1. Pulpal
Reactions
to Caries and
Dental
Procedures

2. Topic outline:
• Pulpal Reactions to Caries.
• Pulpal Reactions to Local Anesthetics.
• Pulpal Reactions to Restorative Procedures.
• Pulpal Reactions to Restorative Materials.
• Pulpal Reactions to Laser Procedures.
• Pulpal Reactions to Cavity Preparation Using Air
Abrasion Techniques.
• Pulpal Reactions to Vital Bleaching Techniques.
• Pulpal Reactions to Periodontal Procedures.
• Pulpal Reactions to Orthodontic Surgery.
• Pulpal Reactions to Implant Placement And
Function.

3. I. Pulpal Reaction to Caries
Protective Pulpal Reactions includes;
1)Decrease in dentin permeability.
2)Tertiary dentin formation.
3)Inflammatory and immune reactions.

4. I. Pulpal Reaction to Caries
Protective Pulpal Reactions includes;
1)Decrease in dentin permeability:
It is the first & fastest defense to caries and is
called Dentin Sclerosis.
Increase the deposition of mineral crystals in
intratubular dentin → narrowing the dentinal
tubules → decreasing dentin permeability

5. I. Pulpal Reaction to Caries
Protective Pulpal Reactions includes;
2)Tertiary dentin formation:
It is not the most effective pulpally mediated
defense.
Mechanism; acidic byproducts of the carious
process → degrade the dentin matrix →
liberate bioactive molecules sequestered
during dentinogenesis → reassume their role in
dentin formation.

6. I. Pulpal Reaction to Caries
Protective Pulpal Reactions includes;
2)Tertiary dentin formation:
The resultant dentin character is highly
dependent on the stimulus.
In Mild Carious Lesion, odontoblasts are
activate to elaborate the organic matrix of
dentin (reactionary dentin), which is similar in
morphology to physiologic dentin and may
only be apparent due to a change in the
direction of the new dentinal tubules.

7. I. Pulpal Reaction to Caries
Protective Pulpal Reactions includes;
2)Tertiary dentin formation:
The resultant dentin character is highly
dependent on the stimulus.
In Aggressive Carious Lesion, repopulation of
the disrupted odontoblast layer with
differentiating progenitors, forming reparative
dentin, its morphology can range from
organized tubular dentin to more disorganized
irregular fibrodentin.

8. I. Pulpal Reaction to Caries
Three basic reactions tend to protect the pulp:
3)Inflammatory and immune reactions:
In the advancing infection front of the carious
lesion, multiple extrinsic and intrinsic factors
that stimulate inflammatory reactions,
provides cellular and humoral challenges to
invading pathogens.
N.B: The buffering capacity of dentin fluid
likely attenuates the pH before it can directly
effect a deleterious response, except when
the remaining dentin thickness is minimal

9. I. Pulpal Reaction to Caries
Three basic reactions tend to protect the pulp:
3)Inflammatory and immune reactions:
The early inflammatory response can be seen
beneath noncavitated lesions and
noncoalesced pits and fissures.
It is characterized by the focal accumulation
of chronic inflammatory cells.

10. I. Pulpal Reaction to Caries
Three basic reactions tend to protect the pulp:
3)Inflammatory and immune reactions:
It is mediated;
Initially by odontoblasts; the most peripheral
cell in the pulp, and encounter foreign
antigens first.
& later by dendritic cells, which are
responsible for antigen presentation and
stimulation of T lymphocytes.

11. I. Pulpal Reaction to Caries
Three basic reactions tend to protect the pulp:
3)Inflammatory and immune reactions:
Two distinct populations of dendritic cells:
•CD11c+ found in the pulp/dentin border and
subjacent to pits and fissures.
•F4/80+ concentrated in the perivascular
spaces in the subodontoblastic zone and inner
pulp.

12. I. Pulpal Reaction to Caries
Three basic reactions tend to protect the pulp:
3)Inflammatory and immune reactions:
Odontoblasts play a role in the humoral
immune response to caries. Immunoglobulin
(Ig)G, IgM, and IgA have been localized in the
cytoplasm and cell processes of odontoblasts
in human carious dentin, suggesting that these
cells actively transport antibodies to the
infection front.

13. I. Pulpal Reaction to Caries
Three basic reactions tend to protect the pulp:
3)Inflammatory and immune reactions:
N.B: In the most advanced phase of carious
destruction, the immune response is
accompanied by immuno-pathologic
destruction of pulpal tissue.

