There are two ways to place dental implants in the maxillary posterior without sufficient bone available, one is the maxillary sinus floor bone augmentation technique, the other is to evade maxillary sinus. The maxillary sinus floor bone augmentation technique may result in a series of complication, and reduce obedience of patients for implant surgery. According to principles of the best bone utilization, the evaded maxillary sinus implant technique is more simple, more economic, more predictable, and more shortage of time, compared with the maxillary sinus floor bone augmentation technique, and has certain technological advantages in some special cases.

Objective To compare the influence of polishing and glazing on ceramic surface roughness and bacterial adhesion to the resulted surfaces. Methods The surface of the ceramic plates were tested and analyzed by atomic force microscope. The influence of resulted surface on Streptococcus mutans adhesion were also evaluated. Results The ceramic surface became much smoother after polishing with diamond paste or self-glazing. A positive correlation between surface roughness and bacterial adhesion were observed. Compared with surfaces polished with rubber-wheel, surfaces polished with diamond paste or self-glazing reduced bacterial adhesion to the surface（P<0.05）. Conclusion Polishing with diamond paste could be an alternative to self-glazing on ceramic surface roughness and bacterial adhesion.

Objective To investigate the chemotactic response of human periodontal ligament stem cells（PDLSCs）to bone morphogenetic protein-2（BMP-2）. Methods Human PDLSCs were obtained from clinically healthy premolars extracted for orthodontic reasons and used to isolate PDLSCs by limited dilution method. The expression of Vimentin and stem cell marker STRO-1 on PDLSCs were demonstrated with immunocytochemical staining. Differentiation assay was used to detect the differentiation potential of PDLSCs. Cloning formation experiment and 5-bromo-2-deoxyuridine （BrdU） incorporation assay were used to determine the stem cell characteristics of PDLSCs. The chemotactic effect of BMP-2 on PDLSCs was detected by using a 24-multiwell Transwell cell culture chamber. The number of net migrated cells was counted in different microscope fields. Results Human PDLSCs displayed positive staining for Vimentin and expressed the stem cell marker STRO-1. These cells differentiated into osteoblasts and adipocytes under defined culture conditions, possessed high self-renewal potential and formed single-cell colonies in vitro. The number of cells migrating at concentrations of 100, 200 ng·mL-1 of BMP-2 in Transwell cell culture chamber was significantly higher than that of negative control （P<0.01）. Conclusion BMP-2 may participate in regulating chemotaxis of human PDLSCs.

Objective To study the changes in surface morphology of cobalt-chromium alloy, pure titanium and high-cobalt chromium molybdenum alloy immersed in artificial saliva with different concentrations of fluoride, and to analyze the corrosion resistance of these metals. Methods The three kinds of metal were polished and then were immersed in artificial saliva with different concentrations of fluoride（0%, 0.05%, 0.2%）. All specimens were immersed for 3 weeks at（37.0±1.0）℃. Metal surface roughness before and after immersion were measured and analyzed by scanning electron microscope（SEM）. Results Metal surface roughness was increased with the concentration of fluoride. The surface roughness of the Co-Cr group and Ti group had a statistically significant difference between before and after immersion at the fluoride concentration of 0.05%（P<0.01）, and the difference between Co-Cr group and vitallium2000 group, Ti group and vitallium2000 group were statistically significant difference（P<0.01）. The differences of three groups before and after immersion were statistically significant at the fluoride concentration of 0.2%（P<0.01）, and the difference among three groups was statistically significant（P <0.01）. Conclusion Patients who frequently use fluoride products should not use pure titanium or cobalt-chromium alloy prosthesis. Patients with these three metal prostheses are not advised to use high concentration fluoride products.

Objective To evaluate the effect of erythritol on cell wall structure of Streptococcus mutans（S.mutans） and explore its potential mechanism. Methods Enzyme activities of lactate dehydrogenase（LDH） in bacterial solution were detected under respective condition of sucrose and erythritol. A scanning electron microscope（SEM） was used to investigate the change of S.mutans’cell wall under the condition of sucrose and erythritol. Results Enzyme activities of LDH in erythritol culture medium were different from that in sucrose, but the difference was slight. SEM observation showed the integrity of cell wall was not destroyed and no content leaked out. Conclusion It’s suggested that erythritol has an antibacterial effect on S.mutans through no affecting on the normal structure of the cell wall of S.mutans.

