Most people feel that elastomerics result in more plaque accumulation then wire ligatures
There are some studies that support this
Forsberg et al. Ligature wires and elastomeric rings: two methods of ligation, and their association with microbial colonization of Streptococcus mutans and lactobacilli. 1991. Eur J Orthod. 13:416-420.
There are other studies that found no difference
Sukotapatipark et al. A scanning electron microscopy study. 2001. Eur J Orthod. 23:475-484. 2001.
Extended range of activation due to energy stored in clip
Large interbracket span
Spring clip will not deform or fatigue
Horizontal auxiliary slot
Treatment Philosophy - As outlined by Dr. Hanson
Try to treat without extractions in any case that has the necessary potential
If extractions necessary, extract 2nd bicuspids to minimize any reduction in prominence of dentition
Preliminary functional appliances as necessary to favorably alter jaw growth if possible
Use intraoral distalization instead of headgear
Expand arches that have failed to develop to their full potential
In patients that exhibit lots of gingival tissue, intrude upper anterior teeth
Correct tooth rotations to ideal alignment without overcorrection - rely on IPR and circumferential supra-crestal fiberotomies to enhance retention
Overcorrect Class II/III where strong tendency for relapse occurs
SPEED pictures The SPEED finishing archwire has a quarter round shape, which facilitates archwire insertion, spring closure, and is highly effective in torque control. Supercable consists of seven strands of superelastic nickel titanium wire in a coaxial form. It is impossible to permanently deform Supercable regardless of the malalignment of the dentition. (B) The combined effect of the initial light multistrand Supercable archwire, the wide interbracket span between the narrow SPEED brackets, and the energy storing capability of the spring clip greatly increases the range of appliance activation.
Many authors (Thomas et al. 1998 Eur J Orthod, Pizzoni et al. 1998 Eur J Orthod, Khambay et al. 2004 Eur J Orthod) have found that static friction measured in vitro is much less with a passive self ligating appliance that any other type of fixed appliance
When angulation or inclination is applied to the bracket friction is generated, however it is less for SLB’s than for conventional ligation
Figure showing static friction for passive, active, TipEdge, and conventionally ligated brackets. The value for the passive self-ligating Damon SL bracket was zero except for with the 0.019″ × 0.025″ stainless steel archwire. The wires were drawn through the brackets and the frictional resistance was measured using an Instron 1193 testing machine.
Active Clips - SPEED, In-Ovation, Quick Brackets, Time2 (American ortho)
Passive - Damon, Smart clip, Praxis Glide, and Carriere LX
Intended benefit of storing some force in the clip - “a given wire will have its range of labiolingual action extended and produce more alignment than would a passive slide with the same dimension wire”
However, with increased clearance between a given wire and a passive slide, lower forces will be generated along with less binding to possibly allow teeth to push each other as they slide along the wire
Not many studies have been done to assess the effectiveness of active versus self ligation at this point
Purpose of the study was to measure the difference in 3rd order moments that can be delivered by engaging a 19x25 SS AW to various brackets
2 Active SLBs were used - In-Ovation and SPEED
2 Passive SLBs were used - Damon2 and Smart Clip
A bracket/wire assembly torsion device was used - is able to apply torsion to a wire while maintaining perfect vertical and horizontal alignment between the wire and the bracket
The torque was then measured by a multi-axis force/torque transducer
Results showed that torque started to be expressed at lower degrees of torsion (7.5) for the active SLBs versus the passive SLBs (15)
Concluded that active SLBs are more effective in torque expression
External apical root resorption in patients with conventional and self-ligating brackets
Aim was to investigate the amount of external apical root resorption between conventional and passive SLBs (Damon2)
96 patients selected
Pts received Tx with either SLBs or conventional brackets with .022 slot
No difference was found in the amount of EARR, but a positive association existed between EARR and duration of TX
Alignment efficiency of Damon3 self-ligating and conventional orthodontic bracket system: A randomized clinical trial
Aim of this study was to compare the efficiency of mandibular tooth alignment and the clinical effectiveness of a self-ligating (Damon 3) and a conventional preadjusted orthodontic bracket (Ormco bracket).
62 pts from 2 orthodontic clinics (32 male, 30 female) with mandibular incisor irregularities (Little’s Irregularity Index) of 5 to 12mm and prescribed extraction pattern including the mandibular first premolars
Wire sequence: .014 NiTi 14x25 Niti 18x25 NiTi 19x25SS
No difference in the initial or the overall rate of mandibular incisor alignment between the two bracket types
Only significant influence of initial rate of alignment was the amount of initial irregularity
Sadowsky, PL. Self-Ligating Orthodontic Brackets. 2008. Seminars in Orthodontics. 14(1).
Scott P, DiBiase A, Sherriff M, Cobourne M. Alignment efficiency of Damon3 self-ligating and conventional orthodontic bracket systems: A randomized clinical trial. 2008. Am J Orthod Dentofacial Orthop. 134:470.e1-470.e8.
Pandis N, Nasika M, Polychronopoulou A, Eliades T. External apical root resorption in patients treated with conventional and self-ligating brackets. 2008. Am J Ortho Dentofacial Orthop. 134:646-51.
Matarese G, Nucera R, Militi A, Mazza M, Portelli M, Festa F, Cordasco G. Evaluation of frictional forces during dental alignment: An experimental model with 3 nonleveled brackets. 2008. Am J Ortho Dentofacial Orthop. 133:708-15.
Badawi H, Toogood R, Carey J, Heo G, Major P. Torque expression of self-ligating brackets. 2008. Am J Orthod Dentofacial Orthop. 133-721-8
Rinchuse D, Miles P. Self-ligating Brackets: Present and Future. 2007. Am J Orthod Dentofacial Orthop. 132:216-22
Thomas S, Birnie DJ, Sherriff M. A comparative in vitro study of the fricitonal characterisitics of two types of self-ligating brackets and two types of preadjusted brackets tied with elastomeric ligatures. 1998. Eur J Orthod 20:589-596.
Srinivas S. Comparison of canine retraction with self-ligated and conventional ligated brackets—a clinical study. 2003. Thesis in fulfillment of postgraduate degree, Tamilnadu Medical University, Chennai, India