Successful endodontic treatment depends on the effectiveness of the cleaning and shaping of the root canal system. Due to the complexity of the structure of root canal system and the particularity of root canal infections, the equipment and technology currently available for root canal preparation hinder the ability to adequately clean and shape the root canal system. In this review, we summarized the difficulties in the control of root canal infection, the new concept of three-dimensional root canal preparation, and its quality control and assessment.

Objective  To analyze the effects of nicotine on the bone calcium and phosphorus content and alkaline phosphatase(ALP) activity in rat alveolar bone and mandible. Methods  Twenty health male Wistar rats of five weeks of age were randomly assigned to two groups and received daily intraperitoneal injections for three months as follows: Saline solution for control group, nicotine 0.73 mg·kg-1·d-1 for experimental group. The bone calcium phosphorus content were detected by concentrated acid digestion method and the ALP activity was examined by improved Reddi method. Results  Compared to the control group, bone calcium and phosphorus content was lower in the experimental group(P<0.05), ALP activity had no statistical significance(P>0.05). Bone calcium phosphorus and ALP activity in different parts had no statistical significance(P>0.05). Conclusion  The nicotine reduces calcium phosphorus deposition of jaw bone, but has no obvious influence to ALP activity.

Objective   To compare the periodontal indices and Porphyromonas gingivalis(P. gingivalis) between the use of self-ligating brackets and conventional brackets. Methods   Thirty patients were divided into 2 groups(n=15). Self-ligating brackets were used in the experimental group. Conventional brackets were used in the control group. Cli-nical periodontal indices, including plaque index(PLI), gingival index(GI) and probing depth(PD) of observed teeth were examined at three different time points: Before orthodontic treatment, the first month after treatment and the third month after treatment. Subgingival plaques were collected simultaneously at each time point. The number of total bac-teria and P. gingivalis in each sample were detectd and quantitated by real-time quantitative polymerase chain reaction, the percentage of P. gingivalis in total bacteria was obtained. Results   Before treatment, the periodontal indices and the percentage of P. gingivalis in total bacteria had no difference between the two groups(P＞0.05). After 1 and 3 months respectively, the periodontal indices and the percentage of P. gingivalis in total bacteria increased with time(P＜0.05) and were obviously lower than those of the control group(P＜0.05). Conclusion   Compared with conventional brackets, the self-ligating brackets are better for periodontal health. But it is adverse effect on oral health.

Objective   To compare the fracture resistance of roots filled with three different root canal filling tech-niques. Methods     Forty extracted single-rooted permanent teeth were instrumented and randomly divided into four groups. Three experimental groups were filled with lateral compaction technique, vertical compaction technique and single-cone technique, respectively. No filling was performed in control group. All specimens were subjected to a vertical load to cause vertical root fracture. The force required to fracture was measured and the fracture lines was classified. Results   Three experimental groups exhibited higher mean fracture load values than that of control group (179.93 N±34.03 N). There was no significant difference among the three experimental groups, and the mean fracture load values were (210.04±64.57), (232.55±50.74), (216.80±78.03) N, respectively. Eighty-five percent of root frac-ture lines were found in the bucco-lingual direction. Conclusion   Root canal filling alone can’t influence the root strength significantly. There is no difference in root strength after three canal filling techniques.

Objective   The purpose of this study was to investigate the influence of cryogenic treatment and age-hardening heat treatment on the micro-Vicker’s hardness of palladium-silver dental alloys. Methods     A low-gold content dental casting alloy composed of Ag-Pd-Cu-Au was prepared for this study. Experimental specimens according to standard requirements were prepared following a standard dental laboratory casting procedure, cast specimens were heated to 900 ℃ and quenched in ice water. The specimens were then divided into 4 groups. They were subsequently subjected to different treatments, including age-hardening heat treatment, cryogenic treatment, heat treatment combined with cryogenic treatment. The non-treated group was used as control. The micro-Vicker’s hardness value was examined. The significance of correlation was analyzed. Results   The micro-Vicker’s hardness of specimens after age-hardening heat treatment, cryogenic treatment, heat treatment combined with cryogenic treatment increased by 129%, 13% and 141%, respectively, compared with that of the non-treated control group. Conclusion   Age-hardening heat treatment and cryogenic treatment were effective in elevating the hardness of Ag-Pd-Cu-Au alloy.

