What is the difference between: Apexification and apexogenesis ?
Apexogenesis* Vital pulp therapy in an immature tooth to permit continued root growth and apical closure.* Depending on the extent of pulp damage, pulp capping or shallow or conventional pulpotomy may be indicated.* Materials: Ca(OH)2 (calcium hydroxide) or MTA (mineral trioxide aggregate). MTA is the material of choice.
Apexification* Root-end closure.* It is the induction of a calcific barrier across an open apex.* Materials: Ca(OH)2 (has serious disadvantages) or MTA. MTA is the material of choice.
In case of open apexWhat is the treatment of: •Reversible pulpitis •Irreversible pulpitis or necrotic pulp ?
* Treatment of reversible pulpitis: apexogenesis Note: Shallow pulpotomy has higher successrate than conventional pulpotomy.* Treatment of irreversible pulpitis or necroticpulp:- apexification (contraindication: very shortroots and thin walls).- root canal treatment & surgery (contraindication: very short roots and thin walls).- extraction (if very poor prognosis).
In case of immature open apexHow can we differentiate between: • Normal radiolucency surrounding immature open apex • Pathologic radiolucency resulting from a necrotic pulp ?
To differentiate between normal and pathologicradiolucencyComparison with the periapex of thecontralateral tooth is helpful, with the otherdiagnostic tests.
Apexification•Definition•The factors most responsible for apical closure•Causes of failure•The materials used for apexification: * Ca(OH)2 (calcium hydroxide) * MTA (mineral trioxide aggregate) MTA is the material of choice.
Apexification* Root-end closure.* It is the induction of a calcific barrier across an open apex.* The factors most responsible for apical closure are thorough débridement & coronal seal.* Causes of failure: bacterial contamination.* Apexification involves cleaning & shaping, followed by placement of Ca(OH)2 or MTA to the apex.
Ca(OH)21. Advantages2. Serious disadvantages3. Mineralization induced by Ca(OH)2 is affected by ………………………….... …………………………...
Ca(OH)2Advantages1) alkaline pH2) bactericidal3) stimulate apical calcification.Note: The reaction of periapical tissues to Ca(OH)2 issimilar to that of pulp tissue.Ca(OH)2 produces a multilayered sterile necrosispermitting subjacent mineralization.
Ca(OH)2Serious disadvantages1)long treatment period, usually takes 6-9months, & may extend up to 21 months.2)must be replaced at monthy intervals &removed some months after placement before final obturation.3)multiple visits by the patient.4)possible recontamination may occur.5)weaken the root dentin & the risk of teethfracture.
Ca(OH)2Mechanism of mineralization induced by Ca(OH) 2* Calcium ions dissociated from Ca(OH)2 are critical for inducing the mineralization of osteoblasts.* Hydroxyl ions did not have any effect on the mineralization.* The mineralization activity of Ca(OH)2 was higher at pH 7.4 than at pH 8.5. Mineralization activity was higher under neutral conditions.
MTA1.Advantages2.Disadvantages3.Uses4.Composition5.Types (gray MTA & white MTA)6.Formation of hydroxyapatite7.Manipulation(mixing, insertion, thickness, radiograph,moist cotton pellet, temporary restoration) Obturation & permanent restoration
MTAAdvantages1) Save treatment time. High success rate. It is the material of choice for apexification & apexogenesis.2) Alkaline pH, which may impart antibacterial effect on some facultative bacteria.3) Can induce formation (regeneration) of dentin, cementum, bone & periodontal ligament.4) Excellent biocompatibility and appropriate mechanical properties.5) Excellent sealing ability.6) Produces an artificial barrier, against which an obturating material can be condensed.7) Hardens (sets) in the presence of moisture.8) More radiopaque than Ca(OH)2.9) Vasoconstrictive. This could be beneficial for hemostasis (most importantly in pulp capping).
MTADisadvantages1)Long setting time (2-4 h after mixing).2)Poor handling properties. The loose sandy nature of the mixture causes much difficulty for insertion & packing of MTA.3)High cost.
MTAUses1)Apexogenesis, direct pulp capping and pulpotomy.2)Apexification, and root-end filling.3)Repair of root perforations.4)Repair of internal and external resorption.
MTAComposition* MTA is mainly composed of 3 powder ingredients,which are 75% Portland cement, 20% bismuthoxide, 5% gypsum; lime (CaO), silica (SiO2) &bismuth oxide (Bi2O3) are the 3 main oxides in thecement.* Portland cement is the major constituent. It isresponsible for the setting & biologic properties.* Bismuth oxide provides radiopacity.* Gypsum is an important determinant of settingtime.
* Portland cement is composed of 4 major components;tricalcium silicate, dicalcium silicate, tricalciumaluminate, & tetracalcium aluminoferrite.* Tricalcium silicate is the most important constituentof Portland cement. It is the major component in theformation of calcium silicate hydrate which gives earlystrength to Portland cement.* Dicalcium silicate hydrates more slowly thantricalcium silicate & is responsiple for the latter’sstrength.* Aluminoferrite (contains iron) is present in gray MTA.It is responsible for the gray discoloration. It maydiscolor the tooth.
Types of MTA Gray MTA (GMTA) White MTA (WMTA)1. Contains aluminoferrite (contains 1. Tooth-colored, due to lower amounts iron), which is responsible for the gray of Fe2O3. discoloration. It discolors both the tooth & gingival tissue close to the repaired root surface.2. 2. Smaller particles with narrower size distribution (8 times smaller than that of GMTA).3. 3. Greater compressive strength.4. Produces 43% more surface 4. hydroxyapatite crystals than WMTAin an environment with PBS (phosphate- buffered saline).5. Induced dentin formation more 5. efficiently; high number of dentin
MTAReaction & formation of hydroxyapatite* Hydration reaction.* Notes: - MTA is called hydraulic silicate cement (HSC). - It is called hydraulic cement ()مكتسب صلةبة تحت الماء (i.e. sets & is stable under water) relying primarily on hydration reactions for setting. - The material consists primarily of calcium silicate.* When mixed with water, MTA sets. The pH of MTA increases from 10 to 12.5 three hours after mixing. In high pH environment, the calcium ions that are released from MTA react with phosphates in the tissue fluid to form hydroxyapatite (the principal mineral in teeth & bones).
MTAManipulationMixing: gray MTA & white MTA are mixed with suppliedsterile water in a powder to liquid ratio of 3:1 according tothe manufacturer’s instruction.Note: Poor handling properties. The loose sandy nature ofthe mixture causes much difficulty for the insertion &packing of MTA.Insertion: Ultrasonic-assisted condensation [the ultrasonicvibration applied to endodontic plugger(condenser)] ismore efficient than hand condensation in: - the apical flowing of MTA (enable better flow). - delaying bacterial leakage (enable better adaptation). - the production of denser MTA apical plug.
MTA* Thickness: 5-mm MTA apical plug provided reduced microleakage.* A Radiogragh is made.* A moist (wet) cotton pellet is placed above the MTA (to ensure setting), & a well-sealing temporary restoration is placed. Note: MTA sets 3-4 h after mixing.* The patient is recalled when MTA has set (at least 24 hours) for obturation & placement of permanent restoration.
MTA* Complete the root canal treatment with gatta- percha & composite resin restoration extending below the cervical level of the tooth to strengthen the root’s resistance to fracture.
MTANote* The role of posts & luting agents in reinforcing root filled immature anterior teeth remains unclear.
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