Progressive-Idiopathic Condylar Resorption- An Orthodontic Perspective

Progressive/Idiopathic Condylar Resorption:An Orthodontic PerspectiveChester S. Handelman, DMD, and Charles S. Greene, DDS

This article opens with a definition of progressive/idiopathic condylar re-

sorption (PCR/ICR), which is a severe form of degenerative joint disease that

selectively affects the temporomandibular joint. The demographics of this

relatively rare condition have been reported, and it is clear that female

adolescents are the main affected group. Some cases occur spontaneously,

whereas others appear during orthodontic therapy or as sequelae to orthog-

nathic surgical procedures. Whereas the condylar cartilage and bone are the

main tissues involved, the role of the articular disk remains controversial.

The authors report the results of a survey of orthodontists regarding their

experience with PCR/ICR, and based on those results, an estimate of 1 case

per 5000 orthodontic patients was reached. The next section of this article

discusses practical aspects of recognizing and managing PCR/ICR in the

orthodontic practice. It is essential for orthodontists to recognize the onset

of this condition in their own patients as early as possible, and if cases are

referred from outside the practice, they may not present with an established

diagnosis. Imaging techniques such as tomograms and cone beam com-

puted tomography scans have been shown to have value in the initial

diagnostic process as well as in monitoring the condition over time. Man-

agement of PCR/ICR patients with oral appliances and surgical procedures

requires continuous collaboration between the orthodontist and other pro-

fessional colleagues. The final section includes 2 case reports of patients

treated by a combination of orthodontic treatment and orthognathic sur-

gery. These are followed by an in-depth discussion of the medico-legal

aspects of managing PCR/ICR in the orthodontic practice. (Semin Orthod

2013;19:55-70.) © 2013 Elsevier Inc. All rights reserved.

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Introduction

P rogressive condylar resorption (PCR), whichis alternatively called idiopathic condylar re-

sorption (ICR), is an uncommon degenerative dis-ease of the temporomandibular joint (TMJ) of anaggressive nature that is seen mostly in femaleadolescents and young women. Pathognomonic

Department of Orthodontics, College of Dentistry, University ofIllinois at Chicago, Chicago, IL.

Address correspondence to Chester S. Handelman, DMD, De-partment of Orthodontics, College of Dentistry, University of Illinoisat Chicago, 801 S. Paulina St, Room 131A, Chicago, IL 60612-7211. E-mail: [email protected]

© 2013 Elsevier Inc. All rights reserved.1073-8746/13/1902-0$30.00/0
http://dx.doi.org/10.1053/j.sodo.2012.11.004
Seminars in Orthodontics, Vol 19,

features of this condition include a loss of condylarmass, thereby decreasing the height of the ramusand length of the mandible, and opening rotationof the mandible resulting in a Class II open bite.The purpose of this article is to provide the ortho-dontist with practical knowledge about the diagno-sis of this disease and an approach to its manage-ment and treatment. We have updated andexpanded a previous “Ask Us” column that ap-peared in the American Journal of Orthodonticsand Dentofacial Orthopedics.1 In addition, we

ave included long-term records of 2 patients tollustrate the problems the orthodontist mightace. We also report findings from an unpublishedurvey of a group of orthodontists to determineheir experience with this troubling disease.2 Fi-

nally, we will discuss the orthodontists’ responsibil-

55No 2 (June), 2013: pp 55-70

mailto:[email protected]

http://dx.doi.org/10.1053/j.sodo.2012.11.004

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56 Handelman and Greene

ity in managing the care of the PCR/ICR patient,and the methods to avoid legal liability sometimesassociated with these patients.

The orthodontist is likely to have contact withpatients afflicted with PCR/ICR in the following 2contexts. The first are patients who spontaneouslymanifest PCR/ICR independent of surgical inter-vention. The most troubling are those who de-velop PCR/ICR during orthodontic treatment orin retention. These patients are almost alwaysyoung female adolescents, whereas others are af-flicted in their late teens or early 20s. They usuallyreport that their occlusion was acceptable in thepast, but has deteriorated. The second group ispatients who have undergone orthognathic sur-gery for correction of any 1 or more of the follow-ing conditions: anterior open bite, mandibular ret-rognathia, or long anterior face height. Aftersurgery, the intermaxillary correction appears tobe successful, but by the third to sixth month, thecorrection starts to fail to a variable extent.3,4

Are these 2 scenarios as described differententities? Or are they the same, only manifestedat somewhat different ages and under differentcircumstances? In both cases, these patientsshare similarities in sex, age, malocclusion, skel-etal pattern, and condylar pathology. With theexception of subjects with known medical ortraumatic causality (see the Sarver5 article in thisissue), these PCR patients are described as “id-iopathic” or ICR.

