Biomechanical Loading of Tissues and the Precise Mechanisms of Tissue Response Following
RAJIV GANDHI UNIVERSITY OF HEALTH SCIENCES
KARNATAKA, BANGALORE
ANNEXURE II
PROFORMA FOR REGISTRATION OF SUBJECTS FOR DISSERTATION
1. / Name of the candidate andaddress (in Block Letters) / DR. MAHDI MADDAH MORAVVEJ
DEPT. OF ORTHODONTICS AND DENTOFACIAL ORTHOPAEDICS,
BANGALORE INSTITUTE OF DENTAL SCIENCES AND HOSPITAL AND POSTGRADUATE RESEARCH CENTRE, 5/3 HOSUR MAIN ROAD, BANGALORE – 560 029.
2. / Name of the Institution / BANGALORE INSTITUTE OF DENTAL SCIENCES AND HOSPITAL AND POSTGRADUATE RESEARCH CENTRE, BANGALORE – 560 029.
3. / Name of study and subject / MASTER OF DENTAL SURGERY IN DEPARTMENT OF ORTHODONTICS AND DENTOFACIAL ORTHOPAEDICS
4. / Date of Admission / 24th DECEMBER 2010
5. / Title of the Topic / Effect of adhesive application prior to bracket bonding with flowable composites.
(An In-vitro Study)
6. / BRIEF RESUME OF THE INTENDED WORK:
6.1 Need of the study:
For many decades, the most popular bonding system in orthodontics has been based on the acid etching technique introduced by Buonocore in 1955 and modified for orthodontic purposes by Newman and Rietf during the 1960s.
Two main strategies are used to create durable enamel bonding:
1) The acid etched/composite technique with an intermediate thin layer of resin (also called primer or bonding agent)
2) Self-etching systems or acidic primers combining the etching and priming steps. This minimizes the working time during bonding and eliminates possible damage to the gingival tissue.
The goal of current orthodontic research is to improve the bonding procedure by minimizing the time of working during bonding and debonding without jeopardizing the ability to maintain a clinically useful bond strength.
Recently, flowable composites have been applied for orthodontic use by many clinicians. If a flowable composite without the intermediate low-viscosity resin can guarantee clinically acceptable bond strength to acid-etched enamel, it would be advantageous since it would reduce the number of steps during bonding and decrease the potential for error through contamination during bonding procedure.
Flowable composites merit great attention because of two of their clinical handling characteristics:
1) No stickiness 2) Fluid injectability
The aim of the present study therefore, is to evaluate the effect of applying an adhesive prior to different flowable composite resins on the shear bond strength (SBS) of orthodontic brackets to acid-etched enamel.
6.2 Review of Literature:
1. The aim of the study1 was to determine the shear bond strength (SBS) values of different flowable composites (Pulpdent Flows-Rite, 3M Filtek Flow, and Heraeus Kulzer Flow Line) in comparision with a conventional orthodontic adhesive and the bond failure sites of these composites. Eighty extracted human premolars were divided into four groups of 20 teeth each. Brackets were bonded to the teeth in each test group with different composites, according to the manufacturer’s instructions. SBS values of these brackets were recorded (in MPa) using a universal testing machine. Adhesive remnant index (ARI) scores were determined after the failure of brackets. Data were analyzed using analysis of variance (ANOVA), Tukey honestly significant difference, and chi-square tests. SBS values of groups 1 (Transbond XT), 2 (Flows-Rite), 3 (Flow) and 4 (Flow Line) were found to be 17.10 ± 2.48 MPa, 6.60±3.2 MPa, 7.75± 2.9 MPa and 8.53± 3.50 MPa respectively. The results of this study demonstrate that the orthodontic adhesive (Transbond XT) had higher SBS values than the flowable composites. Results of ANOVA revealed statistically significant differences among the groups (p<.05). The SBS values were significantly lower in all flowable composite groups than the orthodontic adhesive. ARI scores were significantly different between the orthodontic adhesive and all the flowable groups investigated. The use of flowable composites is not advocated for orthodontic bracket bonding because of significantly lower SBS values achieved.
