Just like other subjects in medicine, orthodontics also uses some vague concepts to describe what are difficult to measure quantitatively. Anchorage control is one of them. With the development of evidence-based medicine, orthodontists pay more and more attention to the accuracy of the clinical evidence. The empirical description of anchorage control is showing inadequacy in modern orthodontics. This essay, based on author’s recent series of studies on anchorage control, points out the inaccuracy of maximum anchorage concept, commonly neglected points in quantitative measurement of anchorage loss and the solutions. It also discusses the limitation of maximum anchorage control.

Objective To reconstruct mandibular defect using tissue engineering bone with bone marrow stem cells （BMSCs） cell sheets and investigate the effect of cell sheets on osteogenesis. Methods BMSCs were isolated with the method of density gradient centrifugation from canine and cultured. BMSCs were induced to differentiate to osteoblasts. BMSCs induced were fabricated to BMSCs cell sheets. The poly（lactic-co-glycolic acid）（PLGA） wrapped with cell sheets were implanted into the mandibular defect in the left side（experimental side）. PLGA wrapped without cell sheets were implanted into the right side（control side） of mandibles. 16 dogs were evenly divided into 4 groups, and one group of them was executed in 4, 8, 12, 16 weeks for gross investigation and histological observation. Results The osteogenesis of experimental side was better than that of control side. 16 weeks after implantation, most areas ofthe mandibular defect were replaced by fresh bone tissue. Compact bone similar to normal bone tissue formed in thelingual defect of mandible and had bony union with the bone stump. The optical density of the fresh bone in the experimental side was higher than that of the control side, there was a significant difference between the two methods（P<0.05）. Plenty of lamellar bones formed in experimental side and Haversian system, as well as red marrow, wereobserved. Conclusion Tissue engineering bone with the structure of lamellar bones can be formed by the technology of BMSCs cell sheets.

Objective To observe the role of the Hedgehog（Hh） genes in the proliferation of osteoblasts upon mechanical tensile strains. Methods Primary osteoblasts harvested from newborn rat calvarial bone were subjected to 3% and 6% elongation of tensile stretches using Flexcell 4000TM strain unit. The cultures were also treated with either recombinant N-terminals Sonic Hedgehog（N-Shh） or cyclopamine（cy）, a Hh inhibitor or gadolinium（GdCl3 ） , an inhibitor of stretch-activated channels. The proliferation of osteoblasts was quantified by cell counting, methyl thiazolyl tetrazolium（MTT） and cell cycle detection via flow cytometry. Statistical analysis was performed using SAS 8.0 software package. Results The tensile strain, especially under 6% elongation, promoted osteoblast proliferation. Stretching force could also promote the proliferation even when the cells were treated with cy, but this effect was suppressed by GdCl3. Conclusion The induced proliferation of osteoblasts by mechanical stretched is mediated at least in part by Indian Hedgehog（Ihh） signaling.

Objective In situ, real timely and dynamically monitoring the processes of theaflavin（TF）, curcumin （Cur）and cyanidin（Cy）binding to human whole saliva（WS）surface has been investigated by surface plasmon resonance （SPR） technique at the molecular level. Methods The affinity between pigments and WS, association rate constant （ka ） , dissociation rate constant（kd）, association equilibrium constant（KA） and dissociation equilibrium constant（KD） of
pigments binding on WS surface had been determined by SPR and the Langmuir model as well as the Freundlich model. The data were analyzed by one-way ANOVA and SNK-q test. Results There were significant differences among TF, Cur and Cy in ka, kd, KA and KD（P<0.05）. Our results showed that the adsorption isotherm of pigments on WS surface could be better described by the Freundlich model than the Langmuir model. The pigments adsorption on WS surface was dominant by specific interactions, such as hydrogen bonding. The affinity of pigments to WS were TF>Cur>Cy（P<0.05）, as evidenced by the rate constants and equilibrium constants. Conclusion Compared with Cur and Cy, TF shows much higher adsorption capacity on WS surface, suggesting the importance of the hydroxyl group in pigment/protein interactions.