Objective   To evaluate the expression of cytokeratin 19(CK19) and connexin 43(Cx43) in various stages of oral carcinogenesis and investigate the relationship of CK19 and Cx43 in the process of oral cancer. Methods     4-nitroquinoline-1-oxide(4NQO) was used to induce oral carcinogenesis in the mucosa of SD rats and immunohistoche-mical technique was used to study the expression of CK19 and Cx43 in various stages of oral carcinogenesis. Results   The CK19 positive staining were distributed in the basal cell layer in the normal rat lingual mucosa. While CK19 positive staining were distributed in cytoplasm of supra-basal layers in the mild dysplasia, moderate dysplasia and severe dysplasia. In oral squamous cell carcinoma(OSCC) tissue, CK19 were expressed in all the stratum of epithelium. The positive rate of CK19 in normal, mild, moderate, severe dysplasia and OSCC tissues were respectively 30.00%, 50.00%, 58.33%, 80.00%, and 91.67%. With the lesions getting worse, the positive rate and the intensity of CK19 raised significantly(P<0.05). In normal tongue mucosa, Cx43 proteins were mainly expressed in the membrane of the epithelial cells of the rat tongue. It was weakly positive in the basal cell layer, increased in the stratum spinosum and stratum granulosum, and negative in the stratum corneum. Compared with normal epithelia, the expression of Cx43 in dysplastic and OSCC epithelia decreased significantly. The positive rate of Cx43 in normal, mild, moderate, severe dysplasia and OSCC tissues were respectively 100.00%, 85.71%, 66.67%, 40.00%, and 33.33%. The expression of Cx43 was significantly decreased with severity in-creasing(P<0.05). Conclusion   The expression of CK19 protein significantly increases with the development of rat tongue carcinoma, suggesting that CK19 is associated with carcinogenesis. The expression of Cx43 protein dramatically decrease with the development of rat tongue carcinoma, suggesting that the abnormal expression of Cx43 protein is associated with oral mucosa carcinoma origination. The ex-pression of CK19 and Cx43 has negative correlation. Combined detection of CK19 and Cx43 has an important role in the early diagnosis of OSCC and can help to improve the sensitivity and specificity of the early diagnosis of OSCC.

Objective   To investigate the effects of the leaching liquids of 4 differents kinds of dental alloys(Au alloy, Ag-Pd alloy, Co-Cr alloy, Ni-Cr alloy) on apoptosis related gene and protein of fibroblast L929. Methods     The L929 cells of mouse were treated in vitro with leaching liquids of 4 different kinds of dental alloys, Au alloy(group A), Ag-Pd alloy(group B), Co-Cr alloy(group C) and Ni-Cr alloy(group D). The RPMI1640 cell medium containing 10% fetal calf serum was served as a control(group E). The effects of these alloys on the expression of caspase-3, 8, 9 of L929 cells were examined by reverse transcription-polymerase chain reaction(RT-PCR) and immunohistochemistry method. Results   After 48 h culture, the mRNA levels of caspase-3 and caspase-9 demonstrated sig-nificant differences between the groups expect group A and group E. The mRNA levels of caspase-8 had no change in all groups. The expression of caspase-3 and caspase-9 were significant differences between the groups expect group A and C, group B and D. The expression of caspase-8 had no change in all groups. Conclusion   The leaching liquids of 4 different kinds of dental alloys expect Au alloy may induce cell apoptosis through mitochondrion pathway.

