What should be corrected first- overjet, overbite, or midline discrepancies? Do you correct one at a time or all at the same time?
Answer:
1) Always correct overbite before overjet. Overbite is corrected during the wire progression (.014,.016, and .020 stainless steel). Use curve if the pre-treatment overbite is 6mm or greater.
2) Overjet, midline correction, space closure, and other aspects of the malocclusion (except for overbite, which is done earlier) are corrected in the mechanics phase- after the wire progression. Correct these aspects of the malocclusion in .019x.025 stainless steel, because this wire provides very good control. By following these guidelines, most malocclusions can be corrected efficiently.
I have created enough space by using coil springs and have engaged the crowded teeth. I have used .016 Niti for 3 weeks since coil springs were removed. The lower centrals have flared excessively. This concerns me. I have used .016 Niti for 5 months. Is this too long? Also, should I be doing anything at this point the get those lower centrals back where they belong? How do I do this? Do I use power chain?
Answer:
You were probably a little too aggressive in your use of coil springs; that is, the coil springs you used may have been a little long. Short term excessive flaring of the lower incisors is usually not a problem, unless anterior gingival recession occurs. If recession has occured, use chain to retract the anteriors. If no recession is apparent, align the incisors (remember to use steel ties if the wire is not fitting passively into the slot when you are using .016 niti), then begin the wire progression. The incisors may settle back on their own. Don't use chain until you are in a much heavier wire (.019x.025 stainless steel is best) because the force levels exerted by chain are very high. Five months is not too long to be in .016niti- a mistake I often see is doctors progress out of niti too quickly. Remember, open coil spring is used to tease the teeth apart; you don't need to pack a lot of coil to gain space. As a general rule, the coil is 2mm longer than the distance between the adjacent brackets. Every month, use a spring that is 2mm longer than the coil used in the previous month. Discontinue coil and engage the tooth when there is enough space in the arch to fit the previously blocked out tooth.
After using 016 niti for 6 months, I started a wire progression on a 13 yr old patient. Everything looks OK on the upper (coil springs to create space). But the lower left lateral, even after all this time, still is rotated. Additionally about 1.5 mm of crowding still exists. I was not sure what to do, so I started a wire progression (.014 ss). The wire is slightly kinked in (I had to push it slightly to fit into the bracket slot). I know that the wire has to be passive to maintain arch integrity. As of now, the crowding will not allow the LL2 to fit in the arch. Did I not create enough space with the open coil? Should I have done IPR before progressing to 014ss? Did I progress to .014stainless steel prematurely? Could I pack coil later, say in .020 stainless steel, and create space? Does this method create space too late? Is it as efficient as creating space in .016 niti?
Answer:
If, as you say, there is still 1.5mm crowding, you have not yet created enough space to bring this tooth into the arch. Use coil to gain more space. Rotations are nearly impossible to correct if there is not enough space in the arch. If there is enough space, it is much easier to engage the tooth with niti. Then the correction of the rotation will proceed uneventfully.
Many doctors will progress up a wire progression, bypassing severely rotated teeth. Once they get to a heavier wire (.016 stainless steel or heavier), they will pack coil a little more aggressively to create enough space for the rotated tooth. Then after enough space is created they will step back to niti and engage the rotated tooth. This method results in less arch distortion, but it takes a little longer. You never want to kink a stainless steel wire. It will not return to its original shape so it will not move the teeth efficiently.
IPR is an option in this case. If the tooth is thinner, it will fit into a smaller space. The problem with IPR on rotated teeth is the inability to access the contact point, which is the area where you want to do IPR. So do the IPR only after space is created and you can get at the contact point.
After full banding, can we give the patient a bite plane until an anterior crossbite is corrected, or is it OK just to let the braces move the teeth?
Answer:
In general terms, a bite plane will, because it eliminates interferences, allow the teeth to move more quickly. In my experience, patients in braces don't wear bite planes very well. The teeth move a little, and, as a result, the bite plane doesn't fit. That being said, a lot of orthodontists use bite planes. I prefer to open the bite by bonding composite to the occlusal surface of the lower molars. The bonding can be done quickly, it is not removable by the patient, and it is easily removed by the doctor after the occlusion improves. Kids tolerate the change in occlusion well, but adults hate it. So I'm a bit more discriminating when I'm considering this on adult patients.
I've been putting second molar brackets on my patients, and find that they report a lot of soft tissue irritation. I know about using ortho wax, and I always encourage patients to use it to intercept problems before irritation occurs. Do you have soft tissue problems with second molar brackets, and do you use the smaller ones, or the larger first molar brackets to get more surface area for bonding?
Answer:
I usually use the smaller bracket because of irritation issues. Remember, on the upper it's OK to use 1st and 2nd molar brackets interchangeably, but on the lower it is not. The prescription is different on the lower 1st and 2nd molars-more lingual crown torque is present in the lower 2nd molar brackets than the lower 1st molar brackets.
How do I change the molar relationship from a full cusp (8mm) ClassII relationship to a ClassI molar relationship in a non-growing patient?
