Friday, May 22, 2009

Frequently asked questions, part 2

I'm using lacebacks on an extraction case. One question: when the lacebacks are tied in, with the wire on top, is there enough room around the brackets for elastic ties or would you have to use the ligature ties to tie everything in place?

I use elastic ties when engaging the wire. There is plenty of room on the bracket tie wings for both the laceback and the elastic tie.

What kind of burs do you use for IPR?

I use Essix burs. Find them here- . The specific burs I like are the 55000 for anterior reduction and the 699LC and 848MD for posterior teeth.

An issue that I am struggling with is re-bracketing. In the first scenario, a patient breaks a bracket, say in the 020 or rect wire stage. Some tooth movement seems to have occurred since the break. How far do we have to go back in wire progression to catch up? I have found that I'm often using 016 Niti to get the new bracket and tooth in line. But what then? Second, after repositioning for second order movement in mid-course, I'm going to 016 Niti, but then can't seem to get right to the rect niti next month because it won't fit that tooth position. Is there a certain way to reposition brackets that will speed the process? What if a patient is breaking brackets every other appointment? Biting fingernails?

The first rule in re-bracketing or repositioning is to be efficient. In your 1st case, even if you were in .020, I would re bracket that tooth at the same time I repositioned. If I had time, I'd do it that day. If not, leave the tooth unbracketed and schedule a longer appt. for repositioning in a month. One of the beauties of ortho is you can delay or speed up things depending on your schedule at that particular time. This is not the case with most other dental procedures.
To answer your 2nd question, if you can't go directly to 019x025 niti from 016 niti, use an 016 st steel wire for a month. Again, not all patient's teeth move exactly the same way, so sometimes we have to adjust on the fly. Position the brackets correctly (there is no magic here) and use the wires you need.

Breaking brackets is a whole different issue. Poor coop takes all the fun out of ortho. Look in my "policies" handout which I gave out in the last course. We charge the pt $20 per bracket after they have broken off 10 (most orthodontists start charging after 5). You will be surprised how quickly the situation improves after the parents get a few extra bills.

1) The bracket on LR4 has come off between just about every adjustment; however no other bracket has come off! FYI, I do have a few ortho cases going and haven't had problems with brackets coming off...this is starting to frustrate me! Any troubleshooting advice? (I have even placed a NEW bracket, just to be sure)

2) Do you have any info on how to place koby hooks?

3) According to USDI guidelines, the consolidate stage is to close posterior spacing, so if it's a non-extraction case, do you generally skip this stage? And are lacebacks your preferred method of closing space? I have heard of k-modules, chain elastics, etc. Which ones work best in which situations?

Brackets consistently coming off is a frustrating problem. It's usually related to occlusion. When you re bracket, make sure it is not interfering. You can relieve interferences by adjusting the bracket (usually a tie-wing is the culprit) and by also doing a minor adjustment on the opposing tooth.
I usually place Koby hooks under the archwire. Then you don't have to remove them on every wire change. Just tie it in like you would a steel tie. Be sure to pull tightly on the pigtail as you twist. After tightening, deflect the hook to where you want it to go by using a ligature director. Then tie the wire in as usual over the hook. The Koby hook gains stability when the wire is tied in.
Lacebacks are used early in extraction cases to control anchorage (that is initial retraction of cuspids into the extraction site without any forward molar movement) so, technically, they are not a method of space closure. Any elastic force can be used to close space. Power chains, k-modules, elastics, open coil springs, etc. all work. Use what works best in your hands. Personally, I use elastics (1/4" or 3/16" medium ) until the space is about 2 mm. Then I use power chain. I think the archwire used is more important than the type of force. To maintain good torque control, I like to use heavy rectangular wire during space closure.
Finally, if there is no space to close, consolidation is essentially complete, so, yes, you technically skip this stage in those situations.

What are the things to look for in the prefinishing check list?

