Dental bonding technique has become an essential technique for dental clinical practice over the past several decades. Dental adhesion is widely used in direct and indirect restorations. However, problems such as technique sensitivity, postoperative sensitivity, secondary caries and marginal discoloration always appear in the dental bonding procedures. Fiber post and all -ceramic restoration bonding are essential step in esthetic dentistry. If these problems are not well handled, it will result in failure of the restorations. Therefore, the aim of this article is to provide adequate consultations and advice for the clinical practitioners based on the author’s experience and relevant literatures.

Objective  To provide reliable seed cells with unlimited passage proliferation and stable biological characteristics for periodontal tissue engineering research through infecting a retrovirus carrying SV40Tag into SD rat dental follicle cells. Methods  Retroviral virus vector containing SV40Tag by 293 cells was packaged and infected into SD rat dental follicle cells. Normal dental capsule cells were used as control group. The cell morphology and vitality were observed by inverted microscope, telomerase activity, osteogenic differentiation and proliferation of dental follicle cells were analyzed. Results  The SD rat dental follicle cells infected with SV40Tag could be passaged for 60 generations in vitro culture with strong growth activity. The telomerase activity was significantly enhanced compared with the control group（P=0.033）. The expression of alkaline phosphatase, osteocalcin, bone morphogenesis protein-2, Runx2, basic fibroblast growth factor, insulin-like growth factors had no statistical difference compared with control cells（P>0.05）. Conclusion  The SD rat dental follicle cells infected with SV40Tag not only have a strong growth activity and infinite passaged capacity, but also have a stable biological roperty as normal dental follicle cells, so it can be regarded as the excellent seed cells in periodontal tissue engineering.

Objective  To investigate the expression of chemokine receptor CXCR4 and its ligand CXCL12 in oral squamous cell carcinoma（OSCC） cells, and their effects on proliferation and migration of tumor cells. Methods  The expression of CXCR4 mRNA and protein in 20 cases of OSCC tissue, cervical lymph nodes, tongue cancer cell line Tca8113, buccal cancer cell line Bca885, and 10 specimens of normal oral mucosa tissue were examined by reverse transcriptase-polymerase chain reaction（RT-PCR） and Western blot. The expression of CXCL12 mRNA was examined by RT-PCR. MTT assay was used to evaluate the CXCR4/CXCL12 influence on proliferation of tumor cells. Chemotaxis and migration response to CXCR4 particular ligand-CXCL12 were detected by chemotaxis assay. Results  1）Ex- pression levels of CXCR4 mRNA and protein in OSCC tissues, Tca8113 and Bca885 cells were 2.31±1.13, 1.89±1.20,1.67±1.10 and 1.36±0.15, 1.85±0.34, 1.97±0.23, respectively. CXCR4 mRNA and protein couldn’t be detected in normal tissues. CXCL12 mRNA level in cervical lymph nodes was 1.14±0.87, CXCL12 mRNA couldn’t be detected in OSCC and normal tissues. 2）In MTT assay, recombinant CXCL12 stimulated proliferation of tumor cells and CXCR4 neutra- lization by monoclonal antibodies decreased proliferation. 3）The chemotactic migration of OSCC cells could be induced by CXCL12. CXCL12 at a concentration between 30 ng·mL-1 and 100 ng·mL-1 induced the chemotactic migration of OSCC cells in a dose-dependent manner. Conclusion  CXCR4/CXCL12 system may promote proliferation and migration of tumor cells, and may play an important role in lymph node metastasis of OSCC.

 Objective  To observe the influence of copper -bearing stainless steel on adhesion, proliferation and apoptosis of vascular endothelial cell（VEC）. Methods  The samples of two kinds of materials were inoculated with VEC and incubated for 1, 2 and 3 d. After stained by acridine orange, the cells adhered on the surface of samples were observed under a fluorescent microscope. The proliferation of VEC was detected by methyl thiazolyl tetrazolium（MTT） test. Next, leaching liquor of these two kinds of materials was prepared and used to culture VEC. The apoptosis of VEC was measured by flow cytometry. Results Fluorescent microscope showed VEC spread into fusiform shape, copper-bearing stainless steel surfaces had a significantly higher number of adherent VEC than 316L stainless steel at 1 and 2 d（P<0.05）. No significant difference of adherent VEC was observed between two kinds of materials at 3 d（P>0.05）. MTT results indicated that the optical density（OD） value of copper-bearing stainless steel were higher than that of 316L stainless steel at 1 and 2 d（P<0.05）. No significant difference of OD value was observed between two kinds of materials at 3 d（P>0.05）. The early apoptosis ratio of 316L stainless steel was higher than copper-bearing stainless stee（l P<0.05）. Conclusion  Copper-bearing stainless steel could promote the adhesion, proliferation of VEC, and inhibit the early apoptosis ratio of VEC.

