In relative terms, the TAD is a fairly recent addition to the orthodontist’s toolbox. But the TAD—or Temporary Anchorage Device—has its genesis decades ago: rigid fixation screws which were a collaborative effort that came about when orthodontists and oral surgeons innovated in treatment planning.
But the modern TAD came into existence around 1997 in East Asia. During the following ten years, the world economy was in a period of robust growth and companies were investing heavily in R&D. Most of the so-called big players in the dental product manufacturing sector were quick to spot opportunity and were developing and aggressively marketing TADs. By the mid 2000s the temporary anchorage device was showing up in many orthodontic practices.
Then in 2007, the economy stalled. All the momentum that TADs had generated waned with this downturn and companies reduced their marketing and educational support. However one doctor’s unusual educational background left him uniquely qualified to continue working and innovating with the TAD.
Daniel L.W. Fishel is a DMD in south central Pennsylvania. After earning his dental degree at Harvard, he completed a unique four-year combined residency in periodontics and orthodontics at the University of Pennsylvania School of Dental Medicine in Philadelphia. It is the only residency of its kind in the United States, making him one of approximately 25 specialists in the United States certified in both orthodontics and periodontics. This exceptional educational background, combined with the natural crossover that exists between implant dentistry and TAD usage, made him one who never walked away from the TAD.
We sat down to talk with Dr. Fishel about the past, present and future of what is still a relatively new piece of hardware at the doctor’s disposal.
Thank you for meeting with us. Orthodontics existed for decades without TADs. Why all of the sudden did this new treatment tool get invented?
The TAD itself was developed because of the limitations of traditional orthodontic treatment. Orthodontics is very humbling. The amount of movement you can get is quite small. While not absolute, most doctors can achieve a maximum of around 4mm of true bodily tooth movement in most situations.
When you need greater dental movements or skeletal correction, the next step is traditionally orthognathic surgery. But this is a significant jump. The TAD is really a treatment option between braces and surgery. It allows you to get that extra tooth movement you couldn’t with traditional treatment.
Using a TAD lets you comfortably transition into treatments of 4 to 6mm of bodily tooth movement, as well as transverse skeletal corrections of the maxilla. Hence, you’re pulling someone out of a surgical category and putting him or her back into an orthodontic category. That’s significant.
Who is using TADs today?
You’re much more likely to find younger doctors who were exposed to TADs in school during university training using them. If not exposed to TADs in school, many orthodontists took a class on TADs in the mid 2000s…they bought the kit, tried it a few times and most likely, they had mixed results: some success…some failures. But doctors are business owners, and the failures weren’t good for business.
In addition, TAD usage wasn’t necessarily a good fit financially for practices. During the learning phase, it could take an orthodontist up to an hour to place a TAD or TADs. From an hourly revenue standpoint, especially as orthodontists experimented with systems to integrate TADs into their practices, production was a lot less than what could be achieved from a more traditional orthodontic approach.
Another thing that happens is basic comparison shopping. If I see a patient and recommend TADs, they (the patient) can then go down the street and have a doctor present a much more traditional plan that’s going to cost less, and not have extra procedures and appliances. The patient doesn’t necessarily understand the difference in result. They just know that my plan is more involved and my plan is more expensive. They’re going to go with the cheaper guy.
So, frustratingly, my feeling is TAD education and usage has not maintained the momentum needed to fully benefit the orthodontic population.
“Using a TAD lets you comfortably transition into treatments of 4 to 6mm of bodily tooth movement, as well as transverse skeletal corrections of the maxilla.”
What’s the most common use for TADs?
For me, the most common usage is as a bony anchor for expanding the palate, followed by use under a Nance button or TP bar to retract maxillary anterior teeth in Class II correction. The vast majority of my TAD use is in the upper jaw.
Why is that?
First and foremost, narrow maxillas and retrognathic mandibles are the two most common skeletal patterns leading to malocclusions I see in my practice.