Objective To study mRNA expression of receptor activator nuclear factor kappa B ligand（RANKL） and its decoy receptor, osteoprotegerin（OPG） in peri-implant tissue during unloading period. Methods An animal model of dental implant was established in 6 male Beagle dogs of 1-2 years old. Bone remodeling was tested at 3, 7, 15, 30, 60 and 90 days since the placement of implants. RANKL and OPG mRNA expression were quantified by real-time polymerase chain reaction（PCR）. Then mandibular bones were taken out and the morphological changes were observed by X-ray, bone tissue was tested by immunohistochemistry stain. Results The most prominent period of bone remodeling occurred at 7th day after the placement of implants. The expression of RANKL and OPG increased in a timedependent manner in both soft and hard tissue. After 7 days they gradually decreased. Conclusion RANKL and OPG can express in soft tissue, and the changing tendency is consistent with the change of bone remodeling, it indicates that RANKL and OPG play an important role in the bone remodeling.

Objective This in vitro study is to evaluate the effect of ultrasonic power settings and cooling methods on fracture behavior of the separated nickel titanium instruments during ultrasonic removal. Methods 40 discarded and 10 new nickel titanium instruments were used to establish the separated instrument removal model. The discarded instruments were divided into four groups according to two ultrasonic power settings（6 or 10） and different cooling methods（using water coolant or without using water coolant）, and all the new instruments were put into the group in which ultrasonic vibration was used at a higher power setting（10） without using water coolant. The time required for fracture of the separated instruments was recorded. Results The time was longer with statistical significance at a lower power setting compared with that at a higher power setting regardless of the use of water coolant. The time was longer with statistical significance by the use of water coolant compared with that without using coolant regardless of power settings（6 or 10）. The time required for fracture of the new instruments was longer than that of the discarded instruments with statistical significance. Conclusion During ultrasonic removal of separated nickel titanium instruments, water coolant could decrease the occurrence of fracture. When removing separated nickel titanium instruments with ultrasonic vibration, an attempt without coolant shouldn’t be made at a higher power setting.

Objective To investigate the effect on natural killer（NK） and cytotoxic T lymphocyte（CTL）-mediated cytotoxicity by genetic overexpression of MHC class Ⅰ chain-related protein A（MICA） in oral squamous cell carcinoma （OSCC）. Methods The OSCC cells by genetic overexpression of MICA were detected to identify the biological features including cell growth curve, cell cycle distribution, plate clone forming rate and tumorigenicity in nude mice. The expression of natural killer group 2, member D（NKG2D） receptor and the cytotoxicity to target tumor cells of NK92 and CTL cells, which co-cultured with the transfected OSCC cells or the non-transfected or blank vector-transfected controls, were measured by flow cytometry and lactate dehydrogenase（LDH） release assay. Results There was no difference in biological features before and after MICA gene transfection to OSCC cells. Flow cytometry and LDH release assay showed that MICA-overexpressed OSCC cells enhanced the cytotoxicity to target tumor cells and up-regulated the expression of NKG2D on NK92 and CTL（P<0.05）. Conclusion MICA may be considered as a promising immunotherapy target of OSCC.

Objective To evaluate the accuracy of positron emission tomography（PET）/computed tomography（CT） for detecting cervical nodule metastases of oral and maxillofacial cancer. Methods Diagnostic test accuracy studies assessing the accuracy of PET/CT in diagnosis of cervical metastases of oral and maxillofacial cancer were retrieved from the databases of CBM, Medline（OVID） and EMBASE（searched on Dec. 13th, 2010） and manual searching of 19 dental journals in Chinese. Two researchers were employed in the articles investigation independently and evaluated the quality with quality assessment of diagnostic accuracy studies（QUADAS）. Meta-analysis was done using MetaDisc 1.4. Results Nine studies met the inclusion criteria and demonstrated high methodological quality. The results of Meta-analysis showed that, when nodal level was used as unit, PET/CT had good diagnostic value in detecting the cervical nodule metastases of oral and maxillofacial cancer. Under such a condition, the pooled sensitivity was 0.84, pooled specificity 0.93, pooled diagnostic odds ratio 47.89 and area under the curve 0.973 8. Conclusion The accuracy of PET/CT for detecting cervical nodule metastases of oral and maxillofacial cancer is relatively high and it could be used as a good diagnostic tool. And special attention should be payed to its diagnostic expense and safety when considering PET/CT.

