OBJECTIVETo explore the correlation between homozygous deletions and mutation of p16 gene and the carcinogenesis and progression of squamous cell carcinoma of buccal mucosa.

METHODSThirty buccal cancers, 10 leukoplakias and 8 buccal mucosas were involved. DNA was extracted from the tissues. PCR was used to analyses homozygous deletion of p16 gene. PCR-SSCP-DNA sequencing was performed to detect the point mutation of p16 gene. Immunohistochemical techniques were used to detect the expression of P16 protein.

RESULTSGene deletions and point mutations were not found in leukoplakia and normal buccal mucosa. Gene deletions were found in 7 samples out of 30 cases of squamous cell carcinoma of buccal mucosa (23.3%), while point mutations were found in 5 samples out of 30 cases of squamous cell carcinoma of buccal mucosa (16.7%). Sequencing analysis showed that 5 cases point mutations were missense mutations, occurred on exon 2. Three cases occurred in the same point, codon 99 (GAT --> AAT). The result of immunohistochemical stains showed that 11 out of 12 cases gene inactivation did not expressed P16 protein.

CONCLUSIONHomozygous deletion and point mutation of p16 were the main pattern of gene inactivation in squamous cell carcinoma of buccal mucosa. There was a closely correlation between p16 gene inactivation and the carcinogenesis of squamous cell carcinoma of buccal mucosa.

Carcinoma, Squamous Cell ; Cyclin-Dependent Kinase Inhibitor p16 ; Gene Deletion ; Genes, p16 ; Humans ; Mouth Mucosa ; Mutation ; Point Mutation

OBJECTIVETo investigate the ectopic osteogenesis potential of human natural bone derived material combined with human bone marrow mesenchymal stem cells (MSCs).

METHODSCell-scaffold complexes were implanted subcutaneously into the left back of the nude mice, and human natural bone derived material were implanted into the right back as control group. The mice were killed respectively on the postoperative 2 weeks, 4 weeks and 8 weeks. The macroscopic, histopathological, alkaline phosphatase (ALP) activity assay methods were performed to assess the ectopic osteogenesis potential.

RESULTSThe cartilaginous osteogenesis were observed in both deproteinated bone and decalcified bone, and the more new bone tissue formed gradually as the time went by after implantation. ALP activity become stronger followed with the time (P < 0.05), and compared with the decalcified bone, deproteinated bone displayed stronger ALP activity (P < 0.05).

CONCLUSIONThe MSCs and human natural bone derived material can be used as good seed cells and scaffold materials respectively to construct tissue-engineered bone, and as the scaffold material, deproteinated bone has better osteogenesis ability than decalcifed bone.

Animals ; Bone and Bones ; Cells, Cultured ; Humans ; Mesenchymal Stromal Cells ; Mice ; Mice, Nude ; Osteogenesis ; Tissue Engineering

OBJECTIVETo study the role of microfilament polymerization in menchanotransduction by human periodontal ligament fibroblast (hPDLFs).

METHODSIn tension-force group, hPDLFs were treated by tension-force values of 18% for 8 h, 16 h, 24 h. In tension-force and inhibitor group, the sample was treated with 5 microg/mL cytochalasin B before using tension-forece. Each sample was collected and the expression of cyclooxygenase-2 was measured by using immunohistoche staining.

RESULTSIn tension-force group, the expression of cyclooxygenase-2 enhanced with the extension of loading time. In tension-force and inhibitor group, cyclooxygenase-2 expression was depressed and had no relation with loading time.

CONCLUSIONTension-force induced cyclooxygenase-2 expression is mediated by microfilament, disruption of the microfilament polymerization will destroy mechanotransduction in hPDLFs.

Actin Cytoskeleton ; Cells, Cultured ; Cyclooxygenase 2 ; Fibroblasts ; Humans ; Mechanotransduction, Cellular ; Periodontal Ligament ; Stress, Mechanical

OBJECTIVETo obtain highly enriched osteoclasts in vitro.

METHODSThe bone marrow cells of 1-day, 12-day, 24-day and 36-day old Sprague-Dawley (SD) rats were separately cultured with the presence of 1,25-(OH)2D3 and dexamethasone, and the osteoclast-like cells were identified by Trap staining and scanning electron microscope observation and were purified by trypsin digestion. The count of Trap positive osteoclast-like cells was analyzed statistically.

