Objective　　To explore the relationship between IhhPTHrP feedback pathway and the biological response to alteration of pressure microenvironment in the condylar chondrocytes.Methods　　The condylar chondrocytes from the temporomandibular joint of 4weekold New Zealand white rabbit were aseptically dissected and cultured in vitro.The monolayer of condylar chondrocytes was subjected to the static pressure of 100 kPa at different times (0 h,1 h,2 h,3 h and 4 h).Production of COL2A1,Ihh and PTHrP was examined by western blot and quantitative realtime PCR.The changes of condylar chondrocytes (100 kPa,3 h) morphology were analyzed by scanning electron microscope compared with the control group (100 kPa,0 h).Oneway ANOVA was performed using SPSS19.0 software package for statistical analysis.Results　　The western blot results showed that the exposure of chondrocytes to 100 kPa resulted in significant up regulation of COL2A1 after 3h.Increased expression of Ihh and PTHrP could be found in the condylar chondrocytes in respond to static pressure within 0～2h.Moreover,Ihh reduced in the condylar chondrocytes within 2～4h,whereas the expression of PTHrP maintained a high level after 2h′s treatment.The gene expression of Ihh and PTHrP was similar to the proteins.The result of scanning electron microscope showed that the process of the condylar chondrocytes prolonged after 3 hours treatment.Conclusions　　The condylar chondrocytes is good at adapting to the alteration of pressure microenvironment.It is sure that a suitable static pressure loading can accelerate chondrogenesis of condylar chondrocytes.IhhPTHrP feedback pathway is involved in the regulation of the alteration of pressure microenvironment in condylar chondrocytes.

Objective　In vitro assessment of the excellent osteoinductive ability of a self-sustaining graphene hydrogel on human adipose-derived stem cells (hADSCs).Methods　（1）The hADSCs were cultured on both SGH films and control glass, and cell adhesion and morphology were examined by scanning electron microscopy (SEM) and immunofluorescence analysis;（2）The in vitro experiments were divided into three groups, SGH films group, glass group (osteogenic medium) and control glass group (normal growth medium). In addition, in vitro experiments for osteogenic potential by hADSCs were performed for comparison among the three sample groups. Results　The hADSCs, as on control glass, also attached tightly on the surface of the SGH film and appeared normal cell morphology. The in vitro study showed better osteogenic differentiation of hADSCs on self-sustaining graphene hydrogel group scaffolds than in the control group（P<0.05）, due to the higher ALP activity, osteocalcin mRNA expression and mineralization, while its osteogenic ability was lower than in an osteogenic medium. Conclusion　This self-sustaining graphene hydrogel film appears to be highly biocompatible and osteoinductive for hADSCs.

Objective To investigate the condylar cartilage cell apoptosis in young rats with bilateral intermittent nasal obstruction to try exploring the influence of intermittent nasal obstruction on the development of condylar cartilage of children who have to breathe through mouth. Methods Twenty 4-week-old SD rats were employed and divided into two groups. Group A：10 of them had both nostrils occluded by nose plugs on normal oxygen conditions up to 8 hours for 35d and group B served as the control group：10 of them were raised under normal oxygen conditions. The same food and water were offered to the two groups and then the bilateral condylar was extracted to make parafin section for the immumohistochemical staining, including Caspase-3, Bcl-2, Bax protein. Cartilage cell proliferation and apoptosis, the regulatory mechanism of Bcl-2 gene family and its correlation with maxillary growth were observed and analyzed. Results Under the circumstance of bilateral intermittent nasal obstruction, the apoptosis of condylar chondrocytes in Group A increased significantly compared with the control group. The expression of caspase-3, bcl-2, bax protein was significantly higher than the control group. Conclusion Oral breathing caused by nasal obstruction results in the apoptosis in the condyle process cells

　Objective　To investigate whether titanium material could be used as transition disc during distraction osteogenesis. Methods　Unilateral mandible split was performed in 10 New Zealand white rabbits. Titanium membrane was inserted into the fracture site and covered one side surface. After 5 days’ delay, distraction was performed 0.8mm per day and twice a day. Total distraction length was 8 mm. After 16 weeks’fixation，the new bones were grafted and subjected to histological radiologic and pathological analysis. Results　Successful distractions were found in 3 of the rabbits. Some new bone formation could be detected in 2 of the rabbits. Conclusion　Titanium material might be used as the transition disc during osteogenesis distraction.