Objective   To investigate the promotive effect of transplantation of bone morphogenetic protein-2(BMP-2) gene transfected bone mesenchymal stem cells(BMSCs) compounded with injectable bone tissue engineering scaffold material Pluronic F-127 on bone regeneration in rabbit mandibular distraction osteogenesis(DO). Methods     Forty-eight New Zealand’s white rabbits were randomized into four groups with twelve in each. All the objects were prepared into DO surgical model. On the 2nd day of consolidation, group A, B, C and D were injected with the same amount of 200 μL of the compound of BMP-2 gene transfected BMSCs with Pluronic F-127, the solution with BMP-2 gene trans-fected BMSCs, the solution of BMSCs and physiological saline at distraction zone, respectively. Two halves of the ob-jects of all groups were sacrificed at the end of 2nd and 6th week consolidation, respectively. And the specimens of right mandible were prepared for radiological, histomorphological and immunohistochemical examinations to evaluate bone regeneration. Results   Both radiological and immunohistochemical images were analyzed and processed with pro-fessional software. At the end of 2nd and 6th week consolidation, the bone mineral density and the expression of BMP-2 protein in distraction area of group A were significantly higher than those of B, C, D group(P<0.01). Group B was significantly higher than that in group C and D(P<0.01). There was no significant difference between group C and D(P>0.05). And the regeneration quality of distraction zone in group A and B were better than those in group C and D, just as that of group A better than group B. Conclusion   The transplantation of BMP-2 gene transfected BMSCs compounded with Pluronic F-127 could effectively pro-mote bone regeneration in rabbit mandibular DO.

Objective   To compare the effects of dexmedetomidine and midazolam with fentanyl with anticipated difficult intubation during awake blind nasal intubation on respiration and hemodynamics of patients. Methods     Forty patients(ASA class Ⅰ toⅡ) undergoing selective oral and maxillofacial surgeries with anticipated difficult intubation were enrolled in the study. The patients were randomly assigned into two equal groups. Experimental group received dexmedetomidine, control group received midazolam and fentanyl. The Ramsay sedation scores, mean artery pressure(MAP), heart rate(HR), respiratory rate(RR) and blood oxygen saturation of pulse(SpO2) were recorded at baseline(T1), beginning to intubate(T2), 10 min after beginning to intubate(T3), 20 min after beginning to intubate(T4), and after intubation(T5). The operative time for intubation, intubation times, success rate of intubation, the anesthetic effects and complications were recorded. Results   The success rate in the experimental group was significantly higher than that in the control group(P<0.05). Intubation times in the experimental group was less than that in the control group(P<0.05). The incidence of complications such as nausea, vomiting, cough and throat unwell  in the control group was higher. Compared with the T1, RR decreased at T2 in the control group, but RR increased significantly at T4 and T5. RR and SpO2 had no significant change in the experimental group. Compared with T1, MAP and HR increased at T3, T4 and T5 in the control group(P<0.05). MAP and HR showed no significant variations in the experimental group(P>0.05). The Ramsay sedation scores in the control group were lower than those in the experimental group(P<0.05). Conclusion   Appropriate application of dexmede-tomidine can be safer and more effective than midazolam with fentanyl for awake blind intubation.

Objective   To evaluate the effect of furcal perforation treated with iRoot BP. Methods     Forty newly extracted human maxillary and mandibular molars were collected. Holes in diameter of 2 mm were prepared at the roof of the central pulp cavity of 36 samples with high speed round ball diamond in order to make perforated model, and then equally and randomly divided them into two groups. The other intact four samples were used as the negative controls. In the experimental groups, group A were repaired by iRoot BP, group B were repaired by mineral trioxide aggregate（MTA）. Three samples in each group were observed under scanning electron microscope（SEM）, and micro-leakage of others was tested by measuring the concentration of leaked glucose with the enzymatic glucose oxidase-peroxidase（GOD-POD） method. Results   Microleakage of group B was higher than group A and had statistical difference（P<0.05）. The dentin and iRoot BP contacted more closely in group A, some gaps existed between the dentin and MTA in group B. Conclusion   For repairing furcal perforation, the effect of iRoot BP is better than that of MTA.

