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n Evidence-Based Analysis of Periodontallyccelerated Orthodontic and Osteogenicechniques: A Synthesis of Scientificerspectives. Thomas Wilcko, William M. Wilcko, and Nabil F. Bissada
Interdisciplinary orthodontic tooth movement (OTM) can synthesize tis-
sue engineering principles with periodontal regenerative surgery to create rapid
orthodontic tooth movement and reduce side effects like root resorption, relapse,
inadequate basal bone, and bacterial time-load factors (ie, infection). Normal me-
tabolism seen in a natural healing response is accelerated resulting in a more
stable clinical outcome. Specifically, modern computed tomographic imaging sug-
gests what were thought be “bony blocks” undergo demineralization both on the
surface and within the alveolar bone proper (reversible osteopenia). Periodontal
analysis shows that with demineralization the remaining collagenous soft tissue
matrix of the bone is transported with the root in the direction of the movement.
When retained in the desired position the matrix remineralizes demonstrating
malleability of the alveolus previously thought to be unattainable. This natural
demineralization-remineralization phenomenon appears fairly complete in adoles-
cents albeit benignly less complete in adults. The new interpretation of the rapid
movement as “bone matrix transportation” has made it possible to design a
surgical approach, which permits extraction space closure in 3 to 4 weeks. This
protocol allows conventional OTM 300% to 400% faster, increases the envelope of
movement 2- to 3-fold and alveolar augmentation (periodontally accelerated os-
teogenic orthodontics or PAOO), and increases alveolar volume providing an al-
ternative to bicuspid extraction. (Semin Orthod 2008;14:305-316.) © 2008 Published
by Elsevier Inc.
pleaprppittosd
ic
he 21st century is referred to as the Centuryof the Biologist and the dentofacial dimen-
ion of the orthodontic specialty is a front stage
Clinical Associate Professor of Periodontics, Case Western Reserveniversity. School of Dental Medicine, Cleveland, OH; Consultant,aval Dental Center, Bethesda, MD.
Adjunct Assistant Professor of Orthodontics and Dentofacial Ortho-edics, Boston University, Henry M. Goldman School of Dental Medicine,oston, MA; Consultant, Naval Dental Center, Bethesda, MD.
Professor and Chairman, Department of Periodontics & Affiliatedkeletal Research Center, Case Western Reserve University School of Dentaledicine, Cleveland, OH.
Address correspondence to Nabil F. Bissada, DDS, MSD, Caseestern University, School of Dental Medicine, 10900 Euclid Ave-
ue, Cleveland, OH 44106. Phone: (216) 368-6757; Fax: (216)68-3204; E-mail: [email protected]
© 2008 Published by Elsevier Inc.1073-8746/08/1404-0$30.00/0
tdoi:10.1053/j.sodo.2008.07.007
Seminars in Orthodontics, Vol 14, No
layer in the script of scientific progress. Over theast two decades, the refinements of an attempt tongineer an “optimal response” of alveolar bone topplied “optimal force” has propelled both theeriodontal and the orthodontic specialties di-ectly into the field of surgical dentofacial ortho-edics the way distraction osteogenesis and theublication of the human genome have made clin-
cal medical orthopedics more biologically sophis-icated in its mechanical therapeutic manipula-ion. Specifically, the molecular dynamics ofsteogenesis in stressed bone defines pathwaysimilar to steady-state homologues not yet fullyefined.
We would suggest that most salient in thisnevitable progress, the spirit of interdisciplinaryollaboration in the orthodontic specialty has
aken traditional orthodontic tooth movement3054 (December), 2008: pp 305-316
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306 Wilcko, Wilcko, and Bissada
OTM) protocols and synthesized periodontalissue engineering and regenerative surgery, notnly a method of rapid orthodontic tooth move-ent, but also provided every young clinicianith a protocol that also reduces side effects likeoot resorption, relapse, inadequate basal bone,nd bacterial time/load factors, that is, caries andnfection. Interestingly, on a clinical level, this in-ovation elicits a latent enthusiasm for the treat-ent in both adolescents and population cohorts
hat previously avoided OTM.The commonly held notion that preexisting
lveolar volume is immutable has placed sub-tantial limitations on the amount of toothovement thought to be safely achievable and
till provide a stable result. For well over fourecades the Department of Orthodontics at theniversity of Washington has collected diagnos-
ic records on more than 600 patients that were0 or more years into retention.1 After 10 yearsf retention, satisfactory mandibular alignmentas maintained in less than 30% of patients.elapse was generally accompanied by a de-rease in arch length and width. Interestingly,othe and coworkers in a study of mandibular
ncisor relapse have reported that patients withhinner mandibular cortices after debondingre at increased risk for dental relapse.2
The new technique described here provides anncreased net alveolar volume after orthodonticreatment. This is called the periodontally acceler-ted osteogenic orthodontics (PAOO) technique.t is a combination of a selective decortication-acilitated orthodontic technique and alveolar aug-
entation.3-6 With this technique, one is no longert the mercy of the preexisting alveolar volume,nd teeth can be moved 2 to 3 times further in1/3] to [1/4] the time required for traditionalrthodontic therapy.3-6 It can be used to treatoderate to severe malocclusions in both adoles-
ents and adults and can reduce the need forxtractions. Except for severe Class III skeletal dys-lasia, PAOO can replace some orthognathic sur-ery, and because of the low morbidity, patients 11o 78 years old have been treated with markediologic impunity.