Objective To investigate the genetic characteristics of a family with congenital oligodontia and to find the possible disease-causing genes. Methods There were 3 generations, 17 members in all in this family. They accepted to cooperate and signed the informed consent form. The experimental protocol was approved by the Ethical Review Committee of School of Stomatology, China Medical University. Clinical examination was done for all the family members and panoramic radiograhs were taken. The peripheral blood samples were collected from the familial members. DNA samples were analyzed for genetic screening by gene chip technology. The methods of polymerase chain reaction (PCR) amplification and DNA sequencing were used to detect the mutation of suspected FGF20. Results This family with non-syndromic oligodontia was consecutive genetic in three generations without gender difference and the penetrance was 100%. It was diagnosed as an autosomal dominant inheritance; FGF20 might be the possible disease-causing gene from analyses of gene chip detection; but no mutation was found in FGF20 gene exons and exon-intron junctions as indicated by PCR. Conclusions The pathogenic mechanism of oligodontia is relatively complicated. It might be a polygenic disease which is regulated by multiple genes; gene chip technique has limitation in detecting the disease-causing gene of familial with congenital oligodontia.

Objective　 To evaluate the effect of partial superficial parotidectomy on benign parotid tumor of superficial lobe. Methods The literatures were retrieved with computers about partial superficial parotidectomy for benign parotid tumor of superficial lobe from MEDLINE, EMbase, Cochrane Library, CNKI, CMCI, VIP, CBM, WANGFANG database. The data extraction and quality assessment were analyzed by two reviewers independently using software RevMan5.1. Results 24 studies were included, there were 1111 cases in PSP group and 1095 cases in SP group. Meta analysis showed: PSP surgical procedures can reduce the operation time (MD = -28.55,95% CI :10.43-14 .78; P <0.00001), and reduce the incidence of temporary facial paralysis, Frey's syndrome, salivary fistula [(OR = 0.27,95% CI :0.20-0 .35; P <0.00001), (OR = 0.20,95% CI :0.13-0 .32; P <0.00001), (OR = 0.29,95% CI :0.15-0 .55; P = 0.0002)], and the difference was statistically significant. It can also reduce the incidence of permanent facial paralysis (OR = 0.34,95% CI :0.11-1 .05; P = 0.06), but the difference was not statistically significant. In terms of the recurrence rate, there was no statistically significant difference between the two groups (OR = 1.23,95% CI :0.54-2 .81; P = 0.62). Conclusion The operative time of PSP is shorter. PSP is effective in shortening the operation time, reducing the incidence of postoperative complications and its curative effect is reliable, thus it can be used as the treatment of choice for benign superficial lobe of parotid.

Objective To investigate the influence of new zirconia implant and surface modified method on the osseointegration to provide evidence for the development and application of the implant . Method Healthy adult New Zealand White male rabbits received two types of implant with identical geometry on the femur: sintered zironcia implant for NO.1,zirconia implant with 10% porous coating for NO.2. Each animal received two types of implant and then healed for three time periods （4,12,and 26 weeks）. At each healing time, a push-out test was performed to assess implants stability ,while scanning electron microscopy analysis（SEM）was performed to scan the bone-implant interface. Results Two independent samples t test analysis revealed that there were statistical differences between the two groups at each healing period(4 week t=103.345，P<0.001;12 week t=24.251，P<0.001;26 week t=20.854，P<0.001).Remarkable osseointegrationwas seen with sintered zironcia implant and 10% porous coating zironcia implant. Conclusion The new zirconia implant and surface modified method can enhance the osseointegration.

Objective　To measure the incisor root resorption quantitatively by CBCT in the treatment of gummy smile by using implant anchorage. Methods　The straight wire appliance technology was used for 11 cases. Mini-screw implants were inserted between the central and lateral incisors.100 g force was used for the intrusion of incisors. Treatment stopped and maintainence began when the gingival margin flushed with smile line. CBCT images of all patients were taken immediately before and after intrusion. The measurement of the root length was from the longest axis on the saggital plane. Results　Significant improvement of gummy smile was found in all cases, and the average decrease was 2.47±0.64mm.The intrusion of incisors was 2.81±0.62mm.CBCT showed that the resorption was more in central incisors than that in lateral incisors. Conclusions　Root resorption occurred in the treatment of gummy smile by using implant anchorage, and CBCT can measure root resorption quantitatively.

