1.Self Ligating Brackets Past Present Future of Orthodontics

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JOURNAL OF DENTAL SCIENCES Volume 2 Issue 1 SELF-LIGATING BRACKETS : PAST, PRESENT & FUTURE OF ORTHODONTICS Dr. Aakash Shah Abstract : Self-ligating brackets have been gaining popularity over the past several decades. The purpose of this article is to search previous orthodontic literatures and databases with regard to the efficiency, effectiveness & stability of treatment with selfligating brackets. Keywords - Self-ligating bracket, friction, robust-ligation. Introduction : A self -ligating b
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  4 JOURNAL OF DENTAL SCIENCES  Volume 2 Issue 1 SELF-LIGATING BRACKETS :PAST, PRESENT & FUTURE OF ORTHODONTICS Address for Correspondence : Dr. Aakash ShahDept. of Orthodontics & Dentofacial OrthopaedicsFaculty of Dental Science, Dharmsinh Desai University,NADIAD - 387 001. GUJARATPHONE:079-27681666 E-MAIL: drabs@live.com Dr. Aakash Shah Dept. of Orthodontics & Dentofacial OrthopaedicsFaculty of Dental Science, Dharmsinh Desai University,NADIAD - 387 001. GUJARAT Professor  Introduction :  A self -ligating bracket is a ligature less system with amechanical device built-in to close-off the bracket slot.Secure engagement of the main archwire into bracketmay be produced by a clip mechanism replacing thestainless steel or elastomeric ligature.Both active and passive self-ligating brackets have beendeveloped depending upon the bracket & archwireinteraction. The active type has a spring clip that pressesagainst the arch wire (In ovation R*, or Speed**). In thepassive type, the clip or rigid door does not actively pressagainst the arch wire (Smartclip***, Damon 3MX****). History of Self-ligating Appliances : st The concept of self-ligating brackets was 1 described in 1 1935 with the Russell- Lock edgewise attachment. At thattime, operator efficiency was the main advantageadvocated. A dramatic peak in the popularity of self-ligation occurred in the 1990’s; by than many refinements inself- ligating systems had arrived and also madepatented. Recent products include Smartclip 3, In ovationC and Damon 3MX. Illustration 2 – Self ligating ceramic brackets Table-1History of Self Ligating SystemSystemYear Introduced Russell Lock1935 2 Edgelok (Ormco)1972Mobil Lock (Forestadent)1980 3 Speed (Strite Industries)1980 4  Activa (“A” Company)1986Time (Adenta)1994 5 Damon SL (“A” Company)1996Twinlock (Ormco)1998Damon 2 (“A” Company/Ormco)2000In Ovation (GAC)2000In Ovation R (GAC)2002Philippe (Forestadent)2002Smartclip (3M Unitek)2004Sure (Denrum)2005Quick (Forestadent)2005Damon 3MX (Ormco)2006Smartclip 2 (3M Unitek)2006In Ovation C (GAC)2006Clarity SL (3M Unitek)2007 10 Smartclip 3 (3M Unitek)2009 Abstract : Self-ligating brackets have been gaining popularity over the past several decades. The purpose of this article is to searchprevious orthodontic literatures and databases with regard to the efficiency, effectiveness & stability of treatment with self-ligating brackets. Keywords - Self-ligating bracket, friction, robust-ligation.Illustration 1 – Conventional ceramic bracket with elastomeric ligature ties. **********Trademark of GAC InternationalTrademark of Strite Industries Ltd.Trademark of 3M UnitekTrademark of Ormco/”A” Company  5 JOURNAL OF DENTAL SCIENCES  Volume 2 Issue 1Advantages of Self-ligating Preadjusted EdgewiseSystem : 1)Secure & robust ligation2)Reduced friction3)Enhanced efficiency & ease of use4)Reduced overall treatment time5)Efficient alignment of severely irregular teeth.6)Better plaque control & anchorage conservation7)Reduced risk of operator & patient injury including“Puncture Wounds”.Following potential advantages were further searched inthe literatures :- (i)Secure, robust ligation and fully bracketengagement :- The shortcomings of elastomeric materials are well known. 6 Taloumis and Colleagues, in an invitro study, demonstratedhigh decay rates of elastomeric forces within 24 hours.Dowling & Colleague’s study showed a similar reduction instrength of elastomeric modules.Degradation of elastomeric ligature ties has been found tocause a significant loss of full bracket engagement. A figure-8 elastic ligature tie seems to make arch wire ligation moresecure, but this improvement comes at the expense of increased frictional resistance, which may be on the order of 70-220%.Full, robust arch wire engagement is assured in self -ligatingsystem unless the clip or slide mechanism fails. There is noproblem of decay of the ligature as with elastic ligatures. Table-2Friction in different type of brackets STUDYHIGHEST FRICTIONINTERMEDIATE FRICTIONLOWEST FRICTION Table-3Reduced chairtime required for archwire removal & insertionwithself-ligating appliances as compared to conventional appliances. 