Mentoring UKGDI HISTOLOGI

Mentoring UKGDIHISTOLOGIErlina Sih Mahanani, drg, M.KesPrgram Study Kedokteran GigiFakultas Kedokteran dan Ilmu KesehatanUniversitas Muhammadiyah YogyakartaOral Mucous MembraneIs the moist lining in the oral cavityOral cavity consists of 2 parts:Outer vestibule ( lips and Cheeks)Oral cavity proper Superior zone (hard & soft palates)Floor zone (tongue)Posterior zoneOral mucous membrane

Types of dentinPrimary dentin: is formed in a tooth before the completion of the apical foramen of the root. Mantle dentin: the first predentin that forms and matures within the tooth.Circumpulpal dentin: the layer of dentin around the outer pulpal wall.

Erlina S M, Dentin & Pulp

5Secondary dentin: is formed after the completion of the apical foramen and continues to form throughout the life of the tooth.Tertiary dentin: is formed in response to an external stimuli. Predentin: is newly deposited unmineralized dentin.

Erlina S M, Dentin & Pulp

6Erlina Sih MahananiTypes of DentinDentinSecondary physiologic dentinTertiary dentin orReparative dentin orReactive dentin orResponse dentinMantle dentinCircumpulpal dentinPeritubular dentinIntertubular dentinPrimary physiology dentin7Erlina Sih Mahanani

PrimaryphysiologicaldentinSecondaryphysiologicaldentin8Erlina S M, Dentin & PulpIntertubular & Peritubular/Intratubular

Peritubular is the dentinal matrix that immediately surrounds the dentinal tubule.It is called Peritubular cause it is hyper mineralized collar surrounding the tubules.Peritubular is present in tubule throughout dentin except near the pulp.

9Erlina S M, Dentin & PulpDentinal tubules & Odontoblast process

ABSEM of Predentin

CDSEM of Dentin

10Erlina S M, Dentin & PulpOdontoblast Process

Odontoblast processes (Odp) run in canalicules called dentinal tubules.11Erlina Sih Mahanani

Dentinal tubules

Dentinal matrix

Intertubular dentin

12Erlina S M, Dentin & PulpLines in dentinIncremental linesis deposited incrementally, a hesitation in activity follows.This hesitation in formation results in alteration of matrix It also can be called lines of von EbnerNeonatal lineIt is hypocalcified area represented by a wide contour line in the teeth.These are found in deciduous teeth and first permanent molar.It represents the disturbance in mineralization due the abrupt change in environment that occurs at birth.

Neonatal line13Dentin Pulp ComplexErlina Sih Mahanani

DentinPredentinOdontoblasts layerCell free zoneCell rich zonePulp core15Erlina Sih Mahanani

Odontoblast and ProcessOdontoblast processOdontoblast cells16Erlina Sih MahananiOdontoblast and Process

PredentinDentinErlina Sih Mahanani

The size, curvature and distance between tubules in outer, mid, and inner surface of dentinThe dentinal tubules are sigmoid (S) shape curved structure which run perpendicularly from the pulp toward the periphery.Near the root tip, incisal edge and cusps, are almost straight. The tubules are approximately 1 micron in diameter at their outer end, 1.5 at mid, 1.5 3 near the pulp.The number of dentinal tubules at the pulp end is nearly 4-5 times more than at outer surface.

Cavity Preparation18Erlina Sih Mahanani

Cavity PreparationThe number of dentinal tubules near the pulp end is 4-5 times more than at outer surface.

19Erlina Sih MahananiThe dentin formed in response to caries, abrasion, erosion, attrition, or operative procedures is known as reparative, tertiary, reactive or response dentin.These cause the odontoblasts to be cut or injureddegeneration of a large number of odontoblast.The odontoblast that are killed are replaced by the movement of undifferentiated cells from the cell rich zone or from the undifferntiated perivascular cells present deeper inside the pulp.

Erlina Sih Mahanani

EnamelRestorationDead tractSclerosed dentinal tubulesReparative dentinReparative DentinErlina Sih MahananiReparative DentinThe process of response dentin is started by the pulp.It helps seal off the area of injury causing resolution of inflammation & removal of dead cells.Reparative dentin has lesser & more twist tubules than normal dentin.In some cases, a combination of osteodentin & tubular dentin is also seen.The quality and quantity is related to the intensity & the duration of stimulus.There is no continuity between dentinal tubules of reparative dentin and overlying primary & secondary dentin. There is the minimize dentin permeability at the side deposition thus giving the protection.Erlina Sih Mahanani

Dental cariesSclerotic dentin23Erlina Sih MahananiSclerotic or Transparent DentinSclerotic dentin is generally observed in the elderly people.Mineral density is greater in this area.It can be present under slowly progressing caries.Sclerosis may help to prolong pulp vitality and reduce dentin permeability.It appears dark in reflected light, and transparent in transmitted light.Erlina Sih MahananiSclerotic or Transparent DentinThe excessive formation of collagen fibers and apatite crystal in dentinal tubules can lead to complete obliteration of dentinal tubulesa defensive reaction of dentin.Initially the apatite crystal s are only sporadic but gradually a fine meshwork.Gradually, the tubule lumen is obliterated with mineral, which appears like quite the peritubular dentin.