Orthodontic Perspectives Clinical Information for the Orthodontic Professional Volume XVII No. 1 0.018 Customized and Efficient Treatment Solutions Contents Message from the President 2 Introduction to Incognito Appliance System Mechanics for Non-Extraction and Extraction Cases by Dr. Cliff Alexander 3 Forsus Class II Correctors as an Effective and Efficient Form of Anchorage in Extraction Cases by Dr. Lisa Alvetro 6 Applicability of the Forsus Fatigue Resistant Device as a Class II Corrector in Young Adults by Dr. Chetan V. Jayade 13 A Perspective on Forces, Tooth Movement and the SmartClip Self-Ligating Appliance System by Dr. Garland Watson 18 Dr. Cliff Alexander Dr. Lisa Alvetro Dr. Chetan V. Jayade Introduction to Incognito Appliance System Mechanics for Non-Extraction and Extraction Cases Forsus Class II Correctors as an Effective and Efficient Form of Anchorage in Extraction Cases Applicability of the Forsus Fatigue Resistant Device as a Class II Corrector in Young Adults A Perspective on Forces, Tooth Movement and the SmartClip Self-Ligating Appliance System Dr. Garland Watson
Orthodontic Perspectives is published periodically by 3M Unitek to provide information to orthodontic practitioners about 3M Unitek products. 3M Unitek welcomes article submissions or article ideas. Article submissions should be sent to Editor, Orthodontic Perspectives, 3M Unitek, 2724 South Peck Road, Monrovia, CA 91016-5097 or call. In the United States and Puerto Rico, call (800) 852-1990 ext. 4399. In Canada call (800) 443-1661 and ask for extension 4399. Or, call (626) 574-4399. Copyright 2010 3M. All rights reserved. No part of this publication may be reproduced without the consent of 3M Unitek. 3M, Clarity, Forsus, Incognito, MBT, and SmartClip are trademarks of 3M. Other trademarks are property of their respective holders. Visit our website at www.3munitek.com Message from the President Paul Keel Spring is upon us once again. The cherry blossoms are blooming in Washington D.C., the green shoots of economic recovery are poking through, and patient traffic in many offices is growing. What a welcome difference a year makes. With this as a backdrop, I wanted to share 3M Unitek s top priorities for 2010: 1 Customers 2. Employees 3. Innovation On the Customer front, our guiding vision is to be the most trusted provider of innovative and personalized solutions to orthodontic professionals and their patients. We ve built this trust over the sixty plus years that we ve been in business. We understand that our success is directly tied to your success. When you grow, we grow. So we invest heavily in your future as well as our own. We re a leading supporter of the AAOF, a primary donor to residency programs around the globe, and the exclusive sponsor of Smiles Change Lives, an organization that delivers orthodontic care to low-income families. We also support your development through our education efforts, such as Orthodontic Perspectives. This year alone, we ll conduct over a hundred courses and host thousands of doctors and staff. We sponsor every US and Canadian Resident to attend a Bottom Line Program Summit at some point in their training. And in today s world of electronic communication, we recently launched www.3munitektraining.com, a state-of-the-art, on-line learning center. This educational site offers no-cost, accredited, educational materials covering a broad array of products and techniques. On the Employee front, we are proud to have the best team in the industry. Leveraging 3M s unmatched global reach, we have customer care representatives on the ground in over sixty countries. We conduct frequent in-person and electronic training events to assure that these representatives bring you the most relevant and timely information available. This year we ll continue to add to our global team, and appreciate the warm welcome you extend to our new team members. On the Innovation front, we consistently lead the industry in research, development and new product introductions. 3M was named the #1 Innovator in the Dental Industry by the Anaheim Group for the 5th consecutive year. Our philosophy is not to try and change the way you treat. Rather, we offer the best solutions to support your preferred approach with trusted brands that you know well. Victory Series has long set the pace in conventional metal appliances just as SmartClip is now doing in SL. Transbond, APC, Clarity and Forsus brand products have broadened their market leadership with continuous advances and extensions. And the Incognito Appliance System is fast becoming the gold standard for orthodontists who choose to treat invisibly. Thank you for your help and support. We hope both the Spring and this issue bring you growth. Best, Paul
Introduction to Incognito Appliance System Mechanics for Non-Extraction and Extraction Cases by Cliff Alexander DDS, MS Dr. Cliff Alexander practices orthodontics with his father, Dr. C. Moody Alexander, in the greater Dallas area. Alexander & Alexander Orthodontics specializes in offering its patients leading-edge orthodontic services such as the Incognito Appliance System. He is also a Board Member of the Alexander Foundation for Orthodontic Research and Education (AFORE), a nonprofit organization dedicated to studying, enhancing, and disseminating the Alexander Discipline philosophy and technique to doctors worldwide through research, education and collaborative efforts. A noted teacher and lecturer, Dr. Alexander regularly addresses academic and dental groups on a variety of orthodontic subjects. He is a featured speaker at the annual 3M Unitek Summit, where he teaches an Incognito Appliance System Certification Course for orthodontists and staff. This popular program provides an overview of the Incognito System technique and gives an in-depth look at key clinical procedures, case selection and successfully presenting the system to patients. Dr. Alexander also presents the program at the American Lingual Orthodontics Association (ALOA) Congress. Dr. Alexander graduated from Baylor College of Dentistry in 1993 and the St. Louis University Department of Orthodontics in 1996. He is a part-time faculty member at St. Louis University, where he lectures on the Alexander Discipline and the Incognito System and oversees orthodontic patient care once a month. He is a member of the Incognito Appliance System clinical advisory board, and has treated more than 200 Incognito System patients in his practice. Most current lingual appliances are designed to treat a limited range of cases, to treat the Social Six in an aesthetic fashion. Many clinicians may use removable aligners to treat these cases. While my practice offers removable aligners to a limited degree, many patients who prefer an aesthetic solution have more complex cases. In order to provide the best service to my patients I needed an aesthetic appliance that could treat any type of case from limited 3-3, to severe and complicated malocclusions all to a high degree of quality, just like my labial appliance. After I transitioned from the traditional lingual appliance to the Incognito Appliance System and had finished a few cases, I began to realize that it was giving me the same treatment outcome as my labial appliance. I have 15 treatment objectives that I try and achieve with all comprehensive cases called the 15 Keys to Success (Figure 1). It became very clear to me that I now had another appliance in my arsenal that could satisfy those same goals for any malocclusion, any patient and do it invisibly. 