TMJ Pathology & Diagnosis First Lecture Flashcards
Congenital or Developmental
Disorders
(4)
Aplasia
Hypoplasia
Hyperplasia
Neoplasia
Aplasia
What is it?
— is the most common
developmental defect.
Unilateral or bilateral?
— is often affected
(2) on opening may occur
Rare
More SEVERE than — !
Faulty or incomplete development of the cranial
bones or mandible.
Lack of condylar growth
Either
Auditory apparatus (i.e. Pinna of
ear deformed)
Occlusal shift & deviation
Hypoplasia
Developmental/Congenital
Anomalies affecting TMJ
Aplasia-
Lack of condylar growth is the
most common developmental defect.
Occlusal shift & deviation on opening may
occur. Rare
Treatment of
Condylar Aplasia
(3)
Osteoplasty
Correction of malocclusion
Other surgical treatment possible
depending on function and
esthetics
Hypoplasia
(4)
Incomplete development/underdevelopment of the cranial bones or the
mandible.
Congenital or acquired (i.e. Treacher-Collins syndrome).
Growth is normal but proportionately reduced & less severe than in
aplasia
Condylar hypoplasia can be secondary to trauma.
Treacher-Collins syndrome:
mandibulofacial dysostosis
(4)
- Downward-slanting eyes
- Notched lower eyelids
- Underdeveloped midface
- Deafness
Mandibular Hypoplasia:
High risk for
obstructive sleep
apnea
Mandibular Hypoplasia
Post-treatment with
mandibular advancement
surgery (bilateral sagittal
split osteotomy)
skipped
Condylar Hypoplasia
(2)
Congenital: (2)
Acquired: (6)
Unilateral or bilateral
idiopathic, early onset
forceps deliveries, trauma
especially after jaw fracture, radiation,
infection, circulatory disorder, endocrine
disorders
Condylar Hypoplasia
What is it?
Can be secondary to…
Growth is normal but proportionately reduced & less severe than in
aplasia
Condylar hypoplasia can be secondary to trauma.
Pt. fractured R. condyle at age 6. Panorex- age 15
Condylar
Hypoplasia
Clinical
Symptoms
If unilateral:
(3)
Facial asymmetry
Limitation of lateral
excursion
Mandibular midline
shift
Hyperplasia
What is it?
(2)?
— increase in the number of
normal cells.
Localized:
Mandibular —
Overdevelopment of cranial bones or mandible.
Congenital or acquired.
Non-neoplastic
condylar hyperplasia
prognathism
Mandibular prognathism –
excessive size of
mandible causing protrusion of chin but normal
condyle size, shape, & function
Mandibular Hyperplasia
tx (3)
LeForte I Osteotomy
Bilateral Sagittal osteotomy
Chin Augmentation
Condylar Hyperplasia
Clinical Symptoms
If Unilateral growth, it will cause:
(2)
- A progressive crossbite on the
contralateral side - Open bite in adults
Treatment of Condylar
Hyperplasia
(5)
Leave alone
Wait until after mandibular growth is completed
Orthognathic surgery & possible osteotomy of enlarged
condyle
Orthodontics
Symptomatic care
Coronoid Hyperplasia
(3)
Coronoid Impingement may result from
benign overgrowth of the coronoid
process
May result in limited jaw opening
Visible on Panorex, CBCT, MDCT or MRI
Unilateral Condylar Hyperplasia
creating malocclusion
Transpharyngeal projection:
Condylar head is enlarged,
and the neck is thick.
Neoplasia
What is it?
RARE as an underlying
cause of —.
–% of malignant
neoplasias (breast,
prostate, lung
cancers)metastasize to
the mandible
can affect …
Benign, malignant, or
metastatic from a
distant site.
Uncontrolled growth of
abnormal tissue.
TMD
1
condyle (I.e.
osteoma, fibrous
dysplasia,
chondrosarcoma, benign
giant cell tumor)
OSTEOCHONDROMA
R L
Benign, Solitary Osteochondromas (OCs) arise in response
to an event (e.g. trauma, X-radiation) [1] rather than as
a true neoplasm. Typically, OCs represent –% of all
bone tumors and ~–% of benign bone tumors
10-15
35
OSTEOCHONDROMA
* OCs generally occur in …
* Bones that form from a — are susceptible to single or
multiple osteochondritic lesions.
* This species of bone tumor frequently remains
asymptomatic until they become large enough
to interfere with …
young adults (~30 y/o),
but also appear during middle age or later
(~≥ 50y/o).
cartilage anlagen
(e.g., mandible)
mandibular function (i.e.
opening, lateral excursion) or cause a shift in
the midline & malocclusion.
Neoplasia
Rare in — but more
common in —
Benign:
Malignant:
Consider (2)
condyle, ramus
does not usually
destroy bony margins
Usually destroys
bony margins- Examine cortical
outline of mandible on Panorex
parotid and regional
carcinomas
Hypermobility Disorders: 2 types
of TMJ Dislocations:
Hypermobility disorders include two types of TMJ dislocations
in which the
disc-condyle complex is positioned anterior to the
articular eminence and is unable to return to a closed position
without a specific maneuver by the patient (i.e., subluxation or
partial dislocation) or by the clinician
Subluxation
(3)
Partial or incomplete condylar
dislocation during wide mouth opening
but the patient can close voluntarily
Usually accompanied by a joint sound
(soft pop or click)
May result from anatomical
difference , habit, or trauma
