RAJIV GANDHI UNIVERSITY OF HEALTH SCIENCES, BANGALORE,
KARNATAKA, INDIA
ANNEXURE – II
PROFORMA FOR REGISTRATION OF SUBJECT FOR DISSERTATION
1 / NAME OF THE CANDIDATE AND ADDRESS(IN BLOCK LETTERS) / DR. SANGEETHA.K.M
POST GRADUATE STUDENT,
DEPARTMENT OF PROSTHODONTICS
INCLUDING CROWN AND BRIDGE,
BAPUJI DENTAL COLLEGE AND HOSPITAL, DAVANGERE – 577004,
KARNATAKA.
2 /
NAME OF THE
INSTITUTION
/BAPUJI DENTAL COLLEGE AND HOSPITAL, DAVANGERE – 577004,
KARNATAKA.3 / COURSE OF STUDY AND
SUBJECT /
MASTER OF DENTAL SURGERY IN
PROSTHODONTICS INCLUDING
CROWN AND BRIDGE.
4 / DATE OF ADMISSION TOCOURSE / 25/05/2012
5 / TITLE OF THE TOPIC / “A COMPARATIVE EVALUATION OF THE EFFECT OF TWO ENDODONTIC SEALERS & LUTING CEMENTS ON THE TENSILE BOND STRENGTH OF A GLASS FIBER POST BEFORE AND AFTER ARTIFICIAL AGING”- AN IN-VITRO STUDY
6. BRIEF RESUME OF THE INTENDED WORK
6.1 Need for the study:
Endodontically treated teeth, often resulted into the loss of a significant part of tooth structure and dehydration making them more susceptible to fracture. Posts are often required to restore these teeth to provide retention and resistance for a core material and to provide coronoradicular stabilization.1
Traditionally, posts were either prefabricated or custom cast in metal, but their low flexibility leads to root fracture. The tooth-colored endodontic posts such as fiber reinforced posts has become more popular in recent years because of their benefits regarding mechanical properties, esthetics, and removability offering predictable clinical performance in several ways.2
Most frequent failures associated with these type of posts are loss of retention and post fracture. Some of the factors that can influence the retention of a post include its shape and design, its length and diameter, endodontic sealer & luting cement, coronal tooth preparation, water storage and thermocycling.1,3
Fiber posts are commonly bonded into the post space with resin based cements having elastic modulus similar to that of post and dentin to improve retention. In the literature, it has been observed that eugenol, which is present in many dental products including most endodontic sealers inhibit the polymerization of composite resin cements. However, the clinical relevance of this interaction is still a controversy.1
Moreover, it has been clinically observed that the dislodgement of post retained restorations usually occurs after a period of functional service as a result of different stress factors, such as temperature change and mechanical loading. But most of the invitro studies that tested retention of endodontic posts were performed shortly after cementation, without any type of simulation of oral conditions or artificial aging procedures.3,4
Hence the present in-vitro study is intended to evaluate and compare the effect of two endodontic sealers & luting cements on the tensile bond strength of a glass fiber post before and after artificial aging.
HYPOTHESIS:
Research hypothesis (H1): The tensile bond strength of a glass fiber post placed in tooth roots will be influenced by the types of endodontic sealers & luting cements, or by artificial aging.
Null hypothesis (H0): The tensile bond strength of a glass fiber post placed in tooth roots will not be influenced by the types of endodontic sealers & luting cements, or by artificial aging.
