Gnathology in implant-supported fixed restoration in edentulous mandible / 华西口腔医学杂志

OBJECTIVE@#This study aims to investigate the occlusal and myoelectric characteristics of implant-supported fixed denture in the mandibular region and provide reference for the design of fixed restoration.@*METHODS@#Sixty edentulous patients with implant-supported fixed denture were selected and divided into three groups: group A, 20 cases with implant-supported fixed restoration in the maxillary region; group B, 20 cases with natural dentition, and group C, 20 cases with removable partial denture. The T-scan 8.0 digital occlusion analysis system was used to evaluate the occlusal characteristics of patients in the three groups at intercuspal, protrusion, and left and right lateral positions. Electromyography was used to analyze the myoelectric amplitude and bilateral asymmetry index of the anterior temporalis and masseter of the three groups in different states such as resting and clenching. The relationship between occlusion and myoelectricity was also investigated.@*RESULTS@#In the occlusion analysis by T-scan, the occlusion time, the balance of left and right bite force, the left and right asymmetry of the occlusion center, the trajectory of central occlusion force, and the disclusion time were higher in group C than in groups A and B (P<0.05). No significant differences were observed in the anterior and posterior asymmetry of the occlusion center and percentage of bite force at anterior region among the three groups. In the analysis of myoelectricity, the myoelectric amplitude at resting state and the asymmetry index of masticatory muscles in group C were higher than those in groups A and B (P<0.05). The myoelectric amplitude during clenching in groups A and B groups was higher than that in group C (P<0.05).@*CONCLUSIONS@#In implant-supported fixed restoration at edentulous mandibular, when maxillary includes the removable partial denture, degree of occlusal instability and left and right asymmetry of occlusion center are greater than those with the natural dentition and implant-supported fixed denture at maxillary. The myoelectricity is closely related to occlusion. The removable partial denture can increase the myoelectric activity and reduce the potential of the masticatory muscle. The asymmetry of bilateral myoelectricity is related to the occlusion imbalance.

Occlusal analysis of implant-supported fixed denture in edentulous patients / 华西口腔医学杂志

OBJECTIVE@#This study aims to evaluate the occlusal characteristics of full edentulous patients with implant-supported prostheses and to provide a reference with the occlusal situation for clinicians.@*METHODS@#A Teetester occlusal analysis system was used with 30 full edentulous patients of implant-supported fixed denture (test group) in comparison with 30 natural dentition (control group). The percentage of occlusal force distribution were measured, as well as the occlusal time at the intercuspal, protrusion, and left and right lateral positions.@*RESULTS@#Compared with control group, the occlusion time, maximum occlusal force in intercuspal of test group significantly reduced (P<0.05); while control group was obviously superior to test group in the left and right bit force degree. Disclusion time in protrusion, occlusion times in lateral positions of test group also significantly reduced (P<0.05). There were no significant differences in average occlusion force, percentage of total force in anterior teeth, and lateral occlusion between test group and control group.@*CONCLUSIONS@#The maximum occlusal force in intercuspal of full edentulous patients with implant-supported prostheses reduce. The occlusal force in protrusive occlusion is concentrated in the front teeth, and the group function occlusion is the main lateral occlusal pattern.

Inhibition of osthole for resorption of rats femur tissue in vitro / 中国骨伤

<p><b>OBJECTIVE</b>To investigate osthole effect on femoral tissue resorption activity of rat in vitro.</p><p><b>METHODS</b>Six SD rats weighted (80 ± 5) g were used to isolate and culture femoral tissue (diaphyses and metaphysis) in vitro. The cultured tissue were devided into control group, estradiol group and osthole group. The femoral tissue was treated with final concentration of 1 x 10(-5) mol/L osthole and 1 x 10(-8) mol/L estradiol culture in vitro at 48 hours after cultured. Tartrate-resistant acid phosphatase (StrACP) activity, glucose and Lactic acid content, StrACP, MCSF (Macrophage colony stimulating factor) and CTSK (Cathepsin K) mRNA was detected by Real-Time RT-PCR were detected.</p><p><b>RESULTS</b>Concetration of Alkaline phosphatase activity were 2226 and 2498 in 1 x 10(-5) mol/L osthole and 1 x 10(-8) mol/L estradiol respectively. As compared with control group, the activity of StrACP of 1 x 10(-5) mol/L osthole and 1 x 10(-8) mol/L estradiol were inhibited at 6, 9, 12 days (P < 0.05); under treatment of in l x 10(-5) mol/L osthole, the content of Lactic acid were increased and the content of glucose were decreased at 3, 6, 9 days (P < 0.05); StrACP, MCSF and CTSK mRNA expression level were inhibited at 6, 9 days (P < 0.05).</p><p><b>CONCLUSION</b>Osthole can inhibit bone resorption and raise the level of nutrition metabolism of femurs tissue.</p>

