Pulp Protection

• The restoration and maintenance of dental health through adequate

restorative treatment in order to protect pulp function is the main

purpose of restorative dentistry.

• The dental pulp is a soft connective tissue of mesenchymal

origin present within the pulp chamber and root canals of teeth.

• It is not considered an external tissue, yet its exposure to external

stimuli is unceasing due to several factors that make the pulp

extremely sensitive to environment outside.

• Protection of dentin-pulp complex is an important factor in

pulp vitality during operative procedures.

• This involves the avoidance of thermal stimuli caused by

operative procedures, toxicity of restorative materials and

bacteria penetration.

• The dentin and pulp must be considered as one organ

because of their intimate relationship between cellular

tissue within dentin and peripheral pulp tissue.

Dentin Sensitivity

PULP IRRITANTS

• Bacterial irritants

• Trauma

• Iatrogenic:

i. during tooth preparation

ii. Orthodontic movement of tooth

iii. Periodontal and periapical curettage

iv. use of chemicals

v. idiopathic

Pulpal irritants

A) Bacterial irritants

(Most common cause for

pulpal irritation)

1-Caries

B) Traumatic

Tooth fracture

Luxation

Avulsion

Parafunctional

habits like bruxism

2- Periodontal

pocket and abscess

1- Acute trauma 2- Chronic

Trauma

C) Iatrogenic:

1. During cavity preparation

a) Heat production during cutting procedures:

Pulp temperature 11°C Destructive reaction

Pulpal temperature is critical and must not exceed normal

values in dental restorative procedures.

Clinical research has shown irreversible damage to pulp tissues

at levels of 60% at 5.5°C and 100% at 11°C..

b) Pressure exerted:

Pressure of hand or rotary instruments Nuclear aspiration of odontoblasts

or nerve endings from pulp tissues into the dentinal tubules Disturb

odontoblasts metabolism leading to their complete degeneration and

disintegration.

c) Remaining Dentin Thickness (RDT)

Use of chemicals

Temporary & permanent fillings, bases, liners, and use of alcohol

that leads to pulpal injury due to its cytotoxicity, acidity, heat

formed and marginal leakage

Chemical irritants applied to dentin can result in

damage and disorganization in the subadjacentpulp

• Direct pulp capping

• Indirect pulp capping

Conventional methods

Direct Pulp

Capping

Direct pulp capping is placing a

biocompatible material over the

exposed pulp to maintain

vitality and promote healing.

WHY?

1) To maintain the vitality of the remaining pulp tissue

2) To prevent root canal treatment

3) To help conserve tooth structure

Indications

Recent small mechanical exposure of

pulp during (< 24 hours):

a) Tooth preparation

b) Traumatic injury.

No or minimal bleeding at the

exposure site.

Contraindications

Wide pulp exposure

Pre-operative

history of

Spontaneous

pain

Presence of bleeding at

exposure site

Radiograph show any

pulp pathology

Clinical Procedure3.When vital & healthy

pulp is exposed, check

fresh bleeding

2. Isolate the tooth

with rubber dam

1. Administer local

anesthesia

4. Clean the area with

saline solution

5. Dry it with a

cotton pellet

6. Apply calciumhydroxide

(preferably Dycal) over the

exposed area

Indirect Pulp Capping

In indirect pulp capping, all caries are removed

except the ones that lie adjacent to the pulp. Caries

near the pulp is left in place to prevent pulp exposure

and preparation is enclosed with a biocompatible

material.

Indications

1. Deep carious lesion near the pulp tissue but not involving it

2. No mobility of tooth

3. No history of spontaneous toothache

4. No tenderness to percussion

5. No radiographic evidence of pulp pathology

6. No root resorption or radicular disease should be present

radiographically.

Root resorption

Clinical Procedure

It’s the same procedure as the direct pulp capping except that the

pulp is not exposed. A thin layer of dentin and some amount of

caries is left to avoid exposure.

Placement of calcuim hydroxide and zinc

oxide eugenol dressing after excavation

of soft caries

Factors affecting Pulp Capping

success

1) Age of the patient: Due to vascularity of the pulp, young patients have

greater potential for success than older ones

Young patient Old patient

2) Type of exposure: Mechanically done pulpal exposure has better prognosis than

exposure caused by caries, due to less pulpal inflammation and deleterious effect of

bacterial toxins on the pulp

3) Size of the exposure: In large exposures, it is difficult to control

the hemorrhage and tissue seepage. Small pinpoint exposures are easy

to manage and have a greater potential for success

3) History of pain: If previously pain has not occurred in the tooth, the

potential for success is more

Conventional Materials

Materials used for Pulp

Protection

Recent Materials

Base Sealer Liner

1) Zinc oxide eugenol liners

2) Calcium hydroxide

3) Flowable composites

4) Glass ionomers

1) Zinc Oxide Eugenol

2) Zinc phosphate cement

3) Polycarboxylate cement

4) Glass ionomer cement

Sealer

Indications

• To seal dentinal tubules

• To treat dentin hypersensitivity.

