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Antonino Secchi, DMD, MS
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Dr. Secchi is Assistant Professor of Orthodontics-Clinician Educator and Clinical Director of the Department of Orthodontics at the University of Pennsylvania USA and Visiting Professor at the University of Los Andes, Chile. Dr. Secchi received his DMD, Certificate in Orthodontics, and a Master of Science in Oral Biology from the University of Pennsylvania. Dr. Secchi is a Diplomate of the American Board of Orthodontics and member of the Edward H. Angle Society of Orthodontists. At the University of Pennsylvania, he has developed and implemented courses on Orthodontic Treatment Mechanics, Straight Wire Appliance Systems and Functional Occlusion in Orthodontics. In addition, he maintains an active orthodontic practice at the Dental Care Center of the University of Pennsylvania. |
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Dear Dr. Choudhary,
The Damon 3 bracket system comes with only one prescription values, the Damon Rx. However, the Smart Clip and the In-Ovation bracket systems come in different prescription values such as the Roth Rx, MBT Rx, Ricketts Rx, etc. I would suggest you to go to the following links to have a specific and complete list of the different prescription values available for these SL systems:
http://www.gacintl.com/UserFiles/File/DGAC-%20Catalog14%20LR.pdf
http://www.ormco.com/ormco/ormcocatalog-7mb.pdf
http://multimedia.3m.com/mws/mediawebserver?mwsId=SSSSSu7zK1fslxtUOxmBOx_Uev7qe17zHvTSevTSeSSSSSS--&fn=016-851.pdf
Regards,
Antonino G. Secchi, DMD, MS
Dear Dr. Sanu,
My sincere answer is that I do not know. Since mixing bracket systems with different molar tubes/bands is quite common for many orthodontists and I have not heard too many complains about it, my impression is that most likely you would be fine.
However, in theory, you could have problems with the alignment of the posterior part of the arch. Remember that every tooth has a different buccal lingual prominence and therefore, in the straight wire appliance every bracket has a different in/out, so teeth can be all properly aligned with a straight wire.
Now, if you mixed brackets with different profiles (buccal lingual width) you will have a hard time aligning those teeth. Well, the same thing can happen if the profile of the molar tubes/bands is not in agreement with the rest of the brackets. Unfortunately, the numeric value and proper ratios of profile for different brackets systems and tubes/bands are easy to find.
Regards,
Antonino G. Secchi, DMD, MS
Dear Dr. Torres,
Torque control is a known huge problem of passive SL systems. As you have already experienced, this can be an important challenge to overcome at the time of finishing. Proper torque control is a feature that a true straight wire appliance must be able to deliver.
Research done in this area has shown that active self-ligating systems are far superior in delivering torque when compared with passive systems. Interestingly, in vitro and in vivo studies have shown no difference between passive and active SL systems at the beginning of treatment when less friction for the initial leveling and aligning stage is preferred.
You can grab one of your passive brackets and a .021” x .025” ss or even a .0215” x .028” ss wire, engage them in your hands, and move the bracket through the wire. You will be shocked by the amount of play (lack of control) the passive bracket has on such a large archwire. Then, you can do the same with an active self-ligating bracket such as the In-Ovation ‘R’ or ‘C’, and you will see and feel the difference.
In my personal clinical experience, I have not encountered problems with torque control with the active self-ligating appliance I use.
Regards,
Antonino G. Secchi, DMD, MS
Dear Dr. Walker,
I have not seen the wire being worn with sliding mechanics when using the In-Ovation ‘C’ bracket system. Actually, I would say that the In-Ovation ‘C’ is a great bracket for sliding mechanics, even better than many of the available metal brackets. It is made through a ceramic-injection-molded procedure that enables it to have a very smooth slot surface, the ceramic slot does not micro-corrode, and it has a chamfer (beveled edge) on the walls of the slot to prevent notching. Today, the In-Ovation ‘C’ is definitely my first choice of self-ligating aesthetic appliances.