Answer:
In a non-growing patient, it is very difficult to change a full cusp (8mm) Class II molar relationship to ClassI molar relationship. So most of the time we don’t try (don't fight molar relationship, especially in non-growers, is a statement with which most orthodontists would strongly agree). Usually in these kinds of cases, keep the molars in ClassII. Do this by taking out only the upper 1st bicuspids and retracting the anterior segment. The molars stay in ClassII, but the canines end up in ClassI and the overjet is corrected. Typically in these cases, the upper anteriors are protrusive, so taking out upper bicuspids provides space for retraction of the upper anteriors. Often, problems arise with these cases if the bite is deep. It is more difficult to open the bite in extraction cases than in non-extraction cases.
Anchorage control is very important in upper bicuspid extraction cases. The molar relationship is ClassII, so additional mesial movement of the upper molars is contraindicated. In addition to lacebacks in the initial stage of treatment, some method to prevent this forward upper molar movement must be used during space closure. Trans-Palatal Arches, Nance buttons, headgear, and banding or bonding the upper 2nd molars are all treatment modalities that are used to increase posterior anchorage during space closure.
What do you use to rotate a tooth? Recently, I bought some rotation wedges. Do you recommend using these and how do you use them?
Answer:
I'm not a fan of rotation wedges. They are tough to put in and they don't stay in very well.I prefer to create space with coil, then after space is created, while still using a flexible arch wire such as .016niti, tie the tooth in tightly with a steel tie.
I have a case where tooth #7 was in lingual cross-bite. I brought the crown into the arch, but the root did not translate- that is,the root is still facially inclined. First, I repositioned the bracket several times and I placed a .016x.022 stainless steel wire, but the lingual root torque has not occurred. How do I correct the root torque? I think some doctors place the lateral brackets upside down in these situations. I did that for a few months in the .016 niti, but the root just did not move lingually. This is very frustrating. Do you have any thoughts on this?
Answer:
You need lingual root torque on the lateral. The lateral incisor bracket that I use has 10 degrees of labial crown torque (which is the same as -10 degrees of lingual root torque) so the bracket will not move a root lingually very easily (the bracket prescription does not encourage lingual root movement). If you put the lateral bracket on upside down, the torque changes to -10 degrees, which results in a situation that encourages lingual root movement. Remember, for torque to be expressed, you must use a rectangular wire. You cannot torque teeth on a round wire. Even a .016x.022 does not fill the slot enough to affect torque very quickly. Get into .019x.025 (preferably stainless steel) and torque will be expressed.
I have a patient that started with 7mm of overbite. I curved the upper wires, and the bite has not opened enough. Should I use .016x.022 rectangular wire with curve?
Answer:
As a rule, I don't like to curve rectangular wire. If the bite needs further opening, try curving the .020st steel a little more, and use .020 stainless steel with a little deeper curve on the lower as well. Stubborn deep bites are the result of an incomplete leveling of the curve of Spee. Lower curves will solve this. If, after a couple of months, the bite is not open, bracket the 7's (I usually direct bond them). Erupting 2nd molars often is the best way to get the bite opened. A word of advice: do not do any other mechanics until the bite is opened. Do what it takes (and be patient!) to get the bite opened before progressing in the case. You will save a ton of time in the long run.
Wednesday, August 26, 2009
Saturday, August 8, 2009
Still More Questions
I'm treating a 12 yr old female with mild crowding, ClassI dental and skeletal, deep overbite, some rotations, and a low mandibular plane angle. I've bracketed and banded, with differential bracket placement, and propped the bite open slightly with composite on the occlusal surface of the lower molars to accommodate the mandibular brackets. I’ve used 016 Niti for a couple of months. Now I notice the second molars are in crossbite. Do I bracket these now or wait? Any problems with merely bracketing these 7s at the next appointment? Or should I make some type of temporary bite plate to unlock the occlusion while I move them?
I would bracket the 7's asap, because not much will happen as far as correction of the deep bite/crossbite until you have control of the 7's. This happens a lot, and bracketing the 7's will solve the problem. There are no problems with waiting a month, but you are just not making any progress toward finishing if you don't bracket.
I have a question regarding differential bracket placement. I noticed that there is a line in McLaughlin's book outlining this, but in general he does not routinely use this procedure. Don't we want the brackets to be placed ideally relative to the incisal edge at the end of treatment to achieve a flat curve of Spee and ideal marginal ridge alignment? His technique seems to imply that ideal placement will usually flatten the curve and open the bite appropriately by that procedure only, perhaps followed by reverse curve in rectangular ss if needed. Is there a disadvantage to placing brackets differentially at the start of treatment?
McLaughlin does not use differential bracket positioning as much as I do. However, the last time I saw him speak (18 mo ago) he said he was leaning toward more differential bracket positioning, especially in the anterior. If you wait long enough, a flat wire with ideal bracket position will level the curve. In strong muscled patients, this may take a long time. I don't like curving rectangular wire (this does level the curve very quickly) because of the side-effects it produces.
