Evolution of Orthodontic Brackets

8/12/2019 Evolution of Orthodontic Brackets

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Evolution of Orthodontic Brackets

1& 2

Professors

Department of Orthodontics

KSR Institute of Dental Science & Research,

Tiruchengode, Tamil Nadu.

ABSTRACT:

Orthodontics distinguishes and differs itself from the other

branches of medicine by its widespread use of an array of devices

made of almost all the biomaterials known. From metals to plastic and

from ceramics to composites, these materials bring beauty and health.

Brackets evolutions from the introduction of pin and tube to lingual,

magnetic and self ligating brackets are rapid in pace and play a

significant role in advancement of Orthodontic field. Though, we all

are using recent brackets which are currently available in the markets,

it is important to know the past history of brackets which was usedearlier. Thus, this article reviews the history of various orthodontic

brackets and it's advantages and disadvantages. We suggest that

many more review studies should come aiming at the biocompatibility,

aesthetics and treatment results of each bracket. Such studies will

help the practitioner to decide the bracket selection for his treatment

plan.

1 2Dr. Tamizharasi , Dr. Senthil Kumar

IntroductionOne of the most important passive components of

fixed appliances is brackets. They are merely handles for

attachment of the force producing agents. Brackets canaffect the directions of the force vectors when torque,angulations, and in/out are built into the brackets.Orthodontic treatment is based upon specific forceapplications to the dentition, the maxilla and the mandible.In order to obtain these forces, orthodontic brackets areattached to the teeth. Previously, brackets were banded tothe teeth. But, after, the introductions of bonding resin,brackets are rarely banded to the teeth.

HistoryIt is difficult to imagine that there was a period in

Orthodontics before the invention of brackets. Yet this wasthe situation when Angle developed and perfectedtreatment procedures with his E arch which provided noaxial tooth control. During this time he also advocated thepre-treatment extraction of teeth and devised methods toclose extraction spaces "sans" brackets.

1The pin and tube appliance overcame the weakpoint in his E arch. Thus the prototype of bracket wasconceived. The problems of pin and tube appliance wereovercome in ribbon arch appliance by Angle with theintroduction of first orthodontic bracket the ribbon arch

1bracket . It had a vertical slot facing occlusally and wasmade in gold. The next major advancement in bracket

design that had withstood the test of time was the first

edgewise bracket with a horizontal slot (0.022 x 0.028).Ever since many modifications had come in bracket designand in bracket material.

ClassificationBrackets can be classified according to:-1. Width of bracket

a. Mesiodistally narrow ex., Ribbon arch bracket,Begg bracket

b. Mesiodistally wide ex., Edgewise bracket, Straightwire bracket

2. Slot of bracketa. Horizontal slot ex., Edgewise bracketb. Vertical slot ex., Begg bracket

3. Materialsa. Metal Stainless steel, Gold, Titanium, Nickelb. Plasticsc. Ceramicsd. Combination Metal reinforced plastics, metal

reinforced ceramics4. Movement of tooth

a. Tipping movement Begg bracketb. Bodily movement - Straight wire bracketc. Tipping & Bodily movement Combination

bracket, Tip-Edge bracket5. Ligation of bracket

a. Conventional ligation Edgewise bracket, Beggbracket

b. Self-ligation- Edgelok bracket, SPEED bracket

JIADS VOL -1 Issue 3 July - September,2010 |25|

REVIEW ARTICLE


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Description of Brackets

Ribbon Arch BracketThe ribbon arch appliance introduced in 1915,

was the next step in the evolution of tooth alignment

devices. It was actually the first bracket, as such, to be usedin an orthodontic appliance. In the ribbon arch appliance,the tube principle was abandoned for the bracket principle.The mesial and distal walls of the tube were removed. Thusthese brackets had a vertical slot facing occlusally incontrast to the Begg bracket which faces gingivally.

Universal Bracket2The name universal only connotes that the

bracket is effective to move and control tooth movement inall planes. It is truly a light wire bracket, designed to beused with light wires, but for stability purposes, heavy wires

are also accepted. This in itself makes the bracketuniversal in its implementation. It has two separate slotsto receive single or multiple wires for the various toothmovements. The bracket also has wings that enhance thewire action.

