[Effects of different exercise modes on neuromuscular junction and metabolism of skeletal muscle-related proteins in aging rats].

The present study aimed to explore the effects of different exercise modes on neuromuscular junction (NMJ) and metabolism of skeletal muscle-related proteins in aging rats. Ten from 38 male Sprague-Dawley (SD) rats (3-month-old) were randomly selected into young (Y) group, while the rest were raised to 21 months old and randomly divided into elderly control (O), endurance exercise (EN) and resistance exercise (R) groups. After 8 weeks of corresponding exercises training, the gastrocnemius muscles of rats were collected, and the expression of S100B in Schwann cells was detected by immunofluorescence staining. Western blot was used to detect the protein expression levels of agglutinate protein (Agrin), low-density lipoprotein receptor-related protein 4 (Lrp4), muscle- specific kinase protein (MuSK), downstream tyrosine kinase 7 (Dok7), phosphorylated protein kinase B (p-Akt), phosphorylated mammalian target rapamycin (p-mTOR), and phosphorylated forkhead box O1 (p-FoxO1) in rat gastrocnemius muscles. The results showed that, endurance and resistance exercises increased the wet weight ratio of gastrocnemius muscle in the aging rats. The protein expression of S100B in the R group was significantly higher than those in the O and EN groups. Proteins related to NMJ function, including Agrin, Lrp4, MuSK, and Dok7 were significantly decreased in the O group compared with those in the Y group. Resistance exercise up-regulated these four proteins in the aging rats, whereas endurance exercise could not reverse the protein expression levels of Lrp4, MuSK and Dok7. Regarding skeletal muscle-related proteins, the O group showed down-regulated p-Akt, and p-mTOR protein expression levels and up-regulated p-FoxO1 protein expression level, compared to the Y group. Resistance and endurance exercises reversed the changes in p-mTOR and p-FoxO1 protein expression in the aging rats. These findings demonstrate that both exercise modes can enhance NMJ function, increase protein synthesis and reduce the catabolism of skeletal muscle-related proteins in aging rats, with resistance exercise showing a more pronounced effect.

Metformin enhances the osteogenic activity of rat bone marrow mesenchymal stem cells by inhibiting oxidative stress induced by diabetes mellitus: an in vitro and in vivo study.

PURPOSE: The purpose of this study was to determine whether metformin (MF) could alleviate the expresssion of reactive oxygen species (ROS) and improve the osteogenic ability of bone marrow mesenchymal stem cells derived from diabetic rats (drBMSCs) in vitro, and to evaluate the effect of MF on the ectopic osteogenesis of drBMSCs in a nude mouse model in vivo. METHODS: BMSCs were extracted from normal and diabetic rats. In vitro, a cell viability assay (Cell Counting Kit-8), tests of alkaline phosphatase (ALP) activity, and western blot analysis were first used to determine the cell proliferation and osteogenic differentiation of drBMSCs that were subjected to treatment with different concentrations of MF (0, 50, 100, 200, 500 µM). The cells were then divided into 5 groups: (1) normal rat BMSCs (the BMSCs derived from normal rats group), (2) the drBMSCs group, (3) the drBMSCs + Mito-TEMPO (10 µM, ROS scavenger) group, (4) the drBMSCs + MF (200 µM) group, and (5) the drBMSCs + MF (200 µM) + H2O2 (50 µM, ROS activator) group. Intracellular ROS detection, a senescence-associated ß-galactosidase assay, ALP staining, alizarin red staining, western blotting, and immunofluorescence assays were performed to determine the effects of MF on oxidative stress and osteogenic differentiation in drBMSCs. In vivo, the effect of MF on the ectopic osteogenesis of drBMSCs was evaluated in a nude mouse model. RESULTS: MF effectively reduced ROS levels in drBMSCs. The cell proliferation, ALP activity, mineral deposition, and osteogenic-related protein expression of drBMSCs were demonstrably higher in the MF-treated group than in the non-MF-treated group. H2O2 inhibited the effects of MF. In addition, ectopic osteogenesis was significantly increased in drBMSCs treated with MF. CONCLUSIONS: MF promoted the proliferation and osteogenic differentiation of drBMSCs by inhibiting the oxidative stress induced by diabetes and enhenced the ectopic bone formation of drBMSCs in nude mice.