Objective   To find the longitudinal genetic effects on mandibular position in mixed dentition. Methods     The sample used in this study consisted of lateral cephalograms of eighty-nine pairs of female twins in Beijing. With a mixed longitudinal method, the effective twins were 183 pairs(monozygous 110 pairs and dizygous 73 ones). The genetic and environmental effects on mandibular position were analyzed by statistical methods in female twins from six to twelve years old. Results   Statistical comparisons revealed significant(P<0.05) environmental effects on the angles(ArGo’Me, SArGo’, SN-MP, FH-MP, PP-MP), the depths(L1, L2, L3), and the heights(H1, H3) of mandibular; whilst genetic effects on the angle(NSAr) and the heights(H1, H2, H3, H4)(P<0.05); and family inheritance effects can be founded in the angles(ArGo’Me, SN-MP, NSGn, SGn-FH)(P<0.05). Conclusion   The effect of inheritance on mandibular position is strong, while environmental impact is relatively weak. Stronger genetic influence on heights is shown than that on depths. The environmental influence on depths and heights is different. Using Ba as a reference, the depth of the chin is the most subjective to environment change, then the mandibular angle, and the condyle is the least. Using N and S as references, the environmental influence on heights showed different order from the most to least changeable: The mandibular angle, the condyle and the chin. In later stage of our observation, the mandibular morphology and growth type might be family inherited. For environmental influences plays important roles on mandi-bular position, these findings can be used in orthodontic treatment planning.

Objective  To assess the efficacy of Dexamethasone(DM) pericoronal injection for the control of swelling and trismus caused by impacted mandibular third molars extraction. Methods  Cochrane, PUBMED, EMBASE and CBM were searched for eligible studies. Hand-searching included references of the included studies and Chinese den-tal journals. Risk of bias of the included studies was assessed by two reviewers independently using Cochrane Colla-boration’s tool, and data extraction was done by them. Meta-analysis was delivered with Revman 5.1. Results  Seven randomized controlled trials, involving 684 participants, were included. Six of them had moderate risk of bias and one had high risk of bias. Meta-analysis showed that DM pericoronal injection could relieve trismus by 6.77 mm(P=0.02) within 1-2 days after the surgery. It could also reduce 51% of the risk of moderate-severe trismus(P<0.000 01) and could significantly control facial swelling(P<0.05). There was no differences between 4 mg and 8 mg DM(P>0.05). Conclusion    Periodontal injection of 4-5 mg DM could control facial swelling and trismus following impacted mandi-bular third molar extraction. But more randomized controlled trials are needed.

Objective  To investigate the relationship between the stages of calcification of the third molar and age among children in Chengdu. Methods  The study subjects consisted of children between 2009 and 2011 at the Department of Orthodontics, West China Hospital of Stomatology, Sichuan University. Panoramic radiographs were ob-tained. The stages of calcification of the third molar were analyzed by Demirjian’s method. The development of the third molar between the male and female was evaluated by independent samples t-test analysis. The Spearman rank correlation was applied to analyze the stages of calcification of the third molar and chronological age. Results  The development of the third molar of the male was different from that of the female at stage A of calcification of the third molar(P=0.026). The Spearman rank correlation coefficient revealed highly significant relationships between the stages of calcification of the third molar and chronological age of the three groups（male, r=0.808, P=0.000; female, r=0.729, P=0.000; all, r=0.760, P=0.000）. Furthermore, the linear regression equations were established as follows: Yall=4.898+2.036X; Ymale=4.987+2.046X; Yfemale=4.819+2.036X. Conclusion    The stages of calcification of the third molar may be an available indicator in judging chronological age of teenager.