I have found no disadvantages to differential bracket positioning. I continue to use this technique as I have for the last 20-plus years. In fact, I probably place my anterior brackets a little incisally on most cases, even those that do not require bite opening. My bias toward incisal anterior bracket positioning is due to the fact that the more incisally the bracket is placed, the more torque (positive labio-lingual inclination) is expressed. Since torque expression is the "weak link" of the pre-adjusted appliance, this incisal bias results in helping solve the most difficult problem (torque expression) in using the pre-adjusted appliance.
I heard a comment at a seminar regarding "round tripping”. I'm thinking that I should have used more bendbacks to inhibit the mandibular incisors from flaring forward. Do bendbacks inhibit open bites and excessive anterior flaring? If we want to control the mandibular arch length and shape, maybe bendbacks are appropriate. McLaughlin mentions bendbacks, and also mentions IPR. Perhaps he is thinking about preventing flaring of the mandibular incisors.
If we do bendbacks, how do we correct rotations and crowding especially if we use open coil springs? The space has to be gained somewhere! Maybe he's doing an arch length analysis, then IPR immediately in non-extraction cases, rather than gaining space through anterior tipping of the incisors, unless a more protrusive appearance is called for. You have said that you like to be in control. Maybe I need to control this incisor position more effectively, particularly in the mandibular arch during the first step. But how is this done?
When you treat a case non-extraction, you must be willing to accept the fact that to unravel the crowding, the teeth will move forward. If you don't want the teeth to move forward, then you must gain some space some way- stripping, extraction, expansion and/or distalization. Each of these modalities has problems associated with it. Moving teeth forward to unravel crowding is not round tripping, because, if the diagnosis is correct, you will not plan on moving the teeth back to their original position.
The big issue is diagnosis-where will the teeth end up with the plan you choose and is this right for the patient? There are many ways to get the teeth where you want to get them, but figuring out where they belong is the most important part.
I just started a case with an RPE. Last week the appliance fell out and the patient waited a couple of days to come in the office. I had a very difficult time recementing the appliance. Is this due to relapse? Patient activated appliance for 2 weeks and it is now passive. The appliance may fall out again. What should I do in this situation?
If you can' t get the appliance to fit well, first determine if the problem is lack of space for the molar bands. You could try placing spacers for a day or so before attempting recementation. If the actual expansion relapsed, turn the screw backwards for a couple of turns, then recement. If you are satisfied with the amount of expansion you currently have, make a Hawley retainer. Have the patient wear it full time for a few months. Then, bracket as usual.
I have a question regarding reverse and compensating curve. I placed curve in the maxillary arch. A month later, after I took out the 014ss there was no curve on the wire. Does the curve disappear after a month? Is there supposed to still be a curve after I take it out? There is a small space between 8 and 9; I take it that is from the flaring so I assume that the curve did do something. I tried to think back to your lectures but could not remember if you mentioned what the wire would look like after removing it.
Often the lighter wires will straighten out a little because they are held in a straight position (tied in) for a month. I would be more concerned with results- reduction of overbite- than how the wire looks when it is removed. That being said, the biggest problem most doctors have when using curve is they don't put enough curve into the wires, especially the lighter wires. Bottom line- what you have is probably OK. Just make sure you curve the .014's enough.
I'm working on a 4-bi extraction case. One of the max 2nd molars is partially buried with a 45% angle to the distal of the first molar. Do I attempt to bracket this now, and upright with Niti, or wait until space closure? Should I use another uprighting procedure? Will this issue resolve itself with slight mesial movement of the molar during space closure?
If the case is moderate anchorage, close the extraction space and the space gained in the posterior will allow for eruption. If it needs to be aligned, bracket the 7 during finishing.
I would bracket the 7's asap, because not much will happen as far as correction of the deep bite/crossbite until you have control of the 7's. This happens a lot, and bracketing the 7's will solve the problem. There are no problems with waiting a month, but you are just not making any progress toward finishing if you don't bracket.
I have a question regarding differential bracket placement. I noticed that there is a line in McLaughlin's book outlining this, but in general he does not routinely use this procedure. Don't we want the brackets to be placed ideally relative to the incisal edge at the end of treatment to achieve a flat curve of Spee and ideal marginal ridge alignment? His technique seems to imply that ideal placement will usually flatten the curve and open the bite appropriately by that procedure only, perhaps followed by reverse curve in rectangular ss if needed. Is there a disadvantage to placing brackets differentially at the start of treatment?
McLaughlin does not use differential bracket positioning as much as I do. However, the last time I saw him speak (18 mo ago) he said he was leaning toward more differential bracket positioning, especially in the anterior. If you wait long enough, a flat wire with ideal bracket position will level the curve. In strong muscled patients, this may take a long time. I don't like curving rectangular wire (this does level the curve very quickly) because of the side-effects it produces.
