RAJIV GANDHI UNIVERSITY OF HEALTH SCIENCESBANGALORE- KARNATAKA

ANNEXURE- IIPROFORMA FOR REGISTRATION OF SUBJECT FOR

DISSERTATION

1. NAME OF THE CANDIDATE AND ADDRESS

DR . SWETHA GOPALPOST GRADUATE STUDENT ,DEPT OF CONSERVATIVE & ENDODONTICS,KRISHNADEVARAYA COLLEGE OF DENTAL SCIENCES , HUNASAMARANAHALLI, VIA - YELAHANKA ,BANGALORE- 562157

2. NAME OF THE INSTITUTION KRISHNADEVARAYA COLLEGE OF DENTAL SCIENCES, YELAHANKA, BANGALORE.

3. COURSE OF STUDY & SUBJECT MASTER OF DENTAL SURGERY IN CONSERVATIVE DENTISTRY & ENDODONTICS

4. DATE OF ADMISSION TO COURSE 3 – 05 - 2010

5. TITLE OF THE TOPIC FRACTURE RESISTANCE OF ENDODONTICALLY TREATED ROOTS RESTORED WITH FIBER POSTS USING DIFFERENT RESIN CEMENTS : AN IN VITRO STUDY

6. BRIEF RESUME OF THE INTENDED WORK

6.1 NEED FOR THE STUDY

The longitudinal success of restorative or rehabilitation of endodontically

treated teeth depends on the quality of the restoration , its clinical adaptation and on the

health of the supporting tissue. Endodontic posts have shown to improve the retention of

a foundation core restoration in situations in which endodontically treated teeth have a

significant loss of coronal tooth structure. The posts reinforcing the roots are

controversial and depends on the post system selected and the residual dentin remaining.

The selection of a post and core system should satisfy many interrelated biologic,

mechanical , and esthetic factors to optimally restore the endodontically treated tooth to

adequate form and function. The prefabricated fiber reinforced posts are opted instead of

the traditional cast posts and cores and prefabricated metal posts which feature high

rigidity , low aesthetic value , easy corrosion and fracture of largely irreparable character.

The most widely known feature of fiber posts is their elasticity, which is similar to dentin

and composite resins, because of which stress distribution during clinical function is

uniform and spreads along the entire root and reduces the risk of root fracture. They also

feature good aesthetic value, absence of corrosion , adhesive cementation and easy

removal if needed.

Different resin luting agents and corresponding bonding systems have been proposed for

cementing tooth coloured posts. They are based on Bis-GMA, TEG-DMA, UDMA and

HEMA resin systems. Bonding to dentin may be achieved using etch and rinse ( total

etch) and self adhesives. Simplified versions of these adhesives have made bonding

simpler , faster and more user friendly. The bonding of the luting agent with the root

surface and also with the surface of the post making the root , post and the luting agent

one mass ( monobloc ) has been found to reinforce the tooth and increase the fracture

resistance.

There is a limited information about the effect of luting cements on the fracture resistance

of endodontically treated roots restored with fiber posts. The purpose of this study is to

evaluate the fracture resistance of endodontically treated roots restored with fiber posts

using Calibra, [Bis-GMA] ( Dentsply) , Smartcem 2 [BisGMA] (Dentsply) and

Permaflow DC,[ Bis-GMA] ( Ultradent) resin cements. Smartcem 2 is a newer material

whose bond strength and reinforcing capability of the endodontically treated roots has not

been evaluated.

.6.2 REVIEW OF LITERATURE

A study was conducted to evaluate the bond strengths of two dual-cured luting agents

used for cementation of four different fiber-reinforced composite (FRC) posts by using a

push-out test and to evaluate the failure modes of these systems.The posts used were

translucent quartz FRC posts, opaque glass FRC post, individually formed electrical glass

fiber posts cemented with variolink ll and RelyX Unicem. Results indicated that the Fiber

reinforced composite posts luted with Variolink ll showed higher bond strengths.

A study evaluated the resistance of fracture of endodontically treated teeth restored with

different post systems - titanium, quartz fiber, glass fiber, and zirconia posts which were

cemented using RelyX ARC adhesive resin cement & restored with composite cores, and

fabricated metal crowns. The results showed that the teeth restored with quartz fiber

posts exhibited higher resistance to fracture than ( titanium , glass fiber and zirconia

posts).

An in vitro study was conducted to measure the force required to displace four different

endodontic posts (an experimental, Para-Post, Flexi-Post, and V Lock) when tensile,

torsion, or compressive forces were applied. The posts were cemented with Flexi - Flow

resin cement. Threaded posts provided higher tensile resistance. Flexi-Posts provided the

greatest resistance to torsion and tensile loading.

A study performed evaluated the effect of different post designs and varying amounts of

post-to-canal adaptation on the fracture resistance of endodontically treated teeth. Cast

post and cores and crowns were waxed, cast, and luted with zinc phosphate cement on a

static loading device. Tapered post increases the fracture resistance of teeth, but upon

failure renders the tooth nonrestorable. Parallel-sided posts had a lower frequency of

fracture upon failure, involving less tooth structure. Parallel-sided posts surrounded by

large amounts of cement had no significant effect on failure loads.