Objective To compare histological changes of diced costal cartilage autografts in the subcutaneous tissue of dorsum nasi in different time periods. Methods Fifteen New Zealand white rabbits aged 3 months were used for the study. The costal cartilage was finely diced into 1.0 mm×1.5 mm×1.5 mm cubes and placed in the subcutaneous tissue of dorsum nasi respectively. Five of the rabbits were respectively killed in the 2nd,4th and 6th month during post-operative period. The histological section of each specimen was prepared with hematoxylin-eosin and Masson trichrome staining and used to evaluate chondrocyte viability and the degree of ossification. Results There was not clear absorption of the diced costal cartilage grafts. Diced costal cartilage grafts were wrapped in the peripheral connective tissue. They integrated into a whole. The mean percentage of nucleated chondrocytes in the 2nd, 4th and 6th month during post-operative period accounted for 48.16, 50.41, 43.38 percent respectively of the total cartilage, and the differences were statistically significant(P<0.05). The mean percentages of subchondral ossifying tissue in the 2nd, 4th and 6th month were 32.72, 45.10, 48.94 percent, respectively, and the differences were statistically not significant(P>0.05). The mean visual assessment score concerning the metachromatism of cartilage matrix were 1.29,2.22 and 2.65 during these three stages, respectively, and the differences were statistically not significant(P>0.05). Conclusion Diced costal cartilage autografts can be wrapped in the peripheral connective tissue well and form a unified whole. It is relatively stable about the chondrocyte viability and the status of bone metaplasia in the diced costal cartilage grafts. There’s no obvious absorption

Objective　To compare the effects of extraction versus nonextraction orthodontic treatments on oropharyngeal airway volume in patients with skeletal classⅠmalocclusion. Methods　40 patients with skeletal classⅠmalocclusion were selected, including 20 with four premolars extracted (Extraction Group, ExtG) and 20 controls (Non-extraction Group, NExtG). They were screened for pretreatment (T0) and posttreatment (T1) cone beam computed tomography (CBCT) scans. Constructed lateral cephalograms (three skeletal and four dental variables) and oropharyngeal (OP) volumes were measured at T0 and T1. Paired sample t-tests were used to compare the mean changes from T0 to T1 in both ExtG and NExtG. Independent sample t-tests were used to evaluate the different effects of extraction versus non-extraction treatment on oropharyngeal airway volume. Results　Changes in CoA and CoGn from T0 to T1 were found to be significant in both groups (P＜0.01）. In the ExtG alone, significant differences in U1-FH、IMPA、U1-Na Perp and L1-Na Perp were also found at the end of the treatment (P＜0.01). Despite the observed changes, differences in OP volumes and minimal constricted axial areas from T0 to T1 were not significant between two groups（P＞0.05）. In the ExtG, the location of the minAx changed in 8 patients at T1, and the minAx of 6 patients changed in NExtG at T1. Conclusion　Extraction of four premolars with retraction of incisors does not affect OP airway volume in the orthodontic treatment of skeletal classⅠmalocclusion.

To investigate the treatment effects of individualized lingual appliance on adult patients with Angle Class Ⅱ malocclusion. Methods 6 adult patients with Angle Class Ⅱ malocclusion in permanent dentition cases were chosen and treated with individualized bracket system in lingual appliance. Cephalometric analysis before and after treatment were performed. The changes of soft and hard tissue were recorded and analyzed. Results The manifestation of hard tissue change was mainly the decrease of the upper incisor labial inclination while that of soft tissue change was the increase of Cm-Sn-Ls angle and SnLs-SiLi angle. The profile of soft and hard tissue has improved distinctly .Conclusions The application of individualized bracket system in lingual appliance in treating angle class Ⅱ malocclusion of adult patients can also obtain good correction results.

Objective To compare the difference in color reappearance of bilayered and monolithic molar crown fabricated with four different kinds of Dental ceramics materials. Methods Bilayered and monolithic molar crowns were fabricated with four different kinds of Dental ceramics materials for 3 different patients: IPS E. max Press, VITA in-ceram YZ zirconia, Cercon HT zirconia, Upcera ST zirconia. Color parameters of the crowns were measured with Vita Easyshade Spectrophotometer，and the color difference( △E) of crowns and contralateral teeth was calculated．The effect of color reappearance of crowns was assessed by ten color Trained examiners. Results The layers of all-ceramic restoration exhibited no influence on the mean values of L* ，a* and b* ; the kind of all-ceramic Material exhibited significant influence on the values of a* and b* ( P ＜ 0. 001) ; the interaction of layers and kinds of all-ceramic Materials showed influence on the values of a* ( P =0.040) . In terms of the visual estimation results, the monolithic crowns fabricated with VITA in-ceram zirconia, Cercon HT zirconia were not receivable while the others were. Conclusions The four studied all-ceramic bilayered crowns could achieve acceptable aesthetics ;the monolithic molar crowns fabricated with IPS E. max Press, Upcera ST zirconia could achieve acceptable aesthetics while the monolithic crowns fabricated with VITA in-ceram YZ zirconia, Cercon HT zirconia couldn’t. The clinical selection of restorative materials must be based on the transparency of all-ceramic materials and natural teeth, the distribution of color, the balance for color and intensity. On the condition that the teeth is of low opacity with monotonous color and supports the heavy loading, the monolithic restorations could be considered.