Objective  To investigate the pulp prognosis and influence factors of dentin-fractured teeth. Methods  Case records of dentin-fractured teeth treated with indirect pulp capping and with more than 2 years follow-up were collected. The data related to trauma information and pulp prognosis were recorded and the influence factors were ana-lyzed by Logistic regression. Results  This study consisted of 205 cases with 242 dentin-fractured teeth. Among 242 teeth, pulp necrosis occurred in 78 teeth（32.2%） and pulp calcification occurred in 3 teeth（1.2%）. The success rate of indirect pulp-capping on dentin-fractured teeth was 67.8%. During observation period, 141 out of 177 young per-manent teeth completed root development. The extent of fracture close to pulp was an indicator for pulp prognosis （P=0.001）. Conclusion    The prognosis of indirect pulp-capping on dentin-fractured permanent teeth is good. The extent of fracture close to pulp should be considered to evaluate the prognosis of the pulp.

Objective  To investigate the life quality and their influence factors in cleft lip and palate parents and to provide evidences for improving the life quality of the parents. Methods  One hundred and forty-three parents whose children accepted the primary surgery of cleft lip and palate were selected as the case group, and 109 normal adults as the control group. Both groups were investigated by 3 questionnaires that included questionnaire of general status, generic quality of life inventory-74(GQOLI-74), social support rating scale(SSRS). The results of two groups were analyzed and the influence factors on life quality were studied by stepwise multiple regression analysis. Results  1)The scores of the life quality, mental function, social function, material life in the case group were significantly low com-pared with the control group(P＜0.05). 2)The social support total scores, subjective support and utilization of social sup-port were lower than the control group(P<0.05). 3)Social support, objective support, subjective support positively correlated with life quality scores and every dimension score in the case group. 4)The relevant factors affecting life quality were social support and income. Conclusion    The life quality and social support of cleft lip and palate patients is poor, we should give more support and help to improve their life quality.

Objective  To explore the secondary correction demand rule for unilateral cleft lip patients. Methods  The population in parts of Henan province were investigated by census method. The unilateral cleft lip patients under-went the primary correction were selected and be photographed, and 100 patients were selected randomly into study. The subjective satisfaction for the patients’ facial appearance was evaluated by three groups: Professional group(cleft lip and palate specialist), non-professional group(the hospital administrative staff), and family members of patients group. The facial symmetry rate was measured for the patients with consistent subjective evaluation. Results  The rate of facial symmetry and subjective evaluation was not convergence. The subjective evaluation disaffect rates of profes-sional and non-professional groups were higher than that in family members of patients group(P<0.05). Conclusion  The rate of facial symmetry is not the most suitable method to evaluate the demand of the secondary correction for unilateral cleft lip patients.

Objective  To investigate the effect of Porphyromonas gingivalis lipopolysaccharide（LPS） on proliferation and inflammatory factors expression of human periodontal ligament stem cells（HPDLSCs）. Methods  HPDLSCs were cultivated and identified. Experiment was divided into 3 groups according to culture solution: Group A with α-MEM culture solution containing 10 μg•mL^-1 LPS, group B with supernatant fluid containing 10 ng•mL^-1 LPS stimulated mono-cyte, group C with α-MEM culture solution. The proliferation ability of HPDLSCs was analyzed by MTT assay. The ex-pression levels of interleukin-1β（IL-1β）, interleukin-6（IL-6）, tumor necrosis factor（TNF-α） mRNA of HPDLSCs were detected by reverse transcriptase polymerase chain reaction（RT-PCR）. Results  HPDLSCs had clonality, bone and fat differentiation ability. Compared with group C, the proliferation ability of HPDLSCs of group A and group B was sig-nificantly inhibited, and the proliferation ability of HPDLSCs of group B were more significantly inhibited than that of group A（P<0.05）. The expression of IL-1β, IL-6 and TNF-α mRNA of group A and group B increased compared with the control group, and the expression of IL-1β, IL-6 and TNF-α mRNA of group B increased more than that of group A（P<0.05）. Conclusion    Porphyromonas gingivalis may inhibit the proliferation of HPDLSCs directly or indirectly through LPS and increase expression of inflammatory factor, exacerbate periodontal inflammatory tissue damage and delay the self-repairing of periodontal tissue.