Establishment of osteoblast primary cilia model removed by chloral hyrate / 中国骨伤

<p><b>OBJECTIVE</b>To establish osteoblast model, primary cilla model was removed by chloral hyrate, observe effects of osteoblast primary cilla moved on enhancing ALP staining and calcified nodules staining in electromagnetic field.</p><p><b>METHODS</b>Three 3-day-old male SD rats weighed between 6 and 9 g were killed, cranial osteoblast was drawed and adherencing cultured respectively. Cells were subcultured and randomly divided into 4 groups until reach to fusion states. The four groups included chloral hydrate non-involved group (control group), 2 mM, 4 mM and 8 mM chloral hydrate group, and cultured in 37 °C, 5% CO2 incubator for 72 h. Morphology of primary cilla was observed by laser confocal scanning microscope, and incidence of osteoblast primary cilia was analyzed by Image-Pro Plus 6.0 software. Cells in the correct concentration group which can removed cillia most effectively were selected and divided into 3 groups, including control group (C), Electromagnetic fields group (EMFs), and EMFs with 4 mM chloral hydrate group. DMEM nutrient solution contained 10%FBS were added into three groups and cultured for 9 days and formation of ALP were observed by histochemical staining of alkaline phosphatase. After 12 days' cultivation, formation of mineralization nodes was observed by alizarin red staining.</p><p><b>RESULTS</b>Compared with control group and 2mM chloral hydrate group,4 mM chloral hydrate group could effectively remove osteoblast primary cilla (P<0.01). Removal of osteoblast primary cilla could weaken the formation of ALP and mineralization nodes in osteoblast in EMFS. Compared with EMFs group, the area of ALP and mineralization nodes in EMFs with 4 mM chloral hydrate group were decreased obviously (P<0.01).</p><p><b>CONCLUSION</b>4mM chloral hydrate could effectively remove osteoblast primary cilia. Primary cilla participate in EMFs promoting formation of ALP and mineralization nodes in osteoblast and provide new ideas for exploring mechanism of EMFs promoting osteoblast maturation and mineralization.</p>

Icariin promote maturation of osteoblasts in vitro by an estrogen-independent mechanism / 中国中药杂志

<p><b>OBJECTIVE</b>To investigate the estrogenic activity of icariin and genistein with estrogen-dependent human breast cancer (MCF-7) cells.</p><p><b>METHOD</b>MCF-7 cells were incubated with media containing 5% charcoal dextran-treated FBS in phenol red-free media for 48 h. CCK-8 kit was used to study the impact of defferent concentration of icariin and genistein on MCF-7 proliferation in vitro. Optimal concentration icariin and genistein were added into medium and total RNA was isolated after 12, 24, 36, 48 h. The gene expression of ERalpha, ERbeta, PS2, and PR were investigated by Real-time RT-PCR Total protein was also isolated and secretion of ERalpha, ERbeta, PS2, and PR were examined by Western blot.</p><p><b>RESULT</b>10 micromol x L(-1) icariin and genistein could promote the proliferation of MCF-7 evidently. However, the ability of genistein to promote the proliferation was better than icariin. With the concentration of 10 micromol x L(-1), genistein group had a stronger expression of ERa, PS2 and PR mRNA levels than icariin while ERbetaexpression had no significant difference in two group. The same effects were detected by western blotting.</p><p><b>CONCLUSION</b>Both genistein and icariin have a strong estrogen-like effect, but the estrogenic activity of genistein is stronger than icariin. It showed that the activity of icariin is stron-ger than genistein to promote ROB maturation. So it must be that icariin promotes the maturation of osteoblasts in vitro by a estogen-independent mechanism.</p>

