Background:
Titanium is not bioactive and does not promote new bone formation at the early stages of healing. Thus, different strategies for attaching functional groups to titanium has been proposed to enhance the specific cellular responses. In this way, free amino groups exposed onto the titanium surface can protonate at physiological conditions, which would change the surface charge from negative of titanium oxide to positive of amino-functionalized surface. Consequently, a change in the electrostatic interactions between the blood plasma proteins and the surface would influence the bone formation process.
Aim/Hypothesis:
The aim in the present study was to investigate the influence of surface amino-functionalization on bone formation around titanium implants.
Material and Methods:
Titanium grade 4 threaded implants (3.75 × 6 mm) were hydroxylated by a solution of sulfuric acid and hydrogen peroxide for 1 h at room temperature and immediately amino-functionalized using 3-aminopropyltriethoxysilane (APTES). The discs were washed in toluene and acetone before being sterilized by 25 kGy gamma radiation. The control group received only the hydroxylation treatment to present the same surface topography as the test group. The surface was evaluated by scanning electron microscopy (SEM), white light interferometer and atomic force microscopy (AFM). The chemical composition was identified by x-ray photoelectron spectroscopy (XPS). The implants were inserted in a total of 10 New Zealand White rabbits (9 months of age) after approval of the local ethical committee. Each rabbit received one implant in each distal femoral metaphysis and two in each proximal tibia metaphysis for a total of 3 experimental and 3 control implants randomly distributed in each animal. The animals were sacrificed after 3 and 6 weeks of healing (n = 5) with an overdose of pentobarbital. The implants and the surrounding bone were removed and fixed with 4% neutral buffered formaldehyde before being embedded in light curing resin. The midline section of each implant was stained by toluidine blue and the bone-to-implant contact (BIC) was measured by a blind examiner. The data was analyzed by the t test at a significance level of 5%.
Results:
SEM images showed a morphology compatible to acid etched surfaces, due to the hydroxylation treatment with sulfuric acid, on both groups. Interferometer and AFM analyzes revealed similar micro- and nano-roughness, respectively (p > 0.05). Small signals of nitrogen and silicon were detected in the XPS diffractograms, indicating the presence of a submonolayer to monolayer of APTES on the amino-functionalized group. No inflammatory response or adverse reaction was seen around the implants. The implant site in the femur consisted mainly of trabecular bone whereas tibia sites were characterized by a cortical layer of 1.5 mm in height. After 3 weeks, both implants showed typical endosteum reaction leading to new bone down growth from the cortical layer and after 6 weeks of healing, the newly formed mineralized tissue contained osteocytes and osteoblasts, indicating a continuous mineralization process. Similar BIC values were identified for both implants groups after 3 and 6 weeks (p > 0.05).
Conclusions and clinical implications:
It was possible to conclude that the amino-functionalization did not reflect in higher bone formation after 3 and 6 weeks of healing.
Background:
Titanium is not bioactive and does not promote new bone formation at the early stages of healing. Thus, different strategies for attaching functional groups to titanium has been proposed to enhance the specific cellular responses. In this way, free amino groups exposed onto the titanium surface can protonate at physiological conditions, which would change the surface charge from negative of titanium oxide to positive of amino-functionalized surface. Consequently, a change in the electrostatic interactions between the blood plasma proteins and the surface would influence the bone formation process.
Aim/Hypothesis:
The aim in the present study was to investigate the influence of surface amino-functionalization on bone formation around titanium implants.
Material and Methods:
Titanium grade 4 threaded implants (3.75 × 6 mm) were hydroxylated by a solution of sulfuric acid and hydrogen peroxide for 1 h at room temperature and immediately amino-functionalized using 3-aminopropyltriethoxysilane (APTES). The discs were washed in toluene and acetone before being sterilized by 25 kGy gamma radiation. The control group received only the hydroxylation treatment to present the same surface topography as the test group. The surface was evaluated by scanning electron microscopy (SEM), white light interferometer and atomic force microscopy (AFM). The chemical composition was identified by x-ray photoelectron spectroscopy (XPS). The implants were inserted in a total of 10 New Zealand White rabbits (9 months of age) after approval of the local ethical committee. Each rabbit received one implant in each distal femoral metaphysis and two in each proximal tibia metaphysis for a total of 3 experimental and 3 control implants randomly distributed in each animal. The animals were sacrificed after 3 and 6 weeks of healing (n = 5) with an overdose of pentobarbital. The implants and the surrounding bone were removed and fixed with 4% neutral buffered formaldehyde before being embedded in light curing resin. The midline section of each implant was stained by toluidine blue and the bone-to-implant contact (BIC) was measured by a blind examiner. The data was analyzed by the t test at a significance level of 5%.
Results:
SEM images showed a morphology compatible to acid etched surfaces, due to the hydroxylation treatment with sulfuric acid, on both groups. Interferometer and AFM analyzes revealed similar micro- and nano-roughness, respectively (p > 0.05). Small signals of nitrogen and silicon were detected in the XPS diffractograms, indicating the presence of a submonolayer to monolayer of APTES on the amino-functionalized group. No inflammatory response or adverse reaction was seen around the implants. The implant site in the femur consisted mainly of trabecular bone whereas tibia sites were characterized by a cortical layer of 1.5 mm in height. After 3 weeks, both implants showed typical endosteum reaction leading to new bone down growth from the cortical layer and after 6 weeks of healing, the newly formed mineralized tissue contained osteocytes and osteoblasts, indicating a continuous mineralization process. Similar BIC values were identified for both implants groups after 3 and 6 weeks (p > 0.05).
Conclusions and clinical implications:
It was possible to conclude that the amino-functionalization did not reflect in higher bone formation after 3 and 6 weeks of healing.