Objective  To evaluate the feasibility of identifying oral mucosa pathogenic bacteria by comparing the metabolic profiling of Saccharomyces and try to find a convenient and rapid way to discriminate oral micro-organisms. Methods  Saccharomyces albicans ATCC 10231 and Saccharomyces tropicalis ATCC 13803 and Saccharomyces gla-brata ATCC 15126 were respectively inoculated in sabouraud medium. The growth quantity were measured periodically by a spectrophotometer. And the growth curves of the inoculated bacteria were completed. The culture solutions in sta-tionary phases of the three bacteria were respectively tested with 1H-nuclear magnetic resonance（1H-NMR） spectros-copy. The data of 1H-NMR spectroscopy results were analyzed by principal components analysis（PCA）. Results  The PCA showed respectively a obvious clustering phenomena and the points of every two groups’ data stayed separately. Therefore, the NMR-based metabonomics profiles could discriminate the three kinds of mucosa pathogenic bacteria. Conclusion    The metabonomics can be expected to be a kind of promising useful method in quick discrimination of oral pathogenic bacteria.

Objective  To compare the cytocompatibility of two kinds porous bioactive glass-ceramic made by same raw materials. Methods  Apatite/wollastonite bioactive glass-ceramic（4006） were prepared by sol-gel method, and bioactive glass（45S5） were prepared by melting method. Bone marrow stromal cells（BMSCs） were cultivated, differen-tiated and proliferated into osteoblasts, from a rabbit’s marrow in the differentiation culture medium with active func-tion. The viability of BMSCs cultivated with extraction of these two kinds of biomaterial, which could represent the cytotoxicity effect of 4006 and 45S5 against BMSCs, was evaluated by the MTT assay. BMSCs were seeded and co-cultivated with two kinds of biomaterial scaffolds respectively in vitro. The proliferation and biological properties of cells adhered to scaffolds were observed by inverted phase contrast microscope, scanning electron microscope（SEM）, and environmental scanning electron microscope（ESEM）, and a suitable cell amount for seeding on the scaffold was searched. Results  There was no difference on the viability of BMSCs only cultured for one day by complete extract of 4006 and culture medium（P>0.05）, but there was significant difference between them when the cells had been cultured for 3 days（P<0.01）. The extract of 45S5 had significantly higher cytotoxicity than extract of culture medium（P<0.01）. The BMSCs adhered, spread, and proliferated throughout the pores of the scaffold 4006, and the amount of cells adhered to 4006 was more than to 45S5. The adhered cells to 4006 increased with the rising amount of cells seeded. And 2×107 cells•mL-1 suspension resulted in the highest cell adherence during the comparative cell adherence test. Conclusion    Apatite/wollastonite bioactive glass-ceramic has good bioactivity and cytocompatibility. Therefore, it may have the potential to be a new cell vehicle for bone tissue engineering. And the suitable seeding cell amount of apatite/wollastonite bioactive glass-ceramic should be 2×107 cells•mL-1 or even more than that.

Objective  To evaluate the marginal adaptation between the new nano-hydroxyapatite composite resin and tooth. Methods  Thirty extracted healthy premolars were randomly assigned to three groups according to the ma-terial employed: New nano-hydroxyapatite composite resin（Group A）, Karisma composite resin（Group B）, and glass ionomer cement（Group C）. After the thermal cycling, the teeth were immersed in 2% methylene blue dye, and the depth of microleakage between the composite and tooth structure were observed. Results  The microleakage depth of group A, B and C were （1.20±0.81）, （1.94±0.70）, and （1.73±0.54） mm, respectively. No statistically significant differences were found among the three groups（P>0.05）. There was no significant difference in the degree of microleakage （P>0.05）. Conclusion  As a new dental restorative material, new nano-hydroxyapatite composite resin has good bon-ding performance to the tooth structure.