Objective To compare the hardness development of dual-cured self-adhesive and universal resin cement in simulated root canal. Methods The light-proof half-cylinder steel slot with one end open were syringed and filled respectively by self-adhesive A（RelyX Unicem）, B（BisCem） and universal C（DUOLINK） resin cements, then the open end of slot was irradiated directly by a light unit for 20 s. Specimens were stored in a light-proof box for 0.5 h, Knoop microhardness was measured along the vertical surfaces of specimens from 1 mm to 10 mm depth at 1 mm intervals. The same measurements were taken at 24 h and 120 h after irradiation. Data were analyzed by One-way ANOVA. Results Hardness of each group decreased with the increase of simulated canal depth（P<0.001）, however hardness showed no significant change between 5 mm and more depth of group A, between 4 mm and more depth of group B and C. The increase of hardness for each group was more rapid within 0.5 h after irradiation, thereafter the hardness increased gradually to maximum at 24 h. At 120 h after irradiation, hardness of group C was greater than that of other two groups at more than 1 mm depth（P<0.001）. Conclusion Under dual-cured condition, hardness has significant difference between self-adhesive and universal resin cements, however their hardness development is similar.

Objective To observe the activity of superoxide dismutase（SOD） in rabbit periodontitis model in normoxia and hypoxia environment, and to research the pathogenesis of periodontal diseases at high altitude. Methods Fourty male rabbits were randomly divided into four groups: Normoxia control group, normoxia periodontitis group（periodontitis models）, hypoxia control group, hypoxia periodontitis group（periodontitis models）. The periodontitis models were established by ligating the two central incisors of mandible and raised by periodontitis diets. The weights of four groups were dynamically observed. After eight weeks, the clinical periodontal indexes and the activity of total-SOD（TSOD） in blood serum and gingival tissues in all groups were detected. Results The activity of T-SOD of hypoxia periodontitis group was significantly lower than normoxia periodontitis group and hypoxia control group（P＜0.05）, the  weights and clinical periodontal indexes were also dramatically different（P＜0.01）. The activity of SOD in serum was positively correlated with the gingival tissues（r=0.846, P<0.01）, and they both negatively correlated with AL（r=-0.980, -0.804, P<0.01）. Conclusion The growth state of the body and the balance of bioconversion were affected in hypoxia environment when exposed at high altitude. The activity of SOD in total body and local tissues were decreased, thus the superoxide free radicals were accumulated in the body, especially in local periodontal tissues. Therefore it can accelerate and aggravate the destruction of periodontal tissues.

Objective The soluble protein recombinant Streptococcus mutans surface protein（rPAc） was expressed in Escherichia coli（E.coli） after the optimization of inducing conditions. The antiserum against rPAc was obtained by immunizing mice with the purified rPAc. Methods The soluble expression of rPAc in E.coli was further optimized by means of different culture conditions. Polyclonal antibody was made by immunizing mice with purified rPAc. Western blot and enzyme linked immunosorbent assay（ELISA） were carried out to identify the immunocompetence of the antibody. Results The highest soluble expression level of rPAc was obtained at Luria-Bertani（LB） medium（pH=7.2） when optical density（OD600nm） was 0.6 after being induced at 30 ℃ for 4 h and the concentration of isopropyl β-D-1- thigalactopyranoside（IPTG） was 1.0 mmol·L-1. The titer of the mice antiserum against rPAc was about 1∶6 000 by ELISA analysis, and rPAc could be specifically recognized by Western blot analysis. Conclusion This study proved that rPAc can be effectively expressed as a soluble form in E.coli, and the high specific polyclonal antibody of rPAc was proved to be prepared, which shed light on further research of DNA prime-protein boost inoculation.