RESULTSThe osteoclast-like cells of each group were Trap positive cells and could form the bone absorption lacunas in vitro. The amounts of osteoclast-like cells were different statistically between the groups (P < 0.05) except between the groups of 1-day old and 12-day old (P > 0.05). Highly enriched osteoclast-like cells were harvested by the digestion of 0.25% trypsin and 0.02% EDTA.

CONCLUSIONIt's indicated that a large amount of highly enriched osteoclast-like cells could be obtained through the culture of bone marrow cells of 10-day and 12-day old SD rats with 1,25-(OH)2D3 and dexamethasone and the digestion of trypsin/EDTA.

Animals ; Bone Marrow ; Bone Marrow Cells ; Bone and Bones ; Calcitriol ; Cells, Cultured ; Dexamethasone ; Osteoclasts ; Rats ; Rats, Sprague-Dawley ; Trypsin

OBJECTIVETo evaluate the effect of Yishenqinghuo recipe on biological characteristic of rat bone marrow stromal cells (BMSCs) and search for the function and mechanism of this recipe in treatment of periodontitis.

METHODS12- to 15-month-old SD rats were allocated into 5 groups. Group A: control group (with no periodontitis model, fed with the same dosage of saline as Group D); Group B: model group (with periodontitis model, fed with the same dosage of saline as Group D); Group C: high dosage group (with periodontitis model, fed with a high dosage of medicine); Group D: middle dosage group (with periodontitis model, fed with a middle dosage of medicine); and Group E: low dosage group (with periodontitis model, fed with a low dosage of medicine). Ten days later, serums were collected from all the five groups for in vitro cultivation of BMSCs.

RESULTSThere was displayed a similarity in effect between the serum collected from Group C1 (serum collected 0.5 h after the last gavage of Group C) and that from Group A after the last gavage, the effect being the best in terms of proliferation of BMSCs. A comparison with the other groups had revealed a striking difference (P < 0.01), with Group B having turned out to be the worst. The serum from Group C2 (serum collected 1 h after the last gavage of Group C) after the last gavage could best enhance the generation and activity of ALP, having demonstrated a significant difference (P < 0.01) in comparison with the other groups.

CONCLUSIONYishenqinghuo recipe can improve the proliferation of BMSCs and facilitate the differentiation to osteoblast.

Animals ; Cell Differentiation ; Male ; Mesenchymal Stromal Cells ; Osteoblasts ; Periodontitis ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo study role of dental follicle in tooth root development.

METHODSSixteen mandibular first molar dental germs from eight five-day postnatal Balb/c mice were divided into two groups randomly. Dental follicle of germs in one group was undetached and that of another group was removed. Subsequently, each of the germs was separately transplanted to back-muscles of adult nude mice. At seventh and fourteenth day after transplanting, the germs were collected, fixed, demineralized, dehydrated, and embedded in wax in sequence. Serial sections of 5 microm thick were made following the routine methods, stained with haematoxylin-eosin dying solution, and observed under a light microscope.

RESULTSAll implantations were located in the back-muscles with abundant capillary vasculature. Under microscope, although all tooth germs could further develop after grafting, tooth germs without dental follicle developed slowly with small size and low calcification compared to those with dental follicle. Although position of Hertwig's epithelial root sheath of all germs seemed no changing, roots of the group with dental follicle could further develop and the roots develop toward the apical direction; this tendency couldn't be seen in the germs of another group. Inflammatory cells could be seen in and out of the pulp cavity of the two groups at 7th day after grafting, while no obvious inflammatory cell was observed at 14th day after grafting.

CONCLUSIONDental follicle play an important role in tooth root development. It probably can lead tooth root to develop in normal direction.

