pulp protecton.ppt

1. GOOD MORNING

2. PULP PROTECTION

3. CONTENTS
• PULP
• STRUCTURAL FEATURES
• FUNCTIONS OF PULP
• PULPAL PATHOSIS
• PULP REACTION TO CARIES
• PULPAL REACTION TO RESTORATIVE
PROCEDURES & MATERIALS
• PULP PROTECTION

4. PULP
Loose Connective tissue uniquely
situated within the rigid encasement
of
the mineralized dentin
Total volume is 0.38cc;mean volume of
single adult human pulp is 0.02cc

5. Structural features:
• Central region /pulp proper of both
coronal and radicular pulp contains
large nerve trunks and blood vessels
• Peripherally the zones are
• 1.odontoblastic zone
• 2.cell free zone (weil’s zone)
• 3.cell rich zone

6. ODONTOBLASTS

7. RELATIONSHIP OF PULP TO DENTIN

8. Blood supply:
• Highly vascularised tissue
• Blood supply through inferior &
superior alveolar artery
• Blood pressure ranges from 5 to 15
mm of hg
• Respiratory rate of pulpal cells is
3.2ml o2/min/100gms

9. Nerve supply:
• Innervation include
• Afferent nuerons
• Autonomic innervation
• Two types of sensory nerve fibers:
• Myelinated
• Unmyelinated

10. PULP IS UNIQUE
because:
• Pulp is enclosed in a rigid mineralized
dentin
• Microcirculatory system
• Regeneration and repair diminishes
with age
• Sensitive to thermal stimulus
• Ability of formation of dentin
throughout life

11. Pulpal pathosis
• Caries
• Restorative procedures

12. PULPAL REACTION TO
CARIES
• Decrease in dentin
permeability
• Tertiary dentin
formation
• Inflammatory and
immune reactions

13. Pulpal reaction to caries
• Degree of inflammation depends on
1.the nearness of caries to the pulp
2.permeability of underlying dentinal
tubules
The most common response being
dentinal sclerosis

15. Relationship of depth of
the preparation to
reparative dentin
formation
• As the cavity depth increases the
rate of reparative dentin formation
decreases.
• Structure becomes more irregular
• Quality is poorer

16. CAVITY AND CROWN PREPARATION
• Thermal injury
• Vibratory phenomena
• Desiccation of dentin IATRAL
• Cementing forces CAUSES
• Pulp Exposure
• Smear layer
• Acid etching
• Agents for cavity cleansing and Drying

17. THERMAL INJURY
• Frictional heat
• Speed of rotation, size and shape of the cutting
instrument, length of time in contact with dentin,
• Amount of pressure exerted on handpiece
• Temp raised above ambient temp (8-10 degrees);
cell death occurs
• Pink or purple color (DENTINAL BLUSHING) due to vascular
stasis of subodontoblastic capillary plexus blood flow which
rupture and release RBC’s
• Safest way to prepare tooth structure is to use ultra high
speed rotation,with efficient water cooling system and
intermittent cutting

18. SPEED OF ROTATION
• Speeds from 150000 to 250000 with
water coolant is safe
• No safe speed without water coolant
• Water coolant is more advantageous
than air spray
• A 5 - 7 degree temperature elevation
increases the capillary permeability

19. DENTIN BURN
• Occurs following the use of high
speed instruments
• Charred dentinal tubules are more
susceptible to subsequent decay

20. SIZE OF THE BURS
AND WHEELS
Larger sizes produced greater pulpal
damage owing to the increased heat
generation
Peripheral speed of larger disks is
higher than that of smaller disks

21. VIBRATORY
PHENOMENA
• Particularly when cutting speed is
reduced
• “Shock-wave” phenomena
• Mechanical vibration responsible for
protein denaturation
• Disruption of odontoblastic cell layer
or death of odontoblastic cell (s)

22. DESICCATION OF
HEAT
• Drying of cut dentin with a jet of air
produces a rapid outward movement
of fluid through the dentinal tubules
• Not only does this stimulate sensory
nerve fibers (pain), this fluid
movement may “draw” odontoblasts
up into the tubules resulting in cell
death