The extract of concentrated growth factor enhances osteogenic activity of osteoblast through PI3K/AKT pathway and promotes bone regeneration in vivo.

BACKGROUND: Concentrated growth factor (CGF) is a third-generation platelet concentrate product; the major source of growth factors in CGF is its extract; however, there are few studies on the overall effects of the extract of CGF (CGF-e). The aim of this study was to investigate the effect and mechanism of CGF-e on MC3T3-E1 cells in vitro and to explore the effect of combination of CGF-e and bone collagen (Bio-Oss Collagen, Geistlich, Switzerland) for bone formation in cranial defect model of rats in vivo. METHODS: The cell proliferation, ALP activity, mineral deposition, osteogenic-related gene, and protein expression were evaluated in vitro; the newly formed bone was evaluated by histological and immunohistochemical analysis through critical-sized cranial defect rat model in vivo. RESULTS: The cell proliferation, ALP activity, mineral deposition, osteogenic-related gene, and protein expression of CGF-e group were significantly increased compared with the control group. In addition, there was significantly more newly formed bone in the CGF-e + bone collagen group, compared to the blank control group and bone collagen only group. CONCLUSIONS: CGF-e activated the PI3K/AKT signaling pathway to enhance osteogenic differentiation and mineralization of MC3T3-E1 cells and promoted the bone formation of rat cranial defect model.

[Changes in root and alveolar bone before and after treatment by retracting the upper incisors].

OBJECTIVE: Using cone beam computed tomography (CBCT) in image measurement on the patients with maxillary protrusion, the study aims to identify the changes in root and alveolar bone before and after treatment by upper incisor retraction. METHODS: The study was conducted on 37 patients who have received orthodontic treatment from January 2014 to December 2015. The sample comprised 17 males and 20 females, with an average age of 14.5 years. The patients underwent extraction of bimaxillary premolars and given maximum anchorage to retract the upper incisors. The adducent angle, adducent amount, and the amount of elongation of the upper incisor teeth were measured by cephalograms. The patients were scanned by NewTom VGi to obtain CBCT data before and after treatment with upper incisor retraction. Using the NewTom NNT tool, we obtained the multiple planar reconstruction and then adjusted the coronal, axial, and sagittal axis. The sagittal section of the long axis of the maxillary central incisor through the incisal edge and root apex was selected to measure the changes in the root and alveolar bone before and after incisional treatment. RESULTS: Before and after retracting the upper incisors, the adducent angle of central incisor measured 12.92°±6.43°. Adducent amount of the incisors reached (5.54±2.21) mm. Incisor extension amount totaled (0.60±0.95) mm. Root absorption length was (0.81±0.46) mm. Root absorption rate was 6.80%±3.60%. Statistical differences were observed in the changes in root length before and after incisor retraction (P<0.05). After upper incisor retraction, increasing distance from the labial side alveolar ridge to the cemento-enamel junction reached (0.20±0.22) mm. After treatment, we observed that the height of the labial-side alveolar bones decreased and showed statistical difference with the height of labialside alveolar bones before treatment (P<0.05). The results show the correlation between root absorption and horizontal displacement of maxillary center incisor and the distance from the upper incisor apex to labial cortical bone. A correlation also exists between the variable quantity of the labial-side alveolar bones and adducent angle of the upper incisor, with a correlation coefficient of 0.354. The results also show significant difference (P<0.05). CONCLUSIONS: After compensatory treatment of patients with maxillary protrusion, the root length of upper incisor was absorbed remarkably. The height of the labial-side alveolar bones was reduced. A greater tooth movement or beyond the anatomical limitations and alteration limits of the alveolar bone can easily lead to root resorption. A negative correlation exists between the variable quantity of the labialside alveolar bones and adducent angle of the upper incisor.

