Running Time: 40 min
The use of implants and miniscrews to provide the anchorage necessary for optimal clinical outcomes is an accepted and effective modality. The techniques of
Release Date: September 08, 2012Subtitle:
Delighted to be working with the gIDE Institute, and bring you this presentation that I put together. I’m Doctor Frank Celenza from New York City. I’m a periodontist and an orthodontist, and I’ve spent the last 10 or 15 years working very carefully on combined therapies, such as the use of implants in orthodontics for the purposes of anchorage. And there have been some recent developments and updates that I’d like to share with you this morning, and that’s the purpose of this seminar. This discussion always begins with a review of Newton’s third law, which stated that every action has an equal and opposite reaction. And orthodontists have to live by that dictate. And we adjust appliances and design appliances and treatment plan cases with that in mind at all times. We manage equal and opposite reactions by utilizing anchorage, defined as a body’s resistance to displacement. We define anchorage and treatment plans according to how we intend to use spaces, and we design appliances accordingly. Traditionally, we classified anchorage according to three different classifications. If we say we want to utilize an extraction space by allowing posterior teeth to come forward, that’s known as a minimal anchorage case entailing posterior protraction. If we decide we’d like to split the space between anterior retraction and posterior protraction, that’s called moderate anchorage, or equal space closure. And, as you might anticipate, lastly, a maximum anchorage situation is when we say we want to use all of that space– 2/3 or more of it– for anterior retraction. So traditionally, those three classes of minimal, moderate, and maximum anchorage was how we designed appliances and treatment plans. But with the advent of the use of implants and extra-dental sources of anchorage, we now have at our disposal a new classification of anchorage in addition to those three. And we’re calling this the ultimate class of anchorage, or absolute anchorage. The implication of absolute anchorage is that the appliance becomes entirely under the control of the operator, and the outcome is entirely predictable. Lastly, we can also eliminate patient compliance. So the predictability of the result rises dramatically when we can harness extra-dental sources of anchorage. We do this using implants when necessary. When we have semiedentulous situations which are going to receive implants, we can place implants preparatory towards orthodontics. Or, more recently, we’ve gone to the use of mini-screws, or fixation screws, which have certain advantages as well. Let’s look at a few implant driven anchor situations. Some studies that I did when teaching at New York University bear this out. Use of titanium implants that are integrated as orthodontic anchorage. If we imagine this quadrant as pictured here, the molar with the tube on it is an implant-supported restoration. And I’m showing here a coil spring for the purpose of pushing the cuspid forward into the space that you see existing. And then subsequent to that, the same implant-supported molar used to retract the premolar. So in these two situations, we were testing implants to see how well they responded to both pressure and tension in an orthodontic sense. And at the radiographic level, we were able to see that whereas the teeth show signs of movement– widened ligament spaces, disappearance and reappearance of lamina dura, tooth mobility and tooth relocation, the teeth show those signs– but implants, once integrated, invariably did not. So they served as perfect anchors, not just in our studies, but this is common in the dental literature now. Gene Roberts out of University of Indiana gets credit, certainly, for being one of the pioneers in using implants as orthodontic anchorage. It’s become a very predictable and useful modality, as you’ll see. Furthermore, we’ve seen in the literature that not only are implants excellent sources of anchorage, not only do they withstand orthodontic force, but they also seem to adapt to orthodontic force, and in fact strengthen. And there’s something about the stress patterns set up that are very favorable to implants. So in a direct anchorage sense– meaning that the force for the orthodontic movement is placed directly on the implant– we can see lots of situations where this becomes useful. Let’s compare and contrast what the situation is in the natural dentition, and how we’ve traditionally preserved anchorage. Here’s a patient with a chief complaint of a midline deviation, which we analyzed by way of a diagnostic setup to determine that the upper-left cuspid was oversized because it’s a restoration, and that’s skewing her maxillary arch to her facial right. And so we decided to treatment plan this case and replace that restoration with a properly-sized cuspid, leaving space to its mesial that we would utilize to walk the patient’s midline left. Now, in the natural dentition, which this is, we manage anchorage by outnumbering the active teeth. And you see here the entire left quadrant from the cuspid distal is splinted together effectively by virtue of using the orthodontic appliance for the purpose of joining all those roots to move just the lateral incisor. So you have five or six roots of teeth as the anchor segment, versus the one lateral incisor, which moves very effectively. Then you join the lateral incisor to that splint, adding to its number of roots, for