Sex and Age

PCR/ICR is a disease of young females in theirteens or early 20s. Many diseases have a higherincidence in either males or females; for ex-ample, a greater number of females are re-ported to suffer from temporomandibular dis-orders.6 It is unusual for disease expression to

e almost completely in 1 sex when the sexualrgans are not directly involved. Gunson et al7

have made a case for low serum 17 �-estradiols a major factor in PCR. They state that oralontraceptive pill use and abnormal menstrualycles are often seen in women with severeondylar resorption. Milam8 states that estro-

gen receptors are present in the female TMJ,and because estrogen can have a negative in-fluence on joint tissues, there may be a predis-position to degenerative joint disease in cer-
tain females, including osteoarthritis.
But why should there be a preponderance ofadolescent and young women? The premen-strual female may have insufficient circulatingestrogen to initiate condylar pathology. The ageof expression of PCR/ICR is in adolescent andyoung females up to the third decade of life.9

There appears to be an unexplained “burnout”of the resorption process in afflicted individualssometime in the mid-20s, although resorptioncan extend into the early 30s. Because of theinfrequency of PCR/ICR, data collection hasbeen difficult, and we must rely on clinical ob-servation.

Mechanical Loads

The healthy TMJ by normal remodeling10 canwithstand and adapt to excessive mechanicalloads that are frequently experienced, includingparafunctional habits like nocturnal grinding,orthodontic procedures like elastics, and ortho-pedic appliances such as Herbst or chin cup. Inaddition, third molar extractions and facialtrauma as well as orthognathic surgical proce-dures can produce heavy loading on the TMJs.10

However, certain female adolescents and youngadults are susceptible to degenerative joint dis-ease that progresses to condylar resorption whentheir TMJs are exposed to excessive mechanicalloads. Essentially, the intrinsic adaptive capacityof the joints to withstand mechanical loads isexceeded by the functional (or parafunctional)demands.9-11

Even healthy joints cannot withstand extrememechanical loads that exceed their adaptive capac-ity. One example is severe trauma, and another issurgical mandibular advancement over 5 mm. Forexample, Scheerlink et al12 have shown that surgi-al mandibular advancement of �5 mm resultedn only 2% of patients developing significant con-ylar resorption, whereas 10% of cases with-10-mm advancement had resorption, and inases with �10-mm advancement, 67% had re-orption. Apparently, the forces produced by thetretched musculature and soft tissues exceededhe adaptive capacity of the joints in those cases.

The Orthognathic Surgery Patient

Orthognathic surgery for the correction of the
Class II open bite patient usually involves maxillary

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57Condylar Resorption—An Orthodontic Perspective

impaction through a Le Fort I osteotomy to inducemandibular closing rotation, combined with man-dibular advancement through bilateral sagittalsplit osteotomies (BSSO). Both surgeries will causea sudden repositioning of the condyle in thefossa, which increases the mechanical load in thejoint.3,10,13 In most patients, the joint will remodeland adapt to this change, but in some patients, theremodeling capacity of their TMJs is exceeded bythe functional demands of these sudden changes,and their condyles will resorb. Arnett et al13 have

emonstrated that the use of bicortical screws tooin the mesial and distal segments as part of fixa-ion during BSSO can rotate the condylar seg-

ents either laterally or mesially relative to thelenoid fossa; this torquing of the condyle couldnitiate condylar resorption. Therefore, they sug-est using titanium bone plates adapted to theuter cortical surfaces of the 2 segments to mini-ize this problem. They also point out that over-

eating the condyle in the fossa during BSSO canause compression and result in dysfunctional re-odeling of the joint.13

Surgical procedures to correct the Class IIopen bite and associated mandibular retrog-nathia were in place by the mid-1970s. In the1980s-1990s, there was an increasing number ofpatients undergoing orthognathic surgery. Anumber of Dutch surgeons observed that somepatients with satisfactory initial response to surgerysubsequently would lose variable amounts of theircorrection, and they realized that this was mostlydue to condylar resorption. Two factors contrib-uted to their diagnosis: (1) they had extensivedocumentation on a large number of surgical pa-tients before and after surgery as well as long-termfollow-up, and (2) they understood that the con-dyle was sensitive to pathologic resorption becauseof the pioneering research by their mentor Dr. G.Boering, who had described “arthrosis deformans”in the 1960s.14 Table 1 is a list of 5 articles selected

ecause of population size for subjects who had

Table 1. Incidence of Condylar Resorption AfterOrthognathic Surgery for all Surgery Patients

Incidence %

Kerstens et al15 12 of 206 5.8Moore et al16 5 of 421 1.2Bouwman et al17 32 of 1025 3.1Merks et al18 8 of 329 2.4

