“COMPARISON OF LIGHT EMITTING
DIODE CURING UNIT AND HALOGEN
BASED LIGHT CURING UNIT FOR THE
POLYMERIZATION OF ORTHODONTIC
...
Introduction
 The development of firm attachment of
brackets to the teeth is one of the
prominent milestones in the ortho...
 In orthodontics, bonding with light
activated system is popular because the
extended working time allows for
precise bra...
Currently four different technologies
are available for curing of dental
composites by light.
 Halogen lamps
 Plasma arc...
 In 1995, Mills et al proposed solid state
light emitting diode for the
polymerization of light activated dental
material...
 The spectral output of gallium nitride
blue LED falls conveniently within the
absorption spectrum of camphoroquinone
pho...
www.indiandentalacademy.com
www.indiandentalacademy.com
 The purpose of this study is to
compare the shear bond strength
of orthodontic brackets bonded to
teeth with conventiona...
 To compare the shear bond strength
of orthodontic brackets bonded to
teeth with conventional halogen light
curing unit a...
Materials;
 Fifty extracted human bicuspid teeth
 Distilled water
 Pumice and rubber prophylactic cups
 Orthodontic me...
METHOD :
A. Teeth:
Fifty human bicuspid teeth extracted in
the Department of Oral Surgery, College
of Dental Sciences, Dav...
The criteria for tooth selection included;
 Intact buccal enamel
 Not subjected to any pretreatment
chemical agent
 No ...
The teeth thus collected were randomly
divided into 2 groups of 25 each and
embedded in yellow and blue self curing
acryli...
www.indiandentalacademy.com
Cleaning and Etching :
The teeth were cleaned and polished with
pumice and rubber prophylactic cups. The
buccal surface of...
A light cured adhesive primer
(Transbond XT, 3M Unitek) was placed
on the etched enamel surface, lightly air
thinned and p...
 Brackets :
Premolar brackets of 0.022” slot MBT prescription
(3M-Unitek Gemini series) were used (Fig. 4). The
surface a...
Bonding Procedure:
The two groups were bonded in exactly the same
manner with the exception of the light source.
 Group 1...
 Group 2 (Colour code: Blue) : 25 teeth were
bonded using LED light curing unit (3M-ESPE
Elipar Freelight 2) .
www.indian...
 The bracket adhesive interface was
cured for 20 seconds on the mesial side
of the bracket and for 20 seconds on
the dist...
Technical Details
 The 3M ESPE Elipar 2500 halogen curing light
produce high intensity visible blue light in the
400 to 5...
 A single high intensity LED generates
light in the Elipar Freelight 2 LED
curing light. In contrast to
conventioned LED‟...
 Dissipation of heat generated by the
LED‟s during operation is crucial for
durabality of LED based systems. With
the Eli...
Shear Bond Strength Testing Procedure :
 Shear bond strength testing was done using a
Hounsfield universal testing machin...
 The test samples were stressed for debonding at a
crosshead speed of 1 mm/min until the bracket
debonded.
www.indiandent...
Adhesive Remnant Score;
 The amount of adhesive remaining on the tooth was
evaluated using a stereomicroscope (Olympus SZ...
5 = No composite remained on the enamel
4 = Less than 10%of composite remained on
the enamel
3 = Greater than 10% & less t...
Statistical Analysis :
 The mean and standard deviations were
calculated for the shear bond strengths of
the two groups. ...
Results
The students„t‟ test revealed that Group
– I – Halogen based LCU (Mean 8.89
2.46) and Group II – LED LCU (Mean
8.3...
ARI SCORES
It was found that there were no
significant differences in the debonding
characteristics of the two groups with...
Graph 1 : SHEAR BOND STRENGTH
8.89
8.30
0.0
2.0
4.0
6.0
8.0
10.0
12.0
Group I Group II
MeanBS+/-sd(MPa)
www.indiandentalac...
5
6
8
7
11
7
1
4
0
1
0
2
4
6
8
10
12
No.ofsamples
Score 1 Score 2 Score 3 Score 4 Score 5
A R I Scores
Graph 2 : A R I Sco...
Discussion
The most popular method of delivering blue
light has been with halogen based light curing
units. Halogen bulbs ...
