Dr. Özkan ADIGÜZEL

1. RESORPTION OF TEETH
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2. Dental hard tissues are resorbed by
multinucleate cells called ODONTOCLASTS
or DENTINOCLASTS.
They are considered to be same type as
osteoclasts because they possess the same ultra
structure and histochemical characteristics.
However, dentinoclasts or odontoclasts may
contain fewer nuclei than osteoclasts.
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3. Classification:
1. Physiological
2. Pathological
a) External root resorption
a.1) Resorption due to trauma-surface ,
inflammatory and replacement resorption
a.2) Resorption due to pulp or apical pathology
a.3) Resorption due to pressure
b) Internal root resorption
c) Idiopathic root resorption
Recently, a clinical oriented classification has been
developed
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4. This new classification is based on two
requirements, namely-
*injury to protective tissues: chemically or
mechanically
*stimulation: by infection or pressure
Injury is related to non mineralized tissue
covering the external surface of the root-ie.,
pre cementum or internal surface of the
root canal-ie., pre dentine.
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5. Injury:
Mechanical- dental trauma, surgical procedures,
excessive pressure from tumours or impacted teeth
Chemical-bleaching with 30% H2O2
Following injury denuded mineralized tissue become
colonized by multinucleated cells which initiate the
resorption process.
However, without stimulation, resorption process end
spontaneously and reparative changes occur.
Therefore, continuation of the resorption process depend
on continuous stimulation by either pressure or
infection
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6. Present classification is based on different
stimulation factors.
It is clinically oriented as the resorption
process can be reversed by removing the
stimulation factor.
Classification
1. Pulpal infection root resorption
2. Periodontal infection root resorption
3. Orthodontic pressure ,, ,,
4. Impacted tooth/tumour ,, ,,
5. Ankylotic root resorption
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7. Pulpal infection root resorption
*most common stimulation factor
*following injury to pre cementum or pre
dentine inflammatory process within peri
radicular or pulpal tissue initiate external
or internal resorption
*radiolucency is observed in the external root
surface of dentine & bone, or in the internal
root canal dentinal wall
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8. Treatment:
Internal resorption- pulptectomy: to remove
granulation tissue/ blood supply of resorbing
cells
External resorption- pulptectomy: critical to
remove bacterial stimulation from dentinal
tubules using calcium hydroxide.
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9. Periodontal infection root resorption
*external root resorption may occur apical
to the epithelial attachment, followed by
bacterial stimulation originating from
periodontal sulcus.
*injury may be caused by dental trauma,
bleaching agents, orthodontic treatment
or periodontal procedures
*bacteria penetrate the patent dentinal
tubules coronal to epithelial attachment
and exist apical to ,, ,, .
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10. *radiologically, seen as a single resorption
lacuna (radiolucency) at the crestal bone
level.
*treatment: As long term bacterial removal
from the periodontal sulcus is not practical,
effective therapy is to expose the resorptive
lacunae orthodontically or surgically to
remove granulation tissue followed by
restoration with composite.
Endodontic therapy is only necessary if the
resorption process extend in to pulp.
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11. Orthodontic pressure resorption
*pressure applied to roots during tooth
movement can cause apical root resorption.
Continuous pressure stimulate resorbing
cells of the apical third of the root, leading
to shortening of the root.
*teeth are usually vital if undue pressure is
not applied
*located at apical one third of the root, but no
signs of radiolucency can be observed.
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12. *treatment: removal of the pressure source is
usually sufficient. Operative procedures are
not necessary.
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13. Impacted tooth/ tumour pressure resorption
*impacted tooth pressure resorption can be
observed during eruption of the permanent
dentition Max 3….Max2, Man 3….Man 2.
*tumours impinging on the tooth roots can
cause pressure resorption. Tumours that
produce resorption are slow growing
lesions as ameloblastoma, giant cell
tumours ect.,
* usually, asymptomatic with vital pulps
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14. *radiologically, resorption area is located
adjacent to the stimulation factor.
Radiolucencies are not observed as
infection is not involved. The site is filled
with stimulation factor.
*treatment:surgery to remove the stimulation
factor
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15. Ankylotic root resorption
*in severe traumatic injuries eg intrusive
luxation or avulsion injury to the tooth
surface may be large so that healing with
cementum is not possible and the bone
comes in contact with root surface without
periodontal ligament. This is known as
dento-alveolar ankylosis.
*Although, there is no stimulation factor and
the process proceeds as a result of direct
bone attachment to dentine, the term
ankylotic resorption is used.
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16. *radiologically, the resorption lacunae are
filled with bone and the periodontal
ligament space is missing. No radiolucent
area is observed.
*treatment: as there is no stimulation to
remove, no predictable treatment is
available.
Best approach is to minimize periodontal
ligament damage.
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17. Invasive cervical resorption
Relatively uncommon form of external root
resorption.
Characterized by cervical location and invasive
nature, resorptive process can lead to loss of
tooth structure
Etiology is poorly understood, however,
intracoronal bleaching, orthodontic tooth
movement, trauma ect., are considered as
predisposing factors.
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18. • Classification
Class 1: small invasive resorptive lesion near the
cervical area with shallow penetration in to
dentine
Class 2: well defined invasive resorptive area
that has penetrated close to coronal pulp but
shows no extension in to radicular pulp.
Class 3: deeper invasion of both coronal and
coronal third of radicular dentine by
resorptive process
Class 4: large resorptive focus that has extended
beyond coronal third of root
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19. Osteoclast
*derived from monocyte macrophage
haemopoietic lineage.
*cell responsible for bone resorption
*multinucleated cell containing 4-20 nuclei
*usually found in Howship’s lacunae
*ultrastructure: contain numerous golgi
complexes around each nucleus and
mitochondria and transport vesicles loaded
with lysosomal enzymes
*most characteristic feature is the presence of the
ruffled border and the sealing attachment
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20. *osteoclasts synthesize and secrete tartarate
resistant acid phosphatase and cathepsin
Kinto the extracellular bone resorbing
compartment. In addition, cells also secrete
MMP 9 & 13 which stimulate pre-osteoclast
migration and bone matrix digestion.
*attachment of osteoclast to bone surface is
essential for bone resorption and involves
integrins.
*thereafter, avb3 binding activates
cytoskeletal reorganization within the cell
including cell spreading and polorization.
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21. stem cell
PU1
Osteoclast progenitor
OPG/RANKL Differentiation
macrophage
RANK Fusion
Polarization
Activation
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