 Objective  To investigate the effect of en-masse retraction of maxillary anterior teeth by rocking-chair archwire（RCA） in sliding mechanics. Methods  The three dimensional finite element model of maxillary teeth was created based on spiral CT data of a patient by ANSYS software. The forces on each tooth and the torques on the six center of resistance（CR） of the anterior teeth induced by the deformation of RCA with different depth and anterior retraction hook（ARH） with different height were calculated when retracted from a mini-implant between the first molar and the second premolar. The movements of anterior teeth were observed combining different depth of RCA with different height of ARH. Results  The clockwise torque in sliding mechanics to realize en-masse retraction of the anterior teeth could be counterbalanced by RCA of certain depth. The combination of 7.2 mm ARH and 2 mm RCA can be used to intrude and retract maxillary anterior teeth under the condition of applying mini-implant. Conclusion  The excessive retraction that usually exists in traditional treatments can be avoided by RCA in sliding mechanics and intru- sion and torque control during anterior segment retraction can also be achieved by this method.

Objective  To investigate the changes in the number and distribution of myoepithelial cells during atro- phy of the rat parotid gland. Methods  Atrophy of the right parotid was induced by ligating the right stensen duct of rats, histological changes of parotid glands were examined by hematoxylin-eosin（HE） staining during each step of glandular atrophy at the time of 0（control）, 1, 3, 5, 7, 14, 21, 30, 60, 100, and 150 days after ligation. Immunohistochemical labelling was performed to study the changes in number and distribution of myoepithelial cells during atrophy of the rat parotid gland. Results Histological analysis showed disappearance of the acini at 5 d and gradual decrease and fibrosis of the glandular lobules accompanied by the occurrence of duct like structures. Quantitative analysis of myoepithelial cells showed significant increase in number up to day 5 after ligation, then followed by gradual increases at a low level, at last it was followed by a rapid decrease after the total number reached the peak in 100 days. In addition, the acini and intercalated ducts were covered by myoepithelial cells ranged from the shape of spindle to stellate during the early phase of atrophy, while spindle-shaped myoepithelial cells were located at the periphery of duct- like structures in the later phase of atrophy. Conclusion Myoepithelial cells proliferated rapidly up to day 5 after ligation, then followed by gradual increase at a low level, at last it was followed by a rapid decrease after the total number reached the peak in 100 days.

Objective  To observe and improve the short-term outcome of alveolar bone graft （ABG） by palate side approach. Methods  ABG by palate side approach was performed in twenty patients with non -syndromic unilateral complete cleft lip and palate. Eight patients were incomplete cleft alveolar, and twelve patients were complete cleft alveolar. Each patient took cone beam computer tomography（CBCT） before and after surgery. The related data was
measured by Image-Pro Plus 5.1 and analyz statistically. Results  The overall implanted bone mass ratio was 88%, the labially implanted bone mass ratio was 93%, and the palately implanted bone mass ratio was 84%. Conclusion  ABG solve the shortcoming of bone insufficient at palatal side. Triangle nasal flap in cranny can assume the closure of nasal floor and palatal mucosa, avoid a large range of relaxation incision and applying of buccal mucosal advancement flap.