 Despite their popularity, halogen bulbs have
several short comings. Halogen bulbs have an
effective lifetime of approxim...
 In contrast to halogen, LED‟s, produce visible
light by quantum mechanic effects. LED‟s
comprise a combination of 2 diff...
 In contrast to halogen, LED‟s produce light
with a narrow spectral distribution. This is
the main difference between lig...
 The LED light used in this study (3M ESPE Elipar,
Freelight 2) has a single high intensity LED. In
contrast to conventio...
 The ARI‟s suggested that most of the
composite remained on the tooth after
bracket debonding, regardless of light curing...
 With comparable shear bond strength
of the LED LCU‟s with the halogen LCU‟s
as found in this study the LED‟s have
certai...
Conclusion
Based on the recorded data and the statistical
analysis the following conclusions were drawn: -
 There is no s...
www.indiandentalacademy.com
For more details please visit
www.indiandentalacademy.com
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Comparison of light emitting diode curing unit and halogen based light curing unit for the polyme /certified fixed orthodontic courses by Indian dental academy

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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078

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Comparison of light emitting diode curing unit and halogen based light curing unit for the polyme /certified fixed orthodontic courses by Indian dental academy

  1. 1. “COMPARISON OF LIGHT EMITTING DIODE CURING UNIT AND HALOGEN BASED LIGHT CURING UNIT FOR THE POLYMERIZATION OF ORTHODONTIC RESINS – AN IN VITRO STUDY ” Title: INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  2. 2. Introduction  The development of firm attachment of brackets to the teeth is one of the prominent milestones in the orthodontic field as it enables efficient movement of the teeth. Firm attachment was initially achieved by cementing bands on all the teeth. www.indiandentalacademy.com
  3. 3.  In orthodontics, bonding with light activated system is popular because the extended working time allows for precise bracket placement and ease of manipulation. Once the bracket is situated at the desired location rapid set is accomplished through photo activation. www.indiandentalacademy.com
  4. 4. Currently four different technologies are available for curing of dental composites by light.  Halogen lamps  Plasma arc lamps  Lasers  LED www.indiandentalacademy.com
  5. 5.  In 1995, Mills et al proposed solid state light emitting diode for the polymerization of light activated dental materials. Rather than a hot filament as used in halogen bulbs, LED‟s use junctions of doped semiconductors (p-n junctions) for the generation of light. www.indiandentalacademy.com
  6. 6.  The spectral output of gallium nitride blue LED falls conveniently within the absorption spectrum of camphoroquinone photo-initiator (400-500 nm) present in light activated dental materials, so that no filters are required in LED LCU‟s.  Furthermore LED‟s have an expected lifetime of several thousand hours without significant degradation of light flux over time. www.indiandentalacademy.com
  7. 7. www.indiandentalacademy.com
  8. 8. www.indiandentalacademy.com
  9. 9.  The purpose of this study is to compare the shear bond strength of orthodontic brackets bonded to teeth with conventional halogen light curing unit and commercial LED light curing unit. www.indiandentalacademy.com
  10. 10.  To compare the shear bond strength of orthodontic brackets bonded to teeth with conventional halogen light curing unit and commercial LED light curing unit.  To determine the site of bond failure. Objectives www.indiandentalacademy.com
  11. 11. Materials;  Fifty extracted human bicuspid teeth  Distilled water  Pumice and rubber prophylactic cups  Orthodontic metal brackets  Light emitting diode-curing unit(3M ESPE Elipar Freelight2)  Halogen based light curing unit(3M ESPE Elipar 2500)  Transbond XT light cure adhesive (3M-Unitek)  Mounting jig  Self cure acrylic  Universal testing machine connected with computer. www.indiandentalacademy.com
  12. 12. METHOD : A. Teeth: Fifty human bicuspid teeth extracted in the Department of Oral Surgery, College of Dental Sciences, Davangere, for orthodontic purposes were collected and stored in distilled water. www.indiandentalacademy.com
  13. 13. The criteria for tooth selection included;  Intact buccal enamel  Not subjected to any pretreatment chemical agent  No caries  No cracks caused by the pressure of extraction forceps. www.indiandentalacademy.com