the purpose of moving just the central incisor. And then you can open the midline and go to the other side and move that tooth. So you go through a temporal sequence in the natural dentition to preserve anchorage and get the midline correction that you seek. If at any point you overtax the anchor segment, which is equally as apt to move as the active segment, then that segment would slip mesially, and in the end you don’t get the intended result. So in the natural dentition, we go through a sequence of events to preserve anchorage and prevent it from being lost. And that’s why orthodontics is frequently very time-consuming. Let’s contrast what might happen in an implant-driven anchor system. Now here we have an elderly patient, semiedentulous in the lower left, with what has to be considered a very difficult situation orthodontically, whereby the cuspid has slipped its mesial contact and elevated into the buccal vestibule. So recapturing these teeth and retracting them is very difficult, especially when you consider that she has no posterior teeth to serve as anchor units. Now you might argue, in a case like this, different treatment plans, but I would suggest that one commonly suggested one might be the removal of the first bicuspid to make space for the cuspid, and then a maxillary fixed appliance to allow the use of a class-three elastic to generate the force. So the patient gets braces in the other arch, full treatment, and an extraction, which she can ill afford by conventional orthodontics. And that’s why, since that’s not really a very viable option, that’s why she remains in this condition. But if we change our sequencing and our thought process and consider that, since she is semi-edentulous, she’s going to benefit from implant replacement of teeth. Change the treatment sequence and place the implant preparatory to the orthodontics. And here you can see the implant placed a little distal to where you might think. And now it’s being harnessed as the source of anchorage. And notice the mechanics, how drastically changed they are. First of all, there’s no need for an extraction. Secondly, there’s no need for a maxillary appliance. The implant is used as a direct source of anchorage. And it is also used to retract all three of those teeth simultaneously. There’s no need to go through the temporal sequence that I just outlined in the natural dentition, because there’s no need to preserve the anchorage. The implant is not going to move. And so I can retract all three of those teeth at once, as you see here by the elastics, and in short order, those teeth come back very effectively. Now, we need to be clear. And I’d like to clarify the way I’m saying this. And I will never say that when you utilize implants as anchorage, you can put more force on the teeth, because that’s not the case. The biology of tooth movement remains unchanged, and we know what the most effective force levels are to move teeth efficiently. And we know that excessive force only slows it down. So these teeth are receiving the same light orthodontic force that they always did. The difference is that the implant anchor can take a tremendous amount of force once integrated. And so it provides that we don’t have to do the teeth in sequence. We can do them en masse, or all simultaneously. So there’s a tremendous time savings with this efficiency. And here we can see the case under the control with good arch form retraction. And the implant remains stable. In fact, with more careful planning, we realize that perhaps a second implant could have been placed, which is done subsequently. I used this quotation from the literature which shows how these cases can be planned for the proper implant placement to a post-orthodontic position. Another case showing direct anchorage of an adult patient in a class three, or an anterior crossbite situation, which, in many situations, is an orthodontic surgical diagnosis. Very difficult to jump this crossbite when you have to retract every tooth in the arch to do so by conventional means. But the patient’s missing a tooth in the posterior on each side. We’re going to replace the lower-left bridge anyway. So again, a different thought as to the sequence. Let’s get implants in early. Allow them to integrate. You see these implants placed a little bit distal to the socket because they’re going to be utilized to retract 10 teeth plus a molar. And once integrated and provisionalized, here’s the appliance in place after 11 months of activation. And another beauty of this is, not only did we retract every tooth in the mandibular dentition, but we did it en masse, all at once. There’s no intricate wire bending or need to preserve anchorage. It’s just simple mechanics, with elastomeric and nickel titanium force systems constantly applied. Very light and gradual force. 