Rajiv Gandhi University of Health Sciences s73

RAJIV GANDHI UNIVERSITY OF HEALTH SCIENCES BANGALORE, KARNATAKA.

1. NAME OF THE CANDIDATE AND DR.MADAN KUMAR M ADDRESS POST GRADUATE STUDENT, DEPARTMENT OF CONSERVATIVE DENTISTRY AND ENDODONTICS, DAYANANDA SAGAR COLLEGE OF DENTAL SCIENCES BANGALORE.

2. NAME OF THE INSTITUTE DAYANANDA SAGAR COLLEGE OF DENTAL SCIENCES BANGALORE.

3. COURSE OF STUDY AND SUBJECT MASTER OF DENTAL SURGERY CONSERVATIVE DENTISTRY AND ENDODONTICS 4. DATE OF ADMISSION TO COURSE 03.05.2010

5. TITLE OF THE TOPIC:

“EFFECT OF DIFFERENT RE-INFORCEMENT TECHNIQUES ON FRACTURE RESISTANCE OF ENDODONTICALLY TREATED TEETH- AN IN VITRO STUDY.” 6. BRIEF RESUME OF THE INTENDED WORK:

6.1 NEED FOR THE STUDY: -

The success of endodontic therapy has been inextricably tied to the quality of the final endodontic restoration.1 Although not the primary cause of failure, tooth fracture may be the most detrimental because it often results in extraction 2.

Endodontically treated teeth, as compared to teeth with healthy pulps, are considered more susceptible to fracture because of dental caries, endodontic access preparation and root canal preparation.3

On the survival rate of endodontically treated teeth, it has emerged that preserving sound tooth structure is the key to improving their longevity. With recent advancements in adhesive technology and new stronger composite materials, it is possible to create conservative, highly esthetic restorations that are bonded directly to teeth without the need for extra coronal restorations in the form of crowns. They are more practical, less expensive and less invasive than other techniques. 2

1 In recent years the development of fiber reinforced composite technology has created newness in metal free, adhesive restorative dentistry.2The fiber reinforced composite posts have high tensile strength and modulus of elasticity similar to that of dentin, thereby flex under load and lead to an improved stress distribution.4 But consensus can be found in the literature that teeth restored without posts have similar fracture resistance to those with various post systems.5 In particular a technique of corono-radicular stabilization of endodontically treated teeth called Nayyar’s technique has been widely reported where 3mm of gutta percha was removed from the canal orifice and subsequently filled with composite resin.6 Use of polyethylene fiber has been extensively studied in the last few years as root canal post, where the fibre saturated in resin is condensed tightly in the canal space 4.More recently the polyethylene fibers are also being used in coronal composite restorations to improve fracture resistance of endodontically treated teeth with encouraging results.7 Hence the search for alternative techniques and materials that help not only improve retention but also enhance fracture resistance of tooth is still on.

Therefore the need of this study is to compare the fracture resistance of endodontically treated teeth restored with Nayyar’s core technique and polyethylene woven fibre post with and without polyethylene fibre reinforced composite resin restoration and also to evaluate the type of fracture(favorable/unfavorable) seen with the above techniques.

6.2 REVIEW OF LITERATURE:

A comparative study on the fracture resistance of teeth restored with Nayyar’s core concluded that endodontically treated teeth restored with either composite resin or amalgam corono-radicular preparations exhibited greater fracture resistance than those without 6. An in vitro study evaluating the effect of fiber insertion on root filled teeth restored with composite was conducted, results of which indicated that use of fiber under composite restorations significantly 7 increased fracture resistance.7

The reinforcement effect of polyethylene fiber in root filled teeth by different techniques was studied in which highest fracture resistance was observed when the fiber was placed on the occlusal surface of the restoration in bucco- lingual direction.8 Results of another study on the fracture resistance of premolars with one remaining cavity wall concluded that there was no significant difference in fracture resistance between polyethylene woven fibre posts, custom made glass fibre reinforced composite post, titanium post and a composite resin restoration.4

A study done on thin walled roots restored with different post systems concluded that fracture resistance of polyethylene woven fiber was less than that of cast metal post but similar to that of fiber post and a corono-radicular restoration.9 6.3 OBJECTIVES OF THE STUDY:

2 The aim of this in vitro study is 1) To compare the fracture resistance of endodontically treated maxillary premolars restored with a) Nayyar’s core technique with and without fiber reinforced composite restoration b) Polyethylene fiber reinforced composite resin post with and without fiber reinforced composite restoration ) 2) To evaluate the type of fracture (favorable or unfavorable) seen with the above techniques.

MATERIALS AND METHODS:

7.1 SOURCE OF THE DATA 50 Freshly extracted teeth will be obtained from the department of Oral And Maxillofacial Surgery, Dayananda Sagar College of Dental Sciences Bangalore.