An adhesive sealer is commonly used under indirect restorations.

For application, cotton tip applicator is used to apply sealer on all

areas of exposed dentin.

Ether or

chloroform

Organic

copalResin

gum

Solvent

evaporates

Definition:

It is an organic copal or resin gum

suspended in solutions of ether or

chloroform.

When we put it on the tooth surface the

organic solvent evaporates leaving a

protective film

Two coats of varnish should be applied

using a small cotton pellet to ensure

sufficient wetting of cavity walls

VARNISH

Indications

To seal the dentinal tubules

Dentinal

tubules

Open Dentinal

tubules

Sealing dentinal

tubules with varnish

Dentinal tubules

blocked by varnish

2. Protects the tooth from

chemical irritants from cements

reducing postoperative pain

3. Reduces microleakage

around restorations

1. Prevents discoloration of tooth

with an amalgam restoration by

preventing migration of ions into

the dentin

Under Composite

Resin

Varnishes dissolve in the

monomer of the resin &

also interfere with their

polymerization of resins

With Glass Ionomer

Restorations

It interferes the bonding

of tooth to these cements

Contraindication

s

• Liners can be classified as :

Thin film liners( 1-50µm)

a. solution liners ( varnish:2-5 µm)

b.suspension liners ( zinc oxide / calcium hydroxide 20-25

µm)

Thick film liners ( 200 -1000 µm)

a. GIC ( type III)

LINERS

Commercially available calcium hydroxide liners are DYCAL ( dentsply )

and single paste systems like CALCIMOL LC ( Voco) and Septocal LC (

Septodont)

1- Calcium

hydroxideMost common agent considered as the

“gold standard” of direct pulp capping

materials against which new materials

should be tested

Advantages:

1. Causes dentin mineralization by activating the enzymeATPase

2. Stimulates reparative dentin formation

3. Biocompatible

4. High pH (12.5) neutralizes acidity of silicate and zinc phosphate

cements

Disadvantages:1. Low strength

2. High solubility Dissolves rapidlyUsed over small areas requiring pulp

protection / Applying glass ionomer or zinc phosphate base to prevent its

dissolution.

When it

dissociates:

2- Glass ionomers

Renewable source of

fluoride under

restorations

Reduce the

incidence of

caries

Fluoride

Glass ionomer cements (GIC):

Bond to tooth structure

Act as a thermal barrier

Ability to bond in a moist environment

Easy to use.

Anticariogenic.

Light-cured resin-modified

glass ionomers (RMGIs)

Provide good adhesion to both tooth structure

and restorative materials

High strength

Flexible (low modulus of elasticity)

Dual-setting reaction:

1) Light-activated, methacrylate crosslinking

reaction

2) Slower, delayed, acid-base reaction

Which gives RMGIs an additional period of

maximum flexibility to absorb stress from the

adjacent shrinking composite.

BASES

Classification of

bases

Protective

basesSedative bases Insulating bases

They protect the

pulp before

restoration is

placed

They help in calming the pulp

which has been irritated by

mechanical, chemical or

other means

They protect the

tooth from thermal

shock.

Bases should have sufficient strength so that they can withstand

forces of mastication and condensation of permanent

restorations.

Excellent

sealing quality.

Bacteriostatic

in nature.

Anodyne

effect.

Chemically

bonds to tooth

Antibacterial

properties

Fluoride release

Anticariogenic

property

Chemical

bond to tooth

Well tolerated

by the pulp.

Materials used as

bases

Zinc oxide

eugenol

Zinc phosphate

cement

Reduces the thermal

conductivity of

metallic restorations

Blocks undercuts in

the preparation wall

in case of cast

restorations.

Polycarboylate

cementGlass ionomer

cement

Pulp Protection according with

depth of tooth

preparation

Recent Materials used for Pulp

Protection

Biodentin

Biodentine is a calcium-silicate based material.

Advantages:

Biocompatible so no pulp inflammatory

responses

Can be used wherever dentin is damaged

Outstanding sealing properties

Used as base or liner under composite

restorations

Adequate compressive and flexural strength

Creates faster dentin bridges

Better properties than glass ionomer and

calcium hydroxide

Radio opacity for following up

Biodentine was faster than MTA

Enhanced mechanical properties

Good marginal seal

placement of MTA was more time consuming and technically more

difficult in comparison to Biodentine

Biodentine showed, similar efficacy to MTA.