11 months to jump an anterior crossbite, retracting all 10 teeth plus the molar at once. So the implants are proving to be extremely powerful as anchor systems. And yet they seem to withstand it very effectively. Let’s compare how implant responds to orthodontic force as opposed to occlusal force. Well, in terms of magnitude, in occlusal loading, there are forces in the order of kilograms, which is pretty high. But orthodontic loading is of the order of ounces, even in a heavy situation. Four to five ounces is a lot of force, so the comparison is fractional at best. In terms of duration, occlusal loading is a very sudden occurrence, and it’s over instantaneously. Orthodontic force decays very gradually over a long period of time. So it’s more gentle in that regard as well. And lastly, in terms of direction, an orthodontic force is either pushing or pulling, but it’s clearly uni-directional. Whereas occlusal forces are applied in every direction– mesiodistally, buccolingually, apicocoronally– so it’s far more traumatic to an implant as well. So in all three aspects, orthodontic loading of an implant is, by comparison, very gentle. And for that reason, I can say, in my experience, I’ve never de-integrated an implant with orthodontic force. So we’ve seen some of the implant-driven direct actors, and lately, the mini-screw technique, or TAD, for Temporary Anchor Devices, has become very popular in orthodontics in situations such as this. Now, every orthodontic supply company has TADs, and there are many different variations. They all have certain features that are advantageous. But really, they’re just modifications of fixation screws which we’ve been using for a long time, and they have different heads or attachments on them for orthodontic convenience. One of the early cases here is an indication that we intended to retract her mandibular anterior teeth. She has severely atrophic ridges. And although she is, of course, semiedentulous, not ready for implant placement at this stage. So we went to these cortical mini-screws. Very easy placement through the gingival tissues. Tighten them down bilaterally, and load immediately, retracted all 16 teeth at the time of placement. Movement is very efficient, very effective. We were able to achieve significant retraction, which we analyze cephalometrically. Pre-treatment, we see that we started with a situation where the lower incisor to mandibular plane angle was quite obtuse, whereas post treatment, we retracted it to less than 90 degrees. So we’re able to achieve a lot of dental retraction using these mini-screws. But more importantly, or perhaps more interestingly, we also observed that because these mini-screws were placed quite low in the mandible, below the center of rotation of those anterior teeth, when retracted, we achieved as well as a byproduct, a significant amount of dental intrusion– which, traditionally, by orthodontic means in an adult patient like this, is a very difficult movement to achieve. So we’re starting to see that not only are these systems very effective and very efficient, but they open, perhaps, new treatment possibilities. Intrusion could be a very useful modality in a case like this, where a patient has lost a molar in the lower right for a long time. And over the years, the maxillary molar extrudes into that edentulous space, making restoration very difficult in that region. Here we see the radiographic depiction of that extrusion. You see how the alveolar crest has remodeled in response to that extrusion, and a maxillary molar has tremendous root surface area. It is a very difficult truth to intrude by conventional means. But when we go to extradental sources of anchorage, such as mini-screws, here placed buccal and lingually, for the purpose of running an elastic or a coil spring over the occlusal surface, we’re able to apply the force without having any of the untoward side effects on the neighboring teeth. The anchor system is entirely extradental. And although it’s not an expedient movement, it’s not quick, over the course of a year or so, we are able to achieve a significant intrusion on a maxillary molar, permitting very straightforward replacement of its antagonist. And other situations arises where intrusion can be utilized as well. Here a patient with over-extrusion of the anterior teeth, to the point where the mandibular incisors are incurring palatal impingement, preventing the restoration of these teeth. The beauty of mini-screws is that they are very flexible in location. And we can place them wherever we need for orthodontic convenience, here shown to be placing direct intrusive force onto the anterior teeth in this appliance. And over the period of a few months, we see significant intrusion, that we now begin to see the appearance of the mandibular teeth, where before they were completely hidden. And it gives the restorative dentist sufficient overbite that he now has room for his restorative endeavors and can restore the upper teeth. And many situations arise where we now have other treatment possibilities as well, such as in molar uprighting. Frequently the treatment planning dilemma there is whether to drive the space and open for restoration, or protract the molars into an edentulous to space and close it. Here we see a situation where a molar has collapsed halfway into the edentulous space. And we decide to upright that molar, again, exhibiting flexibility in location. Place the mini-screw into the tuberosity, which is not known to be bone of great quality, but it facilitates the appliance. You see the widened ligament of that molar, showing that it’s being mobilized. And the tooth distalizes, actually, to conflict with the mini-screw at that point, but gives us the space for the placement of a very straightforward implant and subsequent restoration. Situations will rise where it’s also preferable, perhaps, to protract molars and close the space. Now, by conventional orthodontic means, a movement like that is somewhat difficult, although feasible. But it’s facilitated and made much easier through the use of direct anchorage– in this case, a mini-screw. Here, a patient who thought she was being set up to receive implants, only to discover that she had a very atrophic edentulous area, preventing that possibility. Change in treatment plan, and we decided to protract the molars, place mini-screws