Begg BracketThese are modified ribbon arch brackets, which

are narrow mesio-distally and carry a vertical slot usually of0.022 size. The ribbon arch brackets designed by Angle

3were placed inverted by Begg with the slot facinggingivally. The round arch wire is loosely fitted and held inplace by a lock pin or ligature tie wires. This is responsiblefor the free tipping and sliding of teeth during the initialstages of treatment. But, because of the narrow bracketand round wire, apical movements are not possible withoutthe use of auxiliary springs.

Modern Begg BracketDr. William J. Thompson introduced the Modern

4Begg Technique in the year 1981. It comprises of theadvantages of the Begg light wire technique and StraightWire technique. The gingival, or ribbon-arch slot isdesigned to permit maximum crown and root tippingmovements and the edgewise slot is designed for precise

final detailing. These bracket types provide adequatemesiodistal width for optimal rotations, tipping and torque.The base of the four-stage bracket is bevelled to reduce thepossibility of friction or binding with the arch wire. Thespecifications for torque, tip, and in-out placement vary foreach tooth.

Tip Edge BracketDr. Peter C. Kesling designed the Tip Edge

5bracket . From his experiences with differential toothmovement for 30 years and a thesis written in 1968, hedetermined that is necessary for each tooth to tip freely

either mesially or distally-not in both directions. The face of

the edgewise bracket has been changed to permit freecrown tipping followed by controlled root uprighting.

Lateral extensions of the bracket behind the archwire provide maximum rotational control even when the

tooth is tipped. The wings are lingual to the archwire andtherefore not visible. Each bracket has a vertical slot toaccept rotating or uprighting springs, power pins and jigsfor accurate direct bonding. The slot is rectangular (0.020x 0.020) with both the gingival and incisal ends chamferedto facilitate the insertion of auxiliaries from either direction.

Ceramaflex II 256 Begg BracketsThe most exciting addition to the Begg appliance

component list, are the ceramic brackets. TP OrthodonticsInc markets it as Ceramaflex II 256 Begg brackets. Thisbracket is polycrystalline alumina and is manufactured byinjection moulding. The bonding surface has apolycarbonate base with a slot to enable easy debondingand to avoid enamel fracture that occurs with ceramic

2brackets .

Edgewise BracketAngle's fina l achievement, the edgewise

appliance, was the culmination of many years of effort andmany different appliance designs attempting to place theteeth according to his line of occlusion. The original

1edgewise bracket as designed by Angle was a soft goldbracket with a 0.022 x 0.028 slot which was readilydeformed by the forces of occlusion and by tying ligature

wires to the bracket.

Various modification of edgewise brackets are:

Single Width BracketIt was designed to overcome the problem of tooth

rotation. He devised soldered gold eyelets to be placed inthe bands.

Twin BracketThe next development was the joining together of

two edgewise brackets on a common base. It was named1

after the originator of the idea Swain . The Siamese bracketquickly gained popularity for use on upper central incisorsand on molar teeth. Its main advantage was its ability toeffect most of the tooth rotation without the use of auxiliaryeyelet ties. After many years another evolutionary step wasthe curving of the base of the twin bracket to confirm to thecurvatures of the canines and premolar.

Lewis BracketLewis developed another approach to the problem

of efficient tooth rotation. He soldered auxiliary rotationarms that abutted against the bracket itself and thus offereda lever arm to deflect the archwire and rotate the tooth. Itdoes not interfere with occlusogingival deflections of the


Evolution of Orthodontic Brackets Tamizharasi & Senthil Kumar


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archwire. The next development in the Lewis rotationbracket was the curving of the base and wings of thebracket to conform to the canine and premolar teeth.

Vertical Slot Lewis BracketA refinement in the Lewis bracket has been the

incorporation of a 0.020 x 0.020 vertical slot, makingpossible the use of uprighting springs to correct axialinclinations if needed.

Steiner BracketThis bracket incorporated flexible rotation arms

which afforded a rotational effect. It works satisfactorily aslong as the flexible arms do not take on a permanentdeformation.