6.2 REVIEW OF LITERATURE:
· A study was conducted to determine the effect of residual eugenol in the post space on the retention of ParaPost dowels luted with Panavia Ex composite resin cement and zinc phosphate cement. Authors confirmed that eugenol significantly reduced the retention of ParaPosts with Panavia resin cement and zinc phosphate cement is the least affected by eugenol.5
· Authors conducted a study to evaluate the effect of eugenol and non eugenol endodontic sealer on the retention of prefabricated posts luted with zinc phosphate cement or resin cement. Each combination of sealer and post cement was tested for retention on an Instron testing machine. It was concluded that zinc phosphate cement produced higher retention values irrespective of the sealer used.6
· Effect of five dental cements on the retention of three endodontic posts was studied in an invitro study. Posts used were - Flexi post, Access posts, and Parapost cemented with five dental cements - Flexi Flow, zinc phosphate, Advance, Duet and ketac-cem. Flexi posts dowel with Flexi flow cement obtained the highest retentive value and ParaPosts dowel with duet cement exhibited the lowest retention value.7
· An invitro study was conducted to compare the retention of five different cements used to lute prefabricated dowels in root canals previously obturated with gutta percha and a zincoxide eugenol sealer. Dowel space preparation and cementation was done one week after obturation. Luting cements used were Panavia 21, ketac-cem glass ionomer cement, zinc phosphate and parapost composite. Results showed that Panavia 21 cement demonstrated significantly greater retention than zinc phosphate and parapost composite cements.8
· Authors conducted a study to compare the titanium dowel retention using four different luting agents after artificial aging procedures such as water storage, thermocycling and mechanical loading. It was concluded that artificial aging procedures negatively affected the retention of endodontic dowel.4
· A study on the effect of three endodontic sealers (AH 26, Endofil , Tubliseal) on the bond strength of prefabricated fiber posts luted with three resin cements (RelyX unicem, Paracore, Variolink) was conducted. It was observed that Endofil and Tubliseal (eugenol based) sealers demonstrated significantly reduced mean bond strength for prefabricated fiber posts luted with resin cement. Rely X unicem resin cement exhibited higher mean bond strength than with Paracore and variolink resin cements when a eugenol sealer was used.1
6.3 OBJECTIVES OF THE STUDY:
· To evaluate the effect of two endodontic sealers & luting cements on the tensile bond strength of a glass fiber post before and after artificial aging.
· To compare the effect of two endodontic sealers & luting cements on the tensile bond strength of a Glass fiber post before and after artificial aging.
7. MATERIALS AND METHOD:
7.1 Source of data:
· Sixty four extracted, intact, human permanent mandibular premolars will be collected from Department of Oral and Maxillofacial surgery, Bapuji dental college and hospital, Davangere.
· All the materials will be collected or purchased through scientific chemical or dental supplier.
· Data will be obtained from laboratory based studies.
7.2 Preparation of samples: (including inclusion criterion and exclusion criterion)
SELECTION CRITERION:
a) Inclusion criterion:
· Human permanent mandibular premolar with single root canal
· Extracted for orthodontic purpose from patients between age group 19-35 years.
· Completely formed apices
· Not previously subjected to endodontic and restorative therapy
b) Exclusion criterion:
· Visible crack
· Dental caries
· Developmental anomalies
MATERIALS:
Material / Manufacturer
Radix fiber post/ Easy post
(Glass fiber post) / Dentsply
Endodontic sealers / Tubliseal
Eugenol based sealer / SybronEndo
AH-Plus
(Resin based sealer) / Dentsply
Luting cement
(Composite resin cement) / Panavia-F 2.0
(Dual cure) / Kuraray
RelyX unicem
(Self adhesive) / 3M ESPE
GROUPING:
For the purpose of study, a total of sixty four prepared roots will be randomly divided into two main experimental groups of thirty two each with four subgroups each consisting eight test specimens.
