Q&A: Self-Ligating Brackets by Dr. Daniel Grob

A discussion of the pros, cons and specifics

by Orthotown Editorial Director Dr. Daniel Grob

With the rapid change in orthodontic delivery systems and appliances—hello, clear aligner therapy!—some clinicians may feel like the days of brackets and wire are over, or soon to be completely replaced. But judging from the discussion I recently had with experienced clinician Dr. Stuart Frost (pictured), that’s anything but the case.

After a recent conversation about self-ligating brackets, I came away more enthusiastic than ever about the future of traditional appliances with modern technological advances. Included in the talk: the design and advantages of passive versus active self-ligation; the specific benefits to patient care; whether treatment times really become shorter; and patient comfort.

As an early adopter of Damon technology and philosophy—and the author of The Artist Orthodontist: Creating an Artistic Smile Is More Than Just Straightening Teeth—Frost is supremely qualified to introduce many topics for consideration as you choose your method for treatment.

What prompted you to get involved with self-ligating brackets? Do you still use other types of brackets—and if so, how do you decide which works best?

Dr. Stuart Frost: When I worked as a general dentist in my father’s practice, I noticed some things that concerned me in patients who came back from their orthodontists. More than half of them were getting four bicuspids extracted, and I was asked to extract upper bicuspids on my own brother-in-law, who was 12 at the time. I will never forget the day I pulled those upper bicuspids on him: I remember thinking how I wished I didn’t have to do that.

There were other things, as well—I noticed quite a bit of root shortening, gingival stripping and bone loss with the cases that were being treated. Many of these patients had been in treatment for five or more years.

When I started my orthodontic residency, Dr. Paul Damon was in the class ahead of me and one day he mentioned that his father was going to speak to the orthodontic residents and faculty about his new bracket system. I showed up on that Saturday in 1997 and sat in the front row of the auditorium. As I listened to Dr. Dwight Damon speak, he mentioned that this passive self-ligation bracket would create beautiful smiles with fewer extractions, faster treatment times, and less headgear and expanders. I remember him saying that the tissues would be better and there’d be less root shortening. This spoke to me because I recalled what I saw in my years as a general dentist.

After seeing Damon’s cases, which were beautiful and unlike any other case finishes I had ever seen, I knew that I was going to use passive self-ligation in private practice. I opened my practice from scratch in 2000 with the Damon system as my bracket system, and have used it ever since.  

There are two types of self-ligating brackets—active and passive self-ligating. What’s the difference, and which do you prefer?

The differences between passive and active self-ligating brackets is small, but I’ve found that there’s a big difference during treatment and in the outcomes they produce.

“Passive” means that there is a door that slides over the slot, creating a tube in which the wire sits throughout all phases of wire sequencing and treatment. The wire is passive in the slot, meaning that it can move freely and has play in all dimensions until a full wire is introduced and a torque is coupled. This creates a low-friction environment, allowing the tooth to move more efficiently, and with less friction and binding between the bracket and wire.

Active self-ligation has a clip that closes over the slot, rather than a door that slides over it. Although both systems act similarly in the beginning stages of treatment, active self-ligating brackets introduce friction and binding once the patient reaches rectangular wires. In my opinion, this creates a disadvantage for the active-clip cases, because early in treatment binding in the brackets introduces binding between the wire and the bracket.

One advantage that active-clip users claim is early torque control in the anterior, but the posterior binding isn’t talked about much. If the goal in both systems is taking anterior crowding and developing it into posterior arch width, then remaining passive throughout all phases of treatment has an advantage in the broadening of the arches and less trauma on the roots and tissue. With passive self-ligation, torque is increased gradually as the wires’ size increases and a coupling occurs. My goal in treatment is to stay as passive as possible, which allows for play in the bracket slot, the best settling of the occlusion and the broadest arches without binding and friction.

We often hear that self-ligating brackets have certain advantages—faster finishing, for example. How have you seen this play out in your clinical practice? 

I think the biggest advantages we see for self-ligating brackets—and specifically passive self-ligating brackets—appear in the beginning stages of treatment, especially in cases that have moderate to severe crowding. Because there is less friction and binding, I’ve been able to solve anterior crowding issues without extracting teeth by creating transverse arch width.

I’ve seen this create a three- to four-month advantage over using twin brackets to solve the same issues. By saving time in the initial stages, it can make up time in finishing. With passive self-ligation (PSL), I’m able to see the patients every 10 weeks, which allows me to be more efficient in practice (and patients appreciate not having to come to the orthodontist every four to six weeks, which is the norm with standard bracket systems. I’ve also found that I finish anywhere from four to six months earlier than the national averages of finishing with twin brackets.

How do clinicians know if they are maximizing the bracket? What sort of learning curve is involved?

The key to using a passive self-ligating bracket is to treat it less like a bracket and more like a system. Unfortunately, many doctors try to use a PSL bracket using twin-bracket mechanics and run into problems. I’d say there is a steep learning curve in the beginning, because the way you use a PSL bracket is very different from what’s taught in school on how to treat with a twin bracket.