I have found no disadvantages to differential bracket positioning. I continue to use this technique as I have for the last 20-plus years. In fact, I probably place my anterior brackets a little incisally on most cases, even those that do not require bite opening. My bias toward incisal anterior bracket positioning is due to the fact that the more incisally the bracket is placed, the more torque (positive labio-lingual inclination) is expressed. Since torque expression is the "weak link" of the pre-adjusted appliance, this incisal bias results in helping solve the most difficult problem (torque expression) in using the pre-adjusted appliance.
I heard a comment at a seminar regarding "round tripping”. I'm thinking that I should have used more bendbacks to inhibit the mandibular incisors from flaring forward. Do bendbacks inhibit open bites and excessive anterior flaring? If we want to control the mandibular arch length and shape, maybe bendbacks are appropriate. McLaughlin mentions bendbacks, and also mentions IPR. Perhaps he is thinking about preventing flaring of the mandibular incisors.
If we do bendbacks, how do we correct rotations and crowding especially if we use open coil springs? The space has to be gained somewhere! Maybe he's doing an arch length analysis, then IPR immediately in non-extraction cases, rather than gaining space through anterior tipping of the incisors, unless a more protrusive appearance is called for. You have said that you like to be in control. Maybe I need to control this incisor position more effectively, particularly in the mandibular arch during the first step. But how is this done?
When you treat a case non-extraction, you must be willing to accept the fact that to unravel the crowding, the teeth will move forward. If you don't want the teeth to move forward, then you must gain some space some way- stripping, extraction, expansion and/or distalization. Each of these modalities has problems associated with it. Moving teeth forward to unravel crowding is not round tripping, because, if the diagnosis is correct, you will not plan on moving the teeth back to their original position.
The big issue is diagnosis-where will the teeth end up with the plan you choose and is this right for the patient? There are many ways to get the teeth where you want to get them, but figuring out where they belong is the most important part.
I just started a case with an RPE. Last week the appliance fell out and the patient waited a couple of days to come in the office. I had a very difficult time recementing the appliance. Is this due to relapse? Patient activated appliance for 2 weeks and it is now passive. The appliance may fall out again. What should I do in this situation?
If you can' t get the appliance to fit well, first determine if the problem is lack of space for the molar bands. You could try placing spacers for a day or so before attempting recementation. If the actual expansion relapsed, turn the screw backwards for a couple of turns, then recement. If you are satisfied with the amount of expansion you currently have, make a Hawley retainer. Have the patient wear it full time for a few months. Then, bracket as usual.
I have a question regarding reverse and compensating curve. I placed curve in the maxillary arch. A month later, after I took out the 014ss there was no curve on the wire. Does the curve disappear after a month? Is there supposed to still be a curve after I take it out? There is a small space between 8 and 9; I take it that is from the flaring so I assume that the curve did do something. I tried to think back to your lectures but could not remember if you mentioned what the wire would look like after removing it.
Often the lighter wires will straighten out a little because they are held in a straight position (tied in) for a month. I would be more concerned with results- reduction of overbite- than how the wire looks when it is removed. That being said, the biggest problem most doctors have when using curve is they don't put enough curve into the wires, especially the lighter wires. Bottom line- what you have is probably OK. Just make sure you curve the .014's enough.
I'm working on a 4-bi extraction case. One of the max 2nd molars is partially buried with a 45% angle to the distal of the first molar. Do I attempt to bracket this now, and upright with Niti, or wait until space closure? Should I use another uprighting procedure? Will this issue resolve itself with slight mesial movement of the molar during space closure?
If the case is moderate anchorage, close the extraction space and the space gained in the posterior will allow for eruption. If it needs to be aligned, bracket the 7 during finishing.
I have a question regarding intraoral elastics. For Class II correction, what size do you usually use?
I most often use 1/4" medium, 1 elastic per side, full time wear, patient changes elastics every 12hrs, and eating with them in is optional.
When is the correct time to start the wire progression? What if brackets are improperly positioned? Do you reposition brackets before starting the wire progression?
Begin the wire progression when the niti arch wire fits passively into all slots. If brackets are improperly positioned, don't worry yet. You will reposition after a few months of wire progression. Your goal is to progress to larger arch wires. When the bracket slot is full (or nearly full), you will be able to see malpositioned brackets. It is much more efficient to reposition all brackets that need it at once, rather than doing one now, one next month, etc.
I find that I'm spending a lot of time coordinating .019x.025 st. steel. When I try to conform the 19x25 st. steel to my initial wire I use my fingers to shape it. Do you use pliers to do this? Because I am having a hard time accurately coordinating these wires, on one case I elected to leave the 19x25 niti in for the mechanics phase. If I do use 19x25 niti instead of the steel how long should I use it? If the 19x25 niti fits passively after 2 to 4 months, is that a sign that it has served its purpose?
I coordinate .019x.025 st steel with hollow chop pliers. (In the Ortho Organizers cat. it is Endura Pliers #201-401) It is tough coordinating these, but with practice, it can be done.
Often, I don't progress to rectangular stainless steel when there are no mechanics to do. If, for example, there is no space closure, midline shift, or Class II or Class III correction to do, I often skip the .019x.025 st steel and stay in .019x.025 niti. This has to stay in about 3 months to provide torque expression. When it is passive, it has done its job. However, don't get into the habit of doing complex mechanics on niti, because the side-effects of these mechanics are more easily expressed on the low-load deflection archwires.