Objective To study the interleukin-8（IL-8） levels in gingival crevicular fluid（GCF） of porcelain teeth
coated with Ni-Cr, Co-Cr or gold alloy at different time periods, and to uncover the degree of stimulation by these
alloys on gingiva at different time periods. Methods 45 cases of porcelain teeth coated with Ni-Cr, Co-Cr or gold
alloy were selected randomly, with 15 cases in each group. Sandwich enzyme-linked immunosorbent assay（ELISA） was
used to determine the concentration and total amount of IL-8 in GCF. The assay was done before treatment, as well
as at 1, 3 and 6 months post-treatment. Results The total amounts of IL-8 and GCF volume in the Ni-Cr alloy
coated porcelain teeth were higher in different time period than those before treatment（P<0.05）. However, the IL-8
levels in Co-Cr and gold alloy coated porcelain teeth returned to pre-dental restoration after 3 months. Otherwise,
the levels of IL-8 concentration in GCF showed no significant difference among the three different alloys coating at
different time periods. Conclusion IL-8 is an important cytokine during tissue inflammation. Therefore, the level of
IL-8 in GCF is a useful criteria for the evaluation of stimulation degree on gingiva by different alloy coating materials
in porcelain teeth. The clinical choice of different alloy coating for porcelain teeth should be considered accordingly.

Objective To investigate the prevalence and treatment of radix entomolaris（RE） in mandibular first molars. Methods 378 cases of mandibular first molars with root canal therapy were collected. The case included clinical records and periapical radiographs of preoperative, intraoperative and postoperative. The root number, root canal number and root canal therapy were investigated. Results The RE prevalence of mandibular first molars was 26.98％ （102/378）. Both gender and bilateral occurrence of RE did not show a significantly difference（P>0.05）, but there was a significantly greater incidence of instrument separation, lateral perforation and underfill of the root canals in RE than other canals in mandibular first molars（P<0.05）. Conclusion The RE prevalence of mandibular first molar is high and there is a significantly greater incidence of instrument separation, lateral perforation and underfill of the canals in RE than other canals in mandibular first molars.

Objective To evaluate the value of cone beam CT（CBCT） in the treatment of jaw bone cyst. Methods Twenty-five patients with jaw bone cyst were included, which were examined by CBCT as an addition of panoramic radiography. Through CBCT, the information about the three-dimensional location, the bone wall of cyst and the relationship between cyst, teeth and some other important anatomical structures were studied, surgical preparations and treatments followed accordingly. Results The CBCT images clearly demonstrated detailed information about the cyst, which was verified in the operation and helpful to the surgical preparation and treatment. Conclusion CBCT is more advantageous in the diagnosis and treatment of the jaw bone cyst than traditional panoramic radiography and periapical film.

Objective To assess the reporting quality of randomized controlled trials（RCT） related to dentine hypersensitivity which were published between 2000 and 2009 in nineteen Chinese stomatological journals, learn the current status and the influence factors of reporting quality of the dentine hypersensitivity RCT, and determine whether they can provide high quality evidence clinically. Methods A handsearching of nineteen Chinese stomatological journals to identify dentine hypersensitivity RCT which were published between 2000 and 2009 and labeled“random”. Assess the reporting quality of these RCT by Consolidated Standards of Reporting Trials（CONSORT） statement and then analyze the influence factors of reporting quality by univariate and multivariate analyses. Results We identified 61 dentine hypersensitivity RCT, among which 45 belonged to journals of Chinese scientific study statistical source and 16 belonged to journals of non-statistical source. The reporting quality of dentine hypersensitivity RCT was not high at large and the CONSORT score was 8.1±2.4 on average. Multiple linear regression showed that the score of improved Jadad scale（t=4.656, P=0.000） was the main influence factor of reporting quality of dentine hypersensitivity RCT. The better the intrinsic authenticity was, the higher the reporting quality would be. Conclusion Currently, reporting quality of Chinese dentine hypersensitivity RCT needs to be improved. In order to improve the reporting quality of dentine hypersensitivity RCT, experts in stomatology should not only improve experimental design before experiments, but also write papers in accordance with CONSORT statement.