Broussard Bracket1It was developed by Garford Broussard . It is a

conventional bracket with a closed, rectangular, vertical slot0.018 by 0.046 which is formed when the bracket iswelded onto the band material.

Other Modifications:1SVED MODIFICATION

SINGLE EDGEWISE BRACKET WITH VERTICAL SLOTSINGLE EDGEWISE BRACKET WITH VERTICAL SLOT ANDNARROW LIGATURE SLOTSINGLE EDGEWISE BRACKET WITH VERTICAL SLOT ANDWIDE LIGATURE SLOT

LEE-FISHER EDGEWISE BRACKETMODIFIED LEE-FISHER EDGEWISE BRACKET

Preadjusted Edgewise BracketIn this bracket system the need for the first, second

and third order bends has been reduced by producing acustom bracket for each tooth, in which a combination ofvarying thickness of bracket base, inclinations of slot andtorque of the slot are used to minimize the wire bending forideal archwire. These characteristics for each tooth arecalled the appliance prescription or building treatmentinto the appliance.

1. Andrews Prescription6Dr. Lawrence F. Andrews introduced the Straight Wire

Appliance to Orthodontic profession in 1970. Hisappliance was based on six keys to normal occlusion.He divided the appliance as nonprogrammed,partially programmed and fully programmedappliances. Non programmed brackets are withoutslot or base inclination. Partly programmed bracketcontains 220 slot inclinations. Fully programmedbrackets have 220 base inclination.

2. The Roth Set-up7

The Roth Set-up was introduced in the year 1976. Thepurpose of the Roth setup was to provide idealized

tooth positions prior to appliance removal that wouldallow the teeth in most instances to settle innonorthodontic normal's studied by Andrews. Healtered the prescription of the Andrews appliance to

allow the teeth to be placed in a slightly overcorrectedposition in all three planes.

3. Swain Modification of The Roth Set-up

Swain altered the prescription of the Andrewsappliance to what he thought would allow the teeth tobe placed in a slightly overcorrected position in all threeplanes of space but not so far overcorrected that the

1teeth would not settle into an idealized position .

4. Vari-simplex Brackets

The Vari-Simplex Discipline includes a specific bracket8system used in case treatment. Dr. Wick Alexander

described it in the year 1978. The Vari-Simplex systemis designed for 0.018 bracket slots and 0.017 wire.Though 0.022 brackets can also be used, he feelspatient comfort is improved, treatment time isdecreased, and the teeth are more easily moved intotheir proper positions with the 0.018 slot.

5. Bennett & Mclaughlin Technique9The authors Richard P. McLaughlin & John C. Bennett

introduced this technique, in the year 1995. Theyproduced a Theoretical Bracket Placement Chart bymeasuring the distance from the incisal or occlusaledge to the centre of the clinical crown. Values at

+0.5mm and +1.0mm were added for larger teeth,and values at -0.5mm and -1.0mm for smaller teeth.

6. Segmental Arch Technique

Dr. Charles J. Burstone introduced this technique whichuses the Medium Diamond Twin brackets of the Orthos

10prescription. His Vertical Tube Cuspid Bracket is verypopular featuring an horizontal auxiliary tube.

7. Bioprogressive Technique11Dr. Robert Murray Ricketts introduced the

Bioprogressive therapy in the year 1976. There are 3combinations - standard progressive setup where

torque is built into upper incisor and all 4 canines, full-torque setup where torque built in lower molars andpremolars, triple-control setup with rotational control.

8. Linear Dynamic System

The linear dynamic System is a simplified version of the11Bioprogressive therapy given by Dr. James J. Hilgers

in the year 1987. According to him, if double or triplebuccal tubes on upper or lower molars are used idealorthodontic occlusion can be achieved.

9. The Level Anchorage System

It consists of a banded or bonded edgewise appliance

with built-in tip, torque, and offset and an analysis andtreatment-planning chart with a step-by-step treatment




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procedure for seven different extraction and nonextraction choices.

10. The ORTHOS System12Dr. Craig Andreiko , applied computer-aided

engineering technology to orthodontic appliancedesign in developing the Orthos System, truly incited aworldwide movement away from pre-adjustedappliances based on 1960s metrology.