Objective To investigate the oral health-related quality of life in patients with oral lichen planus（OLP） using the Chinese version of the oral health impact profile（OHIP）-14. Methods 51 patients with OLP were included and completed the questionnaire of OHIP-14 subsequently the REU scoring system was utilized to record the local condition and a visual analogue scale（VAS） to rate the pain they experienced. The reliability and validity were analyzed by SPSS 16.0 software. Results The score of OHIP-14 was 21.67±9.45, Cronbach’s alpha of the translated scale was 0.901. The items were divided into 5 domains by factor analysis. There was certain logical relation between the items in the same domain. There was highly significant association between the OHIP-14 score and REU score as well as VAS score（r=0.608, 0.807, P<0.000）. Conclusion OHIP-14 performs well in patients with OLP, and have good validity and reliability.

Objective To analyze the effects on the morphology of temporomandibular joint（TMJ） of the adult with the low angle Class Ⅱ malocclusions before and after orthodontic treatment comparatively. To provide the references for the orthodontic treatment of the adults. Methods 19 adult patients with low angle Class Ⅱ malocclusions were chosen and treated with Damon self-ligating braces. The examinations of 16-slice spiral CT were taken before and after the orthodontic treatment. The parameters of skeletal morphology of TMJ were measured in the multiplanar reconstruction（MPR） images. The results were analysed statistically. Results The rate of condyles in a center position in the glenoid fossa after the treatment was 52.6%（20/38）, and the rate of retrodisplacement was 31.6%（12/38）. The position of the condyles before and after the orthodontic treatment had significant differences（P<0.05, 掊2=4.41, 掊2=5.32）. The mean value of the anterior oblique angle of condyle decreased by 2.32°±1.78° after treatment, meanwhile the average height of the condylar head increased by（1.07±0.29）mm. There were significant differences in both results before and after treatment（P<0.05）. Conclusion The orthodontic treatment can make the TMJ structures stable and beneficial to relieve the symptoms by moving the condyle forward, increasing the height and reconstructing the anterior oblique angle of condyle on adult patients with low angle Class Ⅱ malocclusions.

Objective To evaluate the effects of angle Class Ⅱ division 2 malocclusion treated with Herbst appliance in young adults. Methods Cast splint Herbst appliance and multi-bracket appliance were used to treat 12 patients with Class Ⅱ division 2 malocclusion aged from 16 to 25 years old. The lateral cephalograms were measured with Winceph 8.0 software and statistical analysis was carried out by SPSS 13.0 software. Results The changes in SNA, Co- Go, Go-Po after treatment had no statistical significance（P>0.05）. The SNB increased and ANB decreased after treatment. Upper and lower incisors labially inclined and inter-incisor angle increased. Upper posterior teeth had distal movement, lower posterior teeth had mesial movement and extrusion. Mandibular plane angle and occlusal plane angle had clockwise rotation. The overbite decreased significantly, and the molar relationship changed from Class Ⅱ to Class Ⅰ in all patients. Conclusion Herbst appliance combined with multi-bracket appliance can be used effectively for correcting Class Ⅱ division 2 malocclusion in young adults.

Objective To study the short-term effects of nociceptive trigeminal inhibitory tension suppression system（NTI-tss） and occlusal stabilization splint（OS） on sleep bruxism patients. Methods Ten patients received the two splint treatments in a randomized cross-over fashion：An NTI-tss and an OS for a 1-week period, respectively. Record the bruxism episodes per hour, micro-arousals per hour of the patients before wearing the splints（baseline）, the first night and 1 week after wearing the splints with polysomnography. Statistical analysis was performed with SAS 9.1 by means of mixed effect model analysis. Results There were no differences among the micro-arousal index of the baseline, the first night and 1 week later with both types of the splints（P>0.05）. The NTI-tss was associated with a significant reduction in bruxism index compared with baseline. The bruxism index of baseline, the first night and 1 week later were 7.50±1.11, 3.45±1.22, and 3.51±1.03 per hour（the first night vs baseline, t=26.52, P<0.01; 1 week vs baseline, t=26.12, P<0.01）. There were also significant differences in the bruxism index after wearing the OS. The bruxism index of baseline, the first night and 1 week later were 7.44±1.23, 2.97±0.91 and 6.43±1.02 per hour（the first night vs baseline, t=16.79, P<0.01; 1 week vs baseline, t=3.79, P<0.01）. Compared with the NTI-tss group, the reduction was much less, especially 1 week later. Conclusion Both the NTI-tss and the OS splints can reduce the bruxism index, and have no affect the incidence of micro-arousal. In this short term study, the NTI-tss was more effective than the OS for
the treatment of sleep bruxism.