15 Keys to Success 1 IMPA = < 3 degrees Root Positioning: 2 SN-MP = (+/-) 3 degrees 11 Anterior roots divergent 3 U1-SN = 101-105 degrees Mandibular first molars upright Extraction sites parallel 4 U1-L1 = 130-134 degrees 5 ANB = 1-3 degrees 12 Periodontal Health 6 Mandibular intercanine width = within 13 Temporal Mandibular Joint 1.5 mm of original width 7 Maxillary intermolar width = between Soft Tissue Profile: 34 and 38 mm 14 Lips touching when relaxed Harmony line touches chin and lips 8 Archform = Ovoid while bisecting the nose 9 Leveled mandibular arch, flat Curve of Spee Occlusion: Good Intercuspation 10 CO = CR Anterior guidance Canine protected discclusion Figure 1: Dr. Alexander s 15 Keys to Success. One of the most common questions among new Incognito System users is If I m going to use lingual, what would I do here, in this case? Always, my response is simply What would you do if it was labial?! It may have been true in the past that there were compromises treating with a lingual appliance because it couldn t do everything that a labial appliance could do, however, that is no longer true. While certain mechanics and ligation techniques may be slightly different, the application is the same and any auxiliary (elastics, TADs, headgear, Class II Correctors, etc) can be used with Incognito System with simple, but proper, planning. To illustrate this point, let s look at the mechanics used to treat non-extraction and extraction cases with the Incognito System. 15 Smile: Symmetric midline Smile line/arc Broad smile, no dark buccal corridors 3
Non-Extraction Mechanics and Tips Non-extraction crowded cases are treated with similar mechanics as with labial appliances. Depending on the treatment plan, the objective is to resolve the crowding with either transverse expansion, sagital protrusion, interproximal reduction or a combination of the three. As with labial appliances, the goal is to start with light round archwires to unravel the arches achieving full slot engagement and allowing the initial wires to become passive before progressing to the intermediate and eventually the final archwire. With lingual appliances there can be reduced interbracket distance in the lower anteriors region due to the smaller size of the teeth, profile of the brackets, and decreased arch length going from labial to lingual. However, with the Incognito Appliance System, this is not an issue as long as there is enough room to bond all of the brackets. There is a self-retaining auxiliary slot (Figure 2) that doubles as the incisal tie-wing of the bracket that allows the clinician to simply snap a light round NiTi archwire into and after a few weeks the crowding is resolved. 0.018 My very first Incognito System case was a Class I, moderate crowded case that had requested removable aligners. While aligners may have been successful, I felt I needed more control and offered the Incognito System to the patient. While my first case took a couple of months longer than it probably would now, she and I both understood that we were learning a new system and that was part of the deal. I learned some lessons on this case that I needed to do differently in terms of ligation that would have achieved better root position for example, but overall the patient and I were both very pleased with the results. Extraction Mechanics and Tips Though different from the closing loop technique that I use on my labial cases, en-masse retraction is an effective way to close space with the Incognito System. With Incognito System, we unravel six anterior teeth and retract en-masse. I encourage taking a three phase approach to extraction treatment with Incognito System. Phase I consists of a light round ideal archwire and slowly unraveling the six anterior teeth, usually NOT engaging all six initially but rather sequentially slowly distalizing the canines, then the laterals until all six can be engaged completely, aligned and space consolidated 3-3 (Figures 4, 5 and 6). 2A Figure 2A: Self-retaining auxiliary slot. 2B Figure 2B: Use of self-retaining slot. Incognito System brackets are also very low profile. The low profile helps to create more interbracket distance and working space, which is helpful when there is crowding. Then the case progresses as a normal non-extraction case with the intermediate and final archwires. 4 Figure 4: Phase I. 5 Figure 5: Phase I continued. The compressed archwire technique can be used to create space particularly when there is not enough room to bond all brackets or engage the archwire in every bracket. The archwires are all formed, from initial to final archwire, in the exact same archform. So that initial archwire is a reflection of the archform being expanded with the teeth aligned. Yet, the clinician is going to place that ideal archform into a very un-ideal arch, one that has less arch length than the wire itself. So if each tooth cannot be engaged, then there has to be some way to maintain the ideal arch length in the anterior. This is accomplished by utilizing a stop, either a crimped stop or using the canine/bicuspid offset if present, to maintain the arch length 3-3 (Figure 3). 6 Figure 6: Phase I continued. Phase II involves space closure. Proceed to the space closure archwire, which is a rectangular archwire that controls the torque of the six anteriors and is straight from the mesial of the first premolars to the distal of the second molars. The reason for this is that sliding mechanics are used instead of closing loops and if there are any bends distal to the first premolars in the customized, robotically bent archwire, then it will bind and not slide through the slots (Figure 7). The typical Phase II archwire is a.016".024" Stainless Steel archwire that has additional labial crown torque Figure 7: Archwire Example. 3A 3B 7 Figure 3: Compressed Archwire Technique with Stop. 4
