Dynamics of Dental Pulp & Periapical Pathologies Deepti Awasthi P 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

Regeneration of tooth pulp dentin 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

location & shape may undergo changes 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

Textbook of Endodontics – Nisha Garg 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

Inflammation & healing Fibres – type I & III length – 10 – 100nm 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

Textbook of endodontics 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

More cylindrical & longer – crown More cuboid – middle of root 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 regulation Berkowitz

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

Similar to langerhan’s In deciduous teeth – odontoblasts 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

Mast cells – vessels in the inflamed pulp. Plasma cells – antibodies 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 highest Tencates

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 sensory nerves of the pulp arise from the trigeminal nerve. 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 Textbook of endodontics

EPT stimulates A delta fibres first because of their lower threshold 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 Tencates INDUCTIVE FORMATIVE NUTRITIVE PROTECTIVE REPARATIVE DEFENSIVE/ Tencates

Differences in primary & permanent pulp tissues PRIMARY PULP Function for only about 8yrs & 3 mths duration 3 time periods : 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 age 3. 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

Primary teeth – 4yrs, 2mths 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

Reduction in size & no. of cytoplasmic organelles. 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.

Textbook of endodontics 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 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

Textbook of endodontics CLASSIFICATION Acc to Grossman: Pulpitis Reversible symptomatic asymptomatic Irreversible acute responsive to cold responsive to heat Textbook of endodontics

chronic Asymptomatic hyperplastic pulpitis internal resorption Pulp degeneration calcific 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 cyst Pathways of pulp

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

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

Textbook of endodontics 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 tooth pulp & dentin 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