19
Hwang et al 17 of 452 3.8
rthognathic surgery.15-19 In these patient groups,PCR/ICR had an incidence of between 1.2% and5.8%. When the surgeons probed further, theyfound the relapse was concentrated in the Class IIhigh-angle group. For this select group, the PCR/ICR-induced relapse was between 19% and 31%(Table 2).15,17,20-22 This condylar resorption wasabeled “idiopathic,” as it was difficult to determinehich patients would have a successful or an un-

uccessful outcome.Reoperation on the PCR/ICR patients whose

rst orthognathic surgery was unsuccessful hadlose to a 50% failure rate.18,23-25 As the sur-eons became more aware of the possibility ofostsurgical resorption problems, they morearefully evaluated their patients for preexistingigns of PCR/ICR before doing orthognathicurgery. Again the results were not favorable:rnett and Tumborello23 reported 4 of 9 sub-

jects had postoperative condylar resorption,whereas Huang et al26 reported 4 of 18 had a

ostsurgical relapse.In a study by Hoppenreijs et al,21 the incidence

or condylar resorption after surgery performednly on the maxilla for correction of Class II openite was less than after bimaxillary osteotomies9% compared with 23%). However, most severelass II open bite patients who require surgery willenefit from surgery in both jaws as well as andvancement genioplasty to maximize profile im-rovement, so their risk for PCR/ICR will bereater. Hoppenreijs et al also demonstrated thathe initial correction can relapse due to condylaresorption by the sixth month, and this resorptionan continue for up to 3 years.21

The Pathology of the CondyleUndergoing Resorption

The TMJ condyle is covered with a layer of fibro-cartilage.8,9 During PCR/ICR, this tissue breaks

Table 2. Incidence of Condylar Resorption AfterOrthognathic Surgery in Patients Selected for ClassII High Angle

Incidence %

Kerstens et al15 12 of 49 24Bouwman et al17 32 of 158 20DeClercq et al20 9 of 29 31Hoppenreijs21 27 of 117 23Miguel et al22 5 of 26 19

down, and then the outer cortex of the osseous

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condyle starts to resorb. This is seen on radio-graphic images as resorption lacunae, with thedisappearance of the dense outer cortical layer.Other changes include narrowing as well asshortening of the condylar length, and sclerosisof the cortical bone.8 There is demineralizationof the bone below the cortex of the condyle.This may result in the collapse of articular sur-face bone, which is clinically manifested by arapid opening of the bite and opening rotationof the mandible, as reported by some patients.9

Although the disease is described as condylarresorption, there may also be resorptive changesoccurring in the articular eminence and fossa,which tend to flatten.3,9 PCR/ICR can affectither 1 or both condyles; if unilateral, the results significant facial asymmetry. However, in mostases, both condyles are involved, although 1oint may demonstrate more advanced pathol-gy than the other. This more common bilateralattern may indicate a genetic predisposition asell as the humoral nature of the etiology. Theetails of the microcellular and biochemicalvents are presented elsewhere in this sympo-ium27 and in comprehensive review articles.8-

1,28

The Role of the TMJ Disk inDevelopment of PCR/ICR

The TMJ disk acts as a shock absorber duringload-bearing movements, while also providinglubricated surfaces over which translation androtation movements occur.11,29 The role of thedisk in the etiology of PCR/ICR is controversial.The functional surfaces of both the condyle andthe articular eminence can show degenerativechanges when the disk is perforated or displacedwithout reduction.30,31 Link and Nickerson32

studied patients referred for orthognathic sur-gery and reported that all their open bite casesand 88% of their Class II malocclusions hadbilateral disk displacement. Wolford and Carde-nas33 recommend joint surgery to attach the

isplaced disk to the head of the condyle beforer during orthognathic surgery for PCR/ICR torevent recurrence of disk displacement. Otherurgeons do not agree that disk surgery is nec-ssary, so they do not enter the joint when per-orming orthognathic surgery for these types ofatients.13,25-27 It should be remembered that
isk displacement occurs in a significant num-
er of asymptomatic individuals,34 whereasCR/ICR is a relatively rare occurrence.2 Also,atients with degenerative joint disease of theMJ do not necessary have abnormally posi-

ioned disks.34

Survey of Orthodontists AboutPCR/ICR

One of the authors (C.H.) mailed a question-naire regarding PCR/ICR experience to a groupof orthodontists who were members of the Mid-west component of the Edward H. Angle Societyand/or faculty of the orthodontic department atthe University of Illinois, Chicago.2 From 69mailings, there were 57 responses, and thesepractitioners reported seeing only 56 cases ofPCR/ICR during their years in practice. An in-cidence of PCR/ICR of approximately 1 per5000 patients was derived by estimating the num-ber of new patients examined over the years ineach practice. Undoubtedly this number is onthe low side due to failure to recognize thedisease, but it does demonstrate the infrequencyof PCR/ICR that is seen in an orthodontic prac-tice. Surgery centers that perform a large num-ber of orthognathic procedures have reportedan incidence of 2%-5% (Table 1), which is stillinfrequent but more common than reported bythe orthodontists.

Of the 56 cases of PCR/ICR recorded in thissurvey, 35 were spontaneous with no history ofsurgery, whereas 21 developed the problem aftersurgery. The following data were derived from40 of the questionnaires where there was ade-quate reporting:

● The PCR/ICR group was composed of 38 fe-males and 2 males who were brothers. Therewere 37 whites, 3 Asians, and no blacks in thegroup.

● Of the 40 cases, 33 were reported to be bilat-eral and 7 were unilateral.

