1. IDIO PATHIC CO N DYLAR RESO RPTIO N AN D ITS IMPACT O N
O RTHO DO N TIC TREATMEN T
2016
M OHAM M ED ALM UZIAN

2. Introduction
 Idiopathic condylar resorption (ICR), also known as condylar lysis and condylar
atrophy is a condition affecting the size and morphology of the mandibular condyles (Papadaki,
Tayebaty et al. 2007).
 It affects females almost exclusively between ages 15-35 yrs with a peak around the
pubertal growth spurt (Huang, Pogrel et al. 1997), and because of this it has also been termed
“cheerleader’s syndrome”.
 Condylar resorption was first reported by Burke in 1961(Burke 1961) who described it
as an “acquired condylar hypoplasia” and has since been recognised as a unique clinical entity
in 1977 (Rabey 1977).
Incidence
 Adult condylar resorption appears to be rare. There is no current evidence to state that
the prevalence of condylar resorption and diminished mandibular growth in children exceeds
the rare incidence in adults.
 Arnett and Tamborello 1990: Reported 10 cases of progressive Class II malocclusion,
secondary to condylar resorption in approximately 800 dentofacial deformities examined over
a 10 year period.
Remodeling of the TMJ
Functional and Dysfunctional Remodeling are two types of TMJ remodeling, they represent a
spectrum of articular surface changes with condylysis being the most severe, resulting in near
or total loss of the condyle.
Functional Remodeling (FR): This is characterized by morphological changes involving the
articular structures of the joint that are not associated with any significant alterations in the
mechanical function of the joint or occlusion. FR is identified by:
 TMJ morphologic change
 Stable ramus height
 Stable occlusion
 Normal growth

3. Dysfunctional Remodeling (DR) / Condylar Resorption: This is characterized by remodeling
which adversely affects the mechanical function of the joint and occlusion. It is associated
with excessive or sustained physical stress to the articular structures, which exceeds normal
adaptive capacity or exceeds a decreased adaptive capacity. DR is distinguished by:
 TMJ morphologic change (decreased condylar head volume)
 Decreased ramus height
 Progressive mandibular retrusion (adult)
 Decreased growth rate (juvenile)
 DR (Condylar Resorption) causes the mandible to become progressively retrusive in
adults
Aetiologic theories
 The cause and pathogenesis of ICR remains unclear (Papadaki, Tayebaty et al. 2007)
and in the majority of cases there is no clear identifiable cause.
 Due to the strong predilection for females it is widely believed that a hormonal cause
is likely.
 Two main theories have been
hypothesised by various groups:
A. The Arnett group (Arnett, Milam et
al. 1996) proposed a link with increased
loading of the TMJ and subsequent pressure
resorption, which may occur after
orthodontic treatment, orthognathic surgery,
parafunction or trauma (Arnett, Milam et al. 1996). Chong and colleagues (Chuong and Piper
1993, Chuong, Piper et al. 1995) suggest that the condition is similar to that of avascular
necrosis of the femoral head (Perthe’s disease) which is characterised by damage to vascular
structures within the bone resulting in ischemia and osteonecrosis of the femoral head.

4. B. More recently they investigated the association
between low estrogen levels (17beta-estrogen) and ICR
(Gunson, Arnett et al. 2009) and found strong evidence
for this as a major etiologic factor. It has also been
shown that components of the TMJ contain receptors
for estrogen in varying degrees which makes the
hypothesis plausible (Abubaker, Raslan et al. 1993).
Investigations by Wolford, who has written extensively
on ICR, is largely consistent with the Arnett groups findings. He describes the pathophysiology
cascade of ICR (Wolford and Cardenas 1999):
Risk factors (Wolford and Cardenas 1999), (Arnett 2013)
1. Age and gender:
o Female – affects F>M (9:1)
o 15-35 years of age – associated with peak growth and hormonal activity
2. Local and systemic disease such as osteoarthritis and rheumatoid arthritis
 Autoimmune disorders
 Endocrine disorders
 Nutritional disorders (Anorexia nervosa)
 Metabolic diseases
 Infectious diseases
 Cardiovascular diseases
 Blood dispraises
 Excessive psychological stress
3. Occlusal factors:
o High MP angle – increased load on mandibular condyle, rarely develops in low angle
cases
o High OP angle – increased load on mandibular condyle

