1) Condylar hyperplasia is a TMJ pathology characterized by excessive, unilateral mandibular growth resulting in facial asymmetry. 2) It is classified based on the location and direction of excessive growth. Management depends on the severity of asymmetry, age, and condylar activity level. 3) For active growth, condylectomy is usually performed to arrest growth while orthognathic surgery alone is used if growth is inactive to correct occlusal and skeletal deformities. The most complex treatment combines condylectomy and orthognathic surgery.

1. Condylar hyperplasia
Presented by
Safa Basiouny
MSc, PhD Orthodontics
Lecturer of Orthoontics, Faculty of Dentistry, Tanta
University

2. Contents
Definition and incidence
1
2
3
4
5
Classification
Etiology
Diagnosis and differential diagnosis
Management

3. What is condylar hyperplasia (CH)
As described by Robert Adams (1836) CH is a TMJ pathology that is characterized by
excessive mandibular growth that almost always presents unilaterally, resulting in facial
asymmetry. The condition is slowly progressive and self-limiting, but the longer it persists
the greater the developing asymmetry and associated occlusal changes.
 Excessive growth can occur in several different locations as
An enlarged condyle
01
An elongated condylar neck
02
Outward bowing or downward growth of the
body and ramus.
03

4. Incidence
Age: Occur at any age and can continue past the growth period.
Sex: Predominantly affect women.
Side: Sex-based laterality (sex linked), with women more in RT side, men
affected more in LT side
LT
RT

5. The etiology of condylar hyperplasia is controversial and not well understood. Some
theories suggest that it is caused by
1 Trauma
2 Heredity/Intrauterine factors
3 Infections
4 Hypervascularity
5 Familial history
6 Hormonal (estrogen)
Etiology

6. Classification
Obwegeser and Makek classification
Wolford, Movahed, and Perez classification
01
02

7.  Type I (Hemi-mandibular Elongation)
Clinical findings
 Chin deviation towards contralateral side
 Midline shift to contralateral side
 Ipsilateral class III malocclusion on the same side.
 Lingual deviation of contralateral mandibular molars
 Possible posterior crossbite
Anatomical finding
 Excessive growth in the horizontal vector
 Condyle often unaffected
 Elongated mandibular ramus
 Misshapen and slender condylar neck

8. Anatomical finding
 Excessive growth in the vertical vector
 Enlarged and often irregularly shaped condylar head
 Neck of condyle can be thickened and/or elongated
 Type II (Hemi-mandibular Hyperplasia)
Clinical finding
 Sloping rima oris (comisures) with minimal chin deviation
 No midline shift
 Possible open bite
 Supraeruption of maxillary molars on affected side and severe
OC

9.  Type III (Hybrid)
Clinical findings
 Chin deviation towards contralateral side with a sloping
rima oris
 Midline shift
 Possible open bite and/or cross bite
Anatomical finding
 Excessive growth in both vectors
 Enlarged condylar head, neck and ramus
 Irregularly shaped condylar head, neck and/or ramus

10. Anatomical finding
Clinical finding
Age of
onset
Type
• Bilateral mandibular
elongation
• No midline deviation
• Prognathism and Class III
occlusion
• Accelerated and prolonged
growth
Pubertal
growth
Type
IA
• Unilateral mandibular
elongation
• Chin deviation towards
contralateral side
• Midline shift to contralateral
side
• Lingual deviation of
contralateral mandibular
molars
• Possible posterior crossbite
• Ipsilateral Class III occlusion
Type
IB
• Excessive growth in the horizontal vector
• Condyle often unaffected
• Bilateral elongated mandibular head, neck
and ramus
• Misshapen and slender condylar neck

11. Anatomical finding
Clinical finding
Age of
onset
Type
• Excessive growth in the vertical vector
• Condylar enlargement without horizontal exophytic
growth of condyle
• Enlarged and often irregularly shaped condylar head
• Neck of condyle can be thickened and/or elongated
• Unilateral vertical elongation
of face
• Sloping rima oris with
minimal chin deviation
• Supraeruption of maxillary
molars on affected side
• Possible open bite
• No midline shift
Two thirds
of cases
begin in
second
decade
Type
IIA
• Excessive growth in the vertical vector
• Condylar enlargement with horizontal exophytic
growth off condyle (osteochondroma)
• Enlarged and often irregularly shaped condylar head
• Neck of condyle can be thickened and/or elongated
Type
IIB

12. Anatomical finding
Clinical finding
Age of
onset
Type
- Caused by benign tumor growth
- Osteomas, neurofibromas, fibrous dysplasia, giant cell
tumor, chondroma, chondroblastoma, etc.
• Unilateral facial
enlargement
No
specific
age
Type III
-Caused by malignant tumor growth
-Caused by chondrosarcoma, multiple myeloma,
osteosarcoma, Ewing sarcoma, and metastatic lesions
Type IV