● The incidence of TMJ or facial pain was 12 of39 cases, with 1 case not reported.

● The malocclusions before PCR/ICR were di-agnosed as 14 Class I, 1 Class I open bite, 12Class II, 12 Class II open bite, and 1 unclassi-fied.

● Severity of the PCR/ICR, as rated by the re-spondents, was 1 case mild, whereas 39 were
described as severe or extreme.

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From their responses, it is clear that these werepatients who the orthodontist remembered well.This survey should be repeated with a greaternumber of orthodontic offices participating.However, even these limited findings confirmthe anecdotal reports in the literature that PCR/ICR is a disease affecting young females of whiteor Asian race, less than half presenting with TMJpain, and with variable occlusions before devel-oping this problem; when PCR/ICR does occur,it presents a severe treatment problem.

Diagnosis of the PCR/ICR Patient

History

A careful history can reveal the probable diag-nosis of PCR/ICR. A report of a sudden changein occlusion, especially when growth is no longera factor, is nearly pathognomonic of PCR/ICR.Unfortunately, this change may occur duringorthodontic treatment, when it easily can bemisinterpreted as being due to unfavorablegrowth, tongue thrust, or poor cooperation, or itmight initially be regarded as a response to treat-ment mechanics.

A history of autoimmune and collagen dis-eases should be documented.5 Referral to a phy-ician for blood surveys of rheumatoid factorshould be done, although this is usually nega-ive. A history of TMJ discomfort and disk dis-lacement is important, as a high percentage ofCR patients will report pain or other temporo-andibular disorder symptoms2 and have dis-

placed disks.32 When pain is reported, it mayindicate that the disease is active.

A family history of rheumatoid, TMJ distress,and malocclusion should be recorded eventhough there has been no report of familial inci-dence of PCR/ICR. A history of facial trauma—especially when the TMJ is involved—is importantas a possible cause of condylar resorption.5 Facialtrauma is common during adolescence and theearly 20s; fortunately, only rarely does a traumacase evolve into PCR/ICR.

Orthodontic treatment and third molar ex-tractions have been considered possible causesof PCR/ICR.10,27 We must remember that this is

rare disease, and a large percentage of theoung have had either or both orthodontic treat-ent and third molar extractions. It is problem-

tic to assign etiology of a rare disease to a

ommon experience—and this issue oftenomes into play when families seek legal redressfter their child develops PCR/ICR during orfter orthodontic treatment.

A history of irregular menstrual cycles, amen-rrhea, and use of oral contraceptive pills haseen reported by Gunson and Arnett et al7 in

orthognathic surgery patients who developedPCR/ICR. They suggest that mid-cycle serumlevels of 17B-estradiol should be measured, be-cause low levels were associated with postsurgicaldevelopment of severe resorptive problems.

Orthopantogram and CephalometricRadiographs

The orthopantogram (OPG) can be used forgross examination of the condyle. The condylewill appear to have lost mass relative to the restof the mandible, and it can appear thin or short-ened with flattening of the superior and/or an-terior curvature.25 In many cases, there will be adistal inclination of the condylar neck.19,21,35

The cephalometric radiograph will showmandibular divergence relative to the cranialbase and maxilla, shortened posterior facialheight, and increased anterior facial height withan increase in the overjet and negative overbite.Sagittal measures for skeletal Class II will beincreased. Serial cephalometric radiographs areprofoundly diagnostic of active ICR. There aremany choices for superimposition of the films,but the method used in the case reports in thisarticle superimposes on the basion–nasion planeat basion. The posterior shadow of the condyleon this plane is defined as articulare. Its locationwill reposition mesially when ICR is active. Themandible on the succeeding cephalometric ra-diograph will show an opening rotation, a short-ened posterior height (articulare to gonion),and shortened length (Figs 1 and 2). One limi-tation of cephalometric films is that it is fre-quently difficult to visualize the shadow of thehead of the condyle in advanced PCR/ICR sub-jects because of the resorption.

Cone Beam Computed Tomography

Although cone beam computed tomography(CBCT) has increased radiation and cost relative toOPG and cephalometric films, it is justified becauseof the clarity of the views and the avoidance of super-
imposition of adjacent structures. This enhances the