EXPERIMENTAL GROUPS:
GROUP-A (n=32): Specimens obturated using eugenol based sealer. (Tubliseal)
Subgroups:
A1: Glass fiber posts luted with Panavia-F 2.0 cement before artificial aging. (n=8)
A2: Glass fiber posts luted with Panavia-F 2.0 cement after artificial aging. (n=8)
A3: Glass fiber posts luted with RelyX unicem cement before artificial aging. (n=8)
A4: Glass fiber posts luted with RelyX unicem cement after artificial aging. (n=8)
GROUP-B (n=32): Specimens obturated using resin based sealer. (AH-Plus)
Subgroups:
B1: Glass fiber posts luted with Panavia- F 2.0 cement before artificial aging. (n=8)
B2: Glass fiber posts luted with Panavia- F 2.0 cement after artificial aging. (n=8)
B3: Glass fiber posts luted with RelyX unicem cement before artificial aging. (n=8) B4: Glass fiber posts luted with RelyX unicem cement after artificial aging. (n=8)
METHODOLOGY:
Sixty four extracted human permanent mandibular premolars fulfilling the above inclusion and exclusion criteria will be used as samples for study. Teeth will be disinfected in 10% formalin for ten days before being stored in tap water.8,11 Crown will be sectioned, approximately 2mm coronal to the most incisal point of cemento-enamel junction (CEJ) by using a diamond disc at low speed under copious water coolant to standardize length of 15±1 mm.1,9 A size 20K-file (Dentsply-maillefer) will be passively introduced into each root canal until its tip is just visible from root apex. Canal working length will be established by subtracting 1mm from the length obtained with this initial file to select samples that have a working length of 14±1mm.9,10
ROOT CANAL PREPARATION:
Each tooth will be endodontically treated using a conventional step back technique.9 All canals will be cleaned and shaped with hand instrumentation to an ISO k-file size no.50 (Dentsply-maillefer) as Master apical file to standardize all specimens. During the preparation, all canals will be irrigated with 3 ml of 5.25% sodium hypochlorite solution followed by EDTA and will be dried with absorbent paper point.1
Specimens will be then randomly divided into two groups of thirty two each. Each canal will be obturated by lateral condensation technique using gutta percha cones with an ISO.No. 50 as primary gutta percha master cone (Dentsply-maillefer) and one of the two root canal sealer will be used: AH Plus (Dentsply maillefer), an epoxy resin sealer that is free of Eugenol and Tubliseal (eugenol based sealer), respectively.1 Sealer will be introduced into the root canals using a lentulo spiral instrument (Dentsply- maillefer).9 A heated endodontic plugger (No.911) will be used to vertically condense the coronal gutta-percha and subsequently prepare a 3mm deep space coronally for a provisional restoration. All obturated teeth will then be temporized with Cavit (3M ESPE) and stored in 100% relative humidity at room temperature for one day.1
POST SPACE PREPARATION:
After 24hours, canal seal will be removed using round shaped diamond bur. The Gutta percha will then be removed using no. #2 Gates Glidden drill until depth of 8mm.3 The
post preparations will be standardized through flaring with peaso reamer (Mani) from size ( no# 1- 5).1 Post channels will be prepared using a yellow color coded precision
drill matching the diameter of a yellow color coded post( Easy post precision drill, dentsply). Throughout the preparation, posts space will be irrigated with 5.25% sodium hypochlorite followed by EDTA and dried with absorbent paper points.(Dentsply-maillefer).1,3
POST PLACEMENT:
Prefabricated glass fiber posts (N˚1, yellow color coded Radix fiber post/ Easy post-Dentsply) will be used.3 Prior to post cementation, canals will be rinsed with water for 30 seconds and dried with absorbent paper point. Posts will be cemented with one of the luting agents Panavia F2.0 (Kuraray) or RelyX unicem (3M-ESPE) cement. Cements will be mixed according to manufacturer’s instructions. Cement will be applied to each post and the post will be seated in the post space with finger pressure and further adapted to the cavity by gently pressing with an endodontic plugger. Carbide burs will be used to notch the roots and will be mounted in standardized acrylic cylinder.1
ARTIFICIAL AGING:
Specimens for artificial aging will be stored in water at 37oC for thirty days and will be thermocycled for 3500 cycles between 5 and 55oC.3
TENSILE BOND STRENGTH TEST:
Each specimen will be secured in Universal testing machine. The posts will be gripped with a custom made device and tensile load will be applied to the posts until dislodgement occurred. After failure of bond between posts and dentin, the load required for separation of posts will be recorded in Newtons(N).1
SAMPLE SIZE DETERMINATION:
Based on the available information from previous studies on the bond strength of fiber reinforced post, sample size was determined using following formula:
n = 2 x t2 x s2 / d2
where, t= theoretical value of ‘t’ distribution with 95% confidence
=2.13
s = pooled standard deviation (from previous studies)1
=20
d = minimum expected difference in the mean bond strength between the groups1
= 25
Level of significance = 5%
Power of study =1-β
= 1-20
= 80%
Thus,
n = 2x 2.13 x2.13 x20 x 20 / 25x 25
= 7.5 ≈8
STATISTICAL ANALYSIS:
Data obtained from tests will be subjected to statistical analysis. For comparison within multiple groups, One-way ANOVA followed by Post hoc Tukey’s test for group wise comparisons will be used. Comparison between two sub groups will be done by un-paired‘t’ test.