Objective To compare the consistency of root canal configuration types of mandibular first premolar by using micro-CT and radio visio graphy（RVG）. Methods One hundred extracted mandibular first premolars with complete dental root and apex which received no endodontic treatment were randomly selected. Each tooth was radiographed with RVG through a buccolingual and mesiodistal direction, and then scanned with micro-CT and reconstructed. The classifications of the root canal types according to Vertucci’s type with the two methods were compared. Results The canal patterns were classified as type Ⅰ（67%）, type Ⅲ（3%）, type Ⅴ（18%）, type Ⅶ（2%）, additional type（10%） with micro-CT and canal patterns as type Ⅰ（71%）, type Ⅲ（2%）, type Ⅴ（23%）, type Ⅶ（1%）, additional type（3%） with RVG. 63% of teeth showed one canal in both micro-CT and RVG. Only 25% of teeth were diagnosed  as complex canal by the same canal type in both micro-CT and RVG. The Kappa value between micro-CT and RVG was 0.541 which suggested that the two kinds of methods had intermediate consistency. 82.8% of the premolars with root groove had two or more than two canals. Conclusion Although RVG can basically reflect the root canal system type of the mandibular first premolars in vitro, it offers poor accuracy images to complex root canals. Micro-CT threedimensional images could clearly and precisely display the root canal system morphology of the mandibular first premolars in vitro.

Objective To assess the two-year outcome of initial endodontic treatment and evaluate the relationship between the treatment outcome and relevant factors. Methods A total of 296 patients with 371 teeth received initial endodontic treatment between January 2005 and December 2007 were included in the study. The teeth were treated using crown down technique, and followed for two years. The outcome was examined clinically and radiographically. The relevant factors, including pulp vitality, apical periodontitis, the number of tooth root, and state of root canal obturation, were analyzed. Results 143（176 teeth） from 296 patients（371 teeth） were followed for two years. 152 teeth （86.36%） with normal limits were assessed as“healed”（no apical periodontitis, no signs or symptoms）. 24 teeth were assessed as “disease”, 12 teeth were extracted and 12 teeth were retreated. The healing rate（HR） was statistically higher for vital teeth（95.38%） than that for devital teeth（81.08%）. The HR of teeth without apical periodontitis（95.24%） was significantly higher than that with apical periodontitis（73.24%）. Other factors were associated with different HR, but no statistical significance（P>0.05）. Conclusion Apical periodontitis and pulp vitality may be prognostic factors for outcome of initial endodontic treatment.

Objective To detect the ability of Enterococcus faecalis（E.faecalis） biofilm formation and explore the relationship between E.faecalis biofilm formation ability and clinical manifestation. Methods 96 well plate with the establishment of 53 E.faecalis in vitro biofilm model, combined with crystal violet staining, was used to test the biofilm formation ability of the clinical isolates E.faecalis and analyze the relationship between biofilm formation capacity and clinical manifestation. Results In total 53 E.faecalis strains, 40 strains（75.47%） had biofilm forming ability. Statistical analysis revealed that the capacities of biofilm formation between E.faecalis isolated from with fistula and without fistula was significantly different（P<0.05）. Conclusion In the retreatment of root canal, the ability of biofilm formation of E.faecalis separated from the teeth without fistula is better than those separated from the teeth with fistula.

Objective To evaluate facial morphology characteristics of patients with unilateral complete cleft lip and palate（UCCLP） after cleft palate repair in different periods. Methods 46 nonsyndromic UCCLP patients were chosen as test group and divided into three kinds（under 4-year-old, 4-7-year-old, over 7-year-old） according to periods of palate repair. 38 age and gender matched non-clefts children were involved as control group. 26 cephalometric measurements were measured to evaluate facial morphology of four groups. Results Compared with patients who received palate repair before 4-year-old, patients who received repair after 4-year-old had more protrusive ANS point（Ba-NANS, Ba-ANS） and less Y-axis angle. Patients who received palate repair after 7-yesr-old had greater A-PMP and ANS-PMP than patients who received palate repair before 4-year-old, patients who received palate repair before 7- year-old had smaller ANS-Me but after had no significant difference when compared with non-clefts. Conclusion Whenever palate repair is undertaken in the period of maxillary growth and development, patients’maxillary growth would be restrained, the delayed repair sample have better lower face height, maxillary protrusion, maxillary sagittal length and mandible growing direction when compared with the early repair sample, that is to say, the delayed repair sample have preferable head-face morphology.