Figure 1. Patient 1 (All cephalometric superimpositions are on the basion-nasion line at basion.) (A) Cepha-lometric superimposition from preorthodontic treatment at 10 years 3 months (solid line) to postorthodontictreatment at 13 years (dashed line). The maxilla grew normally, whereas the mandible grew vertically but notanteriorly. The mandible rotated down and back, and articulare moved mesially. (B) Cephalometric superim-position of postorthodontic treatment from age 13 years (solid line) to 14 years (dashed line). The maxilla grewnormally, whereas the mandible rotated downward and backward, causing an open bite with an increasedoverjet. Articulare moved forward. (C) Cephalometric superimposition from age 14 years (solid line) to 15 years10 months (dashed line). The maxilla has stabilized as growth has ceased. However, the mandible continued itsdownward and backward rotation and regression, with shortening of the ramus. (D) Cephalometric superim-position from 15 years 10 months (solid line) to 30 years 6 months (dashed line). The condylar resorption hascontinued with shortening of the ramus and mesial movement of articularie. (E) Cephalometric superimpositionfrom 18 years 6 months (solid line) to 30 years 10 months (dashed line). The condyle continued to resorb witha downward and backward rotation of the mandible. (F) Tomograms at age 30 years 10 months showing the rightand left condylar processes to be small; the superior surfaces are flattened with signs of sclerosis and erosions.The ascending rami are short. (G) Cephalometric radiograph superimposition of presurgery at 34 years 8months (solid line) and after surgery at 35 years 3 months (dashed line), with dramatic improvement in theprofile seen in the dashed profile line. (H) On the left: profile portrait before orthognathic surgery showingmandibular retrognathia and lip incompetence. On the right: 9 months after surgery showing dramatic profileimprovement and lip competence. (I) Frontal view of dentition: left, pretreatment; center, 9 months aftersurgery; right, 15 months after surgery. The open bite correction achieved after surgery has moderately relapseddue to postsurgical condylar resorption. (J) Cephalometric superimposition from 3 months after surgery (solidline) at age 35 years 3 months to 1 year 8 months after surgery at 36 years 11 months (dashed line). The anteriorprojection of the mandible has regressed about 2 mm. The height of the ramus (articulare–gonion) has
shortened 6.5 mm due to postsurgical condylar resorption.


Figure 1. Continued

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clinician’s ability to diagnose detailed pathologic fea-tures of ICR/PCR such as disappearance of thedense outer cortical layer; erosions of this layer; scle-rosis, flattening, and subcortical cyst formation (seeHoppenreijs et al35 and Hatcher37 for a detailed

escription of the use of CBCT scans in this issue ofeminars). Before CBCT, tomograms of the jointere useful but they were not 3-dimensional, gener-lly giving sagittal cuts in 1 or more planes in space.oth tomograms and CBCT are taken in an opennd a closed position. Both radiographs are useful toollow the progress of PCR/ICR and to determinehen the disease is in remission. Radiologists look for

he healing of the outer cortical layer.36,37 A secondCBCT scan taken 1 year after the first should dem-onstrate a healed and stable joint before consideringsurgery. Also, superimposition of cephalometric ra-diographs should demonstrate no change duringthis period. Unfortunately, a healed joint does notnecessarily mean the disease has “burned out,” and ithas been found that orthognathic surgery can reac-tivate the resorption processes.3,4,21,25,26

The appearance of an osteophyte on the ante-rior aspect of the condyle is associated with PCR/ICR and other degenerative joint diseases, but thischange is thought to represent the healing of thecondyle, as it attempts to increase its bearing sur-

Figure 1

face to distribute the loads on the joint.37 P

Radioisotope Diagnosis

The value of performing a radioisotope study as partof the diagnosis of PCR/ICR is disputed. Some ex-perts feel this type of scan (usually done with techni-cium99) is difficult to interpret because various typesof TMJ conditions will show a high level of uptake,35

but others feel it has some diagnostic value.26

Magnetic Resonance Imaging

Magnetic resonance imaging is useful in exami-nation of the soft tissues of the TMJ, includingthe cartilaginous integrity of the condylar headsurface, disk derangement, inflammation of theTMJ, and marrow edema.37,38 However, it does

ot provide images of the bony cortices of theondyle or eminence that are clearly defined, asn a tomogram or a CBCT.

Occlusal Splints

Occlusal splints are suggested in PCR/ICR caseswhen there is pain and dysfunction in the jointand before surgery to stabilize the joint.13,27 An

ften overlooked use is its potential diagnosticpplication for determining cessation of the re-orptive process. Patients suspected of having

ntinued

CR/ICR should be fitted with a maxillary oc-


Figure 2. Patient 2 (A) Preorthodontic treatment cephalometric radiograph at 11 years 8 months showsmaxillary dental protrusion and proclination with large overjet, lip incompetence, and mandibular retrognathia.(B) Superimposition of cephalometric radiographs taken 3 months after the first surgery at age 17 years 2months (solid line) and 2 years 8 months after surgery (dashed line). After surgery, the mandible rotateddownward and backward and lost length, and the ramus shortened; these are changes associated with idiopathiccondylar resorption (ICR). (C) Orthopantogram (OPG) taken 1 year after the first orthognathic surgery showsflattening of the anterior superior aspect of the condyle. (D) Tomograms taken before the second surgery showthe left condyle shorter than the right. The superior surface of the both condyles shows signs of flattening andsclerosis, indicating a history of ICR, but there was no evidence of active ICR at this time. (E) Superimposedcephalometric radiographs taken before the second surgery at 25 years 8 months (solid line) and 1 month afterorthognathic surgery (dashed line) showing the greatly improved profile. Note dashed profile line. F. Superimposi-tion of cephalometric radiographs taken 1 month after orthognathic surgery (solid line) and 2 years 7 months aftersurgery (dashed line). The correction is stable. Lip competence is achieved as the facial swelling receded. (G) On theleft are frontal photographs of the teeth before the second surgery at age 25 years showing the anterior open bite. Onthe right is a similar photo taken 2 years 7 months after surgery at age 28 years 3 months showing stability of the openbite correction. (H) On the left is a profile taken before the second surgery at age 25 years 1 month. On the right is
the profile taken 2 years,7 months after surgery showing facial improvement and lip competence.