added 3-3. This wire is undersized to allow sliding mechanics to be unencumbered and the additional torque is strictly to make this undersized wire fully engage the slot for bodily control of the anterior segment during retraction. Adding torque to the archwire ensures that torque control is maintained; that the incisors and canines do not tip lingually. Ligations in this space closure archwire are critical as well. The six anteriors are laced tightly together to maintain space consolidation (Figure 8), the canines are tied with a steel overtie, the posterior are ligated with steel and power chain is used from the second molar to the canines to retract the anterior segment (Figure 9). The power chains are replaced in 4-6 weeks. Probably the most important of these ligations are the steel overties on the canines. These ensure that the wire will stay fully engaged in the canine slots and that the roots will distalize bodily. Closing Comments In summary, the Incognito Appliance System has evolved greatly over the last few years and will continue to do so. It is an orthodontic appliance system that can treat very simple, limited cases as removable aligners and Social Six appliances do or it can treat the most difficult cases possible and with the same appliance auxiliaries and treatment modalities that the orthodontist would normally use with his labial appliance. In the end, both the patient and doctor will be pleased with such high quality results using the highest end orthodontic appliance. Note from Editor: Non-Extraction and Extraction Mechanics will be covered in detail at the forthcoming Incognito Appliance System 5th Annual User Meeting, October 22-23, 2010, in Las Vegas. For more information on this event please go to www.3munitek.com. Once all of the extraction space is closed then Phase III is initiated with a full size, stiff, rectangular archwire for final 1st, 2nd and 3rd order corrections. Elastics are used as necessary during Phase II and Phase III for gaining a complete and functional occlusion. 8 9 Figure 8: Anterior Ligations. Figure 9: Ligation Techniques. 3M Named Top Technical Innovator Worldwide #1 Innovation is not just a goal at 3M. It s reality. The 2009 Dental Industry Review, published by the Anaheim Group, has named 3M Company the #1 technical innovator for 2009. In fact, this is the fifth year in a row that 3M has held the prestigious #1 spot in this comprehensive annual industry report. The Dental Industry Review looks at companies worldwide and creates a technical Innovation Index for its report. Over the last five years, 2005-2009, 3M has been credited by the report with nearly double the total number of innovations of its nearest competitor. The report includes Danaher, Dentsply International, and Align Technology, among others. #1 technical innovator for 2009 5
Forsus Class II Correctors as an Effective and Efficient Form of Anchorage in Extraction Cases by Lisa Alvetro, DDS, MSD After receiving her DDS summa cum laude from Ohio State University, Dr. Alvetro completed her residency at Case Western Reserve University and now lectures there as an Associate Clinical Professor teaching Practice Management. After more than 16 years of private practice in Sidney, Ohio, Dr. Alvetro continues to focus on team development, innovative products and efficient processes to sustain a quality practice. Forsus Class II Correctors: A Reliable Anchor The Forsus Class II Corrector has been shown to be an effective appliance in the correction of Class II malocclusions. Its success lies with its ease of use, durability and independence from patient compliance. Often practitioners consider its use instead of headgear and Class II elastics. However, as we continue to gain clinical experience with the appliance we have found it also to be very useful in treating extraction cases. When a Forsus corrector is incorporated into our treatment protocol for patients that require extractions we find an increase in efficiency and predictability of treatment outcome. In extraction cases a headgear can be useful as maxillary anchorage in maintaining molar position during anterior retraction. Maintaining maxillary molar position and avoiding anchorage loss is often required to achieve an ideal occlusion and optimal facial esthetics. However, the use of headgear is completely dependent on patient compliance, leaving the success of our treatment in the control of our patients. Our alternative is to use the Forsus appliance as a headgear. We use it to maintain maxillary anchorage or distalize the maxillary molars to obtain a Class I molar relationship during the closure of extraction spaces. This approach is independent of patient compliance and ensures a successful treatment outcome. In extraction cases, another clinical challenge can be to maintain mandibular incisor position and torque during mandibular space closure. Often when attempting to slide the mandibular posterior buccal segments forward the mandibular incisors respond by retracting or losing torque resulting in an increase in overjet. We have found the Forsus corrector to be the solution to this clinical situation by using the mesial force of the pushrod to maintain the incisor position. Therefore, the Forsus corrector is serving two roles during extraction space closure. In the maxillary arch it acts as a headgear for anchorage during maxillary retraction and in the mandibular arch it maintains mandibular incisor position during posterior protraction (Figure 1). Our standard Forsus corrector set up for space closure is seen in Figure 2. Our bracket selection is SmartClip SL3 Self-Ligating Appliance System utilizing the MBT Versatile+ Appliance System prescription with -6 of torque in the mandibular incisors. Our standard installation uses a ligature with bite guard on the 1st bicuspid under the mandibular 19 25 beta titanium archwire. The maxillary archwire is a posted 19 25 NiTi for the Forsus Fatigue Resistant Device. The rod size is selected for ideal activation of 200 grams. NiTi coil springs are attached to the maxillary 1st molars and posts on the maxillary archwire. In the mandibular arch the NiTi coil springs are attached to the mandibular 1st molar and onto the cupid brackets with a wire ligature. 6 1 Figure 1: Force vectors associated with Forsus Class II Correctors. 2 Figure 2: Typodont photo to demonstrate space closure set up.
