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Progressive idiopathic condylar
resorption: Three case reports
Sylvain Chamberland
Quebec City, Quebec, Canada
Progressive condylar resorption, also known as idiopathic condylar resorption, is an uncommon, aggressive,
degenerative disease of the temporomandibular joint (TMJ) seen mostly in adolescent girls and young women.
This condition leads to loss of condylar bone mass, decrease of mandibular ramal height, steep mandibular and
occlusal plane angles, and an anterior open bite. In 3 case reports, we review the pathogenesis of TMJ degen-
erative disease and the clinical management of TMJ arthrosis. We emphasize that TMJ arthritic disease should
be discussed in dental circles as a pathologic entity in the same way that orthodontists discuss arthritic disease in
orthopedic circles. Regarding the degenerative pathology of the TMJ, treatment goals include restored function
and pain reduction. The treatment methods used to achieve these goals can range from noninvasive therapy to
minimally invasive and invasive surgery. Most patients can be treated noninvasively, and the importance of dis-
ease prevention and conservative management in the overall treatment of TMJ disease must be acknowledged.
The decision to manage TMJ osteoarthrosis surgically must be based on evaluation of the patient's response to
noninvasive treatments, mandibular form and function, and effect of the condition on his or her quality of life. (Am
J Orthod Dentofacial Orthop 2019;156:531-44)
Progressive condylar resorption (PCR) also known
as idiopathic condylar resorption (ICR) is an un-
common, aggressive, degenerative disease of the
temporomandibular joint (TMJ) seen mostly in adoles-
cent and young women.
1,2
This disorder has a female
prevalence of 9:1. Constitutional risks factors, besides
female predilection, are hormonal imbalance
(Yestrogen, Y17b-estradiol), nutritional status
(Yvitamin D, Ydietary omega-3 fatty acids), bruxism,
and repetitive oral habits. Iatrogenic causes have been
reported to include orthodontics, orthognathic surgery,
intermaxillary fixation, and improperly designed and
used occlusal appliances, all resulting in condylar
displacement and compressive TMJ overloading.
3
PATHOLOGIC CHANGES
PCR is best describe as a localized noninflammatory
degenerative disorder of the TMJ and is characterized
by lysis and repair of the articular fibrocartilage and un-
derlying subchondral bone.
4
This condition leads to loss
of condylar bone mass, decrease of mandibular ramal
height, steep mandibular and occlusal plane angle, and
an anterior open bite. Most of the destructive process
is localized to the bone superior to a line bisecting the
condylar poles. The active phase of PCR is often associ-
ated with limited jaw opening and TMJ pain, followed by
condylar flattening. This may form a congruent articula-
tion with the opposing posterior aspect of the articular
eminence which permits redistribution of functional
loads, thereby restoring some condylar motion and
reduction in pain.
PCR occurring before the completion of growth re-
sults in a shorter condyloid process, shorter ramus,
shorter mandibular body, compensatory growth at the
gonial angle, and increased vertical dimension of the
anterior facial region. As ramus height is lost, develop-
ment of an anterior open bite is likely. There is a ten-
dency for a reduction in airway dimension secondary
to decreased mandibular growth
4
or, in the case of a pa-
tient who has completed growth, progressive
mandibular retrusion.
Reduction in airway dimensions can lead to the risk
of developing sleep apnea. Increased lower anterior
facial height may cause lip incompetence in repose
and reduced alveolar bone thickness at the facial aspect
of the incisors.
IMAGING MODALITIES
The orthopantomogram (OPG), as a panoramic
radiograph is termed internationally, is the least
Private practice, Quebec City, Quebec, Canada.
All authors have completed and submitted the ICMJE Form for Disclosure of Po-
tential Conflicts of Interest, and none were reported.
Address correspondence to: Sylvain Chamberland, 10345 Boul de l'Ormiere,
Quebec, QC, Canada G2B 3L2; e-mail, drsylchamberland@videotron.ca.
Submitted, March 2018; revised and accepted, May 2018.
0889-5406/$36.00
Ó2019 by the American Association of Orthodontists. All rights reserved.
https://doi.org/10.1016/j.ajodo.2018.05.023
531
CASE REPORT
expensive imaging modality for gross evaluation of the
condyle. Loss of bone mass or flattening of the anterior
or superior aspect of the condyle, as well as a distal
inclination of the condylar neck, is easily observable on
the OPG.