Prefinishing Checklist

Name _________________________ Date ___________

Initial bracketing date ____________

1. Goals of treatment
a. _________________________ accomplished yes ___ no ___
b. _________________________ accomplished yes ___ no ___
c. _________________________ accomplished yes ___ no ___
d. _________________________ accomplished yes ___ no ___

Explanation of no answers

2. Static Occlusion – 6 keys
a. molar relationship......acceptable yes ___ no ___
b. tip.....................acceptable yes ___ no ___
c. torque..................acceptable yes ___ no ___
d. rotations...............acceptable yes ___ no ___
e. spaces..................acceptable yes ___ no ___
f. curve of Spee...........acceptable yes ___ no ___

Explanation of no answers

3. Functional occlusion
a. Left lateral working ______ balancing interferences ___________
b. Right lateral working _____ balancing interferences ___________
c. Protrusive ______________ interferences ___________________

Is functional occlusion acceptable yes ___ no ___ CR = CO? yes ___ no ___
Equilibration required yes ___ no ___
If unacceptable, why? _____________________________________________

Ready for de-banding? Yes ___ no ___
If no, how long? ______________
Fee paid yes ___ no ___
If not, how much is owed? ____________

I have some anterior open bite cases I'm treating. In some of these cases the bite closes by just going through the wire progression while others require 019x025 nitinol rocking chair curve (RCS wire) coupled with heavy elastics from upper to lower canines. The problem with this is patient cooperation; patients will not apply the heavy anterior elastics because they hurt and instead of closing anterior bite we now have more bite opening. So, I'm wondering instead of using the RCS wire maybe I can use just a regular 19x25 nitinol with lighter anterior elastics (1 or 2 elastics instead of 3) . So, if the patient doesn’t wear the elastics the open bite won’t worsen. Would this work? What do you think?

Welcome to the wonderful world of ortho. One of the advantages of GP ortho is you get to pick the cases you want (and don't want) to treat. With diagnostic experience comes the ability to pick out these tougher cases before you begin treatment. You can then either charge more or refer.
If you have an open bite in the bicuspid area as well as in the anterior, a flat wire will not easily solve the entire open bite problem. In these cases, there is no way around the difficult mechanics of RCS plus heavy elastics. However, if the bite is closed (or nearly closed) in the bicuspid area, then lighter anterior elastics on a wire without curve should do the job.

Remember, a little (1 to 1.5mm) lateral open bite may respond to differential bracket position. Get those bis bracketed gingivally, and eruption (and hence lateral open bite closure) may occur. That being said, RCS plus heavy elastics is still one of the most reliable methods of open bite closure.

Wednesday, May 20, 2009

Frequently asked questions

In space closure, if after a couple of months of space closure, we still have a couple of mm of space in the upper anteriors and no spacing in the lower arch, the occlusion is a solid ClassI with little or no overjet, is it correct to assume that we have a tooth size discrepancy? There seems to be 2 ways to deal with this remaining space, either bond composite to the upper teeth to close it or perform ARS on the lowers? What would you do in this situation?

Studies show that in 60% of cases, there is a tooth size discrepancy where there is more tooth mass on the lower arch than on the upper. This is usually due to small upper laterals or large lower laterals. We call this the 60% problem. The solution to this is to do what you suggest. In 20% of all cases, there is excess tooth mass on the upper. This is called the 20% problem; it can also be corrected by IPR, but in this situation, it is the upper arch that is reduced. In my practice, I often do the ARS on the premolars because stripping in that area does not affect the esthetics as much.
The interesting point about this discussion is that only 20% of all cases have no tooth size- arch length discrepancy, so the problem you describe is present in a lot of cases. However, in many cases with a discrepancy the problem is too small to be clinically relevant, so not all of the cases with a discrepancy need interproximal tooth reduction or bonding.

If we are to call the diagnostic arch length the existing mandibular form, taken from the molar buccal cusp tips and anterior incisal edges, and not expand, how do we substantial crowding?
Another way to put my question-when we unwind all of the crowding, don't we need a longer arch length, or distal drive the molars? Creating a Roman arch form and advancing anteriors will not strictly maintain this existing arch length, right?

