This document discusses different types of root resorption, including internal, external, inflammatory, and replacement resorption. It provides details on the definition, causes, mechanisms, diagnostic methods and treatment approaches for each type. The key types discussed are internal infection-related resorption, where necrotic infected pulp tissue triggers the resorption process, and external cervical resorption, which is often linked to trauma, restorations or orthodontic treatment. Diagnosis involves radiographs and vitality testing, while treatment focuses on removing resorptive tissue, root canal therapy if needed, and restoration.

1. BDS(NBI), CIBRD(KASADA), MDSc-Endo(Mal), Cert. In
Oral Implantology (Mal), FADI(USA) FICD(USA)
Senior Lecturer and Specialist Endodontist
Dept of Conservative Dentistry
University of Nairobi
E-Mail: tomdienya@uonbi.ac.ke or tomdienya@yahoo.com

2. DEFINATION
• Resorption : (AAE,1944 ) : Resorption
is a condition associated with either
physiologic or pathologic process resulting
in a loss of dentin, cementum or bone.

4. • Internal resorption : ( Grossman ): Internal
resorption is an idiopathic, slow or fast
progressive resorptive process, occurring in
the dentin of the pulp chamber or root canals
of teeth.
• External resorption : ( Grossman ):
External resorption is a lytic process,
occurring in the cementum or cementum and
dentin of the roots of teeth.

5. Causes of root resorption
A)Physiologic resorption as in decidous teeth
B)Local factors:
• Periapical inflammation
• Dental trauma
• Tumors/cysts
• Excessive mechanical/occlusalforces
• Impacted teeth
• Intracoronal bleaching
• Periodontal procedures
C)Systemicconditions:
• i.Hormonal imbalance
• ii.Paget’sdisease
• iii.Herpeszooster

6. PREREQUISITE FOR
RESORPTION
1. Loss/alteration of the protective
layer(Precementum/Predentin)
2. Inflammation must occur at the
unprotected root surface.

7. MECHANISM OF TOOTH RESORPTION
2 Phases
INJURY STIMULATION

8. INJURY
Concerns the non-mineralized tissues
covering the external(pre-cemental)
surface of the root or the internal(pre-
dentinal) surface of the root.
Injury can be
• Mechanical
• Chemical

9. Stimulation
• Stimulation concerns awide array of
factors:
1)Nature of cells present:
• At the time of injury
• Site of injury
2)Site of tooth involved(Cemental or
dentinal)

10. Sequence Of Events Leading
To Root Resorption
• Crushing and damage to PDL
• Loss of Precementum leading to
denudation of root surface
• Chemotaxisof hard tissue resorbing
cells
• Macrophages & Osteoclasts remove
damaged PDL & Cementum

11. Sequence Of Events
Leading To Root
Resorption
The situation gets further complicated by:
• Eventual exposure of dentinal tubules.
• Contents of the pulp i.e.Ischemic and
sterile or necrotic and infected.
• Presence/Absence of adjacent vital
cementoblasts.

12. • Resorptive process is said to be
aBIMODELPROCESS:
• Dissolution of the Inorganic Crystal Structure
• Degradation of the Organic Structure of
Collagen,Principally Type I

13. • i. Dissolution of the Inorganic Crystal
Structure
• pHlevels below 5,facilitate rapid
dissolution of hydroxyapatite.
• Polarised proton pump along the
ruffled border and the enzyme Carbonic
Anhydrase II play an important role.

