Restoration of

Restoration of

endodontically treated tooth

Amalgam, resin

composite, and glass

ionomer

in combination with

a prefabricated

post

Amalgam

had the lowest

failure rate,

Glass

ionomer

core buildup materials

caused the

greatest number of

failures

R. E.

Kovarik

, L. C. Breeding, and W. F.

Caughman

, “

Fatigue life

of three core materials under simulated chewing conditions

,” The

Journal of Prosthetic Dentistry, vol. 68, no. 4,

pp. 584–590

, 1992

Some studies

supported the

use of amalgam dowels in the root

canals

Tamse

compared 49 mesial roots extracted due to

vertical fractures

with 52 mesial mandibular roots without

fractures,

and

found that 67.3% of the

vertically fractured

roots

had an

amalgam dowel

in the

coronal

part (1-2mm) of

the root

.

In another

study,

endodontically

treated teeth not crowned after

obturation

were

lost 6 times more often than teeth crowned

after

obturation

S. A.

Aquilino

and D. J.

Caplan

, “Relationship between

crown placement

and the survival of

endodontically

treated teeth

,”

The

Journal of Prosthetic Dentistry

, vol. 87, no. 3, pp.

256–263, 2002

.

A 10-year prospective clinical trial,

showed 94

% survival rate of metal post-and-cores with a

crown

G.

Heydecke

andM

. C. Peters, “The restoration of

endodontically

treated

, single-rooted teeth with cast or direct posts

and cores

: a systematic review,”

The Journal of Prosthetic

Dentistry

, vol

. 87, no. 4, pp. 380–386, 2002.

Another 17-year controlled prospective study

showed that

the type of core restorations under the crowns

had no

effect on the survival rate of 307

endodontically

treated

teeth

W. A.

Fokkinga

, C. M.

Kreulen

, E. M.

Bronkhorst

, and N.

H. J

.

Creugers

, “Up to 17-year controlled clinical study on

postand

- cores

and covering crowns,”

Journal of Dentistry

, vol.

35, no

. 10, pp. 778–786, 2007.

Post-core

The use of

posts

does not reinforce

endodontically

treated teeth

and some

reports even show that teeth which were

restored without

a post and core are less susceptible to fracture

than teeth

with post and

core

A.

Smidt

and E.

Venezia

, “Techniques for immediate

core buildup

of

endodontically

treated teeth,” Quintessence

International, vol

. 34, no. 4, pp. 258–268, 2003

Post-core

Its success relies on the success of the entire system and vice versa.

For anterior restorations, consider using a ceramic or light-colored fiber post made of quartz, silicone or glass fibers.

Post Shape

Posts come in three basic shapes: parallel, tapered, and parallel-tapered

Parallel

Parallel posts are more retentive than tapered ones.

They seem

less

likely to cause

root fractures

, distributing stresses evenly along their length.

However, parallel posts require removal of more tooth structure than tapered ones and, therefore, may not be suitable for roots with thin walls.

Tapered

Tapered posts allow for minimal dentin removal since most roots themselves are tapered.

The stresses absorbed by these posts are concentrated in the apex

Creating a wedging effect and increasing the risk of vertical root fracture.

Because of this increased risk when tapered posts fail, they are more likely to leave the tooth

unrestorable

.

Parallel-tapered

Advantages of both designs with few reported disadvantages.

This post has a parallel shaft, tapering at the apical end.

This mix achieves retention associated with parallel sides, while allowing tooth preservation at the apex.

Length and Diameter

Post retention improves with increases in post length, rather than diameter.

An increase in post length with a minimum diameter preserves tooth structure and reduces shear stresses and risk of fracture.

Diameter is important for strength and resistance to post fracture

Sequential

use of post twist drills, starting with narrowest and working up to the desired post diameter, can be useful in minimizing tooth loss during post-space preparation.[

Rotational resistance in an extensively damaged tooth can

be obtained

by preparing a small groove in the root canal. This must be in the path of placement of the post and core.

The groove is

normally located

where the root is bulkiest, usually on

its lingual

aspect.

Influence of post and cores on light transmission through all-ceramic crowns

Some ceramic systems are semi-translucent (IPS Empress®,

Ivoclar

Vivadent

)

Others

are semi-opaque (In-Ceram®,

Vident

, Brea, CA

).

A traditional metal post (gold or titanium) results in poor esthetics because of the lack of light transmission.

. Metallic posts also create a light blue/gray appearance at the gingival margin, possibly as a result of shadows.

