APOS Trends Volume I No 2 Article2

APOSASIAN PACIFICORTHODONTIC SOCIETY

Journal of the Asian Pacific Orthodontic Society

Trends in Orthodontics...Trends in Orthodontics...

Dr. Eric Liou, could you please describe your treatment philosophy?My treatment philosophy is essentially a conglomeration of two modes. First: Contemporary and second: Simplistic in approach. Basically, I believe in enmasse retraction, so naturally my technique involves in contemplating the same. Most part of my practice comprise of mechanics encompassing lever arm principles on continuous arch wires , which not only allows enmasse retraction, but also simultaneous intrusion as well, which is what required in most of cases I treat. In addition, the lever arm principle acts as a great anchor conserving modality with sound biomechanics.

Could you please elaborate more.I begin my wire sequencing with 0.014" Copper NiTi wires, and at subsequent visits, as per the requirement, I might change the wires to 0.016x0.022"NiTi wire or O.O17x 0.025" Low Friction TMA. My final wires are 0.017"x0.025" Low Friction TMA on which I begin enmasse retraction and intrusion, which typically involves lever arms and hooks 3 mm

1distal to the canine brackets (Fig. 01 ). I seldom use stainless steel wires, because I get the required resiliency from TMA wires, and the dimension of the wire is sufficient to have enough play (wire and bracket relationship) during retraction. I hardly change the wires, until complete retraction is achieved. Minor settling is taken care by second order bends in the wire or with settling elastics.

Fig.Ol Enmasse retraction of upper and lower anterior teeth with lever arms.

DR. ERIC LIOU IS RENOWNED INTERNATIONALLY FOR NUMEROUS INNOVATIONS, PROTOCOLS AND DEVELOPMENTS WITH RESPECTS TO EXCELLENCE IN CLINICAL ORTHODONTICS. IN AN EXCLUSIVE CHAT WITH DR. NARAYAN GANDEDKAR, IN TAIPEI FOR APOS TRENDS IN ORTHODONTICS, DR. LIOU SPEAKS ABOUT A RANGE OF ISSUES THAT PROVIDE ENORMOUS INFORMATION TO A CONTEMPORARY ORTHODONTIC CLINICIAN.

THE TRENDS SHOWCASE

AN INTERVIEW WITH DR. ERIC LIOU-DR. NARAYAN GANDEDKAR

DR. NARAYAN GANDEDKARis Assistant Professor, Dept. of Orthodontics & Dentofacial Orthopedics, SDM College of Dental Sciences & Hospital, Dharwad, India. He completed his Bachelor degree (BDS), SJM Dental College, Chitradurga &Masters (MDS), SDM College of Dental Sciences &Hospital, Rajiv Gandhi University of Health Sciences (RGUHS), Bangalore, Karnataka, India. He was awarded Mrs. Savadi Gold medal for securing First rank (Orthodontics) by the Rajiv Gandhi University. He recently finished Clinical &Research Fellowshipin Craniofacial Orthodontics, Chang Gung Memorial Hospital, Taipei. His research interest includes TAD’s, Orthodontic intervention in cleft lip and palate patients, Management of craniofacial syndromes, CBCT &3D application in orthodontics, Biomechanics, Biology of tooth movement. He has various publications in AJODO, Journal of Clinical Orthodontics, and World Journal of Orthodontics. He is on the review board of World Journal of Orthodontics.

DR. ERIC LIOUDDS, MS is Associate professor at Chang-Gung Memorial University, Taipei. He is the vice-chairman of department of dentistry and craniofacial orthodontics. His article won the prestigious Dewel Award of American Journal of Orthodontics and Dentofacial Orthopedics of 1998. He is on the review board of several international journals and has published several articles on dental distraction, orthopedic intrusion appliances, Alt-RAMEC, Class III case management, TAD, cleft and craniofacial syndromes. Currently he holds eight patents for his innovations. His researchinterest lies in biology of tooth movement, TAD, Bone biology etc.

Volume : 1 No. 2 - November 2010




2) I’m very much aware that your article won Dewel award for best clinical paper of 1998 for Dental Distraction (DD).DD, and has been one of the domains of your treatment philosophies. How and when did you develop the idea of DD?

