[Effect of surface roughness and composition of titanium on proliferation and differentiation of osteoblasts].

PURPOSE: To study the effects of surface roughness and composition of titanium on proliferation and differentiation of osteoblasts. METHODS: Osteoblasts were cultured on 5 commercially pure titanium (cp Ti) substrates of ground (S0), blasted with 108-130 µm(S1), 216-301 µm(S2), 356-411 µm (S3) TiO2 particles and titanium-sprayed plasma(TPS) surfaces. Surfaces prepared by hand grinding with SiC paper of 600 grits served as control (S0). Electron microprobe was used to evaluate the TiO2 film structure of the 5 titanium surfaces. For proliferation and differentiation measurement, osteoblasts were cultured for 1, 3, 5 and 7 days, evaluated by MTT Assay, ALP activity and OC level. SPSS12.0 software package was used for one-way ANOVA. RESULTS: The number of cells was the highest on S3 and TPS surfaces after 1 day culture. The same results were observed after 5 days. On day 3 and 7, S3 surface was the highest(P<0.05). The number of cells on all experimental groups were higher than S0 surfaces at each time point(P<0.05). Increase of ALP activity were detected on S0, S1 and S2 surfaces after 1, 3, 5 days. However, there was no difference between S3 and TPS surfaces(P>0.05). After 7 days, ALP activity increased significantly on TPS surface than on S1 or S2 surfaces. ALP activity on S3 surfaces was the highest(P<0.05). The ALP activity on all experimental groups were higher than S0 surfaces at each time point(P<0.05). An increase in OC production was detected on S0, S1, S2 and S3 surfaces after 1, 3, 5 days. The highest OC production was on S3 surface was on day 7(P<0.05). CONCLUSIONS: It was concluded that for TiO2 blasted surfaces, Ra ranging from 1.260 µm to 3.530 µm would optimize proliferation and differentiation of osteoblasts. Blasting was an effective treatment method for osteointegration in vitro.

[Effect of surface roughness and titanium dioxide layers on commercially pure titanium on attachment of osteoblasts].

OBJECTIVE: To study the effects of surface roughness and titanium dioxide (TiO2) layers on commercially pure titanium (cp-Ti) substrates on attachment of osteoblasts in vitro. METHODS: 250 pure titanium slices were divided into five groups. Osteoblasts were cultured on five cp-Ti substrates of ground, which blasted with 108-130 microm (S1), 216-301 microm (S2), 356-411 microm (S3) TiO2 particles and titanium-sprayed plasma (TPS) surfaces, surfaces prepared by hand grinding with SiC paper to 600 grits served as control (S0). Surface average roughness and the TiO2 film structure was evaluated. For morphology and attachment measurement, osteoblasts were cultured for 1, 4, 12 and 24 h, evaluated by scanning electronic microscope (SEM) observation and MTr assay. RESULTS: Osteoblasts spread well on the titanium surfaces. Further more, osteoblasts spread more well on S3 surfaces. After 1 and 4 h culture, the number of cells on S3 surfaces was the highest (P < 0.05). The number of cells on S3 surfaces was the same (P > 0.05) as TPS surfaces and higher than other groups (P < 0.05) after 12 and 24 h. The number of cells of all experimental groups were higher than S0 surfaces after 4, 12 and 24 h (P < 0.05). CONCLUSION: It was concluded that the coarse TiO2 particles blasted surface would optimize initial osteoblast responses.

[Preparation and properties of chitosan film as a drug sustained-release system].

OBJECTIVE: To develop a best chitosan film for using as a drug sustained-release system through the evaluation of the sustained-release property, degradation property, and cytotoxicity to osteoblast. METHODS: Orthogonal experiments were designed to determine the best combination of chitosan film preparations. Drug release rate was determined with Coomassie brilliant blue G250. In a separate study, chitosan films were placed into the test tubes with buffer solution and 10(7) U/L lysozyme. The degradation rate was calculated. Osteoblasts derived from fetal rat calvarial were cultured on chitosan films. Cell proliferation was tested by methyl thiazolyl tetrazolium (MTT) assay. The relative growth rate was calculated and the cytotoxicity was graded. RESULTS: The best processing condition was 1% acetic acid, chitosan concentration of 2 mg/mL, 6% sodium tripolyphosphate (STPP) concentration, and cross-linking time of one hour. The resulting chitosan film released 33.13% of bovine serum albumin (BSA) within 8 d, 36.73% of BSA within four weeks and the cytotoxicity grade was 0 or 1. CONCLUSION: This chitosan film possesses good sustained release property, and a good degradation rate.

[Effects of TiO2 blasted and acid-etched titanium surfaces on oxide-film and osteoblast].