Metal post

Esthetic

Corrosion reactions

Taste

Oral burning

Oral pain

Sensitization

and other allergic

reactions

Hayashi

Y, Nakamura S. Clinical application of energy

dispersive x-ray microanalysis for nondestructively

confirming dental metal allergens. Oral

Surg

Oral Med

Oral

Pathol

1994; 77: 623-626

Radiopacity

FRC

Postec

shows reduced

radiopacity

Used in conjunction with

Variolink

II provides additional x-ray identification

Removal

FRC

Postec

can be removed with a rotary instrument if retreatment is required

Zirconia posts

Meyenberg

Good

chemical

stability

Mechanical strength

High toughness

Color similar

to that of natural

teeth

Ahmad I. Yttrium–partially stabilized zirconium dioxide

posts: an approach to restoring

coronally

compromised

nonvital

teeth.

Int

J Periodontics

Restor

Dent 1998; 18:

454-465.

Zirconia posts

Nearly

impossible to

remove

Removal

of

zirconia

post by

ultrasonic causes

temperature rise of the post and on the

root surface

Zirconia post

Cormier

et

al:

fracture strength

of zirconia

post varied according to the different stages

of tooth

restoration.

When

the post alone was

bonded into

tooth, fracture strength was 101.5 N

;

when

the post

was bonded into tooth with core buildup,

fracture strength

was 179.7 N

;

with post and core buildup

as well

as full veneer restoration, fracture strength

was 238.8 N

Cormier CJ, Burns DR, Moon P. In vitro comparison of

the fracture

resistance and failure mode of fiber, ceramic

and conventional

post systems at various stages of

restoration. J

Prosthodont

2001; 10: 26-36.

The

bond strengths

of luting agents to zirconia posts

were measured

without bonding to any tooth structure,

and it

was shown that a dual-cured resin

cement

,

Panavia

(Kuraray

, Osaka), produced

better results

than

other cement types

Sahmali

S,

Demirel

F,

Saygili

G. Comparison of in

vitro tensile

bond strengths of luting cements to metallic

and tooth-colored

posts.

Int

J Periodontics

Restor

Dent

2004; 24

: 256-263.

The

reviewed studies

suggested that

FRC

and

zirconia

posts might be the

preferred

clinical

choice for preventing coronal

microleakage

Jung SH, Min KS, Chang HS, Park SD, Kwon SN,

Bae

JM.

Microleakage

and fracture patterns of teeth restored

with different

posts under dynamic loading. J

Prosthet

Dent 2007

; 98:

270-276

Reid LC,

Kazemi

RB,

Meiers

JC. Effect of fatigue

testing on

core integrity and post

microleakage

of teeth

restore with

different post systems. J

Endod

2003; 29:

125-131

Usumez

A,

Cobankara

FK,

Ozturk

N,

Eskitascioglu

G,

Belli S

.

Microleakage

of

endodontically

treated teeth

with

different dowel systems. J Prosthet Dent 2004; 92: 163-169

zirconia

posts showed the

highest

radiodensity

level, followed by metallic posts,

carbon fiber

posts, glass fiber posts, and carbon fiber

post covered

with quartz fiber.

In a

study by

Dietschi

et

al.

It was

reported that

the

carbon

fiber post

presented the

lowest marginal

gap

proportion

(7.11%) compared to other post types which

presented

higher degrees of marginal gap formation:

titanium post at 11%, zirconia post at 16.5%, and

stainless steel post at 17.4

%

Dietschi

D,

Ardu

S,

Rossier

-Gerber A,

Krejci

I.

Adaptation of

adhesive post and cores to dentin after in vitro

occlusal

loading

: evaluation of post material influence. J

Adhes

Dent

2006; 8: 409-419

.

A)

a flame heated

endo

plugger

,

B)

GatesGlidden

drills

C

)

GPX drills

sixty-six extracted maxillary

central

Removed

from

CEJ

Ah26

Six teeth were used as positive and negative

control

other sixty teeth were divided

into 3

groups, each group containing 20

teeth

apical dye leakage in each group was measured by

astereomicroscope

Minimal

mean dye

leakage was

related to the hot

plugger

group

Maximum mean

leakage was observed in Gates

glidden

drill group

Kwan and

Harrington (1981

) and Madison and

Zakariasen

(1984) found

that post

space preparation with Gates Glidden

drills immediately

after

obturation

actually

decreased the amount

of apical leakage.

Flame-heatedendo pluggers

Fast

Inexpensive

don‘t

cause canal shape

alterations

Burn

potential

for the

dentist, dental assistant or the

patient

did not cause any permanent damage to the

periodontium

Peeso reamers

Very fast

Creates

parallel walls which

provide optimal

retention form for the

post

possiblity

of creating

root perforation

, canal transportation,

overenlargement

of

the canal

Only in

straight canals

The

gates

glidden

drills are more conservative instruments

compared with

Peeso

reamers drills

GPX

match standardized

endothontic

file

sizes # 25 #50

.

Slight

frictional heat

which softens

the GP before

removal

Fast

and

effective

The

bur does

not engage the dentin so canal shape

remains unaltered

and the frictional heat generated is minimal