Objective To evaluate the influence of mechanical property of tooth-like yttria-stabilized tetragonal zirconia polycrystal（Y-TZP） by adding rare earth oxide as colorants. Methods Six kinds of tooth-like Y-TZP were made by introducing internal coloration technology. The colorants included rare earth oxide（Pr6O11, CeO2, Er2O3） and transition element oxide（MnO2 ） . Mechanical properties（flexural strength, vickers hardness and fracture toughness） were tested. Microstructure was examined by scanning electron microscope（SEM）, and the fracture model was analyzed. Results The range of flexural strength of the six kinds of tooth-like Y-TZP were（792±20）-（960±17）MPa, the fracture toughness were（4.72±0.31）-（5.64±0.38）MPam1/2, and the vickers hardness were（1 332±19）-（1 380±17）MPa. SEM observation on the cross section of the six kinds of sintered composites showed a relatively dense polycrystal structure, and the fracture models was mixed type. Conclusion Tooth-like Y-TZP is acquired with better mechanical properties（fracture toughness and vickers hardness） by adding rare earth oxide as colorants. It is available for clinical application.

Objective To explore the expression of Toll like receptor 4（TLR4） on the pulp cells and the change of related signaling molecules under the condition of concomitant lipopolysaccharide（LPS） and transforming growth factor-β1（TGF-β1） during the course of pulpitis. Methods After treated by LPS and TGF-β1, the expression of TLR4 on pulp cells was detected by flow cytometry（FCM）. The expressions of signaling molecules evolutionarily conserved signaling intermediate in Toll pathways（ECSIT） and nuclear factor-κB（NF-κB）were detected by real-time polymerase chain reaction（real-time PCR） and Western blot. The secretion of interleukin-6（IL-6） was detected by enzymelinked immunosorbent assay（ELISA）. Furthermore, the change of corresponding targets in inflamed pulp cells from clinical samples were detected by real-time PCR. Results After treated by LPS and TGF-β1 in vitro, there was no change in the expression of TLR4 on pulp cells, but the secretion of proinflammatory cytokines IL-6 increased. LPS and TGF-β1 could also increase the expression of signal downstream ECSIT and actived NF-κB. Furthermore, the expression of TLR4 mRNA had no increase in inflamed pulp cells from clinical samples, while the expression of TGF- β1, ECSIT and IL-6 mRNA increased through real-time PCR. Conclusion During the course of pulpitis, although the expression of TLR4 on pulp cells was inhibited by increased expression of TGF-β1, the TLR4 pathway was still activated. This effect could be caused through activation of ECSIT mediated by LPS, which might inhibit the TGF- β1 pathway.

Objective The aim of this study is to optimize conditions for labeling human periodontal ligament stem cells（PDLSCs） using enhanced green fluorescent protein（eGFP） infected by lentivirus vector and to obtain PDLSCs with high stable expressed eGFP． Methods PDLSCs were transfected with eGFP by lentivirus vector for 48 h via different multiplicity of infection（MOI）（25, 50, 100, 200 and 400） and the infection efficiency were analyzed by both fluorescent microscope and flow cytometry. The proliferation rate of infected PDLSCs was evaluated by MTT. The infected PDLSCs were further for detection of pluripotent, differentiation ability and alkaline phosphatase（ALP） expression ability. Results The infection efficiency for each group were 44.7%, 60.9%, 71.7%, 85.8% and 86.9% respectively. Proliferation of PDLSCs was not affected when MOI was below 200; however, at MOI 400, the proliferation ability was affected compared with control group. The pluripotent and ALP abilities of PDLSCs were not changed by the infection. Conclusion Infection for 48 h at MOI 200 is optimal for labeling PDLSCs with eGFP using lentivirus vector, and the proliferation and differentiation abilities of PDLSCs are not affected obviously.

