POST OR NOT TO POST ?

D R . H I C H A M N U A I M IB D S . P G D I P I M P L A N T O L O G YP G D I P R E S T O R AT I V E D E N T I S T R YM C L I N I N O P E R AT I V E A N D E S T H E T I C D E N T I S T R Y

Treatment of Badly Destructive Teeth have huge controversy about the decision of whether or not posts should be used

Restoring of badly destructive pulpless teeth have been reported since 18 centurey.

Pierre Fauchard in 1747 designed gold and silver posts.

Last decades fabricated Carbon posts due to its proper elastic modules and flexture resisitance

Due to upgrade in Esthetic demand, Scientist invest cotted Carbon post then glass and ceramic ones.

HISTORY

Role for post placement IndicationsTypes Procedure

POSTS

The primary purpose for a post is to retain a core that can be used to support the final restoration.

Posts do not reinforce endodontically treated teeth, and a post is not necessary when substantial tooth structure is present after a tooth has been prepared.

Roles for post placement

Post placement is indicated if both of the following clinical conditions exist:The remaining coronal tooth structure is

inadequate for the retention of a restoration.When there is sufficient root length to

accommodate the post while maintaining an adequate apical seal.

Stockton L (1999).Factors affecting retention of post systems: A literature review. J Prosthet Dent;81:380–385.

Indications

Anterior teeth mostly required post, due to the shearing forces and the narrow tooth dimensions.

While Large, bulky anterior teeth with minimal access preparation may not require a post

Molar teeth rarely require a post unless there has been significant loss of tooth structure.

Posts are generally considered necessary for PM teeth because of their smaller diameter and the presence of high shear stresses.

Types of Post

Metallic

Stainless Steel

TitaniumGold-Plated brass

Non Metallic

Carbon Fibre

Ceramic

Composite

Glass-fibre

Stainless steel

Esthetic carbon fiber

Carbon fiber Ceramic

Tapered smooth

Parallel serrated

Parallel threaded

Prefabricated Threaded

Posts

Disdvantages

Stresses generate may

lead to fractureHigh invasive

Advantages

High retention

Carbon Fiber Post

Advantages

Dentin bonding Easy removal

Disdvantages

Low strength esthetic problem

Lack of radiopacity

Fiber Reinforced

Post

Disdvantages

Low strength failure rate

Advantages

Esthetic

Zirconia Ceramic

Disdvantages

High stiffness High modulus of elasticity

Advantages

Esthetic

Rodriques-Cervantes et.al (2007) stated that post must have elastic modules mimic to that of dentine or damage root structure

Tooth structure Elastic modules (Gpa)

Dentin 18.6

Fiber post 20

SS post 200

titanium 110

zirconia 300

Damage to the root

Shear stress

internal

stress

zones of

tension

Post Placement

Post length

Post design

FACTORS

Post diameter

Stockton L (1999). Factors affecting retention of post systems: A literature review. J Prosthet Dent;81:380–385.

Ferrule effect

The post should be > the IC or OC dimension of the crown.

The post should end halfway between the crestal bone and the root apex.

The post should be 2/3 the root length.

Post length

Ideal Placement

✔ ✖

The diameter of the post is selected according to root anatomy.

A minimal dentin thickness of 1 mm around the post should be provided.

Post diameter

Post preparation of the root canal space must not remove additional dentin leads to reduced fracture toughness

NARROW MEDIUM LARGE

Passive action posts lead the lest stress in the root dentine (parrallel, smooth)

Active action post lead the highest stress (threaded)

Post design

Active postsMechanical bend

into dentin by threads

Passive postsDepend on cement

for retention

What is Ferrule Effect

is the circumferential ring of sound tooth structure that is enveloped by the cervical portion of the crown restoration.

A minimum sound dentine height of 1.5 - 2 mm is required between the core and crown margins.

Ferrule Effect

Fernandes et al.(2003) stated that ideal post selection required:

Minimum preparation. Resistance to fatigue. Elastic modulus similar to dentin. Retentive (post & Head). Easy to adjust and fit. Easy Removal

Fernandes A., Shetty Sh., Coutinho I.(2003). Factors determining post selection: A literature Review. J Prosth. Dent. Dec. 2003.

Is it indicated to use a post in all Badly

Destructive Tooth?

Amount of remaining sound tooth structureOcclusal functionOpposing dentitionPosition of the tooth in the archLength, width and curvature of the roots

Endodontics : Restoring of Endodontically Treated Teeth American Association of Endodontics.1995 Dec Publication

Criteria for post placement

LiteraturE ReviewS

Ferrari et.al Fokkinga

SAMPLES240 endodontically-treated premolars in 210patients

307 endodontically-treated teeth in 257patients

TEST TREATMENT

Fiber posts for 2 years Cast post and corePre-fab metal post and composite core for 17 years

CONTROL TREATMENT

No post Post-free composite core

CONCLUSIONS

4 coronal wall remaining: no difference incomplication rates≤ 3 coronal walls remaining: post placementincreases survival rates

Where “substantial remaining dentin” is available, a post and core does not perform better than a post-free core

Ferrari M (2007). Post placement affects survival of endodontically treated premolars. JDentRes;;86(8):729-734.

Fokkinga W.(2007). Up to 17-year controlled clinical study on post-and-cores and covering crowns. J Dent;35(10):778-786.

Salemeh et.al (2007) stated that the fracture loads of teeth restored with fiber posts were significantly greater than those without posts.

The fiber posts significantly contributed to the reinforcement and strengthening of pulpless teeth.

D’Arcangelo et al. (2008) stated that fiber reinforced post restoration with veneer preparations (Max CI) did not show significant differences from the intact unprepared incisor.

Hajizadeh et al. (2009) showed that PM teeth when restored with the Post and composite were as strong as the unprepared tooth and stronger than those teeth restored with composite alone without a post.

Jotkowitz et al. (2010) stated that the height, number of walls remaining, thickness of the walls in addition to ferrule effects on functional stress. They concluded that no ferrule equals un-restorable

Nam et.al (2010) stated that when the number of remaining walls decrease, the fracture resistance decreases, even without post. BUT the fracture resistance is significantly increased when fiber posts are placed.

These huge controversy reviews about fiber post are

due to:

Using of natural teeth or bovine teeth Type and quality of the post Effect of “secondary smear layer” on adhesion Effect of type of radicular dentin that is to be

bonded Types the adhesive used Types of cement used for post placement The amount of critical dentin that is removed to

place the post.

Conclusion  Badly destructive endodontic teeth are weaker,

so that it requires restorations to protect remaining tooth structure.

Ferrule effect is paramount to resist fracture and is more important than post design, material or luting cement.

Clinical success depends on application of sound biomechanical principles for the specific tooth.

More In vivo studies are required to distinguish a clear evidence for using of fiber post

THANK YOU.