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Objective: evaluation of friction forces between Damon bracket and conventional bracket considering invitro studies of literature.Materials and methods: evaluation of thirteen in vitro studies of literature from 1998 to 2016.Results: the production of low friction by self- ligating bracket depends to diameter of archwire and so isobtained easily with round archwire and another factor that influences the friction is the bracket design.
Sliding a tooth along an archwire is a very common orthodontic procedure to translate tooth, but one ofthe disadvantages of this system is the frictional forces between wire and brackets. These forces can resultin decreased treatment efficiency, loss of anchorage and , consequently, unwanted tooth movement. Twomajor types of friction can be defined: static friction which is the resistance that prevents initial movementstooth and kinetic friction which is the force required to resist the sliding motion of one solid object overanother at constant speed (1).The nature of friction in orthodontics is multifactorial, which is derived from both mechanical and biologicalfactors; mechanical factors such as archwire properties , method of ligation and bracket properties;biological factors such a as saliva, plaque, corrosion and food particles (2).The method of ligation have a central role in the making of friction forces , therefore various method havebeen proposed to reduce these forces such as self-ligating bracket. SLBs are ligatureless bracket systemsthat have a mechanical device which is built into the bracket to close off the slot. There are two types ofself-ligating bracket: active SLB, that have a spring clip that presses against the archwire and passive SL inwhich the self-ligating clip does not press against the wire. The Damon 3 SLB is a passive self- ligatingbracket and use covers that slide vertically in an occlusal direction. The slot size of this brackets is0.022x0.027 inch.(1).Nowadays, self-ligating brackets have become very popular in orthodontics practice and both patients andorthodontist are more interested in using them.The aim of this review is the evaluation of the studies that compare the friction forces in Damon 3 bracketsand conventional bracket system.
It was realized a search on Pubmed of in vitro studies from 1998 to 2016 using key word like "Damonbracket", "self-ligating bracket" and "low friction in orthodontic". Have been selected thirteen articleswhich are compared self-ligating bracket and conventional bracket.
By the result of the studies analyzed, in literature there are two groups of studies based on the resistanceforces to sliding and static friction in Damon and conventional brackets. One group reported no significantdifferences between self-ligating and conventional brackets (1-8- 9-11- 12-13), while the other group (2-3 - 7-10- 14-15- 16-) claimed that self -ligating brackets produce less friction than conventional ones with asignificant difference. These differences depends on the type of wire used; Pandis et al. (8 )mentionedthere was no difference in frictional forces between SLB and conventional brackets because they usedrectangular archwire that fill the slot of Damon bracket and produce more friction; Kumar et al.(6) haveshown that friction appears to increase as archwire diameter increases, also with Damon bracket, in factwith all the bracket type the 0.019x0.025 inch. steel stainless wire produces the highest friction, even ifDamon 3 passive SL system showed the lowest friction for all dimension of test wire compared to the othertype of bracket tested. The group of studies that claimed the less friction of self- ligating brackets are basedon the use of a round archwire that canât contact all the surface of the slot and consequently less frictionarise. Tecco et al.(7) have shown that Damon 3 produced less friction with a round wire and that time 3,SLB active produced more friction; these differences observed among the SLB could be explained by thedifferences in the shapes of their little caps that can or not press the wire against the slot and increase thefriction. So two important factors affect the arise of friction forces: diameter of wire, bracket design (5).The presence of a flared slot allows better guidance of the wire at the bracket corner, like says Crincoli et al.(3), this slot design reduce the binding and notching of the wire against the corner of the bracket. Whenthe corner of contact between bracket and archwire is wide, the sliding movement of teeth can bedisturbed by vertical forces produced at both ends of the bracket slot as the bracket archwire angulationincreases and causes binding. Under high magnification of an electron microscope the corners of Damonbrackets slot showed smooth surfaces and so that reduce the friction (4).
Reduction of frictional forces during sliding mechanics increases the efficiency of the orthodontictreatment, but the choice of bracket system may consider the phase of treatment. SLB system is moreefficient in the alignment phase (6) because produced low friction compared to conventional bracket,where the ligature contact the wire and make high friction.
