Apexification Ahmadmostafa 130301161342 Phpapp02

8/11/2019 Apexification Ahmadmostafa 130301161342 Phpapp02

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ApexificationBy

Ahmad Mostafa Hussein

Demonstrator, Department of Dental Biomaterials, B.D.S. (2004), Master (2012)

Faculty of Dentistry, Mansoura University

10/4/2012

Main points:

Introducton: * Apexogenesis: definition, the materials used.

* Apexification: definition, the materials used.

* Open apex: what is the treatment if reversible pulpitis?

and what is the treatment if irreversible pulpitis or necrotic pulp?

* Precautions during diagnosis.

Apexification

The factors most responsible for apical closure

Causes of failure

Ca(OH)2: 1)advantages, 2)disadvantages,

3)mechanism of mineralization induced by Ca(OH)2

MTA: 1)advantages, 2)disadvantages, 3)uses,

4)composition and compositional differences with Portland cement,

5)types of MTA and differences between gray MTA and white MTA.

6)reaction and formation of hydroxyapatite.

7) a)manipulation: * mixing

* insertion and ultrasonic vibration

* thickness

* X-ray

* moist cotton pellet

7) b) obturation and permanent restoration:

* gatta-percha.

* composite resin restoration extending below cervical level of the tooth.

Note:The post role in reinforcing the immature root remains unclear.

References


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Introduction

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.

Open apex:

* Immature root, short root, thin walls, high risk of root fracture.

* Normally, apical closure occurs approximately 3 years after eruption.

* 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).


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Precautions dur ing diagnosis:

* The apex appears more open when seen from the proximal. Conventional radiograph may

result in selection of inappropriate routine root canal treatment when apexogenesis or

apexification is indicated. Angled radiograph is helpful for diagnosis of open apex.

* Sometimes, it is difficult to differentiate between:

- normal radiolucency surrounding the immature open apex.

- pathologic radiolucency resulting from a necrotic pulp.

Comparison with the periapex of the contralateral tooth is helpful, with the other

diagnostic tests.


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Apexification

* Root-end closure.

* It is the induction of a calcific barrier across an open apex.

* Apexification involves cleaning & shaping, followed by placement of Ca(OH)2or MTA

to the apex.

* The factors most responsible for apical closure are thorough dbridement & coronal seal.

* Causes of failure: bacterial contamination.

Ca(OH)2(calcium hydroxide)

Advantages:1) alkaline pH, 2) bactericidal,

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

Ca(OH)2 produces a multilayered sterile necrosis permitting subjacent mineralization

Serious disadvantages:

1) long treatment period, usually takes 6-9 months, & may extend up to 21 months.

2) possible recontamination may occur.

3) weaken the root dentin & the risk of teeth fracture.4) must be replaced at monthy intervals & removed some months after placement

before final obturation.

5) multiple visits by the patient.

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)2was higher at pH 7.4 than at pH 8.5. Mineralizatio

activity was higher under neutral conditions.


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MTA (mineral trioxide aggregate)

1. Advantages:

1) High success rate. It is the material of choice for apexification & apexogenesis.

2) Excellent biocompatibility.

3) Excellent sealing ability.

4) Save treatment time.

5) More radiopaque than Ca(OH)2.

6) Alkaline pH, which may impart antibacterial effect on some facultative bacteria.

7) Produces an artificial barrier, against which an obturating material can be

condensed.

8) Hardens (sets) in the presence of moisture.

9) Can induce formation (regeneration) of dentin, cementum, bone & periodontal

ligament.

10) Appropriate mechanical properties.

11) Vasoconstrictive. This could be beneficial for hemostasis (most importantly in

pulp capping).

2. Disadvantages:

1) Long setting time (2-4 h after mixing).

2) Poor handling properties. The loose sandy nature of the mixture causes much

difficulty for the insertion & packing of MTA.

3) High cost.

3. Uses:

1) Apexogenesis, direct pulp capping and pulpotomy.

2) Apexification, and root-end filling.

3) Repair of root perforations.

4) Repair of internal and external resorption.


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4.1. Composition:

* 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) arethe 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.

* Portl and cementis 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 latters strength.

* Aluminoferrite (contains iron) is present in gray MTA. It is responsible for

the gray discoloration. It may discolor the tooth.


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4.2. Compositional dif ferences between MTA & Portl and cement:

MTA Portland cement

1. Less amount of gypsum (approximately

half that in Portland cement) which leads

to longer setting time.

1.

2. No toxic impurities 2. May contain toxic impurities.

3. Higher compressive strength &

microhardness values.