If you keep your arch length the same, the only way you can relieve crowding is to remove tooth structure. Tweed wrestled with this problem 70 years ago and ended up extracting 4 bis in 90% of his cases.
We base our arch width on a line 3mm wider than the cusp tips/incisal edges to account for bracket thickness. We can change arch form (expand or labially advance teeth) to relieve crowding. How much of this can you do? Different practitioners will alter arch form different amounts. The more you change arch form, the less stable the final result will be, but the more you alter arch form, the less extractions you have to do.
From a philosophical standpoint, I am not a big fan of distalization, especially on the lower. I don't like pre-determined arch forms, and I don't like to do a lot of expansion. This is why I extract teeth. Over the last 15 years, I extracted some combination of bicuspids in a little over 21% of my cases. This is a little bit lower than the 26% national average as reported by the AAO, but as a GP doing ortho, I do refer some of the more difficult cases that present in my office. These difficult cases are usually extraction cases, so factoring in these cases to my overall percentage would bring my extraction percentage closer to the national average.

I have evaluated cases involving Class II elastics and I remember what you said about the use of Class II elastics,that is, Class II elastics really work but if you use them you may be "selling your soul because of some of the side effects that may occur”. I've looked at a few of my cases and I think you meant Class II elastics may distort everything we've worked to achieve up to this point in treatment. I see mostly lateral open bites, especially molars out of occlusion. So what should or could we do to remedy the ill effects of Class II elastics? Do we use single elastics on each side and use less aggressive means (I've been using 2 elastics on each side 3/16 med full time wear)? Do we accept this problem as side effects of Class II elastics and deal with it after the Class II has been corrected? I'm thinking using Class II finishing elastics with vertical elastics on the 6's or maybe even bracketing the 7's. What are your thoughts on this matter?

There are certainly many side effects associated with Class II elastics. To minimize the side effects, I try to use them only in .019x.025 st steel with the bite opened to the desired level. Then,the elastics act as minor repositioning devices. This, hopefully, will eliminate the lateral open bite problem. If lateral open bite still occurs, go to a lighter wire after the Class II is corrected and the occlusion should settle.
I like to use ¼” medium elastics, with full time wear. This provides a constant repositioning force and maximizes the speed of correction. If correction doesn’t occur with this force, I increase the force by using 2 elastics per side, but this may lead to the side effects you described, especially in weak muscled patients. Vertical finishing elastics are a good way to close lateral open bites; bracketing the 7’s in cases that can tolerate the bite opening will also help.
The bottom line is Class II elastics are a good way to correct Class II, IF you can stand the side effects. Many ways exist to handle the side effects, but these ways may be a bit mechanically complex.

I noticed that a case of mine has a tooth size discrepancy, with wide mand lateral incisors, and wide mand second bi's. Much more crowing exists on the lower than the upper, and the molars are Class I, but with only 2 mm of overjet in the anteriors. Initial leveling and aligning will probably advance the lower anteriors. Do we wait to do IPR on these type of cases after crowding and rotations are relieved, or can do IPR before initial aligning? She is not a weak muscled patient, but I still would prefer not creating edge to edge in anteriors and opening the bite. But I guess that it comes with the territory that the teeth may look worse before they look better.

Good job in picking out the tooth size discrepancy before treatment starts. I like to align before I do IPR, even if it means the occlusion will be edge to edge for awhile. The reason I do it this way is because when the teeth are aligned, it is easier to strip the contact points and shape the teeth correctly. When crowding exists it is tough to get at the contact points accurately. In addition you never quite know how the leveling and aligning will play out, so I always like to get things lined up before I do something irreversible. So, get into at least .016st steel before doing any reduction.

Temporary Anchoring Devices or mini implants are something we've never talked about. They are gaining in popularity among orthodontists. Are you currently using them? Do you think this will decrease treatment time? What kind of cases are they indicated, deep bites cases, open bite cases ?
What are your feelings towards TAD?

TAD's are all the rage these days. They are easy to insert and remove and provide reliable anchorage. They are used for space closure, distalization, intrusion, as well as attachment points for interarch elastics so the mechanical advantage of the elastics is greater. They are often used for bite opening and bite closing. I see their use greatly increasing over the next few years.