|
|
Objectives: To investigate
nickel ion released from
recycled brackets by sandblasting and
|
|
|
|
elemental analysis of bracket base.
Methods:
0.018" and 0.022" metal
orthodontic
|
|
|
|
brackets (Ormco Corp.) for premolars were
used. Group1 was 42 new brackets.
Group 2
|
|
|
|
consisted
of 42 new brackets bonded
to extracted premolars and debonded
by
|
|
|
|
Loyd tesing
machine. The bracket base was cleaned by
a sandblaster
using 50
mm
|
|
|
|
Aluminum Oxide. Group 3
was 41 bond-failure brackets collected from
dental
|
|
|
|
clinics and recycled by the
same sandblasting.
36 brackets of each group were immersed
|
|
|
|
in plastic bottles containing
15 ml. distilled
water and made into six replicates.
The
|
|
|
|
samples were kept in an
incubator at 37deg.C.
8 ml. solution was
collected
from each
|
|
|
|
bottle at the time 0 hr., 24 hrs.,
30, 90 and 180 days; the same amount
of distilled water
|
|
|
|
was replaced at each
collection. Nickel ion was analyzed
by
ICP Atomic Emission
|
|
|
|
Spectrometer. Elemental
analysis of the rest of brackets was
carried out by SEM with
|
|
|
|
dispersive X-ray
spectrometer (EDS). Results:
means
(std.dev.) of nickel ion (mg
/ l)
|
|
|
|
were listed.
|
|
|
|
|
|
|
|
|
Group
|
0
Hr.
|
24
Hrs.
|
30
days
|
90
days
|
180
days
|
|
1
|
0.00
(0.00)
|
4.75
(2.76)
|
11.12
(8.64)
|
19.28
(12.58)
|
37.71
(29.05)
|
|
2
|
0.00
(0.00)
|
5.36
(1.83)
|
19.53
(9.97)
|
23.94
(10.20)
|
39.45
(18.67)
|
|
3
|
0.00
(0.00)
|
0.75
(0.78)
|
4.01
(1.47)
|
4.88
( 1.65)
|
5.27 (
2.28)
|
|
|
|
|
|
|
|
|
Kruskal
Wallis indicated highly significant difference
of nickel ion among the three groups
|
|
|
|
(p£0.001).
Nickel ion from the recycled clinical
bond-failure
brackets
was less than
|
|
|
|
other groups. Elemental
analysis revealed no significant difference
in metal composition
|
|
|
|
of the new and recycled
bracket bases. Conclusions:
nickel ion release from each group
|
|
|
|
increased
over a period of 180 days.
The total nickel ion averaged
did not exceed the
|
|
|
|
recommended daily intake.
Supported
by Srinakarinwirot
University Research
|
|
|
|
Grant
No. 065/2545.
|
|