Objective To study the effects of Lactobacillus acidophilus（L.acidophilus） on the proliferation and cell  cycle distribution of human tongue cancer cells（Tca8113 cells）. Methods In vitro cultivated human Tca8113 cells were treated by L.acidophilus supernatant, inactivated bacilli, cell free extracts and normal culture medium respectively, which were 1, 4, 16-fold（s） dilutelly, to investigate the proliferous effects of Tca8113 cells using of inverted microscope, cell counting, sulforhodamine B（SRB） and flow cytometry. The free radicals and Ca2+ in Tca8113 cells were also studied by confocal laser scanning microscope（CLSM）. Results At the 48th hour after adding different L. acidophilus components, the Tca8113 cells changed in shape from the diamond-like, polygonal and slabs into the elongated form. In the condition of different times and different culture concentrations, the proliferation of Tca8113 cells was significantly inhibited by L.acidophilus components, which enhanced as the time prolonged and the concentrations of each L. acidophilus components increased according to the cell counting and the SRB experimental analysis. The cell proliferation index（CPI） was significantly reduced（P<0.01）. The free radicals and Ca2+ in Tca8113 cells under the effect of each L. acidophilus components for 48 h indicated an obviously rising（P<0.01）. Conclusion L. acidophilus restrains the proliferation of Tca8113 cells, which might be due to the increase in quantity of free radicals and Ca2+ in Tca8113 cells, and might be resulted from the release of metabolic products of L.acidophilus.

Objective To investigate the expression of Toll like receptor 2（TLR2） and interleukin-1β（IL-1β） of cultured human periodontal ligament cells（HPDLCs） activated by Enterococcus faecalis（E.faecalis） lipoteichoic acid （LTA）. Methods HPDLCs that were obtained from the periodontal tissues of healthy humans were maintained in proper condition. Flow cytometry was used to detect the expression of TLR2 on normal HPDLCs and infectious HPDLCs which were incubated with 0.1, 1, 10 μg·mL-1 E.faecalis LTA for 24 h. IL-1β was detected by enzyme linked immunosorbent assay（ELISA） after incubating with LTA of the above concentration for 12, 24 and 48 h or pretreated with TLR2 neutralizing antibody for 1 h and then co-cultured with 1 μg·mL-1 LTA for 24 h. Results E.faecalis LTA promoted the expression of TLR2 in normal HPDLCs. The difference had statistical significance（P<0.05）. IL-1β secretion could be detected 12 h after stimulation with LTA and increasingly escalate within 48 h（P<0.05）. TLR2 neutralizing antibody had no evident effect on IL-1β generation stimulating by E.faecalis LTA. Conclusion E.faecalis LTA can increase the expression of TLR2 and IL-1β in normal HPDLCs.

Objective To investigate the association between small ubiquitin-related modifier-1（SUMO-1） gene rs6709162, rs7599810, rs7580433 polymorphism and non-syndromic oral clefting（NSOC）. Methods Our study consisted of 208 Ningxia NSOC patients, their parents（189 fathers and 176 mothers）, 172 nuclear families（patients and their parents）, and 284 normal controls. DNA was extracted and polymerase chain reaction-restriction fragment length polymorphisms（ PCR-RFLP） was used to identify rs6709162, rs7599810, rs7580433 genotypes of the samples. The data was analyzed by case -control analysis, family based associated test（FBAT）, and transmission disequilibrium test（TDT）. Results Case-control study found that TT genotype’s frequency was significantly different in cleft lip and cleft palate group compared with the control group at rs7599810 of SUMO-1（P=0.01, P=0.01）. TDT test showed that rs7599810’s T allele had over-transmitted（P=0.00） in cleft lip and palate group. FBAT analysis revealed that distribution of rs75- 99810’s TT genotype and T allele was significantly different（P=0.00, P=0.00）. TDT test showed that rs6709162’s C allele in cleft palate and cleft lip and palate patients had over-transmitted（P=0.00, P=0.01）. rs7580433’s G allele in cleft lip group had over-transmitted（P=0.05）. Conclusion SUMO-1 gene polymorphism is associated with NSOC.

Block anesthesia of inferior alveolar nerve is commonly used in oral clinic service, but aphonia is rare. A case of aphonia induced by block anesthesia of inferior alveolar nerve was reported and the relevant literatures were reviewed.

Submandibular ectopic thymus is rare in clinical. As this lesion is usually asymptomatic, it easily leads to misdiagnosis and treatment failure. This article reported a case of submandibular mass caused by ectopic thymus, and discussed based on relevant literatures.

Diseases of oral mucosa are characterized by complex etiology, diverse and confused clinical manifestations, as well as lack of special therapeutic drugs and methods. So it has always been a non-evasive teaching conundrum. This paper explored a multiple three-dimensional interactive teaching mode, a combination of problem-based learning（PBL）, case-based learning（CBL）, multimedia, internet and evidence-based medicine. It is hoped that its application in the teaching of the diseases of oral mucosa will arouse the students’learning interest, broaden their professional perspective, cultivate their self-learning ability to find, ask, analyze and solve problems, and strengthen their clinical practice capacity.