Download rajiv gandhi university of health sciences, bangalore

RAJIV GANDHI UNIVERSITY OF HEALTH SCIENCES,
BANGALORE, KARNATAKA
ANNEXURE II
PROFORMA FOR REGISTRATION OF SUBJECTS
FOR DISSERTATION
1.
NAME OF THE CANDIDATE
Dr.MANPREET REEN
AND ADDRESS
POST GRADUATE STUDENT,
(in block letters)
DEPARTMENT OF ORTHODONTICS AND
DENTOFACIAL ORTHOPAEDICS.
BAPUJI DENTAL COLLEGE AND
HOSPITAL, DAVANGERE – 577004,
KARNATAKA.
2.
NAME OF THE INSTITUTION
BAPUJI DENTAL COLLEGE AND HOSPITAL,
DAVANGERE-577 004
3.
COURSE OF STUDY AND
MASTER OF DENTAL SURGERY IN
SUBJECT
ORTHODONTICS AND DENTOFACIAL
ORTHOPEDICS
4.
DATE OF ADMISSION TO
28th APRIL 2008
COURSE
5.
TITLE OF THE TOPIC
“COMPARISON OF CURING EFFICACY
OF HIGH POWER HALOGEN CURING
UNIT TO LIGHT EMITTING DIODE AND
CONVENTIONAL HALOGEN ON
BRACKET BOND STRENGTH: –AN IN
VITRO STUDY”
6.
BRIEF RESUME OF THE INTENDED WORK :
6.1 Need for the study :
Composite resin as bonding material was introduced first by Newman in 1965.
Most common of the visible light curing unit is quartz-tungsten-halogen (QTH) light
curing unit. Curing efficacy of conventional halogen lights is limited because 98% of their
radiation is lost as heat. Only part of halogen light spectrum is useful because the
absorption spectrum of camphoroquinone is comparatively narrow. QTH based lights
have limited life span of 50-100hours and need to be replaced every 6 months.
Light emitting diode (LED) use junction of doped semiconductors to generate
light. They have potential life time of over 10,000 hours with relatively little degradation
and are resistant to mechanical shock and vibration. They are relatively inexpensive and
do not generate much heat.
A new high power halogen lamp-Swiss Master can prove to be a cost effective
solution to reducing curing time. The recommended curing times to bond stainless steel
brackets are 6 sec, with caution 3 sec.
The need for the study is to compare efficacy of three visible light curing unitsConventional halogen , Light emitting diode and High power halogen (Swiss Master) on
basis of shear bond strength of light activated composite resin used as orthodontic
adhesive between two bracket groups - conventional uncoated and adhesive precoated.
6.2 Review of literature :
A study was done to evaluate the shear bond strength of adhesive precoated
brackets (APC) and conventional uncoated brackets (Victory) cured with two different
light curing units: conventional halogen and micro-xenon. Sixty bovine permanent
mandibular incisors divided into 4 groups of 15 teeth each were used. Two groups (one
for each type of bracket) were exposed to halogen light for 20 sec and used as control.
Remaining two was cured with micro-xenon for 2 sec. It was concluded that mean shear
bond strength of uncoated brackets cured with conventional halogen was significantly
higher than all other groups tested.1
A study was undertaken to compare, by shear peel testing, the bond strength after
1 and 24 hours of light cured resin(Enlight) and a light cured GIC(Fuji ortho LC) using
various polymerization lamps: halogen, high performance halogen ,xenon and diode; for
direct bonding of brackets. Self curing resin (Concise) was used as control. According to
this study all polymerization lamps achieved the minimum bond strength of 5-8Mpa.
With Enlight LV bond strength was dependent on curing time and on the mode of cure;
highest bond strength values were achieved by 4 sided curing. Halogen lamp achieved
highest bond strength of 10Mpa with curing time of 40 sec. Other lamps showed similar
results. 2
A study to establish the minimum necessary curing time to bond stainless steel
bracket using new intensive LED curing units was undertaken. 75 bovine primary incisors
were divided into 5 equal groups. TransbondTM XT was used to bond stainless steel
brackets. Two groups were bonded using LED curing lamp-Ortholux LED for 5 and 10
sec. Two more groups were bonded using another intensive LED curing device
(Ultralume LED 5) for 5 and 10 sec. A high output halogen lamp (Optilux 501) was used
for 40 sec to bond the final group and it served as a positive control. It was concluded that
when used for 10 sec, the intensive LED curing units achieved sufficient shear bond
strength, comparable with the control. Significantly lower shear bond strength was
observed with cure time of 5 sec.3
A study was done to evaluate high power halogen light(Swiss Master) to estimate the
minimum exposure time necessary to achieve bond strength equivalent to bond strength
obtained with a fast halogen light(Optilux 501). For the study five groups of fifteen
deciduous bovine incisors were bonded with stainless steel brackets by using different
lamps and curing times. It was concluded that high power halogen light minimizes curing
time dramatically without compromising the bond strength of orthodontic brackets.
Exposure to high power halogen light for 6 sec and even 3 sec lead to shear bond strength
equivalent to those achieved after 40 sec of exposure to fast halogen light. In this study
the parameter that allowed reduction in curing time seemed to be the increase in power
density.4
A comparative study was done to test the shear bond strength of precoated and
uncoated ceramic and metal brackets. The adhesive used on precoated brackets was
similar in composition to that used for bonding uncoated brackets with the difference in
percentages of various ingredients incorporated in the material. Eighty five extracted
human molars were used for the study. The findings indicated that 1) Precoated ceramic
brackets had shear bond strengths similar to that provided by Transbond XT adhesive on
uncoated brackets. 2) Precoated metal brackets had significantly lower shear bond
strength than those obtained with Transbond XT on uncoated brackets. Difference in bond
strength was attributed to combined effects of the changes in composition of adhesive
used and in the retention mechanism incorporated in the bracket bases.5
6.3 Objectives of the study :
1. To test the efficacy of three visible light curing units- Conventional halogen, Light
emitting diode and High power halogen light (Swiss Master) on the basis of shear
bond strength of light activated composite resin used as an orthodontic adhesive.
2. To evaluate the shear bond strength between 2 bracket groups: conventional
uncoated and adhesive precoated brackets.
7.
MATERIALS AND METHODS
7.1. Source of data :