8 Maijer& SmithSPEEDElastomerics7 minutesShivapuja & BergerActiva, EdgelokWire ligatures12 minutesSPEEDVoudourisInteractwinElastomerics2.5 minutesBerger & ByloffSPEEDElastomerics2-3 minutesTurnbull & BirnieDamon 2Elastomerics1.5 minutes STUDYSELF LIGATING SYSTEMCONVENTIONALMODE OF LIGATIONTIME SAVINGS However, 50% patients have reported slide mechanismbreakages in cases where Damon SL brackets were used.But introduction of newer systems like clip mechanismhas virtually eliminated such problems. (ii)Reduced Friction :- Very low friction with self ligating brackets has been clearlydemonstrated and quantified in work by various authors. 9 Bednar & Colleagues showed that elastomerics introducedmore friction into the appliance system than stainless steel 7 ligatures. Shivapuja & Berger confirmed this finding,reporting that wire ligating produced only 30-50% of thefrictional forces as compared to elastomerics. Meling &Colleagues came to similar conclusions. The passive self-ligating appliances (Damon, Smartclip) typically havelower friction than the active systems. (In Ovation R,Speed). A reduced friction appliance produces more rapid, efficientalignment, rotational corrections and space closure andthus it is also very less taxing on the anchorage. (iii)Efficiency & Ease of use :- Self- ligation system results in a consistent reduction inchairtime for fixed appliance adjustment compared toconventional appliances.In SHIVAPUJA & BERGER study, the use of wireligatures added almost 12 minutes to the time needed toremove & replace two arch wires. The time saved in self-ligating system (chairside) could be used to schedule morepatients, increase efficiency, improve patient relations, or allow oral hygiene reinforcement.  6 JOURNAL OF DENTAL SCIENCES  Volume 2 Issue 1 (iv)Reduced overall treatment time :- A study of treatment efficiency by self-ligating brackets byHarradine found the following :ãA mean reduction of four months in treatment time.ãA mean reduction of four visits during activetreatment.D. Robust Fry in a presentation at the AAO Annual Session inToronto 2001 reported similar 4 months reduction intreatment times. A study by Eberting et al found an average reduction intreatment time of 7 months and 7 visits for self-ligatingbrackets compared to conventional ligation.These reports suggest a clinically significant improvement intreatment efficiency with self-ligating brackets.(v)More efficient alignment :-Miles compared the alignment efficiency of self-ligatingbrackets and conventional twin brackets in two studies.In his first study, he noted that 0.7 mm more irregularityremained after initial alignment in the group treated with self-ligating (Smartclip) appliance than in a group treated withconventional twin bracket; this he attributed to therotational play of 6.8” allowed by the passive self-ligatingsystem.In a second study, which was a split mouth studydesign, Miles and Colleagues found that twin bracket hadachieved an irregularity index 0.2 mm less than that of self-ligating brackets (Damon 2 brackets). Again, this wasattributed to the initial 0.014” nickel titanium, with thepotential for greater rotational play.These findings suggest that any time savings arisingfrom the use of self-ligating brackets do not occur in theinitial alignment phase of treatment. (vi)Improved Patient Comfort :- Wire ligatures require careful tucking in of the ends to avoidsoft tissue trauma, and can occasionally be displacedbetween appointments and cause discomfort. In self-ligating brackets, there is no chance of poking into patient’ssoft tissue as there is no ligation. Torque Expression :- The influence of bracket type on torque expression in theupper segment has been assessed in a randomizedcontrolled trial. The Damon 2 appliance was found to beequally capable of torque delivery, relative to the SN &NA lines, compared to a conventional bracket system.Little difference in mandibular incisor inclination changewas reported in a prospective clinical trial of Smartclip &conventional brackets. Incisor proclination of 4.410 and4.320 occurred in the respective groups during archleveling & alignment; incisor production was governedlargely by the initial incisor inclination and the degree of crowding resolved during the study period. An active self-ligating appliance that presses the wire into the base of thebracket may facilitate more effective torque expression withundersize archwires than can be achieved with a passiveself-ligating system. u ãfailure to provide and to maintain full archwireengagement results in poor control of tooth movement.