A cephalogram would display a shortened posterior
facial height, increased anterior facial height, increased
overjet, and open bite. Serial cephalograms taken during
the active stages of PCR would show a more mesial
position of the articulare point.
1
Cone-beam computed tomography (CBCT) permits
3-dimensional evaluation of the condyle and helps to di-
agnose features such as condylar degeneration, erosion,
sclerosis or flattening of the dense cortical layer, and
subcortical cyst formation (Ely cyst).
1
Magnetic resonance imaging (MRI) is the preferred
technique for investigation of the soft tissues of the
TMJ, including cartilaginous integrity of the articular
surfaces, disk derangement, and inflammation.
T1-weighted MRI is helpful in identifying disc position
and alterations in bone and soft tissue anatomy, and
T2-weighted MRI is useful for identifying inflammatory
response as well as TMJ condylar bone marrow
edema.
2,5,6
Nuclear medicine bone scanning with the use of
technecium-99 can be used to assess whether there are
any active bony changes, but the specificity is not suffi-
cient to assess the state of stability or remission of those
changes.
1,4
PATHOGENESIS OF TMJ DEGENERATIVE
DISEASES
The most common joint pathology affecting the TMJ
is osteoarthrosis. Unlike rheumatoid arthritis, TMJ os-
teoarthrosis has a noninflammatory origin. The patho-
logic process is characterized by deterioration and
abrasion of articular cartilage and local thickening and
remodeling of the underlying bone. These changes are
frequently accompanied by the superimposition of sec-
ondary inflammatory changes.
7
Three main etiologies
8
have been proposed for the pathogenesis of the disease:
(1) trauma and or aberrant loading; (2) hormonal path-
ogenesis; and (3) a genetic basis for altered joint extra-
cellular matrix.
7,9,10
These are not mutually exclusive,
because a decreased adaptive capacity of the
articulating structures, hormonal factors, and excessive
physical stress on a joint can all induce dysfunctional
remodeling.
Functional overloading can facilitate hypoxia and
mediate the destructive processes associated with
osteoarthrosis as an autocrine factor. Vascular endothe-
lial growth factor (VEGF) induction in osteoarthritic
cartilage by functional overloading is linked to
activation of the hypoxia-induced transcription factor
1, leading to hypoxia in the joint tissue. Furthermore,
VEGF regulates the production of matrix metalloprotei-
nases (MMPs) and tissue inhibitors of theses enzymes,
which are among the effectors of extracellular matrix
remodeling.
Overloading also causes collapse of joint lubrica-
tion as the result of hyaluronic acid degradation by
free radicals. The regulation of hyaluronic acid pro-
duction is controlled by various proinflammatory
cytokines. Of these cytokines, tumor necrosis factor
aand interleukin-1 and -6 play crucial roles in the
pathogenesis of osteoarthrosis regarding the accel-
eration and progression of cartilage degradation,
because they promote bone resorption through
the differentiation and activation of osteoclasts
7
(Fig 1).
CLINICAL MANAGEMENT OF TMJ
OSTEOARTHROSIS
The management goals of TMJ osteoarthrosis should
be: (1) decreasing joint pain, swelling, and muscle pain;
(2) increasing joint function; (3) preventing further joint
damage; and (4) preventing disability.
The first management option includes noninvasive
modalities such as medications (nonsteroidal antiin-
flammatory drugs [NSAIDs] and muscle relaxants), phys-
iotherapy, and occlusal appliance therapy. A second set
of options includes minimally invasive modalities such
as arthrocentesis (washing out the joint), injection of hy-
aluronic acid or a corticosteroid, and arthroscopic sur-
gery. However, a recent meta-analysis concluded that
there was little evidence to support the effectiveness of
arthrocentesis in the management of TMJ osteoarthro-
sis.
11
Therefore, arthrocentesis can no longer be recom-
mended for the management of TMJ osteoarthrosis. The
third set of options involve invasive surgical modalities
such as arthroplasty, autogenous hemiarthroplasty, dis-
cectomy, and disc repositioning by means of orthog-
nathic surgery.
2
Goncalves et al
12,13
reported that
articular disc repositioning in patients treated with
maxillomandibular advancement and disc
repositioning had better long-term outcomes with less
relapse compared with a group of patients undergoing
only maxillomandibular advancement surgery. However,
the disc must be intact and the patient in the early stages
of the disease.