5. o Posteriorly inclined condyle
o High angle sk class II malocclusions - rarely develops in sk class IIIs
4. Hormones
o Low endogenous estrogen levels (17beta-estradiol) (Gunson, Arnett et al. 2009) - High
levels of exogenous Ethinyl Estradiol (EE) and Progestin – both found in oral contraceptives
cause a negative feedback loop to reduce levels of naturally occurring 17beta-estradiol. This is
thought to modify the adaptive process of the condyle to abnormal loading. 17beta-estradiol is
osteoprotective as it inhibits osteoclastic activity and thus reduced levels can predispose to
bone resorption.
o Prolactin – “It is likely that prolactin contributes to the accelerated condylysis”
o Corticosteriods – Association with joint resorption (Hypothetical at this stage)
5. Mechanical factors:
o Articular disk displacement
o Parafunction
o Macrotrauma
o Unstable occlusion
o Increased condylar loading
o Pre-treatment condylar atrophy
6. Orthodontics
o Kato and colleagues(Kato, Hiyama et al. 1999) reported that orthodontic treatment
alone can cause condylar resorption after treating a 12 yr old girl with impacted canines.
Whether the condylar resorption was caused by the orthodontic treatment is unclear.
7. Orthognathic surgery, magnitude and direction of BSSO advancement
o Upward and forward rotation during BSSO is associated with high risk.
o BSSO advancement and Maxillary osteotomies will cause a sudden repositioning of the
condyle in the fossa, which increases the mechanical load in the joint (Arnett, Milam et al.
1996).
o In most patients, adaptation to this change occurs, but in some the remodelling capacity
of their TMJs is impaired and their condyles will resorb.

6. o Arnett et al showed that over-seating the condyle in the fossa during BSSO can cause
compression and result in dysfunctional remodelling of the joint (Arnett, Milam et al. 1996).
o Patient who had a surgery with IMF have a higher risk
Diagnosis
Based on history, clinical examination and imaging.
1. History
 Progressive worsening of occlusion and aesthetics
 development of AOB.
 If resorption is asymmetric, then Md deviation and class II relationship will occur on
the more affected side.
 TMJ pain can be a feature during the active phase but not always (25% of patients may
have no pain (Wolford and Goncalves 2015)).
 Presence of the above risk factors may also be present in the patient’s history.
2. Clinical examination
 Patients will usually have normal
range of mouth opening when the
condition is in quiescence.
 However speech and chewing
function is often affected,
 occasionally breathing due to
soft tissue collapse into the airway
(Posnick 2013).

7. 3. Imaging
Common lateral cephalometric radiographic
findings include the following (Wolford and
Cardenas 1999):
1. Skeletal and occlusal Class II
relationship
2. Anterior open bite
3. High mandibular occlusal plane angle
4. High mandibular plane angle
5. Decreased vertical height of the ramus
6. The lower incisors may appear overangulated
7. A significant decrease in the oropharyngeal airway can occur in the more severe cases.
8. Intra-capsular
Common lateral cephalometric findings in a bilateral TMJ ICR include:
 Skeletal and occlusal Class II deformity
 Anterior open bite
 High mandibular occlusal plane angle
 High mandibular plane angle
 Decreased vertical height of ramus
 Lower incisors may appear over-angulated
 Significant decrease in the oropharyngeal airway (in severe cases)
Findings in a unilateral case:
 Unilateral skeletal and occlusal Class II deformity
 Vertical height difference at the mandibular inferior border/ramus/OP
 Open bite on the contralateral side
 A P-A cephalogram may show worsening asymmetry
Method of imaging
I. MRI (Wolford, 2015): MRI findings include:
 Decreased condylar volume

8.  Anterior disc displacement with or without reduction on opening
 Extreme thinness or loss of continuity of cortical bone on the condyle head
 Thick amorphous soft tissue occupying the space between the condyle and fossa
II. Serial lateral cephalograms will demonstrate slow but progressive retrusion of the
mandible during the active phase.
III. The OPG can be used for gross examination of the condyle and will appear to have lost
mass relative to the rest of the mandible and it can appear thin or shortened with flattening of
the superior or anterior curvature(Hoppenreijs, Stoelinga et al. 1999). In many cases, there will
be a distal inclination of the condylar neck(Hoppenreijs, Freihofer et al. 1998).

