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. 2013 Jul;2(3):87-94.
doi: 10.4103/2278-0203.119680.

Recycling stainless steel orthodontic brackets with Er:YAG laser - An environmental scanning electron microscope and shear bond strength study

Prince K Chacko  1 , Jithesh Kodoth  1 , Jacob John  1 , Kishore Kumar  2
Affiliations

Recycling stainless steel orthodontic brackets with Er:YAG laser - An environmental scanning electron microscope and shear bond strength study

Prince K Chacko et al. J Orthod Sci. 2013 Jul.

Abstract

Aim: TO DETERMINE THE EFFICIENCY OF ERBIUM: Yttrium aluminum garnet (Er:YAG) laser with Environmental Scanning Electron Microscope (ESEM) and shear bond strength analysis as a method of recycling stainless steel orthodontic brackets and compare with other methods of recycling.

Materials and methods: Eighty samples of extracted premolar teeth bonded to SS brackets were tested for rebonded shear bond strength after recycling by four methods and compared with a control group of 20 samples. These 80 samples were randomized into four groups which were recycled by four methods, namely, sandblasting, thermal method, adhesive grinding by tungsten carbide bur, and Er: YAG laser method. After recycling, ESEM and shear bond strength analysis were used to analyze the efficiency of the recycling methods.

Results: ER: YAG laser group was found to be having the greatest bond strength among the recycled brackets (8.33±2.51 followed by the sandblasting at 6.12±1.12 MPa, thermal and electropolishing at 4.44±0.95 MPa, and lastly the adhesive grinding method at 3.08±1.07 MPa. The shear bond strength of Er: YAG laser group was found to be having no statistically significant difference with that of the control group (P>0.05 and had statistical signifance with sandblasting, thermal and electropolishing and adhesive grinding groups at P>0.001. ESEM analysis showed complete removal of adhesive from the brackets recycled with Er: YAG laser which mimicked that of the control group.

Conclusion: ER: YAG laser (2940 nm) was found to be the most efficient method for recycling, followed by the sandblasting, thermal, and the tungsten carbide methods, which had the least shear bond strength value and is not fit for clinical usage.

Keywords: Bond strength; environmental scanning electron microscope; erbium: yttrium aluminum garnet laser; orthodontic brackets; recycling.

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Conflict of interest statement

Conflict of Interest: None declared.

Figures

Figure 1
Figure 1
Sample used in the study
Figure 2
Figure 2
Lloyd universal testing machine
Figure 3
Figure 3
Sandblasting done
Figure 4
Figure 4
Burning old bonding material
Figure 5
Figure 5
Electropolishing
Figure 6
Figure 6
Adhesive grinding using tungsten carbide bur
Figure 7
Figure 7
Er: YAG laser used
Figure 8
Figure 8
Recycling with laser
Figure 9
Figure 9
Philips XL 30 ESEM
Figure 10
Figure 10
Removing adhesive from tooth
Figure 11
Figure 11
ESEM picture of bracket recycled by sandblasting method
Figure 12
Figure 12
ESEM picture of bracket recycled by thermal and electropolishing method
Figure 13
Figure 13
ESEM picture of bracket recycled by tungsten carbide method
Figure 14
Figure 14
ESEM picture of bracket recycled by Er: YAG laser
Figure 15
Figure 15
ESEM picture of the control group
See this image and copyright information in PMC

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