Background:
Titanium is not bioactive and does not promote new bone formation at the early stages of healing. Thus, different strategies for attaching functional groups to titanium has been proposed to enhance the specific cellular responses. In this way, free amino groups exposed onto the titanium surface can protonate at physiological conditions, which would change the surface charge from negative of titanium oxide to positive of amino-functionalized surface. Consequently, a change in the electrostatic interactions between the blood plasma proteins and the surface would influence the bone formation process.
Aim/Hypothesis:
The aim in the present study was to investigate the influence of surface amino-functionalization on bone formation around titanium implants.
Material and Methods:
Titanium grade 4 threaded implants (3.75 × 6 mm) were hydroxylated by a solution of sulfuric acid and hydrogen peroxide for 1 h at room temperature and immediately amino-functionalized using 3-aminopropyltriethoxysilane (APTES). The discs were washed in toluene and acetone before being sterilized by 25 kGy gamma radiation. The control group received only the hydroxylation treatment to present the same surface topography as the test group. The surface was evaluated by scanning electron microscopy (SEM), white light interferometer and atomic force microscopy (AFM). The chemical composition was identified by x-ray photoelectron spectroscopy (XPS). The implants were inserted in a total of 10 New Zealand White rabbits (9 months of age) after approval of the local ethical committee. Each rabbit received one implant in each distal femoral metaphysis and two in each proximal tibia metaphysis for a total of 3 experimental and 3 control implants randomly distributed in each animal. The animals were sacrificed after 3 and 6 weeks of healing (n = 5) with an overdose of pentobarbital. The implants and the surrounding bone were removed and fixed with 4% neutral buffered formaldehyde before being embedded in light curing resin. The midline section of each implant was stained by toluidine blue and the bone-to-implant contact (BIC) was measured by a blind examiner. The data was analyzed by the t test at a significance level of 5%.
Results:
SEM images showed a morphology compatible to acid etched surfaces, due to the hydroxylation treatment with sulfuric acid, on both groups. Interferometer and AFM analyzes revealed similar micro- and nano-roughness, respectively (p > 0.05). Small signals of nitrogen and silicon were detected in the XPS diffractograms, indicating the presence of a submonolayer to monolayer of APTES on the amino-functionalized group. No inflammatory response or adverse reaction was seen around the implants. The implant site in the femur consisted mainly of trabecular bone whereas tibia sites were characterized by a cortical layer of 1.5 mm in height. After 3 weeks, both implants showed typical endosteum reaction leading to new bone down growth from the cortical layer and after 6 weeks of healing, the newly formed mineralized tissue contained osteocytes and osteoblasts, indicating a continuous mineralization process. Similar BIC values were identified for both implants groups after 3 and 6 weeks (p > 0.05).
Conclusions and clinical implications:
It was possible to conclude that the amino-functionalization did not reflect in higher bone formation after 3 and 6 weeks of healing.
Background:
Titanium is not bioactive and does not promote new bone formation at the early stages of healing. Thus, different strategies for attaching functional groups to titanium has been proposed to enhance the specific cellular responses. In this way, free amino groups exposed onto the titanium surface can protonate at physiological conditions, which would change the surface charge from negative of titanium oxide to positive of amino-functionalized surface. Consequently, a change in the electrostatic interactions between the blood plasma proteins and the surface would influence the bone formation process.
Aim/Hypothesis:
The aim in the present study was to investigate the influence of surface amino-functionalization on bone formation around titanium implants.
Material and Methods:
Titanium grade 4 threaded implants (3.75 × 6 mm) were hydroxylated by a solution of sulfuric acid and hydrogen peroxide for 1 h at room temperature and immediately amino-functionalized using 3-aminopropyltriethoxysilane (APTES). The discs were washed in toluene and acetone before being sterilized by 25 kGy gamma radiation. The control group received only the hydroxylation treatment to present the same surface topography as the test group. The surface was evaluated by scanning electron microscopy (SEM), white light interferometer and atomic force microscopy (AFM). The chemical composition was identified by x-ray photoelectron spectroscopy (XPS). The implants were inserted in a total of 10 New Zealand White rabbits (9 months of age) after approval of the local ethical committee. Each rabbit received one implant in each distal femoral metaphysis and two in each proximal tibia metaphysis for a total of 3 experimental and 3 control implants randomly distributed in each animal. The animals were sacrificed after 3 and 6 weeks of healing (n = 5) with an overdose of pentobarbital. The implants and the surrounding bone were removed and fixed with 4% neutral buffered formaldehyde before being embedded in light curing resin. The midline section of each implant was stained by toluidine blue and the bone-to-implant contact (BIC) was measured by a blind examiner. The data was analyzed by the t test at a significance level of 5%.
Results:
SEM images showed a morphology compatible to acid etched surfaces, due to the hydroxylation treatment with sulfuric acid, on both groups. Interferometer and AFM analyzes revealed similar micro- and nano-roughness, respectively (p > 0.05). Small signals of nitrogen and silicon were detected in the XPS diffractograms, indicating the presence of a submonolayer to monolayer of APTES on the amino-functionalized group. No inflammatory response or adverse reaction was seen around the implants. The implant site in the femur consisted mainly of trabecular bone whereas tibia sites were characterized by a cortical layer of 1.5 mm in height. After 3 weeks, both implants showed typical endosteum reaction leading to new bone down growth from the cortical layer and after 6 weeks of healing, the newly formed mineralized tissue contained osteocytes and osteoblasts, indicating a continuous mineralization process. Similar BIC values were identified for both implants groups after 3 and 6 weeks (p > 0.05).
Conclusions and clinical implications:
It was possible to conclude that the amino-functionalization did not reflect in higher bone formation after 3 and 6 weeks of healing.