Objective:To evaluate the changes in the transverse dimension and the perimeters of the maxillary archs produced by 3 self-ligating appliance systems during the leveling and aligning phases. Methods: 45 patients who had class I skeletal pattern and upper arch crowding 3-6 mm were divided into 3 groups with 15 subjects in every group. The dental casts were analyzed. Results: Statistically significant increases were recorded of all dentoalveolar widths (with the exception of intermolar width measured lingually) and arch perimeters. The increase in arch perimeter showed a significant negative relationship with the individual perimeter of the maxillary arch before treatment. No significant change was found in arch depth. Conclusion: The self-ligating appliance systems produce statistically significant increases in the transverse dentoalveolar width and the perimeter of the maxillary arch during the leveling and aligning phases of treatment.

Objective:To assess the effect and mechanism of ClassⅢ malocclusions treatment with Frankel-Ⅲ appliance and reverse Twin-block appliance. Methods:Twenty subjects of ClassⅢ malocclusion were included in this study(9 males,11 females). Among them, 10 subjects were randomly selected for treatment with reverse Twin-block appliance (T group) and 10 subjects for Frankel-Ⅲ appliance (F group). All patients were treated all the day for total of 4-11 months. The cephalometric records of these subjects were examined before and after treatment. The acquired data were processed with SPSS 10.0. Results: The results showed a mandible receded backward in both groups. Both group could accelerate the development of the maxillary bone. But the Frankel-Ⅲ was more effective. F group had significant effects of uprighting upper frontal teeth and flaring lower teeth. the average treatment time was 6.5 months in reverse twin-block appliance therapy group and 9 months in Frankel-Ⅲ appliance group. Conclusion: Both reverse Twin-block appliance and Frankel-Ⅲ appliance can treat angle classⅢ malocclusions effectively. The effects of maxillary changes of Frankel-Ⅲ appliance is better than reverse Twin-Block. Treatment period is shorter in T group than in F group.

Objective:To analyze the value of fine needle aspiration cytology and CT perfusion imaging in differential diagnosis of benign and malignant salivary gland tumors. Methods: Perfusion CT and fine needle aspiration cytology were performed in 36 patients of salivary gland tumors(26 cases in parotid gland, 8 cases in submandibular, 1 case in sublingual gland and 1 case in pars palatalis) and perfusion parameters, including: blood flow(BF), blood volume(BV), mean transit time(MTT), permeability surface(PS). Pathological diagnosis was performed on all salivary gland tumors. Results: 13 cases of 36 patients eventually were diagnosed as malignant salivary gland tumors. The sensitivity, specificity and accordance rate for malignancy of fine needle aspiration cytology were 84.6%(11/13), 95.7%(22/23) and 91.7%(33/36), respectively. The values of BF, BV and PS of the malignant tumors were higher than those of benign tumors significantly(P<0.05). However, the MTT values showed no significant difference between benign and malignant tumors(P>0.05).The sensitivity, specificity, and accordance rate for malignancy of CT perfusion were 92.3%(12/13), 86.9%(20/23) and 88.9%(32/36), respectively. The negative cases of fine needle aspiration cytology can be correctly identified as malignant by CT perfusion imaging. Conclusion: CT perfusion imaging can provide salivary gland tumors with information of microcirculation perfusion. It contributes to the identification of benign and malignant tumors. Paralled with fine needle aspiration cytology can greatly improve the accuracy of salivary gland tumors.

Objective:To study the association between the rs2013162 and rs2235375 polymorphisms in IRF6 and risk of NSCL/P in west Chinese population. Methods: The study group consisted of 332 NSCL/P patients, their parents (289 mothers, 243 fathers and 206 complete families), and 174 controls. PCR-RFLP method was used to identify genotypes and both case-parent and case-control designs were carried out on samples from west China. Results: There were significant differences in the frequency distributions of both genotypes and alleles when cases were compared with control infants at the rs2235375(P<0.01, P<0.01 respectively). We found strong evidence of over-transmission of the G allele at rs2235375 in cleft case-parent trios(P<0.01). Five specific haplotypes showed significant over-and under-transmission. Conclusion: These results suggest IRF6 variants play a role in NSCL/P in west Chinese populations.

Objective:To identify the normal position of the root tips of lower premolars, first and second molars, the distances through 3-D reconstruction in 100 cases of general population were measured. Methods: The three distances were measured from 100 cases over 17 years old, divided by gender: 1. The distance of Mandible of the Centre (M) under the jaw to the lower edge of the next point (L);2. The distance of Mandible of the Centre (M) and M points to the horizon at the same point of the buccal (O);3. The distance of Mandible of the Centre (M) and M to the point in the same horizontal line at the side of the tongue(I). Results: The second premolar root tip of the jaw bone under the margin of the thick wall, the wall thickness of tongue in cheek bone lateral side of the wall in the first and second molars, the lower edge of the mandible bone wall, the tongue side of the wall, cheek bone side walls were thicker through 3-D reconstruction measurement than in normal way.Cheek bone was much thicker than the tongue side of the wall. Conclusion: The way of identifying the normal lower in the second premolar and the first and second molar root tip through the three distances by 3-D reconstruction will give us lots of help, such as: Orthognathic operation of the mandible sagittal split SSRO, scaling of cysts, planting of a certain theoretical basis for scientific research and teaching to provide a realistic and practical method.