End-stage PCR requires salvage procedures to restore
jaw function and improve and maintain skeletal alter-
ations.
2,7
These patients require either autogenous or
alloplastic total joint replacement.
532 Chamberland
October 2019 Vol 156 Issue 4 American Journal of Orthodontics and Dentofacial Orthopedics
CASE REPORTS
Patient 1
A woman 19 years 1 month of age presented for
consultation regarding possible orthodontic treatment
for complaints of “crooked teeth”and TMJ pain. Her
TMJ pain problems began at age 16. At 17, she had con-
servative treatment with occlusal appliance therapy,
physiotherapy, muscle relaxants, and NSAIDs. A year
later, she was diagnosed with disc displacement without
reduction, limiting jaw opening to 20 mm. An oral sur-
geon did an infiltration of a local anesthetic with
epinephrine and 40 mg triamcinolone (40 g/mL). Disc
reduction was observed after infiltration, with an inter-
incisal opening of 35 mm. TMJ and myofascial pain
continued despite this treatment.
She went to a second oral surgeon for consultation,
and a month later bilateral TMJ arthrocentesis was per-
formed. One month later, she had persistent pain in the
masseters and both joints and limited mouth opening.
A third oral surgeon then infiltrated 200 U Botox
(dilution 100 U/mL) into masseter muscle trigger points.
This was followed in 1 month by infiltration of 1 mg
Decadron into each masseter.
Clinical examination revealed a Class III subdivision
left dental relationship, moderate crowding, and the
lower midline deviated to the right (Fig 2). The cephalo-
metric analysis demonstrated a dentoalveolar bimaxillary
protrusion, Class I skeletal relationship (Wits 1 mm), hy-
perdivergent (FMA 38), short ramus, excessive anterior
face height, and retrusive chin (Fig 3,A). Her profile
was convex, and her lips were incompetent in repose
(Fig 3,B).
The OPG revealed a flattened anterosuperior surface
of the left condyle with an anterior osteophyte. The
articular eminence also appeared flattened. The right
condyle appeared normal. However, both condyles had
shortened condyloid processes (Fig 4).
The treatment plan included extraction of the 4 first
premolar teeth for maximal anterior retraction and a
functional genioplasty to help obtain lip competency
and normal anterior facial height. After 13 months of or-
thodontic treatment, her teeth were aligned and the
extraction spaces were ready to close (Fig 5,Top). Joint
pain and limited mouth opening were still issues. An MRI
revealed bilateral anterior disc displacement without
reduction.
After 18 months of orthodontic treatment, bilateral
disc repositioning, extraction of all 4 third molar teeth,
and a functional genioplasty were performed. Ortho-
dontic progress records at 19 months showed a Class I
occlusion with some remaining space to be closed (Fig
5,Bottom). A profile view showed reduction of the den-
toalveolar protrusion, and a genioplasty helped in
achieving lip competence in repose (Fig 6).
Fig 1. The concept of the process of cartilage breakdown in the TMJ. From J Dent Res 2008,87:296-
307, used by permission of the publisher, Sage Publications/Corwin.
Chamberland 533
American Journal of Orthodontics and Dentofacial Orthopedics October 2019 Vol 156 Issue 4
Two months after disc repositioning, the patient's
masseter muscle and TMJ pain increased. CBCT
demonstrated a decrease in articular disc space
bilaterally (Fig 7). Physiotherapy was recommended,
and Flexeril and NSAIDs were prescribed. Three
months after surgery, the right TMJ and right
masseter muscle pain significantly increased (7/10).
One mL dexamethasone was injected into the right
TMJ. One week later at follow-up, the TMJ pain
decreased to 1/10.
The patient was then transferred to an oral surgeon
at H^
opital de l'Enfant-J
esus in Quebec City. A right
TMJ discectomy was performed in February 2015. At
the September 2015 follow-up, the right condyle
showed significant resorption, reduced interarticular
space, and flattening of the articular eminence. The
left condyle showed progression of the flattening of
the anterosuperior surface. In February 2016, a left
TMJ discectomy was performed.
At 40 months, orthodontic treatment was completed.
A functional occlusion was achieved with minimal
Fig 2. Patient 1 was a 19-year-old woman with Class III subdivision left malocclusion and moderate
crowding. The lower midline was deviated to the right.