Effect of sinusoidal electromagnetic field on bone mineral density and histomorphometry of rats at different time points / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the effect of 50 Hz 0.1 mT sinusoidal electromagnetic field at different time points on bone mineral density(BMD)and histomorphometry in rats.</p><p><b>METHODS</b>Totally 50 6-week-old female SD rats were equally randomized into 5 groups: control group,45-minute group,90-minute group,180-minute group,and 270-minute group. Except for the control group,the other four groups were given magnetic intervention in the 50-Hz 0.1-mT sinusoidal electromagnetic field for 45 minutes,90 minutes,180 minutes,or 270 minutes,respectively,on a daily basis. After 8 weeks,the total body BMD,femur BMD,and vertebral BMD were measured by dual-energy X-ray absorptiometry. The left tibia and the fifth lumbar vertebrae were separated for bone tissue static and dynamic analyses.</p><p><b>RESULTS</b>Compared with control group,the 90-minute group and the 180-minute group had significantly different total body BMD(P<0.01,P<0.05),while no such significant difference was seen in the 45-minute group and 270-minute group (P>0.05). The femur,vertebral BMD,serum biochemical markers,and the static parameters of the fifth lumbar vertebrae tissue showed significant differences in the 90-minute group,180-minute group,and 270-minute group(P<0.01),but not in the 45-minute group (P>0.05). As shown by double fluorescent labeling,the distance was sorted in an order of 90-minute group>180-minutes group>270-minute group>45-minutes group>control group.</p><p><b>CONCLUSION</b>The 50-Hz 0.1-mT sinusoidal electromagnetic field can effectively increase bone mineral density and improve bone morphology;however,the intervention effectiveness differs at different time points,with the best effectiveness seen at 90 minutes.</p>

The role of primary cilium in signal transduction and its mechanism / 浙江大学学报·医学版

The primary cilium is a solitary and special organelle that emanates from the cell surface of most mammalian cells, which is anchored to the cell by mother centriole during the interphase and G0 of cell cycle. Recent studies have revealed that the primary cilium is a sensory organelle to receive extracellular signals and plays a key role in the signal transduction and pathogenesis of diseases. This review presents the structure and the forming process of the primary cilium during cell cycle. The signal transductions associated with primary cilium, including platelet-derived growth factor receptor αα, hedgehog, Wnt are discussed and the relevant researches in the future are proposed.

Comparative study on effect of osthole and genistein on peak bone mass in rats / 中国骨伤

<p><b>OBJECTIVE</b>To compare the ability of osthole (OST) and genistein (GEN) in enhancing bone peak bone mass of rats to prevent osteoporosis.</p><p><b>METHODS</b>Thirty-six female one-month-old SD rats of (125 +/- 3) g body weight were randomly divided into three groups, 12 rats in each group, one group was orally administered osthole at 9 mg x kg(-1) d(-1), one group was given genistein at 10 mg x kg(-1) d(-1) and another was given equal quantity of distilled water as the control. The body weight was monitored weekly and the bone mineral density (BMD) of total body was measured every month. All rats were sacrificed after three months, the femoral bone mineral density, the serum levels of osteocalcin (OC) and anti-tartaric acid phosphatase 5b (TRACP 5b) were measured by Elisa. The bone microarchitectures were analyzed with micro-CT and the bone biomechanics properties were tested with universal material machine.</p><p><b>RESULTS</b>No significant differences were observed between O-treated or GEN group and the control for the food-intake and body weight during three months. However, the rats treated with OST had significant higher BMD for both total body and femur than the control and GEN group. The O-treated rats also had higher level of serum OC and lower level of TRACP 5b. Besides, they owned bigger bone volume/tissue volume, trabecular thickness, trabecular number but smaller trabecular spacing. In the three point bending tests of femurs,they were found to have larger maximum load, the young's modulus and structural model index (SMI).</p><p><b>CONCLUSION</b>Orally administered osthole could efficiently increase the peak bone mass of rats,which provide new ideas for preventing osteoporosis.</p>