Analysis of differential expression of tight junction proteins in cultured oral epithelial cells altered by Porphyromonas gingivalis, Porphyromonas gingivalis lipopolysaccharide, and extracellular adenosine triphosphate.

Tight junctions (TJs) are the most apical intercellular junctions of epithelial cells formed by occludin, claudins, junctional adhesion molecules (JAMs), and zonula occludens (ZO). Tight junction proteins can sense the presence of bacteria and regulate the transcription of target genes that encode effectors and regulators of the immune response. The aim of this study was to determine the impact of TJ proteins in response to Porphyromonas gingivalis (P. gingivalis), P. gingivalis lipopolysaccharide (P. gingivalis LPS), and extracellular adenosine triphosphate (ATP) in the oral epithelial cell culture model. Quantified real time-polymerase chain reaction (RT-PCR), immunoblots, and immunostaining were performed to assess the gene and protein expression in TJs. It was found that P. gingivalis infection led to transient upregulation of the genes encoding occludin, claudin-1, and claudin-4 but not JAM-A, claudin-15, or ZO-1, while P. gingivalis LPS increased claudin-1, claudin-15, and ZO-1 and decreased occludin, JAM-A, and claudin-4. Tight junction proteins showed significant upregulation in the above two groups when cells were pretreated with ATP for 3 h. The findings indicated that P. gingivalis induced the host defence responses at an early stage. P. gingivalis LPS exerted a more powerful stimulatory effect on the disruption of the epithelial barrier than P. gingivalis. ATP stimulation enhanced the reaction of TJ proteins to P. gingivalis invasion and LPS destruction of the epithelium.International Journal of Oral Science (2018) 10, e8; doi:10.1038/ijos.2017.51; published online 10 January 2018.

[Eight-year clinical results of SLA surface implant for dentition defect].

PURPOSE: To evaluate the clinical effect of titanium implants with SLA surface preparation for partial prostheses. METHODS: One hundred and ninety-one implants with SLA surface preparation were implanted in 130 patients with dentition defect who required dental repair at Yantai Stomatologic Hospital Implant Center. Successful rate of the implant, changes of soft and hard tissue around the implants as well as the stability of the superstructure were recorded and evaluated by regular clinical and X-ray examinations. Data analysis was performed using SPSS 17.0 software package. RESULTS: Twenty four patients with 31 implants were lost to follow up, one implant which loosened 1 week after operation was extracted. Four implants were found with peri-implantitis. The dropout rate, survival rate and successful rate was 18.46%, 99.38% and 96.88%, respectively. No obvious biological complications were observed in 155 successful implants during the observation period. Eight years later, the marginal bone resorption reached to (1.34±0.52) mm. After 8 years, a total of 25 implants had mechanical complications, including superstructure screw mobility, falling off of the crown, porcelain fracture of restorations, implant fracture and the prosthesis success rate was 83.87%. CONCLUSIONS: SLA surface implant can not only achieve good bone integration, but also long-time maintainanance of the soft tissue around the implant and implant superstructure at a healthy and stable state,the clinical effect is better than other dental implants.

Knockdown of SKA1 gene inhibits cell proliferation and metastasis in human adenoid cystic carcinoma.

The spindle and kinetochore-associated complex subunit 1(SKA1) is a newly discovered gene, which has been associated with mitosis and tumorigenesis. However, its role insalivary adenoid cystic carcinoma (SACC) is still unknown, and the invasive and metastatic mechanism in SACC is still unclear. To explore the molecular mechanism of SKA1 in the process of malignant proliferation and metastasis in adenoid cystic cancer (ACC) cells, we employed lentivirus-mediated short hairpin RNA to knockdown SKA1 in SACC-83 cells. The results demonstrated that the lentivirus-mediated shRNA-targeting SKA1 lead to a significant down-regulation of SKA1 expression. Knockdown of SKA1 inhibited cell proliferation, cell invasion, migration and the cell cycle arrest. Furthermore, knockdown of SKA1 reduced the Ndc80, CDK4, Cyclin D1, Cyclin E1, Cyclin B1 and matrix metalloproteinase-9 (MMP-9) protein expression, but increased the p27 protein expression. These findings indicated that SKA1 might be a promising target for cancer gene therapy in human ACC.

