We talk to Dwight Damon about orthodontic research and development.
Dwight Damon: Dr Dwight Damon is the inventor of the Damon System. He works in the private practice of orthodontics at 12406 E Mission Ave, Spokane Valley, WA 99216, USA.
What do we know you for?
People recognise me for the development of the Damon Bracket System, a passive self-ligation fixed orthodontic appliance.
I trained at the University of Washington in 1970. Before dedicating my career to improving treatment quality in terms of shortening treatment times, increasing patient comfort.
The aim was to reduce chairside time, whilst simultaneously not compromising the overall facial aesthetics of his patients.
I run an orthodontic clinic in his native Spokane for 40 years. My son, Paul is also an orthodontist and lecturer in the Damon System.
Tell us more about the system?
The Damon System combines passive self-ligation brackets, and force calibrated archwires to give us low friction. The philosophy that using biologically sensible forces improves both tooth position and facial aesthetics underpins the system.
In today’s orthodontics, there is an ever-increasing emphasis on the quality of the smile and how it contributes to the overall facial appearance.
What prompted you to develop a self-ligating bracket system?
It motivates me to keep learning, and improving the treatment and care of my patients.
The idea that force levels for clinical mechanics came from a patient tolerance rather than their positive or negative impacts on tissue was one that I questioned early in my career. It seemed that if teeth did not move, most clinicians increased the applied force as a solution.
It fascinated me, how little force it took in some tissues to interrupt vascular supply.
We still don’t totally understand the mechanism for tooth movement. However, it makes sense to me that maintaining vascular supply to alveolar bone and tissues must have a positive impact on tooth movement and bone and tissue responses.
I also observed that there was a significant difference in clinical responses when tying initial light-force archwires with elastomerics versus loosely-tied wire ligatures.
Obviously, the archwire has to slide through the brackets to allow teeth to move and align. It simply makes sense to start cases with very lightforce archwires. That could express themselves in a reduced friction and binding environment of the archwire-bracket interface.
There is a misunderstanding in our profession about the role played by friction and binding in the performance of clinical mechanics.
What was the next step?
I tested my theory on typodonts. I found there was a significant difference between the two tying methods in the amount of force it took to slide an archwire through irregularly positioned bracket slots.
Taking the next step, I cut bracket-size .022” × .028” tubes. I bonded them to irregularly positioned lower anterior teeth on a typodont.
It impressed me, how much less force it took to slide the archwire through tubes versus those archwires that were tightly tied with elastomerics or wire ligature ties.
I tested my theory clinically by bonding bracket-size tubes on a very crowded lower arch of a close friend. I’m astonished at the clinical response when using small dimension light-force archwires.
It was also obvious that our practice spent most of the day removing and inserting archwires. It only made sense that there was a significant need for an easier and quicker way to accomplish this task.
I tried two of the self ligating brackets in the marketplace at the time. But soon found that I didn’t want to give up the twin-bracket configuration.
I also desired to take advantage of low-force sliding mechanics in a tube configuration that I had previously tested.
How did you then develop the Damon appliance?
I started drawing passive self-ligating brackets in the late 1980s. Due to limitations in manufacturing technology, it was challenging to design small brackets that included very small moving parts.
We cast the first Damon bracket body. However, the opening and closing slide was stamped. This made it difficult to control fit and performance.
I bonded my first patient with the first Damon passive self-ligation bracket in 1993.
Even though there were significant clinical issues with reliability, it was obvious that this technology had tremendous potential for improving clinical performance; it seemed like it could be a significant step forward for patient care.
The big manufacturing breakthrough came when injection moulding came to orthodontics. This allowed significant freedom for bracket design and dramatically improved bracket fit, contours, reliability, and performance.
This was a long time ago, so how would you describe the Damon appliance system today?
All brackets designed and brought to the marketplace for the Damon System have featured passive self-ligation.
Its success is down to a carefully designed system.
This system utilises specific archwire progressions to enhance clinical management of lighterforce mechanics.
Many clinicians feel that by utilising lighter-force, lower-friction mechanics, they see a positive impact on bone and tissue, with more treatment-planning options for the maturing adult face.
What are the advantages of a self-ligating system in terms of mechanics and biology?
