[Effect of BMP-2 on osteogenesis of bone mesenchymal stem cells in rats].

PURPOSE: To determine the effect of bone morphogenetic protein-2(BMP-2) on osteogenesis of bone mesenchymal stem cells(BMSCs) in rats. METHODS: The primary culture of rat BMSCs was succeeded and then was identified. The rat BMSCs were infected with the recombinant lentivirus with BMP-2(Lenti-BMP-2). The osteogenic effect of BMP-2 was observed. In addition, adhesive ability of BMP-2-BMSCs was detected through adhesion assay and expression of osteogenic factors OPN,OCN,Col-I and smad was observed by RT-PCR and Western blot. SPSS11.0 software package was used for analysis. RESULTS: Rat BMSCs were cultured and identified successfully. The osteogenic effect of BMSCs was improved by BMP-2. Lenti-BMP-2 BMSCs adhesive potential enhanced and osteogenic factors were up-regulated. CONCLUSIONS: BMP-2 may facilitate the osteogenic effect of the rat BMSCs and would provide favourable cell resource for tissue engineering.

[Role of transcription factor special AT-rich binding protein 2 in the osteoblasts differentiation of bone marrow stromal cells].

OBJECTIVE: To investigate the role of transcription factor special AT-rich binding protein 2 (SATB2) in the osteoblasts differentiation of bone marrow stromal cells (BMSC) in vitro. METHODS: Rats bone marrow stromal cells were isolated by Percoll sedimentation and the cells were placed and allowed to attach for three times. After passages, expression plasmid pBABE-hygro-satb2 was constructed, then transfected into BMSC. BMSCs were inoculated in conditioned medium and osteogenic factors were detected by western blotting and reverse transcription polymerase chain reaction (RT-PCR). RESULTS: The morphological observation of BMSC showed either spindle or polygonal pattern. The cellular phenotypic marker of the third passage was CD29 positive and CD34 negative. The growth curve possessed "S" pattern. The intensity of calfilication in BMSC was higher in SATB2 transfection group (IA value 125974 ± 241) than that in the control groups (IA value 178486 ± 406). Moreover, cell migration rate increased in SATB2 transfection group [width of scratch (0.72 ± 0.01) mm] compared with control group [width of scratch (0.83 ± 0.03) mm]. In addition, the mRNA expression of osteogenic factors runt-related transcription factor 2, Osterix, activating transcription factor 4, integrin-binding sialoprotein were upregulated. CONCLUSIONS: Cells cultured with this method have general biological characteristics and osteogenic differentiation potential in vitro. SATB2 can promote osteoblasts differentiation of BMSC.

[Measurement of the height and width of residual alveolar crests in low-set maxillary sinus patients with missing upper molar].

PURPOSE: Using spiral computed tomography and Simplant software to measure the width and height of residual alveolar crest of agomphious upper molar region at different levels around bottom of low-set maxillary sinus. To evaluate the impact of sex, age, agomphious duration, and cause of tooth extraction on the width and height of residual alveolar crest. METHODS: Forty-three patients with missing uppers molar and residual alveolar bone height being 4 to 6mm showed by panoramic radiographs were scanned by spiral computed tomography. 3D model of the alveolar crest and maxillary sinus were reconstructed using the images from CT scan and Simplant software. The height and width of the residual alveolar crest of agomphious upper molar region at different levels around bottom of maxillary sinus were measured. The data was analyzed with SPSS16.0 software package for Student's t test, analysis of variance(ANOVA) and Kruskal-Wallis H test. RESULTS: (1)The mean distance between the top of residual alveolar crest and the floor of sinus was (5.26±0.58)mm. (2)The difference between the width of internal bone wall and that of external bone wall at different levels above the bottom of maxillary sinus was significant(P<0.01), except for agomphious upper second molar at 3.75mm. (3)The height of residual crest and width of sinus floor decreased remarkably with age and agomphious duration(P<0.01) while the width of sinus lateral walls didn't change so much with them(P>0.05). (4)Height of residual crest of the tooth extracted due to periodontitis was obviously lower than that of the tooth extracted due to residual root(crown) or crown fracture(P<0.01). CONCLUSIONS: The height and width of residual crest change significantly with age, agomphious duration and causes of tooth extraction. However, the width of lateral walls above sinus floor do not change so much with those factors. The internal wall of maxillary sinus floor is wider than the external wall at agomphious molar. This anatomic feature may be taken into consideration during implantation. The site and direction of implant can be adjusted equally according to the age, agomphious duration and causes of tooth extraction, so that maxillary sinus augmentation can be avoided in part of patients with low-set maxillary sinus.

[Study on the microstructure and ESR dosimetry of tetracycline-stained teeth with SEM observation and ESR measurement].

PURPOSE: To compare the microstructure and ESR dosimetry between tetracycline-stained teeth and normal teeth by means of scanning electron microscopy (SEM) and electron spin resonance (ESR) dosimeter. METHODS: Ten first or second premolars of tetracycline-stained teeth and ten normal teeth extracted for adult orthodontic persons were collected. The enamel on the surface and the dentine on the cross section of both type of teeth were observed with SEM. The ESR signal of teeth components (enamel and dentine) was evaluated by X-band ESR spectroscopy. RESULTS: Compared with normal teeth, the enamel of tetracycline-stained teeth was of porosity and the enamel prisms were irregular. The dentinal tubules and dentinal matrix also showed obvious difference between the two type of teeth. The X-band ESR spectrum of tetracycline-stained teeth was different from normal teeth. CONCLUSION: The microstructure and the native radicals have significant effect on the tetracyclines deposited in the teeth.