The other learning curve is training your team members on how this new technology works—how differently they engage the wires and brackets, and how this relates to the patient treatment. For example, for the system to work, we don’t tie the wires in or use a power chain very often because of the amount of friction it creates. This would cause a lot of binding due to the friction, thus causing the benefits of a passive self-ligating bracket to be minimized.

There is a different mindset when using less friction and low forces. We no longer think about how big of a wire can fit in the slot, but rather how to use the lowest force possible to move this tooth and get optimal results.

Which materials and arch-wire shapes work best with self-ligating brackets? Do they work well with other wires as well?

I think the key here is that we understand that we create a tube with the bracket slot with the wire sitting inside, which allows us to have reduced friction and binding to create more amazing arch widths. In my opinion, any wire would work well in a passive self-ligating bracket, but I’ve found that Damon created his arch wire shapes to mimic those of Frankel’s work. Frankel showed that when you balance the facial muscles, the tongue, the teeth and pressures that are involved in the maxillary and mandibular arches, a natural arch form develops. I’ve heard Damon speak about this arch form many times. This shape is such that the first bicuspid—not the cuspid—is the widest part of the arch. This creates a natural, beautiful shape that is broad and wide, supporting the features of the face.

With that being said, if you put any wire into a self-ligating bracket, you’re going to see things work well. Ormco has come up with an excellent combination of copper–nickel–titanium wires that’s very efficient. I often hear of a doctor using the Damon System with another company’s wires and it makes me uncomfortable. It would be like driving a sports car and putting regular octane gas when premium gas is what is recommended. 

What design changes have been most important to you—over the years and/or recently?

The most important design change for me has been in the Damon Q bracket— more specifically, the door design. We call it the “spintek” door, and it opens and closes very smoothly and efficiently. With passive self-ligating brackets, you want to get the doors opened and closed without putting any pressure on the tooth, to avoid causing any discomfort for the patient.

The most recent change that has affected my practice would be the tightened tolerances that have been introduced with the most recent Damon Q2 bracket that just hit the market. With these tightened tolerances, I’ve been able to have more rotational control and confidence with the bracket, creating beautiful results overall.

With so many companies offering these brackets, what qualities do you think clinicians should be looking for as they determine which one to use in their practices?

With so many companies offering these brackets, I think the qualities that clinicians should look for are:

• How long has this company been making PSL brackets?
• Is this just a bracket, or is there a system involved?
• I would also find out how many versions the company has of its current bracket. A company that is dedicated to innovation and change is where I want to buy my brackets from. Every year, Apple brings out an updated version of the iPhone, and people stand in lines to get the latest innovation and technology. I want the same for wires.
• What kind of education does the company provide? Does it provide support resources for doctors to become educated on how to use the system? Does it offer courses and forums to help doctors be better and get better results? 

Some clinicians have expressed concern that self-ligating brackets come with their own challenges or issues. How have you addressed those in your practice so far?

Any bracket and system has challenges—it really comes down to which system has the least of them. PSL can be a blessing and a curse: When you have a tube with a wire that doesn’t entirely fill up a slot, you can see unwanted issues. I think the biggest challenge is space that’s developed; If you’re not careful, you can end up with excess space in the anterior and have to deal with that.

The other issue is wires sliding and causing poking emergencies. I’ve addressed these issues by educating my team on how to set the case up from the beginning, and across every wire interval. We will wire-tie the anteriors when we put rectangular wires in to avoid space opening up, and we will leave the initial wires out of the lower 6s to avoid the wire coming out and poking the patient.

I’ve also heard doctors using PSL say that they can’t finish well … but I’ve found that the doctors who say they can’t finish well with PSL can’t finish well in any other bracket system, either.  

We’ve talked a lot about the clinical perspective, so now we’re on to things patients will ask about. How do self-ligating brackets benefit the patients—are there measurable differences in time, comfort, result or smile? Are there any challenges in persuading patients to use these brackets—and if so, how do you encourage them to do so?

Patients come into my office every day asking for a wider, broader smile. I have people tell me that they’re able to tell if they have been treated by my office just by the way the smile looks: The arches are broader and the arch shape looks different than traditional tie braces.

Many of my adult patients going through braces for a second time often comment, “These don’t hurt anywhere near as much as the last time.” With the older twin brackets, patients remember being in pain for four to five days, but my patients generally aren’t sore for more than a day or two. My patients also comment on how the brackets are more comfortable and less sharp than other brackets.

Although kids love color O-ties, parents love the fact that the Damon system has a door instead of using the colors, which can collect plaque and food.

The other comment patients make is that they love the fact that they don’t have to be seen for 10 weeks between appointments.

Overall, I think the biggest thing that patients love about self-ligating brackets is the idea that orthodontic technology has changed for the better. People see all the technology changes in the world and they expect that the orthodontic community has changed as well. They love knowing they have the latest and greatest bracket and wire technology being used to straighten their teeth and create a beautiful smile.

If you told me tomorrow that I couldn’t use passive self-ligation, I would seriously consider retiring! I could not be the orthodontist I am today without it.