14. • ii. Degradation of the Organic Structure
• •Three groups of Protein as enzymes are
involved:
• Collagenases(act at neutralpH)
• Matrix metalloproteinases(act at neutral
pH)
• Cysteine proteinases(act at acidicpH)

15. Diagnosis
Radiographs taken at different horizontal angulations
Vitality testing:
Vital:
• Sub epithelial external root resorption
• Internal root resorption
Non-Vital
• External inflammatory resorption involving an
infected pulp
• Internal root resorption with necrotic coronal pulp
Clinically:
• A pink spot present on the tooth surface

17. Advanced Diagnostic
aids includes:
• Cone Beam Computed
Tomography(CBCT)
• Dental Panoramic Tomography
• True Cephalometry Skull
• Optical Coherence Tomography

19. External Surface Resorption (Repair Related)
Small,superficial resorption cavities in the
cementum and the outer most layers of
the dentin without an inflammatory
reaction in the PDL.
Etiology:
Caused by injury restricted to external root surface.
Resorption can occur due to
• Concussion
• Sub luxation
• Lateral luxation
• Intrusion
• Replantation of avulsed teeth

20. Resorption also occur frequently after
• Orthodontic tooth movement
• Chronic injury affecting PDL
• Traumatic occlusion
• Pressure from developing
cyst/apicalgranuloma/ectopically
eruptingtooth
• •Whentrauma/pressure discontinued–
spontaneous healing occur–
• -typical feature of REPAIR RELATED
RESORPTION

21. PRESSURE
•Due to excessive forces of
Orthodontictoothmovement
Impacted teeth or from tumors or
cysts.
Pressure damages the cementum and
provides the continuous stimulus for
the resorbing cells.

22. Orthodontic movement

23. Endodontic Implication:
• Primarily periodontal injury–endodontic
intervention not indicated
Treatment:
• If trauma/pressure eliminated–almost
100%repair
• If root apex resorbed-excessive mobility
becomes aproblem, if root is shorter than
12mm

24. External Inflammatory Root Resorption
Etiology:
• Resorption presents acombined injury to pulp
and PDL
• Bacteria primarily located in pulp&dentinal
tubules trigger osteoclastic activity on root
surface.
• Resorption can affect all parts of root.
• Diagnosed 2-4 weeks after injury.
• Resorption rapidly progress–total root
resorption within few months.
• Most common after intrusion&replantation.

26. ClinicalFindings:
• Increased mobility
• Dull percussion tone
• Sometimes tooth extruded
• No response to sensibility testing
• Sometimes sinus tract develop

27. Endodontic Implication:
• Resorption–combined periodontal&pulpal
injury
• Require immediate endodontic therapy-to
remove osteoclast promoting
factors(bacterialtoxins)
Treatment:
• Remove/destroy bacteria in root canal&dentinal
tubules.
• Allow healing in entire periradicularregion.
• Bacteria in root canal best destroyed byCa(OH)2. If
Ca(OH)2-used for more than 30days–weakening of
root structure of immatureteeth-causes cervica l
root fracture.

28. Prognosis:
• Dentin lost by resorption cannot be
replaced by new dentin
• Healing occurs–by arresting resorption
process&replacement with either alayer of
new cementum&bone and establishment
of newPDL
• Amount of healing–88%

29. External Trauma Related Replacement
Resorption (Ankylosis)
• Etiology:
SevereTrauma:
• Lateral luxation
• Intrusions
• Replacement of avulsed tooth
• Healing takes place from adjacent healthy
PDL resulting in a normal PDL.
• Healing from bony alveolus–create bony
bridge between socket wall and rootsurface.

31. ClinicalFindings:
• Appear firm in socket
• High metallic sound on percussion
• This can be demonstrated 4-6 weeks after
trauma.
Radiographic Findings:
• Diagnosed radiographically within
2months after injury.
• Clinically identified within one month–high
percussion sound.