Before we applied the technique of Dental Distraction on human beings, we conducted animal studies, which gave us very suppor tive conclusions both clinically as well as hisotologically. This prompted us to put forward DD application

2on human beings as well. Later on, we published our results . (Fig.02)

Fig.02 Canine distraction device is placed close to center of resistance of canine to achieve bodily movement

3) You seem to use numerous indigenous noncompliant appliances in your practice, could you throw some light on them?Over the last twenty years of my practice, what I have learnt that, patients are always interested in techniques which involve as minimal co-operation as possible, and also minimal treatment time. Hence, this compelled me to develop some of the noncompliant appliances, from which I was able to seize away the compliance factor of the patient. Maxillary protraction springs, Double hinged expander, LOMAS, Dental Distractor, Maxillary orthopedic intrusion appliance, and so on.

4) When and how did you conceptualize TAD’s?LOMAS (Lin/ Liou Orthodontic Mini Anchor System, Mondeal Medical system GMBH, Tuttlingen, Germany) was developed along with my colleague Dr. James Lin in 2003. This system has 2 different types of miniscrews to suit to the clinical scenario. A) Hook type B) Quattro type are self drilling Ti alloy that has a platform and bracket head (0.022x0.028") slot rather than bracket structure. The LOMAS hook screw works like a molar hook, and the LOMAS Quattro screw has a Lewis bracket and an auxiliary rectangular tube for the direct application of a

rectangular or a round arch wire or auxiliary lever arm. The advantage of the auxiliary rectangular tube is three dimensional

3(3D) control of a rectangular archwire . (Fig 03)

Fig.03 Lomas hook screw ( A) and Quattro screw (B) . Quattro screw is used for both insertion of lever arm and also for attachment of NiTi coil springs.

5) Dr. Liou, where do you think the TAD’s should be placed. I mean, site of placement in maxilla and mandible, and why so?I do strongly believe that the TAD’s should be placed in the non-tooth bearing area. I mean my site of placement of TAD’s are not in the inter-radicular area, but, infrazygomatic crest1>3 >4&5 for maxilla and buccal shelf area for mandible, which are rather “Play safe zone”. Our study shows that both miniscrews and teeth might be subjected to migration causing root injury

4during orthodontic treatment . (Fig.04)Fig.04 Clinical implications for miniscrew insertion in IZ crest of adults are to insert miniscrew 14-16 mm above maxillary occlusal plane and maxillary first molar, at angle of 55°-70° to maxillary occlusal plane

6) What is your approach in treating Class III individuals?Before getting on with the treatment aspect, it is very important to diagnose the problem and determine the concrete cause of Class III, of course keeping in mind the age of patient. Not only the diagnosis, but also the age is very important factor in treating a Class III individual. For a growing Class III individual, to obtain good stability, our clinical experience revealed that the timing for effective maxillary orthopedic protraction is around the onset of puberty (age 11-13). Early treatment is not recommended because of the unpredictable mandibular growth. The onset of puberty could be evaluated by using






vertebral bone age on cephalogram (CVS 2 to 3). My treatment plan is to disarticulate or loosen the circumaxillary suture by double hinged expander (Fig.05) using Alt-RAMEC protocol (Table.Ol) and subsequently protract the maxilla with protraction springs (Fig.06). The protocol is to displace the maxilla anteriorly and to disarticulate circumaxillary sutures, rather than to overexpand the maxilla6. Now we have studies,

7 8both human (Fig.07) and animal , proving that Alt-RAMEC loosens the circumaxillary sutures, not just the sutures directly articulating the maxilla, but also sutures remote to maxilla without any undue effect like bone dehiscence, root resorption (Fig.08), and fenestration of the maxillary posterior teeth where

9the expander is anchored .

Fig.05 Double hinged expander advocated for disarticulating the circumaxillary sutures

Fig.06 Maxillary protraction spring made of 0.036" TMA for protraction of the maxilla after Alt-RAMEC.

Fig. 07 3-D Illustration of circumaxillary sutural disjunction a n d S i m p l a n t P r o ™ s o f t w a r e a n a l y s i s o f zygomaticotemporal suture disjunction.

Fig. 08 Coronal and axial sections of maxillary posterior teeth showing no bone dehiscence and root resorption.