NiTi coil springs are selected to provide the force for space closure due to their ability to provide a constant force on the dentition that does not degrade over time. The strength of the NiTi coil springs is selected based on molar and incisor position. Sliding mechanics in the posterior buccal segments are enhanced due to the reduced friction environment provided by the SmartClip Self-Ligating Bracket. Therefore, the combination of the constant force of the NiTi coil spring and the SmartClip brackets creates an efficient system for space closure. NiTi Coil Spring NiTi Coil Spring 75 grams Forsus Class II Correctors 100 grams NiTi Coil Spring 75 grams If the Forsus Appliance is ideally activated at 200 grams it can be assumed that it exerts a distal force of 100 grams on the maxillary molar and a mesial force delivered by the pushrod of 100 grams in the mandibular arch. If a NiTi coil spring is selected that delivers 200 grams of force, it can also be assumed that the force will be exerted equally in a mesial and distal direction. In the maxillary arch 100 grams of mesial force is exerted on the molars by the NiTi coil spring and 100 grams of distal force is exerted on the anterior teeth through the post on the archwire. The distal force of the Forsus corrector on the maxillary molar counteracts the mesial force exerted by the NiTi coil springs. The result is that the maxillary molars maintain their position while the anterior teeth retract. In the mandibular arch the NiTi coil springs exert a mesial force of 100 grams on the molar and a distal force of 100 grams on the anterior teeth through its attachment on the cuspid. The 100 grams of force exerted by the Forsus corrector pushrod is used to counteract the 100 grams of distal force of the NiTi coil springs that is placed on the mandibular anterior teeth. The result is that the mandibular anterior teeth remain in position and the mandibular posterior segment protracts (Figure 3). 4 Forsus correctors 100 grams NiTi Coil Spring 100 grams Figure 4: Reduce the strength of the maxillary NiTi Coil Spring to prevent mesial molar advancement. In Class II cases, this force imbalance can be used to distalize molars. NiTi Coil Spring NiTi Coil Spring 100 grams Forsus correctors 100 grams NiTi Coil Spring NiTi Coil Spring 100 grams NiTi Coil Spring NiTi Coil Spring 100 grams Forsus Class II Correctors 100 grams 5 NiTi Coil Spring 75 grams NiTi Coil Spring 75 grams NiTi Coil Spring NiTi Coil Spring 100 grams Forsus Class II Correctors 100 grams NiTi Coil Spring 100 grams Figure 5: Reduce the strength of the mandibular NiTi Coil Spring to prevent anterior torque loss and potentially uprighting the mandibular incisors. If at any time during maxillary space closure it appears that anchorage is being lost and the maxillary molars are slipping mesially, the strength of the NiTi coil spring is reduced. This reduces the mesial force placed on the maxillary molar by the NiTi coil spring. In a Class II molar relationship, this imbalance of force where the distal force is greater on the maxillary molar than the mesial force of the NiTi coil springs can be used to distalize the maxillary molars during maxillary anterior retraction to obtain a Class I relationship (Figure 4). Forsus correctors 100 grams 3 NiTi Coil Spring 100 grams NiTi Coil Spring NiTi Coil Spring 100 grams Figure 3: With equal counteracting force at the maxillary molar and the mandibular anterior segment, NiTi Coil Springs retract maxillary anterior teeth and protract the mandibular posterior segment. During mandibular space closure, if the mandibular incisors appear to be losing torque or retracting, the strength of the NiTi coil springs in the mandibular arch is reduced. This reduces the distal force from the NiTi coil spring on the mandibular anterior teeth. This imbalance of force results in a greater mesial force from the Forsus corrector springs, and the mandibular incisors procline (Figure 5). 7
In the clinical situation where both the maxillary molars need to be distalized and the mandibular incisors to be advanced, the force produced by the Forsus Appliance springs can be increased by the addition of a split crimp. This additional activation will increase the distal force placed on the maxillary molars by the spring module and increase the mesial force placed on the mandibular incisors by the pushrod. The forces produced by the NiTi coil springs in the maxillary and mandibular arches will remain the same. The net result is a greater distal force on the maxillary molar producing distalization while still retracting the maxillary anterior teeth. In the mandibular arch, the posterior teeth protract while the mandibular incisors upright. Case 1 The initial photos and cephalometric film of a 13 year old patient are seen in Figures 6-7. Due to the amount of crowding it was determined that extractions were needed. When considering the anterior posterior relationship of the maxilla to mandible, it was determined that to achieve optimal alignment and occlusion a Forsus appliance would be used in combination with our SmartClip Self-Ligating Appliance System. As part of our treatment plan, the maxillary 1st bicuspids and mandibular 2nd bicuspids were extracted. The maxillary and mandibular arches were leveled and aligned without any attempt to close extraction spaces. Instead the extraction spaces were only used to align the dentition and position the incisors within the maxillary and mandibular arches. The cephalometric film taken at 12 months treatment progress is immediately prior to Forsus corrector placement (Figure 8). The mandibular archwire is the 19 25 Beta wire and the maxillary arch is a posted 19 25 Nitinol wire. Note that a Class II molar relationship, overjet and extraction space still exist in the malocclusion. When the Forsus corrector is placed, the NiTi coil springs are attached in the maxillary and mandibular arches as shown in Figure 2. The NiTi coil springs will close the extraction spaces while the Forsus corrector will act as maxillary anchorage and support mandibular incisor position and correct the anterior posterior relationship. Figure 9 demonstrates the extraction space closure, molar relationship and overjet after Forsus corrector and NiTi coil springs have been in place for 3 months. 6A 6B 9A 9B 6C 9C 9D 6D 6E 9E 9F 6F Figure 6: Case 1 maxillary 1st bicuspids and mandibular 2nd bicuspids were extracted. 6G 9G Figure 9: At 15 months into treatment, 3 months wearing Forsus Appliances. 9H 8 7 8 Figure 7: Initial cephalometric x-ray. Figure 8: 12 month cephalometric x-ray, before Forsus Appliance installation.