A recent study evaluated the efficacy of Biodentine in a series of 15

case with follow up of 12 to 24 months, and authors concluded that

all 15 cases were asymptomatic during follow up period therefore

suggesting the use of Biodentine as vital pulp therapy material

(a & b) Pre-operative photograph showing in 11 with pulp exposure

(c) Preoperative radiograph

(d and e) A3mm layer of Biodentine located over the uncovered pulp

(f) Immediate post-operative radiograph showing 3mm barrier of Biodentine

(g)Post-operative radiograph after 18 months showing a well-formed radio-

opaque barrier

(h) Post-operative recall photograph after 18 months

Clinical

Procedure:

Mineral Trioxide Aggregate

(MTA)

1) Characteristics: Non-toxic material

Low or no solubility

Stimulate reparative dentin development

by a normal defending process of an

early pulpal wound healing (evidence

was the presence of odontoblast like

cells)

Minimal inflammation at early healing

stage

2) Composition:a. Tricalcium silicate

b. Tricalcium aluminate

c. Dicalcium silicate

3) Manipulation:Mixed with sterile water in a 3:1 powder to liquid ratio

Setting time: MTA sets in 5 minutes

4) How does MTAwork?

Tricalcium

oxideTissue fluids

Calcium

hydroxide

Hard tissue

formation

5) Clinical

procedure

a) Radiograph before performing the operative procedure

b) A Photograph that shows the uncovered pulptissue

c) Photograph showing settlement of MTA above the pulp tissue

d) Radiograph after restoring the tooth permenantly

e) Six months follow up radiograph

Why is MTA better than Calcium

Hydroxide?

MTA Calcium hydroxide

VS.

1. Rapid cell growth promotion in vitro

2. Greater ability to maintain the integrity of pulp tissue

3. Thicker and rapidly formed dentinal bridge

4. Less hyperemia

5. Lower level of necrosis

• Histological evaluations of exposed pulp tissue from animals capped with

MTA have shown the formation of a thicker dentinal bridge, with low

inflammatory response, hyperemia and pulpal necrosis compared to

calcium hydroxide cement.

• Calcium hydroxide does not adhere to dentine and lacks the ability to seal.

• Tunnel defects in dentine bridges under calcium hydroxide dressings can

act as pathways for microleakage (Cox et al. 1985). This material also has a

tendency to dissolve over time (Schuurs et al. 2000).

• MTA appears to induce the formation of a dentin bridge at a faster ratethan

calcium hydroxide

Response of Human Dental Pulp Capped with MTA and Calcium

Hydroxide Powder- MLR Accorinte et al Operative Dentistry 2008:33

Thercal

1) Characteristics:

TheraCal is a light cured, resin modified

calcium silicate filled liner designed for use in

direct and indirect pulp capping, as a protective

base/liner under composites, amalgams,

cements, and other base materials.

2) Composition:Tricalcium silicate particles in a hydrophilic monomer that provides significant

calcium release making it a uniquely stable and durable material as a liner or base.

3) Mechanism:Calcium release stimulates hydroxyapatite and secondary dentin bridge formation

4) Indications:Any pulpal exposures (carious exposures, mechanical exposures or traumatic

exposures )

Clinical

Procedure

Why is Thercal better than MTA & Calcium

Hydroxide?

MTA Calcium hydroxideThercal

VS.

Higher calcium releasing ability

Lower solubility than either MTA or Calcium Hydroxide due to

the capability of TheraCal to be cured to a depth of 1.7 mm

which avoids the risk of dissolution.

• Thera-Cal proved to be an ion-leaching material able to release calcium and

hydroxyl ions for a period of at least 28 days, and it released significantly

more calcium than either ProRoot MTA or Dycal throughout the test

period.

• The findings of this study suggest that the resin portion of TheraCal

(comprising hydrophobic and hydrophilic monomers) is able to

promote/sustain Ca and OH ion release within the wet surgical site (on the

tooth pulp and/or dentine) and could favour the interaction of the

formulation with the hydrophilic tooth dentine.

Chemical–physical properties of TheraCal, a novel light-curable MTA-like

material for pulp capping- M. G. Gandolfi IEJ 2012:45

• Most recent studies report long term success rates close to 90% for laser

assisted pulp capping , compared to a success rate of about 60 % with

traditional methods.

• The use of the Er,Cr:YSGG laser allows cavity preparation to be completed

with only one instrument in contrast to alternate use of high and low speed

rotary instruments and other laser wavelengths ( CO2, Nd:YAG and diode

lasers) which cannot be used for ablation of hard tissue.

Lasers in pulp capping

Erbium chromium laser in pulp capping treatment – dr.giovanni J Oral laser application

2006;6

• CO2 and erbium lasers are more superficial in their interaction with tissue

than the diode and Nd: YAG wavelengths which penetrate more deeply and

have a greater capacity for scattering .

• Coagulating effect of laser guarantees a dry operating area with no bleeding

and creation of zone of necrosis that is more superficial compared to

chemical pulp capping agent.

• Only erbium laser limits a pressure increase in dental cavity thus avoiding

the risk of pushing either mechanically or manually infected dentinal chips

into the pulp tissue during caries removal.

Erbium chromium laser in pulp capping treatment – dr.giovanni J Oral laser application

2006;6