Regards,
Antonino G. Secchi, DMD, MS
Dear Dr. Kowalchuk,
I have seen deep bite cases treated with the mechanics you mention and personally, I have not been convinced with the results I have seen. I would be worry about the stability of those cases. Not every deep bite case has loss of VDO. It is different to have a case with loss of VDO due to missing of posterior teeth and periodonticaly compromised anterior teeth that are severely proclined, commonly found in cases with posterior bite collapse, than to have a more typical orthodontic deep bite case with a reduced lower facial high. To change the VDO via orthodontics could produce undesired functional and aesthetic consequences.
We all remember when we were in dental school and were fitting complete dentures to the wrong VDO. The patient could not talk or swallow comfortably. Also, as you increase the VDO, the mandible rotates downward and backward, which produces, in many patients, a negative effect on facial aesthetics.
In orthodontic cases, I usually correct the deep bite by leveling the occlusal plane. Although it sounds simple, and it is in many cases, in severe brachiocephalics, this can be a challenge.
After stage one is completed, initial leveling and alignment with thermal activated wires, I place a .019” x .025” stainless steel wire, my working wire. Usually after one visit with the .019” x .025” stainless steel wire, I add to the lower wire reverse curve of Spee. The amount varies according to the severity of the problem. In severe cases, I go up to a .021” x .025” ss wire with reverse curve of Spee. That extra stiffness of the wire helps to flatten the occlusal plane.
At this time I ask the patient to wear short class II 3/16” 6 oz elastics from the upper canine to the lower second premolar. It is important to consider the amount of space available in the lower arch, since leveling the curve of Spee will procline the lower incisors. This can be desired or undesired depending on the case. Also it is important to consider the amount of torque of the upper incisors. Often, in deep bite cases the upper incisors are retroclined. Proper upper incisors inclination (torque) must be achieved to allow the lower incisors to move forward.
Regards,
Antonino G. Secchi, DMD, MS
Dear Dr. Dizon,
It all depends on how big is the residual space you have to close and the anchorage requirement of the particular case. But generally speaking, I could give you the following suggestion.
First you have to level and align. You will be surprised at how, after this stage of treatment, oftentimes the spaces get significantly smaller.
Then, on my second stage of treatment, the working stage, if the residual spaces left are in the range of 2 mm, I would just use a C chain on a .019” x .025” stainless steel wire.
Now, if the spaces left are bigger, I would use a Sentalloy coil (Yellow dot, 150 gr for dolicocephalic and mesocephalic patients and Red dot, 200 gr for brchicephalic patients) attached from a crimpable hook, that I usually put distal of the canine, to the hook of the first or second molar depending on the anchorage situation. The Sentalloy coils can be activated about 3 times their initial length. Most of the times I use a .019” x .025” stainless steel wire for my closing mechanics. I have found that this wire is the best for sliding mechanics with the In-Ovation brackets.
The idea is to have a wire with the right size and stiffness that allows the bracket to slide through it with control. A smaller wire may look at first like a good option due to the apparent reduced friction, but if is not stiff enough and or if there is too much play between the bracket and wire, teeth can rotate, incline, occlusal plane unlevel, etc, and then the system becomes less efficient.
Regards,
Antonino G. Secchi, DMD, MS
Dear Dr. Takreeem Rehman,
I am very sorry. I am currently not acquainted with this brand of self-ligating brackets.
As time goes by, more and more companies are seeing the advantages of self-ligating brackets, and are introducing many variations. I have not had the opportunity to try this bracket.
Thank you for your question.
Regards,
Michael C. Alpern, DDS, MS
Dear Dr. Keith Harvey,
The subject of active or passive has degenerated down to marketing. What seems to be lost in the question is "evidence-based knowledge."
I have found that truth is not a word game. Orthodontic brackets interact with orthodontic arch wires. This interaction moves teeth. Therefore, at some point in time the main archwire has to have some contact with the bracket slot. Thus, no bracket system should be labeled "passive" or even "active."