 Objective  The objective of this study is to investigate the position change of hyoid bone in obstructive sleep apnea and hypopnea syndrome（OSAHS） induced by oral appliance（OA） of double-pull rods and analyze rele- vant factors, subsequently investigate treatment mechanism of OA for OSAHS. Methods  Nine OSAHS patients（male）, confirmed by polysomnography and excessive daytime sleepiness, were treated with OA of double-pull rods. After a 3- months treatment period, CT scan and three-dimensional reconstruction were made to each patient in central relation with and without OA respectively. The volume of upper airway and hyoid bone position were three-dimensional re- constructed and measured. Results  After treatment with OA of double-pull rods, the hyoid bone position was obviously changed in horizontal （5.90±2.27）mm and vertical position （3.31±1.82）mm, the volume of upper airway was enlarged（32.36±14.58）%. ΔH-C3hor and ΔH-C3ver were positively related to Δvolume%（r=0.77, P<0.05; r=0.79, P< 0.05）, negatively related to FH-MP（r=-0.83, P<0.05; r=-0.76, P<0.05）. Conclusion  The hyoid bone position significantly change after using OA of double-pull rods. Patients with smaller FH-MP have larger horizontal change of hyoid bone.

Objective To investigate influence of oral diseases on child oral health-related quality of life, and to identify the dimensional structure of the early childhood oral health impact scale（ECOHIS）. Methods  The Chinese language version of ECOHIS was applied to 280 patients aged 2-5 years old from the paediatric dentistry clinic of West China School of Stomatology, Sichuan University. The three-dimensional construct was confirmed by confirmatory
factor analysis（CFA）. Results  Two hundred and sixty-eight valid questionnaires（95.7%） were reclaimed. For the child impact section of the ECOHIS, “pain in the teeth, mouth or jaws” was the most frequently reported item by the parents. Item of “feeling upset or guilty” was most frequently reported in the family impact section of the ECOHIS. The CFA results indicated that all factor loadings to its items were 0.25-0.81 with one factor loadings less than 0.30. The modified factor model revealed a better fit to the data. Conclusion  Oral diseases have negative impact on the children’s oral health-related quality of life. ECOHIS is a three-dimensional structure.

 Objective To compare the effects of video or leaflet in conjunction with traditional patient education （TPE） with traditional patient education alone for the compliance and satisfaction of the patients with temporomandibular disorder（s TMD）. Methods  One hundred and thirty-three patients with TMD who needed intra-articular injection of hyaluronate were included and randomly divided into three groups: Group Ⅰ accepted video education plus TPE, Group Ⅱ accepted leaflet education plus TPE, Group Ⅲ accepted TPE alone. All the participants were recorded by demographic characteristics（sex, age） before treatment, and their compliance, satisfaction and self-exercise were also recorded after one month followed-up. Results  The baseline parameters（sex, age and diagnosis） of the groups were simila（r P>0.05）. Seventeen participants lost in follow-up, including 4.5% in Group Ⅰ, 11.1% in Group Ⅱ and 22.7% in Group Ⅲ. There were significant differences in lost rates among the three groups（P=0.035）. The rates of participants who exactly followed the appointed follow -up were higher in Group Ⅰ and Ⅱ than in group Ⅲ（P =0.04）. And the satisfaction rates were 90.5% in Group Ⅰ, 92.5% in Group Ⅱ, 76.5% in Group Ⅲ. The satisfaction rates of Group Ⅰ and Group Ⅱ were significantly higher than that of Group Ⅲ（P=0.05）. The patients in Group Ⅰ and Group Ⅱ were more compliant with the self-exercise than that in Group Ⅲ（P=0.007）. Conclusion  Adding video or leaflet education to the TPE could increase the patients’compliance, satisfaction and execution of the self-exercise.

 Objective  To evaluate the survival rate and complications of endodontically treated residual crowns and roots restored directly or by glass fiber post and core or cast metal post and core. Methods  In this study, 96 patients with a total of 142 teeth were selected. All the teeth were undergone root canal therapy. And then, according to different situations, some of them were restored with glass fiber post and core, another with cast metal post and core, the rest were restored directly in the strict controlled indications. Results  The teeth（135） in 89 patients were divided into three groups. The first group contained 73（54.1%） teeth restored with glass fiber post and composite resin core. The survival rate reached 97.3% in the average observation period of （5.7±1.9） years. The second group contained 40 teeth, restored with pure titanium casting post and core. The survival rate reached 87.5% in the average observation period of （6.2±2.2） years. The last group contained 22 teeth received no treatment. The survival rate reached 90.9% in the average observation period of （5.4±1.8） years. The success rate had no significant difference among the three groups. The most common complications after restored included root fracture（6.7%）, retention loss（2.2%）, secondary caries（1.5%） and periapical periodontitis（0.7%）. Conclusion  Under the premise of high quality root canal treatment and standard restoration treatment, the abutment teeth, whether are restored by glass fiber post and core, cast metal post and core or without post, have a higher survival rate over 5 years of observation period and complications especially root fracture still should attract the necessary attention.