23. Retentive pins
• Friction locked pins produce micro
fractures extending into the pulp
• Pulpal stress is maximal when self
threaded pins are inserted
perpendicular to the pulp
• Atleast 1mm of RDT from the pulp
elicits minimal pulpal response

24. CROWN PREPARATION
• Pulp Necrosis with full crown prep =
13.3%
• Pulp Necrosis with partial veneer
prep = 5.1%
• • Pulp Necrosis with core build-ups =
17.7%

25. REBOUND RESPONSE
• By bernier and knapp
• Related to high energy released by
ultrasonic cutting/by ultra high
speeds
• When cavity is prepared on one side
of the tooth, the reactions occur on
the opposite side

26. SMEAR LAYER
• Layer of organic and
inorganic debris
• To remove or not?
• Removal may
increase dentin
permeability
• Bacteria in smear
layer may be a
problem

27. CEMENTING FORCES
• Strong hydraulic forces can force
the liquid towards the pulp which may
cause inflammatory changes in the
pulp
• To prevent this dentin should be
covered with liner or base.

28. ACID ETCHING
• Citric acid and Phosphoric acid
widens the openings of the dentinal
tubules with the result that the
changes of bacterial penetration
into the dentinal tubules and
reaching the pulp are increased

29. AGENTS FOR CAVITY
CLEANSING AND DRYING
Used to remove smear layer and
decrease the micro organisms on the
dentinal surface
Most of them contain lipid solvents such
as acetone and ether
Cavities should be dried with cotton
pellets and short blasts of air rather
harsh chemicals

30. Effect of heat from
bleaching agents
• Cohn and robertson found a lack
of/mild inflammatory responses in
the pulps of tetracycline stained
teeth bleached with 35%H2O2

31. RESTORATIVE MATERIALS
• Chemical toxicity
• Acidity
• Absorption of water during setting
• Poor marginal adaptation resulting in
bacterial contamination

32. MICROLEAKAGE

33. MICROLEAKAGE
• DEFINTION:
• Marginal defect of 10 microns is
created in a metallic restoration
following the intake of a cold drink or
a hot coffee
• Marginal defect of <50microns ,risk
of secondary caries is less

34. CURRENT THINKING ON THE
CAUSES OF PULP REACTION TO
RESTORATION
Pulpal injury is primarily due to micro leakage
through the gaps between the filling material and
walls of the cavity
Bacteria growing in these gaps elaborate products
that diffuse through the dentinal tubules &
irritate the pulp
Greatest amount of leakage occurred with silicate
cements, followed by composite and amalgam

35. AMALGAM;FAILURES
• The main causes of failures of
amalgam restoration include
• Secondary caries
• Marginal fracture
• Bulk fracture
• Tooth fracture

36. DENTAL AMALGAM
• In deep cavities there may be slight
to moderate pulpal inflammation
• Post operative thermal sensitivity
• Micro leakage around amalgam
restoration can be prevented by the
use of CAVITY VARNISHES and
more recently by the use of
BONDED AMALGAMS

37. RESIN BASED
COMPOSITES
• Incomplete polymerization which is
intensified in deep cavities
• Polymerization shrinkage(0.6% to 1.4%)
and imperfect adhesive bonding of the
material to the tooth cavity
• Bacterial leakage, marginal staining,
adverse pulp reactions and the
development of recurrent caries

38. composites
• Prevention is by the use of dentin
bonding agents
• Incremental curing

39. GLASS IONOMER
CEMENTS
• Relatively good adhesion
• Ability to release fluoride
• Biocompatibility has been a little clinical
concern
• Ph increases from initial value of 1 to the
range of 4 and as the setting reaction
progresses the ph value reaches 6.7-7

40. GLASS IONOMER
CEMENTS
• Severe pulp response with the P/L
ratio of luting cements.
• Fresh mix causes more damage than
set cement
• Leaching and release of fluoride

41. GLASS IONOMER
CEMENTS
• Early inflammatory reactions on
newly prepared dentin
• Cytotoxic -> calcium hydroxide liners
when RDT<0.5mm
• Liners should be used particularly
when glass ionomer is used as luting
agents