istorical Review
nly the biologic rationale and evidence-basederacity is new. Rudimentary surgical interven-
ion to affect the alveolar housing and speed pooth movement has been used in various formsor more than a hundred years. It was Heinrichöle’s publication in 1959,7 however, that set the
tage for the subsequent evolution of refinedecortication-facilitated orthodontics. Köle be-
ieved that it was the continuity and thickness ofhe denser layer of cortical bone that offered the
ost resistance to tooth movement. He theo-ized that by disrupting the continuity of thisortical layer of bone that he was actually creat-ng and moving segments of bone in which theeeth were embedded. He believed that theseutlined blocks of bone could be moved rapidlynd somewhat independently of each other be-ause they were connected by only less denseedullary bone, which would act as the nutritive
edicle and maintain the vitality of the peri-dontium. The blocks of bone were outlinedsing vertical interradicular corticotomy cutsoth facially and lingually and these were joined0 mm supra-apically with an osteotomy cuthrough the entire thickness of the alveolus.Note: The modern refined selective alveolarecortication [SAD] and PAOO protocols ex-licitly contraindicate this surgical element.)rom Köle’s work arose the term “bony block” toescribe the suspected mode of movement fol-
owing corticotomy surgery, a more morbid pro-edure than modern, refined modes of therapyiscussed here.
Köle reported that the major active toothovements were accomplished in 6 to 12 weeks.
t is important to note that most of the move-ents described by Köle were relatively grossovements accomplished with borderline or-
hopedic forces delivered through removableppliances fitted with adjustable screws. He ad-ressed most movements including space clos-
ng. In accomplishing space closing he utilized aedge-shaped ostectomy at the extraction site
hus, apparently, leaving only the interseptalayer of bone over the proximal surfaces of thedjacent teeth. In his diagrams, it does appearhat he extended the ostectomy beyond the apexf the canine, but left the interseptal bone intactver the apical one-third of the second bicuspid.uriously, this would have resulted in a thinner
ayer of bone being left on the distal aspect ofhe canine that was to be distalized than on the
esial aspect of the second bicuspid.Köle reported that after treatment there was no
eriodontal pocket formation. He also reported
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307Evidence-Based Analysis
hat at 6 months after treatment vitality testing of theeeth was always positive and radiographically thereas no evidence of root resorption. Over time the
upra-apical connecting osteotomy cuts used byöle were replaced with corticotomy cuts. Wherextraction/space closing was involved it would ap-ear that the vertical ostectomy was typically re-
ained. Gantes and coworkers in 1990 reported onorticotomy-facilitated orthodontics in five adultatients in whom space closing was attempted witherely orthodontic forces.8 The mean treatment
ime for these patients was 14.8 months, with theistalization of the canines being mostly com-leted in 7 months. The mean treatment time for
he traditional orthodontic control group was 28.3onths. The surgery included circumscribing cor-
icotomy cuts both facially and lingually aroundhe six upper anterior teeth. The upper first bicus-ids were removed and the bone over the extrac-
ion sockets was removed both buccally and lin-ually. It would appear that Gantes and coworkersid not thin the interseptal bone on the distal of
he canine to be distalized and the 7 months ofanine retraction suggest a failure to exploit fullse of an induced therapeutic decalcification. Thisould account for the contrast between the rootesorption he reported and the notable absence ofesorption subsequently reported by other, moreodern researchers.The interpretation of the rapid tooth move-
ent being attributable to “bony block” move-ent prevailed in the reported literature until
001 when Wilcko and coworkers3 reported thatn a surface computed tomographic (CT) scanvaluation of selectively decorticated patients itas discovered that the rapid tooth movementas not the result of bony block movement, butather to a transient localized demineralization-emineralization phenomenon in the bony alve-lar housing consistent with the wound healingattern of the regional acceleratory phenome-on (RAP), developed by Frost and Jee andescribed in the periodontal literature by Yaffend coworkers9 The demineralization of the al-eolar housing over the root surfaces apparentlyeaves the collagenous soft tissue matrix of theone, which can be carried with the root surfacend then remineralizes following the comple-ion of the orthodontic treatment. Ferguson andoworkers have further defined this to be ansteopenic process.5,6 Wilcko and coworkers
ave also demonstrated that it is not the design sf the selective alveolar decortication that is re-ponsible for the rapid tooth movement4 butather the degree of tissue metabolic perturba-ion per se.