Objective:To report a case of McCune-Albright syndrome (MAS). Methods:Investigated one case's clinical data of McCune-Albright syndrome and reviewed related literatures. Analyzed the cause of disease,clinical manifestation, diagnosis, treatment and prognosis. Results: The diagnostic criteria of MAS are the fibrous dysplasia of bone (FD), in addition to at least a kind of typical hypercrinemia, and (or) special café-au-lait skin spots. A definite diagnosis can be made by discovering the mutation of Gs α-gene in cyst fluid from the ovarian follicle and exceptional bone tissue by gene diagnosis. Conclusion:MAS is a rare disease in clinic and the most of domestic doctors don't know it yet, so it is easy to be misdiagnosed or missed diagnosis. There is no specific treatment for MAS. We must consider it when encounter these patients with sexual precocity as well as with café-au-lait skin spots, and it will be helpful to treat by earlier discovery.

Objective:To establish a multidrug resistant model of human mucoepidermoid carcinoma using nude mice. Methods:Multidrug resistant MEC/5-FU cells were inoculated intradermally into nude mice. Solid tumors were locally measurable after 10 days and 5-FU was repeated intraperitoneal injected into tumor-bearing mice. The tumor cells in nude mice (MEC/5-FU/NU) were isolated, cultured and examined. Results:The xenografts were similar to the original mucoepidermoid carcinoma from which the cell line was derived. The resistance index (RI) of the MEC/5-FU/NU cells to 5-FU was 27.82. Compared to the MEC, the expressions of ABCB1, ABCB11 and GSTA1 genes and MDR-1 protein increased in the MEC/5-FU/NU cells(P<0.05). Conclusion:The xenograft model is a good model of human multidrug resistant mucoepidermoid carcinoma, and may be useful in studying drug resistance mechanism in vivo.

Objective:To study the residual stress distribution through the thickness of bilayered dental ceramic subjected to thermal stress, in order to improve the restoration. Methods: The finite element model of bilayered dental ceramic was set up based on International Organization for Standardization(ISO) 96936:1999. The residual stresses were calculated in viscoelastic and elastic phases during cooling of dental ceramic to analyze the residual stress distribution. Results: The deformation of core was greater than the veneer ceramics during the cooling period of dental ceramic. The residual stress increased with the decreasing of the temperature approaching the interface of core and veneer ceramics. But it decreased with the increasing of the thickness of veneer ceramics.Conclusion: Thermal compatibility of core and veneer ceramics is very important to the residual stress distribution in the bilayered dental ceramic, which may benefit to All-ceramic restorations. The viscoelastic behavior of ceramic should be taken into account in the thermal compatibility.

Objective:To observe the relationship between the vascular endothelial growth factor (VEGF) and the survival of flap in the rat back which received radiotherapy. Methods: Forty Wistar rats were divided into four groups. A 3×4 cm~2 full thickness dorsal flap with pedicle was prepared at the posterior end. The skin flaps were given~(60)Co radiotherapy in the 2, 4, 6 day postoperation. Group A was given of VEGF in the third, fifth, seventh day. Group B was given a high quantity of VEGF. Group C was the control of Group A,Group D was the control of Group B. Control groups received normal saline. Results: Pathological observation revealed that the survival of flap and blood vessel lumen diameter of group A were higher than that of group B(P<0.05). Group A showed remarkable difference compared with group C(P<0.01). Group B showed remarkable difference compared with group D(P<0.05). Results of fluorescence staining and SDH examination showed that three times injection had better results than one time injection. Conclusion: Three times injection of VEGF has better effect on the viability of rat skin flap than one time injection.

Objective:To evaluate the effects of three bond agents on bond strength of titanium- ceramic system. Methods: The pure titanium specimens were randomly divided into three groups. Three different manufacturers' porcelains(Super Ti22,Duceratin,Titankeramik) were used specially for titanium- ceramic bonding. The specimens in each group were further divided into two subgroups:bond agent group and no bond agent group. Bond strength of specimens was measured by the three- point bending test according to ISO9693. The titanium- ceramic interfaces were investigated by SEM/EDS. Results:The bond strength of Super Ti22(35.84±2.17) MPa and Duceratin(35.45±2.37) MPa with bond agent group was significantly higher than that of no bond agent group(P<0.05). Titankeramik with bond agent group showed a little higher bond strength than without bond agent, but no significant difference in statistics(P>0.05). The interfaces of Super Ti22 and Duceratin with bond agent groups were compact, while there were visible cracks and pores at the interface of other groups. Conclusion:The application of bond agent can improve bond strength of titanium- ceramic system.