Objective  To explore the expression of Notch signaling receptors Notch1, Notch3 and its ligand Jagged1, Jagged2 in tongue squamous cell carcinoma（TSCC）. Methods  mRNA and protein expression levels of tissue samples from 74 cases of tongue cancer patients and human tongue cell line Cal-27 were detected by reverse transcriptase-polymerase chain reaction（RT-PCR）, immunohistochemistry and Western blot. Its relationship with cell proliferation and clinical pathology was analyzed. Results  mRNA and protein expression were detected in tongue cancer tissues, adjacent tissues and cell lines. Notch1 and Notch3 protein expression in tongue cancer was higher than the adjacent tissues. Jagged1 and Jagged2 protein expression in tongue cancer and adjacent tissues had no difference. Notch1 and Notch3 protein had correlation with tongue cancer clinical staging. Pathway protein expression had no correlation with pathological grade, age, gender. Notch1 protein expression in lymph node metastasis-positive cases was higher than in lymph node metastasis-negative cases. The expression of Notch3 and Jagged2 had correlation. Jagged1 expression grade in metastasis-positive cases was higher than in negative cases. Conclusion    Notch signaling molecules have active expression in TSCC and may play important roles in tongue cancer development.

Objective  The theory of strain energy density（SED） was combined with finite element analysis to investigate alveolar bone remodeling of the mandibular first molar with different levels of periodontal attachment under mastication loading. Methods  Three-dimensional finite element models of the mandibular first molar with different levels of periodontal attachment were established. Based on SED theory, the user material subroutine（UMAT）（used by ABAQUS software） was developed by ourselves to simulate the remodeling process of mandibular bone. The stress distributions and bone density changes were analyzed under different mastication loading. The influence of loading magnitude on alveolar bone remodeling with different levels of periodontal attachment was investigated. Results  The results showed that the neck of buccal, lingual regions and root apex area experienced a higher stress. The stress and the density of alveolar bone increased gradually with the enhancing of the bite force at the beginning. Then the density would appear declining when the bite force exceeded the extreme load. The extreme load reduced from 420 N to 240 N with the periodontal attachment falling from normal to 1/2 of root length also. And the remodeling rate of the bone was faster as the loading increasing. Conclusion    The capability of the periodontal tissue for supporting the teeth will drop gradually as the periodontal attachment level dropping. And the decline of bone density also appeared in earlier time. The change of density is associated with mastication loading during the bone remodelling. And reducing the occlusal force properly to the molar with different attachment level is benefit for clinical treatment and prognosis of periodon-tal disease.

Spinal muscular atrophy is one rare type of autosomal recessive disorder. The disease is characterized by the progressive degeneration of spinal cord anterior horn motor neurons and brainstem motor nuclei, which leads to muscle atrophy and paralysis. One case of spinal muscular atrophy with open bite was reported here.

Primary salivary duct carcinoma(SDC) featured with giant cell tumor(GCT) is a extremely rare, relatively new understanding lesion and its histogenesis has not been fully defined. This paper reported a case of SDC associated with GCT, its clinical, histopathologic features and histological origin were discussed in combination with literature review.

Combined with a case, the mechanical analysis and clinical application of micro-implant combining with utility arch were introduced in this paper.

Articulators have been widely used by clinicians of dentistry. But routine articulator mounting is still controversial in orthodontics. Orthodontists oriented by gnathology approve routine articulator mounting while nongna-thologic orthodontists disapprove it. This article reviews the thoughts of orthodontist that they agree or disagree with routine articulator mounting based on the considerations of biting, temporomandibular disorder(TMD), periodontitis, and so on.

Medicine has dual features of humanities and natural science. Thus, it is necessary for the development of modern higher education to carry out the humanistic quality education to medical students. It is not only the req-uest of modern medical model and medical development, but also the urgent need of the development of medical and health. Besides, it plays an important part in the cultivation of medical students. In the face of the urgent need of cultivation for comprehensive humanistic quality of oral medical students, West China School of Stomatology, Sichuan University, led in the cultivation method which is oriented by competency, give some suggestions to deal with students’ lack of language ability, humanistic concern to patients and aesthetic accomplishment. And it has already achieved a better teaching effect.