Table.Ol Protocol of the 7 Weeks of Alternate Rapid Maxillary Expansions and Constrictions (7wk-Alt-RAMEC)

7) How different is your double hinged expander from other expanders?Several types of rapid maxillary expanders have been used for maxillary protraction. They are the fan-type or hyrax-type built with two acrylic resin halves, splints, or in a hygienic design .These expanders expand the maxilla in a V-shaped manner

11with a center of rotation around the posterior nasal spine 10) . It is postulated that this would entail bone resorption behind the maxilla and consequently result in posterior displacement of

12maxilla In contrast, it is postulated as well that this would entail the circumaxillary structures such as pterygoid plates to displace the maxilla forward. These two assumptions explain why some of the clinical studies on hyrax-type expanders reported anterior displacement of maxilla, while some others reported no significant displacement or posterior displacement of maxilla. The double-hinged rapid maxillary expander (US Patent No. 6334771 Bl) is developed for a greater amount of anterior displacement of maxilla.

Its configuration is similar to a W-appliance and has two hinges of rotation It consists of a jackscrew in the center, two bolts holding the screw, a body holding the bolts at anterior and two hinges of rotation at posterior (Fig.05). The rationale for its greater amount of anterior displacement of maxilla is it expands and rotates each half of the maxilla laterally and anteriorly through the two hinges of rotation located beside the molars bilaterally. This kind of expansion entails the circumaxillary structures to displace the maxilla anteriorly with less possibility of bone resorption behind the maxillary tuberosity.

Maxillary protraction springs were developed simultaneously 1

in conjunction with double hinged expanders. was looking out for a simple wire framework, which could be anchored intraorally, tooth borne, and yet achieve the required objective. On the wake of this call, maxillary protraction springs were

developed. The springs are made with 0.036 TMA wires with single helix (Fig.06)

8) Could you please demonstrate us the fabrication of protraction spring and also how do you counter the effect on the lower molars as the protraction springs are housed on the molars.The protraction springs are constructed with 0.036" TMA wire. For pictorial representation of fabrication of protraction spring and lingual holding arch, please see (Fig.09.and Fig. 10) respectively. I usually place a lingual holding arch to counter the distal tipping of the lower molars with sufficient toe-in, and I also smoothen the double back of the lingual holding arch for easy insertion into the lingual sheath. Case illustrating the application of Alt-RAMEC and protraction springs (Fig. 11).

Fig.09 0.36" TMA wire is bent into a helix with universal plier (A &B). Two additional helices are made at either ends of the wire. The wire is given a swan neck shape on one side, for easy adaptation of the spring to the ball end hook. The longer ball end hook, approximately measuring length between first molar and first premolar, is bent into hook shape for housing the protraction spring. The smaller ball end hook is bent into L shape for anchoring the spring into lower molar tube.

Fig. 10 Construction of lingual holding arch with 0.032" TMA wire. Smoothening of double back is essential for the easy insertion.






Fig 11. Extraoral and intraoral photos showing the pre and post treatment of a growing male. Pre and post lateral cephalogram of same patient showing improvement in the midface and also correction of anterior crossbite.

9) Surgical orthodontics is a routine modality in your practice. What are the essential elements of clinical examination of the patient that you apply, and what is your protocol?I prefer to keep the clinical measurements simple and only record those measurements which give more meaning to or thoganthic surgical planning. Essential components comprises of;a) Check canting of occlusion: distance between

interpupillary line to upper canine.( Fig. 12)b) Facial midline: with softissue glabella, columella as

reference landmarks. (Fig. 12)c) Dental midlines: upper and lower dental midline with

reference to facial midline.( Fig. 12)d) Incisor show at rest and also during smile. (Fig. 12)e) Facebow transferf) Facebow transfer to the articulator.g) Model mounting on the articulator. (Fig. 13)h) Surgical treatment planningi) Model trimming and cuttingj) Fabrication of surgical stents

General rules for surgical simulation;a) Any surgical movement >= 3 mm: less than 3 mm could

be solved by orthodontic tooth movement.b) Any surgical movement is better between 5 mm to 10

mm: more than 10 mm is extremely unstable and subjected to relapse.

c) Optimal amount of surgical movement is 5 mm:

uncomplicated surgery and stable results.d) Only anterior segmental osteotomy does not need face-

bow transfer and articulator: LeFort I osteotomy or 2-jaw surgery needs face-bow transfer and articulator

e) Maxilla moves forward for 1.5-2 mm when it is impacted.f) Distance between root apex and key ridge limits the

amount of impaction.g) Distance between ramus and last molar limits the amount

of setback.h) Raums width effects stability: less width less stability due

to less bony contact surface.

i) Do not do surgical uprighting or torquing: if done, sure to invite periodontal problems. j) Do not create bony step or gap more than 2 mm: questionable bone healing. k) Do not expand maxilla more than 2 mm: palatal attached gingiva cannot be expanded Case illustrating the surgical simulation (Fig. 14)

Fig. 12 Clinical measurements taken for the orhoganthic surgical planning. Canting of the occlusion is recorded at canine and inner canthus of eye on either side. Facial midline is recorded by taking glabella, columella as reference points. Incisal show at rest and also during smile is recorded.