14. Dentin Hypersensitivity and Its
Management
Definition:
It is represented as a special chronic, short,
sharp pulpal pain arises from exposed dentin
in response to different stimuli.
Dentin hypersensitivity may be related to:
•Excessive abrasion during tooth brushing.
•Periodontal disease.
•Erosion from dietary or gastric acids
•Performance of scaling and root planning.

15. Dentin Hypersensitivity and Its
Management
Mechanism:
the lack of protective layer allows the
hydrodynamic movement of fluid in patent
dentinal tubules that are present in areas of
hypersensitivity.
Treatment:
The application of neural modulating agents
or tubule blocking agents or materials that
bond to the tooth surface.

16. Dentin Hypersensitivity and Its
Management

17. Dentin Hypersensitivity and Its
Management
N.B:
•A concern has been raised that the acidic
pH during etching may cause dissolution of
the oxalate crystals, thus interfering with the
effectiveness of the material.
•In the long term, the development of smear
layer, such as from tooth brushing, dentin
sclerosis, reactionary dentin, and the
blockage of tubules with large endogenous
macromolecules are all thought to reduce the
problem.

18. II. Pulpal Reactions to Local
Anesthetics:
Vasoconstrictors:
•such as: lidocaine and 1:100,000 or 1:80,000
epinephrine.
•Benefits: enhance the duration of anesthesia.
•Side effect: reduce the blood flow of the
pulp.
N.B: The supplemental anesthetic techniques
cause more severe reduction or even transient
cessation of pulpal blood flow.

19. II. Pulpal Reactions to Local
Anesthetics:
N.B: The effect of intrapulpal anesthesia on the
pulp is not considered, since it is used during
root canal therapy when other anesthetic
administrations are insufficient.
•However, during pulpotomy in tooth with
immature apex, no difference was detected
on follow-up of over 24 weeks after
administration of intrapulpal anesthesia that
contain epinephrine.

20. III. Pulpal Reactions to Restorative
Procedures:
One key requirement of a successful
restorative procedure maintaining the pulp
vitality is to cause minimal additional irritation
of the pulp so as not to interfere with normal
pulpal healing.
Pulp reaction to restorative procedure is
controlled by:
1.Degree of Pretreatment Pulp Inflammation.
2.Degree of Physical Irritation
3.Biologic and Chemical Irritation:
4.Proximity of Restorative Procedures to Pulp

21. III. Pulpal Reactions to Restorative
Procedures:
1) Degree of Pretreatment Pulp Inflammation:
In the absence of severe spontaneous symptoms or
pulp exposure, the clinician cannot accurately
determine the degree of preoperative pulpal
inflammation. Thus, every effort should be made to
minimize added irritation during restorative
procedures.
In cases of aseptic mechanical exposures, exposure
longer than 24 hours associated with the formation
of a bacterial biofilm that is difficult for the pulpal
immune responses to eliminate.

22. III. Pulpal Reactions to Restorative
Procedures:
2) Degree of Procedure Physical Irritation:
• Heat:
Any restorative procedures leads to increase in pulpal
temperatures;
In case of 10° C rise → In case of 20° C rise →
irreversible pulp pathosis pulp abscess formation
Gradual controlled heat application over a large
area may not cause adverse reactions in the pulp.
If the cavity floor ≤ 0.5 mm from the pulp, areas of
coagulation necrosis could be detected.

23. III. Pulpal Reactions to Restorative
Procedures:
2) Degree of Procedure Physical Irritation:
• Desiccation:
It is the aspiration of odontoblastic nuclei into dentinal
tubules.
It is transient, within 7 to 30 days there is autolysis of the
aspirated cells and formation of reactionary
dentin.
The pulp in cases with aspirated odontoblasts,
following desiccation for 1 minute, was not
sensitive to clinical scraping with an explorer.

24. III. Pulpal Reactions to Restorative
Procedures:
3) Biologic and Chemical Irritation:
The sources of microbial irritaion:
 cariogenic microorganisms remaining on
cavity floor.
 contamination with salivary
microorganisms.
 contamination with bacteria from water
lines.
prompting the use of cavity disinfection
(chemicals irritation), and so the most
common irritant is etching agents.

25. III. Pulpal Reactions to Restorative
Procedures:
N.B:
Once dentin is exposed, there is constant
outward flow of dentinal fluid that minimizes
the inward flow of any noxious agents. This
may aid in the reduction of irritation from
residual microbial factors in dentinal tubules.