Fig 3. A, Lateral cephalogram shows a hyperdivergent short ramus, excessive anterior face height,
and retrusive chin. B, Facial photograph reveals a convex profile and lip incompetency in repose.
Fig 4. OPG taken before orthodontic treatment shows a
flattened anterosuperior surface of the left condyle with
an anterior osteophyte. The articular eminence also ap-
pears flattened.
534 Chamberland
October 2019 Vol 156 Issue 4 American Journal of Orthodontics and Dentofacial Orthopedics
overjet and overbite. The OPG revealed a progressive loss
of right condylar bone mass (Fig 8).
Four months after debanding, an anterior open bite
had developed and continued to progress to the point
that it was decided that total joint replacement was the
only management option (Fig 9). Bilateral alloplastic
total joint replacement was performed in July 2017
with the use of Zimmer Biomet (Jacksonville, Fla)
custom prostheses (Fig 10). Follow-up records demon-
strate that a functional occlusion was established (Fig
10), despite the lack of lateral movement of the jaw,
and her facial esthetics were improved (Fig 11).
Patient 2
Patient 2, a young woman, presented with a Class II
Division 1 malocclusion and an anterior open bite (Fig
12). She had been followed by her dentist for TMJ
pain for the past 7 years. She had undergone orthodon-
tic treatment 12 years earlier for a Class I malocclusion
with severe crowding and a mandibular midline devia-
tion to the left (Fig 13,Top). Four second premolars
were extracted to alleviate crowding and the orthodon-
tic treatment proceeded uneventfully. A Class I occlu-
sion was achieved, although a slight lower midline
deviation to the left remained (Fig 13,Bottom). The
OPG at debanding revealed a shortened left condyloid
process that might explain the midline deviation to
the left and facial asymmetry (Fig 14,A). Follow-up
1 year into retention showed a normal occlusion
without TMJ symptoms. The patient's profile was
straight, with lip competence in repose. The cephalo-
gram revealed a normodivergent mandibular plane,
and the gonial angle was at the level of C2. The airway
appeared normal (Fig 15).
During the period between debanding and her visit
7 years later, she had developed significant TMJ pain.
Her general dentist made 3 splints over the years. She
stated that 1.5 years after debanding, she experienced
a sudden left TMJ lock with pain. A TMJ MRI revealed
Fig 5. Top: Progress records at 13 months. Extractions spaces are ready to close. Bottom: Progress
records at 19 months. Class I occlusion with some space remaining.
Fig 6. Profile view at 13 months shows reduction of the
dentoalveolar protrusion and lip competence in repose.
Chamberland 535
American Journal of Orthodontics and Dentofacial Orthopedics October 2019 Vol 156 Issue 4
bilateral disc displacements. On opening, the right disc
reduced, but the left side did not. No condylar degener-
ative changes were seen. Occlusal appliance therapy was
started.
Over the ensuing years, the patient gave birth to 3
children. New occlusal appliances were made after
each birth. The OPG 4 months after the birth of the first
child revealed noticeable changes in both condyles (Fig
14,B). A concavity was seen on the superior aspect of
left condyle, and resorption was seen in the lateral
pole of the right condyle. She was referred to a rheuma-
tologist for an autoimmune work-up. The physical ex-
amination and serology were inconclusive. However,
the patient complained of eczema and reported dull
pain in her left wrist and such acute pain in her knees
that she could no longer jog.
An OPG made after the third child's birth revealed se-
vere bilateral condylar resorption. A new occlusal appli-
ance was fabricated. The patient also noted that her
open bite had increased drastically, even with the oral
appliance. Cephalometric analysis demonstrated
decreased posterior face height, short mandibular ramus,
high mandibular plane angle, anterior open bite, and
retrognathic mandible. Study models taken at that
time could be hand articulated into a Class I occlusion,
Fig 7. CBCT 2 months after disc repositioning. Note the decreased articular disc space bilaterally.
Fig 8. Intraoral view shows that a Class I occlusion was achieved. The OPG in the background shows
loss of right condylar bone.
Fig 9. Intraoral photograph 12 months into retention
shows anterior open bite.
536 Chamberland
October 2019 Vol 156 Issue 4 American Journal of Orthodontics and Dentofacial Orthopedics
demonstrating that no dental changes had occurred.
