Zaheer, Naauman
(2020)
The effect of ultraviolet photofunctionalization on titanium implant surface and its related clinical performance.
PhD thesis, Universiti Sains Malaysia.
Abstract
Commercial titanium implants are highly reactive, and it eventually degrades
with time due to accumulation of surface hydrocarbons from surrounding environment,
which ultimately decreases the cellular attachment and bone formation on implant
surface. The surface hydrocarbons can be reduced through ultraviolet (UV) irradiation of
implants also known as photofunctionalization. The aim of the present study was that
which wavelength of ultraviolet (UV) radiation is suitable to induce maximum positive
effects on implant surface and compare it with non-UV irradiated implants. The main
objective of this study was to assess the changes in pore diameter as well as changes in
hydrocarbon levels on the surface of SLA coated titanium implants in laboratory study
following UV irradiation with varying wavelengths. In the clinical part of the study,
changes in marginal bone loss (MBL), bone density and implant stability in the alveolar
bone surrounding the titanium implants were assessed and compared. The laboratory
part of the study was conducted on nine Dio UFII implants with hybrid sandblasted and
acid-etched (SLA) surface treatments, divided equally among three groups. Implants in
control group A were not irradiated, while groups B and C samples were given UVA
(382 nm, 25 mWcm2) and UVC (260 nm, 15 mWcm2) irradiation, respectively. Changes
in pore diameter and the atomic ratio of carbon, titanium, oxygen and on implant
surfaces were analysed and compared among the groups. In the clinical part of the study,
sixty-six implants were placed in systemically healthy participants. Simplerandomization was employed to allocate patients into three groups. In group A (control
group), patients received implants as it is without any intervention, while patients in
group B (UVA group) and C (UVC group) received photofunctionalized implants. The
MBL and bone density in the surrounding bone was evaluated through Cone Beam
Computed Tomography (CBCT) at 8th and 26th week and comparisons were done among
the three groups. It was observed in laboratory part of the study that UVC group showed
more pronounced increase in pore diameter compared to UVA and control group. The
surface carbon content was also considerably reduced, whereas percentages of titanium
and oxygen were enhanced for group C compared to other groups. Meanwhile in the
clinical part of the study, both UVA and UVC treated groups showed minimal MBL
compared to control group. UVC group showed significant improvement in bone density
between 8th and 26th week time. Implant stability was also evaluated at time of
placement of implant fixture (day 0) and after 8th week before functional loading.
Implants irradiated with UVA had relatively significant effect on ISQ level as compared
to control and UVC group. In conclusion, UVC irradiation has the potential to increase
the pore diameter and reduce the surface hydrocarbons, thus inducing more bone
formation around the implant surfaces.
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