ase Reports
aterials and Methods
he surgeries were performed under IV seda-ion and local anesthesia. Patients 1 and 2 wereure SAD-facilitated orthodontic cases, and pa-ients 3 and 4 were PAOO cases. There was no
obilization of any bony segments. The orth-dontic adjustments were made at 2-week inter-als and removable retainers were utilized afterebonding. The CT scans were performed withospital-based high-resolution scanners. A waxite was used to slightly separate the maxilla andandible.
atient 1 (Decortication-Facilitatedrthodontics in an Adolescent)
male, age 14, presented with minor to moderatenterior crowding and a Class I molar relationship.he total treatment time from bracketing to de-racketing was 3 months 2 weeks. Following theeflection of full thickness flaps, circumscribingorticotomy cuts were performed both labially andingually around the six upper and six lower ante-ior teeth (Fig 1). The posterior teeth were utilizedor anchorage.
Pretreatment, posttreatment, and 2-year re-ention surface CT scans of the lower arch areeen in Fig 2. At 2.5 months after debracketing it
igure 1. Patient 1: Male, age 14, circumscribing de-ortication, mandibular cuspid to cuspid teeth (teethumbers 22-27). Dibart 2007, reprinted with permis-
ion. (Color version of figure is available online.)
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308 Wilcko, Wilcko, and Bissada
s very apparent that the integrity of the outlinedony blocks was lost. There is the appearance oflmost a complete lack of mineralized bone overoth the labial and the lingual root surfaces ofhe treated teeth, but the osseous organic matrixs intact. At 2 years retention, however, the alve-lar housing over both the labial and the lingualoot surfaces has completely reappeared.
These findings are more indicative of a demi-eralization-remineralization phenomenon con-istent with RAP and certainly not bony blockovement. The most profound demineraliza-
ion is seen in close proximity to the corticotomyuts. No apparent demineralization can be seenpproximately one tooth distant from the near-st corticotomy cut indicating the specific ther-peutic range of the regional effect.
atient 2 (Decortication-Facilitatedrthodontics in an Adult)
female, age 39, presented with moderatenterior crowding and a Class I molar relation-hip. The total treatment time from bracket-ng to debracketing was 4 months 2 weeks.ollowing full thickness flap reflection circum-cribing SAD cuts were performed both labi-
igure 2. (A,B,C) Patient 1 (adolescent): Labial imaomputed tomographic scans of lower arch, anterior,lization-remineralization phenomenon. Note transieneprinted with permission). (D,E,F) Patient 1 (adoesorption at “tension side” (lower lingual aspect) ofemonstrate lingual cortical bone regeneration.
lly (Fig 3) and lingually around the six lower o
nterior teeth, but only on the labials of theix upper anterior teeth. The posterior teethere used for anchorage.
A comparison of pretreatment, posttreat-ent, 2.5 years’ retention, and 11.5 years’ reten-
ion surface CT scans can be seen in Fig 4. Theres no indication of bony block movement in thiseries of CT scans. In the postdebracketing scanhere appears to be an absence of mineralized
, pretreatment, posttreatment, and retention surfacelingual views. The appearance is that of a deminer-
calcification but fully reversible alveolus (Dibart 2007,nt): Lingual imaging: Note that reversible alveolarr incisor proclination and regeneration 2 years later
igure 3. Patient 2: Female, age 39, circumscribingecortication, mandibular cuspid to cupid teeth (teethumbers 22-27). (Color version of figure is available
gingandt de
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309Evidence-Based Analysis
one over the labial surfaces of the roots of theower anterior teeth in close approximation tohere the circumscribing corticotomy cuts hadeen made. In the 2.5 years’ retention surfaceT scans there appears to be a return of the
ayer of mineralized bone over the roots of theower anterior teeth but at a slightly reducedeight in comparison to the pretreatment CTcan. At 11.5 years’ retention the height of therestal bone is still somewhat reduced in com-arison to the pretreatment CT scan. This alsoppears to be a demineralization-remineraliza-ion phenomenon, but not quite complete aseen in adolescent patient 1.
