POST GRADUATE STUDENT
DEPARTMENT OF ORTHODONTICS AND DENTOFACIAL ORTHOPEDICS
GOVT.DENTALCOLLEGE AND RESEARCH INSTITUTE, BANGALORE.
2. / NAME OF THE INSTITUTE / GOVERNMENTDENTALCOLLEGE AND RESEARCH INSTITUTE, BANGALORE.
3. / COURSE OF STUDY AND SUBJECT / MASTER OF DENTAL SURGERY IN ORTHODONTICS AND DENTOFACIAL ORTHOPEDICS.
4. / DATE OF ADMISSION TO COURSE / 01.06.2009
5. / TITLE OF THE TOPIC:
“SURFACE CHARACTERISTICS AND MECHANICAL PROPERTIES OF SPINNER STRAIGHTENED AND PULSE STRAIGHTENED AUSTRALIAN ORTHODONTIC STAINLESS STEEL WIRES. – A COMPARITIVEINVITRO STUDY. ”
6. / BRIEF RESUME OF THE INTENDED WORK:
6.1 NEED FOR THE STUDY: -
18-8 stainless steel wires are commonly used in orthodonticsas these wires produce less friction due to presence of smooth surface.1Australian wire, a distinctive type of stainless steel has been included in the orthodontic armamentarium for quite some time, but publishedliterature lacks information on fundamental physical and mechanical properties. Studies done on spinner straightened wires show rough surface and increased porosity.2 Surface of thesewires appears to have a striated appearance, which could be due to the drawing process during the manufacture of the wire.2,3Mechanical properties such as modulus of elasticity and ultimate tensile strength of hard drawn Australian orthodontic stainless steel wire have yielded results consistent with those of traditional stainless steel wire.3Whereas pulse straightened wires are claimed to have smooth surface with less resistance and increased tensile strength.4 But there are no studies done on to prove that surface characteristics and mechanical properties of pulse straightened wires are actually better than spinner straightened wires.
Hence, this study focuses onsurface characteristics and mechanical properties of pulse straightened Australian orthodontic stainless steelwiresand its comparison withspinner straightened wires.
7.
/ 6.2 REVIEW OF LITERATURE
1. Tests done by laser spectrometry shows that stainless steel has smoother surface as compared to cobalt chromium, beta titanium and nickel titanium. Stainless steel provides significantly less frictional resistance. Scanning electron microscope also shows decreased surface roughness.1
2. The surface of the spinner straightened wires appears to have a striated appearance, which could be due to the drawing process during the manufacture of the wires. Also, numerous impurities were found plugged on the surface of all spinner straightened wires.2
3. There is little effect of temper or size on hardness and most importantly on modulus of elasticity in Australian orthodontic stainless steel wires as compared to traditional stainless steel wires.3
4. Pulse straightening of Australian orthodontic stainless steel wire produces higher yield strength. It also increases flexibility and resiliency.4
6.3OBJECTIVES OF THE STUDY: -
- To compare mechanical properties namely ultimate tensile strength and modulus of elasticity of spinner straightened and pulse straightened Australian orthodontic stainless steel wire.
- To compare surface characteristics of spinner straightened and pulse straightened Australian orthodontic stainless steel wire using scanning electron microscope.
7.1 SOURCES OF THE DATA.
Wires to be used are:-
- Spinner straightened 0.016 special plus Australian orthodontic stainless steel wire.
- Spinner straightened 0.016 premium plus Australian orthodontic stainless steel wire.
- Pulse straightened 0.016 special plus Australian orthodontic stainless steel wire.
- Pulse straightened 0.016 premium plus Australian orthodontic stainless steel wire.
8. / 7.2 METHODS OF COLLECTION OF DATA.
To test various properties wires are grouped as follows:-
Group 1
1. Spinner straightened 0.016 special plus Australian orthodontic stainless steel wire.
2. Spinner straightened 0.016 premium plus Australian orthodontic stainless steel wire.
Group 2
1. Pulse straightened 0.016 special plus Australian orthodontic stainless steel wire.
2. Pulse straightened 0.016 premium plus Australian orthodontic stainless steel wire
10Specimens of each wire will be taken for this study and subjected to universal testing machine (Instron). Deflection obtained from the stress – strain graph will be used to find the values of ultimate tensile strength and modulus of elasticity. Values obtained on mechanical properties of wires in one group will be compared with second group using statistical analysis by t- test.
Wires in each group will also beobserved under scanning electron microscope for surface characteristics.
7.3 Does the study require any investigations or interventions to be conducted
on patients or other humans or animals?
No
7.4 Has ethical clearance been obtained from your institution in case of 7.3?
Not applicable
LIST OF REFERENCES:
1. Hunt NP, Cunningham SJ, Golden CG, Sherif M. An investigation into the effects of polishing on surface hardness and corrosion of orthodontic archwires. Angle Orthod. 1999; 69: 433–440.
2. Acharya KA, Jayade VP. Metallurgic properties of stainless steel orthodontic archwires: a comparative study. TrendsBiomater Artif Organs. 2005; 18: 125–136
3. Pelsue BM, Zinelis Spiros, Bradley T. Gerard, Berzins DW, Eliades Theodore, Eliades George. Structure, Composition, and Mechanical Properties of Australian Orthodontic Wires. Angle Orthod. 2009; 79: 97–101.
4. Wilcock AJ. jr. J clin orthod. Interviews, On Orthodontic Wires.1988;22: 484-489.
9. / SIGNATURE OF THE CANDIDATE
10. / REMARKS OF THE GUIDE / THIS STUDY IS NOT DONE PREVIOUSLY IN THE DEPARTMENT.
11. / NAME AND DESIGNATION OF
11.1 GUIDE
11.2 SIGNATURE / DR. SHASHIKALAKUMARI V.
PROFESSOR AND HEAD,
DEPARTMENT OF ORTHODONTICS AND DENTOFACIAL ORTHOPEDICS,
GOVERNMENTDENTALCOLLEGE AND RESEARCH INSTITUTE,
BANGALORE.
11.3 HEAD OF THE DEPARTMENT
11.4 SIGNATURE / DR. SHASHIKALAKUMARI V.
12. / 12.1 REMARK OF THE CHAIRMAN AND PRINCIPAL
12.2 SIGNATURE
1