"Interactive" is a more accurate term. Depending on the size and shape of the orthodontic wires and the bracket slot's design, sometimes there is an active relationship between the wire and the bracket, causing tooth movement. Conversely, sometimes the wire and the bracket have achieved the desired tooth movement and a "passive" state exists between the two.
Orthodontic biomechanics requires tooth movement sometimes, and no tooth movement at other times. The key here is CONTROL. I have written about "control" in several articles including, "Gaining Control of Self-ligation" published in Seminars in Orthodontics, Volume 14, No 1, March 2008, pages 73-86. I have also published, "Complete Control" in Orthodontic Products. The AAO library and Orthodontic Products should be able to supply you with copies.
In my mind, orthodontic mechanotherapy requires that we have control of tooth movement. Therefore, sometimes my systems are active and sometimes passive, but mostly they are interactive. All wire-bracket contact occurs with as much control between the archwire's size (and metallurgy) and a correctly manufactured self-ligating bracket with exact corner radius tolerance of the interior walls of the bracket slot as possible.
Michael C. Alpern, DDS, MS
Dear Dr. Porter,
Thank you for your question. I will answer with a brief introduction of the philosophy I use towards all self-ligating brackets.
I regard self-ligating brackets as an additional, advanced component to my existing orthodontic mechanotherapy. In my practice, I place nearly every single wire. In the past, I have permitted my assistants to steel-tie brackets, with me checking the patient before discharging them. Full steel-tying every bracket is labor-intensive and varies based on who is tying the metal ties. If the archwire is not fully engaged into the bracket slot, then full correction does not occur. Steel ties can come loose, trap food, and are often uncomfortable. And changing upper and lower archwires with each bracket steel-tied takes time. More importantly, each time a ligature wire crosses the archwire, there are two points of friction. Thus, one steel tie creates four points of significant friction to sliding and other movements.
If a self-ligating bracket has a steel, alloy or titanium spring closing clip, now for the first time, I can have spring-flex in the wire and spring-flex in the closing clip. Depending on the design, some closing clips have a bracket stop to closing. You might want to research my article, "Gaining Control of Self-Ligation," published in the March 2008 (Vol 14, No 1) issue of Seminars in Orthodontics.
I have used Speed, Innovation R & C, and American Orthodontics T3. All appear to have a flexible, spring clip. Advantages: 1) Saves time in changing archwires. One example for me is during my afternoon, after-school "observation appointments." How many times during this time have you wanted to slide an existing arch partially out of the molar tubes, make adjustments and reseat the archwire? It takes me less than 3 to 5 minutes to open 4 to 6 brackets, slide the archwire partially out, make adjustments, and re-seat.
If patients floss every tooth every night and maintain a good diet, teeth appear to move faster when there is less friction. Under the correct circumstances, self-ligating brackets can shorten treatment time. However, with poor oral hygiene and no flossing and poor nutrition, self-ligating brackets are no more effective at tooth movement than any bracket.
Patients who develop significant calculus (even with dental cleaning every 3 months) can present challenges to self-ligating brackets. Calculus can adhere to the sliding, closing clips of self-ligating brackets. Thus, normal opening may not be possible. We have three cavitrons in our office and use them to open self-ligating brackets that are immovable due to calculus. There are initial studies in the literature to determine if self-ligating brackets collect more or differing bacteria. Time will illuminate this potential problem.
Self-ligating brackets do cost more. However, after 8 to 10 years of using them, all I have to do is have a transfer patient who came in with steel-tie ligatures and steel-tie in one upper and lower archwire, and I am convinced that self-ligating brackets are my future.
Your question is which brand would I recommend. I would try 20 cases of differing brackets and see which system you find the most efficient. How easy is it to open and close the clip? Do the clear systems break too easily? The reason for my hesitancy to name a brand and recommend that brand is "technology." Many companies have significant efforts directed toward improving and innovating self-ligating brackets.
A good friend of mine always said, "If you quote me, date me."