Case 2 Although the patient in Figure 10 has a Class I molar relationship, evaluation of the initial cephalometric film (Figure 11) reveals a discrepancy between the maxilla and the mandible. Therefore our treatment plan included the use of the SmartClip Self-Ligating Appliance System combined with Forsus Class II Correctors. To alleviate the crowding within the arches an extraction pattern of maxillary and mandibular 1st bicuspids was selected. Figure 12 is the post leveling aligning progress cephalometric film. This film is pre extraction space closure and pre Forsus corrector placement. Since the mandibular 1st bicuspids were extracted a variation of our Forsus corrector placement exists. In this case the Forsus corrector pushrod is located distal to the mandibular cuspids. The NiTi coil springs are attached in the standard location. 10A 10B 10C 10D 10E 10F Figure 10: Case 2. 10G 10H 11 12 Figure 11: Case 2 initial cephalometric x-ray. Maxilla and mandible discrepancy. Figure 12: Case 2 progress cephalometric x-ray after levelling and aligning. 9
Case 2 progress photos are shown (Figure 13) at 15 months total treatment time. The Forsus Class II Corrector and NiTi coil spring combination have been in place 4 months to close the maxillary and mandibular extraction spaces and establish a Class I molar and cuspid relationship. Our clinical protocol is that once the maxillary and mandibular extraction spaces are closed and an ideal overjet and molar relationship achieved, the Forsus correctors and the NiTi coil springs remain in place passively for one 6-8 week appointment interval. At the next appointment the Forsus corrector and NiTi coil springs are removed. To ensure that extraction spaces remain closed the maxillary and mandibular arches are be chained with power chain from first molar to first molar. The case now proceeds into the finishing stage of treatment. Progress photos taken at 19th month of treatment (Figure 14) are 2 months post Forsus corrector removal with the case requiring a slight amount of midline correction following settling of the occlusion. 13A 13B 13C 13D 13E 13F Figure 13: At 15 months into treatment, 4 months wearing Forsus Appliances. 13G 13H 14A 14B 14C 14D 14E 14F Figure 14: At 19 months into treatment, 8 weeks after Forsus Appliance installation. 10 14G 14H
Total treatment time for this patient was 20 months. Treatment results are seen in Figure 15 and Figure 16. Positive changes were observed in the facial profile and aesthetics (Figure 17-18). A comparison of the initial malocclusion and final occlusion demonstrates a pleasing result (Figure 19). 15 Figure 15: Final cephalometric x-ray. 16A 16B 16C 16D 16E 16F Figure 16: Final Case 2 photos. 20 months of treatment time. 16G 16H 17A Figure 17: Case 2 pre- and post-treatment. 17B 11
Figure 18: Case 2 pre- and post-treatment. 18A 18B 18C 18D 18E 18F Figure 19: Case 2 pre- and post-treatment. 19A 19B 19C 19D Conclusion: The combination of Forsus Class II Correctors with the SmartClip Self-Ligating Appliance System can create an efficient treatment protocol in extraction cases. The loss of maxillary anchorage and control of mandibular incisor position is no longer a challenge during space closure. Clinically its ease of use and acceptability by patients makes it an excellent treatment choice for many cases. We appreciate the predictability and independence from patient compliance that ensures successful treatment outcomes. 12 Case photos provided by Dr. Lisa Alvetro.
Applicability of the Forsus Fatigue Resistant Device as a Class II Corrector in Young Adults by Chetan V. Jayade, DDS Dr. Chetan V. Jayade received his BDS at Karnataka University in 1997, his MDS at Rajiv Gandhi University in 2001 and his MOrthRCS at Edinburgh in 2004. He is currently on faculty at Panineeya Dental College in Hyderabad, India. His Masters dissertation won the National Award for Best Thesis in 2001, and since then he has had been published four times in Indian journals and has three publications in international journals. He presented a paper about the Forsus Fatigue Resistant Device at the World Federation of Orthodontists Congress in Paris, 2005. Fixed functional appliances (Class II correctors) are an integral part of an orthodontist s armamentarium, owing to their ability to correct Class II malocclusions without relying on patient compliance. Although their use has traditionally been restricted only to growing individuals, recent studies have documented successful use of compliance-free Class II correctors in young adults as well. Data from various research groups in Europe indicates that appliances such as Herbst and Functional mandibular advancers are also successful in Class II correction in adult Class II patients 1,2,3. Pancherz has rightly termed this as a shifting paradigm in Class II treatment options. MRI data of adult patients undergoing fixed functional treatment have demonstrated the possibility of condylar remodeling in adults too 4. This fact has surely opened new doors of exciting possibilities for Orthodontists. For the past seven years, the Forsus Fatigue Resistant Device has been used in my practice and by our residents in over a hundred Class II patients. In young adults also, we have had predictable results, and in this paper I will also enlist suitable situations in which Forsus corrector can be used effectively in adults. Modifications in usage and their rationale will also be described. Need for Class II Correctors in Young Adults There are, in my opinion, four main indications of Class II correctors in young adults, namely: Skeletal Correction in patients with mild skeletal Class II malocclusion. Borderline Class II cases with deficient mandible (LANB 4-6 degrees) are suitable for this approach. However, obvious surgical cases are a contra-indication to such treatments. It is also important to consider that these individuals should not be seeking drastic changes in their facial appearance. Dental Class II malocclusion correction only. Obviously, the amount of skeletal correction achievable in adults is much less than in adolescents (only 30-40% skeletal changes may be expected). Therefore, the best results in young adults are those cases which have mainly a dental component of Class II without an underlying skeletal discrepancy. Correction of Class II subdivision malocclusion patients having a mandibular midline shift. In these cases, by selective differential force selection on either side, subdivision correction becomes more predictable, while addressing the lower midline. Class II dental malocclusion requiring maxillary molar distalization. Again, in these cases, selective molar distalization, on one side or bilaterally, is easily effected by minor variations during appliance installation. Forsus Fatigue Resistant Device as an Efficient Class II Corrector The Forsus fatigue resistant device satisfies all requisites of an ideal Class II corrector, namely, is very simple to use, comfortable to the patient, corrects Class II malocclusions effectively and the fact that all this is achieved without problems of breakage is an added bonus. 13