9. IV. The value of radioisotope examination as part of the diagnosis of ICR is disputed. This
type of scan (usually done with technicium-99) is difficult to interpret because various types
of TMJ conditions will show a high level of uptake, however others feel it has some diagnostic
value(Huang, Pogrel et al. 1997).
Management
 There are two important aspects when planning the correction of the existing
dentofacial deformity: (1) ensuring that the resorption process is inactive and (2) treating the
deformity in such a way that the loads on the condyles are not increased.
 Treatment of ICR is controversial.
 Orthognathic surgery has been attempted to manage
 ICR, but the relapse rate is high, especially if the process is active at the time of
treatment or if it becomes reactivated during the postoperative period. Treatment modalities
currently used:
1. Conservative treatment (Van Damme and Merkx 1994, Huang, Pogrel et al. 1997,
Hoppenreijs, Stoelinga et al. 1999)
 Ideally post-active phase
 “Compensation” using splints, orthodontic tx with and without exo, restorative tx. Any
orthodontic treatment, such as Class III elastics, that increases the loading of the condyles (and
could reinitiate the condylar resorption process) should be avoided.
 Shown to be stable
 Occlusal splints should be used when there is pain and dysfunction in the TMJ and also
for a period prior to surgical correction (Arnett and Gunson).
2. Mx osteotomy only – to reduce risk of reactivation by avoiding condylar
trauma/overloading(Arnett GW 1990)
 Ideally post-active phase
 Does not always provide good aesthetic result (Hoppenreijs, Stoelinga et al.
1999)(Tominaga, 2016)
 Reactivation less likely
3. BSSO +/- Mx osteotomy
 Ideally post-active phase

10.  Many authors report high rates of relapse (Van Damme and Merkx 1994, Huang, Pogrel
et al. 1997, Hoppenreijs, Stoelinga et al. 1999). Even inactive condylar resorption can be
reactivated by BSSO and Le Fort I osteotomy(Hoppenreijs, Freihofer et al. 1998).
 BSSO will increase the active mandibular length and thus increase the load on the
condyle.
 All studies show that surgery of mandibular advancement causes a lateral, torque and
backward movement of the condyles, all harmful to the condyles. What are the possible
solutions to avoid failures? Patient preparation before surgery and surgery simulation with an
articulator, condylar position control during surgery, working with surgeons to achieve a
condylar portion stabilization system (with the CAD), quickly set up a mobilization of the
mandible by physiotherapy
 A systematic review showed that there was a substantial consistency among studies,
however, that young, female patients with mandibular deficiency and high mandibular plane
angle, submitted to surgical counterclockwise rotation of mandibular segments, were more
prone to a higher risk for condylar resorption after BSSO (Mousoulea, 2016)
4. A segmental Le Fort I bilateral osteotomy, ramus increasing length inverted L-
osteotomy, and genioplasty combined with orthodontic treatment
5. Articular disk anchorage (mini-anchor) followed by BSSO advancement(Wolford
and Goncalves 2015)
 Ideally post-active phase
 BSSO advancement is stable
 Normal TMJ function and ROM

11. 6. Condylectomy followed by CCG (Wolford and Goncalves 2015) (costo-chondral
graft)
 Condylectomy will cease active phase
 CCG is ideal autologous material
 Fixed rigidly
 Slight posterior open-bite left to allow some vertical relapse
 Aggressive physical therapy required
 Good results
7. Condylectomy followed by alloplastic total joint prosthesis (Wolford and Goncalves
2015)
 Condylectomy will cease active phase
 Should be used with fat grafts around prosthesis
 Aggressive physical therapy required
 As with any prosthetic joint, will need replacement after a number of years
 Most stable
 Considered superior to CCG
It seems that orthognathic surgery alone is not an ideal treatment for ICR. Reported long-term
results are not stable, and resorption may proceed or be triggered if quiescent preoperatively.

12. The role of the orthodontist before orthognathic surgery is to prepare upper and lower teeth to
an ideal arch form that will maximize occlusal contact in a normal Class I occlusion
postoperatively to minimize joint loading and potential for relapse.

