RAJIV GANDHI UNIVERSITY OF HEALTH SCIENCES,
BANGALORE, KARNATAKA.
ANNEXURE II
PROFORMA FOR REGISTRATION OF SUBJECTS FOR DISSERTATION
1. / Name of the CandidateAnd Address (in block letters) /
Dr. MAHALAKSHMI V.
POSTGRADUATE STUDENT
DEPARTMENT OF CONSERVATIVE DENTISTRY AND ENDODONTICS,BAPUJI DENTAL COLLEGE AND HOSPITAL,
DAVANGERE – 577 004,
KARNATAKA.
2. /
Name of the Institution
/ BAPUJI DENTAL COLLEGE AND HOSPITAL,DAVANGERE – 577 004,
KARNATAKA.
3. / Course of Study
AND SUBJECT / MASTER OF DENTAL SURGERY CONSERVATIVE DENTISTRY AND ENDODONTICS
4. / Date of admission to THE COURSE / 14/05/2012
5. /
Title of the dissertation:
/ “evaluation of the effect of flowable composite, vitremer and biodentine as intraorifice barriers on the fracture resistance and coronal microleakage of roots obturated with gutta percha – an in vitro study.”6. / BRIEF RESUME OF INTENDED WORK
6.1 Need for the study:
Endodontic therapy aims to eliminate infections in root canal system and to prevent re infections from apical and coronal directions1. A number of studies have indicated that leakage whether from coronal or apical direction adversely affects the success of root canal treatment. In recent times, it has been suggested that apical leakage may not be the most important factor leading to failure of endodontic treatment but that coronal leakage is far more likely to be major determinant of clinical success or failure.2To prevent coronal microleakage intraorifice barriers can be placed into the orifices of the root canals by replacing a part of the gutta percha .These barriers can additionally reinforce the tooth structure, thereby preventing vertical root fracture to an extent. Vertical root fracture is one the serious complication of root canal treatment that can occur before, during or after root canal obturation. Studies have shown that the 11 – 13% of extracted teeth with endodontic treatment are associated with vertical root fracture, making it the second most frequent reasons for the extraction of endodontically treated teeth.3
Several materials have been used as intraorifice barrier such as cavit, resin based temporary restorative material, amalgam with varnish, glass ionomer cement and composite resins.2 The most commonly used barriers however are composites and glass ionomers.Biodentine is a newly introduced material in the market which micro mechanically bonds to the tooth surface without surface preparation. It is used for perforation repair, retrograde surgical filling, External /internal resorption. But studies are scarce in terms of its role as intraorifice barrier.
Therefore, the objective of this study is to evaluate the effect of flowable composite, Vitremer and Biodentine as intraorifice barriers on the fracture resistance and coronal microleakage of roots obturated with gutta percha.
RESEARCH HYPOTHESIS: Flowable composite, Vitremer and Biodentine when used as intraorifice barriers would have an effect on the fracture resistance and coronal microleakage of the roots obturated with gutta percha.
NULL HYPOTHESIS: Flowable composite, Vitremer and Biodentine when used as intraorifice barriers have no effect on the fracture resistance and coronal microleakage of the roots obturated with gutta percha.
