effect of endodontic treatment procedures on canal shape

8/19/2019 Effect of Endodontic Treatment Procedures on Canal Shape

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Efect o EndodonticTreatment Procedures onCanal Shape and MechanicalProperties o a Tooth



1. Introduction

• ETPs induce changes in tooth structure and mayshift stress distriubutions in treated tooth thatmake them more prone to racture.

• Mechanicalproperties

• Dentincharacteristics

• Shape of the rootcanal

• Moisture• Irrigants• Medicaments•

Obturationmaterials

• Temperature rise• Canal taper



2. Mechanical and StructuralCharacteristics o Root Dentin

Enamel

• igh mineral content → high elastic modulus andlo! tensile strength → hard but bristtle

•

Mechanical properties of enamel are dependenton the type and direction o" the stress applied# as!ell as on the enamel prisms orientation.




Dentinenamel !unction "DE#$

• $ biological interface

• Dissipate stress and inhibit further crack

propagation• as high fracture toughness

→ DE% along !ith the more resilient underlyingdentin supports the integrity o" the enamel bypre&enting fracture during function




Dentin

• Microstructure' Tubules are prominent featuresand radiate out!ard from the pulp to the DE% inthe corocal detin and from the pulp in the rootcanal to the cementum in the root.

• ydrated biological composite !ith properties andstructural that &ary !ith the location !ithin thetooth.

• The colla%en phase of dentin contributes to alo!er elastic modulus campared to that of theenamel.

• The lo&er mineral content of the dentin is also

associated !ith a lo!er hardness.




Dentin "cont.$

• The relati&e contribution of tubules# peritubulardentin and intertubular dentin &aries signi(cantlyin composition !ith location → profound e"ectson the dentin)s tensile strength.

• The ultimate tensiles strength of the dentin &aries!idely and is dependent on intra*tooth locationand depth.• The dentinal tubules is surrounded by minerali+ed

collagen (brils ogani+ed layer by layer on planestran&erse to the tubules

→ igher ultimate tensile strengths !hen a tensile force!as directed perpendicular to tubule orientation




Dentin "cont.$

• Masticatory loads → stresses and strains

• The s'ner%ism of the enamel# coronal dentin# and rootdentin creates an integrated organ that is capble of

supporting high masticatory stresses.• The root dentin is an important component in this

structure to integrate the dentition !ith muscle*bonesupport.

• uman root dentin has hi%her (e)ural stren%th and

more signi(cant inelastic deformation than coronal dentin.→ ,hen tooth cro!n is structurally compromised# a -CTmay be necessary to maintain tooth integrity and to pro&idestability for coronal rehabilitation.

effect of endodontic treatment procedures on canal shape

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