Through experience (including many failures) and cone beam verification, I am not achieving significant true palatal expansion after age 11 in my patient population through traditional means. We know that the ideal time to achieve palatal expansion is at 7 to 9 years of age. To this day, unfortunately, many dentists and parents are under the impression that the best time to treat a child is once all the adult teeth have erupted, which usually means in the range of 12 to 14 years of age. But, by that time, the sutures in the upper jaw have largely hardened, making it difficult or even impossible to expand the palate. However, with TADs placed in the palate as bony anchors during rapid palatal expansion, I am able to achieve reliable and comfortable transverse skeletal correction through at least age 14. This is an extremely useful treatment tool considering that a large number of my patients first present after age 11.
I also feel that I am not able to significantly influence mandibular sagittal growth at any age; therefore, TAD use for retraction of maxillary anterior teeth to compensate for Class II growth patterns is also a very useful tool in my practice.
Why not just use the molars to anchor the RPE?
As long as the expansion is rapid enough, you can in theory expand the palate later, but with much greater discomfort to the patient. The place you especially run into problems is when the expansion isn’t aggressive enough. We don’t want the molars to absorb expansion forces (due to fusion of the midpalatal suture) and start to tip buccally, giving a false sense of bony expansion. This is especially true with patients over the age of 11.
With TADs, we are trying to bypass the teeth. By using TADs in the palate, we’re able to push directly against the bone, rather than anchor the RPE only on the teeth.
Do you ever use TADs in the lower jaw?
Not that often. TAD use is limited by anatomy. The lower jaw is a stronger, denser bone than the maxilla. In theory, achieving TAD stability should be easier in the mandible. However, keratinized tissue is much more abundant in the maxilla and not so much so in the mandible. We’ve learned adequate keratinized tissue is pretty important when it comes to success.
Early adopters of TADs, myself included, ran into failure when placing TADs into thin and/or unkeratinized gingival tissue. That’s because without thick keratinized tissue, you don’t get that tight, immobile seal forming around the shaft of the TAD. This lack of a stable seal can lead to gum inflammation and even infection, which can lead to loosening of the TAD.
In addition, patient comfort is an important consideration. It’s not comfortable having the head of the TAD on the lingual of the mandible, irritating the tongue.
Do you need to put someone under to place a TAD?
No. You just need local anesthesia. Some say a topical anesthetic is adequate, but I now always use local anesthesia. I haven’t had great success with topical anesthetic alone. Luckily, regardless of how you anesthetize, you just need to anesthetize gum tissue since there are so few (if any) nerves in the bone itself.
Why do you think so many orthodontists remain resistant to TAD usage?
I think there are a couple of reasons orthodontists are resistant. First is the success rate. Many tried placing and using TADs a few years back and didn’t have great luck. Maybe the mechanics weren’t well thought out. Maybe they had an irritated or infected TAD site, or a TAD got loose. Whatever the reason, their initial success rate may have been in the 60-70 percent range, as mine was…and that wasn’t acceptable.
If we’re speaking honestly, another reason is price. I’ve seen dental specialists charge $200 per TAD, all the way up to $500 or $600 per TAD. So you could be starting out with over $1,000 worth of additional expenses before the orthodontic treatment even begins.
That can be a huge non-starter for patients/parents. It doesn’t take many declined treatment plans of this nature to make an orthodontist/business owner gun-shy about recommending TAD-assisted treatments in the future.
A sixty percent success rate seems low. What sort of success rate do you get?
I’m now well over 90%, which is a realistic number for just about anyone who takes into consideration the anatomical and mechanical issues previously discussed.
Do you need to create a guide hole when placing a TAD?
No. Remember that a lot of R&D was performed in bringing these to market. TADs have been engineered to be ‘self drilling and self tapping’. If you’re looking for a real-world comparison, they’re like drywall screws: no pre-drilling is needed.
