| dc.description.abstract | Re-implantation of mini-implants would be financially advantageous in
orthodontics and could encourage an increase in use of these devices. An
analysis of the bacterial contamination after different sterilising methods
has currently not been performed. The aim of this study was to determine
the most effective method in sterilising of orthodontic mini-implants for
re-implantation in the same patient.
The sample included 40 retrieved mini-implants which were collected
from private orthodontists, orthodontic registrars, and a maxillo-facial and
oral surgeon in South Africa after completed use in patients. They were
allocated into groups that underwent different sterilising processes. Gr1
was autoclaved; Gr2 was immersed in 37% phosphoric acid for 10
minutes, followed by being soaked in Milton for 30 minutes; Gr3 was
dipped in 70% ethanol and then flamed in a butane gas burner; and GrC
did not undergo any processing and served as the control.
Bacteria remaining after processing were cultured in Brain Heart Infusion
Medium and incubated at 37 degrees Celsius to determine whether any
bacterial contamination remained on the mini-implant. To investigate the
effects of the sterilising methods on the surface of the mini-implants, they
then underwent scanning electron microscopy analysis to assess amount of
visible tissue remnants which remained on the surface. These miniimplants
were further subjected to energy dispersive spectroscopy (EDS)
to investigate their elemental composition.
All processing methods were able to sterilise the mini-implants tested and
no bacterial growth was present after culturing in Brain Heart Infusion
Medium. There were, however, differences in their surface appearances.
Gr2 displayed the least amount remaining surface remnants (mean 5.21%),
whereas Gr1 (autoclave) and Gr3 (burnt) showed mean of 30.08 and
47.04% tissue remnants on their surfaces respectively.
Titanium, aluminium, vanadium, carbon and oxygen were found on all
surfaces of the groups. Additional elements, namely, calcium, potassium,
sodium, phosphorous, sulphur, silicon, bromine, chlorine, nitrogen, and
magnesium were found in the tissue remnants of all the processing groups.
Sterilising methods autoclave and burning (Gr1 and Gr3), which made use
of heat, had almost double the atomic percentage of carbon. Gr2, etch and
Milton, had the lowest atomic percentage of calcium and none of the mini-implants in this group showed traces of iron, which was present in the
other groups.
Based on the methods tested in this study, Gr2 which involves immersing
the mini-implant in 37% phosphoric acid for 10 minutes, followed by
soaking mini-implant in Milton for 30 minutes is the suggested method of
sterilising mini-implants before re-implantation.
Further studies looking into additional sterilisation methods, possibly with
the use of sonication or scrubbing, are required to draw up protocols on reimplantation
of mini-implants. Additional histological and ion release tests
will also be required to confirm which method of sterilisation will result in
no additional complications in the patient to that of insertion of a new,
unused mini-implant. | |