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clusal splint with registered contact of the man-dibular teeth. If the lower incisors no longerregister contact at a later time, this indicatesfurther joint degeneration and active disease.1

An occlusal splint should routinely be placedafter orthognathic surgery for PCR/ICR patientsat the time of retention for TMJ comfort, reduc-tion of the forces on the joint, and to evaluate

Figure 2

stability of the correction.

Timing and Surgical Options forCorrection of PCR/ICR

The role of the orthodontist before orthog-nathic surgery is to prepare upper and lowerteeth to an ideal arch form that will maximizeocclusal contact in a normal Class I occlusionafter surgery. This is true no matter which sur-

ntinued

gical approach is taken. A limited number of

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PCR/ICR cases can be successfully treated afterremission of the disease by orthodontic meanswithout performing surgery. These patients mayhave acceptable profiles, but this is not the situ-ation for the majority of such cases. The tremen-dous loss of condylar mass and the resultingfacial deformity usually require surgical recon-struction.

The timeline of the disease is that it firstappears in young adolescents, although Dib-bets39 has shown deformed condyles and growthdisturbances in a younger group (see the Dib-bets et al40 article in this issue of Seminars). Theperiod from the teen years to the early 20s ap-pears to be the most active time for PCR/ICR.Hopefully, the disease goes into remission, andperhaps a permanent “burnout” of the diseaseprocesses will occur by the mid 20s, although

Figure 2

some patients continue to be active into their m

30s (case 1—Fig. 1). Teenagers therefore shouldbe advised to postpone surgery to a later date,but young women with severe facial deformityoften would like correction to be done as soon aspossible.

If the disease is still active, replacement of thejoint with an autologous costochondral graft26

or total alloplastic TMJ prosthesis41 are optionshat guarantee postoperative stability (see the

ercuri42 article in this issue of Seminars). Theynthetic joint fitted by computer modeling isomposed of custom-made mandibular andossa components; it is made of titanium coveredith ultra-high-molecular-weight polyethylenen the articulating surfaces. It has the advantagef not requiring surgery for the rib transplant,nd the joint can be mobilized soon after sur-ery. It has the disadvantage of needing replace-

ntinued

ent over time—perhaps a number of times in

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the life of the patient. Therefore, patients whohad orthognathic surgery as teenagers that acti-vated PCR/ICR and led to a failed dentofacialresult have 2 choices: one is to wait for a numberof years, until a second orthognathic surgery ismore likely to be successful (case 2—Fig. 2), andthe other choice is to elect either autologous oralloplastic TMJ replacement as part of the sec-ond orthognathic surgery procedure.

Another option offered in a few case reportsis to advance the mandible slowly by distractionosteogenesis, thereby allowing the soft tissue andmusculature to adapt to large mandibular ad-vancements. Schendel et al43 reported a case of15.6-mm vertical and 13.4-mm horizontal ad-vancement using a curved distractor.

Gunson and Arnett28 have taken a more bio-edical and drug management approach in pa-

ients who might be prone to postsurgical PCR/CR. They prescribe an occlusal splint to reducehe mechanical loads on the joint to be worn for aumber of months before as well as after surgery.lso, before and after surgery, they place the pa-

ient on a comprehensive series of drugs to relaxhe musculature, decrease inflammation, and re-uce the patient’s inherent bone resorption capac-

ty.10,27,28 Based on their case results to date, theyfeel they can reduce the incidence of condylarresorption even in patients who are high risk forpostsurgical PCR/ICR.27,28

It is a judgment call to decide which ortho-gnathic surgical approach should be taken foreach patient. Arnett’s and Gunson’s approachis appropriate for most cases of PCR/ICR re-quiring orthognathic surgical reconstruction.For cases requiring extreme mandibular ad-vancements, distraction osteogenesis should beconsidered.43 Total joint replacement with anlloplastic TMJ should be considered only if thereceding options fail, or in patients withhronic pain or joints with compromised func-ion.41,42 However, the pain may not be resolved

even if the surgery is successful, due to a combi-nation of peripheral and central sensitization ofthe nervous system.44

Case Reports

Case 1

A female aged 10 years 3 months was treated for
a routine Class I deep bite and finished treat-
ment at 13 years and 4 months with an excellentresult. The orthodontist noted that after com-pletion of treatment, her bite opened in reten-tion and the mandible receded. He carefullyfollowed her with serial records, including ceph-alometric radiographs and study models to age18 years 6 months, when she left for college.During the 3 years of orthodontic treatment, themaxilla grew forward, as expected, but the man-dible grew vertically (Fig.1A). There was no sag-ittal advancement of the mandible, as wouldnormally occur during this period of activegrowth. Undoubtedly, condylar resorptionmixed with growth was occurring in this patient,a phenomenon described by Dibbets et al.39,40