Effect of different-intensity SEMFs on bone mineral density and histomorphometry in SD rats / 中国骨伤

<p><b>OBJECTIVE</b>To investigate the effects of different-intensity sinusoidal electromagnetic fields (SEMFs) on bone mineral density (BMD) and histomorphometry in SD rats.</p><p><b>METHODS</b>Thirty female SD rats were randomly divided into three groups: group A (a control group), group B (0.1 mT group) and group C (0.6 mT group). The rats in group B and C were exposed to 50 Hz SEMFs 3 hours each day. However,the magnetic intensity was different between group B and group C:0.1 mT for group B and 0.6 mT for group C. After 8 weeks, all the animals were killed. Changes of BMD and histomorphometric properties were observed.</p><p><b>RESULTS</b>Compared with group A, the BMD of whole body, femur and vertebrae of rats in group B increased significantly; the area percentage, number and width of bone trabeculae in vertebrae and femur of rats in group B were larger than those of group A; but the resolution of bone trabeculae of rats in group B was lower than that of group A. The trabecular number in group C rats were significantly decreased, compared with that in group A rats. The outcome of double fluorescence labeling in group B was found to be significantly different with that in group A. But the difference between rats in group A and C was not significant.</p><p><b>CONCLUSION</b>This study demonstrates that 50 Hz 0.1 mT SEMFs can increase BMD, improve bone tissue microstructure and, promote bone formation.</p>

Comparison between icariin and genistein in osteogenic activity of marrow stromal cells / 中国中药杂志

<p><b>OBJECTIVE</b>To compare the effect of icariin and genistein in the osteogenic differentiation of rat bone marrow stromal cells (rBMSC).</p><p><b>METHOD</b>Rat marrow stromal cells were seperated in vitro, and the optimal concentration of genisten and icriin were screened. Genistein and icariin with the concentration of 1 x 10(-5) mol x L(-1) were adopted to intereven rBMSCs cultured in vitro. Alkaline phosphatase (ALP) was determined at 3, 6, 9, 12,15 d after intervention; calcified nodule was detected with alizarin red staining at 12 d; OXS, Runx-2, bone morphogenetic protein (BMP-2) and Collagen-I mRNA expression were observed with Real-time RT-PCR at 12, 24, 48, 72, 96 h.</p><p><b>RESULT</b>Genistein and icariin with the concentration of 1 x 10(-5) mol x L(-1) could increase the activity of ALP and the content of Ca, regulate OXS, BMP-2, Runx-2 and Collagen-I mRNA expression.</p><p><b>CONCLUSION</b>Icariin showed a stronger effect in improving the osteogenic differentiation of rat bone marrow stromal cells than genistein.</p>

Mechanisms of icariin in regulating bone formation of osteoblasts and bone resorption of osteoclasts / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the molecular mechanisms of icariin (ICA) in regulating the bone formation of osteoblasts and the bone resorption of osteoclasts.</p><p><b>METHODS</b>Primary osteoblast cell cultures were obtained from newborn rat calvarial. Calcified nodules were stained by alizarin red. The mRNA levels of osterix (OSX), runt-related transcription factor 2 (Runx-2), alkaline phosphatase (ALP), Collagen1, osteoprotegerin (OPG), and receptor activator of nuclear factor-ΚB ligand (RANKL) were analyzed by quantitative real-time RT-PCR, the protein levels of OPG, RANKL, and Collagen1 were examined by Western blotting, and the intracellular Ca(2+) concentration of osteoblasts was measured on a flow cytometer using the Cellquest program.</p><p><b>RESULTS</b>Compared with control group, ICA markedly promoted bone formation by significant up-regulating the gene expressions of OSX, Runx-2,ALP, and Collagen1, the protein expression of Collagen1(all P<0.01), and the Ca(2+) concentration. Furthermore, ICA remarkably inhibited bone resorption by significant up-regulating the mRNA and protein expressions of OPG as well as the OPG/RANKL ratio.</p><p><b>CONCLUSIONS</b>ICA could promote bone formation of osteoblasts through inducting the gene expressions of OSX,Runx-2, ALP and Collagen1, and the protein expressions of Collagen1, and by increasing the Ca (2+) concentration. Moreover, ICA could inhibit bone resorption of osteoclasts through regulating OPG/RANKL signal pathway.</p>