atient 3 (PAOO Treatment for Dentoalveolarugmentation)
male, age 23, presented with Class I molarnd canine relationships, severe upper andower crowding, severe upper arch constric-ion in the anterior and bicuspid areas, andilateral crossbites in the anterior and poste-
igure 4. Pretreatment and posttreatment surface comnterior view demonstrates the demineralization-remican demonstrates thin �washboard� alveolar labial cacilitated orthodontic therapy with fixed appliance
ineralized bone over the root prominences of the lowo be partial remineralization of the alveolar housingomparison to the pretreatment (CT) scan. (D) At 11.5o be somewhat reduced in comparison to the pretre
ior areas. It was estimated that the length of a
reatment utilizing traditional orthodonticsould be 2 to 2.5 years. The patient opted for
he PAOO treatment and his case was com-leted in 6 months 2 weeks from bracketing toebracketing. The pretreatment and 2.5 years’etention photographs of the palate can beeen in Fig 5A and B, respectively.
The PAOO surgery was performed during theeek following the bracketing and archwire ac-
ivation. Since all of the teeth would be under-oing movement, selective alveolar decortica-ion was performed both facially and linguallyround all of the remaining upper and lowereeth utilizing circumscribing corticotomy cutsnd intramarrow perforations. Note the sparse-ess of the bone on the labial (Fig 6A) and
ingual aspects (Fig 6B) of the lower anterioreeth. The activated bone and exposed root sur-aces were then covered with the bone grafting
aterial (Fig 6C). The archwires were advancedapidly with the adjustments being made at 2-weekntervals. Since most of the constriction in the upper
ed tomographic (CT) scans of lower arch in an adult;lization phenomenon. (A) Patient 2 pretreatment CTx. (B) Panel illustrates the effects of decortication-
onth after debonding. Note the apparent lack ofnterior teeth. (C) At 2.5 years retention there appearsthe root prominences of the lower anterior teeth in
rs retention the height of the crestal bone still appearsnt (CT) scan.
putneraorte
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rch was mesial to the molars, it was possible to
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310 Wilcko, Wilcko, and Bissada
xpand and round out the upper arch with the usef only archwires in approximately 12 weeks. Inter-stingly, there was no significant opening of the mid-alatal suture during treatment. This would suggesthe alveolus per se may be considered an operativerthopedic entity from a “whole bone perspective”
rrespective of the periodontal ligament (PDL) orircum-maxillary sutures.
The pretreatment CT scans in Figs 7 and 8learly show the sparcity of bone on the labialnd lingual aspects of the roots that was con-rmed following the reflection of the full thick-ess flaps. This was especially evident in the
ower anterior area (Fig 6A, B) where there wastall thin symphysis and where significant bony
igure 5. (A) Patient 3: Male, age 23, before PAOOrafts) palatal view. Note thinness of palatal alveolusfter debonding. (Color version of figure is available
igure 6. Demonstration of the PAOO (decorticatioatient with thin alveolar cortices at the lower incisoecortication (SAD) from left to right lower second mf lower arch. (B) Bone activation (SAD), lingual viewhe lingual root prominences of the lower central incC) Bone grafting material (demineralized bone matrllograft, or DFDBA) with a popular (mineral conten
one. (Color version of figure is available online.)ehiscences were found. Not only were bonyehiscences found on the labial aspects of theoots, but also on the lingual aspect of the lowerentral incisors where they extended almost tohe apices of these two teeth. It was noted in the.5 years’ retention surface CT scans in Figs 7nd 8 that the labial and lingual root promi-ences were no longer evident and there nowppears to be ample bone over the roots of theeeth both labially and lingually. This was con-rmed when this case was reentered using full
hickness flaps and bone biopsies removed overoot surfaces where there had previously beeno bone.3 As a result of the alveolar augmenta-
ion the roots of the lower anterior teeth were
ment (decortication and tooth movement into bonecuspid area. (B) Patient 3: Thirty months (2.5 years)
e.)
lus bone graft) procedure in an adult orthodontic) Patient 3: Bone is activated with selective alveolarto second molar (teeth numbers 18–31), facial view
wer arch. Note that there are alveolar dehiscences onthat extend almost to the apices of these two teeth.DBM; also know as demineralized freeze-dried bone
y) xenograft extender placed over the SAD-activated
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311Evidence-Based Analysis
hen confined labially and lingually between twoninterrupted layers of bone. It is suggested that
he alveolar augmentation eliminated the den-oalveolar deficiency that was created when theeeth were tipped labially.
igure 7. Patient 3. Maxillary arch computed tomocans before PAOO treatment, left oblique view. (Betention. Note increased volume of stable bone ovefore PAOO treatment, left oblique view. (D) Metention. Note increased volume of stable bone overthodontics.