2. In this study2, a new dental flowable composite, Denfil Flow, was evaluated for the bonding of orthodontic brackets by determining its shear bond strength (SBS) and the mode of bond failure after debonding. Eighty extracted human premolars were divided into two equal groups. Metal brackets were bonded to etched enamel using a composite resin control (TransbondXT) or Denfil Flow. After 72 hours of incubation in saline solution at 37 oC, debonding was performed with a shearing force. The SBS and the mode of bond failure were examined. In addition, representative samples from each group were examined by scanning electron microscopy (SEM). No significant difference was observed in the SBS between the groups, and a clinically acceptable SBS was found for the two adhesives. Bond failures occurred mostly in the bracket-adhesive interface, without significant differences between the groups. At SEM analysis, Denfil Flow showed a greater frequency of air bubbles within the resin than did TransbondXT. In conclusion, Denfil Flow displayed the same SBS as traditional composite resins and similar bond failures.
3. This study3 determines the use of a new flowable composite, Denfil Flow, which has shown an acceptable shear bond strength for bonding orthodontic brackets, when used with an intermediate, unfilled, low-viscosity resin. According to the manufacturer, it also shows a good viscosity for use with no preliminary adhesive. This could reduce the total time of bonding procedure while maintaining clinically useful bond strength.. Eighty extracted human premolars were randomly divided into four equal groups. Stainless steel brackets were bonded to etched enamel using (1)Denfil Flow, (2) a traditional flowable composite (Dyract Flow), (3) Denfil Flow composite resin and an intermediate liquid resin, and (4) Transbond XT adhesive. Debonding was performed with a shearing force. The residual adhesive on the enamel surface was evaluated using the adhesive remnant index. The bond strength of Denfil Flow (34.8MPa) showed no significant difference with the other control groups and was clinically acceptable. Denfil Flow and Dyract Flow tended to display cohesive failure within the adhesive. Denfil Flow can be used without liquid resin to reduce the bonding procedure time while maintaining acceptable bond strength.
4. The aim of the study4 was to test the bonding characteristics of four flowable composites for orthodontic bracket bonding. Metal brackets were bonded to acid-etched human enamel using four flowable composites (Grandio Flow, GF: UniFil Flow,UF: UniFil LoFlo Plus, UL: and DenFil Flow, DF), an orthodontic bonding system (Transbond XT, TX), and a restorative composite (Filtek Z250, FZ). After 24 hours of storage in water at 37 oC, a shear bond strength (SBS) test was performed. After debonding, the adhesive remnant index (ARI) was assessed. In addition, the flow and flexural strength of the materials were examined. The SBS for the flowable composites ranged between 7.2 and 8.3 MPa, and TX showed a significantly higher value (mean 10.9 MPa). The flowable composites also demonstrated a significantly superior flowability, yet inferior flexural strength (except for DF) than TX and FZ. Two flowable composites (GF and UL) produced significantly higher ARI scores than TX and FZ, which represented a larger resin remnant on the enamel surfaces after debonding. When considering the SBS and ARI scores obtained in this study, flowable composites with no intermediate bonding resin could be conveniently applied for orthodontic bracket bonding.
5.The aim of the study5 was to evaluate the effect of applying an adhesive, prior to different flowable composite resins, on the shear bond strength (SBS) of orthodontic brackets to acid-etched human enamel. One hundred metal brackets were bonded to 35% phosphoric acid etched human premolars using four flowable composites (Admira Flow, Tetric Flow, Filtek Supreme, Transbond Supreme) and a conventional orthodontic composite resin (Transbond XT). For each experimental group, half of the specimens were bonded in combination with Transbond XT adhesive. After 24 hours of storage, an SBS test was performed. Adhesive remnant index scores were determined after the failure of brackets. Two-way analysis of variance and Student-Newman-Keuls multiple comparison tests were performed at P<.05. When using an adhesive system, the five composites performed equally. The application of adhesive had a significant effect on SBS. Without adhesive, SBS decreased in all groups, except for Transbond Supreme LV. All the test groups exhibited similar bracket failure modes. When using an adhesive system, flowable composite resins exhibited similar SBS. Transbond Supreme was the only resin performing similarly with or without adhesive system application.
6.3 Objectives of the study:
1. To evaluate the effect of applying an adhesive, prior to different flowable composite resins, on the shear bond strength (SBS) of orthodontic brackets to acid-etched human enamel.
2. To analyse the site and mode of failure between experimental groups and to determine the adhesive remnant index.
7 / MATERIALS AND METHOD:
7.1 MATERIALS:
1. One hundred stainless steel metal premolar brackets (3MUnitek, Monrovia, Calif)
2. Four flowable composites
a. Tetric Flow, Ivoclar-Vivadent; Schaan, Liechtenstein
b. Admira Flow, Voco ,Cuxhaven, Germany
c. Filtek Z 350 XT, 3M ESPE
d. Transbond Supreme LV,3M ESPE
3. Orthodontic bonding system-Transbond XT ,3M ESPE
4.Transbond XT primer (3M)
5.37% Phosphoric acid gel ( Etch-37, Bisco)
6.Light cure unit (SELECTOR LA500,Apoza Enterprise Co)
7.2 METHOD:
A total of 100 sound-extracted human premolars will be stored in a 0.5 chloramine T solution at 48 oC for a maximum of 6 months after extraction. The premolars are mounted in a self-cure acrylic block.