11. The Bios System

Bios is a light-wire, higher-torque version of theOrthos appliance system. Dr. Jim Hilgers designed the

13Bios system to allow for earlier torque control withlighter wires. It differs from the Orthos prescription byvirtue of its increased torque in upper incisors and in themandibular posterior segment, as well as lingual root

torque in upper and lower cuspids.Lingual Brackets

14Dr. Kinya Fujita introduced the Mushroom arch wireappliance in the year 1979. In the lingual bracket, theopening of the slot was set on the occlusal surface of theteeth in order to facilitate the fitting of the wire. The groovefor lockpin insertion was set mesiodistally in the slot and anauxiliary groove was set in the occlusogingival direction tofacilitate correction of the mesiodistal tipping of the teeth.

Self Ligating Brackets

Self ligating brackets were introduced in theseventies with the Edgelok bracket. These brackets havethe advantage of aesthetics and comfort. The possibility ofpuncture wounds from ligature ties is nil. The mostcommon used brackets are Mobil-Lok brackets, Insert

15bracket, SPEED brackets , Activa Brackets, DamonSL Brackets , Time Bracket etc., Shortened chair time andslightly less incisor proclination appear to be the significant

16advantages of self-ligating system . Recently, theintroduction of active and passive self-ligating brackets haspresented a challenge to the speciality because of the novelligation mode and the potential alterations in load andmoment expression during mechanotherapy.

Bioefficient BracketsDr. Anthony D. Viazis designed the Bioefficient17brackets in the year 1995. These triangular brackets are

twin brackets with a single-slot type. It was designed toprovide the first differential stiffness bracket toaccommodate the new, differential-force superelastic wire.

Adhesive Precoated BracketsThe orthodontic resources of United and the adhesive

expertise of 3M have combined to create the first AdhesivePrecoated metal brackets. It does not set until it's light cured.

Bracket Materials

The first orthodontic attachments were made of

gold. Since the introduction of Stainless steel it has

remained the most widely used material in the manufactureof orthodontic attachments. Plastics were introduced in thelate sixties and ceramics have been introduced in the mideighties. Titanium bracket have solved the problems of

nickel sensitivity, corrosion, and inadequate retention. It'sone-piece construction requires no brazing layer, and thusit is solder and nickel-free. TP orthodontics has introducedthe Nu-Edge bracket in the year 1997. It uses cobaltchromium alloy that is essentially nickel free.

Polycarbonate brackets were described and testedby Newman in 1969. Later,polyurethane, fiber-reinforced,

18and filler-reinforced brackets became available . Theyhave limited popularity because of clinical problems ofstaining rendering them unaesthetic, distortion andtearing of the bracket particularly from torsional forces.More efforts are directed improving the strength ofpolycarbonate/ polymeric brackets by reinforcing the weakplastic matrix. These types of brackets are reinforced withceramic, glass or even with metal inserts.

Ceramic brackets were first introduced in 1987and it has found wide acceptance and still holds morepromise. The number of problems such as excessive bondstrength, enamel fracture on debonding, brittleness of thebracket and surface finish has been largely addressed inthe second generation of ceramic brackets.

Magnetic brackets were introduced by Kawata et19al ., in 1987. The magnetic material that first employed

clinically was a cast alloy consisting of 25% to 30%chromium, 15% to 25% cobalt, and 45% to 60% iron.

Recently, a new material that contains a rare earth metalsamarium has been included in the magnet. The magnethas at the present time the highest available coercivity andmaximum energy product.

Bracket WidthThe wider the bracket, all other things being equal,

the easier it will be to generate the moments needed tobring roots together at extraction sites or to controlmesiodistal position of roots in general. The wider bracketreduced both the force needed to generate the momentand the contact angle, and is thus advantageous for space

closure by sliding.Despite their advantage, wider brackets also have

disadvantage. The wider the bracket on a tooth, thesmaller the interbracket span between adjacent teeth, andtherefore the shorter the effective length of the archwiresegments between supports. The maximum practical widthof a wide bracket is about half the width of a tooth, andeven narrower brackets have an advantage when teeth aremalaligned, because the greater interbracket span givesmore springiness.