13. References
Abubaker, A. O., W. F. Raslan and G. C. Sotereanos (1993). "Estrogen and progesterone
receptors in temporomandibular joint discs of symptomatic and asymptomatic persons: a
preliminary study." J Oral Maxillofac Surg 51(10): 1096-1100.
Arnett, G. W. (2013). "Risk Factors in the Initiation of Condylar Resorption." Semin Orthod
19(19): 81-88.
Arnett, G. W. and M. J. Gunson "Risk Factors in the Initiation of Condylar Resorption."
Seminars in Orthodontics 19(2): 81-88.
Arnett, G. W., S. B. Milam and L. Gottesman (1996). "Progressive mandibular retrusion--
idiopathic condylar resorption. Part I." Am J Orthod Dentofacial Orthop 110(1): 8-15.
Arnett, G. W., S. B. Milam and L. Gottesman (1996). "Progressive mandibular retrusion-
idiopathic condylar resorption. Part II." Am J Orthod Dentofacial Orthop 110(2): 117-127.
Arnett GW, T. J. (1990). "Progressive class II development: female idiopathic condylar
resorption. ." Oral Maxillofac Surg Clin North Am.(2): 699–716.
Burke, P. H. (1961). "A case of acquired unilateral mandibular condylar hypoplasia." Proc R
Soc Med 54: 507-510.
Chuong, R. and M. A. Piper (1993). "Avascular necrosis of the mandibular condyle-
pathogenesis and concepts of management." Oral Surg Oral Med Oral Pathol 75(4): 428-432.
Chuong, R., M. A. Piper and T. J. Boland (1995). "Osteonecrosis of the mandibular condyle.
Pathophysiology and core decompression." Oral Surg Oral Med Oral Pathol Oral Radiol Endod
79(5): 539-545.
Gunson, M. J., G. W. Arnett, B. Formby, C. Falzone, R. Mathur and C. Alexander (2009).
"Oral contraceptive pill use and abnormal menstrual cycles in women with severe condylar
resorption: a case for low serum 17beta-estradiol as a major factor in progressive condylar
resorption." Am J Orthod Dentofacial Orthop 136(6): 772-779.
Hoppenreijs, T. J., H. P. Freihofer, P. J. Stoelinga, D. B. Tuinzing and M. A. van't Hof (1998).
"Condylar remodelling and resorption after Le Fort I and bimaxillary osteotomies in patients
with anterior open bite. A clinical and radiological study." Int J Oral Maxillofac Surg 27(2):
81-91.
Hoppenreijs, T. J., P. J. Stoelinga, K. L. Grace and C. M. Robben (1999). "Long-term
evaluation of patients with progressive condylar resorption following orthognathic surgery."
Int J Oral Maxillofac Surg 28(6): 411-418.
Huang, Y. L., M. A. Pogrel and L. B. Kaban (1997). "Diagnosis and management of condylar
resorption." J Oral Maxillofac Surg 55(2): 114-119; discussion 119-120.

14. Kato, Y., S. Hiyama, T. Kuroda and T. Fujisaki (1999). "Condylar resorption 2 years following
active orthodontic treatment: a case report." Int J Adult Orthodon Orthognath Surg 14(3): 243-
250.
Papadaki, M. E., F. Tayebaty, L. B. Kaban and M. J. Troulis (2007). "Condylar resorption."
Oral Maxillofac Surg Clin North Am 19(2): 223-234, vii.
Posnick, J. C. (2013). Orthognathic Surgery: Principles and Practice, Elsevier Health Sciences.
Rabey, G. P. (1977). "Bilateral mandibular condylysis-a morphanalytic diagnosis." Br J Oral
Surg 15(2): 121-134.
Van Damme, P. A. and M. A. Merkx (1994). "Condylar resorption after orthognathic surgery."
J Oral Maxillofac Surg 52(12): 1347-1348.
Wolford, L. M. and L. Cardenas (1999). "Idiopathic condylar resorption: diagnosis, treatment
protocol, and outcomes." Am J Orthod Dentofacial Orthop 116(6): 667-677.
Wolford, L. M. and J. R. Goncalves (2015). "Condylar resorption of the temporomandibular
joint: how do we treat it?" Oral Maxillofac Surg Clin North Am 27(1): 47-67.