One year later, an OPG revealed complete degeneration
of the mandibular condyles bilaterally (Fig 16). The in-
traoral examination showed a Class II occlusion with a
significant anterior open bite (Fig 12). Her profile
showed a recessive mandible and chin. She complained
of sleep apnea symptoms. The cephalogram revealed
significant shortening of the ramus, a gonial angle
that had moved from C2 level to C1, and a significantly
reduced airway shadow (Fig 17).
After discussion, it was decided that the best man-
agement option for this patient would be bilateral
alloplastic total joint replacement (Zimmer Biomet
custom prostheses; Fig 18).
Fifteen days after surgery the patient had a Class I
functional occlusion (Fig 19). Her profile was signifi-
cantly improved, her chin/throat projection increased,
and her lips appeared competent in repose. The lateral
cephalogram demonstrated an increased airways profile
and a normal overjet and overbite (Fig 20). She had an
interincisal opening of 20 mm with 2 mm lateral excur-
sion. This can be considered normal at 15 days after
surgery. Physiotherapy was then prescribed.
Patient 3
A girl 10 years 10 months of age had a Class II sub-
division left malocclusion with slight crowding and
moderate curve of Spee. Class II correction was achieved
with the use of Class II elastic traction. Near the comple-
tion of orthodontic treatment, relapse in the occlusion
was noted. A fixed twin force bite corrector (TFBC)
functional appliance was used.
She returned on an emergency basis 3 weeks later
owing to acute pain in the left TMJ and decreased inter-
incisal opening (25 mm). The TFBC was immediately
removed. A left TMJ disc displacement without reduc-
tion was diagnosed clinically. After physiotherapeutic
manipulation of her mandible, normal jaw mobility
was regained and 400 mg ibuprofen every 4 hours for
4 days was prescribed, followed by 400 mg every 6 hours
for 3 days. Follow-up at 14 days showed an interincisal
opening of 45 mm without pain.
Three weeks later, the patient developed another
closed-lock with left TMJ pain. She was then referred
to a physical therapist and instructed to take the
ibuprofen as previously prescribed for another week.
Two months later, at debanding, her interincisal
Fig 10. OPG 1 month after Zimmer Biomet custom total joint replacement. Class I functional occlusion
was achieved.
Fig 11. Profile view, 1 month after total joint replacement.
Chamberland 537
American Journal of Orthodontics and Dentofacial Orthopedics October 2019 Vol 156 Issue 4
opening was 41 mm with no pain and a Class I occlu-
sion (Fig 21,A). However, the OPG revealed flat-
tening of the anterosuperior surfaces of both
condyles (Fig 22,A). This suggested incipient
condylar morphology change likely due to resorption.
Follow-uprecords3and9monthsintoretention
showed progressive bite opening (Figs 21,Band C).
The OPG 9 months into retention revealed signs of
significant TMJ PCR (Fig 22,B), and the OPG at de-
banding showed bilateral condylar flattening. This
Fig 13. Initial photos (top) show class I occlusion with moderate crowding. Final photos (bottom) show
Class I occlusion after extraction of 4 second premolars.
Fig 14. A, OPG after at debanding shows a shortened left condyloid process, similar to initial OPG. B,
OPG 4 months after the birth of her first child shows concavity on the top of the left condyle and resorp-
tion of the lateral pole of the right condyle.
Fig 12. Patient 2. Adult woman with Class II Division 1 malocclusion, anterior open bite, and a 7-year
history of TMJ pain.
538 Chamberland
October 2019 Vol 156 Issue 4 American Journal of Orthodontics and Dentofacial Orthopedics
may explain relapse toward class II that was noted
toward the end of treatment.
Calcium (500 mg) plus vitamin D (1000 UI) once per
day was prescribed for 30 days. She was referred to an
oral surgeon and a rheumatologist. Blood testing was
negative for any systemic pathology (rheumatoid factor,
anti–cyclic citrullinated peptide, C-reactive protein,
antinuclear antibody, 17b-estradiol, and vitamin D
levels were normal).
Twenty months into retention, she had an ante-
rior open bite of 3 mm, slightly more severe on the
left side (Fig 23). She reported often feeling dull
pain in the right joint. On OPG, both condyles
showed significant flattening of the anterosuperior
aspect and the condylar neck was inclined posteri-
orly. The right joint showed more flattening than
the left joint, suggesting more resorption (Fig 24).
This might explain why the bite was more open
on the left side.