igure 8. Patient 3. Before and after PAOO treatmeingual alveolus demonstrate that notable increases inppliances are removed and after about 7 months o
dontally accelerated osteogenic orthodontics.atient 4 (PAOO Treatment with a Bicuspidxtraction Protocol)
male, age 14, presented with a Class II molar mal-cclusion with the upper canines displaced and
hic (CT) scans. (A) Maxillary alveolus surface CTaxillary alveolus surface CT scans after 2.5 years ofe roots. (C) Mandibular alveolus surface CT scans
bular alveolus surface CT scans after 2.5 years ofroots. PAOO, periodontally accelerated osteogenic
urface computed tomographic scans of mandibularlus volume are evident as soon as 2 months after fixedelerated orthodontic tooth movement. PAOO, peri-
grap) Mer thandir the
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312 Wilcko, Wilcko, and Bissada
rowded out of the arch superiorly. In the lower archAD was performed both labially and linguallyround the six lower anterior teeth, the lower poste-ior teeth being used for anchorage. In the upperrch the alveolar bone was activated in a similar fash-on around the six upper anterior teeth. The upperrst bicuspids were then removed and ostectomieserformed at the extraction sites. The ostectomiesxtended almost to the apices of the canines and theone was dramatically thinned on the distal circum-erences, midfacial to midlingual, of the roots of theanines (Fig 9A). The activated bone was then cov-red with the bone-grafting material (Fig 9B).
At 1 month after surgery, the adjustable screwetraction device was inserted (Fig 10A). The patientdjusted this device at home and in 3 weeks the spacelosing had mostly been completed (Fig 10B). Thease was then brought to completion with archwireherapy and traditional orthodontic forces. The total
igure 9. (A) Patient 4: Male, age 13, selective alveopper left to second molar (tooth 15). (B) Grafting mstectomy site. Dibart 2007, reprinted with permissio
igure 10. (A) Retraction device inserted. (B) Thre
eprinted with permission. (Color version of figure is avaiAOO treatment time from bracketing to debrack-ting was 6 months.
Pretreatment and 10.5 years’ retention sur-ace CT scans of the upper arch are shown in Fig1. The increase in the alveolar volume is readilypparent. The extraction sites of the upper firsticuspids were consolidated with the alveolarugmentation. This case has remained stablend there has been no reopening of the closedpaces. Furthermore, it demonstrates how wellonventional orthodontic and dentofacial ortho-edic forces can be employed without significantlteration of one’s favorite OTM clinical proto-ol. Only the response is reengineered.
iscussion
he stable clinical outcomes demonstrated in thisrticle owe more to the orchestration of conven-
ecortication, upper right second molar (tooth 2 torial being placed over the activated bone and in theolor version of figure is available online.)
eeks after retraction device activation. Dibart 2007,
lar date
e w
lable online.)
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313Evidence-Based Analysis
ional, well-accepted traditional techniques than toevolutionary materials that have defined orth-dontic progress in the past. It is the humility ofhe clinician-scientist and his or her willingness tombrace concepts from sister sciences that willontinue to lead us to more evolutionary treat-ent refinements for our patients. For example,
n adolescent patient 1, where the corticotomy-acilitated orthodontics was utilized to accomplishdecrowding,” the pretreatment, posttreatment,nd 2 years’ retention surface CT scans are highlyuggestive of a natural but accelerated metabolism,demineralization-remineralization phenomenont work (Fig 2). The remineralization in this ado-escent appears to be rather complete. It is sug-ested, based on modern scientific biological con-epts and anatomical imaging innovations, thatfter the relatively thin alveolar housing over theabial and lingual root surfaces undergoes demi-eralization, the collagenous soft tissue matrix of
he bone remains and can consequently be readilyransported with the root surfaces, “bone matrixransportation.”
When retained in the desired positioning theollagenous soft tissue matrix will remineralizeith time. This same type of process appears toe at work in adult patient 2, albeit slightly lessomplete, yet remains within a safe, clinicallyormal range. It is suggested that this is merely
ndicative of the difference in the vitality andhus recuperative potential of the adult versusdolescent tissues. Interestingly, Fuhrmann hashown that after traditional orthodontic therapy
igure 11. Pretreatment and 10-year retention surfacen bicuspid extraction treatment the stability and amoevere maxillary “arch length deficiency” and ostenshanical protocol. (B) Panel shows that PAOO treareatment protocols and results in stable alveolarsteogenic orthodontics.
n adults there is also bony dehiscence forma- a
ion over the roots that only partially resolvesuring retention.10 Even at 3 years’ retention heoted significant bony dehiscence that had notepaired itself, most notably on the facial aspectf the lower anterior teeth. Thus, any assessmentf presumptive deleterious bone effects of OTMust prudently await a 2- to 3-year period. In
ight of the authors’ clinical studies it wouldeem that previous criticism of orthodontic ef-ects on the alveolus might have been impetuousr premature considering the state of imagingcience at the time.