Wednesday, June 17, 2009
More Questions
I want to ask you how to correct a bilateral crossbite in a 42 year-old patient. I do not think I can use a palatal expander. Is there any way to correct it?
These situations are tough. You can't split the palate without surgery; the sutures are too mature. That leaves us with tipping teeth. You can probably get about 3mm per side of expansion by tipping. If the amount of crossbite is 2mm or less, expanding the archwires during the wire progression may do the trick. If the amount of crossbite is approaching 3mm, a Schwarz plate (which I personally don't like to use) or a quad helix (which I like) will get you to your goal. In any adult crossbite case, always consider leaving the patient in crossbite. Sometimes the best answer is the most simple.
One other question: I have some patients' moms discussing ortho in their young kids, who still have many deciduous teeth. Is it usually best to wait until these have exfoliated? I understand that growth curves favor early intervention, but waiting for permanent bis to erupt may prolong treatment. Do orthodontists routinely wait for all the deciduous molars to exfoliate prior to starting ortho? Are there certain malocclusions that most practitioners treat early?
You are touching on a very controversial topic. Many practitioners swear BY early treatment-they say it is always better to treat early- while many practitioners swear AT early treatment- they say it is worthless. The answer is probably somewhere in between. The more severe the malocclusion, the more early intervention seems to help. FYI, most of the orthodontic literature demonstrates there is not a whole lot of value in early (two phase) treatment as compared to more traditional single phase treatment. The bottom line is that with experience you will develop a treatment philosophy that probably will include some early treatment.
When are vertical (triangular) elastics used in the finishing phase? Would that be in weak muscled patients? Do you routinely use elastics for finishing, or mainly rely on settling forces and arch wire bends?
I use finishing elastics in about 20% of my cases. They tend to be helpful on weaker muscled patients, where the muscles are unable to provide adequate settling forces. I try bends before adding elastics in most cases. If the bends provide good interdigitation, I'm done; if not I add elastics.
I am finishing up a case in which all teeth interdigitate well with the molars in solid Class I occlusion. I had the patient use Class II elastics for 3 months. However, some overjet remains in the anterior. Since all teeth are in contact, I do not think it is a good idea to do IPR on the anterior teeth and retract them with chain elastics. I might improve the overjet, but teeth might not interdigitate well as a result. What is your call on this?
I think you are faced with a tooth size discrepancy. Upward of 80% (that's right 80%) of patients have some sort of discrepancy. This case probably has excess tooth structure in the maxillary. This often presents as good posterior interdigitation combined with overjet. In these cases I often do a little ARS in the upper. I usually strip 1mm distal to each cuspid. Then I close the space with 6-6 chain. I find that this retracts the anterior segment a bit without changing the posterior occlusion. Because the space closure is minor, it can be done on the finishing wires (.018st steel), although it is always better to close spaces on .019x.025 stainless steel wires.
I have a case in which I could not close the space of about 1 mm between the bicuspids with elastic chain. I am thinking of using closing coil; however I have never used it. I learned that there are niti and stainless steel closing coils. These coils can be purchased in spools, or in different lengths with hooks at the ends (to engage the hooks on brackets). I prefer spools of stainless steel coil. I have not ordered any and want your recommendation. Please recommend the type and the steps of how to choose the length of the coil for a particular span from one bracket's hook to another. If you happen to recommend the one that comes in a spool, please advise me how to form a "hook" at both ends of the coil, so I am able to engage it on the bracket hooks.
When I use closing coil (which is rarely), I use stainless steel coil off of a spool. I like to stretch the coil about 1.5 times its resting length measured from the distance between the two attachment points. I use a bird beak and grab the last link of the coil, turn it up 90 degrees, and shape it to make a loop at right angles to the rest of the coil. (If you experiment with this, you will find this to be very easy to do.)I then use a Koby hook on the bracket of the teeth to be engaged if it doesn't already have a hook on the bracket. Stretch the coil, and slide the loops over the hooks. Remember, any method of force application should work. I would be more inclined to look at why the space is not closing, not changing the method of space closure. Some possible culprits:
1) overbite is too deep
2)bracket position is off
3) sinus on the upper is low-cortical bone of sinus wall is interfering with root movement
4)friction in space closing set up
Usually, for the last mm or so, friction is the culprit. You could have a bracket whose tie wing is bent, a slot that is a bit constricted, or numerous other issues. I usually will try (if I have eliminated the other above possibilities)going to .020 stainless steel and closing the remaining space on round wire with chain. I know this violates one of my rules, and we are risking the expression of side-effects, but for a mm or so in a stubborn case, the risk is worth it. Remember, you have to know the rules before you can break them.