Animals ; Dental Pulp Cavity ; Dental Sac ; Enamel Organ ; Mice ; Mice, Nude ; Molar ; Odontogenesis ; Tooth ; Tooth Germ ; Tooth Root

OBJECTIVETo compare the shaping ability of ISO standard stainless steel K files and multi-taper ProTaper nickel-titanium files in simulated resin curved root canals. METHODS Thirty simulated resin root canals were randomly divided into three groups and prepared by stainless steel K files, hand ProTaper, rotary ProTaper, respectively. The amount of material removed from inner and outer wall and canal width after canal preparation was measured, while the canal curvature before and after canal preparation and canals aberrations were recorded.

RESULTSThe stainless steel K files removed more material than hand ProTaper and rotary ProTaper at the outer side of apex and inner side of curvature (P < 0.05). The mean degree of straightening in stainless steel K files group was significantly bigger than in ProTaper group (P < 0.05). The canals prepared by ProTaper had no evident aberration.

CONCLUSIONThe shaping ability of ProTaper is better than stainless steel K files.

Dental Alloys ; Dental Instruments ; Dental Pulp Cavity ; Equipment Failure ; Humans ; Nickel ; Root Canal Preparation ; Stainless Steel ; Titanium

OBJECTIVETo explore the influence of chemosensitivity of Tca8113 cells by modified MTT assay after the animal model of Tca8113 were treated by the ultrasound hyperthermia.

METHODSThe MTT assay of the BALB/C nu/nu mice model of Tca8113 cells treated by the ultrasound hyperthermia in vivo was performed.

RESULTSThe chemosensitivity to the 9 kinds of drugs demonstrated no significant differences between the Tca8113 cells in the control group, the 39 degrees C-treated group and the groups treated from 41 degrees C to 44 degrees C. But significant differences between the 40 degrees C-treated group and the 41 degrees C or 42 degrees C-treated group existed. In the heating-time grades test, there were no significant differences in the chemosensitivity to the 9 kinds of drugs between these three pairs of group (the control group and the 15 min-treated group, the 30 min-treated and the 45 min-treated group, the 60 min-treated and the 75 min-treated group). But there were significant differences between the 30 min-treated or the 45 min-treated group and the 60 min-treated or the 75 min-treated group.

CONCLUSIONUltrasound hyperthermia performed in 42 degrees C for 30-45 min can improve the chemosensitivity of Tca8113 cells to some drugs significantly, which confirms the rationality of synchronous combination of hyperthermia and chemotherapy in the chemosensitivity point of view for the first time.

Animals ; Antineoplastic Agents ; Heating ; Hyperthermia, Induced ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Mouth Neoplasms

OBJECTIVETo study the root resorption caused by edgewise appliance combined with flat bite plate treatment.

METHODS65 patients with edgewise technique and flat bite plate treatment were chosen. All patients were taken panoramic radiograph before flat bite plate treatment, immediately after flat bite plate treatment and 6 months after flat bite plate treatment. Root resorption grade of mandibular permanent incisors were analyzed.

RESULTSThere were statistical difference in the root resorption grade of three groups (P < 0.05), but there was no statistical difference between male and female (P > 0.05).

CONCLUSIONFlat bite plate can cause root resorption of mandibular permanent incisors, but the root resorption is slight.

Aged ; Dental Occlusion ; Female ; Humans ; Incisor ; Male ; Mandible ; Root Resorption

OBJECTIVETo compare the color character of VITA shade guide and the custom shade guide with metal substrate.

METHODSColor of 9 sites of 5 series of VITA shade guides and custom shade guides with metal substrate were measured by means of PR-650 spectrophotometer.

RESULTSThe color range of VITA shade guide were that L* was 56.86-73.86, a* was-1.29-3.69, b* was 7.09-21.94, and the transparence was 3.20-7.59. The color range of the custom shade guide was that L* was 60.59-78.54, a* was -1.09-4.99, b* was 7.60-22.35, and the transparence was 0.23-10.98. L*, a* and b* of the custom shade guide with metal substrate were higher than VITA shade guide, and the transparence was differet. The color difference of homonymy shade tab between custom shade guide and VITA shade guide was larger than 1.5 NBS.

CONCLUSIONThere is color difference between VITA shade guide and custom shade guide. Metal substrate has effects on the color of cero-metal prosthesis, and color selection in clinic should be carefully considered.

Color ; Dental Prosthesis Design ; Prosthesis Coloring ; Spectrophotometry