To adapt this scenario to extraction space clos-ng would merely require that only a thin layer ofone be left over the root surface in the directionf the intended tooth movement. In this manner,one matrix transportation can be also utilized toapidly close spaces. After a 2-week postoperativeaiting period to permit demineralization, spacesan be closed in 3 to 4 weeks with orthopedicorces or in 6 to 8 weeks with efficient orthodonticorces. This would seemingly add validity to Köle’slaims of being able to complete most major move-ents in 6 to 12 weeks.7
SAD-facilitated orthodontics is a physiologi-ally driven process, and an uninterrupted vas-ular supply to the operated areas is critical inaintaining the vitality of the hard and soft tissues.
Mobilization” of any outlined single-tooth blocksf bone (luxation) is absolutely contraindicatednd can lead to intrapulpal and intraosseousorbidity and will not increase the distance that
he tooth can be moved. “Green-stick fracturing”
scans; labial view of upper arch demonstrate that evenf augmented alveolar bone is stable. (A) Panel shows
need for bicuspid extraction in a traditional biome-t is compatible with traditional bicuspid extractiona decade later. PAOO, periodontally accelerated
CTunt oibletmenform
nd luxation of small dentoalveolar segments
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314 Wilcko, Wilcko, and Bissada
ill serve no useful purpose since these seg-ents will lose their structural integrity as a
esult of the demineralization associated withhe osteopenia. Additionally, the luxation caneopardize the integrity of the neurovascularundle exiting the apex of the teeth and result
n devitalization.Sebaoun and coworkers have analyzed the alve-
lar and periodontal response to selective alveolarecortication as a function of time and proximityo the injury in a rat model.6,11 Since traditionalrthodontic tooth movement per se will in itselftimulate a mild RAP response, tooth movementas thus intentionally not included in the experi-ental design. The dynamics of the periodontium
hange in response to the decortication injuryould thus be clarified.
Sebaoun and coworkers reported that selec-ive alveolar decortication injury resulted in anverwhelming activating stimulus for both the cat-bolic process (resorption response) and the ana-olic process (formation response) in the peri-dontium. This bone modeling behavior peakedt 3 weeks after decortication surgery at which timehe catabolic response (osteoclastic count) andnabolic response (apposition width and rate)ere 3-fold higher. Additionally, adjacent to the
njury the calcified spongiosa content of the alve-lar bone decreased 2-fold and the PDL surface
ncreased by 2-fold. Thus, there was a dramaticncrease in the tissue turnover by the third weekfter decortication surgery, which dissipated toormal steady state by 11 weeks after surgery. The
ncreased bone turnover was localized to the areammediately adjacent to the injury. These resultsre the first histologic and systemic evidence toupport the concept hypothesized by Wilcko andoworkers3,4 that SAD facilitates orthodontic toothovement as a result of a demineralization-remi-eralization phenomenon rather than by bonylock movement. Selective alveolar decorticationesults in a transient osteopenia and increased tis-ue turnover, the degree of which is directly com-ensurate with the intensity and proximity of the
urgical physiologic insult. This is a condition thatavors tooth movement with reduced root resorp-ion. The PDL activity is enhanced by the decorti-ation surgery, but it is the spongiosa that mostikely plays the dominant role in rapid tooth move-
ent. This may also have a positive impact onosttreatment settling and stability. Even though
he osteopenia is a transient condition, it is sur- p
ised that tooth movement perpetuates the decal-ified condition in the healthy alveolus.