42. GOLD RESTORATIONS
• Insertion of gold foils may result in
pulpal reactions.
• Caused by the forces of
condensation, thermal conductivity,
cavity preparation, dehydration of
cavity and microleakage

43. GOLD INLAY
Potentially damaging not because of
irritation inherent in the gold but
thinner mixture of ZnPO4 which is used
for luting
large amount of pressure generated in
seating the inlay
Predisposition of cast gold to marginal
leakage

44. HEAT OF POLISHING
• If Polishing of amalgam, gold foil or
composites is done without any coolant
temperature may rise in pulp resulting in
pulpal injury.
• Polishing points made up of rubber create
more heat than cup brushes
• Less heat is produces if intermittent
polishing is done at low speeds using
coolants

45. PROCEDURES FOR PULP
PROTECTION
PULP CAPPING
a) Indirect pulp capping
b) Direct pulp capping

46. PULP CAPPING
• DEFINITION:
• Placement of dental material over
exposed or nearly exposed pulp to
initiate the formation of irritation
dentin at the site of injury

47. Treatment objectives:
• To seal and protect the pulp against
bacterial micro leakage
• Encourage the pulp to wall off the
exposure site by inducing dentin
bridge
• Maintain the vitality of underlying
pulp tissue

48. INDIRECT PULP
CAPPING
• When there is danger of exposing the pulp
in a deep seated carious lesion some decay
is left and Ca(OH)2 is placed
• Pulps that are
• In transition stage
• In the stage of Chronic partial pulpitis
• Without liquefaction necrosis
are amenable to IPC

49. DIRECT PULP CAPPING
• Done in case of PIN POINT &STERILE
pulp exposures
• No signs and symptoms of PD organ
degeneration
• No observable hemorrhage from
exposure site
• Reparable dentin at the periphery

50. MATERIALS USED FOR PULP
PROTECTION
• Cavity Varnishes
• Liners
• Bases

51. IDEAL REQUIREMENT
• Should be capable of creating an impervious layer
on cut vital dentin in a thickness which never
impinges on the bulk of the restorative material
nor compromises the mechanical properties of the
restoration.
• Biologically compatible
• Chemically compatible
• Should not discolor
• Should harden quickly
• Should withstand the condensation forces
involved in placing permanent restoration

52. VARNISHES
• DEFINITION:
• A solution of natural
gum, synthetic resins, or resins
dissolved in organic solvents such
acetone ,ether, or chloroform

53. CAVITY LINER
DEFINITION:
Thin layer of cement such as
Ca(OH)2 suspension in an aqueous or
resin carrier used for pulp protection

54. LINERS
• These are much thicker than varnishes,
but still will not exceed the leakage space
around the restoration
• Usually made up of film forming materials
like varnishes, but they contain
therapeutic agents which create their
greater film thickness.
• Film thickness: 0.25-0.50mm
• Usually applied to dentin only

55. LINERS
• Calcium Hydroxide ( VLC Dycal )
• Traditional Glass Ionomer cements
• Reinforced Zinc Oxide Eugenol
cements
• Fluoride liners

56. BASES
• DEFINITION:
• Layer of insulating sometimes
medicated cement placed in deep
portion of preparations to protect
pulpal tissue from thermal and
chemical injury

57. BASES
• Bases are used to provide thermal
protection for the pulp and to
supplement mechanical support for
the restoration by distributing local
stresses from the restoration across
the underlying dentin surfaces.
• Film thickness typically:0.50-0.75mm

58. BASES
• Zinc Oxide Eugenol cements
• Calcium hydroxide cements
• Zinc Polycarboxylate Cements
• Glass Ionomer Cements
• Mineral tri oxide aggregate

59. MATERIAL
• CAVITY VARNISH
• CALCIUM HYDROXIDE CEMENT
• ZINC OXIDE EUGENOL CEMENT
• ZINC POLYCARBOXYLATE
CEMENT
• GLASS IONOMER CEMENTS

60. DENTAL VARNISH

61. VARNISHES
• Applied in thin film
• Thickness should no exceed the
leakage space at the restorative
material-tooth substance interface
• Film thickness: <0.25mm
• Vanishes are applied to all prepared
dentine surfaces and frequently on
prepared enamel.