6.2 Review of literature:
An in vitro study was done to evaluate the effect of different intraorifice barrier on the fracture resistance of the root obturated with resilon or gutta percha. Crowns were sectioned off and were divided into two groups based on type of obturating material used after biomechanical preparation: Group1 gutta percha with AH plus sealer and Group 2 resilon with epiphany sealer. The groups were further sub grouped with respect to type of intraorifice barrier used after the removal of 3mm of coronal portion of root fillings (1) MTA (2) Vitremer (3) fibre reinforced composite. The specimens were mounted vertically on a universal testing machine and compressive force was applied at a crosshead speed of 1mm/min until the fracture occurred. Data were statistically analyzed. The study concluded that the use of vitremer and FRC significantly improved the fracture resistance compared to MTA.3
An in vitro study was done to evaluate the reinforcing effect of a resin modified GIC in the restoration of immature roots. Crowns of 56 extracted maxillary central incisors were removed in order to obtain standard length of 13mm. root canals were enlarged to simulate immature teeth. After the apical 2mm of the root canal was obturated with gutta percha and AH plus sealer, the specimen were divided into two groups ; Group A untreated and served as positive control and Group B the canals were reinforced with resin modified glass ionomer cement. All the teeth were subjected to compressive force using instron testing machine until the fracture occurred. Data were statistically analyzed. The study concluded that resin modified GIC increased fracture resistance in immature teeth.4
An in vitro study was done to evaluate the intraorifice sealing materials for coronal microleakage in obturated root canals. After root canal treatment was performed on 104 extracted human single rooted premolar, 3mm of gutta percha was replaced by one of the six filling materials to seal the intraorifice (three flowable composites, hybrid composite, cavit, IRM). After thermocycling and immersion in India ink for 5days, the teeth were evaluated for dye penetration along canal walls. Data was statistically analyzed. The study concluded that all of the three flowable composite, hybrid composite sealed better than cavit and IRM.1
An in vitro study was conducted to evaluate the sealing ability of three materials in the orifice of root canal systems obturated with gutta percha. 130 single roots were randomly assigned to 12 experimental or 2 control groups. 40 specimens each were sealed with 1, 2, 3 or 4mm of cavit, pro root MTA or tetric. Smear layer was removed and canal systems were obturated with gutta percha using lateral compaction technique. Gutta percha was removed to the experimental depth, experimental materials placed in the orifice in the orifice and roots were submerged in India ink in a vacuum flask. Specimens were demineralized and leakage was measured using a 10X stereomicroscope. Data was statistically analyzed. There was no significant interaction between test material and orifice depth. However tetric demonstrated a significantly better seal than pro root or cavit.5
6.3Objective of the study:
To evaluate the effect of flowable composite, Vitremer and Biodentine as intraorifice barriers on the fracture resistance and coronal microleakage of roots obturated with gutta percha.
MATERIALS AND METHODS:
7.1 Source of Data :
The study will be conducted on 90 extracted single rooted mature human mandibular premolar teeth with single canal .
Inclusion criteria:
1. Teeth indicated for extraction due to orthodontic reason belonging to the age group 17 to 35 years.
2. Teeth devoid of any developmental defects.
Exclusion criteria:
1. Dental caries.
2. Any previous restorative or endodontic treatment
3. Fractured teeth.
4. Teeth with abrasion, erosion.
. The teeth will be stored for 2 days in sodium hypochlorite (NaOCl), at room temperature, to remove organic debris. Subsequently, they will be scaled with ultrasonic instruments, washed with distilled water, and immersed in 10% formalin solution until use.
Sample size determination:
Based on previously published article, the sample size required for the study was estimated using the formula
n = 2 * t2 *s2
d2
where t = theoretical value of ‘t’ distribution for 95% confidence =2.13
s = pooled standard deviation = 0.6 [specimen study]
d = minimum expected difference between two groups=0.58
substituting the values n = 2*2.132*0.62 = 9.7 [hence each group should contain 10 or
0.582 more specimens]
level of significance(α) = 5%
Maximum allowable (β) = 20%
Power of the study (1-β) = 1- 0.2 = 0.8 = 80%,
Materials and equipment :
1. Extracted human mature premolar teeth with single root canal.
2. Caliper.
3. Hand files. (Dentsply)
4. Protaper rotary files
5. Micromotor. (NSK)
6. Distilled water
7. Sodium Hypochlorite (NaOCl). (5.25% and 2.25%)
8. 17% Ethylene Diamine Tetra Acetic acid (EDTA)
9. Protaper universal gutta percha points.
10. AH plus sealer.
11. BIODENTINE.(Septodont)
12. Flowable Composite.( Esthet-X Flow, Dentsply)
13. Xeno V (Dentsply)
14. Vitremer.( 3M ESPE )
15. Universal Testing Machine.(Hounsfield, instron USA)
16. Nail polish (Revlon)
17. India ink
18. Scalpel
19. 5% Hydrochloric acid [HCl]
20. Ethyl alcohol
21. Methyl salicylate
22. Stereomicroscope
23. RVG
7.2 Method of Collecting Data (including sampling procedure if any):
Teeth will be reduced to a standardized root length of 14mm from the coronal aspect. The mesio- distal and bucco- lingual dimensions will be measured with a caliper. Roots with ±10 % difference from those values will be discarded.
Specimen preparation :
Canal length will be determined by using a #10K file and working length will be determined by substracting 1mm from the canal length. Root canals will then be instrumented with Protaper rotary files in conjunction with 2ml of 5.25% sodium hypochlorite (NaOCl) between each file size. Root canals will be enlarged to size F4 till the working length and final irrigation will be done with 5ml 17% EDTA and 5ml of 2.5% NaOCl. Following this, canals will be flushed with 10ml distilled water to avoid prolonged effect of EDTA and NaOCl and dried with paper points.