Effects of icariin and genistein on peak bone mass in rats / 中国医学科学院学报

<p><b>OBJECTIVE</b>To compare the effects of icariin (ICA) and genistein (GEN) on rats bone peak mass and thus screen for a drug that can more effectively prevent osteoporosis.</p><p><b>METHODS</b>Totally 36 one-month SD rats were randomly divided into three groups: ICA group [25 mg/(kg·d), intragastric administration], GEN group [10 mg/(kg·d), intragastric administration], and control group (fed with equal volume of distilled water). The body weight was monitored weekly and the bone mineral density of total body was measured monthly. All rats were sacrificed three months later. The femoral bone mineral density and the serum levels of osteocalcin and anti-tartaric acid phosphatase 5b, N-terminal propeptide of type 1 procollagen, and C-terminal propeptide of type 1collagen were measured. The bone microarchitectures were analyzed with micro-CT and the bone biomechanics properties were tested with universal material machine.</p><p><b>RESULTS</b>The body weight and organ index showed no significant difference among these three groups(P>0.05). No obvious pathological change was found. The bone mineral density was also not significantly different in the first and second months; however, in the third months, the ICA group had significant higher bone mineral density for both total body and femur than those in the control and GEN group (P<0.05). The same trends were found for both femur bone mineral density and whole-body bone mineral density (P<0.05). The ICA group also had significantly higher serum levels of osteocalcin (P<0.05) and lower level of anti-tartaric acid phosphatase 5b(P<0.05). Besides, rats in the ICA group had significantly larger bone volume/tissue volume, trabecular thickness, and trabecular number than the control group, whereas the trabecular spacing and model coefficients were signicantly lower(all P<0.05), which, however, were not significantly different between ICA group and GEN group (P>0.05). Femoral maximum load, Youg's modulus, and yield load were significantly higher in these two groups than in the control group (P<0.05), which, again, were not significantly different between ICA group and GEN group (P>0.05).</p><p><b>CONCLUSION</b>Orally administered ICA is more efficient than GEN in inhibiting resorption and promoting bone formation, and thus can dramatically improve the peak bone mineral density and bone quality.</p>

Effect of osthole on bone metabolism in rat femoral tissues in vitro / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the effect of osthole on bone metabolism in rat femoral tissues in vitro.</p><p><b>METHODS</b>The rat femoral tissues were isolated in vitro. The optimal concentrations of ostehole (1×10(-5) mol/L) and estradiol (1×10(-8) mol/L) (the positive control) were selected by alkaline phosphatase activity (ALP). The ALP and calcium levels were detected by commmerical regents, and the expressions of osteoprotegerin, receptor activator of nuclear factor-κB ligand, runx-related gene 2, and bone morphogenetic protein-2 mRNA were determined by real-time reverse transcription-polymerase chain reaction.</p><p><b>RESULT</b>The osthole (1×10(-5) mol/L) significantly increased the activity of ALP, calcium level as well as the expressions of osteoprotegerin, receptor activator of nuclear factor-κB ligand, runx-related gene-2 and bone morphogenetic protein-2 mRNA in rat femoral tissues in vitro.</p><p><b>CONCLUSION</b>Osthole can improve calcium level and ALP activity and regulate the bone metabolism-related genes in rat femoral tissues.</p>