62. USES:
• Barrier against passage of irritants
• Reduces post operative sensitivity
• Should not be in cements that use
adhesives to increase bond strength
to the tooth structure

63. PHYSICAL PROPERTIES
• Thermal Insulator
• Electrical Insulator
• High LCTE
• Poor Wetting

64. BIOLOGIC COMPATIBILITY
• Varnish has an irritating effect on P-
D organ at certain effective depths
• Irritating ingredients are always the
organic solvents and their cooling
effects when they evaporate.

65. CALCIUM HYDROXIDE
CEMENT
LINER IN DEEP CAVITIES
PULP CAPPING AGENT
Herman in 1920 suggested calcium
hydroxide for the treatment of dental
pulp.

66. COMMERCIAL NAMES
Dycal
Life
Care
• Light cure:
Prisma VLC Dycal

67. APPLICATIONS IN
OPERATIVE FIELD
• Used as a liner base &sub base in
deep cavities
• Used as a pulp capping agent

68. AVAILABLE AS
• POWDER FORM
• ONE PASTE SYSTEM
• TWO PASTE SYSTEM

69. ADVANTAGES
• Easy manipulation
• Rapid hardening in thin layers
• Good sealing characteristics
• Beneficial effects on carious dentin
and exposed pulp
• Ph of the set cement is 12.24

70. DISADVANTAGES
• Low strength even when fully set
• Exhibit plastic deformation
• Weakened by exposure to moisture
• Dissolve under acidic conditions when
microleakage occurs.

71. Ca(OH)2:ITS EFFECTS
ON PULP
• TWO SCHOOL OF THOUGHTS:
• 1)Acts as a counter irritant and
causes coagulation of the adjacent
PD organ
• 2)Activation of ATPase which
enhances dentin mineralization

72. CALCIUM HYDROXIDE
ON PULP
A B

73. Ca(OH)2; EFFECTS ON THE PULP
• It acts as chemical neutralizer for
acidity of silicate cements,Zn(PO)4
cements and prevents the
penetration of acids into the pulp
• There is significant elevation of PH in
dentin subjacent to Ca(OH)2 after 1
to 3 days

74. BY WILSON &KENT IN
1972
GLASS IONOMER
CEMENTS

75. SYNONYMS
• POLY ( ALKANOATE) CEMENT
• GIC
• ASPA ( ALUMINO SILICATE
POLYACRYLIC ACID)

76. APPLICATIONS OF GIC
• Anterior esthetic restorative material
for class III cavities
• For eroded areas and class v restorations
• As liners and bases
• For core build up
• To a limited extent as pit and fissure
sealant
• For cementation of cast alloys, Porcelain
restorations and Orthodontic band.

77. BIOLOGIC PROPERTIES
• Early inflammatory reactions on
newly prepared dentin
• Cytotoxic -> calcium hydroxide liners
when using near to the pulp
• Liners should be used particularly
when glass ionomer is used as luting
agents

78. ADVANTAGES
• Easy mixing
• High strength and stiffness
• Leachable fluoride
• Good resistance to acid dissolution
• Potentially adhesive characteristics
and translucency

79. DISADVANTAGES
• Initial slow setting
• Radiolucency
• Possible pulpal sensitivity

80. RESIN BASED GLASS
IONOMER CEMENTS
• Recent addition to spectrum of
materials
• Also called “Hybrid Ionomer”
• Can be used as Cavity liners, Bases,
Core build ups and Luting agents
• Also used for cementation of
Orthodontic brackets

81. ADVANTAGES OF
RESIN MODIFIED GI
CEMENTS
• Stronger
• Fluoride release
• Good radio opacity
• Satisfactory wear resistance
• Bond strength-excellent
• Minimal or no post operative
sensitivity.