Objective To assess the safety, effectiveness and influential factors of oral midazolam sedation for reducing dental fear in children with dental fear. Methods 30 children with traumatic dental experience, who were classified as 1 by Frankl behavior rating scale, were included in the study. Each child was treated under sedation with oral midazolam（0.5-1.0 mg·kg-1）, and totally 46 person-time sedation treatments were conducted. At each visit, heart rate, arterial oxygen saturation, persistent period and treatment types were recorded. Treatment performed was rated by Houpt scale. Telephone following up was performed to record the side effects 24 h after treatment. Results In all of the 46 person-time treatments, the heart rate, arterial oxygen saturation levels were within acceptable clinical limits. 37 person-time planned treatments（80.4％） were completed satisfactorily. Oral sedation was ineffective in 9 person-time treatments（19.6％）, and only a part of planned treatments were completed. Dysphoria after treatment is the main side effect. Children over 3 years old had a high success rate than those under 3 years old. And the success rate of treatment had no relation with sex, dose and treatment types. Conclusion Oral midazolam could be a safe and acceptable approach of sedation for pediatric dental patients with dental fear, especially to the children over
3 years old.

Objective To study the characteristics of the arch form of skeletal Class Ⅲ malocclusion and provide references for diagnosis and treatment plan. Methods 7 indexes in dental casts of 47 patients with skeletal Class Ⅲ malocclusion and 50 individuals with normal occlusion were measured respectively. And differences between corresponding upper and lower measurements were calculated. Independent samples t-test was employed for comparing between the two groups by SPSS 17.0. Results Compared with normal occlusion sample, Class Ⅲ malocclusion group had smaller anterior segment lengths and larger canine angles（P<0.05）. Differences between upper and lower first premolar widths were larger in males with skeletal Class Ⅲ malocclusion. And differences between upper and lower anterior segment lengths were smaller in males with skeletal Class Ⅲ malocclusion（P<0.05）. Conclusion Arch widths of patients with skeletal Class Ⅲ malocclusion are basically normal. The lengths of anterior segment are smaller and the anterior arch forms are straighter.

Objective To evaluate the soft profile and hard tissue changes after maxillary protraction with skeletal anchorage implant in treatment of Class Ⅲ malocclusion during growth period. Methods 18 patients with skeletal Class Ⅲ malocclusion were treated with maxillary protraction for about 9 months, （3.5±0.1）N, with skeletal anchorage implant and face mask. Cephalometric records were analyzed to assess the changes of maxillo-facial structure of the hard and soft tissue before and after treatment. Results All patients’Class Ⅲ profiles were corrected. Maxillary growth increased, chin clockwise rotated, facial convexity angle increased, lower lip protrusion decreased. Facial vertical height ratio, nasolabial angle, upper lip protrusion and mentolabial sulcus changed unconspicuously. Upper incisors kept in sites, lower incisor upright, maxilla moved forwards. SNA, ANB significantly increased. SNB decreased and the mandible clockwise rotated. Conclusion The maxilla is effectively protracted without significant rotation by using skeletal anchorage implant. The undesired effects of conventional protraction therapies, such as labial tilt of upper anterior teeth and extrusion of the maxillary molars, are reduced or eliminated with skeletal anchorage implant. These effects can conspicuously correct profiles of the patients with skeletal Class Ⅲ malocclusion, make the profile more harmonious and
aesthetic.