13. Diagnosis
Clinical
Radiographic Nuclear imaging
Histopathology

14. A. Panoramic & cephalometric
 Serial panoramic and cephalometric radiographs (6- to 12-
month intervals) can be used to determine if the condition is
active.
 On plain radiographs the following observed:
Type
II
1. Double mandibular bodies observed in profile
radiograph.
2. Anteroposterior radiograph will show evidence
of maxillary and OC
3. Difference in height of gonial angles evident on
panoramic and anteroposterior radiographs
and CT
4. Loss of the antegonial notch and asymmetry of
the mandibular body.
5. The affected condylar head is larger and the
neck is longer than on the contralateral side.
Type Imaging charecteristics
Type
I
1. Panoramic radiograph or CT will show changes
in length and condylar volume
2. PA radiograph will show evidence of
mandibular lateral deviation and mild maxillary
canting
3. No differences in mandibular ramus length
(condylion to gonion) or gonial angle height.
Type
III
Combination

15. B. CBCT
 The following measurement can be taken and
compared to the contralateral side
Measurement Description
Condylar
length
In the sagittal view, a tangent to the
posterior ridge of the mandibular ramus
and a perpendicular tangent to it from
the deepest part of the mandibular
notch are traced; the length is
measured from the most superior
contour of the condyle to a medium
point located in the perpendicular plane
that goes from the mandibular notch to
the tangent to the posterior ridge of the
mandibular ramus

16. Measurement Description
Mandibular
ramus length
In the sagittal view of 3D reconstruction, a
line perpendicular to the Frankfort plane and
extended from the deepest point of the notch
to the inferior ridge of mandibular body is
traced
Ramus width In the sagittal view of 3D reconstruction, a
line parallel to the Frankfort plane and
extending from the deepest point of the
anterior contour of the mandibular ramus to
the posterior ridge is traced
Mandibular
body length
In the sagittal view of 3D reconstruction, a
line that goes from the bone–tissue gonion to
the bone–tissue pogonion is traced
B. CBCT
 The following measurement can be taken and
compared to the contralateral side

17. Measurement Description
Deviation of
midpoint of
symphysis
In the frontal view of 3D reconstruction, the
distance from the point of the menton to a
line going from the lower third, projected
from the middle part of the apophysis crista
galli perpendicular to the bizygomatic line,
is measured in millimeters
B. CBCT
 The following measurement can be taken and
compared to the contralateral side

18.  Skeletal scintigraphy is the gold standard to evaluate
growth activity in the condylar head
 Idea:
 Capable of providing physiological details of CH using
radionuclide-labeled tracers which is injected and
absorbed into hydroxyapatite crystals and calcium in
the bone. The bone is then scanned, and the hyperplastic
condyle is quantitatively compared to the contralateral
side.
Planar
scintigraphy
SPECT
(Single
photon
emission
computed
tomography)
PET(Positro
n emission
Tomography
)
Radionucleotid
e
technetium-
99m-labelled
methylene
diphosphonate
(99mTc-MDP)
technetium-
99m-labelled
methylene
diphosphonate
(99mTc-MDP)
[18F]-fluoride.
Produced
image
2D 3D 3D
Sensitivity Less than
SPECT
higher
sensitivity
less
Interpretation Descriptive
(hot spot)
Quantitative Quantitative
Nuclear imaging

19.  Interpretation of SPECT
Uptake levels Indication
Difference in uptake levels of
less than 10%
normal condyles or individuals
without progressive asymmetry
Differences greater than 10% active growth due to CH.
uptake value greater than 55% condylar hyperplasia
 Comparison of the uptake with normal standards by
age
A ratio of uptake to 4th lumbar vertebra (standard bone for
scanning purposes) is calculated. The ratio is then compared to
normal standards by age
Ratio
Age
2-1.85
0-2
1.85-1.65
2-5
1.65-1.30
5-10
1.30-1.10
10-15
1.10-0.7
15-20
ᐸ0.7
20
 Comparison of the uptake levels between two
sides

20. Both condylar hyperplasia and condylar
osteochondroma
showed a cartilage cap that covered the
surface of the
condyle. The cartilage cap was divided into
four layers:
Histopathologic features
H&E staining showed that the cartilage cap that
covered the surface of the condyle was divided into
four layers:
• The fibrous layer,
• Undifferentiated mesenchyme layer,
• Cartilage layer including pre-hypertrophic and
hypertrophic
• Chondrocytes and the calcified cartilage layer

21. Differential diagnosis
1
2
1
2
Mandibular prognathism
without CH
Acromegaly
Congenital or acquired
facial asymmetry
unrelated to the TMJ
Other TMJ pathology as
osteochondroma,
osteoma, contralateral
condylar resorption.
Bilateral
Unilateral

