الفهرس 
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Abstract
Summary and Conclusion
In the current study Er:YAG and Er,Cr:YSGG were used for debonding of
polycrystalline ceramic brackets and their effect on adhesive remnant index (ARI)
and enamel surface roughness (ESR) were evaluated and compared to the
conventional debonding method.
Sixty polycrystalline ceramic brackets were bonded to 60 premolars
extracted for orthodontic purposes.
The teeth were divided into 3 groups. The first group was considered as the
control group and no laser application was performed. The other two groups were
considered as test groups and laser application was performed.
group 1: consisted of 12 premolars that were debonded with a debonding
plier.
group 2: consisted of 24 premolars that were debonded with Er,Cr:YSGG
laser and was divided into two subgroups 12 brackets in each:
group 2A: The samples were irradiated with Er,Cr:YSGG laser at
power 9 W.
group 2B: The samples were irradiated with Er,Cr:YSGG laser at
power 6 W.
Summary and Conclusion
55
group 3: consisted of 24 premolars that were debonded with Er:YAG laser and
was divided into two subgroups, 12 brackets in each:
group 3A: The samples were irradiated with Er:YAG laser at power 9 W.
group 3B: The samples were irradiated with Er:YAG laser at power 6 W.
The debonded samples were evaluated by scanning electron microscope
(SEM) at 20x magnification to assess the ARI score. The ARI score classification
was:
- 0, No adhesive remained on the enamel surface.
- 1, Less than half of the adhesive remained on the tooth surface.
- 2, More than half of the adhesive remained on the tooth surface.
- 3, All the adhesive remained on the tooth surface.
After removing all the adhesive remnants at the site of debonding in all
groups with a tungsten carbide bur at high speed followed by polishing with
pumice and polishing brush at low speed, enamel surface roughness was evaluated
by SEM at 60x magnifications. The micrographs were interpreted and classified
according into the following:
- 0, Enamel surface free from cracks or tear-outs (no damage).
- 1, Enamel surface with cracks.
- 2, Enamel surface with tear-outs.
- 3, Enamel surface with cracks and tear-outs.
Summary and Conclusion
56
Within the limitations of the current study, the following was concluded:
1. Under the inquired parameters, both Er,Cr:YSGG and Er:YAG lasers can
effectively debond polycrystalline ceramic brackets without using any
additional forces.
2. Using of Er,Cr:YSGG laser at 9W can decrease the chairside time for
ceramic brackets debonding by decreasing the need for post-debond enamel
finishing.
3. Both Er,Cr:YSGG and Er:YAG laser debonding decreases the risk of enamel
damage compared to the conventional method