The premolars will be divided into 5 groups:
Group I (20 teeth): Bonded withTransbond XT
Group II (20 teeth): Bonded with Tetric Flow
Group III (20 teeth): Bonded with Admira Flow
Group IV (20 teeth): Bonded with Filtek Z350 XT
Group V (20 teeth): Bonded with Transbond Supreme LV
The buccal enamel surface will be etched with 37% phosphoric acid gel for 30 seconds, rinsed for 15 seconds and dried with oil and moisture-free air for 20 seconds until the enamel has a faintly white appearance.
One hundred stainless steel metal premolar brackets with a micro-etched base (3M Unitek, Monorovia, Calif), are directly bonded to the acid-etched enamel.
For each experimental group, half of the specimens (N=10) are bonded with a Transbond XT primer (3M) according to the manufacturer’s instructions and the other half without primer.
Composites are applied to the bracket base, and the bracket are positioned on the tooth and pressed firmly with a Hollenback carver to expel the excess adhesive. In both groups, each bracket will be subjected to a 300 g compressive force using a force gauge (Correx Co, Berne, Switzerland) for 10 seconds, after which excess bonding resin are removed using a sharp scaler. Then, the composite is light cured for 20 seconds from the occlusal edge and 20 seconds from the gingival bracket edge.
The bracket teeth are immersed in sealed containers of deionized water and placed in an incubator 37oC for 72 hours to permit adequate water absorption and equilibration, and an SBS test is performed. The specimens are secured in a jig attached to the base plate of a universal testing machine (Instron Corp, Canton, Mass).A cross head speed of 0.5mm/min2 is used. After debonding, the residual composite remaining on the teeth will be assessed using the ARI (adhesive remnant index) score.
7.3 Does the study require any investigations or interventions to be conducted
on patients or other humans or animals? If so, please describe briefly.
Not applicable
7.4 Has ethical clearance been obtained from your institution in case of 7.3?
Not applicable
8. / LIST OF REFERENCES:
1) Uysal T, Sari Z, Demir A.
Are The Flowable Composites Suitable for Orthodontic Bracket Bonding?
Angle orthod 2004; 74: 697-702
2) D’Attilio M, Traini T, Di Lorio D, Festa F, Tecco S.
Shear Bond Strength, Bond Failure, and Scanning Electron Microscopy Analysis of a New Flowable Composite for Orthodontic Use.
Angle Orthod 2005; 75: 410-415
3) Tecco S, Traini T, Caputi S, Festa F, De Luca V, D’Attilio M.
A New One-Step Dental Flowable Composite for Orthodontic Use- An In Vitro Bond Strength Study.
Angle Orthod 2005; 75: 672-677
4) Ryou D B, Park HS, Kim KH, Kwon TY.
Use of Flowable Composites for Orthodontic Bracket Bonding.
Angle Orthod 2008; 78: 1105-1109
5) Albaladejo A, Montero J, Gomez de Diego R, Lopez-Valverde A.
Effect of adhesive application prior to bracket bonding with flowable composites
Angle Orthod 2011;81:716-720
9. / Signature of Candidate / Dr. Mahdi Maddah Moravvej
10. / Remarks of Guide / This is a genuine study, which will be carried out by the postgraduate student under my supervision and guidance
11.
12. / Name and Designation of
(In block letters)
11.1 Guide
11.2 Signature / DR. SIRI KRISHNA.P
PROFESSOR
DEPARTMENT OF ORTHODONTICS AND DENTOFACIAL ORTHOPAEDICS, BANGALORE INSTITUTE OF DENTAL SCIENCES AND HOSPITAL, BANGALORE
11.3 Head of the Department
11.4 Signature / DR. VINAYA. S.PAI
PROFESSOR AND HEAD
DEPARTMENT OF ORTHODONTICS AND
DENTOFACIALORTHOPAEDICS,
BANGALORE INSTITUTE OF DENTAL SCIENCES AND HOSPITAL,
BANGALORE.
12.1 Remarks of the Chairman and Principal
12.2 Signature
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