7.3: Does the study require any investigations or interventions to be conducted to patients or other human or animals? If so, please describe briefly: Yes ( study requires the use of extracted human permanent mandibular premolars)
7.4: Has ethical clearance been obtained from your institution in case of 7.3?
Ethical clearance report attached here with
8. LIST OF REFERENCES:
1. Aleisa K, Alghabban R, Alwazzan K, Morgano SM. Effect of three endodontic sealers on the bond strength of prefabricated fibre posts luted with three resin cements. J Prosthet Dent 2012;107(5):322-6.
2. Zicari F, Munck JD, Sootti R, Naert I, Van Meerbeek B. Factors affecting cement post interface. Dent Mater 2012;28(3):287-97.
3. Alba shaireh ZS, Ghazal M, Kern M. Effect of endodontic posts surface treatment, dentin conditioning and artificial aging on the retention of glass fibre reinforced composite resin posts. J Prosthet Dent 2010;103(1):31-8.
4. Balbosh A, Ludwig K, Kern M. Comparison of titanium dowel retention using four
different luting agents. J Prosthet Dent 2005;94(3):227-33.
5. Tjan AH, Nemtz H. Effect of eugenol containing endodontic sealer on the retention of prefabricated posts luted with adhesive composite resin cement. Quintessence Int 1992;23(12):839-44.
6. Schwartz RS, Murchison DF, Walker WA. Effect of eugenol and non-eugenol endodontic sealer cements on posts retention. J Endod 1998;24(8):564-7.
7. Cohen BI, Pagnillo MK, Neuman I, Musikant BL, Deutsch AS. Retention of three endodontic posts cemented with five dental cements. J Prosthet Dent 1998; 79(5):520-5.
8. Hagge MS, Wong RD, Lindemuth JS. Retention strength of five luting cements on prefabricated dowels after root canal obturation with a zinc oxide eugenol sealer: 1. Dowel space preparation / cementation at one week after obturation. J Prosthodont 2002;11(3):168-75.
9. Kalkan M, Usumez A, Ozturk AN, Belli S, Eskitascioglu G. Bond strength between root dentin and three glass-fiber post systems. J Prosthet Dent 2006;96(1):41-6.
10. Carneiro SM, Sousa-Neto MD, Rached FAJr, Miranda CE, Silva SR, Silva-Sousa YT. Push – out strength of root fillings with or without thermomechanical compaction. Int Endod J 2012;45(9):821-8.
11. Kumar M, Sequeira P, Peter S, Bhat G. Sterilisation of extracted human teeth for educational use. Indian J Med Microbiolo 2005;23(4):256-8.
12. Burns DR, Moon PC, Webster NP, Burns DA. Effect of endodontic sealers on dowels luted with resin cement. J Prosthodont 2000;99(3):137-41.
13. Boone KJ, Murchison DF, Schindler WG, Walker WA. Post retention: The effect of sequence of post space preparation, cementation time, and different sealers. J Endodont 2001;27(12):768-71.
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