inter-radicularly. And you see coil springs being directed onto those mini-screws for direct anchorage, so that there is no dental retraction as a byproduct. There is no force on the anterior teeth. The segmental orthodontic appliance is utilized to guide the teeth, and the force comes from the mini-screw. And in the span of under a year, we can achieve some very effective and efficient protractive movements, closing the space. So again, opening up new possibilities that are easily obtained. Now, each of the mini-screws that are designed have certain features which are desirable. There are three segments of the pin that I like to use, in the core, the transmucosal collar, and the head. It has great convenience in terms of applying orthodontic mechanotherapy. And we get comfortable using different ones, and these continue to evolve. But there have been developments in this technology which have led to widespread use and popularity. They’re comfortable. They’re easy to place. They’re removed when they’re no longer needed. And they can be loaded immediately. Just as we learned in some of the earlier days with implant packaging, we can simplify the use of mini-screws with a more effective packaging as you see here, just like we learned with the implant technology. A contour-angle handheld driver eliminates the need for hand pieces, motors. And we can pick up the mini-screw directly from the package and deliver to the mouth without contamination. It became very easy to utilize in a dental setting. So I’ve shown you cases using implants and mini-screws screws in a direct anchor sense, meaning the force is placed directly on that device. There are also techniques known as indirect anchorage, which I’ll briefly outline here. It means that you utilize the device to stabilize teeth, which you in turn apply the force to. And here, when the head of the mini-screw school allows the placement of an orthodontic arch wire like this, we can achieve that technique. So here in a case where we’re looking to distal drive posterior teeth on both sides, I did a direct anchor setup on the right side and utilized these photographs just to show you the differences. There’s a mini-screw between the molars, and the nickel titanium coil spring runs directly to that screw to apply force to the power arm that is on the sectional arch wire. The force goes directly to the mini-screw. In an indirect sense, for the same sort of treatment plan, here the mini-screw is utilized to stabilize the arch wire, against which we push a coil spring. So the force is not directly on the mini-screw, but it is facilitating the stability of the anchor system. And I can tell you from experience, and from this case in particular, when feasible, I think it’s simpler and a lot easier to do a direct anchor setup. It’s just less mechanics, less componentry involved. But there are times when we need to go indirectly. Here’s a case to depict that. An adult dentition, severely constricted and crowded. Potentially an extraction case, which I prefer to avoid whenever possible. After expanding it out, I came to realize that the difficulty would probably be in that upper-left second bicuspid, which is crowded palatally and has great space deficiency there. So there’s a need to drive the molars in the maxilla distally, which is a difficult movement to achieve by conventional means. So here’s the contra-angle that I utilized, placing the mini-screw quite simply here between the cuspid and first premolar in the patient’s upper left, and then utilizing an indirect stabilization system to run a coil spring and drive those molars distally. Previously a difficult movement, but it enables me to attain the space I need to incorporate those premolars as into her arch. And then the mini-screw companies have also come up with some prefabricated devices to be placed palatally, as I did for many years with implants. Now we can stabilize anterior segments using palatally devised orthodontic mini-screws with a prefabricated T bar that we form, eliminating the need for lab processing. So to a large extent, mini-screws have taken over as fantastic sources of anchorage, very convenient and simple to use. And we’ve gone to that extent in many situations. At that time, there are other developments in orthodontic appliance designs and the technique of clear aligner therapy, or Invisalign by trade name, has become very popular and very effective. In the early days, when we doing Invisalign, we were pretty much relegated to simple case types until we got comfortable with the system, until it developed into a more sophisticated platform, which it now is. And I show this case because it really shows the types of situations that we treated in the early days of Invisalign. Here a patient in the maxillary arch with some minor spacing, and the same patient in the mandibular arch with some mild to moderate crowding. These were the case types that we would use Invisalign for to align– minimal to moderate cases. But as we became comfortable with it and started to realize that it, in fact, is a very superior form of removable appliance than what we were traditionally accustomed to, we got a little more daring, and started to realize that other case types became very applicable. In this case, a transverse expansion case very effectively managed with Invisalign. And I came to learn that Invisalign is very effective at expansion-type cases in adults. And then we, of course, started to develop other techniques to supplement our ability to utilize this technique– utilizing auxiliary areas to detail tooth movements, now using fixed, if