Effects of static magnetic field with different exposure time on the maturation of rat osteoblasts in vitro and the expression of the estrogen receptor gene / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the effects of static magnetic fields (SMFs) with different exposure time on the maturation of rat osteoblasts in vitro and the expression of the estrogen receptor (ER) gene.</p><p><b>METHODS</b>The calvarial osteoblasts were isolated from newborn rats by enzyme digestion and randomly divided into 9 groups after one passage based on the exposure time of the SMFs[0 (control), 0.5 h, 1.0 h, 1.5 h, 2.0 h, 2.5 h, 3.0 h, 3.5 h, and 4.0 h]. The intensity was 3.9 mT in all SMFs. Those without SMFs exposure were used as the controls. The oeteoblasts were observed under the contrast phase microscope on a daily basis. After 48 h, cell proliferation was assayed by MTT method. The osteocalcin contents were measured after exposure to SMFs for 3 d, 6 d, 9 d, and 12 d. ERΑ and ERΒ mRNA expressions were measured by real-time PCR after SMFs treatment for 0 h, 24 h, 48 h, and 72 h.</p><p><b>RESULTS</b>Compared with the controls, the cell proliferation was significantly enhanced in the 2.0-h, 2.5-h, and 3.0-h groups (P<0.05). After SMFs treatment for 6 d, 9 d and 12 d, the 2.5-h group had significantly higher osteocalcin content than the control group did (P<0.05). After SMFs treatment for 0 h and 72 h, elevated ERΑ mRNA expression and reduced ERΒ mRNA expression were observed.</p><p><b>CONCLUSION</b>Exposure to SMFs, regardless of exposure time, is associated with enhanced cell proliferation, increased osteocalcin contents, and altered ERΑ and ERΒ mRNA expressions in opposite directions.</p>

Effect of genistein on rat femoral bone metabolic activity in vitro / 药学学报

This study is to investigate effects of genistein on rat femoral bone metabolic in vitro. Rat femoral tissues was isolated and randomly divided into two groups including control group and genistein (1 x 10(-5) mol x(-1)) group. Determinations of alkaline phosphatase (ALP) activity, calcium content and osteoprotegerin (OPG), type I-collagen (Collagen-I), RANKL, Runx-2 and bone morphogenetic protein (BMP-2) mRNA expression were done by real-time PCR. The results showed that 1 x 10(-5) mol x L(-1) genistein could increase the activity of ALP and contents of Ca, regulate bone metabolism activity of OPG, RANKL, BMP-2, Collagen-I and Runx-2 mRNA expression level. Genistein can significantly modulate bone metabolism related gene expression level of rat femoral tissue in vitro, and can increase calcium content and the activity of ALP.

Inhibitory effect of 8-prenylnaringenin on osteoclastogensis of bone marrow cells and bone resorption activity / 药学学报

This study is to investigate the effect of 8-prenylnaringenin (8-PNG) on osteoclastogensis of bone marrow cells and bone resorption activity of osteoclasts. Osteoclasts were separated from long bone marrow of newborn rabbits and cultured in alpha-MEM containing 10% FBS. 8-PNG was added into culture media at 1 x 10(-7), 1 x 10(-6), 1 x 10(-5) mol xL(-1), separately. 17beta-Estradiol (E2, 1 x 10(-7) mol x L(-7)) was used as positive control. T RAP staining and TRAP activity measurement were performed after 5 days, and the bone resorption pits were analyzed after 7 days. Annexin V staining for the detection of apoptotic osteoclasts was performed after 2, 4, 8, 12, 24, 36 and 48 h separately. The mRNA expression level of TRAP and cathepsin K (CTSK) was measured by real-time RT-PCR. 8-PNG significantly reduced the number of osteoclasts which was TRAP staining positive and with more than three nucleus, the area and number of bone resorption pits decreased obviously in 8-PNG-supplemented groups. The apoptosis rate peaked earlier in the 8-PNG-supplemented groups and the mRNA expression level of TRAP and CTSK decreased significantly. All these inhibitory effects were in a dose dependent manner, the highest effect was obtained by 1 x 10(-5) mol x L(-1) 8-PNG. 8-PNG inhibits bone resorption activity of osteoclasts by inducing osteoclast apoptosis and inhibiting the gene expression and enzyme activity including TRAP and CTSK, and restrains bone marrow cells to osteoclast differentiation.