Bracket Slot

Good torque is possible with steel wires and 18miledgewise brackets. The original 22-slot would have some




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advantage during space closure but would be a definitedisadvantage when torque was later added. If only steelwires are to be used, the 18-mil slot system has advantageover the larger bracket size. NiTi alloys with springback

and resistance to permanent deformation have overcomesome of the alignment limitations of steel wires in 22 mil slotbrackets, while rectangular NiTi and Beta-Ti wires offeradvantages over steel for the finishing phases of treatment

17and torque control .

Bracket BasesOne of the most important factors in retention of

an Orthodontic bracket is type of bracket base. The mostcommon bracket bases are perforated bases, foil meshbases, photoetched bases and integrated cast type bases.The use of small, less noticeable, metal bases helps avoid

gingival irritation. The wire size of the mesh as well as thesize and topography of spot welds are also considered inbond strength.

Today's favourite bases are die cut from laminatesmade of a fine mesh, pressed under heat to a foil that canhave various thickness. A still promising forward step isthe micromechanical retention, achieved by coating thebases with porous metal powder.

Coating of bonding agents on bracket bases alsoincreases retention. The coating process increasesmechanical retention by creating undercuts on the top andsides of the wire mesh. The brackets are also silanated as afinal step which creates higher additional bond strength

due to chemical bonding of the bracket with the adhesive.

RecyclingThough there are still concerns about the possible

increased risk of cross infection, yet recycled brackets arestill used to reduce the cost per case. Brackets can berecycled either by application of heat to burn off theadhesive or by using chemical solvents to strip off theadhesive.

DiscusssionAlthough Orthodontia started to function without

the use of brackets, yet today it has become an integralpart of it. With the advent of aesthetic brackets andaesthetic archwires the field is becoming more refined dayby day. But, still metal brackets have more advantagesthan aesthetic brackets in reducing the friction duringretraction and also facilitates easy debonding procedures.

The invention of self ligating brackets hasshortened the treatment duration, reduces the patient visitsand enhances better patient co-operation. The recentintroduction of zirconia-based ceramics as a restorativedental material has generated considerable interest in the

20dental community. According to Koutayas SO et al .,zirconia based orthodontic brackets can be technologically

21feasible. Heravi F states that in future, the reduction in the

curing time and change in light direction may increase thebond strength and reduce enamel fracture duringdebonding. The bracketless invisible aligner technique hasbeen considered as a new developed orthodontic technique

since its appearance during the period of late 1990s.22According to Bai YX there have been many opportunitiesfor further development and clinical application for thistechnique with the developments of material sciences,computer software and hardware technology, rapidprototyping techniques, et al.

23Regarding bracket materials, Eliades T states thatmanufacturing techniques might be modified to include laser-welding methods and metal injection molding. Estheticbracket research will involve the synthesis of high-crystallinitybiomedical polymers with increased hardness and stiffness,decreased water sorption, and improved resistance todegradation. Further, he describes that new plastic brackets

23might incorportate ceramic wings .24Sims MR has viewed the future of brackets from a

technical point. According to him, in the next millennium,the genome revolution and knowledge of proteinproduction and control could lead to the genetic correctionof dentofacial anomalies and pain-free, biomolecularmethods of malocclusion correction and long-term stability.A fundamental change would be in the abolition of bracketsystems and their replacement with preprogrammedmicrochips driven by computers, and the control of PDLblood vessels and cells by pharmacological targeting.Future survival of this profession will depend on a radically

different specialist who will be educated with apostgraduate curriculum based on molecular biology and

24computer engineering .

Summary And ConclusionOrthodontia has attained unmeasurable goals in

the past century. Today, we are surprised to know that therewas a period when Orthodontia was functioning withoutbrackets. The advancement of the size, shape, materialand technology of brackets of today is amazing. Hence, it isnecessary for the Orthodontist to keep in pace with rapidchanging technology of Orthodontic brackets and

materials to be a successful clinician.Though various authors have predicted the future

of brackets in their own ways yet at present toothmovements produced by bracket-archwire combinationwill be the ultimate method for years to come. Periodicreviews are necessary for the orthodontist to update hisknowledge as well as to decide a better treatment planand provide better comfort zone to the patient. Thisarticle has only reviewed the evolution of brackets. Wesuggest that many more review studies should comeaiming at the biocompatibility, aesthetics and treatmentresults of each bracket. Such studies will help thepractitioner to decide the bracket selection for histreatment plan.