The average diameter of a TAD is 1.5 to 2.5mm…so quite small. When inserting a TAD into average density bone, the TAD simply punctures and compresses the surrounding bony tissue as it is inserted without the need for a pilot hole.
How are TADs placed?
There are two main ways. Most are familiar with placing a TAD with something that looks like a screwdriver. There are custom handles and driver bits for every TAD brand, and you simply screw the TAD in manually. You can also use an electric implant handpiece where a latch driver is used in the implant handpiece. I much prefer this method as it gives better access and control, especially in the palate.
You’ve mentioned TAD success. Can you define success?
Good question. Success with TADs is actually a two part contingency. First, does the pin stay tight and stable? Secondly, did you pick a good location to place it? Once you’ve established the first part, stability, the second part is functionality. Is the pin usable? You can have a solid placement in dense bone and thick tissue that heals nicely, but if it’s not useable, (by definition) it’s useless. Sounds obvious, but it’s important.
What about the other side of the coin, what are the most common causes of failures?
Well I’d like to reiterate that failures are now pretty uncommon, especially with the use of cone beam technology in deciding location of placement. But, look, anytime you’re working with human anatomy, there are many variables. Sometimes you’re going to place a TAD in bone that’s not as thick or dense as you want. Sometimes you’re going to get infections beyond your control. Believe it or not, tongue pressure is also a concern. As we know, the tongue is among the strongest muscles in the body. If you’ve got a patient who can’t stop playing with the head of the pin, they can loosen the pin.
Speaking of infection, how do you prevent it?
We have the patient rinse with chlorhexidine mouthwash for 30 seconds prior to TAD placement. But we’re also reliant on the patient to have good oral hygiene when they leave the office.
If the TADs make it through the first week, you’re pretty much in the clear. The gums will heal around the TAD creating a tight seal around the shaft of the pin, preventing bacteria from penetrating the site.
So how long are TADs typically placed for?
I can only speak for myself. When I’m doing a TADassisted palatal expander, it’s about four months. That’s two to three weeks of expanding the jaw…and then another three months to let the bones heal. For bodily movement of teeth with TADs, I plan on about 0.75mm – 1mm of tooth movement per month.
What about removal of the TADs?
In the 2000s, the school of thought was to use topical anesthetic around the head of the TAD and simply unscrew it. However, I still like to get the patient numb with local anesthetic. The soft tissue will largely heal within two to three days since the mouth, and really the whole digestive tract, heals faster than just about any other part of the body. But yes, it’s pretty straightforward.
So what’s the future of TADs?
What’s unfortunate is that TADs were really at their biggest during 2006 when companies were pumping a lot of money into R&D, clinical demonstrations and marketing. But the bad economy hit in 2007, and that’s when excitement really tapered off.
Even today, discretionary spending among patients remains down, and so many doctors are hesitant to start adding costs and treatment complexity.
What’s really unfortunate is that the overwhelming majority of the public is going to be happy with the upper front six teeth being straight. As long as little Johnny has a nice smile, the parents think it’s a success. But the public doesn’t understand the importance of a good bite. A bad bite can have some pretty serious long-term consequences.
The CCO group, which I’m part of, is looking to do more than just provide straight teeth in the most efficient means possible. We want to provide a good bite as efficiently as possible. This will provide good long-term oral health. The TAD is another tool we have to provide good occlusions efficiently from both a time and financial standpoint.
Thank you for your insight Dr. Fishel!
You’re very welcome!
Dr. Daniel L. W. Fishel, DMD is dual specialty trained in orthodontics and periodontics. He completed his dental training at the Harvard School of Dental Medicine and his residency training at The University of Pennsylvania. He practices in multiple locations in south central Pennsylvania, including Harrisburg, York, and Hanover. He emphasizes educating his patients on the best treatments dentistry has to offer, providing orthodontic, periodontal, and dental implant treatments that maximize dental health and longevity, as well as quality of life.
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This article published in 2013 OrthoWorld.