Objective To study the clinical effect of root amputation in the treatment of periodontal/alveolar abscess teeth with one severe lesion root. Methods 30 periodontal/alveolar abscess teeth with one severe lesion root were chosen in the study. After root canal treatment, supragingival scaling, subgingival scaling and root planning, occlusal adjustment were done. Then the teeth were treated by root amputation. The clinical effect was evaluated 3 months, 6 months and 1 year after surgery. Results One year after surgery, 27 of 30 teeth were successful, 1 mandibular molar occurred root fracture, 1 mandibular molar was removed because of tooth loosening secondary to periodontal damage. 1 patient lost. Conclusion Root amputation is an effective solution of periodontal/alveolar abscess.

Objective To study the root canal curvatures of adolescents’maxillary first premolars in Guangdong province and the differences between male and female were studied. Methods 200 maxillary first premolars among adolescents in Guangdong Province（100 males and 100 females） were numbered in proper. After access preparation, a K-file was inserted into the canal until the tip of the file was just seen at the apical foramen. Then standardized periapical images were taken from mesial-distal and buccal-lingual directions with radio visio graphy. The angle of canal curvature（CCA） was determined according to the method described by Schneider. Then the curved canals whose angle were more than 5° were chosen, and the canal access angle（CAA）, curvature height（X） and curvature distance（Y） were determined according to the method described by Günday. Linear correlations of the measurements were analyzed. Results 59.21% of the total roots were curved in buccal-lingual directions. The incidence rates of males’and females’were 49.74% and 68.98%, respectively. 41.05% of the total roots were curved in mesial-distal directions. The incidence rates of males’and females’were 36.27% and 45.99%, respectively. 6.84% of the total roots were S-shaped curves. 4.15% and 9.63% of canals from male and female were S-shaped curves, respectively. The curvatures of single root canals between male and female had statistical differences in buccal-lingual directions （P＜0.05）. The curvatures of the lingual root canals from females in buccal-lingual directions and mesial-distal directions was higher than males’（P＜0.05）. The Y of buccal root canals in buccal-lingual directions and mesial-distal directions and the CCA of lingual root canals in buccal-lingual directions between male and female had statistical differences（P＜0.05）. The CAA of curved buccal canals and curved palatal canals from female and female had positive correlation with CCA and X（P＜0.01）, while negative correlation with Y（P＜0.05）. Conclusion There are curved root canals in buccal-lingual and mesial-distal directions in the maxillary first premolars, and some curved root canals were S-shaped. The curved canals incidence rate of females was higher than males.

Objective To explore an effective orthodontic method for treating impacted dilacerated maxillary central incisors. Methods 12 impacted teeth of 11 cases were chosen. The position of the impacted teeth and the relations with neighbour tissues were assessed by X-ray images, oral examination and plaster model, etc. The impacted teeth were induced to erupt with the closed-eruption technique and fixed orthodontic appliances, root canal therapy, apicoectomy and prosthetic treatment. Results 12 impacted teeth were moved into arches, and the occlusal relationship was normal. There were no root resorption or conglutination in those impacted teeth. The labial impacted teeth of nine cases had bigger labial crown torsion. The root apexes of four impacted teeth were palpable under mucosa of the labial sulcus and operated by root canal therapy and apicoectomy. One of them received prosthetic treatment. Others （five cases） hadn’t accepted root canal therapy, and were observed temporarily. The effects of two palatal impacted teeth was stable. Conclusion It was a good method to expand indication with sequence orthodontic treatment. The impacted dilacerated maxillary central incisors could be aligned with good esthetical and functional effect.

Objective To establish the three-dimensional model of human permanent premolars based on Microcomputed tomography（Micro-CT） data, and evaluate the efficiency quantitatively of two different instrumentations for root canal retreatment. Methods Forty extracted permanent premolars for the reason of orthodontic treatment were collected, prepared by using ProTaper Ni-Ti files and filled by cold gutta pertscha lateral condensation technique. The subjects were scanned by Micro-CT. Forty teeth were randomly divided into two groups and retreated by K-Flexo files and ProTaper Universal retreatment system respectively. Then all subjects were scanned again, and the mean percentage of remaining filling materials and the scores of remaining filling materials presented in upper, middle and apical 1/3 of the canal were calculated. Results Mean percentage of the remaining filling materials by K-Flexo files was lower than that by ProTaper Universal retreatment system（P=0.005）. The scores demonstrated that K-Flexo files had greater efficiency than ProTaper Universal retreatment system when retreating the apical 1/3 of canal（P<0.05）. Conclusion This study shows that both techniques could not remove filling materials completely.012, China）

