Apexification

By

Ahmad mostafa hussein

Demonstrator, Department of Dental Biomaterials

Faculty of Dentistry, Mansoura university

2012

Introduction

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 apex

What is the treatment of:

•Reversible pulpitis

•Irreversible pulpitis or necrotic pulp

?

* Treatment of reversible pulpitis: apexogenesis Note: Shallow pulpotomy has higher success rate than conventional pulpotomy.

* Treatment of irreversible pulpitis or necrotic pulp: - apexification (contraindication: very short roots and thin walls).- root canal treatment & surgery (contraindication: very short roots and thin walls).- extraction (if very poor prognosis).

In case of immature open apex

How can we differentiate between:

• Normal radiolucency surrounding immature open apex

• Pathologic radiolucency resulting from a necrotic pulp

?

To differentiate between normal and pathologic

radiolucency

Comparison with the periapex of the

contralateral tooth is helpful, with the other

diagnostic 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)2

1. Advantages

2. Serious disadvantages

3. Mineralization induced by Ca(OH)2 is

affected by …………………………....

…………………………...

Ca(OH)2

Advantages1) alkaline pH

2) bactericidal

3) stimulate apical calcification.Note: The reaction of periapical tissues to Ca(OH)2 is

similar to that of pulp tissue. Ca(OH)2 produces a multilayered sterile necrosis

permitting subjacent mineralization.

Ca(OH)2Serious disadvantages1)long treatment period, usually takes 6-9 months, & 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 teeth fracture.

Ca(OH)2

Mechanism 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% bismuth oxide, 5% gypsum; lime (CaO), silica (SiO2) & bismuth oxide (Bi2O3) are the 3 main oxides in the cement.

* Portland cement is the major constituent. It is responsible for the setting & biologic properties.

* Bismuth oxide provides radiopacity.

* Gypsum is an important determinant of setting time.

* Portland cement is composed of 4 major components; tricalcium silicate, dicalcium silicate, tricalcium aluminate, & tetracalcium aluminoferrite.

* Tricalcium silicate is the most important constituent of Portland cement. It is the major component in the formation of calcium silicate hydrate which gives early strength to Portland cement.

* Dicalcium silicate hydrates more slowly than tricalcium silicate & is responsiple for the latter’s strength.

* Aluminoferrite (contains iron) is present in gray MTA. It is responsible for the gray discoloration. It may discolor the tooth.

Types of MTAGray MTA (GMTA) White MTA (WMTA)

1. Contains aluminoferrite (contains iron), which is responsible for the gray

discoloration. It discolors both the tooth & gingival tissue close to the repaired root surface.

1. Tooth-colored, due to lower amounts of

Fe2O3.

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 hydroxyapatite crystals than WMTA in an environment with PBS (phosphate- buffered saline).

4.

5. Induced dentin formation more efficiently; high number of dentin bridge formation (reparative dentin).

5.

MTAReaction & formation of hydroxyapatite* Hydration reaction.

* Notes: - MTA is called hydraulic silicate cement (HSC). - It is called hydraulic cement ( تحت صالبة مكتسب (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 supplied sterile water in a powder to liquid ratio of 3:1 according to the manufacturer’s instruction.Note: Poor handling properties. The loose sandy nature of the mixture causes much difficulty for the insertion & packing of MTA. Insertion: Ultrasonic-assisted condensation [the ultrasonic vibration applied to endodontic plugger(condenser)] is more 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.