The superimposition of the serial cephalometricradiographs on the nasion-basion line at basionshows that articulare came forward, a sign thatthe anterior aspect of the condyle was resorbing.Growth continued from the 13th through the14th year as the maxilla advanced normally (Fig.1B). The mandible, however, showed rapid pro-gression of PCR/ICR as articulare moved for-ward, and the mandible displayed extremeopening rotation with an increase in the openbite. From the 14th to the 15th year, the maxillaceased growing, but the mandible continued itsdownward and backward rotation (Fig. 1C). Ar-ticulare advanced slightly, but the mandible con-tinued to rotate and recede, probably due toresorption of the superior surface of the con-dyle. From age 15 years 10 months to age 18years 6 months, resorption was still occurring(Fig. 1D).

When the patient presented to the author’soffice (C.H.) at age 30 years, which was 12 yearsafter her last recall visit and 16 years since comple-tion of treatment, we requested her previous re-cords. Superimposition of her 18-year 6-monthcephalometric radiographs with one taken at age30 showed continuing of the backward rotation ofthe mandible (Fig. 1E). It also showed furtherincreases in the open bite, the anterior facialheight, and the mandibular retrognathia; it is as-sumed that most of these negative changes oc-curred by her early 20s. She was followed for 3 yearsin our office, and the cephalometric radiographsdemonstrated stability. The tomograms showed ex-tremely reduced condylar mass (Fig. 1F).

Despite the fact that the condyles were small,they were functional with normal opening and
acceptable protrusive and lateral movements.


The patient was pain free, both as an adolescentand as an adult. This persuaded the surgeon notto enter the joint or replace the joint with acostochondral graft (the total alloplastic TMJreplacement systems in use today were not avail-able at that time). Orthognathic surgery per-formed at age 34 consisted of maxillary impac-tion, mandibular advancement, and agenioplasty (Fig. 1G). The profile improvementwas dramatic (Fig. 1H), and the anterior occlu-sion was normalized (Fig. 1I). By the sixthmonth after retention, the bite opened in theincisor region (Fig. 1I). Re-treatment was of-fered at no cost and refused, as the patient wasthrilled with the improvements achieved. Super-imposition of radiographs taken at retentionand 1 year later demonstrates loss of posteriorheight of the mandible of 5 mm, but mandibularlength was decreased by only 2 mm (Fig. 1J).During a 3-year recall period, there was no fur-ther change in the occlusion, and the position ofthe mandible was stable on cephalometric radio-graphs.

This patient started with a malocclusion atage 10 years that was a routine treatment situa-tion. Her condyles resorbed at a variable rateduring a period of 20 years, which is unusual inlength and severity for PCR/ICR. Based on all ofthese historical data, one would have to con-clude that the inherent lack of adaptive capacityin her TMJs contributed to the significant short-ening of the height of the ramus and the mod-erate mandibular recession seen after surgery.

Case 2

A 24-year-old female of Indian Asian descent wasreferred to our office (C.H.) by her oral surgeonfor orthodontic management in Chicago, whereshe was a student. She later returned to Palo Altofor orthognathic surgery. Judging from the pre-treatment cephalometric radiograph (Fig. 2A)at age 11 years 8 months, her original occlusionwas Class II with a large overjet, maxillary dentalprotrusion, associated lip incompetence, and se-vere mandibular retrognathia. She was treatedon a nonextraction basis for 3 years with a biona-tor appliance, followed by fixed orthodontic ap-pliances. At the end of treatment, her profile wasnot acceptable to the patient and her family.The dentition was never fully corrected, and it
relapsed into a Class II open bite malocclusion.
She was then referred by her orthodontist fororthognathic surgical correction at age 16. Hos-pital records describe surgery that involved a LeFort I maxillary impaction and a BSSO in whichthe segments were stabilized by bicortical screws;a genioplasty also was performed (Fig. 2B). Thefamily and the patient report seeing 100% re-lapse by approximately 6 months after surgery,and this is confirmed by superimposition of trac-ings of cephalometric radiographs taken beforeand afer surgery (Fig. 2B). An OPG taken 1 yearafter surgery (Fig. 2C) showed deformed con-dyles that are short with reduced anterior curva-ture and with distal inclination, which are clas-sical signs of postsurgical PCR/ICR.19,26

Tomograms taken on her transfer to our of-fice demonstrated pathologic changes that indi-cated a history of PCR/ICR (Fig. 2D). However,the radiologist indicated there was no evidenceof currently active degenerative joint disease orPCR/ICR. Also, the cephalometric radiographstaken at age 25 showed no further resorptioncompared with one taken at age 19 years and 7months. Therefore, the decision was made tore-treat this patient surgically.