you will, auxiliary areas in conjunction with aligner therapy to extrude teeth and finish cases more effectively. And Invisalign then responded to that by giving us clear buttons, clear elastics, trying to keep the cases as invisible as possible. And it exhibited their willingness to evolve as we did. And then we started to supplement some of the other movements, rotations, vertical movements, as I showed, which weren’t as effective as we liked. But we’re able to achieve them through other developments like that. And modifying the aligners to allow us to use these auxiliaries, which then became somewhat laborious, because we had to modify each aligner as we do the therapy. So if you have a series of 15 or 20 aligners, each one of them had to be trimmed or modified to allow the use of these auxiliaries. Well, a big breakthrough then came when Invisalign then responded to that by providing us with these precision cuts in the manufacture. And they then said, we can manufacture the aligners with elastic hooks for you to apply the elastic. And we’ll have that in every one of the aligners so you don’t have to modify them. Or we can give you the cutout in the liner to allow you to place your buttons and fixed auxiliaries so that you don’t go through the process of modifying the whole set. And that opened a tremendous pathway for the use of auxiliaries. Now we can apply buttons to the teeth and not have to modify them, and it’s built into them. And we can hold elastics onto the prefabricated hooks. And so now Invisalign becomes a very viable means by which we can introduce intermaxillary elastics– class two elastics to allow class two corrections, full-arch treatments. And in this case, class three elastics. So it’s a very effective and efficient anchor system when you can cook the elastic on and model and apply force to the entire all liner system opened up an entire new pathway to treat much more involved cases. So these game changers in orthodontics have opened up new pathways towards very effective treatments. In a recent editorial in the Journal of Clinical Orthodontics, the editor commented that some fantastic developments in the last few years have really opened up these new pathways. And these game changers he identified as Invisalign, or aligner therapy, and TADs, temporary anchor devices. And these were clearly the game changers in orthodontics in the past few years, opening up new realms of treatment. So as a dual specialist, it becomes natural for me– Invisalign and TADs, let’s combine those therapies and see what we can achieve with those kinds of things. And so here’s a case where I’m showing that I’m using TADs in the maxillary arch for my source of anchorage. And by virtue of the precision cuts in the aligners, I can hook elastics. And this is how I achieve retraction now in a removable appliance that’s invisible and very effective at controlling the entire arch during those movements. And something that I never thought I would do in the early days of Invisalign was now to utilize these very sophisticated and efficient removable appliances for extraction cases and big space closures. As you see here, a patient with extreme excess overjet, maxillary incisor proclination, exacerbated by the lack of two mandibular incisors, giving her an even bigger overjet. It’s important for the Invisalign orthodontist to specify in his prescriptions with his Invisalign technician exactly what his treatments are, so that the orthodontist remains in control of these appliances, and doesn’t pass the treatment planning along to that technician. And so I’m very specific with my instructions in the prescription of these cases. And this is what they call the ClinCheck video, which we use in the treatment planning for Invisalign. And I tell the technician to make the aligners conform to this space closure that we’re showing here. I’ll provide the force. You provide the guidance. And so we can predict in detail these using these treatment planning videos. And that’s how Invisalign works. In this case here, from the side– we launch that video– you see the space closure coming down, the extraction two providing space, and very effective space closure– without any anchor loss, because the force is not coming from the posterior teeth. It’s coming from the buccally-placed mini-screw. So it’s a whole new level of sophistication that we go into. So here you can see now the setup clinically. The upper first premolar has been extracted. The mini-screw has placed into the cortical bone between the second premolar and molar. And I bond a button as far gingivally as close to the center of rotation of the upper cuspid as I can. The patient does not change this elastic, because it doesn’t conflict with the aligner. And I’ll change it every six or seven weeks while the patient changes the aligner every two weeks. So the thought process, and the instruction to the patient, is that the screw and the elastic provide the force. The aligner provides the guidance. And here you can see the teeth retracting. And what I like to see is a small amount of space as the tooth slightly precedes the aligner’s prescription, meaning that the aligner is not really putting the force on the tooth. It’s just guiding it. And the force is coming from the elastic, as I said. And here a little further along. When you allow a little bit of space opening medially to the cuspid, we conform the plastic of the aligner to that surface of the tooth, facilitating the control and guidance of that tooth. And here she is a little closer along, a little further along near the end of space