All the samples will be obturated using Protaper universal gutta percha points and AH plus sealer. With the aid of a heated instrument coronal 3mm of root filling will be removed for all the samples except for the control groups and will be confirmed by using RVG.
All samples will be randomly divided into following two main experimental groups:
Group 1: fracture resistance test [n=40]
Group 2: dye penetration test for coronal microleakage [n=50].
In fracture resistance test group, samples will be further divided into four subgroups according to the intraorifice barrier placed with 10 specimen in each subgroup
GROUP 1: Fracture resistance test
Ø Subgroup A: Flowable composite in conjunction with self etching dentin bonding agent.
Ø Subgroup B: Vitremer
Ø Subgroup C: BIODENTINE
Ø Subgroup D: No barrier (CONTROL)
In dye penetration test group samples will be divided into five subgroups with 10 samples in each subgroup.
GROUP 2: Dye penetration test
Ø Subgroup 1: Flowable composite in conjunction with self etching dentin bonding agent.
Ø Subgroup 2: Vitremer
Ø Subgroup 3: BIODENTINE
Ø Subgroup 4: Control. (no barrier is placed and orifice is exposed to dye)
Ø Subgroup 5: Control (orifice completely sealed with three layers of nail polish)
After the placement of intraorifice barrier the specimen will be stored at 37degree centigrade and 100% humidity for 1 week to allow the material to set completely.
Fracture test :
The apical root ends will be embedded along their long axis in self curing acrylic blocks leaving 9mm of each root exposed. The specimen will be then mounted in a universal testing machine. A custom stainless steel loading fixture with a 2mm spherical tip will be centered over the canal opening. A compressive force will be applied at a cross head of crosshead speed of 1mm/min until the fracture occurs.6 The forces necessary to fracture each root will be recorded in Newtons.3
Dye penetration test:
All of the experimental teeth and Subgroup 4 control group will receive three layers of nail polish leaving only the area of the canal orifice exposed. All the surfaces of the Subgroup 5 control will be completely sealed with three layers of nail polish. For each specimen, root apex will be blocked by sticky wax.
The teeth will be immersed in India ink for 5days. Following the exposure to dye, the teeth will then be rinsed in tap water and nail polish will be completely removed with a scalpel. Then the teeth will be decalcified in 5% hydrochloric acid [HCl] for 3days with constant stirring followed by running water wash. The teeth will be dehydrated for 3hours each of 50%, 75% and 95% ethyl alcohol and cleared by immersion into methyl salicylate. Leakage will be observed by using a 10X stereomicroscope and measured to greatest penetration from the coronal extent of orifice material.1
Statistical analysis
Results will be compared using one way ANOVA for multiple comparisons followed by post hoc tukey test for pair wise comparison.
7.3: Does the study require any investigation or interventions to be conducted on patients or other humans or animals? If so, please describe briefly.
YES( Study requires the use of extracted human premolar teeth )
7.4: Has ethical clearance been obtained from your institution in case of 7.3
YES ( Ethical clearance report attached here with).
8. LIST OF REFERENCES:
1. Qian ZJ, Qi Z, Jie HE. An evaluation of intraorifice sealing materials for
coronal microleakage in obturated root canals. Chin J Dent res 2009;12(1):31-6
2 Sritharan A. Discuss that the coronal seal is more important than the apical for endodontic success. Aus Endod J 2002; 28: 112-15.
3 Emre N, Ozgur U, Emre A, Veli D, Zafer CC, Pek KV, et al. Effect of different intraorifice barriers on the fracture resistance of roots obturated with resilon or gutta percha. J Endod june 2010; 36(6):1061-63.
4 Goldberg F, Kaplan A, Roitman M, Manfre` S, Picca M. Reinforcing effect of a resin modified glass ionomer in the restoration of immature roots in vitro. Dent Traumatol 2002; 18: 70-2.
5 Stephan J, James K, Karen W, William L, Charles L. Sealing ability of three materials in the orifice of root canal systems obturated with gutta percha. J Endod 2006; 32(3): 225-27.
6 Naumann M, Metzdorf G, Fokkinga W, Watzke R, Sterzenbach G, Bayne S, et al. Influence of test parameters on in vitro fracture resistance of post-endodontic restorations: a structured review. Oral rehabil 2009; 36:299-312.
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