14 Among five brands of Class II correctors I have used on patients, the Forsus Class II Corrector has proven to be most comfortable to a patient, right from installation itself. The Forsus corrector, not being as forceful as Herbst, allows gradual overpowering of the patient s oral musculature. On the day of insertion, the patient does not experience any pain. Within a month, at the time of recall, it is generally observed that a part of Class II correction would be initiated. This, by itself, is a big motivational feature for me. Whenever a patient is apprehensive about having a Forsus corrector in the mouth, I introduce him to another who already has it in place. The latter s positive experience helps in encouraging the new patient too. Clinical Protocol There are a few changes that I make before placement of Forsus corrector in a patient. These are essential to get an improved biomechanical vector as well as to minimize unwanted dental effects, especially lower incisor proclination and buccal flaring of upper molars. The fixed appliance prescription of choice is the MBT Versatile+ Appliance System with 0.022" slot brackets. As is expected with fixed Class II correctors, due to applied force vectors, upper incisor torque loss and labial flaring of lower incisors is bound to happen. MBT system brackets, with relatively high lingual root torque in upper incisors and -6 degrees of labial root torque in lower incisors, have better capabilities in resisting both these untoward effects. In the upper arch, necessarily, second molars are banded. This prevents a step from being created between the first and second molars during the Forsus corrector phase. It is important that the wire sizes at the time of inserting the Forsus device should be 19 25 SS. In my use of the appliance, the upper archform is constricted by 2 mm on either side and additionally supported by a Zachrisson type TPA to prevent buccal rolling of the molars. As per the need of the case, additional lingual root torque in the upper archwire and extra labial root torque in lower wire is added to further prevent the above mentioned side effects. The lower wire is always cinched back. Upper wire may or may not be cinched back based on the need for molar distalization. When one needs distalization, 2-3 mm of wire is left projecting from the tube intentionally to allow molars to freely slide under the influence of the Forsus correctors (refer to Case 3). Improved Biomechanical Vector Instead of hooking the push rod directly on a plain archwire next to a bracket, I make an omega loop in the 19 25 SS wire (Figure 1) and then insert the push rod onto this hook. Before placement, the pushrod is also given an inward bend to follow the curvature of the lower arch and vestibule. This displaces the force vector closer to the Cres of the mandibular dentition (Figure 2). In turn, what is expected is more of a bodily movement of the lower dentoalveolar segment than mere steepening of the occlusal plane. Additionally, this modification helps prevent canine bracket breakage and makes it less visible. Also, while doing such a modification, we have observed a phenomenon of alveolar bone bending. This phenomenon was documented by Schwindling 5 in his book and we verified it in an earlier research project 6. On a personal basis, I feel this phenomenon of alveolar bone bending, if seen in many cases and remains stable over an extended time period, may be of prime importance in achieving a good dentoalveolar camouflage in skeletal Class II young adults. What it would essentially mean is that instead of simply proclining lower anteriors (which jeopardizes their periodontal integrity) while using a Class II corrector, the entire alveolus gets bent and aids the overall correction since active bone growth is complete in young adults. 1 2 Figure 1: Omega Loop bent into mandibular archwire for push rod placement. Figure 2: Slight bending of push rod after inward bend is made. Duration of Forsus Class II Corrector Usage Most clinicians prefer to keep Forsus device only for 4-5 months in majority of patients. However, data of Rabie and co-workers has defined the appropriate duration of fixed functional appliances as being close to one year. This was derived by extrapolation from their animal experiments 7. Based on these lines, I prefer leaving the Forsus device for an average time period of 7-8 months. Activation of the appliance is done either at the L-pin end by pulling it mesially, or adding the split crimps provided with the kit. After the appliance is in place for 4-5 months, one might see the overjet reducing rapidly and the patient achieving an edge-to-edge relation. From this point onward, I deactivate the appliance by loosening at the L-pin and leave the Forsus device in place for at least a couple of months. This way, we obviate the need for an additional retention appliance while stabilizing the achieved result. Case Reports In this section, three cases are shown which correspond to the earlier discussion. Treatment of two female patients SP (Case 1; Figures 3-7) and RM (Case 2; Figures 8-10 ) of ages 16 and 17 with Class II div 1 and div 2 malocclusions respectively is depicted to illustrate benefits of the Forsus Fatigue Resistant Device in bilateral Class II correction. In both cases, initial leveling and aligning was done with NiTi wires. The Forsus corrector was placed after placing 19 25 SS wires. Activation
