2The PulpIt is a specialized loose connective tissue occupying a cavity in the dentine. It is a remnant of the embryologic organ for tooth development.It has an ectomesenchymal origin.
3The PulpAt first the pulp is called dental papilla; which is highly vascular; and its cells develop into fibroblasts and odontoblasts.After dentin formation this tissue is called dental pulp.dental papilla
4Both dentin and pulp have a common origin from the dental papilla.
5Anatomy of PulpPulp horns or cornuaPulp Chamber or coronal pulp, located in the crown of the tooth.Root canal or radicular pulp, is the portion of the pulp located in the root area.The apical foramen is the opening from the pulp at the apex of the tooth to be continuous with the periapical tissue .Accessory canals or lateral canal, extra canal located on the lateral portions of the root.
6The coronal pulpIt is called pulp chamber, where in young teeth it is large and have the shape of the D.E.J.The pulp chamber has pulp horn (s) according to the number of the cusps.Pulp horns
7The radicular pulpIn anterior teeth it is single, in posterior teeth it is multiple.Its shape conforms to the D.C.J.Apically the root canal opens to the periodontal ligament by apical foramen.Pulp hornsRoot canals
8The apical foramenThe pulp organs are continuous with the periapical tissue through the apical foramen.The average size of the apical foramen is:maxillary teeth: 0,4 mmmandibular teeth: 0,3 mmapical foramen
9The apical foramenAs the root begins to develop, the apical foramen is actually larger than the pulp chamber, but it becomes more constricted at the completion of root formation.
10Accessory canalsAcc. canalThe pulp cavity is sometimes connected with the periodontal tissue with an opening rather than the apical foramen, the lateral, accessory or supplementary canal.pulpPDL
11Accessory canalsThey are numerous in the apical third of the root and in the bifurcation of multirooted teeth.If the root canal breaks up into multiple tiny canals, it is referred to as a delta system because of its complexity.
13Etiology of accessory canals Degeneration of the epithelial root sheath of Hertwig before odontoblasts differentiation.Large blood vessel disturbs the course of the root sheath.Lack of union of the tongue like projection (in multi-rooted teeth).
23Cell free zone (Weil zone) It is about 40 micron thick.It is prominent in the coronal pulp and less prominent in the radicular pulp.Cell free zoneIt contains few cells.In the zone many processes of the fibroblasts of the cell rich zone, nerves and blood vessels are observed.
24Cell free zone (Weil zone) OdobtoblastsBlood vesselNerves
31Cells of the pulp Progenitor cells (UMC) Synthetic cells Odontoblasts FibroblastsDefensive cellsHistocytesLymphocytesMast cellsPlasma cells
32Progenitor cells (UMC) They are also called Reserve Cells.They are descendants of undifferentiated cells in the primitive dental papilla.They are multipotential cells and likely a ﬁbroblast type.They are found along the blood vesselsThey retain the capability ofdedifferentiating on demand intomany of the mature cell types.
33Odontoblasts tomes fiber predentin They line the pulpal surface of dentinA layer of predentin is always present between them and dentin.Each odontoblast has a cell body (perikaryon) and a protoplasmic process (tomes fiber)tomes fiberpredentinperikaryon
34Odontoblasts The odontoblasts are arranged in a single layer where: In the pulp chamber the cells are crowded and appear psudostratefied columnar.Near the beginning of the root canal they become columnar in shape.
35OdontoblastsIn the mid portion of the root canal they become cuboidal in shape.In the apical area of the root canal they become flat cells.
36Fibroblasts They are star like cells with ovoid nucleus. The greatest number in the dental pulp, particularly in the cell rich zone.Their function is to form and maintain the pulp matrix.They also eliminate excess collagen
37Defensive cells Histocytes and macrophages : Large oval or spindle shapedThe cytoplasm is granular, especially during inflammationHave large lysosomesMain function is to eliminatedead cells.
38Defensive cells Lymphocytes and plasma cells: These cells are not normally present in healthy pulp tissue but are associated with injury and resultant immune responses attempts to destroy, damage, or neutralize foreign substance.These inﬂammatory cell types generally appear following invasion into the area of injury.
39Defensive cellsTheir presence would therefore indicate the presence of a persistent irritant.plasma cellsLymphocyte
40Defensive cells Plasma cells produce antibodies. The nucleus is eccentric with cart wheel appearance.plasma cell
41Defensive cells Mast cells: Mast cells are seldom in large numbers in normal, healthy pulps, but are commonly found in inﬂamed pulps.Have granular cytoplasm with round nucleus.
42Defensive cellsThe granules of these cells contain histamine, a potent inﬂammatory mediator, and heparin.These cells release these granules or degranulate into the surrounding tissue ﬂuid during inﬂammation.
43Matrix and ground substance The extracellular compartment (matrix) is a structureless mass, gel-like in consistency and consists of collagen fibers and ground substance.The ground substances resembles that of other loose connective tissue.It consists of acid mucopolysaccharides, neutral glycoprotein and water.It acts as a medium for the transport of nutrients.
44Matrix and ground substance These ﬁbers form a loose, reticular network to support other structural elements of the pulp.Collagen is synthesized and secreted by odontoblasts and ﬁbroblasts.However, the type of collagen secreted by odontoblasts to subsequently mineralize differs from the collagen produced by pulpal ﬁbroblasts, which normally does not calcify.
45Matrix and ground substance The collagen fibers are particularly type I and type III collagen.In young pulps there are single fibers scattered between the cells. As age change the pulp become fibrilar.The greatest concentration of collagen fibers occurs in the most apical portion of the pulp.
46Matrix and ground substance The bundles of collagen at the pulp periphery are termed von Korff’s ﬁbers.They are corkscrew-like and originating between odontoblasts to pass into the dentin matrix.