UNLABELLED: OBJECTIVE To study the effects of TiO2 blasted and acid-etched surfaces of cp-titanium on changing composition of oxide-film and attachment and proliferation of osteoblasts in vitro. METHODS: cp-titanium discs were prepared and divided into 4 groups: TiO2 blasted (SB), sandBlasted and acid-etching (SLA1 and SLA2) and machine-polished surface (S1). Scanning electron microscopy (SEM), X-ray diffraction (XRD) and electron probe microanalysis (EPMA) were used to test surface morphology and composition of oxide-film. Osteoblasts were cultured on the titanium surface of 4 groups. MTT assay was used to measure the attachment and proliferation. RESULTS: In regard to surface roughness, average roughness for SB, SLA1 and SLA2 was obviously higher than S0 Oxygen ratio increased on SB,contrarily, it decreased on SLA. A mixture of anatase and rutile-type crystals were observed in the SB. Smaller anatase were observed in the SLA1 and SLA2. The oxide thickness on SLA surface was thiner than that on the SB surface. Alter 1, 4, 24 hours' culture, the number of osteoblast attachment on SB surfaces was the highest (P < 0.05). The number of cells osteoblast proliferation was the highest on SB after 1, 3, 5 and 7 days' culture (P < 0.05). CONCLUSION: The thickness and chemical composition of oxide film play an important role in osteoblast attachment and proliferation at the same roughness surface. It is concluded that osteobla.st attachment and proliferation are better on SB surfaces than on SLA1 and SLA2 surfaces.

[Effect of different titanium surfaces on F-actin cytoskeleton of osteoblast].

UNLABELLED: OBJECTIVE To evaluate the effects of grooved, alkali- and heat-treated, acid-etched and TiO2 blasted surfaces of titanium substrates on F-actin cytoskeleton of osteoblasts in vitro. METHODS: Osteoblasts derived from fetal rat calvarial were cultured on 6 different commercially pure titanium discs-grooved(G), sandblasted (SB), sand-blasted and acid-etching (SLA) surfaces and alkali- and heat-treated (AH1, AH2, AH3) surfaces. For F-actin cytoskeleton measurement, osteoblasts whose filamentous actin was stained with phalloidin-TRITC were cultured for 1, 2, 4, 12 h, evaluated by CLSM observation. RESULTS: Osteoblasts attached to the different types of surfaces after 1 hour culture were similar. The actin cytoskeleton formed a ring of cortical filaments around the nucleus after 1 hour on SB, AH2, AH3, SLA surfaces. Actin filaments condensed along edges of pits. The actin filaments of seeded cells were spread after 2 h. The actin filaments on G formed bundles around the nucleus. The filaments began to parallel to the grooves. On AH1, the fibres formed a ring of cortical filaments around the nucleus with some cytoplasmic fibres radially oriented. On AH2, AH3, SB, the fibres orignised in a cytoplasmic meshwork with fibres which terminate at the ridge of depressions. The cell were suspending itself over the depressed areas. Actin filaments on SB were distinct and well formed that were oriented paralled to one another and the long axis of cells. After 4 h, actin filaments appeared organised in a parallel to one another and the long axis of cells. After 12 h, the actin filaments on all surfaces were well spread and were oriented paralled to another and to the long axis of the cell. The filaments formed bundles which reached to holes or adhered to the ridge of raised points, suspending cells over depressed areas. CONCLUSION: After 12 h, the actin filaments on all surfaces were well spread and were oriented parallel to another and to the long axis of the cell. It was concluded that F-actin cytoskeleton of osteoblasts were spread best on SB surfaces among all surfaces.

[The morphological study of bone-implant interfaces in vivo].

OBJECTIVE: To evaluate the bone-implant interfaces of two kinds of implants with different surfaces in different time in vivo. METHODS: CDIC and ITI-TPS solid-screw cylinder pure titanium implants were selected and implanted in the regions of posterior molars of rhesus monkeys. 1 month, 2 months, 3 months and 1 year after surgery, the bone-implant interfaces were evaluated respectively through oral examination, X-ray inspection, light microscope and scanning electron microscope (SEM) observation. RESULTS: None of the implants was loose. Soft tissue around implants appeared no inflammation. There were no apparent transparent shadow around the implants interfaces in X-ray photos except little angle-shaped absorption was showed in neck region of CDIC implants of one-month. New bone was observed around implants of one-month through light microscope and SEM. More bone growing around ITI implants were seen than that around CDIC implants except the interfaces of one-year. CONCLUSION: The osseointegration of ITI implants are better than that of CDIC implants during three months after implanting without loading. The bone formation at the interfaces of ITI and CDIC implants has no significant difference after one year without loading.