22. ONSET CLINICAL FINDINGS IMAGING FINDINGS
Condylar hyperplasia 13-30 year -Elongation or enlargement of
the hemimandible Mandibular
asymmetry away from the
affected side
-Malocclusion (crossbite/open
bite)
-Slowly progressive
-Enlargement of the condylar head and
elongation of the condylar neck
-Scintigraphy positive
Condylar tumors:
osteochondroma,
osteoma, chondroma,
osteoblastoma
40.5 years Elongation or enlargement of
the hemimandible
–Mandibular asymmetry toward
the contralateral side
-Malocclusion (crossbite/open
bite)
-Slowly progressive
-“Mushroom-shaped” mass associated
with the condylar head
-Scintigraphy positive
Differential diagnosis

23. ONSET CLINICAL FINDINGS IMAGING FINDINGS
Condylar hypoplasia/
degeneration
1st-6th
decades
-Shortening of the ipsilateral
hemimandible
-Mandibular asymmetry toward the
affected side
-Malocclusion (premature contact on
the affected side)
-Slowly progressive
-Degenerative changes in the condylar
head
-Scintigraphy positive or negative
(consistent with DJD)
Condylar fracture Any -Shortening of the ipsilateral
hemimandible
-Mandibular asymmetry toward the
affected side
-Acute
-Evidence of fracture (acute) –Degenerative
changes in the condylar head (old)
-Scintigraphy negative
Craniofacial
syndromes:
hemifacial microsomia
Congenital -Shortening of the ipsilateral
hemimandible
-Mandibular asymmetry toward the
affected side
-Slowly progressive
-Variable degrees of DJD to absence of the
condyle
-Scintigraphy negative
Differential diagnosis

24. CH treatment options are detailed from the simplest, least invasive to most
complex procedures:
Treatment of CH
01
Condylectomies
(if active growth)
02
Orthognathic
(if not active)
03
Condylectomy
and
orthognathic
(if active growth)

25.  Treatment depends on:
Treatment of CH
3 The level of asymmetry and malocclusion
2 Age (growing versus adult)
1 Mandibular condyle activity (active
versus non active hyperplasia)

26. Condylectomy
Low or proportional High
Low condylectomy is used for removing TMJ tumors. Used for active CH
Indicated in type II CH Indicated in type I CH
Involves not only removing the hyperactive portion, but also
restoring the occlusal plane by resecting the necessary
quantity of bone to match the non-affected side in case of mild
occlusal canting.
The hyperplastic portion of the condyle is visually identified
(approximately the superior 4–5 mm of the condyle) and is
resected, and the apparent normal condyle is left in place.
Disadvantage:
If condylectomy is performed on the affected side before
cessation of condyle growth, there is risk of a mandibular
shift to the affected side because the condyle on the
unaffected side will continue normal growth.
Disadvantage:
Less stable than low condylectomy. Most patient require
second surgery because the condyle may continue to grow.
Advantages:
 Offers highly predictable and stable outcome.
 If carried out early in the process, secondary dental and maxillary compensations may be avoided.
 Effective method for avoiding unnecessary secondary surgeries in active condylar hyperplasia.

27. Orthognathic surgery only
Indication:
 Inactive growth of CH
 Type I condylar hyperplasia (hemi-mandibular elongation).
Disadvantage:
 Surgery is delayed until growth is complete, which could be in the early to mid-20s.
 The longer the abnormal growth is allowed to precede, the worse the facial
deformity, asymmetry, occlusion, and dental compensations will become, in addition
to warping of the mandible and ipsilateral excessive soft tissue development.
 Adverse effects on mastication, speech, and psychosocial problems.

28. 05
04
03
02
01 BSSO or vertical ramus osteotomy on the
affected side.
Unilateral ramus osteotomies
• Patients with severely prognathic profiles
• Patients in whom unilateral osteotomies could
possibly lead to excessive rotation of the
unaffected condyle.
Bilateral osteotomies
According to the need to level occlusal plane
Lefort I osteotomy
To correct any residual chin deviation
Genioplasty
Involves facial recontouring with reshaping of
mandibular body and nerve repositioning. Indicated
for most type II patients
Mandibular limbic reduction
Orthognathic surgery only

30. Condylectomy and orthognathic surgery
 The most complex surgical treatment for CH.
Indication:
1. To prevent relapse after surgery because condylar growth may not be complete at the time of
surgery. The combination provides more stable results.
2. If the condition is active with severe malocclusion and asymmetry: perform a growth
arresting procedure (high condylectomy) combined with orthognathic surgery.
3. Most patients with hybrid type

31. CH
Growing
Condylectom
y
Growth
observation
Adult
Active
Condylectom
y+
orthodontic
Severe OC
Mild to
moderate
OC
Not active
Orthognathi
c
Condylectom
y +
orthognathic
Severe
class III
Severe
class III
Mild to
modetate
class III
Mild to
modetate
class III
Pre ortho
Two jaw surgeries
Post ortho
Pre ortho
One jaw surgery
Post ortho
pre ortho
One jaw surgery
Post ortho
Ortho only
Orthodontic

32. References

33. HANK OU