Objective The purpose of this study is to assess the height and width of mandibular cross-sections and the thickness of cortical bone for young females in different vertical skeletal pattern by cone beam CT（CBCT） and determine the characteristics and differences of mandible among different vertical skeletal patterns. Methods A total of 64 females, aged from 19 to 40 years old, were enrolled from Department of Orthodontics of School of Stomatology of Shandong University. After examination with CBCT scan, they were divided into 3 groups according to the vertical skeletal patterns（14 in low-angle group, 31 in average-angle group and 19 in high-angle group）. The mandibular morphology was evaluated according to the height and width of the mandibular cross-sections and the thickness of cortices. SPSS 16.0 was used to analyze the characteristics and differences of mandible among different vertical skeletal patterns. Results The height of symphysis in the high-angle group was higher than that in the low-angle group, but the height of molars in the low-angle group was higher than that in the high-angle group（P<0.05）. In the regions of anterior teeth and premolars, the width of upper one third of the mandibular cross-sections in the low-angle group was significantly larger than those in the high-angle group, while in the symphysis and lateral incisors regions, the width of lower one third of the mandibular cross-sections in the low-angle group was larger than those in the high-angle group（P<0.05）.Except of the region of premolars, the cortical thickness of base in the low-angle group was significant thicker than those in the high-angle group（P<0.05）. In the regions of canine, premolar and molar, the cortical thickness of buccal upper one third in the low-group was thicker than those in the high-angle group, but in the regions of canine and the second molar, the cortical thickness of buccal lower one third in the low-angle group was thi-cker than those in the high-angle group（P<0.05）. In the regions of the symphysis, the cortical thickness of lingual lower one third in the low-angle group was thicker than those in the high-angle group（P<0.05）, but in the regions of premolar and molar of lingual upper one third in the low-angle group was thicker than those in the high-angle group（P<0.05）. Conclusion The height and width of the cross-sections of the body of mandible differed more than thickness of cortical bone among the three different vertical skeletal patterns. The height of cross-sections decreases gradually from the anterior region to the posterior region in three groups. The width of cross-sections in the low-group is thicker than those in other two groups. The thickness of cortical bones decreases successively from low, average to high angle group.

Objective To investigate the influence of carbon monoxide on the expression of adhesion moleculesstimulated by inflammatory cytokines on human gingival fibroblasts. Methods Human gingival fibroblasts were stimulatedwith 50 ng·mL-1 tumor necrosis factor（TNF）-α and 10 ng·mL-1 interleukin（IL）-1β concurrently in the presenceor absence of 500 μmol·L-1 carbon monoxide releasing molecule（CORM）. Expression of intercellular adhesion molecule（ICAM）-1, vascular cell adhesion molecule（VCAM）-1 at protein and mRNA level was examined by Western blot andreverse transcription polymerase chain reaction（RT-PCR）, respectively. Activity of transcription factor NF-κB was evaluatedby reporter gene assay. Results Expression of ICAM-1 and VCAM-1 on human gingival fibroblasts increaseddramatically after concurrent stimulation of TNF-α and IL-1β, while CORM inhibited the upregulation of ICAM-1 andVCAM-1. CORM decreased the activity of NF-κB stimulated by TNF-α and IL-1β. Conclusion Carbon monoxidecould be a promising way in treating of periodontitis.