26. III. Pulpal Reactions to Restorative
Procedures:
4) Proximity of Restorative Procedures to
Dental Pulp & Surface Area of Dentin
Exposed:
= Depth and/or Width of a Tooth Preparation:
There is an increasingly severe pulpal reaction,
with a greater likelihood of the pulp
undergoing irreversible pathosis, as the
carious lesion progresses towards the pulp,
particularly when the remaining dentin
thickness (RDT) is less than 0.5 mm.

27. III. Pulpal Reactions to Restorative
Procedures:
4) Proximity of Restorative Procedures to Dental Pulp
& Surface Area of Dentin Exposed:
= Depth and/or Width of a Tooth Preparation:
N.B:
With the passage of time following cavity preparation,
there is reduction in the permeability of RDT, due
to rapid deposition of reactionary dentin, the
migration of large proteins into the tubules, and/or
the diminution of tubule diameter as dentin
becomes more sclerotic.

28. III. Pulpal Reactions to Restorative
Procedures:
5) Permeability of remaining dentin & related
odontoblastic :
The dentin is not uniformly permeable, and
that permeability depends on factors such
as;
a) The location within the same tooth the
pulp.
b) The age of the patient.
c) The presence of pathologic conditions.

29. III. Pulpal Reactions to Restorative
Procedures:
5) Permeability of remaining dentin and
related odontoblastic :
a) The location within the same tooth:
The tubular diameter increases from about 0.6
to 0.8 μm close to the DEJ to about 3 μm at
the pulp. Given that bacterial cells are
about 0.5 to 1 μm in diameter, it is evident
that in deep cavity preparations,
particularly when total-etch procedures are
employed, bacteria can migrate through
the remaining dentin into the pulp.

30. III. Pulpal Reactions to Restorative
Procedures:
5) Permeability of remaining dentin and
related odontoblastic :
b) The age of the patient,:
The width of peritubular dentin increases with
age, causing reduction in tubular lumen or
sclerosis.

31. III. Pulpal Reactions to Restorative
Procedures:
5) Permeability of Remaining Dentin and
Related Odontoblastic :
c) The presence of pathologic conditions such
as dental caries.
• In superficial dentin, formation of caries
crystals within the tubules of inner
undemineralized dentin → decrease in
permeability in dentin.

32. III. Pulpal Reactions to Restorative
Procedures:
5) Permeability of Remaining Dentin and
Related Odontoblastic :
c) The presence of pathologic conditions such
as dental caries.
• In superficial dentin,

33. III. Pulpal Reactions to Restorative
Procedures:
5) Permeability of Remaining Dentin and
Related Odontoblastic :
c) The presence of pathologic conditions such
as dental caries.
• In superficial dentin, formation of caries
crystals within the tubules of inner
undemineralized dentin → decrease in
permeability in dentin.
• Related odontoblasts, it was shown that
irritation from cavity preparation increased
the odontoblastic permeability only at the
site of the cavity preparation.

34. III. Pulpal Reactions to Restorative
Procedures:
5) Permeability of Remaining Dentin and
Related Odontoblastic :
N.B:
In addition to the physical barrier to
permeability and the production of
reactionary or reparative dentin, the
odontoblastic layer may in fact contribute
to the host response of the dental pulp by
expressing important inflammatory
mediators or recognize bacteria through
toll-like receptor

35. III. Pulpal Reactions to Restorative
Procedures:
6) Patient Age:
• Resting pulpal blood flow (PBF),
• Response to cold application, decrease
with age.
• Reduction in pulpal neuropeptides.

36. IV. Pulpal Reactions to Restorative
Materials:
1)Direct Effect 2)Indirect Effect
1) Direct effect of restorative materials:
• Certain cytotoxic components of resin
monomers (Triethylene glycol
dimethacrylate & 2-hydroxyethyl
methacrylate).
• Some of the components of resin
restorations are released at cytotoxic levels
after polymerization is completed.

37. IV. Pulpal Reactions to Restorative
Materials:
These chemicals have either:
A short lived and in the absence of bacteria,
is reversible
Or
Irreversible prolonged cytotoxicity,
stimulation of hypersensitivity reactions, or
impairment of the host immune response to
bacteria.
N.B:
•Subtoxic concentrations of certain agents
are capable of eliciting allergic reactions in
humans.

38. IV. Pulpal Reactions to Restorative
Materials:
1)Direct Effect 2)Indirect Effect
2) Indirect effect of restorative materials:
The technique sensitivity of certain materials
predisposes them to faulty bonds to tooth
structure that can translate to dentin
hypersensitivity, recurrent disease, and
pulpal inflammation or necrosis.

