PULPAL CONSIDERATIONS

Dr. Mahvesh Hasan

FCPS II TRAINEE

Dept of Operative Dentistry

DIKIOHS

Importance of remaining dentin

thickness

0.5 mm

1 mm

2 mm

Remaining dentin

thickness

25 %

10 %

Minimal or Nil

Effect of toxic

substances

Causes of Pulpal Inflammation

Types of stimulus Examples of stimulus

Physical Thermal, electrical

Mechanical Handpiece,

traumatic occlusion

Chemical Dental

materials, Caries

Biologic Bacteria from saliva

Response to bacteria

Even early enamel caries lesions that extend less than one-fourth of the way to the DEJ have been shown to induce a slight pulpal reaction

Response to bacteria• Reparative Dentin

• Reactionary Dentin

• Dentin Sclerosis

Response to bacteria

Marginal leakage

Response to instrumentation

Research has shown that 3% to 22% of teeth with full coverage crowns require

endodontic therapy

Response to instrumentation• The degree of pulpal reaction is dependant on the

amount of friction and dessication

• Frictional heat generated by tooth preparation can

result in burn lesions in the pulp and abscess

formation

• Dessication results in dentinal fluid being lost from

tubules

• Pressure has greater effect on temperature rise than

rotational speed

Clinical impact

• Preparation using low-speed rotary instrumentation

has been shown to be more traumatic to the pulp

than high-speed preparation.

Keys to minimizing adverse pulpal

reactions from rotary instrumentation• Adequate air-water coolant spray

• Light pressure

• Sharp rotary cutting instruments

• Preservation of tooth structure

Hydrodynamic Theory

When a stimulus causes the slow fluid movement to

become more rapid, nerve endings in the pulp are

deformed , creating a response that is interpreted as

pain

Classification and types

• CAVITY SEALERS: Varnish, Adhesive sealers

• CAVITY LINERS: Glass ionomer, Calcium hydroxide

• Bases: - 1. Zinc phosphate cement.

2. Reinforced zinc oxide / eugenol

cement.

3. Zinc polycarboxylate cement.

4. Glass ionomer cement.

Cavity sealers• Varnish

• Adhesive sealers

• Provide protective coating and barrier to leakage

• Coat all walls of the cavity

• Provide various degrees of seal

Varnish• Material applied in thin film thickness usually 2 – 5

microns.

• It could be applied to all prepared cavities on both

enamel and dentin.

• Protective coating and Barrier to leakage

• Seals the dentinal tubules and reduces leakage

around a restoration.

• Provides no thermal

insulation

 

VarnishComposition:

• Organic copal resin or synthetic gum dissolved in

solution of ether, chloroform or acetone.

• This solution evaporates rapidly after placement on

the tooth leaving a thin layer of semi-permeable

membrane.

• The thickness of this layer is 5 – 25 microns

depending on the type of the solvent and the

number of applications.

• Application processo Applied with either a small disposable applicator or a cotton pellet.

o Thin coating of the varnish on the walls, floor, and margin of the cavity preparation.

o Apply a second coat.

Adhesive sealers

• Provide sealing as well as bonding at the interface

between restoration and cavity preparation walls.

Concerns about use of adhesive

sealers under amalgam• Barrier to corrosion products

• More technique sensitive than varnishes

• Expensive and time consuming

• Pooling of resin

• Incorporation into amalgam

Cavity Liners

• Dental liners provide a thin barrier (0.5 mm) that

protects the pulpal tissue and provide some type of

therapeutic benefit.

• Main function : Physical barrier and therapeutic

effect

• It does not function as thermal insulators.

• It is applied only to dentin.

Cavity liners• Calcium Hydroxide

• GIC

Calcium Hydroxide

• Indications for useo Protects the pulp from chemical irritation by its

sealing ability.

o Stimulates the production of reparative or secondary dentin.

o Compatible with all types of restorative materials.

• Application processo Placed only on dentin.

o Placed directly over the deepest portion of the preparation.

• Disadvantages:

• Has no obtundant property.

• Not strong enough to provide reliable support for a

restoration under heavy occlusal stresses, so a

strong base material should be used to cover it.

Glass ionomer cement

• Composition:

• Powder: → Fine ionomer silicate glasses

(Alumino-silicate).

• Liquid: → Aqueous solution of copolymer of

polyacrylic acid.

• Recommended as liners under resin

composites to reduce microleakage

Advantages:

• Adhesive to tooth structure

• Anticariogenic: → Through the release of fluoride

ions, which will be up-taken by hydroxyapatite to

be changed into → Fluoro-hydroxyapatite, which is

more acid resistant.

• Semi-translucent color → when dealing with anterior

restorative material it will not affect the color of the

final restoration.

• Disadvantages:

• 1- Water sorption, leading to:

→ Leakage.

→ Discoloration.

→ Penetration of microorganisms.

• 2- Low wear or abrasion resistance: → So, when

used as a restoration, it should not be placed in

stress bearing areas.

Bases• Insulation

• Bulk build up

• Blocking of undercuts

• Resin composite exhibits low thermal diffusivity that

a thermal insulating base should be unnecessary

• Insulating base for thermal protection should be

used under metallic restorations

• Thickness 0.5-0.75 mm