There are numerous advantages in combininghe modified corticotomy-facilitated orthodonticsith alveolar augmentation. The most obvious is
hat we no longer need to be solely at the mercy ofhe preexisting alveolar volume and shape. Thelveolus can now be reshaped and enlarged toccommodate the straightened teeth in their newositioning. The pretreatment and 2.5 years’ re-
ention surface CT scans of patient 3 demonstratehis (Figs 7, 8). With adequate reflection of theaps this increase in bony volume can, to at least
ome extent, also impact on the shape and volumef the coronal aspect of the basal bone. In thisespect, we are not only impacting on the dentoal-eolar aspect, but also on the alveolar skeletal as-ect. Since there is a 2- to 3-fold increase in theistance that the teeth can be moved, this obvi-usly translates to a dramatic reduction in theeed for extractions and perhaps even some or-
hognathic surgery.From a basic science perspective, what is most
mpressive is the manifest ability of OTM withAOO to increase alveolar volume for ample alve-lar support for the roots of the teeth even in theesolution of severely crowded situations as seen inatient 3. Whereas 5 mm of crowding is typicallyonsidered the limit of overlapping that can beatisfactorily addressed with traditional orthodon-ics this can easily be extended to 10 to 12 mm ofrowding if the PAOO technique is utilized. Thisncrease in the limits of orthodontic tooth move-
ent can also be seen in other movements such asxtrusion and intrusion.5,6 This ability to moveeeth a much greater distance and yet provide forn expanded alveolar base and increased alveolarolume to support the straightened teeth makes itossible to treat certain selected cases that couldave previously only been adequately addressedith orthognathic surgery. The alveolar augmen-
ation can correct the dentoalveolar defecting thatresumptively results when the teeth are tipped
abially and can also provide for a degree of subtleacial “morphing.”
Overcompression of the periodontal ligamentan lead to hyalinization necrosis, the removal ofhich can be associated with root resorption. In anvaluation of the PAOO data base, Machado et aleported a 1.1 millimeter reduction in apical rootesorption of the maxillary central incisors in com-
arison to traditional orthodontics.12
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315Evidence-Based Analysis
As concerns stability, Ferguson states, “PAOOas contributed greater stability of orthodonticlinical outcomes and less relapse.” Summariz-ng he states, “immediate post orthodontic treat-
ent results following nonextraction therapyre statistically the same with or without PAOO.owever, during retention, the clinical out-
omes of PAOO patients improved and did notemonstrate relapse.”6
Murphy, synthesizing emerging concepts in cellnd molecular biology, has used the term “in vivoissue engineering” to further define the ability to
orph bone with orthodontic tooth movementone in conjunction with periodontal bone activa-ion and alveolar augmentation.13 He goes on totate that even though the alveolar bone does existt the grace of the radicular surfaces of the teeth,s explained by functional and spatial matrix hy-otheses of Moss and Singh, respectively,14,15 it isvident that new regional phenotypes can be epi-enetically reengineered by moving teeth throughhealing bone graft, and thus, redefine or rees-
ablish original morphotype. He also suggests thathe ability to readily reshape the alveolar housingnd simultaneously increase the alveolar volumeay impact on the subjacent bone and provide for
ome degree of facial recontouring.Very frequently there are preexisting alveolar
nadequacies such as fenestrations and dehis-ences over the root surfaces. As long as the rooturfaces in these defects are vital and as long as thereas been no apical epithelial migration, these alveo-
ar deficiencies can be corrected with the alveolarugmentation.3-6 Only resorbable grafting materi-ls are utilized. Medications that reduce the turn-ver rate of the bone and increase calcium uptakean potentially be problematic. The bisphospho-ates, and perhaps even some calcium nutritionalupplements, would fall into this category. Addi-ionally, we believe the osteopenia that facilitateshe tooth movement is a sterile inflammatory pro-ess and certain medications especially the nonste-oidal anti-inflammatory drugs (NSAIDs) couldounteract this. Defining the inflammatory path-ays that could be contributing to the underlyingone physiology that impact this process is an area
n need of considerable research.
ummary and Conclusions
oncerning the mode of movement, this is a tech-
ique that requires the demineralization of a rel- ntively thin layer of bone on the surface of the rootf the tooth in the direction of the intended move-ent. This transient, reversible demineralization
osteopenia) of the thin layer of bone permits theoot of the tooth to carry the demineralized col-agenous matrix of the bone with it. At the comple-ion of the tooth movement the remaining deminer-lized collagenous bony matrix will remineralize.he surface CT scan analyses of patients 1 and 2ould suggest that this remineralization process isore complete in adolescents than in adults. It is
uggested that this is most likely attributable to thencreased vitality and thus recuperative potential ofhe bone in the younger patients. The increase in theate of bone turnover of the osteopenic process likelyssists in the settling process after debracketing andn doing so contributes to improved stability duringetention.
