الفهرس 
LITERATURE REVIEWOnly 14 pages are availabe for public view
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Abstract
Zirconia is a promising alternative to titanium regarding to dental implant field. Implant surface characteristics are considered as factors that affect the rate and extent of the implant bone response as well as the mechanical quality of the bone/implant interface. This study aimed to evaluate the influence of laser and UV surface modification strategies to enhance osseointegration of zirconia implants.
Three different zirconia implant surfaces were tested in this study: 1) zirconia with unmodified surfaces (control), 2) zirconia with Nd:YAG laser modified surfaces, 3)Zirconia with UV light modified surfaces; CAD/ CAM zirconia discs and implant zirconia cylinders were milled and sintered according to manufacturer instructions. Specimens modified with laser were exposed to Nd:YAG laser at wavelength 1064 nm, power 2w, 240 pulses per minute with pulse width 7 ns, repetition rate 10 hz and the distance between laser source and disc is 30 cm for 2 minutes. While zirconia specimens modified with UV were exposed to UV lamp at wavelength 365 nm for 48 hours. Surface roughness topography (Ra) values of all discs were analyzed using confocal laser scanning microscopy and surface wettability was studied using a contact angle rame-hart instrument. For in vivo histological study the zirconia cylinders were inserted into the femur’s heads of rabbits’ models. The osseointegration around the implants in the experimental animals was evaluated by using light microscope.
Confocal laser microscope exhibited the surface roughness (Ra) mean values in micrometer. Nd: YAG laser modified surfaces recorded the significantly highest (Ra) mean value of [0.76um], followed by [0.14um] for UV light modified surfaces, while unmodified surfaces revealed the lowest (Ra) mean value of [0.13um].
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Contact angle mean values were recorded. The highest values were recorded for the control group (131.65) reflecting the lowest surface wettability, followed by laser treated group (84.03) and the UV one revealed the lowest values (71.89) indicating the highest surface wettability.
Histological results after 4 and 8 weeks healing period revealed that laser group showed the best bone formation quality and osseointegration surrounding the zirconia implants compared to other groups.
Laser modification improving the implant osseointegration through generating a pattern of micro- and nano-scale microchannels. These microchannels have been proposed to act as a micromechanical and biologic seal by connecting the attachment of connective tissue and bone. UV light application on zirconia transform the hydrophobic surface property of zirconia to be hydrophilic and thus enhancing the osteoblast response.
Nd:YAG laser and UV modifications succeeded to alter smooth hydrophobic zirconia surfaces to be rough and hydrophilic with enhanced biological performance which was proved with the histological outcomes that displayed enhanced osseointegration features.