Objective To make an animal periodontitis and atherosclerosis compound model, and to study the effects of periodontitis on atherosclerosis. Methods 36 Japan rabbits were randomly divided into four groups: Including periodontitis model group, periodontitis and atherosclerosis compound model group, atherosclerosis model group and control group. Periodontitis model was initiated by ligating floss around teeth cervical and oral inoculating with Porphyromonas gingivalis（P.gingivalis）. Atherosclerosis was established by single iliac artery of balloon-injured rabbit. Histopathological change of injured iliac artery was observed under optical microscope after hematoxylin-eosion stain. Elastica van Giesonstained sections were used for the morphometric analysis. We measured intimal and medial lesion areas in iliac artery cross-sections as well as the intimal/medial ratio（I/M）. We also analyzed P. gingivalis 16S rDNA amplification with nested-polymerase chain reaction（nested-PCR）, and detect systemic proinflammatory mediators with enzyme linked immunosorbent assay（ELISA）, including C-reactive protein（CRP）, interleukin-6（IL-6） and interleukin-1β（IL-1β）. Results The serum levels of CRP, IL-6 and IL-1β increased obviously among the compound model group than other groups（P<0.01）. Histopathological observation revealed the compound model group in I/M was bigger than other groups（P<0.01）. P.gingivalis 16S rDNA was detected among the periodontitis model group and the compound model group by nested-PCR. Conclusion Periodontitis may accelerate intimal hyperplasia in balloon-injured iliac arteries by upgrade of systemic inflammation factors and local bacterial infection.

Objective To determine the expression levels of calcium channel alpha-2-delta-1（Cavα2δ-1） subunit in trigeminal ganglia（TG） and trigeminal spinal subnucleus caudalis C1-C2 spinal cervical dorsal horn（Vc/C2） after infraorbital nerve（ION） ligation injury in relation to the development of neuropathic nociception. Methods Twelve male SD rats were divided into two groups randomly, with 6 rats for each. In the ligation group, the ION was ligated by chromic gut loosely. In the sham operation group, the ION was exposed under same procedure but not ligated. The behavioral tests were conducted before 1 d and after 3, 6, 9, 12, 15 d with calibrated von Frey filaments. Cavα2δ-1 protein levels in TG and Vc/C2 were measured with Western blots 15 days after surgery. Results Compared with the sham operation group, changes of allodynia to mechanical stimulation on the territory of ligated ION were found from
the 9th to 15th day after operation in the ligation group（P<0.05）. The expression levels of Cavα2δ-1 in TG and Vc/C2 after ION ligation injury upregulated significantly（P<0.01）. Conclusion The expression levels of Cavα2δ-1 in TG and Vc/C2 after ION ligation injury were upregulated and it may contribute to the pathogenesis of neuropathic nociception.

Objective The study is to observe the effect of nitric oxide（NO） donor and scavenger to the hypoglossal motor nucleus（HMN） activity and explore the underlying mechanism. Methods Male adult anesthetized Wistar rats were anesthetized. The activity of genioglossus（GG）, diaphragma, blood pressure（BP） and respiratory rate（RR）were recorded when constant microdialysis perfusion of artificial cerebrospinal fluid（ACSF） to HMN as control, followed with diethylamine NONOate sodium salt hydrate（DEA）, a NO donor, and 2-（4-carboxyphenyl）-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt（carboxy-PTIO）, a NO scavenger. Results Compared with ACSF, application of DEA and carboxy-PTIO at HMN increased and decreased the GG activity respectively and significantly（P<0.05）, mainly respiratory-related activity. The tonic GG, diaphragma activity, BP and RR had not been affected statistically between 30-120 min when microdialysis perfusion of both DEA and carboxy-PTIO were delivered. Conclusion Acting as an excitatory neurotransmitter of HMN, NO may contribute to the patency of upper airway physiologically.