Instructions were reinforced that the patient should
not chew gum and should resume daily vitamin D and
calcium. Despite the rheumatologist finding no evi-
dence, we suspected that this could be a case of oligoar-
ticular subtype of juvenile idiopathic arthritis (JIA) rather
than ICR. Further investigation is necessary to obtain a
final diagnosis.
DISCUSSION
Patients 1 and 2 had end-stage condylar resorption
resulting in end-stage diseased TMJs requiring salvage
total joint replacement. Patients 1 and 3 had the onset
of symptoms at ages 13-15 years and could be diag-
nosed with ICR. Case 2 developed symptoms in her
mid-20s when she reported sudden locking of her left
TMJ. Because she also reported mild knee and wrist
pain and eczema, a form of inflammatory arthritis was
suspected. Further, 3 pregnancies likely played a role
in dysfunctional TMJ condylar remodeling and
resorption.
9,14
Fig 15. Profile and cephalogram at the end of orthodontic treatment revealed a normodivergent
mandibular plane as well as normal airway width and lip competence in repose.
Fig 16. OPG 1 year after the birth of her third child shows
complete degeneration of mandibular condyles bilater-
ally.
Chamberland 539
American Journal of Orthodontics and Dentofacial Orthopedics October 2019 Vol 156 Issue 4
There is growing evidence that sustained inflamma-
tion induces degeneration of the TMJ
15-17
and can
lead to deterioration of the joint's mechanical
properties as well as alteration of the disc
ultrastructure which might contribute to TMJ disc
displacement.
16
This agrees with Wolford's hypothesis
2
that female
hormones can influence biomechanical change within
the TMJ, causing hyperplasia of the synovial tissues.
This would stimulate the production of cytokines that
initiate breakdown of the ligamentous structure that
normally support and stabilize the articular disc with
Fig 17. Profile view shows recessive mandible and chin. Cephalogram reveals significant shortening
of the ramus. Gonial angle moved from C2 to C1 and reduced oropharyngeal airway shadow.
Fig 18. Left total joint prosthesis (Zimmer Biomet).
540 Chamberland
October 2019 Vol 156 Issue 4 American Journal of Orthodontics and Dentofacial Orthopedics
the condyle, resulting in anterior disc displacement. Ac-
cording to this hypothesis, the cytokines penetrate
through the outer surface of the condyle and cause thin-
ning of the cortical bone leading to breakdown of the
subcortical bone. The condyle slowly collapses without
clinically apparent destruction of the fibrocartilage. In
patients where the pathologic process is in remission,
excessive joint loading (ie, parafunctional habits,
trauma, orthodontics, orthognathic surgery) can
reinitiate the resorption process.
Symptoms of TMJ synovitis include pain during jaw
movement, crepitus, and restricted mouth opening. Iso-
lated TMJ synovitis can be a presentation of the oligoar-
ticular subtype of JIA.
18
It remains unknown whether
JIA-related TMJ arthrosis and ICR are distinct condi-
tions. Isolated TMJ arthrosis may be the first or only
Fig 19. Intraoral photograph 15 days after surgery shows a Class I occlusion.
Fig 20. Profile photograph 15 days after surgery shows improved chin projection, decreased anterior
facial height, and lip competence in repose. The cephalogram demonstrates an increased airway pro-
file and a normal dental overjet and overbite.
Fig 21. Patient 3. A, Frontal view at debanding. B, Follow-up at 3 months. C, Follow-up at 9 months.
Note progressive bite opening within 9 months.
Chamberland 541
American Journal of Orthodontics and Dentofacial Orthopedics October 2019 Vol 156 Issue 4
manifestation of JIA and may not be as rare as previously
reported. Many patients are seen initially by a dentist or
an orthodontist who may not be familiar with JIA, so
they misdiagnose the patient with either ICR or some
other TMJ disorder.
19
Epidemiologic studies have confirmed the higher
prevalence of TMJ disease and pain in women than in
men. Estrogen receptors have been identified in TMJs
and may regulate the synthesis of proteins involved in
articular tissue turnover in the TMJ. Estrogens enhance
responses to relaxin, a polypeptide implicated in MMP
synthesis and activation. MMPs have been implicated
in the degradation of the cartilaginous matrices in
degenerative TMJ diseases.