33. Endodontic treatment:
• Thorough debridement and preparation of the root canal
system
Sequential use of
• 17%EDTAC(ethylene diaminetetraacetic acid plus
cetavlon)
• 1% sodium hypochlorite and
A final rinse with EDTAC solution
• Most effective regimen resulting in adentine surface devoid of
smear layer.
• •Facilitates the diffusion of
medicaments(Ledermixpaste)through dentine to
theexternalrootsurface

34. •Treatment:
Decoronation-to maintain&augment
alveolar process
•Suitable in children&adolescence when
significant remaining alveolar growth
expected.
Inadolescents–ankylosed tooth fail to
erupt(infraposition)
Younger the age–more pronounced
infraposition
•Procedure:
Removal of tooth crown(slightly below
cervical bone level)leaving remaining part
of root which is then root treated

35. External Cervical Resorption
Etiology:
• Defect in cementoblast layer
• Heithersay et al–studied 259 teeth with
invasive cervical resorption–
• 23%:related to orthodontic treatment
• 15%:acute trauma
• 14%:cervicalrestoration

37. PredisposingFactors:
• •Orthodontic tooth movement
• •Trauma
• •Intracoronal bleaching
• •Surgical procedures
• •Periodontal therapy
• •Other factors:
• Bruxism,intracoronal
restorations,developmental
defects,systemic diseases.

38. ClinicalFindings:
• Expanding lesion-show as a“pinkspot”next
to cervical margin

39. Radiographic Findings:
• Cervical bowl-shaped lesion is the start of
invasive progression of resorption in
coronal&apical direction.
• Pulp canal not invaded in initial phase

40. Treatment:
• Essentially,treatment involves complete
removal of the resorptive tissue and
restoring the resulting defect with aplastic
tooth-coloured restoration.
• Endodontic treatment also be required in
cases in which the ECR lesion has
perforated the root canal.

41. Treatment:
• Heithersay recommended-topica l
application of a90% aqueous solution of
trichloroaceticacid,curettage,and restoration
with glass ionomer cement.
• Trichloroaceticacid causes coagulation
necrosis of the resorptive tissue
• No damage to adjacent periodontal tissues
• It also infiltrates the small channels and
recesses of tooth that otherwise be
unreachable by mechanical instrumentation

43. Internal Resorption
Definition:
• Internal resorption is an unusual form of
tooth resorption that begins centrally within
the tooth,apparently initiated in most cases
by apeculiar inflammation of the pulp
Internal Root Resorption—three types
• Internal surface resorption
• Internal infection related root resorption
• Internal replacement resorption

44. ClinicalFeatures:
• Asymptomatic until it has perforated and
become necrotic
• Detected through routine radiographs
• Pain:lesion perforates and tissue exposed to
oral fluids
• Can be found in all areas of root but most
commonly found in cervical region
• Common in maxillary central incisors
• Usually single tooth but can involve multiple
teeth
• Granulation tissue manifests as a“PinkSpot”

45. Internal Infection Related Root
Resorption
Etiology:
• Coronal to the resorption site in
pulp,necrotic infected tissue is found.
• Resorption site–represents resorbing
granulation tissue interposed between
healthy&diseasedpulp
• Pathogenesis:
• Resorption process–gradually expand–
leading to fracture of root

47. Treatment:
• Endodontic treatment is appropriate
• Require technique that allows
management of resorbed area
• Thermoplastic obturation

48. Treatment:
1)Defect not perforated the root to the periodontal
ligament:
• Obturation with warm gutta percha technique.
2)Defect perforated the root below bone level:
• A hard tissue barrier can be produced with long
term calcium hydroxide treatment,after which
obturation is carried out.
• •Defect perforates coronal to the epithelial
attachment or if an extremely large perforation is
present:
• A surgical approach is required to seal the
perforation.

49. Treatment(Apical):
• Extend instrumentation only to the position
of the resorption.
• With the removal of micro-organisms
followed by root canal filling,hard tissue
repair will occur in the resorbed apical
region.
• Treatment to the position of the resorption
help in achieving biological repair of the
resorbed apex.

50. Treatment(Intraradicular):
• Preparation of the canal to the apical
foramen.
• Particular emphasis on irrigation and
ultrasonication(resorbed area is cleansed
thoroughly).
• Thermoplastic obturation of canal.