BY RON RONCONE, DDS, MS
Although self-ligating brackets (SLBs) have been around for many years, they have only recently been in the spotlight. Modern self-ligation first occurred with the Edgelock® bracket, introduced by Ormco™ in the 1970s. It was big, difficult to open, and was welded to a band. In the early 1980s, Orec produced the Speed bracket, developed by Dr Herbert Hanson. It was, and is, a very aesthetic metal bracket. However, its small mesio-distal width makes it difficult to place precisely, and corrections of rotations are a problem.
Other SLB brackets came to market, and several of them hit big time. These include the Damon® bracket in several forms, and the In-Ovation brackets. Various companies produced their versions of “passive” and “interactive” brackets (more on that later): Forestadent® (BioQuick® and QuicKlear®), 3M™ Unitek™ (SmartClip™), and American Orthodontics (Empower®) being the most noteworthy.
So what is it about these brackets that provoke controversy? Are SLBs, in general, any better than traditional twin brackets? Are there any differences between “passive,” “active,” and “interactive”? Which is better, if any?
The great thing about orthodontics is that we can all have our opinions and treat with different brackets and different mechanics. So, what follows is the opinion of one orthodontist based on the use of many traditional, and most SLBs.
To get started, let’s look at the claims made about SLBs:
- Treat patients more quickly.
- Allow longer intervals be-tween patient appointments.
- Allow fewer patient visits.
- Treat patients to a better result.
- Eliminate the need for ex-pansion appliances.
- The reduction in friction causes teeth to move faster.
It is my opinion, based on the last 25 years of practice, that all of these claims are FALSE!
Traditional Twin Versus Self-Ligating Brackets
I have used heat-activated Niti (HANT) and superelastic wires in my practice since 1988. These patients were allowed to go 8 to 12 weeks in-between appointments. The reason this was possible was that the wires were fully ligated into the slot using steel ligatures—NOT elastic modules (Figures 1 and 2).
Elastic modules do not maintain proper force levels and need to be changed every 3 to 5 weeks. Therefore, more appointments are necessary. SLBs contain the HANT wires, and therefore appointments can be extended. If ligated properly, the appointment intervals between twin and SLBs are identical. On average, comparing total treatment time for 2,500 traditional and 2,500 SLB patients, SLBs treated faster by only 3 weeks.
Passive, Active, and Interactive Brackets
Some clinicians have postulated that light-force, small-diameter HANT wires produce less friction and therefore faster tooth movement. This has NOT been my experience. In fact, large-diameter, light-to-medium-force wires (with more friction) produce faster, more directional forces. In case after case, friction has been and continues to be helpful not only for finishing and torque but also in the initial stages of leveling, rotation correction, aligning, and Curve of Spee correction. Therefore, my appliance of choice is an interactive SLB.
Interactive SLBs, when used with appropriate-diameter HANT wires, afford more control and provide directional tooth movement toward the final goal. Additionally, the use of only titanium archwires provides a more physiologic sequence of treatment and has virtually eliminated root absorption.
If SLBs and traditional twin brackets are similar in treatment time and number of appointments, why choose the SLB—especially since they are more costly? There are several reasons for this choice:
- Traditional twin brackets, when tied with ligature wire, take much longer to “tie-in”—longer appointments.
- Traditional twin brackets are more difficult to keep clean with steel ligatures.
- If one is careful, wire pokes should not be a problem, but somehow the ligatures cause more problems.
- Patients for many years have told us that they want aesthetic orthodontics, so I use clear SLBs routinely. Some may counter that there are clear (ceramic, etc) twin brackets that are aesthetic. However, the method of ligation is not aesthetic. The choices are coated ligature wires, which “stand out” and eventually lose the white coating, or clear elastic modules, which yellow within a few weeks.
- From a marketing standpoint, it is easy to inform patients that they will not have to come in for “tightenings.” The wires and SLBs “tighten” automatically.
If orthodontists are to satisfy the patients’ need for aesthetics, convenience, a minimal number of appointments, gentleness, and speed of treatment, systems are necessary to routinely achieve these goals. I have named this system The PhysioDynamicSystem (PDS). This consists of six general steps, which are followed sequentially:
- Relaxation of all muscles of the head and neck
- Then, proper diagnosis of orthodontic problems
- Use of The Roncone PDS Bracket Prescription
- Individualized Ideal bracket placement using J.S.O.P.® (Just Short Of Perfect) Jigs
- Correct implementation of Three Stages of Treatment using The PDS Archform
- Aesthetic, functional post-removal finish
For purposes of this discussion, let’s concentrate on the bracket system and sequence of wires routinely used. The SLBs of choice are:
- BioQuick metal SLB
- QuicKlear ceramic SLB
Brackets of Choice
Forestadent manufactures the brackets used in the Roncone PD System of orthodontics.
1. BioQuick—Metal, Inter-active, Self-Ligation
This bracket has significant advantages over other metal SLBs. It is one piece with an undercut base, which stays bonded. Because of this unique base, most of the bonding material comes off the tooth on debonding. The profile is smaller, and the clip is very sturdy. If a clip should fail, it can easily be replaced. Opening and closing the clip can readily be accomplished with several instruments.
2. QuicKlear—Ceramic, Inter-active, Self-Ligation
All of the above advantages are true for this bracket in addition to superb aesthetics and the ability to easily and painlessly remove the bracket and reuse it when placement issues are a problem.
Correct Implementation of the Three Stages of Treatment
For 90% of patients, there are three stages of treatment.
Stage 1: Uses round heat-activated and/or superelastic PDS wires. These round wires are kept in place for a minimum of 6 months. The force and diameter of these wires are critical.
a) Mild to moderate crowding requires an .018 PDS HANT wire.
b) Moderate to severe crowding requires (two) .014 superelastic wires placed in the slot (.022 x .028) together. These wires are not changed until Stage 2 wires are placed.
Stage 2: Uses a .020 x .020 PDS HANT wire as a quality control. This allows the orthodontist to check on precise bracket placement and is in the mouth for 6 weeks. If brackets need to be changed, the same wire is replaced for another 6 weeks. If not, Stage 3 wires can be placed.
Stage 3: Uses PDS Beta Titanium wires in the upper and lower arches. The upper is an “L” loop wire distal to maxillary laterals. The lower is an Ideal wire.
In the PD System of orthodontics, there is only one archform. Archform is not about faces; it is about function!
Case Example: Class II, Division 1 subdivision, significant lower crowding, moderate overjet
The Class II shown above was corrected using the .020 x .020 PDS molar tube. The combination of rotation in Stage 1, anchorage with the torque and rotation in Stage 2, and 3 months of short Class II elastics on the right side to “sock-in” posterior teeth in Stage 3, corrected the problem in 13 months and six appointments. Of course, approximately 8% to 12% of patients do not fall neatly into any system. Those cases require more wires and bends, and take longer. However, when 90% of malocclusions can readily be treated with two to three wires and in a short amount of time, it can be a significant bonus. OP
RON RONCONE, DDS, MS, received his undergraduate degree from Marquette University. He pursued graduate study in muscle physiology and neuroanatomy at the Medical College of Wisconsin while simultaneously earning his dental degree from Marquette University School of Dentistry. He earned two postdoctoral certificates in orthodontics from Harvard School of Dental Medicine and Forsyth Dental Center. He has taught orthodontics at Harvard and the University of Maryland. He has presented more than 1,000 lectures in all 50 states and 43 countries.