This is difficult to answer briefly because the advantages for the clinician are numerous.
If the goal of any clinician is to use clinical mechanics that produce more ‘wanted forces’ than ‘unwanted forces’, then self-ligation is a significant step forward in achieving these goals.
The in vitro Orthodontic Simulator (OSIM) studies done by Dr Hisham Badawi at the University of Alberta clearly substantiate the significant mechanical advantages of self-ligation over conventional mechanics.
The expression of early light-force archwires produces far different forces and moments, both in magnitude and direction.
Dr Badawi found more wanted forces and fewer unwanted forces with passive self-ligation than with conventional ligation. This allows the clinician more opportunities to treat patients without extractions.
The Damon System has allowed more than four million patients to get treatment. The evidence strongly supports a positive impact on bone, tissue, and facial outcomes.
Biological advantages are hard to substantiate with research. However, I think the most compelling evidence is what clinicians see day after day in their practices.
Many clinicians comment on the positive tissue and bone responses they are seeing. Even in periodontally compromised patients.
The management decision to bring Insignia to the marketplace as a passive self-ligating bracket speaks strongly for passive self-ligation.
What about treatment efficiency?
Regarding treatment efficiency, appointment intervals can be lengthened early in treatment to allow time for the ‘biologically sensible’ light forces to express themselves.
Research studies show a decline in both the number of appointments per patient and treatment times. I also hear many clinicians mentioning that early lightwire alignment happens in less time. This gives the clinician more time to detail and finish.
However, I want to make it very clear that case management varies greatly from office to office. This has a major impact on treatment efficiencies.
For this reason, my focus in lecturing for the past 10 years has not been on the speed of treatment or the decrease in the number of appointments. Rather, it has been on how and why this technology expands treatment options and improves the quality of patient care.
This technology helps patient flow due to how quickly we can change archwires.
For those clinicians with excellent case management, research shows that the number of appointments decreases and treatment time shortens.
Chairside assistants become proficient in handling archwires very quickly. It’s a good feeling to leave the office at night knowing that every archwire on every patient is fully engaged in the bracket slots.
Thanks to the ease of getting archwires in and out, the clinician can accomplish every desired task at every appointment without upsetting the schedule.
How does the cost of a self-ligating bracket system compare to that of a traditional bracket system?
While the initial price for any self-ligation bracket is more than that of traditional brackets, the benefits far outweigh the cost.
With longer appointment intervals and fewer auxiliary appliances and extractions; with outstanding case management, many clinicians have also found faster treatment times.
My decisions on what technology to use in my clinic hold a basis on what I perceived would help deliver the best quality of care for my patients.
There is no question that self-ligation has dramatically improved my chances of meeting my challenging goal. This is that: ‘Straight teeth should never come at a long-term high cost to the periodontium or the face.’
Are there differences in the Damon approach to treating adolescent versus adult patients?
Living in a smaller community where many patients tend to stay in the area has given me the opportunity to follow a significant number of them for many years in retention.
Carefully evaluating these patient outcomes has had a profound impact on my clinical mechanics and treatment planning. For the past eight years, we have used an in-office cone-beam computed tomography (CBCT) scanner to help evaluate some of these patients in retention.
I can say with conviction that passive self-ligation and the Damon System definitely have expanded treatment options for adults. It revealed positive long-term radiographic results.
What we have learned from these scans is that researchers should be very careful with post-treatment timing when the desire is to evaluate the presence or absence of alveolar bone.
It is strongly advised to wait several years after treatment. This allows bone densities to be high enough to be picked up and to show on these scans.
At this time, medical CT scans are still far more diagnostically thorough in evaluating the presence or absence of alveolar bone.
Unfortunately, the cost and radiation exposure of medical CT scanning is a deterrent. However, utilising lower-radiation CBCT technology, I have seen enough long-term retention evidence.
It concludes that the gap has narrowed in treatment opportunities between adolescent and adult patients.
Another interesting side issue is that periodontists in my practice area were once reluctant to send patients for orthodontic care. They now see a significant benefit for many of their periodontally involved patients in seeking Damon System treatment.
Further details on the Damon System and courses can be found at https://www.ormcoeurope.com.
This article first appeared in Orthodontic Practice magazine. You can read the latest issue here.