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Referrences:1. Tamizharasi P. Update of Orthodontic brackets.[Thesis]. India: Annamalai

University; 1999. 3p.2. Tamizharasi P. Update of Orthodontic brackets.[Thesis]. India: Annamalai

University; 1999. 184p.

3. Begg & Kesling. Begg Orthodontic Theory and Technique. 100-1002 p.4. Flowers. Variations of Begg Technique. Am J Orthod Dentofacial Orthop.1961;47(3):288-291

5. Peter C. Kesling. Expanding the horizons of the edgewise-arch wire slot.Am J Orthod Dentofacial Orthop. 1988;94(1):26-37.Andrews LF. Thestraight-wire appliance. Br J Orthod. 1979;6(3):125-43.

6. Ronald H. Roth. The Straight-Wire Appliance. J Clin Orthod. 1987; 9:632-642.

7. R.G. Alexander. The Vari-Simplex Discipline: Part I Concept andAppliance Design. J Clin Orthod. 1983; 6: 380-392.

8. Richard P. McLaughlin & John C. Bennett. Bracket placement with thePreadjusted system. J Clin Orthod. 1995; 5: 302-311.

9. Burstone. Horizontal tube cuspid bracket. Clinical Impressions 1996; 5:3,11.

10. Robert Murray Ricketts. Bio-Progressive therapy as an answer toorthodontic needs- Part I. Am J Orthod Dentofacial Orthop. 1976; 241-268.

11. Dr. Craig Andreiko. Orthos. A New Technology that frees you to focus on

the art of Orthodontics. Clinical Impressions. 1995; 3-7, 5-8.12. Hilgers. Bioprogressive Simplified. Part 2-The Linear Dynamic System. J

Clin Orthod. 1987; 10: 716-34.13. Kinya Fujita. New Orthodontic treatment with lingual bracket mushroom arch

wire appliance. Am J Orthod Dentofacial Orthop. 1979; 76(6): 656-675.

14. G. Herbert Hanson. The SPEED System: A report on the development of anew edgewise appliance. Am J Orthod Dentofacial Orthop. 1980; 78(3)243-65.

15. Stephanie Shih-Hsuan Chen et al. Systematic review of self-ligatingbrackets. Am J Orthod Dentofacial Orthop. 2010; 137(3): 362-7.

16. R. G. Alexander. The Vari-Simplex Discipline: Part I Concept and

Appliance Design. J Clin Orthod.1983;6:380-392.17. Julia Krauss, Andreas Faltermerier. Evaluation of alternative polymer

bracket materials. Am J Orthod Dentofacial Orthop. 2010; 137(3); 362-7.18. Kawata, Hirota, Sumitani et al. Clinician's corner Property of Magnetic

brackets. Am J Orthod Dentofacial Orthop. 1987; 9:241-248.19. Koutayas SO, Vagkopoulu T, Pelekanos S, Koidis P, Strub JR. Zirconia in

dentistry: part 2. Evidence based clinical breakthrough. Eur J Esthet Dent.2009 Winter; 4(4):348-80.

20. Heravi F. Bayani S. Changes in shear bond strength of ceramic and stainlesssteel brackets with different visible light curing times and directions. AustOrthod J. 2009 ;25(2):153-7.

21. Bai YX, Wang BK. Opportunities and challenges during the development ofthe orthodontic invisible aligner technique(in Chinese). Hua Xi Kou QiagYi Xue Za Zhi 2007; 25(6): 521-4.

22. Eliades T. Orthodontic materials research and applications: part 2. Currentstatus and projected future developments in materials and biocompatibility.Am J Orthod Dentofacial Orthop. 2007; 131(2): 253-62.

23. Sims MR. Brackets, epitopes and flash memory cards: A futuristic view ofclinical orthodontics. Aust Orthod J. 1999; 15(5): 260-8.



Evolution of Orthodontic Brackets

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