To observe the influence of fluoride on the permeability and the bleaching effect of such bleach as Carbamide peroxide; to evaluate whether the use of 2 percent sodium fluoride before bleaching would decrease bleaching efficacy of HPCP when compared with a placebo and to confirm the applicability and reliability of the fluoride in clinic. Methods The crowns of 36 caries and developmental defect free human maxillary incisors were stained internally with a standard tea solution and colorimetric analysis was done with VITA shade guide. 12 specimens were bleached with light activated 35% hydrogen peroxide and another 12 were bleached by the same agents after using 2%NaF. 12 others were placed in ionized water (control group). The exposure time was all 30 mins. Vita shade guide [SG] was employed before, after tea staining and after power bleaching/water treatments. Eighteen specimens from three groups were sectioned mesio-distally. An additional 18 specimens from the bleach and the control group were sectioned labio-palatally. The stain area for each specimen was measured and compared with image analysis software. Results There was no significant difference in the change of color gradation after bleaching between two groups and there was no significant difference in bleaching depth of dentine between the bleaching group and NaF bleaching group. With tea staining, the mean changes in Vita shade guide units (SGU) ranged from 3.66 to 8.33. Samples bleached and sectioned mesio-distally showed stain coverage of 28.6– 39.4%, while palatal sections showed stain coverage of 58–72%. Control samples, whether sectioned mesio-distally or labio-palatally, showed staining throughout the dentine (97–100% coverage).Conclusion The use of fluoride partly before bleaching does not have influence on bleaching effect or depth.

Abstract Objective To elucidate the demand of pregnant women for the knowledge of oral health and dental care .Method A cross-sectional survey was carried out in three main women’s hospitals in Hangzhou, viz., 1) Women’s Hospital, Medical College, Zhejiang University; 2) Center for Disease Prevention and Control & Women and Children’s Healthcare of Gongshu District; 3) Center for Women and Children’s Healthcare of Jiang’an District from December 2010 to May 2011. The chi-square test was used to analyze the results. Results Within the six months, we distributed 2,500 questionnaires and received 2,263. 89.8% of the respondents thought it necessary to introduce the knowledge of prenatal oral care during pregnancy, and 92.4% of the respondents felt the necessity of introducing the knowledge of infant oral care during pregnancy. The demand for the knowledge related to the newborn and maternity was significantly correlated with their age, education and household income (p<0.05). But the demand for participating in the training of oral health knowledge was not significantly correlated with age, education and annual household income (p>0.05). The findings showed that the majority of the pregnant women hoped to obtain the knowledge directly through dental professionals. Maternal schools and brochures are relatively easier to be accepted by the pregnant women. Conclusions We can establish a number of pertinent educational programs for pregnant women for education and guidance in more suitable places.

Objective To discuss the effect of different mandibular arch widths and lengths on uprightness distortion ratio of the mandibular posterior area in digital pantomography with cone beam CT (CBCT) as the reference. Methods 150 cases of patients with pantomography and CBCT were selected. The mesial and distal alveolar bone heights between adjacent teeth in mandibular posterior area were both measured, and the results were analyzed. Results Compared with CBCT,in digital pantomography, the uprightness distortion ratio of the mandibular molar area was (3.85+2.03)%,while that of the premolar area was (4.78+2.15)%. When the arch width was 40.3-42.5 mm and the length was 20.5-23.4 mm, the distortion ratio was in its minimum, and the ratio was (1.95+0.13)% in molar area and (2.88+0.25)% in premolar area. Conclusion The width and length of mandibular arch are important factors affecting uprightness distortion ratio in the digital pantomography.

Objective To investigate the prevalence of crossbite in primary dentition in children located in Changning District of Shanghai. Methods A survey of crossbite was performed in 1750 children aged from three to five years old according to the criteria for normalbite. Results Crossbite prevalence rate in primary dentition of children was 12.46% in this district. There was significant difference between boys and girls at five, while there was no significant difference between boys and girls at 3 or 4, and among all age groups. Conclusions Crossbite in primary dentition is a common oral disease. More attention should be addressed in examination, prevention and treatment.