82. ZINC OXIDE EUGENOL
CEMENT

83. ZINC OXIDE EUGENOL
CEMENT
• Cavity liners in deep cavities
• Cementation of crowns in fixed
partial dentures
• Provisional restoration of teeth
• Root canal sealer
• Soft tissue pack in oral surgery and
periodontics

84. EUGENOL, its effect on
PD organ
• Has anodyne properties
• Inhibits action potential in nerve fibers of
dental pulp
• Has inhibitory effect rather than
destructive effect on bacterial growth
• Shouldn’t be placed directly on the
exposed pulp, an intervening layer of
dentin must be present

85. CLASSIFICATION
• Type I - For temporary
cementation
• Type II - For permanent
cementation
• Type III - Temporary filling material
and
Thermal insulator
• Type IV - Cavity liners

86. Biologic
properties:
•Eugenol in set cement produces anodyne
and obtundant effect on the pulp in deep
cavities
• Materials maintain good sealing
characteristics
• Ph is 6.6-8 pulpal response is mild
Thermal properties:
Excellent thermal insulating properties
PROPERTIES

87. ADVANTAGES
• Minimal biologic effects
• Good initial sealing properties
• Adequate strength
• Effective insulating material and
so prevents galvanic action of
amalgam thus inhibiting corrosion
• No heat rise during setting

88. DISADVANTAGES
• Lacks strength
• Has slight demineralizing action as it
chelates with calcium ions tooth
structure

89. ZITEMP
Applications:
Temporary restoration
Temporary cement for crowns
Cavity liner under most restorative
materials.
ZITEMP is a quick set
easy mix zinc oxide-
eugenol composition
for thermal insulation
and temporary
restoration.

90. CAVIT
• Contains
ZnO,Ca(SO)4,Zn(SO)4,glycolacetate, poly
vinyl acetate, polyvinylchloride acetate, tri
ethanolamine and red pigment
• Material sets when saliva reacts with
Ca(SO)4,ZnO,Zn(SO)4
• Excellent sealing properties

91. FLOURIDE LINERS
• Calcium mono fluoro phosphate
• potassium fluoro zirconate
• Effective in reducing thermal
conduction into pulp by metal
restorations
• Decreases the acid solubility of
dentin

92. ZINC
POLYCARBOXYLATE
CEMENT

93. APPLICATION
• Cavity liners and Base materials
• Provisional restorative materials.
• Cementation of cast alloys, porcelain
restorations and orthodontic bands

94. • Can be used as base with of without
underlying Subbases
• It can be used as base for preparation
with effective depths as low as 0.5 mm
• It has an ability of chemo-physical
adhesion to the tooth structure
• Provide only a mechanical diffusion barrier
and thermal insulation
• The only therapeutic to be used is calcium
hydroxide cement

95. BIOLOGIC EFFECT
• Comparable to or less than ZOE
• Good biocompatibility
Low intrinsic toxicity
Rapid increase in the cement Ph towards
neutralization
Localization of polyacrylic acid
Minimal movement of fluid in dentinal
tubule in response to cement

96. ADVANTAGES
• Low irritation
• Adhesion to the tooth substance and
alloys
• Easy manipulation
• Strength, Solubility and Film
thickness comparable to those of
zinc Phosphate cement

97. DISADVANTAGES
• Need for accurate proportioning for
optimal properties thus more critical
manipulation
• Lower compressive strength and
greater viscoelasticity than zinc
phosphate cement

98. MINERAL
TRIOXIDE
AGGREGATE

99. COMPOSITION:
• Powder consists of
• Tri calcium silicate
• Tri calcium alluminate
• Calcium sulfate di hydrate
• Bismuth oxide
• Calcium carbonate
• Calcium sulfate

100. ADVANTAGES:
• Ph value after mixing is 10.2
• After 3 hrs is 12.5
• Radio opacity greater dentin
• Least soluble

101. MTA:
• Biological response of MTA is
because of
• Its high ph
• Presence of calcium ions

102. PULP PROTECTION
DURING RESTORATIVE
PROCEDURES
• Preserving the dentin thickness
• Ultra high speed with a water coolant
• Small sized & sharp burs
• Minimal amount of pressure
• Avoiding the use cleansing agents for
toileting of the prepared cavity

103. THANK YOU