I have always bracketed all upper teeth at same height from the incisal with the cuspids and centrals .5 mm longer than the laterals. I know you position brackets by finding the center of the teeth. I am just not too comfortable at doing it your way. I read old lectures, not yours, and came across one that said to bracket all teeth at same height from the incisal with the laterals .5 mm shorter. What are your thoughts on these different ways of bracket positioning?
You are touching on the art vs. the science of orthodontics. Any consistent way to get brackets positioned properly is vital to getting a good result. Changing how brackets are positioned will give you different smile lines and esthetics. Understanding this means you are starting to understand the art of orthodontics. Positioning the anterior brackets a little incisally will result in some intrusion and, therefore, a little less tooth display than positioning the anterior brackets more gingivally. So each of these techniques may be appropriate in different situations. Incisal positioning may look a little nicer in a patient who already has excessive gingival display. Gingival positioning may be appropriate for a patient who doesn't show a lot of teeth while talking or smiling.
My point is each case is different, and if you truly want to provide the best results for your patients, you must, at times, deviate from the ideal. Understanding how different bracketing techniques result in different esthetic results will allow you to change bracket positions with confidence.
I find that I'm spending a lot of time coordinating my 19x25 stainless steel. When I try to conform the 19x25 steel to my initial wire I use my fingers to match the wire. Do you use pliers to do this? On one case I elected to leave the 19x25 niti because my steel was not accurate. If I do leave the 19x25 niti instead of the steel how long should I wait? If the 19x25 niti fits passively after 2 to 4 months is that a sign that it has served its purpose?
I coordinate .019x.025 st steel with a hollow chop pliers(in the Ortho Organizers cat. it is Endura #201-401). It is tough coordinating these, but with practice, it can be done. In some cases, I don't use .019x.025 stainless steel when there are no mechanics to do. If there is no space closure, midline shift, or Class II or Class III correction, I often skip the .019x.025 st steel and stay in .019x.025 niti. This has to stay in at least 3 months to provide torque expression. When it is passive, it has done its job. However, don't do complex mechanics on niti, because the side-effects of these mechanics are more easily expressed on the low-load deflection archwires.
Thank you for the reply, regarding the wire progression. Mechanics should not be done with any 19x25 niti wire at all? What about space closure and elastics use?
The low load deflection arch wire (niti) is not strong enough to overcome the side-effects of commonly used orthodontic mechanics. For example, if you use Class II elastics, the patient usually hooks the elastic to the hook on the lower 1st molar band. The elastic provides a vertical force on the molar. The low-load deflection niti wire will be overpowered by the elastic, resulting in extrusion of the molar. The result is loss of vertical control. If the same mechanics are done with .019x.025 stainless steel wire, the strong arch wire will prevent extrusion of the molar. The result here is better vertical control.
I have two concerns. First,I have a case which I expanded both upper and lower arches due to severe lingually inclined teeth. After the teeth are uprighted, do I need new upper and lower models to coordinate the wires? How do I coordinate arch wires, lower 3 mm wider than what is indicated on the new model and upper 3 mm wider than lower? Or do I make the lower arch width 6-7 mm wider than what is indicated on the new model,with the upper 3 mm wider than lower?
Second, you said Class II elastics will reduce about 4 mm of overjet. I'm using Class II elastics on a case that needs 8mm of Class II correction. After correcting 4 mm of overjet (I still need 4 mm more of overjet correction),can I hold the bite where it is after the first correction of 4 mm overjet for six months, to give the condyle and the fossa time for bone remodeling and muscle adaptation?. Then, after the rest period,can I use a second round of Class II elastics for the remaining 4 mm of overjet correction? I'm referring only to using Class II elastics, with no other means of Class II correction, such as extraction or ARS.
When coordinating arch wires,I look at how much expansion is needed (for this look at pre-treatment models) and coordinate all my stainless steel arch wires to this position. In the example you gave, I would not take another model just for the purpose of arch wire coordination. If my arch widths are where I want them , I simply continue to coordinate based on the pre-treatment model. Because the arch widths are correct, you are using the correct arch width coordination. There is no reason to complicate matters by changing how you are coordinating the arch wires.
I rarely use Class II elastics for more than 5mm of Class II correction, even in very strong muscled patients. The issue is not a TMJ issue-the condyle and fossa can adapt to the new condylar position. In fact, when using repositioning appliances, we expect condyle and fossa adaptation for even larger horizontal corrections. The issue is the side effects that Class II elastics cause to the occlusion. For example, if you try to correct 8mm of overjet with Class II elastics, the vertical forces placed on the lower molars will extrude them. This will result in occlusal plane tipping and downward and backward rotation of the mandible, tipping of the upper occlusal plane inferiorly in the anterior, which results in increased gingival display. A rest phase does not change the total time you need to use Class II elastics; the net side effects will still be there.
The bottom line is this: Class II elastics are very effective in correcting small and moderate amounts of Class II, especially in strong muscled patients. But, the side effects are real, and can ruin an otherwise nice result. Don't fall into the trap of using Class II elastics in severe Class II situations in an effort to avoid more difficult treatment options that may be better for the patient. Be aware of potential side effects, and understand which patients will not respond well to the elastics. Also understand what specific side effects will be detrimental to the patient that is being treated with Class II elastics, and watch carefully for the first signs of the particular side effects.
