1. Biology And Clinical Rationale
For Root Canal Therapy
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2. 1/12/2009 Endo 2 2

3. Functions of the pulp
1. Induction(Odonogenesis and Amelogenesis)
2. Formation of dentine (Primary, Secondary-reactionary
and Tertiary-reparative).
3. Maintenance of dentine (fluid environment).
4. Defence mechanism by inflammatory and
immunological
5. Sensation from dentine and enamel (pain, warning).
6. Age changes (peritibular dentine, more solid tooth)
(Walton and torabinjad – 1996).
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4. Induction (Odonogenesis and Amelogenesis)
Dental pulp 25mm3
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5. Formation of dentine (coronal and radicular).
Predentine thickness 15µ
Primary dentine during development 4µ/day
Regular Secondary dentine after develop 0.8µ/day
Irregular Secondary dentine due to stimuli 3µ/day
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6. Formation of dentine (coronal and radicular).
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7. Formation of dentine (coronal and radicular).
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8. Maintenance of Dentine (fluid environment).
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9. Maintenance of Dentine (fluid environment).
Pulpal end D-E Junction
Tubules 65000 /mm2 15000/mm2
Diameter 3µ 1µ
Surface area 45% 1%
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10. Maintenance Dentine (fluid environment).
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11. Defence mechanism (IIry dentine, reparative dentine, fluid flow).
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12. Sensation (pain, warning).
1 axon innervate 100 dentinal tubules and penetrate up to 100-200µ
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13. Age changes (peritibular dentine, more solid tooth).
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14. Theories of dentine hypersensitivity
• Classic theory – (Direct innervations)
A-δ fibres -sharp, localized pain (drilling, probing, air drying,
application of hyper osmotic fluids heating and cooling the
dentine electrical pulp testing)
C- fibres -dull less localized pain (thermal, mechanical and
chemical stimuli)
A-β myelinated fibres-non-noxious mechanical stimulation
(mastication and loading of teeth)
• Odontoblast as receptors – (neural crest)
• Hydrodynamic theory
Rapid movement of fluid of in the dentinal tubules
cause mechanical distortion of tissue
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15. Sensation (pain, warning).
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16. Differential diagnosis of acute pains
Condition Nature Triggers Duration
Odontalgia Stabbing, throbbing, Hot, Tooth Hours-days
cold and non-episodic. percussion
Trigeminal Lancination, electrical, Light touch on Seconds
neuralgia episodic trigger zone
Cluster Severe ache, retro-obital Sleep, alcohol 30-45 min
headache component, episodic
Acute otitis Severe ache, throbbing,. Lowering head, Hours-days media
deep to ear, nonepisodic barometric pressure
Bacterial Severe ache, throbbing. Lowering head, Hours-days sinusitis
in maxillary posterior tooth percussion
teeth, nonepisodic
Cardiogenic Short-lived ache left Exertion Minute
posterior mandible
Sialolithiasis Sharp, drawing, salivary Eating, induced Low ache
sharp swelling, episodic salivation when triggered
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17. Differential diagnosis of chronic pains
Condition Nature Triggers Duration
Odontalgia Dull ache, Hot, cold, tooth Days-weeks
percussion
TMJ pain Dull ache, sharp episodic Opening chewing Weeks-years
Myalgia Dull ache, degree varies Stress, clenching Weeks-years
Atypical facial P Dull ache severe episodes Spontaneous Weeks-years
Phantom tooth P Dull ache severe episodes Spontaneous Weeks-years
Allergic Dull ache in maxillary Lowering head Weeks-month
sinusitis posterior teeth seasonal
Causalgia Burning Post trauma, Weeks-years
post surgical
Post herpitic Deep boring ache with Spontaneous Weeks-years
neuralgia burning after shingles
Cancer associated Variable,motor difficult, Spontaneous Days-months
facial pain paresthesia
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18. Aetiology of pulp & periapical disease
Bacteria 1-Coronal ingress(caries) 2-Radicular ingress (PDD)
Trauma 1-Accident 2-Physiological
Chemical 1-Filling material 2-Erosion
Iatrogenic 1-Cavity preparation (type of bur, speed, duration, nature of bur
contact, cutting technique, amount vibration and cooling)
2-Restoration 3-Surgical trauma
4-Prosthetic treatment 5-Radiation
6-Orthodontic movement 7-Electric
8-Periodontal treatment 9-General Anaesthesia
Others 1-Ageing 2-Internal resorption
3-External resorption
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19. Bacteria
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20. Bacteria
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21. Chemical-Filling material
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22. Cavity Preparation
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23. Restoration
Post operative complications of restorations are, Marginal staining, dentine hyper
Sensitivity,, corrosion and degradation, secondary caries, pulp inflammation and
death (Gulabivala-2004).