closure. So a tremendous movement with great efficiency in a very comfortable and hygienic and favorable appearance to a great appliance. Here we see tremendous change in the incisor angulation of the maxillary central incisor. The anterior teeth were very proclined pre-treatment, more into a normal triangulation and over jet post-treatment. And so, of course, other case types will arise, and other modifications of this technology. A patient here, an adult male with some degree of maxillary crowding. A very nice class one occlusion on the right side. Left side definitely in a class two situation– accelerated mesial drift locking that lateral incisor out to the buccal. So by conventional means, that might be a bicuspid extraction situation on the upper left. But I prefer to do these non-extraction if I can find a way to drive the upper left dentition distally. And so again, using aligner therapy– which patients are more and more demanding clear aligner appliances– very specific in my prescription to the technician to maintain the right side occlusion, but in the left side, drive those molars up to four millimeters, and give me an appliance that has the provision for the mechanics that I’ll employ. I’ll place a TAD– temporary anchor device– in that quadrant, and I’ll put the force on. Just give me aligners that guide the movement intended. And here you can see the video that will depict that movement. Upper left teeth driving distally, giving the space to incorporate that lateral incisor and achieve a nice maxillary alignment. So if this is the intended treatment plan, the aligners are manufactured from these depictions. And I tell the patient, if that’s what it’s going to look like, that’s what the aligners will be manufactured as. And they will fit. And here we see the side view video of that case. You’ll see the maxillary teeth driving from this class one into a class two. The appearance of those attachments on the teeth are very important to the treatment as well. That helps with the guidance. And through an understanding of the science of these attachments, they facilitate the aligner design and tooth movement. And so it’s important when designing these cases not necessarily to accept the attachment design and location that the technician suggests, but to understand them yourself as an orthodontist, exactly what’s necessary. There’s a science to the location, orientation, and shape of these attachments that it’s important to understand exactly how they should be to maximize the efficiency of the appliance. And so now I like to place these TADs in the palatal location for the purpose of driving. And there are certain features that are very elegant to a design like this. And again, the mini-screw and the coil spring provide the force. The aligners provide the guidance. The beauty of this is, when you can apply the force at some distance away from the crown of the tooth– you can apply the force somewhere up the root surface near the center of rotation of the tooth, as these power arms that I’ve bonded to the palatal surface depict– you can achieve a bodily movement and get great control. So here you have a power arm system hooked to a nickel titanium coil spring, anchored to a mini-screw in the palatal tissue. It fits very comfortably and flush to the patient. It’s very streamlined. And it’s applying force even apical to the center of rotation. So tipping of teeth is not necessarily a limitation of removable appliances any longer. Now we’re applying forces to a much more efficient location than fixed appliances were able to achieve. And here’s the patient as he would appear with that mechanics in place, and post treatment after about 10 months of aligner combined with mini-screw alignment. Here’s pre-treatment, and a nearly perfect class one occlusion. The molar has clearly driven distally. And intercuspation is very acceptable, certainly allowing space to align the anterior teeth. And here you see the maxillary arch form at the completion of treatment. It’s a very simple matter to remove the temporary anchor device. So this is the direction that we’re going now for driving teeth. And here’s a patient, very similar situation, treated with Invisalign through expansion to align the arches and get the teeth into better alignment. In the transverse sense, a very nice result, good midline control. But in the upper right, still the need to drive that dentition distally a little more to achieve a better intercuspation. So a very similar setup to what I just showed you now on the other side. Distal driving the upper right for a saggital correction. Placing a TAD to facilitate the force application. Getting the precision cut prefabricated in the aligner, as I show here. The TAD is placed palatally, where there’s a lot of room between the palatal roots of molars. A power arm placed on the bicuspid to allow force application close to the center of rotation of the tooth. And here you see the placement of the nickel titanium spring. A limitation in this case, certainly, which affected the outcome, was the patient’s unwillingness to extract the maxillary third molar. I still had confidence in the system because of its efficiency, but that wound up limiting the result in the end. There you see the setup and the movement, achieving a nicer intercuspation and jumping a crossbite with the transverse direction as well, getting the midlines into much better coordination. So clearly a direction that we can be taking. And as we do that, and as we develop these techniques, and as I’ve shown you the company’s willingness to modify and adjust with us, now