ãfrictional values are increasedãfor elastomerics, the force decays and therefore toothcontrol is not optimal.ãBoth wire and elastomeric ligatures sometime becomedisplaced.ãOral hygiene is potentially impeded.ãWire ligation is a time-consuming clinical procedure.Self ligation offers significant improvements relative to all of these factors. u Feature of self-ligatiing brackets available in Market.(A)Speed brackets : Speed brackets (Strite Industries Ltd., 298 Shepherd Avenue, Cambridge, Ohtario, N3C IVI Canada, Illustration -3) have remained in successful production since 1980.Earlier brackets had clips which could too easily be displacedor distorted . These drawbacks have been taken care of.These brackets doesn’t have the familiar tie-wings Illustration 3 – Speed bracket  (B)Activa brackets :  Activa brackets (“A Company, San Diego, CA, Illustration- 4) had a rotating slide, which therefore gave a concave inner radiaus to the labial surface of the slot. These increased slotdepth reduced the labiolingual alignment efficiency. Thebracket is wider than the average bracket, which reduced theinter-bracket span with the consequent disadvantages. Tie-wings were absent and a different bonding base madebracket positioning more difficult. Illustration 4 – Active bracket  Limitations of Conventional Ligation  7 JOURNAL OF DENTAL SCIENCES  Volume 2 Issue 1(C)Time 2 bracket : The time 2 bracket (Adenta Gmbh, Illustration - 5) has aclip that rotates into position around the gingival tie wing androtates towards the occlusal rather then the gingival wall of the slot. Illustration 5 – Time 2 bracket  (D) DAMON SL Brackets : Damon SL brackets (“A Company, San Diego, CA,Illustration - 6) had a slide that wrapped around the labialface of the bracket. Launch of Damon brackets in mid 1990smade a definite step forward in popularity of self-ligatingbracket. Damon SL brackets had two significant problems—the slides sometimes opened inadvertently and they wereprone to breakage. Illustration 6 – Damon SL bracket  (E) DAMON 2 Brackets : Damon 2 brackets (Ormco Corp. Illustration - 7) wereintroduced to address the imperfections of Damon SL.Combined with the introduction of metal injection moldingmanufacture & slight design changes, Damon 2 bracketsare almost completely free from inadvertent slide openingor slide breakage. However, the brackets were notimmediately and consistently very easy to open. Illustration 7 – Damon 2 bracket  (F) DAMON 3 and DAMON 3MX Brackets : Damon 3 and Damon 3MX brackets (Ormco corp.Illustration - 8) have a different location and action of theretaining spring, and this has produced a very easy andsecure mechanism for opening and closing. In addition,Damon 3 brackets are semi-esthetic. However, earlyproduction of Damon 3 brackets suffered three significantproblems : a high rate of bond failure, separation of metalfrom reinforced resin components, and fractured tie wings.These three problems received rapid and effectiveinvestigation and correction. Damon 3MX bracket is a allmetal bracket with least problems Illustration 8 – Damon 3 and Damon 3MX brackets (G)SYSTEM R Brackets : System R brackets (GAC International Inc. 355kniterboker Ave. Bohemina, NY11716, Illustration - 9)srcinally called In-ovation brackets, are very similar to thespeed brackets in conception and design, but of a twinconfiguration with tie wings. In 2002, smaller brackets for thelower anterior teeth became available. In-Ovation R(Reduce, referring to the reduced brackets width) and thisnarrower width was effective in terms of greater inter bracket span. The bracket subsequently became known assystem R. Some brackets of this type are difficult to openand this is more common in the lower arch where thegingival end of the spring clip is difficult to visualize. Excesscomposite at the gingival aspect of brackets in the lower archcan be difficult to see and may also hinder opening. Similarly,lace backs, under ties and elastemerics placed behind thearch-wire are competing for space with the bracket clip. BothSpeed and System R and also the similar and recentlyreleased Quick brackets (forestadent Bernhard Foerster Gmbh, fig. 8) have addressed this difficulty by providing alabial hole or notch in the clip in which a probe or similar instrument can be inserted to open the brackets Illustration 9 – System R brackets
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