of the push rod was needed only in SP since she had a large overjet of 10 mm to begin with. Very little finishing is required after Forsus Class II Corrector phase, and one can witness excellent overjet reduction and good Class I buccal segment relationship. Cephalometric superimpositions show minimal proclination of lower incisors. Case 1 The third case, SK (Figures 11-13), a 24 year old male reported with a large overjet, overbite and a unilateral half unit Class II relation on the left side. He also had a compromised periodontal status. Unilateral molar distalization was achieved on the left side during the Forsus corrector phase by leaving the end of the upper wire uncinched on the left side. 3A 3B 3C 4 5 Figure 4: Case 1 pre-treatment. Figure 5: Case 1 pre-treatment. 3D 3E 3F 6A 6B Figure 6: Case 1 during treatment. 3G Figure 3: Case 1 pre-treatment. 3H 3I 6C 7A 7B 7C 7D 7E 7F 7G 7H 7I Figure 7: Case 1 post-treatment. 15
Case 2 8A 8B 8C 8D Figure 8: Case 2 pre-treatment. 8E 8F 9A 9B 9C 9D 9E 9F Figure 9: Case 2 post-treatment. 9G 9H Figure 10: Case 2 post-cephalometric superimposition. 16 10
Case 3 11A 11B 11C Figure 11: Case 3 pre-treatment. 11D 11E 12A Figure 12: Case 3 during treatment. 12B 12C 13A Figure 13: Case 3 post-treatment. 13B 13C Conclusion Most Orthodontists are skeptical about using a fixed functional appliance after the end of pubertal growth spurt in their patients. Instead of compromising on facial appearance by extracting only upper first premolars (which leads to unaesthetic appearance in some cases) or resorting to an invasive procedure such as an orthognathic surgery for borderline skeletal malocclusions. The clinician now has the ability to use the Forsus Fatigue Resistant Device to correct Class II malocclusions in young adults in a predictable manner. One has to be careful though, in ensuring limited side effects of the Class II corrector by taking adequate precautions as mentioned earlier. I see this application as a potentially practice-transforming technique and recommend it to practitioners who haven t used Forsus correctors in young adults. So, what are you waiting for? Go ahead and give the Forsus Fatigue Resistant Device a try. I bet you will enjoy the experience. The satisfaction on the patient s face after treatment will surely be a driving force for your future patients too. References 1. Ruf S, Pancherz H 1999a Dentoskeletal effects and facial profile changes in young adults treated with the Herbst appliance. Angle Orthodontist 69:239-246 2. Ruf S, Pancherz H 2004 Orthognathic surgery and dentofacial orthopedics in adult Class II div 1 treatment: mandibular sagittal split osteotomy versus Herbst appliance. American Journal of Orthodontics and Dentofacial Orthopedics 126:140-152 3. Frye L, Diedrich PR, Kinzinger GS 2009 Class II treatment with fixed functional orthodontic appliances before and after pubertal growth peak a cephalometric study to evaluate differential therapeutic effects. Journal of Orofacial Orthopedics. 70(6): 511-27. 4. Kinzinger GS, Gulden N, Diedrich P 2006 Disc-condyle relationships during Class II treatment with the Functional Mandibular Advancer (FMA). Journal of Orofacial Orthopedics. 67(5): 356-75 5. Schwindling MP 1997 Jasper Jumper Color Atlas: Class II correction without compliance problems. Needham Press. 6. Taneja T, Jayade VP. Skeletal and Dental effects of Forsus FRD - A prospective study Masters Dissertation submitted to the Rajiv Gandhi University of Health Sciences 2005. 7. Rabie AB, Xiong H, Hagg U 2006 Forward mandibular positioning enhances condylar adaptation in adult rats. European Journal of Orthodontics 26: 353-358. Case photos provided by Dr. Chetan V. Jayade 17
A Perspective on Forces, Tooth Movement and the SmartClip Self-Ligating Appliance System by Garland Watson, DDS, MSD Dr. Garland Watson received his MSD in Orthodontics from the University of Texas Dental Branch Graduate School of Biomedical Sciences in 1966. He has been in continuous practice of Orthodontics in Bryan/College Station Texas for 44 years. He is a visiting lecturer for the Department of Bioengineering at Texas A&M University. When I was asked to write an article on tooth movement, I was tempted to drive down to the dental branch and research vigorously whatever it was that I was going to put on paper. Instead, I visited with and consulted with professional engineers about the subject of orthodontic forces, and how they accomplished their work. One of these engineers just happens to be my brother-in-law, who is currently the recipient of my handiwork. He certainly is in a position to add his expertise as to how all this tooth movement comes about. Looking back to when I started my practice in the 60 s, it was apparent that all of the force delivery systems we used needed to be incorporated into the archwire. With the exception, of course, of the headgear and elastics, which were a universal addition to most patient s treatment. For the Orthodontist, this meant a good understanding of how force systems worked. In addition, how these systems were going to work on our patients. I distinctly remember Dr. Charles Tweed telling us to read the wires, as they tell you what is happening. So, we read a lot of wires and learned a lot about biomechanics. The application of torque was interesting and we used a special tool to create it, a torqueing arch turret. But we had no idea how much torque we needed. (Figure 1) For the most part it was pure guesswork. Figure 1: Torquing tool. 1 In the 70 s, the introduction of the pre-adjusted appliance afforded an opportunity for several different prescriptions to appear, with the intention and assumption that one size would fit all. This led us to believe that all we had to do was ligate the archwire and the work would be done for us. Unfortunately, it didn t, as time and frustration would tell. Added to that, we started bonding the brackets, which added another variable to the system in regards to placement, torque and angulation. After all, no two patients are exactly the same, and individual differences started creeping into our treatment results, compounding the problems. Some patients needed low torque in the anteriors, whereas others needed higher. Some central incisors have convex facial surfaces, where others have flat surfaces. Which, depending where we placed the bracket, altered the torque. Cuspids presented even more of a challenge, as they vary consistently. Bicuspids of different sizes and lengths are commonplace. Perhaps the greatest variable in this entire procedure is accurate placement of the bracket slot when bonding directly. I am convinced that it is almost if not impossible to get it right with direct bonding, using the current technology. I m sure I am not the only practitioner that has reached the last month of treatment, only to realize that I can t get finished without repositioning some brackets. I ll also bet that many of us have placed a lot of bends in archwires to try to get there. Many times we drop down a wire size or two to get re-engagement, further extending treatment time. It all adds up to what I call finish frustration. 18