Fig 13 Mounting of models on articulator for accurate and precise fabrication of surgical stents.






Fig. 14 Illustration of case before surgery, model planning

and one week after surgery. Note: the model planning and

the final outcome of the surgery are exacting each other.

10) You have developed a unique way of closing wide

alveolar clefts by interdental distraction osteogenesis

(IDO) and temporary anchorage device, could you please

tell us something about them.

The closure of a wide alveolar cleft is challenging because of

the difficulty in its complete closure by using local attached

gingiva. For an alveolar cleft that is wider than a maxillary

canine, the technique of interdental distraction osteogenesis

(IDO) is used to minimize the alveolar cleft before alveolar bone 13grafting or gingivoperiosteoplasty . The guidelines for a proper

distraction site are as follows:

1. An interdental distraction site should have enough healthy

attached gingiva and oral mucosa for a primary closure

after surgery.2. The interseptal bone of an interdental distraction site should

be as high as possible and at least 3 mm in thickness. At

least 1.0 mm of alveolar bone should be preserved on

eachside of the distraction. Thin alveolar bone is subjected

to be resorption by the postoperative regional accelerated

phenomenon, which leads to root exposure and a reduction

in alveolar bone height. A reduction in alveolar bone height

will result in less volume and height of the regenerate.3. The distracted segment should contain at least 2 teeth to

ensure adequate blood supply from the adjacent gingival or

oral mucosa. (Fig 15 & 16)

I have also devised another treatment modality to reduce the

residual alveolar clefts by advocating the use of temporary

anchorage devices. (Fig 17&18)

Fig 15. Interdental distraction osteogenesis for the closure of a wide alveolar cleft with unilateral(Right) and bilateral(Left) cleft lip and palate. (A) The alveolar cleft before distraction. A transpalatal arch and fixed orthodontic appliances were placed for the presurgical orthodontic preparation. (B) The alveolar cleft was successfully approximated after the interdental distraction osteogenesis and orthodontic treatment. A lingual bonded retainer was bonded for the post-treatment retention. (C) The width of the alveolar bony defect of the cleft is shown on the predistraction radiograph. (D) The post-treatment radiograph shows that the alveolar cleft was successfully approximated and bone grafted

Fig .16 Intraoral distraction device and segmental osteotomy for the interdental distraction osteogenesis.Fig. 17 Orthodontic management of the residual bony bridge across an alveolar cleft in a 14-year-old girl with bilateral cleft lip and palate. (A) The maxillary dentition was well aligned; the orthodontic miniscrews were inserted in the infrazygomatic crests of the maxilla on both sides; and NiTi coils were used to protract the buccalteeth into the residual bony bridges. (B) The alveolar bone height of the residual bony bridges ranged from one-half to one-third of the anterior teeth root length before treatment. (C) The residual bony bridge across the alveolar clefts was approximated successfully after the treatment. (D)






The edentulous space and residual bony bridges on both sides were successfully eliminated, and the alveolar bone height was resumed on the anterior teeth.

Fig. 18 Orthodontic management of the residual alveolar cleft and residual bony bridge in a 21-year-old male patient with bilateral cleft lip and palate. At the beginning of the treatment, the buccal teeth on both sides were well aligned and protracted into the residual alveolar cleft and bony bridges by using miniscrews and NiTi coil springs. Bony defect of the residual alveolar cleft on the right side and bony defect of nasal floor and residual bony bridge on the left side. (E, F, and G) The right and left edentulous space had been closed clinically, and a pair of Ni-titanium extruding cantilever arms were using for extruding the upper anterior teeth. (H) The edentulous space, residual alveolar cleft on the right, bony defect of the nasal floor, and residual bony bridge on the left side were successfully eliminated after the treatment.