[Evaluation of simulated mandibular models in skill training of implantology for dental undergraduates].

PURPOSE: To explore the effects of simulated mandibular models in skill training of implantology for dental undergraduate. METHODS: Pre-clinical teaching of oral implantology was implemented on simulation models for 51 undergraduates of grade 2013. Each undergraduate inserted a dental implant and took an impression in the simulation model under the teacher＇s guidance. After the training course, the scores were evaluated both objectively and subjectively. RESULTS: An average score of 91.6 was obtained in the course of oral implantology on simulated mandibular models. All students appreciated the teaching methods. They believed that training on simulation models could improve their learning interest and arouse their learning motivation. CONCLUSIONS: Simulated mandibular models are good tools in training of oral implantology for dental undergraduates education, which is worthy of wide application.

Effect of edentulous arch restored with implant supported telescopic overdenture / 口腔疾病防治

Objective@#To study the effect of the edentulous arch with implant supported telescopic overdenture. @*Methods@#Fifteen patients with edentulous jaws underwent telescopic overdenture restoration. A total of 26 prostheses were fabricated (11 in the upper jaws, 15 in the lower jaws) with 104 placed implants. The secondary crown was fabricated by wax-lost cast method. Clinical examination and radiographs were conducted. Changes in the marginal bone level around the implants were evaluated by radiograph. The satisfaction level of complete denture and implant-supported overdenture were compared. The mean follow-up time was 32 months (range 6-60 months).@*Results@#Twenty-six prostheses showed better stability, maintenance and occlusion. There were statistical differences between complete denture and implant-supported overdenture in comfort level and chewing function. 1 mm bone lost was found in two patients after 4 years. No implant was lost during the loading time. @*Conclusion @#The preliminary clinical results of this research showed that implant supported telescopic overdentures were reliable for edentulous patients.

Effects of sevoflurane preconditioning on lung injury during one lung ventilation.

BACKGROUND: To study the lung protective effects of heme oxygenase-1 (HO-1) expression and sevoflurane preconditioning in patients with lobectomy. METHODS: 30 patients receiving lobectomy were divided into two groups: propofol intravenous anesthesia group (Pro group) and sevoflurane preconditioning group (Sev group). In Pro group, propofol was used for intravenous anesthetic. In Sev group, 1%-2% sevoflurane was used during anesthesia induction to one lung ventilation (OLV). Venous blood was taken before OLV (T1), at the end of OLV (T2) and at 30 min after lung ventilation (T3) to measure the concentration of serum malondialdehyde (MDA) in two groups. HO-1 protein and mRNA expression in resected lung tissue were measured with PT-PCR and Western blot technique. Oxygenation index was detected at 2 hours after operation. RESULTS: HO-1 protein (2.88±0.23 ng/ml) and mRNA expression in Sev group were significantly higher compared to protein (1.89±0.12 ng/ml)and mRNA expression in Pro group (P<0.05). Difference was not found in MDA concentration at T1 compared to T2 (P>0.05), however, at T3, MDA concentration was higher in Pro group than that in Sev group (P<0.05). oxygenation index in Sev group was 380±67 mmHg, which was significantly different from that in Pro group (290±56 mmHg) (P<0.05). CONCLUSION: Sevoflurane preconditioning can reduce oxidative stress injury induced by OLV and protect lung tissue by increasing HO-1 expression in lung tissue.

[Role of extracellular signal-regulated kinase in osteoblast differentiation on roughened titanium surfaces].