The fact that the teeth can be moved moreapidly, thus resulting in shortened treatmentimes, is certainly advantageous to the patient’seriodontal health because less time in fixed ap-liances reduces patient “burnout” and substan-
ially reduces the time available for relatively benignommensal bacterial biofilms to assume qualitativehanges and convert to a destructive cytotoxic“periodontopathic”) potential often seen whenxed appliances have remained on the teeth forore than 2 to 3 years. The significance of the
ncrease of the rate of tooth movement, however,ales in comparison to the fact that the teeth cane moved two to three times further than would beossible with traditional orthodontics alone, and
hat the cases can be completed with an increasedlveolar bone volume. This increased alveolar vol-me can provide for a more intact periodontium,decreased need for extractions, a degree of facial
eshaping, and an increase in the bony support foroth the teeth and the overlying and soft tissues.erguson and coworkers have suggested that the
ncreased stability provided by PAOO may be dueo “loss of tissue memory from high tissue turnoverf the periodontium, as well as increased thicknessf the alveolar cortices from the augmentationrafting.”6 The ability to increase the posttreat-ent alveolar volume and cover vital root surfaces
an result in the repair of preexisting alveolar de-iscences over root prominences and lessen the
ikelihood of new dehiscence formation, whichan be a contributing factor to gingival recession.
From an esthetic perspective the PAOO tech-
ique not only addresses tooth alignment, but
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316 Wilcko, Wilcko, and Bissada
lso facial features and, as such, is truly in vivoissue engineering. With a combination of bothn-office periodontal surgery and orthodonticreatment, we can now more routinely addresshe esthetics of the entire lower face. The PAOOechnique requires the utilization of numerous
odified diagnostic and treatment parameters,ut once these are mastered the orthodontistas a powerful new treatment option to offer hisr her patients. With the increasing number ofdults considering orthodontic treatment, theropensity for adults and even some nongrow-
ng adolescents for periodontal problems, theAOO technique can be an especially attractive
reatment option and be a “win-win” situationor both the orthodontist and the patient.
eferences1. Little RM: Stability and relapse of dental arch alignment, in
Burstone CJ, Nanda R (eds): Retention and Stability inOrthodontics. Philadelphia, Saunders, 1993:97-106
2. Rothe LE, Bollen RM, Herring SW, et al: Trabecular andcortical bone as risk factors for orthodontic relapse. Am JOrthod Dentofacial Orthop 130:476-484, 2006
3. Wilcko WM, Wilcko MT, Bouquot JE, et al: Rapid orth-odontics with alveolar reshaping: two case reports of de-crowding. Int J Periodontics Restorative Dent 21:9-19, 2001
4. Wilcko WM, Ferguson DJ, Bouquot JE, et al: Rapid orth-odontic decrowding with alveolar augmentation: casereport. World J Orthodont 4:197-505, 2003
5. Ferguson DJ, Wilcko WM, Wilcko MT: Selective alveolardecortication for rapid surgical-orthodontic resolution
of skeletal malocclusion treatment, in Bell WE, GuerreroC (eds): Distraction Osteogenesis of the Facial Skeleton.Hamilton, BC, Decker, 2006:199-203
6. Wilcko MT, Wilcko WM, Marquez MG, et al: Chapter 4:The contributions of periodontics to orthodontic ther-apy, in Dibart S (ed): Practical Advanced PeriodontalSurgery. Ames, IA, Wiley Blackwell, 2007:23-50
7. Köle H: Surgical operations of the alveolar ridge tocorrect occlusal abnormalities. Oral Surg Oral Med OralPathol 12:515-529, 1959
8. Gantes B, Rathbun E, Anholm M: Effects on the peri-odontium following corticotomy-facilitated orthodon-tics: case reports. J Periodontol 61:234-238, 1990
9. Yaffe A, Fine N, Binderman I: Regional accelerated phe-nomenon in the mandible following mucoperiostealflap surgery. J Periodontal 65:79-83, 1994
0. Fuhrmann R: Three-dimensional evaluation of peri-odontal remodeling during orthodontic treatment. Se-min Orthod 8:23-28, 2002
1. Sebaoun J-D, Ferguson DJ, Wilcko MT, et al: Corticoto-mie. Alvéolaire et traitements orthodontiques rapides.Orthod Fr 78:217-225, 2007
2. Machado IM, Ferguson DJ, Wilcko WM, et al: Reabsor-cion radicular. Despues del tratamiento ortodoncicocon o sin corticotomia alveolar. Rev Ven Ort 19:647-653,2002
3. Murphy NC: In vivo tissue engineering for orthodontists:a modest first step, in Davidovitch Z, Mah J, SuthanarakS (eds): Biological Mechanisms of Tooth Eruption, Re-sorption and Movement. Boston, Harvard Society for theAdvancement of Orthodontics, 2006:385-410
4. Moss ML: The functional matrix hypothesis revisited.4. The epigenetic antithesis and the resolving synthe-sis. Am J Orthod Dentofacial Orthop 112:410-414,1997
5. Singh GD: On growth and treatment: the spatial matrixhypothesis, in McNamara JA Jr (ed): Growth and Treat-ment: A Meeting of the Minds. Craniofacial GrowthSeries No. 41. Ann Arbor, University of Michigan Press,
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