Odontogenic tumors

1. Ameloblastoma ,Adamantinoma,Adamento -
epithelioma, Adamanto- ameloblastoma.
Ameloblastoma has been defined as unicentric, non
functional, intermitent ingrowth, anatomically benign
and clinically persistent tumor of the odontogenic
origin. AME TP 5
It is a true benign epithelial odontogenic tumor,
Pathogenesis:
1) Cell rest of enamel organ.
2) Disturbance of developing enamal organ, dental
lamina, tooth buds.
3) Basal cell of surface epithelium of oral mucosa.
4) Epithelium of odontogenic cyst like dentigerous

2. Incidence:1% of oral tumor and 18% odontogenic tumor.
Age: 1st to 7th decade.
Sex : equally in male and female.
Site : mandible: maxilla.(5:1).
Posterior molar ramus area in mandible, post. maxilla.
Classification:
1. central or intraosseous type.
2. Peripheral or extra osseous type found in gingiva and
mucosa of alveolar process.
3. Extra oral ameloblastomas.
i. pituitary ameloblastoma/cranio-rathke’s pouch tumor.
ii.Adamentinoma of long bones(tibia ulna femur etc.)origin
unknown.
Radiological features:
1)unilocular/multilocular.2)Multilocular ameloblastoma has
soap bubble or honey comb appearance. AME P 2

3. Histological features:
1) Follicular type: contains cuboidal/columnar cells
with polimarised nuclei as pre- ameloblastic cells.
2) Plexiform type: Arranged as irregular mass (mesh
work like)
Treatment:
1) Curettage.
2) Chemical cautirization.
3) Electro- cautirization.
4) Enbloc excision.
5) Radical resection with or without reconstruction or
segmental resection. AME P 3

4. Radical resection or segmental resection.
It is considered to be the most effective method of treatment
of ameloblastoma.
A wide excision with atleast 2cms away
from the radiographic margins is advisable. The procedure is
carried out extra-orally through a submandibular approach in
case of mandible.
In a clean case primary reconstruction
with reconstruction plate, K wire ortitanium mesh etc can be
carried out to avoid facial disfigurement and scaring of the
tissue.
In case of reconstruction is postpone
for certain reasons.IMF of the remaining segment of mandible
to maxilla for a period of 3 weeks recommended.
AME P 4

5. The primary reconstruction can also
be undertaken with a ribgraft or an iliac crest graft. Iliac
crest form excellent contour of the region where as the rib
can be moulded to confirm to the facial convexity.
cortico- cancellous iliac crest graft is
considered better as it provides bulk and better
osteogenesis.
All ameloblastomas are radioresistance tumor
hence should be treated surgically.
NB: benign tumors having ectodermal and mesodermal
elements ( mixed tumors)
---- Ameloblastic fibroma.
---- Ameloblastic fibro-odontoma.
---- Odonto ameloblastoma.
Benign ectodermal origin tumor Ameloblastoma.
AME P 5

6. Dental lamina: It is the product of upper and lower epithelium
bands which divide on there deep aspect into two parallel
bands.
A buccal band known as Vetibular band
or lip furrow band and
An inner band called dental lamina.
The dental lamina is destined to produce the tooth germs.
It is therefore, tooth is a modification of GERM LAYER.
The extention of dental lamina is called successional dental
lamina and gives rise to permanent tooth buds except for the
molars.
Thus the initiation of the tooth buds occurs from dental lamina
which is derived from the oral epithelium.