Objective To study the effect of osteogenic inducer（dexamethasone, β-sodium glycerophosphate and Vitamin C） carried by gelatin sponge on healing and remodeling of tooth extraction sockets. Methods Fifty rabbits were selected. After extracting the first premolars of bilateral maxillary, the right side tooth extraction sockets were filled with gelatin sponge containing osteogenic inducer as experimental side, tooth extraction sockets on left side were
filled with gelatin sponge as control. Every ten rabbits were executed at the end of 1, 2, 4, 8, 12 weeks after tooth extraction. Bone density was measured through digital X-ray images. The specimens were examined by histology． The absorption height of alveolar bone at 12 weeks was measured. Results X-ray measurement showed that the bone density of experimental side was higher than that of control side at 2, 4, 8, 12 weeks, the difference had statistical significance（P<0.01）. The histology examination showed that new bone formation in tooth extraction sockets of experimental side was earlier than that in control side. The absorptional height of alveolar bone had significant difference between experimental side and control side（P<0.01）, of which experimental side was less. Conclusion Filling the osteogenic inducer in tooth extraction sockets can promote the healing and new bone formation and prevent from alveolar
bone absorption.

Objective  The aim of this study was to survey the influence of Toll-like receptor 2（TLR2） and Tolllike receptor 4（TLR4） repression to receptor activator of nuclear factor-κB ligand（RANKL） expression of human periodontal ligament fibroblasts（HPDLFs） under the stimulation of lipopolysaccharide（LPS）. Methods The level of RANKL in HPDLFs stimulated by 100 ng·mL-1, 1 μg·mL-1 and 10 μg·mL-1 Escherichia coli（E. coli） LPS after 6, 12, 24 and 48 h was detected by enzyme linked immunosorbent assay（ELISA）. The level of RANKL in HPDLFs stimulated by 1 μg·mL-1 E. coli LPS after pretreatment with different titre anti-TLR2+anti-TLR4, anti-TLR2 and anti-TLR4 antibody were observed respectively. Results RANKL was detected at 6 h after stimulation with LPS, and the levels of these cytokine were highest at 24 h, and then gradually decreased. The regularity of each LPS concentration was approximately similar. After pretreatment with anti-TLR2+anti-TLR4, anti-TLR2 and anti-TLR4 antibody, the level of RANKL was significantly decreased under the stimulation of 1 μg·mL-1 LPS（P<0.05）. In the three groups, the expression of RANKL was significantly different（P<0.05）. The level of RANKL in anti-TLR2+anti-TLR4 antibody pretreatment group was the lowest, the level in anti-TLR4 antibody pretreatment group was higher, and the level in anti-TLR2 antibody pretreatment group was the highest. Conclusion TLR2
and TLR4 participate in the process of RANKL expression in HPDLFs induced by LPS. Anti-TLR4 antibody has better inhibition effect to RANKL expression of HPDLFs stimulated by LPS than anti-TLR2.

Objective  The aim of this study was to analyze the initial displacement of the maxillary first molar by tip back bend in Tip-Edge force system and to explore the relationships between the displacement and the degree or position of tip back bend. Methods The Tip-Edge three-dimensional finite element model was constructed by CT scan of a dry skull with all teeth. The conditions of five types of degree（20°, 30°, 40°, 50°, 60°） and four types of position（2, 4, 6, 8 mm） of tip back bend were added to the three-dimensional finite element model and the initial displacements of the maxillary first molar were calculated. Results Under the effect of tip back bend, distal and extrusive displacement of the maxillary first molar occurred. The distal and extrusive movement increased as the degree of tip back bend increased or the position of tip back bend moved distally. Conclusion  The initial displacement of the maxillary first molar could be controlled by the precise control of the degree and position of tip back bend.

A mandibular fracture case of twice internal fixation surgery with poor healing was treated by denture prosthodontics in Affiliated Stomatological Hospital of Nanchang University. Th章福保（1987—），男，江西人，硕士e profile of maxillofacial region was improved, the masticatory function was enhanced, and the new bone formation was promoted.