Dynamics of Dental Pulp & Periapical Pathologies

Deepti AwasthiP G student

CONTENTS

• Introduction• Development• Anatomy• Structural features• Blood vessels• Lymph vessels• Nerves • Functions• Differences in primary & permanent pulp

organ

• Age changes• Classification of pulpal pathologies Reversible pulpitis Irreversible pulpitis Acute apical periodontitis Phoenix abscess Periapical granuloma Radicular cyst External resorption Internal resorption Pulp necrosis• Conclusion• References

Definition

Dental pulp, a small mass of connective tissue, blood vessels, and nerves located in a chamber within the dentin layer of a tooth. The pulp chamber is found in the crown and the root of a tooth.

Mosby's Medical Dictionary, 8th edition. © 2009, Elsevier

Introduction

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Development

Regeneration of tooth pulp dentin

ANATOMY

• General features volume

• Coronal pulp 6 surfaces pulp horns

• Radicular pulp single , multiple tubular shape growth –more dentin – pulp gets

narrower

• Apical foramen avg. size in adults location & shape may undergo

changes frequently , there are 2 or more

foramina seperated by a portion of dentin & cementum or by cementum only.

orbans

• Accessory canals from radicular pulp laterally through the

root dentin to the pdl tissue apical third clinically significant in spread of infection

Mechanism of accessory canal formation :

Textbook of Endodontics – Nisha Garg

STRUCTURAL FEATURES

• Histologically,

Human anatomy II, DDS 09

• Principal cells : odontoblasts fibroblasts undifferentiated mesenchymal macrophages lymphocytes dendritic cells• Intercellular substances :

Intercellular substances

• Dense & gel like• Acid muco polysaccharide & protein

polysaccharide• During early development, chondroitin A,B &

hyaluronic acid.• Lends support to the cells of the pulp• Transport of nutrients & metabolites• Gag –hydrophilic,forms a gel – high tissue fluid

pressure.orbans

Fibroblasts

• Most numerous• Function –• Stellate shape & extensive processes• Electron micrograph – RER , mitochondria etc• Young pulp – divide & are active in protein

synthesis• Older pulp – spindle shaped , fibrocytes• Mature & immature pulp-

orbans

• Dual function• Inflammation & healing

• Fibres – type I & III length – 10 – 100nm cross striation at 64 nm• After root completion, pulp matures &

bundles of collagen fibres increase in number.• Apical region

orbans

• Fibres are more numerous in radicular pulp than coronal & greatest concentration of collagen occurs in the most apical portion of the pulp. This is of practical significance as engaging the pulp with a barbed broach in the apex region affords a better oppurtunity to remove the tissue intact.

Textbook of endodontics

Undifferentiated mesenchymal cells

• Totiopotent cell• Light microscope – large polyhedral cell ,large

lightly stained centrally placed nucleus.• Decrease in old age – reduces the

regenerative potential of the pulp

orbans

Odontoblasts

• 2nd most prominent• Adjacent to the predentin with cell bodies in the

pulp & processes in the dentinal tubules.• Diameter- 5-7 um• Length – 25-40 um • Cell bodies – large oval nuclei , fills the basal part

of the cell• Adjacent to the nucleus basally, RER & golgi app• Pulpal predentin junction – no organelles

orbans

• Odontoblasts mainly synthesize type I collagen ,proteoglycans & also secretes dentin sialoprotein, alkaline phosphatase , phosphophoryn involved in extracellular mineralization.

Pathways of pulp

• Cell junctions : macula adherens tight junctions gap junctions• More cylindrical & longer – crown• More cuboid – middle of root• Ovoid & spindle shaped – close to apex• Releases IL-8 , chemotactic for neutrophils• Nitric oxide synthetase – vasodilation & blood

pressure regulationBerkowitz

DEFENCE CELLS

• Histiocyte / macrophage –

• Inactive –difficult to distinguish from fibroblasts

• Pulpal inflammation- exhibit granules & vacuoles in their cytoplasm , nuclei increases

• Small blood vessels & capillaries• Aggregate of vesicles or phagosomes

orbans

• Dendritic cells

• Similar to langerhan’s• In deciduous teeth – odontoblasts• Increase in areas affected by caries, attrition

or restorative procedures• Immunocompetent cells in deciduous teeth

increased in number during shedding.

Tencates

• Lymphocytes

• Mast cells – vessels in the inflamed pulp.

• Plasma cells – antibodies light microscope – nucleus

appears small & concentric cart wheel appearance

Orbans

lymphocyte Mast cell

BLOOD VESSELS

• The blood vessels – arise from inferior or superior alveolar artery & drain by same veins

• Small arteries & arterioles – apical canal & pursue a direct route to the coronal pulp. Along their course they give off numerous branches in the radicular pulp that passes peripherally to form plexus in the odontogenic region .

• Pulpal pressure – among the highestTencates

Regeneration of tooth pulp & dentin

LYMPH VESSELS

• Endothelium lined tubes that join thin walled lymph venules or veins in the central pulp.

• Capillaries – thin walls• Central part of the pulp.• Lymph vessel draining the pulp & pdl – common

outlet.• Anterior teeth – submental • Posterior teeth – submandibular & deep cervical

nodes

NERVES

• non-myelinated • 150-1200• Larger fibre range 5 & 13 um, majority are

smaller than 4 um• Perineurium & epineurium – thin• Parietel layer, plexus of rashkow• pulp horns

berkovitz

• The mature deciduous teeth-well innervated, esp coronal pulp , has many nerve endings terminating in or near odontoblast layer , with a few penetrating into dentin.

• No clear evidence that any sensation other than pain can be experienced fron pulp.

• The sensory nerves of the pulp arise from the trigeminal nerve.