[Relationship of putative periodontopathogenic bacteria and drug-induced gingival overgrowth].

OBJECTIVE: To investigate the effect of putative periodontopathogenic bacteria on the development of drug-induced gingival overgrowth (GO) in renal transplant recipients. METHODS: A total of 57 patients undergoing cyclosporine treatment were divided into two groups according to GO index: with gingival overgrowth (group A) and without gingival overgrowth (group B). Demographic, pharmacologic and periodontal data were analyzed. The real-time polymerase chain reaction (PCR) method was used to detect and quantify five putative periodontopathogenic bacteria, including Porphyromonas gingivalis (Pg), Actinobacillus actinomycetemcomitans (Aa), Prevotella intermedia (Pi), Treponema denticola (Td) and Tannerella forsythia (Tf) in subgingival samples. Moreover, the relationship between the bacterial amount and the severity of GO was analyzed. RESULTS: Group A presented a significantly higher plaque index, sulcus bleeding index and probing depth than group B (P < 0.01). The occurrences of Pg, Td, and Tf in the group A (96%, 82% and 89%) were significantly increased compared with those in the group B (69%, 55% and 66%, P < 0. 05), respectively. The prevalence of Pg, Td, and Tf in the group A (79%) was markedly higher than that in the group B (38%, P < 0.01). The bacterial amount of Pg, Td, Tf and Pi were enhanced along with the severity of GO. However, the bacterial amount of Aa had no difference between two groups. CONCLUSIONS: Pg, Td, and Tf may have a significant relationship with the development of GO.

[Investigation of the prevalence of drug-induced gingival overgrowth in renal transplant recipients medicated with cyclosporine A or tacrolimus].

PURPOSE: To investigate the prevalence of gingival overgrowth(GO) in a group of renal transplant recipients medicated with cyclosporine A(CsA) in comparison to those medicated with tacrolimus(Tcr). METHODS: 107 renal transplant recipients ( 85 CsA and 25 Tcr) were recruited into this study. Demographic, pharmacologic and periodontal data was recorded. The prevalence and severity of GO were compared between the two groups. The data was analyzed by SPSS13.0 software package for independent sample t test, chi(2) test, Mann-Whitney U test and stepwise regression analysis. RESULTS: The prevalence of GO in the CsA group(49%)was significantly higher than that in the Tcr group(16%)(P<0.05). The CsA group showed a higher mean GO score (30.3+/-15.5) compared with the Tcr group(17.5+/-9.6) (P<0.001).In addition, the patients with GO presented a significantly higher plaque index and papilla bleeding index than those without GO in two groups(P<0.05). CONCLUSION: The prevalence of GO is higher in renal transplant recipients taking CsA compared to Tcr. Plaque-induced gingival inflammation has a close relation with the severity of GO.

[Application of Bränemark system's multi-unit abutment: report of 37 consecutive cases].

PURPOSE: To evaluate the short-term clinical effect and advantages of Bränemark system's multi-unit abutment used for standard or MK III implants supported fixed prosthodontics. METHODS: Routine clinical examinations and preparations, including panoramic tomography, periapical radiograph and surgical guide plate, were performed in 37 cases with multiple lost teeth. A total of 117 Bränemark system's implants were placed using a two-stage surgical approach. Multi-unit abutment connection was performed 3-6 months after implant installation. All superstructure prosthetic appliances were porcelain-fused-to-golden metal bridges. RESULTS: The follow-up period for the implants was 12 to 24 months. The total survival rate was 95.7%. Two implants were lost at second-stage surgery (the survival rate was 98.29% for first-stage), and 3 implants were lost after loading (the survival rate was 97.43% for second-stage). The other 112 implants function uneventfully. There were no bone loss around implants, no abutment and gold cylinder screw loosen. CONCLUSIONS: The multi-unit abutment, on basis of collecting all the merits of the traditional abutment, was further designed in a simplified way, which not only expands its clinical application, operate easily, but also enhance its whole superstructure. It is more suitable for implant supported fixed prosthodontics with high success rate and more advantages than the traditional abutment.

[Cloning of p53/p21 fusion gene and it's inhibitory effect on the growth in Tca8113 cells].

OBJECTIVE: To study the p53/p21 fusion gene as a potential fusion gene for the gene therapy of human oral squamous cell carcinoma. METHODS: p21 cDNA was obtained from normal human embryonic lung cells by RT-PCR, fusing with p53 gene. The recombinant plasmid pcDNA-p53/p21 was constructed by inserting the p53/p21 fusion gene into eukaryotic expression vector pcDNA3.1 and subsequently transfected into human oral squamous cell carcinoma cell line (Tca8113) with lipofectamine. RT-PCR and Western blot were used to demonstrate the expression of p53/p21 fusion gene. Using clonal formation experiment and (3)H-TdR incorporation assay were used to evaluate the clonal formation and proliferation ability of Tca8113 cells. RESULTS: It was observed that p53/p21 fusion gene could inhibit clonal formation and proliferation of human oral carcinoma. RT-PCR and Western blot demonstrated that it was the expression of exogenous p53/p21 fusion gene that led to the above results. CONCLUSIONS: Transfection of p53/p21 fusion gene to Tca8113 cells could inhibit the tumor cell proliferation and clone formation in vitro, and make itself a potential fusion gene for the gene therapy of human oral squamous cell carcinoma.