39. IV. Pulpal Reactions to Restorative
Materials:
During the etching process:
The more highly mineralized peritubular dentin is
preferentially dissolved, leaving free collagen fibrils
and opening lateral tubular branches. Applied resin
infiltrates the exposed collagen mesh, creating a layer
5 to 10 μm thick referred to as the hybrid layer.
•If the preparation is too dry, the collagen fibrils
collapse.
N.B:
The optimal degree of hydration of the preparation
surface can vary from material to material.

40. IV. Pulpal Reactions to Restorative
Materials:
N.B:
•It is recommend to rehydrate the fragment
segment of the tooth prior to bonding, to
increase the mechanical and the microbial
seal.
•This is particularly important with a
complicated crown fracture where the pulpal
protection by intact dentin is absent

41. IV. Pulpal Reactions to Restorative
Materials:
Pulpal irritation is not considered a negative
sequela all the time, the irritant potential of
certain restorative materials has a useful
motivated effect on odontoblasts in case of
direct & indirect pulp capping.
The outcome of such treatments depends on:
•The biocompatibility of used medicaments.
•The ability to seal the cavity.
•A combination of the above.
•Ability to control hemorrhage at the
exposure site.

42. IV. Pulpal Reactions to Restorative
Materials:
For example:
Calcium Hydroxide
Zinc Oxide Eugenol
Mineral Trioxide Aggregate
Hemostatic Agents
2% chlorhexidine or 5.25% sodium
hypochlorite

43. IV. Pulpal Reactions to Restorative
Materials:
Calcium hydroxide
In direct pulp capping: It induces the
formation of dentinal bridge
•Aqueous suspensions preparation: causes
superficial necrosis of pulpal tissue followed by
tissue displaying low-grade inflammation.
Within 30 days, the tissue subjacent to the
necrotic zone has reorganized and resumed
normal architecture.
•Hard-setting preparation: is effective in
eliciting dentinal bridge formation with a
much smaller to nonexistent necrotic zone.

44. IV. Pulpal Reactions to Restorative
Materials:
Calcium hydroxide:
In indirect pulp capping:
•The Application of calcium hydroxide to
intact dentin appears to induce sclerosis by
promoting crystal precipitation within the
tubules, accompanied by reductions in
permeability.
•The irritation potential is dependent on the
remaining dentin thickness and permeability.

45. IV. Pulpal Reactions to Restorative
Materials:
Materials containing zinc oxide and eugenol:
ZOE is used for;
•Anesthetic properties:
It has been shown to block transmission of
action potentials in nerve fibers & suppress
nerve excitability in the pulp when applied to
deep excavations.
•Antiseptic properties:
It inhibits bacterial growth on cavity walls.
•Sealing ability:
It has good adaptation to dentin.

46. IV. Pulpal Reactions to Restorative
Materials:
Direct Pulp Caping with Mineral Trioxide Aggregate
(MTA):
Indication: in pulps with traumatic or carious exposure,
for allowing the formation of a reparative dentin
bridge and maintain continued pulp vitality.
•At 1st week, no sign of necrosis close to the exposure
site, and odontoblast-like cells are observed at the
periphery with the deposition of calcified bridge.
•At 2nd weeks, complete calcified bridge formation just
below the exposure site.

47. IV. Pulpal Reactions to Restorative
Materials:
Direct Pulp Caping with Mineral Trioxide
Aggregate (MTA):
Success was determined:
•Radiographically.
•Disappearance of subjective symptoms.
•Normal pulp testing with cold.
•continued root formation on immature teeth.
Success depends on the prevention of
bacterial ingress by the placement of a well-
sealed restoration must also be provided.

48. IV. Pulpal Reactions to Restorative
Materials:
Use of Hemostatic Agents and Disinfectants on
Direct Pulp Exposures:
The mechanical exposure of a healthy pulp
created during cavity preparation could be
disinfected with either 2% chlorhexidine or
5.25% sodium hypochlorite.

49. V. Pulpal Reactions to Laser
Procedures:
• Laser use on soft / hard tissues has potential
benefits of efficiency, reduced sensitivity,
disinfection, and precision.
• There are several different types of laser
available that depend on the wavelength,
active medium, emission mode, delivery
system, power output, and duration of
application.

50. V. Pulpal Reactions to Laser
Procedures:
The main types available in dentistry today are:
•The CO2 laser (10,600 nm).
•Er:YAG laser (2940 nm), has a high affinity for water
and hydroxyapatite.
•Ho:YAG laser (2120 nm), has high affinity to water
but not to tooth structure.
•Nd:YAG laser (1064 nm), has high affinity for water
and pigmented tissues and offers good hemostasis.
•HeNe laser (632 nm). laser Doppler
•GaAlAs laser (720-904 nm). flowmetry and in
treating dentin
hypersensitivity.