Pathways of pulp

Textbook of endodontics

A$ - myelinated faster pulp- dentin junction sharp,pricking, localized

C – sympathetic efferents non myelinated throughout the pulp dull & more diffuse pain

• EPT stimulates A delta fibres first because of their lower threshold. As intensity of stimulus is increased, some of the C fibres also get stimulated.

• The relatively late appearance of A fibres in the pulp may explain why EPT tends to be unreliable in young teeth since A fibres are more easily stimulated than C fibres.

Pathways of pulp

FUNCTIONS

INDUCTIVE

FORMATIVE

NUTRITIVE

PROTECTIVE

DEFENSIVE/REPARATIVE

Tencates

Differences in primary & permanent pulp tissues

• PRIMARY PULP• Function for only about 8yrs & 3 mths

duration• 3 time periods :

1. Period of growth of pulp organ : in about 1yr time , the crown & roots of the

teeth develop

orbans

2. Period of maturation of pulp: root is completed & resorption of root

begins at about 3yrs to 9 mths of age3. Regression of pulp : period of regression of deciduous radicular

pulp depends on the time from the completion of the permanent crown till the time of permanent tooth eruption.

• Max. life of primary pulp organ : 9yrs & 6mths.

orbans

• PERMANENT PULP ORGAN• The pulp undergoes development for about

12 yrs ,4mths.( crown calcification to root completion )

• Primary teeth – 4yrs, 2mths• Period of pulp aging is much accelerated in

primary teeth.• Maxillary arches require slightly longer to

complete each process of development.

orbans

AGE CHANGES

• Most conspicuous change – decreasing volume of the pulp chamber & root canal

• In old teeth , RC is often a thin channel. sometimes almost completely

obliterated.• Continued restriction in pulp volume –

decrease in vascular supply & initiates other age changes.

orbans

• Cell changes

• Reduction in size & no. of cytoplasmic organelles.

• 20 yrs of age , cells gradually reduce in no. until age 70 ,cell density has decreased by

about half.

orbans

Fibrosis

• Radicular pulp – arranged longitudnally in bundles

• Coronal pulp – random/diffuse• Any external trauma – localized fibrosis or

scarring effect.• Collagen increase is noted in media &

adventitia layer of blood vessel

Vascular changes

• Reduced vascularity• Blood flow is decreased.• Calcification in the walls of blood vessels –

near apical foramen• Atherosclerotic plaques may appear

Tencates

Pulp stones

• Denticles• Calcified masses appearing in either or both

the coronal & root portions of the pulp organ• Usually are asymptomatic, unless impinge on

nerve or blood vessel.

• CLASSIFICATION

• Acc to structure : true false

• Acc to relation with Dentin : free attached embedded

Textbook of endodontics

True

• Similar to dentin• Close to the apical foramen• Development – inclusion of remnants of HERS within the pulp. they induce the cells of the pulp to differentiate into odontoblasts which form the dentin masses.

Tencates

False

• Appear as concentric layers of calcified tissues• They appear within a bundle of collagen

fibres.• Some arise around vessels.• In the centre – remnants of necrotic &

calcified cells.• Phlebolith – may serve as nidi for false

denticles.

Tencates

• Free – • Attached-• Embedded-

• 90% - > 50yrs of age • 80% - 30-50 yrs of age • 66% - 10-30 yrs of age

Tencates

Diffuse calcification

• Irregular calcific deposits in the pulp tissue usually following collagenous fibre bundles or blood vessels.

• usually found in the root canal , whereas denticles are more in coronal pulp.

orbans

CLASSIFICATION

• Acc to Grossman:1. Pulpitis a) Reversible symptomatic asymptomaticb) Irreversible o acute responsive to cold responsive to heat

Textbook of endodontics

o chronic Asymptomatic hyperplastic pulpitis internal resorption

2. Pulp degenerationa) calcificb) Others necrosis

WHO Classification

• K04.4 – AAP• K04.5 – CAP• K04.6 – PA with sinus• K04.60 – PA with sinus to max antrum• K04.61 - PA with sinus to nasal cavity• K04.62- PA with sinus to oral cavity• K04.63 - PA with sinus to skin• K04.7 - PA without sinus• K04.8 - PC• K04.80 - apical & lateral cyst • K04.81 - Residual cyst• K04.82 - inflammatory paradental cystPathways of pulp

Ingle’s Classification

A. Painful Pulpoperiapical Pathologies 1. AAP 2. Advanced AP a. Acute Apical Abscess b. phoenix abscess c. suppurative apical periodontitis

B. Non – Painful 1. Condensing osteitis 2. CAP - incipient stage 3. CAP - Periapical granuloma - periapical cyst - suppurative apical periodontitis

Acute Apical Periodontitis

Acute Apical Abscess

Phoenix Abscess

• An acute inflammatory reaction superimposed on an existing chronic lesion, such as cyst or granuloma.

Periapical Granuloma

Radicular Cyst

External Root Resorption

Internal Resorption

Pulp Necrosis

• Effect of posture on pulpal flow

In normal upright posture , there is less pressure effect in the structure of head. Lying down increases blood flow to pulp by removal of both gravitational & baroreceptor effect.

Textbook of endodontics

• Regeneration of pulp dentin

Regeneration of tooth pulp & dentin

conclusion

References

• Orban’s Oral Histology &Embryology- 12th ed• Pathways of the pulp –stephen Cohen 9th ed• Textbook of endodontics – Nisha garg & Amit garg• Oral histology –Tencates• Berkovitz • Regeneration of tooth pulp and dentin : trends

and advances. Sarang Sharma, Vimal Sikri.Annals of Neurosciences, Volume 17, Number 1, January 2010