10
There is evidence that
relaxin contributes to the degradative remodeling of
joint fibrocartilage and that there is an association be-
tween relaxin-induced MMPs and matrix loss, suggest-
ing a potential mechanism of action of relaxin in
contributing to TMJ diseases in a subset of women
with these disorders.
20
These findings show that relaxin,
which is found systemically in cycling and pregnant
women but not in men, causes the targeted induction
of tissue-degrading enzymes of the MMP family in the
fibrocartilaginous tissues of the TMJ, potentially predis-
posing to TMJ disease. Moreover, it has been found that
the TMJ disc and pubic symphysis show the greatest in-
duction of MMPs and matrix loss in response to relaxin
and 17b-estradiol.
14,21
This helps to explain the role of
hormones in the disease of patient 2.
Fig 22. A, OPG at debanding. Flattening of both anterosuperior superior surfaces of both condyles is
evident. B, Follow-up at 9 months after orthodontic treatment.
Fig 23. Follow-up at 20 months after treatment shows 3 mm anterior open bite.
Fig 24. OPG at 20 months' follow-up. Both condyles
show significant flattening of the anterosuperior aspect,
and the condylar neck is inclined posteriorly. The right
joint shows more flattening than the left, suggesting
more resorption.
542 Chamberland
October 2019 Vol 156 Issue 4 American Journal of Orthodontics and Dentofacial Orthopedics
WHAT TO DO?
Early diagnosis of TMJ degenerative change should
include a careful examination of the condyle and condy-
loid process on the screening OPG. Signs of degenerative
bony condylar changes or condyloid process shortening
may be present despite absence of clinical symptoms.
The suspicion and recognition of these imaging changes,
plus awareness of any clinical signs and symptoms, may
be an indication for more sophisticated imaging (CBCT,
MRI, nuclear medicine scan), blood testing, and consul-
tation. Blood tests should include erythrocyte sedimen-
tation rate and C-reactive protein, antinuclear antibody,
rheumatoid factor, anti–cyclic citrullinated peptide,
vitamin D, and 17b-estradiol levels.
Antiinflammatory medication such as the NSAIDs
(Naproxen, Celebrex, Feldene), as well as vitamin D
and calcium supplementation, both of which are known
to increase bone density, should be prescribed.
Colleague rheumatologists with an understanding of
this TMJ pathology should manage medications such
as methotrexate or etanercept.
17,22,23
CONCLUSION
Cases such as the 3 reported here can be found in any
orthodontic practice. If we are at fault, it is likely because
we looked at this pathology as a dental problem. Maybe
it is time that we look at TMJ arthrosis as a systemic pa-
thology. To avoid the outcome of deleterious skeletal
change and unsalvageable TMJ, the orthodontist should
be able to make an early diagnosis and early treatment
“en amont”(upstream) of the skeletal changes.
The mandible contains teeth as the end-organ for
TMJ function. This has led some within the dental pro-
fession to embrace the concept that the presence of
teeth makes the TMJ a unique articulation. This has in
the past resulted in those practitioners focusing their
diagnosis and management of TMJ disorders on the
occlusion, despite no supporting evidence.
24,25
All 3 patients were treated to a Class I functional oc-
clusion. The postorthodontic continuation of joint prob-
lems does not support the theory that Class I occlusion,
canine guidance, incisor guidance, or balanced occlusal
contact would avoid or prevent TMJ problems. Given the
cycle of TMJ arthrosis that can go from active to inac-
tive, it may mean that using a TMJ splint for pain relief
may be a matter of chance that splint use is initiated
before the remission period.
In conclusion, it is essential that TMJ arthritic disease
be discussed in dental circles as a pathologic entity in the
same way our colleagues discuss arthritic disease in or-
thopedic circles. Not doing this only exacerbates the
problem that everyone has with TMJ disorders in genera
—patients, clinicians, insurance carriers, etc—because
they do not consider TMJ pathology as orthopedic pa-
thology, but as just dental.
Further studies are necessary to determine the true
frequency of isolated TMJ arthrosis in JIA and explore
other possible causes for isolated TMJ arthrosis as well
as the optimal therapy.
ACKNOWLEDGMENTS
The author thanks Louis Cadotte (1962-2018) for
providing permission to use the records of patient 1,
Carl Bouchard for providing careful surgical treatment
and providing some photos of patients 1 and 2, and
Louis Mercuri and William Proffit for reviewing the
manuscript.
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