 Objective To analyze caries activity of nasopharyngeal carcinoma（NPC） patients before and after radiation therapy. The study was also designed to analyze calcium and phosphorus concentrations in saliva of NPC patients before and after radiotherapy. Methods  Twenty-eight NPC patients and 20 healthy controls were included in this study. Resazurin disc method was used to detect caries activity of NPC patients before and after 70 Gy radiotherapy. The atomic absorption spectrometry and molybdenum-stibium antispetrophotography method were used to analyze calcium and phosphorus concentrations in saliva of NPC patients before and after 70 Gy radiotherapy and the healthy controls. Results  The results of resazurin disc method showed caries activity of NPC patients was increased after radiotherapy（P<0.01）. Calcium concentration in saliva of NPC patients before radiotherapy was （63.19±3.27）mg·L-1,
phosphorus concentration was （132.96 ±5.13）mg·L -1. After 70 Gy radiotherapy, calcium concentration was （33.38 ± 0.32）mg·L-1, phosphorus concentration was （49.18±2.66）mg·L-1. The difference of calcium and phosphorus concentrations in saliva before and after radiotherapy was significan（t P<0.01）. Conclusion  Caries activities of NPC patients increase after radiotherapy. Calcium and phosphorus concentrations in saliva decrease after radiation therapy.

Objective To evaluate the influence of different surface treatments on porcelain surface topography. Methods  Metal ceramic prostheses in 6 groups were treated according to the different surface treatment methods, and the surface topography was observed through scanning electron microscope（SEM）. Group A was the control one （untreated）, group B was etched by 9.6％ hydrofluoric acid（HF）, group C was deglazed by grinding and then etched by 9.6% HF, group D was treated with Nd: YAG laser irradiation（0.75 W） and HF etching, group E was treated with Nd: YAG laser irradiation（1.05 W） and HF etching, and group F was treated with laser irradiation（1.45 W） and HF etching. Results  Surface topography was different in different groups. A lot of inerratic cracks with the shapes of rhombuses and grid, and crater with a shape of circle were observed on the ceramic surface after treatment with energy
parameters of 1.05 W Nd: YAG laser irradiation and 9.6% HF etching（group E）. Surface topography showed a lot of concaves on the inner wall of the cracks, and the concaves with diameter of 1-5 μm could be observed on the inner wall of the holes, which had a diameter of 20 μm under SEM. Conclusion The use of Nd: YAG laser irradiation with the energy parameters of 1.05 W and the HF with a concentration of 9.6% can evenly coarsen the porcelain surface, that is an effective surface treatment method.

Objective To explore the suitable level and action time of 17-β estradiol and fluid shear stress（FSS） and their combined effect on the proliferation of rat osteoblasts in vitro. Methods  MC3T3-E1 osteoblasts were adopted after subcultured and different concentrations of 17-β estradiol and FSS values were applied respectively on MC3T3- E1, the suitable level of 17-β estradiol and FSS were selected through MTT and alkaline phosphatase（ALP）. Then the two factors at the suitable level were applied simultaneously to MC3T3 -E1 to detect the proliferation activity. Results  Seventeen-β estradiol
（10-8 mol·L-1） for 5 d and 12×10-5 N FSS for 60 min exhibited better effects on the proliferation activity than the other groups respectively, and the combined effect of both factors was better than any single-factor treated group. Conclusion Both 17-β estradiol and FSS have a suitable threshold in promoting proliferation of osteoblasts, and two-factor treated group exhibits better effect than any other single -factor treated groups. Therefore 17-β estradiol and FSS have a synergetic action on differentiation and proliferation of osteoblasts.