Regards,
Michael C. Alpern, DDS, MS
Dear Dr. Romabel Asaytuno,
Thank you for your question.
As I understand your question, you would like to know the significant difference and advantages of self-ligating brackets compared to other straightwire bracket systems.
The self-ligating systems I have used are all straightwire bracket systems. The primary difference for me is I do not have to use stainless steel ligatures to secure the main archwire to each bracket. For more than 20 years, I primarily used stainless steel ligatures ties, all twisted into pigtails and cut to approximately 2 to 3 mm long. These stainless steel ligatures were labor-intensive and how snugly they were tied to the bracket slot varied as to whether I tied them or a certified orthodontic assistant tied them.
The main problem with steel ligature ties is friction. Each stainless steel ligature crosses the main archwire two times (mesial and distal of each bracket). As each portion of the ligature crosses the main archwire, there are two friction contacts. One friction contact is where the wires cross the incisal edge of the archwire and the second friction contact is at the gingival edge of the archwire. These friction contacts limited sliding mechanics. Also, stainless steel ligatures have almost no elasticity, further limiting sliding mechanics.
The self-ligating brackets I have used all have a flexible closing clip which replaces the stainless steel ligatures. Thus, there is less limitation to sliding mechanics. The self-ligating brackets I have used all have a closing clip stop on the bracket design. Thus, once the closing clip contacts the stop on the bracket—in the correct-sized wire—the closing clip does not touch the main archwire. Most importantly, in the wire sequence I use, the closing clip is sometimes active (seating the wire fully into the bracket slot), and sometimes passive. In a passive situation, the main archwire is seated (producing full 3D tooth-positioning control), yet the main archwire does not contact the closing clip.
I have published two articles on this technique. One, published in Orthodontic Products, is entitled "Complete Control." The other was published in the March 2008 (issue Vol 14, No 1) of Seminars in Orthodontics, pages 73-86, published by Elsevier. These two articles more completely and visually explain these advantages.
Another advantage of self-ligating brackets is the time savings in changing maxillary and mandibular archwires. Time is also saved when making small intraoral archwire adjustments. I open the closing clips adjacent to the adjustment bends I plan to make in the archwire. Then, I make the adjustments (without breaking the brackets off the teeth) and efficiently re-close the flexible bracket clips.
In my treatment regimen, I begin using Nickel and Beta Titanium wires (all .018 x .018 in a .018 slot size). Thus, I fill the bracket slot vertically, gaining control for the initial wires. The forces applied to the teeth are light, individualized forces. Because the closing clips and wires are flexible, I postulate that I am using lighter, continuous forces, achieving more rapid tooth movement in a safe manner.
There are disadvantages to ligature-less brackets. They do cost more. However, to me, the time savings (mentioned above) and reduced sliding friction make up for the increased cost.
The self-ligating brackets I use seem to collect slightly more calculus. There are initial studies indicating that slightly more and/or differing types of bacteria collect around these brackets. We try to stress to patients that more rigid oral hygiene is required. In a significant number of adults, their calculus adheres not just to the teeth and the bracket base, but also to the sliding mechanisms of the closing and opening clips. We have found a significant number of patients require a Cavitron to remove the calculus and open the flexible clip. The ultrasonic cavitation of these cleaners also tends to help clean the slots which the closing clip must slide through in order to function.
I have used self-ligating brackets for nearly 10 years. These brackets have not changed my basic treatment philosophy. In spite of the disadvantages and cost, I think they will continue to be more common in orthodontic practices. Innovations in self-ligation will continue to make these brackets part of our future.
Thank you for your question.
Regards,
Michael C. Alpern, DDS, MS
Dr. Marco A. Pinto
Specialist in Orthodontics and Dentofacial Orthopedics
Antonino Secchi,
DMD, MS
Straight Wire Appliance,
Self-ligation,
Treatment Mechanics
Richard Cousley BSc, BDS, MSc, FDS, FDS(Orth) RCS
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