1. Caries and Restorative
Assalaam Alekum
15/4/2014
Pulpal reactions to
Caries and Restorative
procedures
Dr. Gaurav Garg, Lecturer
College of Dentistry, Al Zulfi, MU.

2. Pulpal reactions to caries Pulpal reactions to restorative Procedures
Contents
Introduction
Cells of the pulp
Pulpal reactions to caries
Pulpal reactions to restorative Procedures

3. Introduction
Embryologically and physiologically Dentin and pulp are so intimately related that dentin can be considered as the peripheral calcified portion of the dental pulp.
However This intimate relation extends beyond embryological and physiologic considerations.
It has important clinical implications.
It means that pulp would react when dentin is injured whether the injury is caused by caries, attrition, abrasion, erosion or operative procedures.

4. Dentin
Odontoblastic layer
Cell Free zone
Cell Rich zone

5. Dynamic Dental Pulp Responds to external stimuli in a variety of ways
Ability to form dentin throughout life
Potential for regeneration and repair diminishes with age
Very sensitive to thermal stimuli
Encased in a low compliance environment
Scarcity of collateral circulation

6. Cells of the Pulp
Formative cells ( odontoblasts, fibroblasts )
Defense cells ( Histiocytes , Lymphocytes )
Reserve cells (undifferentiated mesenchymal cells)

7. MODES OF IRRITATION TO PULP
1. DIRECT-
Direct irritation to the pulp-Dentin organ- Carious/ iatrogenic pulp exposure
Allows direct access for the oral flora and other irritating ingredients
2. INDIRECT-
Irritating toxins/chemicals enter through the dentinal tubules

8. Reaction of the pulp-Dentin organ to stimulation/irritation
Healthy reparative reaction
Unhealthy reparative reaction
Destructive reaction

9. Healthy reparative Reaction
Most favorable response
Sclerotic dentin and/or calcific barriers followed by
Normal secondary dentin
Healthy reaction occurs without any disturbances in
the pulp

10. Unhealthy reparative Reaction
Degeneration of the odontoblasts Dead tracts Complete cessation in formation of secondary dentin Accompanied by mild pathological and clinical changes of reversible nature Irregular type of tertiary dentin – Irritation dentin Odontoblasts will pave over this reparative dentin and form secondary dentin

11. A – Dead tracts
C – Reparative dentin

12. Limitations of tertiary dentin
Permeable
Reduces the capacity for further defensive action
Less elastic than primary dentin

13. Destructive Reaction
Most unfavorable response
Loss of odontoblasts/outer protective layer
Involvement of pulp tissue proper
Inflammation
Chronic inflammation/Abcess formation
Necrosis

14. T- stained tubules A- abcess CI- cellular infiltration V- calcified vessels and hard tissue formation

15. Pulpal reactions to
Caries

16. Dental caries - Facts
Localised , Destructive and Progressive infection
Destroys dentin at a rate of 1mm/six months
Foci of pulpal inflammation occurs when caries is within 750 microns from the pulp

17. Pulpal Reaction to caries
Three basic reactions protecting pulp
Decrease in dentin permeability
Tertiary dentin formation
Inflammatory & Immune reactions

18. Dentin permeability - Importance
Channels of diffusion – Dentinal tubules
More no of tubules per unit area towards pulpal side as compared to peripheral dentin
Fluid permeation is proportional to Tubule diameter and number
Clinical importance – Dentin beneath a deep cavity preparation is more permeable than dentin underlying a shallow cavity

19. Decrease in dentin permeability
First defense to caries – SCLEROTIC DENTIN
Combination of
An increased deposition of intratubular dentin
Direct deposition of mineral crystals (Whitlokite) into narrowed dentinal tubules

20. Whitlockite crystals

21. Tertiary Dentin
Occurs over a Longer period than does sclerotic dentin
Mild stimuli quiescent odontoblasts
Reactionary Dentin
Observed when initial dentin demineralisation occurs beneath non cavitated enamel lesion

22. Tertiary Dentin
Tertiary Dentin

23. Tertiary Dentin Tubular dentin Fibrodentin
Aggressive lesion cytocidal to odontoblasts
Repopulation of the disrupted odontoblast layer
Reparative dentin
Tubular dentin Fibrodentin

24. Pulpal Immune Response
Early response is characterised by focal accumulation of chronic inflammatory cells
Mediated initially by odontoblasts and later by dendritic cells
Progressive inflammation

25. Pulpal reactions to Local Anaesthetics

26. Effect on pulp Intact pulpal blood flow is critical
Dental pulp is enclosed in a rigid chamber and cannot benefit from collateral circulation
Reduction of blood flow – Reduction in clearance of large molecular weight toxins or waste products
Anaesthetic delivered through an intra osseous route or periodontal ligament route can compromise the inflamed pulp’s ability to heal by reducing the blood flow

27. Pulpal reactions to Restorative procedures

28. restorative procedures causing pulp injury
Tooth Preparation (Restorations/ Crown)
Acid Etching
Chemicals from restorative materials (Cements/ Bases)
Lasers
Effects of Caries, Microleakage, Restorative procedures and materials is Cumulative
restorative procedures causing pulp injury

29. Physical irritation from a procedure
Heat
Dessication
Vibration

30. First principle to eliminate 2 sources of pulp injury is
NEVER CUT DRY

31. Remaining Dentin Thickness
Most critical factor in determining the intensity of pulp reaction is RDT
2mm of RDT provides adequate protection
So it is advocated that if RDT < 2mm
USE OF A PROTECTIVE BASE IS MANDATORY

32. Effect of Hand instruments
Sharp hand cutting are most biologically accepted wherein the energy used is completely dissipated in the actual cutting
Excessive pressure in decreased effective depths causes aspiration of the odontoblasts

33. CR- Cell rich zone
Aspirated odontoblasts

34. Effect of Rotary instruments
Rotary abrasive instruments (stones) are not recommended for cutting in vital dentin, as their abrasive action will elevate the temperature of surrounding dentin. It may crush vital dentin
It should be confined to enamel
Rotary cutting instruments (burs) are biologically acceptable if used over RDT of 2mm or more
Carbides provides more cool cutting

35. Other factors to be considered
Extensiveness and Duration of preparation time is directly proportional to extensiveness of the reaction of the pulp dentin complex

36. REFERENCES 1. Pathways of pulp tenth-edition- Stephen Cohen
2. Endodontics-sixth edition- Ingle
3. Endodontics- Franklin S. Weine
4. Textbook of Endodontics- Walton Torabinezad

37. Thank you