51. VI. Pulpal Reactions to Cavity
Preparation Using Air Abrasion
Techniques:
Effect on pulp:
During cavity After restoration:
preparation:
Higher pressures & It produces
smaller particles (160 psi microleakage in a
- 25 μm) has less pulpal equivalent degree to
effects than the high- high-speed bur
speed and lower preparations, (Why?)
pressures &larger Because of the lack of
particles (80 psi - 50 μm) tactile control.
treated teeth.

52. VII. Pulpal Reactions to Vital
Bleaching Techniques:
Using of strong oxidizing agents
(such as: carbamide peroxide & hydrogen peroxide)
pulpal irritation
Minor inflammation up to Sever inflammation
2 weeks → reversible → irreversible
pulpitis, prevented by pulpitis → pulpal
treating the teeth with necrosis.
fluorides & by correcting
defective restorative.

53. VII. Pulpal Reactions to Vital
Bleaching Techniques:
Clinical symptoms are likely to be due to
increases in neuropeptides in the pulp.
N.B: A recent studies showed that 10%
carbamide peroxide in a custom tray for 6
weeks was safe for the pulp health, while light-
& laser-activated bleaching systems, due to
increase neuropeptides expression in the pulp
to significant levels.

54. VIII. Pulpal Reactions to Periodontal
Procedures:
It is much more common for pulp necrosis or
failed healing of periradicular lesions to present
clinically with signs of periodontal disease than for
periodontal disease to cause pulpal pathosis.
1ry pulpal, 2ry periodontal 1ry periodontal , 2ry pulpal
pathosis:. pathosis:
is particularly evident with is rare to occur. But
pulp chamber / coronal third periodontal scaling and root
perforation, vertical root planning results in dentin
fractures or congenital tooth hypersensitivity.
defects.

55. VIII.Pulpal Reactions to Periodontal
Procedures:
(Why?)
It is more likely for microbial irritants to move
outward from a vital / necrotic pulp to cause
periodontal breakdown than for them to
move inward from a periodontal pocket to a
vital pulp causing irreversible pathosis.

56. VIII.Pulpal Reactions to Periodontal
Procedures:
(How?)
The outward dentinal fluid flow in teeth with
vital pulp contributes to the resistance to
ingress of bacteria in sufficient amounts to
cause a clinically significant disease process.
Once the pulp degenerates, dentinal fluid
flow no longer exists.

57. IX. Pulpal Reactions to Orthodontic
Surgery:
Osteotomy of the jaw
Disruption in the blood supply
• Postoperative • Inflammation
manifestations common and/or
with traumatic injuries necrosis.

58. IX. Pulpal Reactions to Orthodontic
Surgery:
N.B: Studies have shown that if a safe distance
of 5 to 10 mm is maintained between the site
of the surgery and the teeth, minimal
disruption occurs. In most cases, the blood
flow is regained within months of the surgery.

59. IX. Pulpal Reactions to Orthodontic
Surgery:
N.B: Studies have shown that if a safe distance
of 5 to 10 mm is maintained between the site
of the surgery and the teeth, minimal
disruption occurs.
N.B: In most cases, the blood flow is regained
within months of the surgery.

60. X. Pulpal Reactions to Implant
Placement and Function:
• The placement of implants requires
multifaceted preoperative radiographic
techniques.
(Why?)
The lack of attention to:
(1)3-dimensional anatomy of the site
of implant placement.
(2) the orientation of neighboring teeth.
 perforating the root and devitalizing the
pulp.

61. X. Pulpal Reactions to Implant
Placement and Function:
It is usually recommended to place the
implants at a site free of periradicular lesion.
(Why?)
microbial irritants may interfere with
osseointegration.
•Some studies claimed that teeth with
periradicular lesions may reduce the success
of neighboring implants, even if adequate
endodontic treatment is performed.

62. X. Pulpal Reactions to Implant
Placement and Function:
However, recent data suggest that immediate
implant placement in sites that have been
adequately débrided is successful.
Furthermore, implants that are not mobile but
have apical periimplant lesions have been
successfully treated with local débridement
and “implant-apex resection” procedures.

63. Regenerative Potential of the Dental
Pulp:
Recent studies and case reports suggest that
the dental pulp has great regenerative
potential, particularly in the immature
permanent tooth.
(How?)
Stem cells from the apical papilla (SCAP) of
immature teeth have likewise been identified
and have been shown to develop into
dentinogenic cells, given the proper
stimulation.