Sixty extracted human premolar teeth will be collected from the Department of Oral
Surgery, Bapuji Dental College and Hospital, Davangere.
7.2. Method of collection of data:
Criteria for the selection of sample:
1. Intact buccal enamel with no caries and no cracks due to the pressure of extraction
forceps.
2. Not subjected to any pre treatment chemical agents or bleaching agents.
7.3 Method of study:
1) Sixty extracted human premolar teeth will be divided into 3 groups of 20 teeth each.
Each group will be further sub-divided into two groups:



Group I (n=20) – Cured using conventional halogen light curing unit

Group I A (n=10) – using conventional uncoated brackets

Group I B (n=10) – using adhesive precoated brackets
Group II (n=20) – Cured using light emitting diode curing unit

Group II A (n=10) – using conventional uncoated brackets

Group II B (n=10) - using adhesive precoated brackets
Group III (n=20) – Cured using High power halogen light curing unit

Group III A (n=10) - using conventional uncoated brackets

Group III B (n=10) - using adhesive precoated brackets
Teeth in each group will be mounted vertically on acrylic blocks and will be stored in
distilled water until the experimental procedure is initiated.
2)
The shear bond strength will be measured with Universal Testing Machine after 24
hours of bonding brackets on mounted teeth. Shear force will be applied in
occlusogingival direction, parallel to tooth-bracket interphase. The force necessary to
debond brackets will be recorded.
7.4 STATISTICAL ANALYSIS :
One way ANOVA will be used for multiple comparisons and for group wise
comparison student’s t-test will be used.
7.5 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
7.6 Has ethical clearance been obtained from your institution in case of 7.3
Not applicable
8.
LIST OF REFERENCES :
1) Sfondrini MF, Cacciafesta V, Klersy C. Halogen versus high- intensity light
curing of uncoated and precoated brackets: a shear bond strength study. J Orthod
2002;29:45-50.
2) Wendl B, Droschl H. A comparative in vitro study of the strength of directly
bonded brackets using different curing techniques. Eur J Orthod 2004;26:535544.
3) Mavropoulos A, Staudt CB, Kiliaridis S, Krejci I. Light curing time reduction:
in vitro evaluation of new intensive light emitting diode curing units. Eur J
Orthod 2005;27:408-412.
4) Staudt CB, Mavropoulos A, Bouillaguet S, Kiliaridis S, Krejci I. Light curing
time reduction with a new high power halogen lamp. Am J Orthod Dentofacial
Orthop 2005;128:749-753.
5) Bishara SE, Olsen M, Von Wald L. Comparison of shear bond strength of
precoated and uncoated brackets. Am J Orthod Dentofacial Orthop 1997;112:
617-621.
9.
10
SIGNATURE OF THE CANDIDATE
REMARKS OF THE GUIDE
11
NAME & DESIGNATION.
11.1 GUIDE
Dr. Sunil Sunny
Associate Professor.
Dept of Orthodontics and Dentofacial
Orthopedics
Bapuji Dental College and Hospital,
Davangere- 577 004.
11.2 SIGNATURE
11.3 CO-GUIDE
(if any)
11.4 SIGNATURE
11.5 HEAD OF THE DEPARTMENT
Dr. K . SADASHIVA SHETTY
Professor & Head
Department of Orthodontics and
Dentofacial Orthopedics,
Bapuji Dental College and Hospital,
Davangere - 577 004.
11.6 SIGNATURE
12
REMARKS OF THE CHAIRMAN &
PRINCIPAL
12.1 SIGNATURE
.