These situations are tough. You can't split the palate without surgery; the sutures are too mature. That leaves us with tipping teeth. You can probably get about 3mm per side of expansion by tipping. If the amount of crossbite is 2mm or less, expanding the archwires during the wire progression may do the trick. If the amount of crossbite is approaching 3mm, a Schwarz plate (which I personally don't like to use) or a quad helix (which I like) will get you to your goal. In any adult crossbite case, always consider leaving the patient in crossbite. Sometimes the best answer is the most simple.
One other question: I have some patients' moms discussing ortho in their young kids, who still have many deciduous teeth. Is it usually best to wait until these have exfoliated? I understand that growth curves favor early intervention, but waiting for permanent bis to erupt may prolong treatment. Do orthodontists routinely wait for all the deciduous molars to exfoliate prior to starting ortho? Are there certain malocclusions that most practitioners treat early?
You are touching on a very controversial topic. Many practitioners swear BY early treatment-they say it is always better to treat early- while many practitioners swear AT early treatment- they say it is worthless. The answer is probably somewhere in between. The more severe the malocclusion, the more early intervention seems to help. FYI, most of the orthodontic literature demonstrates there is not a whole lot of value in early (two phase) treatment as compared to more traditional single phase treatment. The bottom line is that with experience you will develop a treatment philosophy that probably will include some early treatment.
When are vertical (triangular) elastics used in the finishing phase? Would that be in weak muscled patients? Do you routinely use elastics for finishing, or mainly rely on settling forces and arch wire bends?
I use finishing elastics in about 20% of my cases. They tend to be helpful on weaker muscled patients, where the muscles are unable to provide adequate settling forces. I try bends before adding elastics in most cases. If the bends provide good interdigitation, I'm done; if not I add elastics.
I am finishing up a case in which all teeth interdigitate well with the molars in solid Class I occlusion. I had the patient use Class II elastics for 3 months. However, some overjet remains in the anterior. Since all teeth are in contact, I do not think it is a good idea to do IPR on the anterior teeth and retract them with chain elastics. I might improve the overjet, but teeth might not interdigitate well as a result. What is your call on this?
I think you are faced with a tooth size discrepancy. Upward of 80% (that's right 80%) of patients have some sort of discrepancy. This case probably has excess tooth structure in the maxillary. This often presents as good posterior interdigitation combined with overjet. In these cases I often do a little ARS in the upper. I usually strip 1mm distal to each cuspid. Then I close the space with 6-6 chain. I find that this retracts the anterior segment a bit without changing the posterior occlusion. Because the space closure is minor, it can be done on the finishing wires (.018st steel), although it is always better to close spaces on .019x.025 stainless steel wires.
I have a case in which I could not close the space of about 1 mm between the bicuspids with elastic chain. I am thinking of using closing coil; however I have never used it. I learned that there are niti and stainless steel closing coils. These coils can be purchased in spools, or in different lengths with hooks at the ends (to engage the hooks on brackets). I prefer spools of stainless steel coil. I have not ordered any and want your recommendation. Please recommend the type and the steps of how to choose the length of the coil for a particular span from one bracket's hook to another. If you happen to recommend the one that comes in a spool, please advise me how to form a "hook" at both ends of the coil, so I am able to engage it on the bracket hooks.
When I use closing coil (which is rarely), I use stainless steel coil off of a spool. I like to stretch the coil about 1.5 times its resting length measured from the distance between the two attachment points. I use a bird beak and grab the last link of the coil, turn it up 90 degrees, and shape it to make a loop at right angles to the rest of the coil. (If you experiment with this, you will find this to be very easy to do.)I then use a Koby hook on the bracket of the teeth to be engaged if it doesn't already have a hook on the bracket. Stretch the coil, and slide the loops over the hooks. Remember, any method of force application should work. I would be more inclined to look at why the space is not closing, not changing the method of space closure. Some possible culprits:
1) overbite is too deep
2)bracket position is off
3) sinus on the upper is low-cortical bone of sinus wall is interfering with root movement
4)friction in space closing set up
Usually, for the last mm or so, friction is the culprit. You could have a bracket whose tie wing is bent, a slot that is a bit constricted, or numerous other issues. I usually will try (if I have eliminated the other above possibilities)going to .020 stainless steel and closing the remaining space on round wire with chain. I know this violates one of my rules, and we are risking the expression of side-effects, but for a mm or so in a stubborn case, the risk is worth it. Remember, you have to know the rules before you can break them.
I have always bracketed all upper teeth at same height from the incisal with the cuspids and centrals .5 mm longer than the laterals. I know you position brackets by finding the center of the teeth. I am just not too comfortable at doing it your way. I read old lectures, not yours, and came across one that said to bracket all teeth at same height from the incisal with the laterals .5 mm shorter. What are your thoughts on these different ways of bracket positioning?