PURPOSE: The purpose of this study was to evaluate the effect of sand-blasted and acid-etched titanium surface on MC3T3-E1 murine pre-osteoblast cell differentiation, and investigate the pathway of regulating osteogenic differentiation of MC3T3-E1 cells on sand-blasted and acid-etched titanium surface in order to elucidate the regulatory mechanisms of surface roughness on osteoblastic differentiation. METHODS: The characteristic of PT polished titanium (PT), sand-blasted and acid-etched (SLA) titanium surface were examined by scanning electron microscopy (SEM). Real-time PCR was applied to detect the expression of osteogenic genes including Runx2, OSX, OCN and OPN of the MC3T3-E1 cells cultured on the 2 groups of substrates.ERK1/2 activities in MC3T3-T1 cells were measured by Western blot on SLA surface. The data was analyzed using SAS9.0 software package. RESULTS: The result of SEM observation showed that the PT surface was turned titanium surfaces with the mean peak to valley roughness (Ra) of 0.2 µm and the corresponding Ra value of SLA was 3.2 µm. The expression levels of Runx2, OSX, OPN and OCN were significantly higher and the cell proliferation was significantly lower on SLA surfaces than on PT surfaces (P<0.05). The expression levels of Runx2, OSX, OPN and OCN were up-regulated by the effect of SLA surface with PD98095. Compared with PT surface, ERK1/2 phosphorylation was continuously inhibited by SLA. Moreover, PT surfaces treated with PD98095 and SLA surfaces without PD98095 both demonstrated reduced ERK1/2 phosphorylation of the cells and the inhibitive effect of SLA surfaces was milder than that of PD98095. CONCLUSIONS: Surface roughness is an important factor that determines osteoblast behaviors. Surface roughness of titanium substrates seems to enhance the osteoblastic differentiation of MC3T3-E1 cells and the enhancing effect of surface roughness on cell differentiation may be mediated by suppressing the activity of ERK1/2 pathway.

Effect of umbilical cord mesenchymal stem cell in peri-implant bone defect after immediate implant: an experiment study in beagle dogs.

BACKGROUND: For the sake of reducing post extraction resorption, getting optimal positioning of the implant and shortening treatment time, immediate implant placement following tooth extraction has been proposed as a treatment option. However, the large bone defect peri-implant has a negative influence on the process of bone healing. In this study, umbilical cord mesenchymal stem cells (UCMSCs) were transplanted into the bone defect peri-implant inbeagle dogs and the effect of UCMSCs on bone regeneration in peri-implant were assessed. METHODS: The mandibular second, third and fourth premolars of 8 beagle dogs were extracted bilaterally. The defects in one side were filled with platelet-rich fibrin (PRF) and then UCMSCs were injected into the defect area, while the defects in the other side were filled with PRF only as control group. The titanium implant was placed into the distal root socket of each extracted tooth. The animals were sacrificed at week 2, 4 and 8 post operative. The bone defects adjacent to the implant which are 4 mm in height, 4 mm in the mesio-distal direction and 3.5 mm in the bucco-lingual direction were made after immediate implant. Histomorphometric analysis was performed using methylene blue-fuchsin acid staining and hematoxylin and eosin (HE) staining to evaluate bone regeneration. RESULTS: The direct bone-to-implant contact (BIC) in the experiment after 4 and 8 weeks was 56.47±1.18% and 76.23±2.08%; and in the control group was40.79±0.65% and 61.17±2.79%, respectively. The percentage of newly formed bone after 2, 4 and 8 weeks was 17.60±1.5%, 49.82±4.02% and 67.16±2.1% in experiment group; and in control group 14.30±1.25%, 37.04±2.29% and 58.83±3.36%, respectively. These results represented significant differences statistically. CONCLUSION: Intra-bone marrow injection of UCMSCs can promote new bone formation. UCMSCs can be used to as excellent seed cells to repair the large defect peri-implant after immediate implant.

Effect of umbilical cord mesenchymal stem cell in peri-implant bone defect after immediate implant: an experiment study in beagle dogs.