1. Mohammad Karim Soltani, Farzaneh Golfeshan Yoones Alizadeh, Jabraiel Mehrzad. Resistance ToSliding In Clear And Metallic Damon 3 And Conventional Edgewise Brackets: An In Vitro Study. JDent Shiraz Univ Med Sci., 2015 March; 16(1 Suppl): 15-202. Sujeet Kumar, Shamsher Singh, Rani Hamsa.P.R , Sameer Ahmed, Prasanthma, Apoorva Bhatnagar,Manreet Sidhu, Pramod Shetty. Evaluation of friction in orthodontics using various brackets andarchwire combinations-an in vitro study. Journal of Clinical and Diagnostic Research. 2014, May,Vol 8(5): ZC33-ZC36.3. Vito Crincoli, Letizia Perillo, Maria Beatrice Di Bisceglie, Antonio Balsamo, Vitaliano Serpico,Francesco Chiatante, Carmine Pappalettere E Antonio Boccaccio. Friction Forces During Sliding OfVarious Brackets For Malaligned Teeth: An In A Vitro Study. The Scientific World Journal Volume2013, Article ID 871423.4. Souk Min Lee, Chun-Ju Hwang. A comparative study of frictional force in self-ligating bracketsaccording to the bracket-archwire angulation, bracket material, and wire type. Korean J Orthod2015;45(1):13-19.5. Riccardo Nucera, Antonino Lo Giudice, Giovanni Matarese, Alessandro Artemisia, Ennio Bramanti,Paolo Crupi, Giancarlo Cordasco. Analtsis of the caracteristics of slot design affecting resistance tosliding during active archwire configurations. Progress in Orthodontics 2013, 14:35. 6. Vijaya Bhaskara Reddy, Talapaneni Ashok Kumar, Mandava Prasad, Sivakumar Nuvvula, RajedraGoud Patil, Praveen Kumar Reddy. A Comparative In-Vivo Evaluation Of The Alignment EfficiencyOf 5 Ligation Methods: A Prospective Randomized Clinical Trial. European Journal of Dentistry, vol8/issue 1/ Jan-Mar 2014.7. Simona Tecco, Donato Di Iorio, Riccardo Nucera, Beatrice Di Bisceglie, Giancarlo Cordasco, FeliceFesta. Evaluation of The Friction of Self-Ligating and Conventional Bracket Systems. Eur J Dent2011;5:310-317.8. Pandis N, Polychronopoulou A, Eliades T. Self-ligating vs conventional brackets in the treatment ofmandibular crowding: a prospective clinical trial of treatment duration and dental effects. Am JOrthod Dentofacial Orthop 2007; 132: 208-215.9. Vanessa Vieira Leite, Murilo Baena Lopes, Alcides Gonini Junior, Marcio Rodrigues De Almeida,Sandra Kisss Moura, Renato Rodrigues De Almeida. Comparison of frictional resistance betweenself-ligating and conventional brackets tied with elastomeric and metal ligature in orthodonticarchwires. Dental Press J Orthod.2014 May-June; 19(3):114-9.10. Maria Regina Guerra Monteiro, Licinio Esmeraldo Da Silva, Carlos Nelson Elias, Oswaldo DeVasconcellos Vilella. Frictional resistance of self-ligating versus conventional brackets in differentbracket-archwire- angle combinations. J Appl Oral Sci. 2014; 22(3):228-34.11. Krishnan M, Kalathil S, Abraham KM. Comparative evaluation of frictional forces in active andpassive self-ligating brackets with various archwire alloys. Am J Orthod Dentofacial Orthop 2009;136: 675-682.12. Scott P, DiBiase AT, Sherriff M, Cobourne MT. Alignment efficiency of Damon3 self-ligating andconventional orthodontic bracket systems: a randomized clinical trial. Am J Orthod DentofacialOrthop 2008; 134: 470.13. Ehsani S, Mandich MA, El-Bialy TH, Flores-Mir C. Frictional resistance in self-ligating orthodonticbrackets and conventionally ligated brackets. A systematic review. Angle Orthod 2009; 79: 592-601.14. Pizzoni L, Ravnholt G, Melsen B. Frictional forces related to self-ligating brackets. Eur J Orthod 1998;20: 283-291.15. Thomas S, Sherriff M, Birnie D. A comparative in vitro study of the frictional characteristics of twotypes of self-ligating brackets and two types of pre-adjusted edgewise brackets tied withelastomeric ligatures. Eur J Orthod 1998; 20: 589-596.16. Henao SP, Kusy RP. Evaluation of the frictional resistance of conventional and self-ligating bracketdesigns using standardized archwires and dental typodonts. Angle Orthod 2004; 74: 202-211.