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24. Restoration
If the thickness of dentine is <5mm
Ca(OH)2 sub lining and ZnO/E dressing
should be placed. Most effective material
preventing microbial leakage
LCC and GIC cause more damage to
odontoblasts (Gulabivala-2004).
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25. Responses To Injury
Depend on,
• The state of the pulp,
• Previous history of irritants and repair,
• The nature of the stimulus,
• Duration of the irritation,
• Any treatment provided.
Mild injury –
• Odontoblast die,
• Acute inflammation in sub odontoblast layer,
• Resolution
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26. Major Acute Injury
• Some pulp tissue die,
• Acute inflammation in adjacent tissue,
• Walling off affected area (fibrosis),
• Pulpal abscess; pressure, pain,
• Repair – depend on tissue capacity to repair
and toxicity of necrosis (repair by fibrosis or
reparative dentine),
• If no repair, spread of necrosis to whole pulp.
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27. Why Does The Pulp Die?
A- No drainage within the pulp, (fluid can only
move through rest of pulp),
B- Limited access for repair (from apical
direction only),
C - Pulp is surrounded in three dimensions
(by hard tissue),
D - Stimulus is concentrated in the pulp
(diffusion through tubules from large area
and concentrated on small tissue),
E- Limitations of dental materials available for
treatment.
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28. Classification Of Pulp & Periapical Disease
a) Clinical normal pulp,
b) Reversible pulpitis 1-Acute 2-Chronic
c)
) Irreversible pulpitis 1-Acute 2-Chronic 3-Necrobiosis
d) Pulp necrosis 1-With & 2-Without infection
e) Degenerative changes 1-Atrophy
2-Hyperplasia (pulp polyp)
3-Calcification (partial, total)
4-Internal resorption.
f) Previous RCT 1-Satisfactory (with & without infection)
2-Unsatisfactory (with &without infection)
g) Perio-endo lesion 1-Endodontic origin
2-Periodontc origin
3-Combine P-E (do&not communicate)
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29. Reversible Pulpitis
• Short duration pain
• After stimulation remove pain relieve
• Tooth no tender to percussion
• Difficult to localized the pain
• Exaggerated respond to vitality test
• Periapical area is normal in x-rays
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30. Recent Restoration
• High filling or points
• Micro leakage
• Micro exposure
• Thermal or mechanical injury to pulp
• Inadequate lining under metalic restoration
• Chemical irritation from lining or filling material
• Galvanic current
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31. Irreversible Pulpitis
• Early stages spontaneous pain last few
second to hours, radiate and difficult
locate the tooth
• Latter stage hot thing pain, cold relieve
the pain patent able to locate the tooth
and tender to percussion
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32. Dynamics of Pulpal Responses
Reversible Irreversible
Bacteria Low-grade Resistance Chronic
inflammation Untreated pulpitis
Virulence
Treated
Acute
Resolution pulpitis
mild
Major Partial Total
necrosis necrosis
Short-term Acute
insult inflammation
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33. Indicators Of Pulpitis
Indicator Irreversible Reversible
pulpitis pulpitis
Sensitivity to thermal stimulation Yes Yes
Respond to thermal stimulation
a) Lingering Yes No
b) Short No Yes
Previous history of pain Yes No
Intensity of pain a) Severe Yes No
b) Mild No Yes
Nature of pain – Spontaneous Yes No
Tenderness to percussion Not always Rarely
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34. Peri-apical Defence Mechanism
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35. Classification Of Periapical Periodontal Disease
a) Clinical normal periodontal tissue,
b) Apical periodontitis
1-Acute
2-Chronic - Granuloma
Radicular cyst - Apical true cyst
- Apical pocket cys
3-Condensing osteitis
a) Periapical abscess1- Acute 2-Chronic
b) Facial cellulitis
c) External root resorption
1- Surface 2- Inflammatory
3- Replacement 4- Invasive
5- Pressure 6- Orthodontic
7- Physiologic
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36. Dynamics Of Periapical Inflammation
Draining
Sinus
Bacterial Resistance Chronic
Insult apical Cyst
periodontitis
Virulence
Systemic
Short-term Acute apical illness
insult periodontitis
Facial
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37. General Order Of Treatment
1. Pain relief
2. Remove infection
3. Caries control
4. Periodontics
5. Endodontics
6. Orthodontics / Surgery
7. Prosthodontics
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38. Aims Of Endodontic Treatment
• Biologic aims
a) To remove all the debris support to bacterial
growth
b) To destroy all micro-organisms from the root
canal
• Mechanical aims
c) Prepare root canal space for three
dimensional filling
d) To obturate prepared canal in order to
completely seal from both apical (at the
cemento-enamel junction) and coronal seal
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39. • Root treated with a poor obturation but
good coronal restoration had prognosis
than good obturation and poor coronal
restoration (Ray and Trope-1995).
• Whatever the obturation system used if
the canal system has not been adequately
cleaned healing may not occur(Carrotte-
2004)
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