BACKGROUND: For the sake of reducing post extraction resorption, getting optimal positioning of the implant and shortening treatment time, immediate implant placement following tooth extraction has been proposed as a treatment option. However, the large bone defect peri-implant has a negative influence on the process of bone healing. In this study, umbilical cord mesenchymal stem cells (UCMSCs) were transplanted into the bone defect peri-implant in beagle dogs and the effect of UCMSCs on bone regeneration in peri-implant were assessed. METHODS: The mandibular second, third and fourth premolars of 8 beagle dogs were extracted bilaterally. The defects in one side were filled with platelet-rich fibrin (PRF) and then UCMSCs were injected into the defect area, while the defects in the other side were filled with PRF only as control group. The titanium implant was placed into the distal root socket of each extracted tooth. The animals were sacrificed at week 2, 4 and 8 post operation. The bone defects adjacent to the implant which are 4 mm in height, 4 mm in the mesio-distal direction and 3.5 mm in the bucco-lingual direction were made after immediate implant. Histomorphometric analysis was performed using methylene blue-fuchsin acid staining and hematoxylin and eosin (HE) staining to evaluate bone regeneration. RESULTS: The direct bone-to-implant contact (BIC) in the experiment after 4 and 8 weeks was 56.47 ± 1.18% and 76.23 ± 2.08%; and in the control group was40.79 ± 0.65% and 61.17 ± 2.79%, respectively. The percentage of newly formed bone after 2, 4 and 8 weeks was 17.60 ± 1.5%, 49.82 ± 4.02% and 67.16 ± 2.1% in experiment group; and in control group 14.30 ± 1.25%, 37.04 ± 2.29% and 58.83 ± 3.36%, respectively. These results represented significant differences statistically. CONCLUSION: Intra-bone marrow injection of UCMSCs can promote new bone formation. UCMSCs can be used to as excellent seed cells to repair the large defect peri-implant after immediate implant.

[Expression of quorum-sensing related genes during Enterococcus faecalis biofilm formation].

OBJECTIVE: To investigate the relationship between the expression of the quorum-sensing related genes during Enterococcus faecalis(Ef) biofilm formation. METHODS: Ef biofilms model was established in vitro and film formation process was observed by confocal laser scanning microscope at 6, 12, 24 and 48 hours respectively.Quantification of biofilms was achieved by staining with crystal violet.Real-time fluorescence quantitative PCR method was used to detect the expression of fsrB, gelE and sprE genes in the process of Ef biofilm formation. RESULTS: A lot of live and dead bacteria unevenly distributed in Ef biofilm. The quantity of biofilms increased with time within 24 hours and was 0 h:0.00 ± 0.00, 6 h:1.09 ± 0.13, 12 h:2.10 ± 0.79, 24 h:3.30 ± 0.13, which was significantly different among the 4 time period(P < 0.05). The quantity of biofilm at 48 h(3.51 ± 0.01) increased slightly compared with 24 h(3.30 ± 0.13) , but did not show significant difference.Quantitative real-time PCR showed that the expression of quorum-sensing related fsrB increased with time within 24 hours and was 0 h:9.98 ± 0.46, 6 h:23.45 ± 1.13, 12 h:47.30 ± 2.49, 24 h: 331.30 ± 2.18, which was significantly different among the 4 time period(P < 0.05). The expression of gelE was 0 h: 6.54 ± 0.73, 6 h: 14.26 ± 1.24, 12 h: 37.47 ± 2.35, 24 h:264.80 ± 5.10(P < 0.05). The expression of sprE was 0 h: 7.72 ± 0.74, 6 h: 21.15 ± 0.96, 12 h:49.87 ± 3.18, 24 h:441.89 ± 7.74, which was significantly different among the 4 time period(P < 0.05). CONCLUSIONS: The fsrB, gelE and sprE genes are closely related to the biofilm formation in Ef.

[Effects of platelet-rich fibrin extract on MC3T3-E1 cell].