You are touching on the art vs. the science of orthodontics. Any consistent way to get brackets positioned properly is vital to getting a good result. Changing how brackets are positioned will give you different smile lines and esthetics. Understanding this means you are starting to understand the art of orthodontics. Positioning the anterior brackets a little incisally will result in some intrusion and, therefore, a little less tooth display than positioning the anterior brackets more gingivally. So each of these techniques may be appropriate in different situations. Incisal positioning may look a little nicer in a patient who already has excessive gingival display. Gingival positioning may be appropriate for a patient who doesn't show a lot of teeth while talking or smiling.
My point is each case is different, and if you truly want to provide the best results for your patients, you must, at times, deviate from the ideal. Understanding how different bracketing techniques result in different esthetic results will allow you to change bracket positions with confidence.
I find that I'm spending a lot of time coordinating my 19x25 stainless steel. When I try to conform the 19x25 steel to my initial wire I use my fingers to match the wire. Do you use pliers to do this? On one case I elected to leave the 19x25 niti because my steel was not accurate. If I do leave the 19x25 niti instead of the steel how long should I wait? If the 19x25 niti fits passively after 2 to 4 months is that a sign that it has served its purpose?
I coordinate .019x.025 st steel with a hollow chop pliers(in the Ortho Organizers cat. it is Endura #201-401). It is tough coordinating these, but with practice, it can be done. In some cases, I don't use .019x.025 stainless steel when there are no mechanics to do. If there is no space closure, midline shift, or Class II or Class III correction, I often skip the .019x.025 st steel and stay in .019x.025 niti. This has to stay in at least 3 months to provide torque expression. When it is passive, it has done its job. However, don't do complex mechanics on niti, because the side-effects of these mechanics are more easily expressed on the low-load deflection archwires.
Thank you for the reply, regarding the wire progression. Mechanics should not be done with any 19x25 niti wire at all? What about space closure and elastics use?
The low load deflection arch wire (niti) is not strong enough to overcome the side-effects of commonly used orthodontic mechanics. For example, if you use Class II elastics, the patient usually hooks the elastic to the hook on the lower 1st molar band. The elastic provides a vertical force on the molar. The low-load deflection niti wire will be overpowered by the elastic, resulting in extrusion of the molar. The result is loss of vertical control. If the same mechanics are done with .019x.025 stainless steel wire, the strong arch wire will prevent extrusion of the molar. The result here is better vertical control.
I have two concerns. First,I have a case which I expanded both upper and lower arches due to severe lingually inclined teeth. After the teeth are uprighted, do I need new upper and lower models to coordinate the wires? How do I coordinate arch wires, lower 3 mm wider than what is indicated on the new model and upper 3 mm wider than lower? Or do I make the lower arch width 6-7 mm wider than what is indicated on the new model,with the upper 3 mm wider than lower?
Second, you said Class II elastics will reduce about 4 mm of overjet. I'm using Class II elastics on a case that needs 8mm of Class II correction. After correcting 4 mm of overjet (I still need 4 mm more of overjet correction),can I hold the bite where it is after the first correction of 4 mm overjet for six months, to give the condyle and the fossa time for bone remodeling and muscle adaptation?. Then, after the rest period,can I use a second round of Class II elastics for the remaining 4 mm of overjet correction? I'm referring only to using Class II elastics, with no other means of Class II correction, such as extraction or ARS.
When coordinating arch wires,I look at how much expansion is needed (for this look at pre-treatment models) and coordinate all my stainless steel arch wires to this position. In the example you gave, I would not take another model just for the purpose of arch wire coordination. If my arch widths are where I want them , I simply continue to coordinate based on the pre-treatment model. Because the arch widths are correct, you are using the correct arch width coordination. There is no reason to complicate matters by changing how you are coordinating the arch wires.
I rarely use Class II elastics for more than 5mm of Class II correction, even in very strong muscled patients. The issue is not a TMJ issue-the condyle and fossa can adapt to the new condylar position. In fact, when using repositioning appliances, we expect condyle and fossa adaptation for even larger horizontal corrections. The issue is the side effects that Class II elastics cause to the occlusion. For example, if you try to correct 8mm of overjet with Class II elastics, the vertical forces placed on the lower molars will extrude them. This will result in occlusal plane tipping and downward and backward rotation of the mandible, tipping of the upper occlusal plane inferiorly in the anterior, which results in increased gingival display. A rest phase does not change the total time you need to use Class II elastics; the net side effects will still be there.
The bottom line is this: Class II elastics are very effective in correcting small and moderate amounts of Class II, especially in strong muscled patients. But, the side effects are real, and can ruin an otherwise nice result. Don't fall into the trap of using Class II elastics in severe Class II situations in an effort to avoid more difficult treatment options that may be better for the patient. Be aware of potential side effects, and understand which patients will not respond well to the elastics. Also understand what specific side effects will be detrimental to the patient that is being treated with Class II elastics, and watch carefully for the first signs of the particular side effects.
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- http://www.essix.com/orstore/default.aspx . 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.
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- http://www.essix.com/orstore/default.aspx . 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.
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.
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