3.

4. Less soluble. 4.

5. More radiopaque. 5.

6. 6. Not have US Fedral approval for clinical

purposes.

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5. Types of MTA: Gray MTA & White MTA.

* MTA was first described in the dental literature in 1993. When it was first commercialized

it had a gray discoloration (gray MTA). In 2002, white MTA was introduced.

Gray 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. 1. Produces 43% more surface

hydroxyapatite crystals than WMTA in

an environment with PBS (phosphate-

buffered saline).

4.1.

4.2. Induced dentin formation more

efficiently; high number of dentin bridge

formation (reparative dentin).

4.2.

5. Increase in acidity or alkalinity beyond 8.4 can deleteriously affect the surface hardness o

set MTA.

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6. Reaction & formation of hydroxyapatite:

* Hydration reaction.

* Note:- MTA is called hydraulic silicate cement (HSC).

- It is called hydraulic cement (

) (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).

7.1. Manipulation , 7.2. Obturation & permanent restoration:

1. M ixing: gray MTA & white MTA are mixed with supplied sterile water in a powder to

liquid ratio of 3:1 according to the manufacturers instruction.

Note:Poor handling properties. The loose sandy nature of the mixture causes

much difficulty for the insertion & packing of MTA.

2. Inserti on: Ultrasonic-assisted condensation [the ultrasonic vibration applied to endodonti

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.

3. Thi ckness: 5-mm MTA apical plug provided better reduction of bacterial leakage (better

microleakage resistance).


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4. A Radiograghis made.

5. A moist (wet) cotton pel letis placed above the MTA (to ensure setting), & a well-sealing

temporary restorationis placed. Note: MTA sets 3-4 h after mixing.

6. 1.The patient is recalled when MTA

has set (at least 24 hours) for obturation& placement

of permanent restoration.

Note: technique for apical barrier detection:based on the tactile sensation felt by the

operator to detect an apical stop. Radiograghs is an adjunct

to the clinical

technique.

6.2. Complete the root canal treatment with gatta-percha& composite resin restoration

extending below the cervical l evel of the toothto strengthen the roots resistance to fracture

Notes

* If a root canal is fully obturated with MTA, re-entry to create space for a post can be very

difficult using just ultrasonic or rotary nickel-titanium instruments, presumably

due to its hardness & strength.

(i.e. root canal obturation with MTA would severely limit retreatment options).

* Composite resin or MTA materials in the root canal may make future endodontic

retreatment difficult, while titanium, ceramic & zirconium posts are problematic to

retrieve

.

* If a post is to be used, a long thin fibre post should be chosen to reduce the stresses that

cause tooth fracture.

* Superior retention of posts has been observed with dual cure resin luting cements.

* The role of posts & luting agents in reinforcing root filled immature anterior teeth

remains unclear.


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References

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ed. Saunders Co

2009. p. 2934.

2. Ingle JI, Bakland LK, Baumgartner JC. Ingles Endodontics 6. 6th

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Canada: BC Decker Inc.; 2008. p. 138399.

3. Asgary S, Ehsani S. MTA resorption and periradicular healing in an open-apex incisor

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4. Cardoso-Silva C, Barbera E, Maroto M, Garca-Godoy F. Clinical study of minera

trioxide aggregate in primary molars. Comparison between gray and white MTAa lon

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5. Darvell BW, Wu RCT. MTAAn hydraulic silicate cement: review update and settin

reaction. Dent mater 2011; 27: 40722.

6. Chala S, Abouqal R, Rida S. Apexification of immature teeth with calcium hydroxide omineral trioxide aggregate: systemic review and meta-analysis. Oral Surg Oral Me

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7. Narita H, Itoh S, Imazato S, Yoshitake F, Ebisu S. An explanation of the mineralizatio

mechanism in osteoblasts induced by calcium hydroxide. Acta Biomaterialia 2010; 6

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8. Wang WH, Wang CY, Shyu YC, Liu CM, Lin FH, Lin CP. Compositional characteristic

and hydration behavior of mineral trioxide aggregates. J Dent Sci 2010; 5(2): 539.

9. Kim US, Shin SJ, Chang SW, Yoo HM, Oh TS, Park DS. In vitro evaluation of bacteria

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apical plug in teeth with wide open apexes: a preliminary study. Oral Surg Oral Me

Oral Pathol Oral Radiol Endod 2009; 107: e52e6.

10. Desai S, Chandler N. The restoration of permanent immature anterior teeth, root fille

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