OBJECTIVE: To evaluate the effect of platelet-rich fibrin extract (PRFe) on proliferation and differentiation and F-actin cytoskeleton of osteoblasts. METHODS: The experimental group used the α-minimum essential medium (α-MEM) containing PRFe (10% fetal bovine serum), and the control group used the α-MEM (10% fetal bovine serum). The number of the osteoblasts at 1st, 3rd, 5th d was detected by methyl thiazolyl tetrazolium (MTT) assay, and the differentiation of osteoblast at 1st, 3rd, 5th,7 th d detected by the activity of alkaline phosphatase (ALP).The alizarin red dye was used to observe the number of calcium nodus at 14th, 21st d. The F-actin cytoskeleton was evaluated by confocal laser scanning microscope(CLSM) at 3rd,6th,9th,12th h. The level of osteogenetic biomarkers osteocalcin (OCN) and core-binding factor α1(Cbfα1) at 3rd,7th d were quantified by real-time PCR. RESULTS: A significant increase of absorbance at 1st, 3rd, 5th d was showed in experimental group (0.336 ± 0.011, 0.571 ± 0.039, 0.787 ± 0.050) compared to control group (0.300 ± 0.021, 0.387 ± 0.040, 0.527 ± 0.034) (P < 0.05). The absorbance of experimental group at 1st, 3rd, 5th, 7th d (0.146 ± 0.014, 0.199 ± 0.017, 0.390 ± 0.020, 0.492 ± 0.019) was significantly higher than that of control group (0.115 ± 0.014, 0.145 ± 0.015, 0.190 ± 0.015, 0.230 ± 0.026) (P < 0.05). The integrated absorbance of the calcium nodus in experimental group at 14th, 21st d (22.119 ± 3.694, 31.528 ± 3.162) was significantly higher than in control group (8.498 ± 2.041, 15.162 ± 2.526) (P < 0.05). The Cbfα1 and OCN gene expression in experimental group was higher than in control group (P < 0.05). CONCLUSIONS: PRFe could enhance the proliferation and differentiation of osteoblasts and promote the spread of F-actin cytoskeleton.

[The activity of osteoclast in peri-implant tissues in Beagle dogs].

PURPOSE: To observe the quantity and activity of osteoclast in peri-implant tissues dynamically. METHODS: An animal model of dental implants was established in 6 male Beagle dogs of 1-2 years old. Bone remodeling was tested at 3-, 7-,15-,30-,60- and 90-day after placement of implants. The mandibular bones were taken out and the morphological changes were observed under X-ray examination.Bone tissue samples underwent HE staining. The data were analyzed with SPSS13.0 software package. RESULTS: The most prominent period of osteoclasts occurred at 7-day after placement of implants. After 7 days of implantation, the activity of osteoclast gradually decreased. CONCLUSIONS: The active stage for bone remodelling in peri-implant tissues during unloading period is about 7 days after implantation.

[Expression of receptor activator of NF-κB ligand and osteoprotegerin in peri-implant tissues during unloading period].

OBJECTIVE: To observe the expression of receptor activator of NF-κB ligand (RANKL) and its decoy receptor osteoprotegerin (OPG) during unloading period of dental implants. METHODS: An animal model of dental implants was established in Beagle dogs. Bone remodeling was tested at 3, 7, 15, 30, 60 and 90 days after the placement of implants. RANKL and OPG mRNA expression were quantified by real-time PCR. Then mandibular bones were resected and some sections were observed. RESULTS: The most prominent period of bone remodeling occurred at 7 day after the placement of implants (OPG/RANKL mRNA, 2.15 ± 0.1). The expression of RANKL and OPG increased in a time-dependent manner in both soft and hard tissue. After 7 days they gradually decreased. CONCLUSIONS: Both OPG and RANKL were expressed in peri-implant tissues, and the changing tendency of RANKL and OPGmRNA was consistent with the change of bone remodeling. The active stage for bone remodelling in peri-implant tissues during unloading period is about 7 days after implantation.

[The application of guided bone regeneration technique in the restoration of maxillary lateral incisor with bone defect].