  14. 14. The teeth thus collected were randomly divided into 2 groups of 25 each and embedded in yellow and blue self curing acrylic upto the level of the cemento- enamel junction. The labial surfaces of the teeth were kept perpendicular to the bottom surface of the mold. www.indiandentalacademy.com
  15. 15. www.indiandentalacademy.com
  16. 16. Cleaning and Etching : The teeth were cleaned and polished with pumice and rubber prophylactic cups. The buccal surface of each tooth was etched for 30 seconds with 37% phosphoric acid gel3. Each tooth was then rinsed with a water spray for 20 seconds and dried with oil free air for 10 seconds3. The buccal enamel surface of the etched teeth appeared chalky white. www.indiandentalacademy.com
  17. 17. A light cured adhesive primer (Transbond XT, 3M Unitek) was placed on the etched enamel surface, lightly air thinned and polymerized for 10 seconds as recommended by the manufacturer. www.indiandentalacademy.com
  18. 18.  Brackets : Premolar brackets of 0.022” slot MBT prescription (3M-Unitek Gemini series) were used (Fig. 4). The surface area of the bracket base was 10.61 mm2 as described by the manufacturer. www.indiandentalacademy.com
  19. 19. Bonding Procedure: The two groups were bonded in exactly the same manner with the exception of the light source.  Group 1 (Colour code: Yellow) : 25 teeth were bonded using conventional halogen based light curing unit (3M-ESPE Elipar 2500) www.indiandentalacademy.com
  20. 20.  Group 2 (Colour code: Blue) : 25 teeth were bonded using LED light curing unit (3M-ESPE Elipar Freelight 2) . www.indiandentalacademy.com
  21. 21.  The bracket adhesive interface was cured for 20 seconds on the mesial side of the bracket and for 20 seconds on the distal side, for a total cure time of 40 seconds. www.indiandentalacademy.com
  22. 22. Technical Details  The 3M ESPE Elipar 2500 halogen curing light produce high intensity visible blue light in the 400 to 500 mm wavelength.  The Elipar 2500 light has an optical filter which reduces radiation above 520 mm. A 75 watt bulb is supplied in the unit. The bulb has a minimum average life of 4000 cycles at 20 seconds each cycle (average lifetimes of approximately 23 hours) . www.indiandentalacademy.com
  23. 23.  A single high intensity LED generates light in the Elipar Freelight 2 LED curing light. In contrast to conventioned LED‟s high intensity LED‟s use a substantially larger semiconductor crystal which increases both the illuminated area and light intensity www.indiandentalacademy.com
  24. 24.  Dissipation of heat generated by the LED‟s during operation is crucial for durabality of LED based systems. With the Elipar Freelight 2 LED curing light, heat is dissipated by a heat sink of highly thermally conductive aluminium integrated in the housing. This kind of heat management is possible only with the moderate amount of heat produced by the LED, which represent less than 5% of the amount produced by the halogen lamp www.indiandentalacademy.com
  25. 25. Shear Bond Strength Testing Procedure :  Shear bond strength testing was done using a Hounsfield universal testing machine which was connected to a digital meter and the debonding force was recorded automatically in Kgf. www.indiandentalacademy.com
  26. 26.  The test samples were stressed for debonding at a crosshead speed of 1 mm/min until the bracket debonded. www.indiandentalacademy.com
  27. 27. Adhesive Remnant Score;  The amount of adhesive remaining on the tooth was evaluated using a stereomicroscope (Olympus SZX12) . The amount of adhesive remaining was scored on the basis of a modified Adhesive Remnant Index (ARI) . www.indiandentalacademy.com
  28. 28. 5 = No composite remained on the enamel 4 = Less than 10%of composite remained on the enamel 3 = Greater than 10% & less than 90% of composite remained on the enamel 2 = Greater than 90% of composite remained on the enamel 1 = All of the composite with the impression of the bracket base remained on the enamel www.indiandentalacademy.com
  29. 29. Statistical Analysis :  The mean and standard deviations were calculated for the shear bond strengths of the two groups. Students „t‟ test was used to compare the shear bond strength of the two groups and the Mann-Whitney test was performed to compare the ARI scores of both the groups. A p-value of less than 0.05 was considered for statistical significance. www.indiandentalacademy.com
