is to measure along the facial surface of the tooth from the incisal edge of the bracket, instead of the slot, to the incisal edge or cusp (r(Figure 6). In this manner, rotational errors are minimized; however, a different bracketpositioni ng chart for your bracket prescription wi II need to be created. 11 End Game: Flash Removal, Curing, and Fluoride Varnish An "orange" acrylic filter can be held over the seated brackets to prevent premature polymerization from ambient light until the orthodontist performs final positioning (Mouth Shield, American Orthodontics, Inc., Sheboygan, WI) (Figure 7). Excess bonding material or "flash " is easily removed during final bracket positioning and prior to polymerization of the adhesive. A simple dental scaler hand instrument is placed in the bracket slot to orient it on the tooth surface and serves double duty to remove the expressed adhesive around the bond margins. This is undoubtedly less timeconsuming and potential more comfortable for the patient than using a rotary instrument to remove hardened adhesive, as required by the indirect technique. There are a number of options available for initiating the polymerization of light-cured adhesives (e.g. 143 J Ind Orthod Soc 2004; 3 7:1 37-1 45 halogen,20 LED, plasma lights, and lasers). Recently, argo n lase rs have been shown to signifi ca ntly decrease enamel demineralization. 21.22 Th erefore, if th e cost of these lase rs becomes affordable, they may become more prevalent in orthodontic practice. Until th at time, the routin e app li cat io n of a fluoride dental varnish (Dur af lor, Pharm asc i e nce , Montreal, Canada ) immed iately after the placement of brackets, with reapp lication every 3-4 months during treatment, has been demo nstrated to provid e some reduction of enamel demi neral ization. 23,24 A thin coating of varnish is painted on the exposed enamel of the facial surface, immediately after li ght curing of brackets and while the teeth are still dry {Figure 8). 25 The added minute or so of time and low cost of this material is worthwhile, especia lly if it mi ght preve nt or at least diminish th e prevalent and unaesth eti c dilemma of enamel scars. Periodi c re-application of varnish only requires simple tooth brushing and isolation. For th at reason, it can be easily incorporated into routine orthodontic adjustment visits (Figure 9). Direct or Indirect: Question? Is That Really the Both direct and indirect methods of orthodontic bracket placement can produce accurate and favorable results. Some difference in procedures and costs are the major determinants in selecting one method over the other. Objective self-assessment of finished cases (e.g., ABO Discrepancy Index,26 PAR Index 27 ) and/or peer-reviewed evaluations (e.g., American Board of Orthodontics or Angle Society examination , study clubs, case presentations), combined with an attention to detail in all aspects of orthodontic care, seem to be just as important electives. Their utilization may help to avoid stagnation in practice and repetition of the same errors, while simultaneously optimizing improvements in finished results for orthodontic patients. In other words, the only way to assess the accuracy of your finished cases, including your chosen bonding technique, is to measure the outcomes and then fine-tune your treatment procedures as a result. *Orange box system, SafeVu li ght filter, and Butterfly System are available from American Orthodontics, Inc., 1714 Cambridge Ave. , Sheboygan, WI. 53082. **WYRED cheek retractor and bracket position gauges are available from Glenroe Technologies, 1912 44th Ave. East, Bradenton, FL 34203. 