PURPOSE: To evaluate the clinical effectiveness and the satisfaction on aesthetic effectiveness of application of guided bone regeneration (GBR) technique in maxillary lateral incisor implant site. METHODS: Ninety patients were selected who only lost maxillary lateral incisor and placed with 101 implants(the implant systems were 3i, Osstem, ITI, Ankylos, BLB). The final restorations were porcelain-fused-to-metal crowns. Clinical and X-ray examinations were conducted and esthetic results were observed at 3, 6,12 months after dental implant prosthetics. RESULTS: The follow-up time was 12 months, all patients achieved successful implantation and good osseointegration around the implant. The esthetic results were perfect .Among the 90 cases, 90.7%, 92.8% and 95.5% of the patients were satisfied with the final outcomes 3,6,12 months after prosthetics. CONCLUSIONS: Good clinical effectiveness and satisfaction on aesthetic effectiveness can be obtained with GBR technique applied in maxillary lateral incisor implant site. Appropriate use of GBR technique is the solution of bone defect of maxillary lateral incisor implant site.

Effect of simvastatin on the osteogenetic behavior of alveolar osteoblasts and periodontal ligament cells.

Statins are routinely used in the clinic as cholesterol lowering drugs, but recently they were reported to also have anabolic effects on bone tissue. Since regeneration of alveolar bone is one of the primary aims of periodontal treatment, in the present study we investigated the effects of simvastatin, a lipophilic statin, on primary alveolar osteoblasts (AOBs) and periodontal ligament cells (PDLs) in vitro. The effect of simvastatin (1-100 nM) on the cells proliferation/viability after 24, 48, and 72 h stimulation was measured using 3,4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT)-assay. The alkaline phosphatase (ALP) activity was measured after stimulation with simvastatin using specific colorimetric assay. Finally, the mRNA expression levels of osteocalcin (OC), receptor activator of NF-κB ligand (RANKL), and osteoprotegerin (OPG) were measured by real-time PCR. The proliferation/viability of AOBs was significantly decreased by all simvastatin concentrations after 72 h stimulation. The proliferation/viability of PDLs was not influenced by simvastatin. ALP activity of AOBs and PDLs was increased by 1 and 100 nM simvastatin, respectively. Simvastatin induced a dose-dependent increase in OC mRNA expression of AOBs and did not influence that in PDLs. RANKL expression of AOBs was increased at all tested simvastatin concentrations and that in PDLs was increased by higher simvastatin concentrations (10-100 nM). Finally, the expression of OPG in AOBs and PDLs was stimulated by 1-10 and 100 nM simvastatin, respectively. Simvastatin seems to slightly increase the expression of osteogenic markers in AOBs and PDLs, indicating its ability to influence alveolar bone formation and periodontal regeneration.

[Clinical study of osteotome sinus floor elevation without grafting and with simultaneous implants placement].

OBJECTIVE: To investigate the clinical results of osteotome sinus floor elevation (OSFE) without grafting combined with simultaneous implant placement. METHODS: A total of 65 patients underwent maxillary sinus floor elevation from alveolus without any bone grafting from January 2000 to December 2008 and 96 implants were placed in the maxillary posterior edentulous region simultaneously. Clinical and radiography examinations were performed. The residual bone height ranged from 5 to 8 mm and the mean bone height was (6.78 ± 1.04) mm. The mean following period was 33.4 months. Statistical analysis was performed by chi square test. RESULTS: Ninety-five of 96 implants were clinically stable and functioned without any pain and other complaints. One implant was extracted 15 days after operation because of mobility and the other implants obtained osseointegration. The mean implant protrusion length was 2.6 mm, ranging from 1 to 5 mm. Different degree of new bone formation was observed in 51 (54%) of implants. New maxillary sinus floor outline was observed in 33 (35%) of implants and there was no obvious new bone in 11 (12%) of implants. There was no significant deference between the implant protrusion length and sinus floor remodeling. CONCLUSIONS: Under strict indications, the clinical results of OSFE without bone grafting combined with simultaneous implant placement were predictable in short term. The new sinus floor formation was not related to the implant protrusion length.