Effects of static magnetic field at different times on the proliferation and differentiation of osteoblasts in vitro / 中国骨伤

<p><b>OBJECTIVE</b>To investigate the effect of exposure to static magnetic fields (SMFs) of 3.9 mT on proliferation and differentiation of osteoblasts in vitro.</p><p><b>METHODS</b>The newborn rat calvarial osteoblasts were isolated by enzyme digestion and randomly divided into 9 groups after one passage. The intensity of the SMFs was 3.9 mT. The cells were exposed in the SMFs for 0 (control group), 0.5, 1.0, 1.5, 2.0, 2.5, 3, 3.5 and 4.0 h groups respectively. They were observed under the contrast phase microscope each day. After 48 h, cell proliferation was assayed by MTT method. The alkaline phosphatase (Alkaline Phosphatase, ALP) activities and calcium content were measured after 3, 6, 9, and 12 days exposed with SMFs. The ALP positive colonies were histochemically stained after 8 days and the calcified nodules were stained by Alizarin Bordeaux after 10 days; BMP-2, Runx-2 and Opg mRNA expression were measured after SMFs treatment in 0, 24, 48 and 72 h.</p><p><b>RESULTS</b>Contrast with control group, all SMFs groups enhanced cell proliferation (P < 0.01 or P < 0.05), and they promoted maturation and mineralization of the osteoblasts. The results showed that SMFs improved the ALP activity, promoted calcium content, boost BMP-2, Runx -2 and Opg mRNA expression.</p><p><b>CONCLUSION</b>The cells exposed to the SMFs of 3.9 mT at 2.5 h apparently promote proliferation and differentiation of osteoblasts in vitro.</p>

Effect of 3.6-mT sinusoidal electromagnetic fields on proliferation and differentiation of osteoblasts in vitro / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigated the effect of 50-Hz 3.6-mT sinusoidal electromagnetic fields (SEMFs) on the proliferation and differentiation of osteoblasts in vitro.</p><p><b>METHODS</b>The newborn rat calvarial osteoblasts were isolated by enzyme digestion and randomly divided into 6 groups after one passage. The treatment groups under 50-Hz 3.6-mT SEMFs and controls without SEMFs treatment. The cells were exposed in the SEMFs for 0.5 h, 1.0 h, 1.5 h, 2.0 h, and 2.5 h. They were observed under the contrast phase microscope each day. The calcified nodules were stained by alizarin red. The SEMFs were arranged in spiral appearance after 3 to 5 days.</p><p><b>RESULTS</b>The SEMFs showed characteristic distribution 3 to 5 days after SEMFs treatment. On the 9(th) day after treatment, the activity of alkaline phosphatase (ALP) significantly increased in the 0.5-h group, whereas the ALP histochemical straining results and the area of calcified nodules were consistent with ALP activity. In the 48-h and 96-h groups, the genetic expression levels of osteoprotegerin and collagen-1 were significantly higher than that in the control group; particularly, the mRNA expression increased in the 0.5-h group.</p><p><b>CONCLUSION</b>The SEMFs at 50-Hz 3.6-mT could suppress the proliferation of osteoblasts maturation but stimulate the differentiation and maturation of osteoblasts in vitro.</p>

Clinical analysis on causes of dental implant failure: report of 32 cases / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To analyze the causes associated with the failure of dental implant restoration.</p><p><b>METHODS</b>The patients who received dental implant restoration from January 2001 to December 2008 in Center of Dental Implant, School of Stomatology, Shandong University were reviewed and analyzed. The cases with implant loosening, broken or removed were considered failure.</p><p><b>RESULTS</b>There were a total of 38 failure implants in 32 patients found in this group of patients. Of those, 33 implants loosened (17 cases before restoration and 16 cases after restoration), two were broken, two retention screws broken and one implant perforated on buccal side. The causes of failure included doctor-related factors in 19 cases, patient-related factors in 9 cases, implant-related factors in two cases and two uncertainties.</p><p><b>CONCLUSIONS</b>Doctor-related factor is the main cause of dental implant failure, followed by patient-related factor and implant-related factor.</p>