144 *** D ur af lor fluorid e varnish from Pharmascience Laborato ri es, In c., 10 Orchard Pl ace, Tenafly, NJ 07670 is ava ilable from most dental suppli ers. Commu n i cations S. Ja y Bowman 1314 West Milham Ave. Portage, MI 49024 e-mai l: drjwyred@aol. com Re ferences 1. Sondhi A. The impli cations of bracket se lecti o n and bracket pl acement on finishing details. Sem Orthod 2003;9:155-64. 2. Yi GK, Dunn WJ, Taloumis LJ. Shear bond strength comparison betwee n direct and indirect bonded orthodontic brackets. Am J Orthod Dentofac Orthop 2003;124:577-81. 3. Sondhi A. Effici ent and effective ind irect bonding. Am J Orthod Dentofac Orthop 115:352-9. 4. Machata B. Indirect bonding: Custom base - A vehicle for change. Am Orthod. Good Practi ce 2003;4{1 ):5-7. 5. Melsen B, Biagg ini P. The Ray Set: A new technique for precise indirect bonding. J Clin Ortho 2002;36:648-54. 6. Hodge TM, Dhopatkar AA, Rock WP, Spary DJ. A randomized clinical trial comparing th e accuracy of direct versus indirect bonding pla ce ment. J Orthod 2004;31 (2):132-7. 7. Koo Be, Chung e, Vanarsdall RL. Comparison of the accuracy of bracket placement between direct and indirect bonding techniques. Am J Orthod Dentofac Orthop. 1999;116:346-51. 8. Sachdeva R. Personal communication, 2001. 9. Bowman SJ, Carano A. Short-term, intensive use of the tooth positioner in case finishing . J Clin Orthod 2002;36:216-9. 10. Bowman SJ. Fine-tuning case completion with the new ProFlex po sitioner. AOAppliances , etc. 2003;7{1 ):1-2. 11. Mclaughlin RP, Bennett JC, Trevisi HJ. Systematized orthodontic treatment mechanics, Mosby, S1. Loui s, MO, 2001. 12. M cNamara JA Jr. , Brudon WL. Orthodontics and dentofacial orthopedics, Needham Press, Ann Arbor, MI , 2001. 13. Gianelly T. Bidimensional technique: Theory and practice. GAC International , Islandia, NY, 2000. Bowman 14. Sirirungrojying S, Saito K, Hayakawa T, Kasai K. Efficacy of using self-etching primer with a 4MET A/MMA- TB B resi n cement in bond i ng orthodontic brackets to human enamel and effect of saliva contamination on shear bond strength. Angle Orthod 2004;74:251-8. 15. Swartz ML. Orthodontic Bondi ng. Pract Rev Orthod Select 2004;16(2)1-4. 16. Swartz ML. Treatment efficiency. Summary by Owen Nichols. Pac Coast Soc Orthod 2004;Spring: 32-34. 17. Korn M. Saving time with the orange box bonding system. Am Orthod. Good Practice 2002;3(1 ):4. 18. Bowman SJ, Carano A. The Butterfly system. J Clin Orthod 2004;38:274-287. 19. Bowman SJ, Addressing concerns for finished cases: The development of the Butterfly bracket system. Part I. Interview by Ashok Karad . J Ind Orthod Soc 2003;36:73-75. 20. Bowman SJ, Maston PRo Infection control for curing lights. J Clin Orthod 2000;34:484-486. 21. Anderson AM, Kao E, Gladwin M, Benli 0, Ngan P. The effects of argon laser irradiation on enamel decalcification: An in vivo study. Am J Orthod Oentofac Orthop 2002;122:251-9. 22. Noel , L, Rabellato 1, Sheats RD. The effect of argon laser irradiation on demineralization resistance of human enamel adjacent to orthodontic brackets: an in vitro study. Angle Orthod. 73:249-258,2003. 23. Vivaldi-Rodrigues G, Oemito CF, Bowman , S1, Ramos, AL. The effectiveness of a fluoride varnish in preventing the development of white spot lesions. World J Orthod. In press. 24. Bowman SJ. Scar tactic: Fluoride varnishes fight decalcification stains in orthodontic patients. Orthod Prod 2002;March:32-5. 25. Bowman SJ. Use of a fluoride varnish to reduce decalcification. J Clin Orthod 2000;34:377-9. 26. Casko JS, Vaden JL, Kokich VG, Oamone J, James RO, Cangialosi T1, Riolo ML, Owens SE Jr, Bills ED . Objective grading system for dental casts and panoramic radiographs . American Board of Orthodontics. Am J Orthod Oentofacial Orthop. 1998;114(5):589-99. 27. Richmond S, Shaw WC, O'Brien KO, Buchanan IB, Jones R, Stephens CD, Roberts CT, Andrews M. The development of the PAR Index (Peer Assessment Rating): Reliability and validity. Eur J Orthod. 1992;14(2): 125-39. 145