they’re prefabricating these power arms for us so that we can apply the force at different levels and have a prefabricated, bondable power arm, which I now utilize routinely in these situations. So it’s a great partnership between the companies to develop these appliances as we develop the treatment modalities. And then, just an assortment of other case types. Here, a patient semiedentulous with a lot of spacing. We want to treatment plan this case through use of a diagnostic setup to protract posterior teeth. I’m using bilateral mini-screws for that purpose to power arms bonded to the maxillary molars, so that these molars will protract with the force application on the palatal surfaces to prevent their rotation as they mesialize and rotate about the palatal roots. Now we’re combating that and actually forcing the palatal roots forward instead. We’re getting a good setup pre-prosthetically on this case through the combined use of mini-screws and aligners. And so the application to Invisalign, or aligner therapy, expands as well. In many cases, open bites its can be very effectively closed with aligner therapy, because there’s so much contact between the aligner and the dentition that we can determine, sometimes, through the use of mini-screws as the force application. I run mini-screws bilaterally for the application of elastics over the occlusal surface of the aligner, applying a lot of force to those teeth. Certain patient type necessary here, that they’re adept at changing these elastics and have the dexterity to do that every time they replace the aligners. But we’re very optimistic that we can close some significant open bites with mechanics such as this. We’ll see what that develops into. Lastly, a pre-prosthetic case. The patient missing lateral incisors in the maxillary arch bilaterally, with a cuspid in crossbite that has mesialized the whole upper right segment. I would never imagine to do a case like this with a removable-type appliance. But these computer-generated clear aligners are a very superior form of removable appliance. And the treatment plan would look something like this. The removal of the upper right first bicuspid. The placement of mini-screws posteriorly to drive that cuspid in the upper right distally, opening space for implants bilaterally with a midline correction. Great control through the use of carefully-formed aligners. And again, I’m telling the technician that I’ll use a mini-screw and a spring to apply the force. Please give me the aligners that conform to these movements. And very carefully design them in conjunction with the technician. Launching this video to show the cuspid retracting into the extraction space with some midline control, and then opening spaces bilaterally, hopefully for maxillary implants. And we sequence and dictate the movement very carefully, so that the aligners conform to the sequence and movements we desire. And in this case, I elected to retract that cuspid in a crossbite situation, jumping the crossbite only at the end of the retraction. Because in that way, it allows me to have access to the palatal surface of that tooth for bonding the power arm that I described to you previously. OK. So a very effective and efficient treatment to set this case up. In the same visit, I extracted the premolar, placed the palatal mini-screw, bonded the power arm and applied the force, fit the aligners to the patient, instructed him how to wear them, and this case is up and running. Notice the length of the power arm, radiographically and clinically, to allow the application of the force at, or even apical, to the center of rotation of that cuspid, so that in the end we get a bodily movement and parallel routes allowing implant placement. Here you see the retraction ensuing. Cuspid retracting very nicely. And as the mesial surface of that cuspid becomes exposed, I have the aligners designed to conform to that cuspid and apply the force at the CEJ, and control the bodily movement as we retract the tooth as you see here. Very wide ligament space on the mesial surface of that tooth, shown radiographically. And so the conformity of these aligners to the tooth is very important to the guidance of the tooth. There are forces applied to certain aspects of the teeth, and we control bodily movements and tipping movements by very accurate manufacturing of these aligners. So if the fit of the aligner is important to the outcome, the accuracy of the impressioning becomes important. And the development of digital impressioning is now an integral part, in my mind, of effective aligner therapy. For that reason, we’ve gone to digital impressioning using these iTero scan machines, which have great efficiency and provide much more accurate impressioning. And I think that’s very important to the ongoing development of this treatment modality. It’s also much more efficient in terms of sharing the files and moving the files instead of shipping impressions by a courier. These now go digitally over cyberspace. Furthermore, patients are very appreciative and accepting of digital scanning as opposed to conventional impressioning technique. So as all of these developments continue, the technology and efficiency of orthodontics advances tremendously. And so that’s why I say there have been some big game changers in the development of orthodontics recently that I’m very excited about. And so in closing, I’d like to thank you for your interest in this subject matter. I hope you share my enthusiasm for the development of these technologies. And I hope to continue to develop it and push this envelope further.