MATERIALS-

1. Diamond coated burs 2. High speed handpiece 3. Endodontic files 4. Irrigating solution 5. Gates glidden drills 6. Guttapercha points 7. Root canal sealer 8. Polyethylene fiber 9. Composite 10. Matrix band 11. Universal testing machine 12. Thermocycler

7.2 METHODS OF COLLECTION OF DATA

50 Non carious maxillary premolars will be collected .Endodontic access cavities will be prepared followed by biomechanical preparation and obturation with gutta-percha. Palatal cusp will be removed and cavities will be divided into 5 groups of 10 samples each

Group 1(control) – Entire cavity restored with composite resin following obturation

3 Group 2 Subgroup A- Post space prepared to a depth of 3mm from canal orifice. Radicular space and cavity restored with dual cure composite resin.( Nayyar’s technique)

Subgroup B- Post space prepared to a depth of 3mm and restored with dual cure composite.( Nayyar’s technique) and cavity restored with fibre inserts in composite resin.

Group 3 Subgroup A- Post space prepared to a depth of 10mm from canal orifice followed by placement of polyethylene woven fibre in the root canal and coronal cavity restored with composite resin.

Subgroup B - Post space prepared to a depth of 10mm from canal orifice followed by placement of polyethylene woven fibre in the root canal and coronal cavity restored with fibre insert composite resin.

Teeth will then be thermocycled (500 cycles at 5 to 55 degree + 2 degree.)30 seconds dwell time followed by incubation.

Teeth will then be mounted in a block of cold cure acrylic resin and subjected to compressive strength of 0.5 mm/min at an angle of 450 using universal testing machine. Fracture resistance between the groups will then be compared.

The fracture patterns will also be evaluated. Teeth with fracture line extending below the CEJ will be classified as unfavorable and those above the CEJ will be categorized as favorable.

INCLUSION CRITERIA:

1. Intact molars extracted for periodontal reasons

EXCLUSION CRITERIA: - 1. Carious teeth 2. Previous restorations 3. Previous endodontic treatment 4. Pre-existing fractures or cracks

4 The following statistical tests will be carried out:

Statistical analysis of data will be done by using ANOVA Analysis.

7.3 Does the study require any investigations or interventions to be conducted on patients or other humans or animals?

No, the study does not require any investigations or interventions to be conducted on patients or other humans or animals, as it is an in vitro study

7.4 Has ethical clearance been obtained from your institution in case of 7.3?

8. LIST OF REFERENCES:

1.Smith CT.Schuman N.Restoration of endodontically treated teeth :a guide for the restorative dentist.Quintessence Int 1997;28:457-62 2. Sengun A, Cobankara FK. Effect of a new restoration technique on fracture resistance of endodontically treated teeth . Dental Traumatology 2008; 24:214-219. 3. Cobankara FK, Unlu N. The effect of different restoration techniques on the fracture resistance of endodontically treated molars .Operative Dentistry 2008, 33-5,526-533. 4. Kivanc BH, Alacam T. Fracture resistance of premolars with one remaining cavity wall restored using different techniques. Dental Materials Journal 2010; 29(3):262-267. 5. Fokkinga WA,Bell AM.Ex vivo fracture resistance of direct resin composite complete crowns with and without posts on maxillary premolars. IEJ ,38.2005 6.Ferrier S.Sekhon BS.A study on fracture resistance of Nayyar cores of three restorative materials.Operative Dentistry 2008.33-3,305-311. 7.Belli S. Erdimir A. The effect of fibre insertion on fracture resistance of root filled molar teeth with MOD preparations restored with composite. International Endodontic Journal 2005, 38, 73-80. 8.. Belli S. Erdimir A. Reinforcement effect of polyethylene fibre in root filled teeth:comparison of two restoration techniques. International Endodontic Journal 2006,.39,136-142. 9. Kivanc BH, Alacam T. Fracture resistance of walled roots restored with different post systems. International Endodontic Journal 2009,42(11)997-1003

5 9. SIGNATURE OF THE CANDIDATE

10. REMARKS OF THE GUIDE

11 NAME AND DESIGNATION OF Dr. Roopa R Nadig. Professor and Head, 11.1 GUIDE Department Of Conservative Dentistry And Endodontics, Dayananda Sagar College Of Dental Sciences Bangalore.

11.2 SIGNATURE

11.3 CO-GUIDE

11.4 SIGNATURE

11.5 HEAD OF THE DEPARTMENT Dr. Roopa R Nadig. Professor and Head, Department Of Conservative Dentistry And Endodontics, Dayananda Sagar College Of Dental Sciences Bangalore.

11.6 SIGNATURE

12. 12.1 REMARK OF THE CHAIRMAN AND PRINCIPAL

12.2 SIGNATURE