 A study evaluated the fracture resistance of endodontically treated teeth restored with

glass fiber and zircon posts which were cemented with resin cement (Panavia F). The

control group was restored with a nickel-chromium post and core. The results indicated

that the glass fiber & zircon posts exhibited lower failure loads than the nickel chromium

cast post and core.

 

6.3 OBJECTIVE OF THE STUDY

Objective is to study the fracture resistance of endodontically treated roots wherein the Easy Fiber Posts are cemented with the following luting resin cements – Calibra (Dentsply), Smartcem 2 ( Dentsply) , Permaflow DC ( Ultradent ) and subjected to compressive loading under Universal Testing Machine (Instron).

7. MATERIALS AND METHODS

7.1 SOURCE OF DATA

Forty five extracted human single rooted maxillary central incisors will be obtained from

The Department of Oral And Maxillofacial Surgery, Krishnadevaraya College of Dental

Sciences and Hospital.

METHOD OF COLLECTION OF DATA

Sample size – Forty five extracted maxillary central incisors

Inclusion Criteria – Single rooted maxillary central incisors should be caries, restoration and cracks free.

Exclusion Criteria – Teeth with preexisting caries, restoration and cracks.

METHODOLOGY

ARMAMENTARIUM AND MATERIALS

1. Extracted maxillary central incisors

2. Endodontic hand K files – 10, 15-40, 45-80.

3. Saline solution

4. Gutta percha , resin sealer ( AH Plus )

5. Sodium hypochlorite ( 2.5%) , EDTA (17%)

6. Diamond disc

7. X – Ray films

8. Fiber posts ( Easy Posts size 1, (0.8mm) Dentsply )

9. Precision drill number 1 ( Dentsply)

10. Resin luting cements – Smartcem 2 , Calibra and Permaflow DC

11. Acrylic resin cylindrical moulds

STUDY METHOD

For this study forty five extracted human maxillary central incisors free of caries ,cracks

and having approximately similar dimensions will be used.

The teeth selected will be stored in saline solution at ambient temperature. The teeth are

decoronated at the cemento- enamel junction using a diamond disc to create 16 mm long

specimens, followed by determining the canal patency by passing a size 10 K – File

through the apical foramen and working lengths will be established 1.0 mm short of the

apical foramen.

The canal instrumentation will be performed till the number 40 K -File being the master

apical file followed by a step-back preparation (1mm) upto size 70 K – File. During

instrumentation, canals will be irrigated with 2.5% sodium hypochlorite solution and

17% EDTA. The obturation will be performed using gutta percha and AH Plus sealer

(Dentsply) with cold lateral compaction. After 24 hours gutta percha is then removed

from the coronal and middle thirds of the roots using peeso reamer number 1, leaving

5mm of intact gutta percha.

The post spaces will be prepared to a depth of 10mm predrilling firstly with the Easy Post

Largo drill number 1 and then by precision drilling with the calibrating drill number 1.

Following the post space preparation the canals will be irrigated with sterile water and

are dried with paper points. Presence of any residual gutta percha in the walls of the post

space will be checked by radiographic evaluation.

All the specimens will then be divided into three 3 groups, each group containing fifteen

samples each for cementation of the Easy Fiber Posts (size 1, 0.8mm diameter).

GROUP 1 Cementation of Easy Post using CALIBRA (Dentsply)

GROUP 2 Cementation of Easy Post using SMARTCEM 2 (Dentsply)

GROUP 3 Cementation of Easy Post using PERMAFLOW DC (Ultradent)

The post cemented roots will be stored in saline solution at ambient temperature and

acrylic resin cylinders are obtained using cylindrical moulds. Then the specimens will be

mounted on the lower plate of the universal testing machine (Instron) and a compressive

loading is applied vertically to the coronal surfaces of the roots with a loading rate of

1mm min until fracture occurs and the load at which failure will occur is recorded and

expressed in Newtons.

STATISTICAL ANALYSIS :

The results obtained will be statistically evaluated using Anova Test and Tukey’s Test and the fracture toughness of the endodontically treated root restored with fiber posts using different resin cements will be assessed and compared

7.3 DOES THE STUDY REQUIRE ANY INVESTIGATIONS OR INTERVENTIONS TO BE CONDUCTED IN PATIENTS OR OTHER HUMANS

No, not required

7.4 HAS ETHICAL CLEARANCE BEEN OBTAINED FROM YOUR INSTITUTION Not Applicable

8. LIST OF REFERENCES

Ayse D. Kececi , B. Ureyen Kaya , Necdet Adanir . Micro push-out bond strengths of

four fiber- reinforced composite post systems and 2 luting materials. OOOOE

2008;105:121-128.

Begum Akkayan , Turgut Gulmez . Resistance of fracture of endodontically treated teeth

restored with different post systems. J Prosthet Dent 2002; 87: 431-7.

John O. Burgess , James B. Summit , J. William Robbins. The resistance to tensile,

compression, and torsional forces provided by four post systems .J PROSTHET DENT

1992 ; 68:899-903.

John A. Sorensen , Michael J. Engelman .Effect of post adaption on fracture resistance of

endodontically treated teeth. J PROSTHET DENT 1990;64:419-24.

Hai Qing , ZhiMin Zhu , YongLie Chao , WeiQun Zhang. In vitro evaluation of the

fracture resistance of anterior endodontically treated teeth restored with glass fiber and

zircon posts. J Prosthet Dent 2007; 97: 93-8.