11) Yet another innovation of yours is orthopedic repositioning device, could you please throw some light on this form of treatment modality.The device for orthopedic medial repositioning is an intraoral tooth-borne distraction device. It consists of a body, a screw, and an extension arm. There are two bolts on the body for holding the screw. The fixed bolt is attached on the front of the body for holding the head of the screw. The sliding bolt rides and slides on the sliding bar of the body for holding the tail of the screw. The U shaped connector at distal end of the body is inserted the headgear tube on the molar band and secured with a 0.012-in ligature wire. The extension arm is adjusted to hook distally to the maxillary incisors so that the premaxilla is being pushed toward the midline when the device is activated. The arch wire is a track guiding the premaxilla to slide in a linear

14'15curvature direction during the orthopedic repositioning . (Fig

19 & 20)

Fig .19 The orthopedic intrusion device for premaxillary orthopedic intrusion and the assembly of the device in a clinical case.

Fig 20. The premaxillary orthopedic intrusion. The equine appearance of the premaxilla prior treatment (right), after Imonth of orthopedic intrusion (middle), (left) post orthopedic intrusion.

Dr EJW Liou, on behalf of APOS TRENDS, and its Editors - Dr. Nikhilesh Vaid & Dr. Ashish Gupta, I thank you very much for this extensive interview..........

References:1) Liou EJ, Lin JCY. Appliances, mechanics, and treatment strategies toward orthognathic -like

treatment results. In R Nanda, FA Uribe, editors: Temporary anchorage devices in orthodontics, St Louis,Missouri 2009, Mosby Elsevier, pp 167-197.

2) Liou JW, Huang CS. Rapid canine retraction through distraction of the periodontal ligament Am J Orthod Dentofacial Orthop 1998; 114:372-82

3) Lin JC, Liou EJ. A new bone screw for orthodontic anchorage. J Clin Orthod 2003: 37(12):676-681.

4) Liou EJ, Pai BC, Lin JCY: Do miniscrews remain stationary under orthodontic forces? Am J Orthod Dentofac Orthop 2004; 126; 42-47.

5) Liou EJ, Chen PS, Wang YC, et al: A CT scan study on the thickness of infrazygomatic crest of maxilla and its clinical implications for implant orthodontics. Am J Orthod Dentofac Orthop 131:352-356, 2007






6) Liou EJ. Tooth borne maxillary protraction in Class III patients. J Clin Orthod. 2005; 39:68-75.

7) Gandedkar NH, Liou Y, Liou EJW A prospective CBCT study on the opening of circumaxillary sutures by alternate rapid maxillary expansions and constrictions. Book of abstracts, 7th International Orthodontic Congress. Sydney, Australia 6-9 February 2010. World journal of orthodontics special supplement, 2010: pp 369.

8) Wang YC, Chang MS, Liou EJW. Opening of circumaxillary sutures by alternate rapid maxillary expansions and constrictions. Angle Orthod 79;230-234, 2009

9) Gandedkar NH, Liou YJ, Liou EJW. Impact of alternate rapid maxillary expansions and constrictions on alveolar bone dehiscence: A CBCT study. Book of abstracts, 110th annual meeting, American association of orthodontists, Washington D C, April 30 - May 4, 2010.

10) Vardimon AD, Brosh T, Spiegler A, Lieberman M, Pitaru S.Rapid palatal expansion: Part 1. Mineralization pattern of the midpalatal suture in cats. Am J Orthod Dentofacial Orthop 1998; 113:371-378.

11) Braun S, Bottrel JA, Lee KG, Lunazzi JJ, Legan HL. The biomechanics of rapid maxillary sutural expansion. Am J Orthod Dentofac Orthop 2000; 118:257-261.

12) Lee KG, Ryu YK, Park YC, Rudolph DJ. A study of holographic interferometry on the initial reaction of maxillofacial complex during protraction. Am J Orthod Dentofac Orthop 1997; 111:623-632.

13) Liou EJ, Chen KT, Chen RY, Huang CS. Interdental distraction osteogenesis and rapid orthodontic tooth movement: A novel approach to approximate wide alveolar cleft or bony defect. Plast Reconstr Surg 2000; 105:1262-1272.

14) Liou EJ, Chen KT. New orthodontic and orthopedic managements on the premaxillary deformities in patients with bilateral cleft before alveolar bone grafting. Ann Coll Surg Hong Kong.2003; 7:73-82.

15) Liou E.J, Chen, P.K.T, Huang C. S, Chen,Y.R. Orthopedic intrusion of premaxilla with distraction devices before alveolar bone grafting in patients with bilateral cleft lip and palate. Plast. Reconstr. Surg. 113:818, 2004.



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