The SmartClip Appliance System Difference But to get back to my brother-in-law, when we were discussing his treatment, he was intrigued by the SmartClip Self-Ligating Appliance System engineering and had a lot of questions. As we discussed the forces involved, he had some interesting observations. Because of the point of application of force, all forces involved are torque forces. In other words, moments or rotational forces. If we are extruding a tooth with a round or less than a full size wire, the tooth will rotate lingually or palatally. If we are tipping a tooth mesially or distally we are incorporating a moment. Figure 2: SmartClip SL3 Self-Ligating Appliance System Bracket. For bracket positioning, our practice uses the bracket placement guidelines according to Dr. Sondhi s bracket placement heights. This allows for both typical and atypical bracket placement. These charts are available from 3M Unitek. Place the brackets according to Dr. Sondhi s suggestions as far as deep, standard and open bites are concerned. The variable bracket heights in combination with Variable Prescription Orthodontics, further creates the customization of the case, and greatly enhances the wires ability to do its work. Another key treatment feature is the use of Tandem Archwires. There are several combinations of round wires that can be employed. In our practice, we often place tandem.012 NiTi wires at the bonding appointment even if full engagement of both wires is not available. It will be at the next appointment! Figure 3: Tandem archwire. 2 In addition, the low friction and inter-bracket flexibility of the wire due to the unique optional clip attachment allows for a better force system. He also commented that the application of torque is best achieved by inserting a rectangular wire as soon as possible. The point of rotation of torque has such a short moment arm that the application needs to work longer to accomplish the desired results (Torque = r F where r = moment arm or distance from pivot point and F = amount of force). Observing the progress of our patients utilizing the SmartClip bracket s self-ligation, along with custom placement of the brackets and variable torque prescriptions, has been very encouraging. The engineers tell me that the best way to consistently assure a desired result is to set up the treatment initially with the brackets in the best positions to facilitate the desired force systems. For me the only way to do that is with indirect bonding set-up procedures. We set up our cases using Dr. Anoop Sondhi s indirect bonding guidelines*. Using Variable Prescription Orthodontics (VPO), we determine from the patient s records the best torque prescription to utilize. Both the SmartClip SL3 self-ligating appliance system and Clarity SL Self-Ligating Appliance System offer a high, medium, and low torque prescription. Additionally, we offset all rotations at least 1 mm if possible but do not attempt to bond severe rotations. If there is no place to move the tooth, wait until the space is available, then bond it. 3 When rectangular wires are placed, it s important to use tie backs. Failure to do so will not allow the rotational force applied to the teeth to be effective. The ability to eliminate most of the variables of appliance fabrication is now beginning to make sense. The common variables of compliance and individual difference will never go away, but the possibility of reducing treatment time, improving patient comfort and reducing hygiene problems makes it worth while. It is exciting for me to see the advancement in orthodontics brought on by the SmartClip SL3 self-ligating appliance system. The learning curve for our team has been rewarding and we are seeing the results of incorporating a total system into our practice that is giving our patients the predictable results we want for them. * For more information on Dr. Anoop Sondhi s indirect bonding, Variable Prescription Orthodontics and Tandem Archwires, visit www.3munitek.com and 3MUnitekTraining.com, or ask your 3M Unitek Representative. 19
Save the Dates for the 2011 3M Unitek Summits February 25-26, 2011 3M Self-Ligating Appliances National Summit Fontainebleau Resort South Beach, FL In this Summit, you will hear and meet world renowned Orthodontists who are using 3M Self-Ligating Appliances in their practices. They ll share their insight into how they ve used the systems to make their staff and practices more efficient. February 25-26, 2011 Fontainebleau Resort Miami Beach, FL Innovative Self-Ligation Technology Register today at www.3munitek.com Featuring: Dr. Anoop Sondhi, Dr. Lisa Alvetro and Dr. Anmol Kalha Registration Special: Register before December 25, 2010, and receive 25% off your Summit Registration Costs. April 1-2, 2011 14th Annual Las Vegas Summit Wynn Las Vegas Nevada Managing Interdisciplinary Cases Effectively. Make plans to join us at the 14th Annual 3M Unitek Summit in Las Vegas. Learn how to use the core principles of the MBT Versatile+ Appliance System to properly prepare a case for interdisciplinary treatment and to work cooperatively toward an excellent result. April 1-2, 2011 Wynn Las Vegas Las Vegas, NV Efficient Treatment Solutions for Clinical Excellence Register today at www.3munitek.com or www.3munitektraining.com Registration Special: Register before February 1, 2011, and receive 25% off your Summit Registration Costs. CE Credits Approved PACE Program Provider FAGD/MAGD Credit: Approval does not imply acceptance by a state or provincial board of dentistry or endorsement. (8/1/2009) to (7/31/2010) 3M Unitek Orthodontic Products 2724 South Peck Road Monrovia, CA 91016 USA www.3munitek.com In U.S. and Puerto Rico: 1-800-423-4588 626-574-4000 In Canada: 1-800-443-1661 Technical Helpline: 1-800-265-1943 626-574-4577 CE Hotline: 1-800-852-1990 x4649 626-574-4649 Outside these areas, contact your local representative. Please recycle. Printed in USA. 3M 2010. All rights reserved. 012-244 1004