The surgical procedures at age 25 years 8months consisted of a Le Fort I maxillary osteot-omy rotating the anterior maxilla downward andbackward, and a BSSO with advancement as wellas a closing rotation of the mandible (Fig. 2E).The segments of the BSSO were stabilized withmonocortical screws and bone plates. There wasalso an advancement genioplasty. The cephalo-metric radiograph taken 8 months after surgerydemonstrates short-term stability of the correc-tion (Fig. 2F), and the patient subsequentlymoved to another city. We were able to have herreturn to our office 2 years after surgery forfollow-up records. Superimposition of her ceph-alometric radiographs revealed long-term stabil-ity of the correction (Fig. 2F). As the facial swell-ing receded, she was able to achieve lipcompetence, which improved her profile. Thefinal result demonstrates an improved facial ap-pearance and corrected occlusion (Fig. 2G, 2H).

In retrospect, we can presume that the 3 yearsof functional and fixed appliances thereby werenot successful because ICR may have been activeand would have masked any remaining growthof the mandible. This case illustrates that anindividual with complete postsurgical relapse
due to PCR/ICR at age 16 can have successful

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and stable surgery at age 25. The use of mono-cortical screws and bone plates in this case aftera failed surgery with bicortical screws may havemade a difference, but the most likely reason forsuccess was that the patient had entered theburnout phase of the condition.

Management of the PCR/ICR Patientand Medico-Legal Implications

We are aware of a few cases of patients whodeveloped PCR/ICR during orthodontic treat-ment, and subsequently the family brought legalaction against the orthodontist. These patientsdeveloped severe malocclusions while they werewearing active orthodontic appliances, and inaddition, they had TMJ pain and would requirefuture orthognathic (and possibly TMJ) surgery.The allegations in those lawsuits were failure todiagnose, failure to advise the family of the risksof orthodontic treatment in the informed con-sent procedures, and failure to discontinuetreatment when a diagnosis of PCR/ICR couldhave been made. Obviously, these cases raisequestions about what kind of informed consentshould be provided to prospective orthodonticpatients.

Even though PCR/ICR is a serious disease, itis not medico-legally required to inform everypatient that PCR/ICR may occur before startingroutine orthodontic treatment, as its incidenceis so rare—approximately 1 case per 5000 pa-tients.2 However, once the orthodontist is suspi-ious that PCR/ICR may be present, a discussionf the risks of further treatment becomes man-atory. This is especially true if orthognathicurgery is contemplated. The incidence of PCR/CR for all surgery patients is between 1.2% and% (Table 1), and this rises to between 20% and5% for the Class II high-angle patient (Table).

If patients (especially females) either presentith or develop any of the features of PCR/ICRhile you are treating them, some specific pro-edures should be considered. The clinical fea-ures to watch for include various combinationsf divergent mandible, mandibular retrog-athia, short ramus, open bite, and TMJ distress.f these are present, the patient and familyhould be informed that PCR/ICR is a possibleiagnosis. All discussions should be summarized

n the patient’s record and dated. Suspicion of

CR/ICR requires that a history should be takenollowed by certain clinical procedures. Study

odels should either be mounted or stabilizedith a polyvinylsiloxane bite to register the openite. Obviously, cephalometric radiographs sh-uld be taken both before and during treat-ent, and superimpositions should be analyzed.he OPG may be suggestive of ICR, but a CBCT

s also indicated to get a clearer picture.35

When confronted with the possibility thatyour patient has PCR/ICR, the orthodontistshould rely on collaboration with a team of ex-perts: an oral radiologist (to submit a writtenreport on the CBCT scans), an oral surgeon withextensive experience with orthognathic surgeryand ideally with experience in dealing withPCR/ICR cases, and referral to a rheumatologistfor blood tests to rule out autoimmune andrheumatoid diseases. The record taking, theconsultations, and the discussions should edu-cate the patient and family that this is not aproblem limited to “crooked teeth,” but insteadthe patient may have a medical problem involv-ing pathologic tissue, possible pain and dysfunc-tion, and abnormal occlusal and skeletal mor-phology of a serious nature.

What should the orthodontist do when thediagnosis of ICR is made and the patient is stillin orthodontic appliances? The number-1 rulethat has emerged from both clinical and medico-legal experience is this: discontinue treatment andretain. However, continue to monitor the patientevery 6 months and take annual cephalometricradiographs and CBCT scans; all of this shouldbe done in conjunction with your professionalcolleagues who will be involved with this case.Once the condyle has healed and the occlusionis stable, discussion of orthodontic treatmentonly or possible surgical options should be con-ducted with all parties, with the patient beingpart of the decision-making group. Both em-phatic communication that “you really care” andcareful record keeping will minimize the chanceof legal liability.

Conclusions

Hopefully, the information in this article andthe other articles in this issue of Seminars inOrthodontics will enable the orthodontist to make
informed choices about diagnosis, management,


and treatment of patients who are afflicted withthis rare and incompletely understood disease.

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Documents

Progressive-Idiopathic Condylar Resorption- An Orthodontic Perspective