Objective  To investigate the effect of Eucommiol on osteogenic differentiation of adipose-derived stem cells（ADSCs）, and the feasibility of applying in mandibular defects repair using ADSCs combined with the extract of Eucommiol scaffold material. Methods  Forty-eight New Zealand rabbits were randomly divided into four groups and bilateral mandibular defect was prepared. Group A: Implanted the ADSCs combined with the extract of Eucommiol scaffold, group B: Implanted the ADSCs combined with hydroxyapatite materials, group C: Implanted hydroxyapatite materials, group D: The control group. All the experimental animals were sacrificed after 2, 4, 8, 12 weeks. Tissue samples were observed by gross observation, radiographic analysis, hematoxylin-eosin（HE） staining, scanning electron microscope（SEM）. The value of imaging analysis and  osteogenesis were evaluated. The results were analyzed by SPSS 17.0 statistical software. Results  In vivo imaging and histological staining showed that the healing of bone defect and bone quality in group A was significantly better than those in the other groups. SEM showed well biocompatibility between composite material and tissue without inflammation reaction. By measuring and analyzing the dental CT data and new bone area, the bone in group A was obviously better than those in other groups（P<0.05）. Conclusion  The extract of Eucommiol can promote ADSCs into bone cells. The role of ADSCs combined with extract of Eucommiol scaffold materials has significant bone induction. It is expected that this material could become a new composite material and be used to fix the jaw bone defects.

Objective  To compare shear bond strength（SBS） between composite resin core（CRC） disposed with three different surface treatments and glass ionomer cement（GIC）, so that to provide theoretical basis for luting of crowns to CRC. Methods  According to three different surface treatments, thirty blocks of CRC were randomly and equally divided into three groups: Roughening with diamond grit bur（RDB）, RDB plus etching with GlumaR Etch 35 Gel （RDBE）, RDB plus coating with AdperTM Single Bond2 adhensive（RDBA）. All CRC were cemented with GIC. All specimens were preserved in 37 ℃ water for 24 h, then SBS tests for eight specimens in each group were performed using a universal testing machine at a constant crosshead speed of 0.5 mm·min-1. The surface topography of one CRC of each group was observed using field emission scanning electron microscope（FE-SEM） at 100 amplification. The interface between CRC and GIC was observed using FE-SEM at 500 amplification. Then the nature of failure was also recorded using FE-SEM at 25 amplification and the data were analyzed with a Kruskal-Wallis H test. Results  The surface topography of each group and the interface  between CRC and GIC observed using FE-SEM were significantly different, but significant differences on the nature of failure between groups were not found（P>0.10）. SBS of each group was （4.28±0.18）MPa for RDB, （4.65±0.17）MPa for RDBE, （2.39±0.21）MPa for RDBA, respectively（P<0.01）.
Conclusion  The SBS between CRC and GIC is affected by the surface treatments of CRC.

Objective  To reconstruct a three-dimensional nonlinear finite element model of mandibular teeth with three-pieces segment arch, and analyze the mechanical properties of intrusive arch and the biomechanical characteristics of three-pieces segment arch. Methods  Three-dimensional nonlinear finite element model of mandible with three-pieces segment arch was reconstructed by multi-slice spiral CT scanning, Mimics, CATIA and Anasys software. Then, the mechanical properties of intrusive arch, the movement trend and stress distribution of three-pieces segment arch were calculated by Anasys software. Results  In the range of 5°-25°, with the degree of intrusive arch increased, the force of intrusive arch also increased rapidly. The maximal force was 0.604 8 N in 30°; the force was about 0.59 N in 30°-65° range. In condition of three-pieces segment arch mechanics, lateral incisor tipped labially and intruded; the first moral tipped distally and rotating; other teeth did not move clearly. The largest stress distribution in the whole arch was in the one-third labial cervical area of the lateral incisor root and the root bifurcations of first moral. Conclusion  Under an appropriate intrusive force, three-pieces segment arch can intrude incisors and control the extrusion of posterior teeth. It can be used to correct the deep overbite, especially with high mandibular planes, gummy smile or adult patients.

Objective  To identify Streptococcus mutans（S. mutans） strains from clinical samples. Methods  Plaque samples from caries-active and caries-free sites on enamel surfaces were obtained and cultivated for S. mutans isolation. Morphology, biochemistry, automatic microorganism analysis system and polymerase chain reaction using primers homo- logous to surface protein antigen Ⅰ/Ⅱ（spaP）, glucosyltransferase B（gtfB） and dextranase（dexA） were used to identify S. mutans. Genotype of isolated S. mutans was determined by arbitrarily primed polymerase chain reaction. Results  Forty-six strains of S. mutans were obtained from the 32 subjects and were identified as S. mutans by biochemistry, automatic microorganism analysis system and polymerase chain reaction. Five identical genotypes were found by arbitrarily primed polymerase chain reaction. Conclusion  Forty -one strains of S. mutans with different genotype were obtained from clinical samples.