  30. 30. Results The students„t‟ test revealed that Group – I – Halogen based LCU (Mean 8.89 2.46) and Group II – LED LCU (Mean 8.30 1.51) exhibited almost the same bond strengths and the difference between the two groups is not significant. (P>0.05) www.indiandentalacademy.com
  31. 31. ARI SCORES It was found that there were no significant differences in the debonding characteristics of the two groups with the majority of the bond failures occurring within the adhesive www.indiandentalacademy.com
  32. 32. Graph 1 : SHEAR BOND STRENGTH 8.89 8.30 0.0 2.0 4.0 6.0 8.0 10.0 12.0 Group I Group II MeanBS+/-sd(MPa) www.indiandentalacademy.com
  33. 33. 5 6 8 7 11 7 1 4 0 1 0 2 4 6 8 10 12 No.ofsamples Score 1 Score 2 Score 3 Score 4 Score 5 A R I Scores Graph 2 : A R I Scores Group I Group II www.indiandentalacademy.com
  34. 34. Discussion The most popular method of delivering blue light has been with halogen based light curing units. Halogen bulbs generate light when electric energy heats a small tungsten filament to high temperatures. Most of the energy put into the halogen system is charged into heat but a small portion is given off as light. www.indiandentalacademy.com
  35. 35.  Despite their popularity, halogen bulbs have several short comings. Halogen bulbs have an effective lifetime of approximately 100 hours. High heat is generated degrading the components of the halogen bulb over time  The lamp reflector may lose its reflector properties because of loss of reflective material, or deposition of surface impurities. www.indiandentalacademy.com
  36. 36.  In contrast to halogen, LED‟s, produce visible light by quantum mechanic effects. LED‟s comprise a combination of 2 different semiconductors, the „n-doped‟ and the „p- doped‟ type. N-doped semiconductors have an excess of electrons while P-doped semiconductors require electrons, resulting in electron „holes‟. www.indiandentalacademy.com
  37. 37.  In contrast to halogen, LED‟s produce light with a narrow spectral distribution. This is the main difference between light produced by LED‟s and other light sources, as lights of selected wavelengths can be preferentially produced using LED‟s with appropriate band gap energies. The spectral output of gallium nitride blue LED‟s falls conveniently within the absorption spectrum of the comphoroquinone photoinitiator (400-500 nm) present in light activated dental materials. www.indiandentalacademy.com
  38. 38.  The LED light used in this study (3M ESPE Elipar, Freelight 2) has a single high intensity LED. In contrast to conventional LED‟s a high intensity LED uses a substantially larger semiconductor crystal, which increases both the illuminated area and the light intensity.  In this study it was found that the shear bond strength of the bracket bonded by the LED LCU containing a single LED was comparable to the shear bond strength of brackets bonded with halogen LCU‟s(8.30+-1.51 and 8.89+-2.46 respectively).  It has been suggested that bond strengths between 8 and 9 MPa are sufficient to withstand normal orthodontic forces www.indiandentalacademy.com
  39. 39.  The ARI‟s suggested that most of the composite remained on the tooth after bracket debonding, regardless of light curing type.  The present study brings into significance the fact that even though it has been previously stated by Fujibayashi & Dunn & Bush that lower the number of LED‟s in the LCU the lower would be the performance, the single LED LCU that was used in the present study has given comparable bond strengths. www.indiandentalacademy.com
  40. 40.  With comparable shear bond strength of the LED LCU‟s with the halogen LCU‟s as found in this study the LED‟s have certain advantages over halogen LCU‟s. They are cordless, smaller and lighter with estimated lifetime of over 10000 hrs. Additionally they have low maintenance costs, and half the heat production of halogen lights. www.indiandentalacademy.com
  41. 41. Conclusion Based on the recorded data and the statistical analysis the following conclusions were drawn: -  There is no statistically significant difference in the shear bond strength of the two groups.  However, since the LED Light Curing Unit used in this study contained only a single LED which is a technological advancement over the previous LED Light Curing Units containing multiple LED‟s the comparable bond strengths become significant.  The ARI scores showed no significant difference www.indiandentalacademy.com
  42. 42. www.indiandentalacademy.com For more details please visit www.indiandentalacademy.com

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