Objective  To establish subseries cell lines from single cancer cell of Tca8113M1 cell line and detect the cancer stem cell markers in the different subseries cell lines. Methods  The subseries cell lines from single cancer cell of Tca8113M1 cell line were established by limiting dilution assay in vitro. The  characteristic of tumorigenicity and CD44, CD184, extracellular soluble antigen（ESA） of the cancer stem cell markers were detected by xenotransplantation and flow cytometry respectively. Results  Total 192 single cells of Tca8113M1 cell line were cultured and were deposited as one cell per well. There were 12 subpopulations origin from 192 single cells spheroid cultures. The ratio was 6.25%（12/192）. In the different subpopulations, the tumorigenicity and expression of CD44 and ESA were at high levels, but the expression of CD184 was in different level. There were three kinds morphology of colonies derived from single cancer cells, holoclone, meroclone and paraclone. Cell line could be derived from carcinoma cell holoclones by cell culture. Meroclone and paraclone did not exist in cell culture in vitro. Conclusion  Tongue cancer stem cell may exist in Tca8113M1 cell line, cell line can be established and holoclone is the origin of cell line. This is a novel approach to the identification and enrichment for cancer stem cell.

Objective  Take human oral squamous cell carcinoma Tca8113 as experimental model, and study the anti oral squamous cell carcinoma activity of high mobility group chromosomal protein N2（HMGN2） molecule. Methods  Train a large number of recombinant human HMGN2 expression vector Escherichia coli BL21. HMGN2 was expressed under isopropyl-1-thio-β-galactopyranoside（IPTG） induction and purified by B-PER GST Fusion Protein Purification Kit. A variety of concentrations HMGN2 were added to cell culture medium, cells were tested by MTT, Hoechst 33342 fluorescence staining, flow cytometry assay and Western-blot. Results  MTT results proved that HMGN2 could significantly inhibit human oral squamous cell carcinoma Tca8113 growth. Hoechst 33342 fluorescence staining, flow cytometry assay test and Western-blot proved HMGN2 could make Tca8113 cells morphological change, make Tca8113 cells block in S period of cell cycle and strongly promote Tca8113 cells to apoptosis. Conclusion  HMGN2 can promote apoptosis of oral squamous cell carcinoma cells.

Castleman’s disease（CD） is an uncommon special lymphoproliferative disorder. Four cases of CD in head and neck were reported, which clinical presentations were localized type, histopathological presentation were belong to hyaline vascular variant. The prognosis was good after surgical resection. The clinical symptom, cause, pathology, diagnosis, and trearment of CD were overviewed.

Prosthodontic treatment for patient with hypohidrotic ectodermal dysplasia（HED） is difficult to manage because of the loss of occlusal vertical dimension, abnormal alveolar ridge and anodontia. A 20-year-old case with HED was reported. The patient was treated with occlusal reconstruction by a maxillary fixed prosthesis and mandibular telescopic prosthesis. At one-year’s follow-up, dentures were well used and occlusal function of the patient returned to normal.

Two cases of cleidocranial dysplasia（CCD） were reported and the characteristics of CCD were analyzed. The propositus verification method was used to family members for general health and oral specialized examination. All patients expressed developmental abnormality of crania, teeth and clavicle.

The competency oriented management theory and method, which was proved to be an effective management measure, have been put into practice in many areas including high education. This essay will probe into the possibility of introducing the competency oriented management theory into the education of undergraduate stomatology students, analyze and research its feasibility from a theoretical point of view by combing the features of stomatology students and the patterns of educating stomatology students. This essay proposes a new pattern of training elite students of stomatology major with competency as the orientation and summarizes the practical experiences in training such elite students.

The human resident microorganisms constitute the second genome of human body. Oral microbiome is closely related to the oral and systemic health and diseases. Implementation of high-throughput gene chip and second- generation sequencing has gained in-depth characterization of the oral microbiome, changing our view on host-microbe interactions. In this review, we summarized the latest progress in oral microbial metagenomics and addressed its potential value in the prevention and treatment of oral diseases and other systemic disorders.