Objective To assess the reliability and validity of standardized facial photographs under natural head position (NHP) in assessment of mandibular asymmetry cases. Methods Standardized facial photographs (SFP) and posteroanterior cephalometry (PAC) were taken under natural head position from 25 mandibular asymmetry eases (14 boys and 11 girls), aged 14 to 29 years old. Distances from 8 landmarks to the vertical reference line were measured. The difference and the asymmetry ratio of two sides were calculated respectively. The relationship between the measurements of SFP and PAC were compared, and the repeatability of landmarks was assessed. Results Six measurements were significant different between two sides, 3 from SFP and 3 from PAC. Measurements from two ways were correlated a cer-tain extent. The repeatability of landmarks was satisfied. Conclusion Measurements from standardized facial photographs under NHP pres-ent a clinical useful method to quantify mandibular asymmetry.

Objective To investigate the reliability and validity of three reference planes used in Wits appraisal measurement in evaluation of sagittal jaw relationship. Methods Lateral cephalo-radiography was performed before and after treatment in 25 patients with class Ⅱ division 1 of four premolars extraction. Wits appraisals were measured using the functional occlusal plane(FOP), bisected occlusal plane(BOP), and maxillary-mandibular bisector (MMB), respectively. The effect of different reference planes on Wits appraisals was analyzed. Results FOP and BOP showed a statistically significant change in their cant after treatment(P0.05). MMB Wits had the highest correlation with ANB angle (r=0.79, P

Objective To investigate the reliability of cast measurements by comparing Photoshop and conventional hand-held method. Methods Maxillary standard plaster models from 10 orthodontic cases with crowding were enrolled in this study. The space available and the space required of anterior region were measured by using Photoshop in the digital pictures or conventional method used by 5 observers respectively.The measurement results of the same sample among every observer were analyzed with ANOVA, and the difference between the 2 methods was calculated and paired t test was used to analyze the data. Results The repeatability of measurement results was not good when the space available was measured with conven-tional method by different observer( M1 ～ M5 ), and the measurement results of M1 were significantly different from that of M3 and M5 respectively( P ＜ 0.05 ). The repeatability of measurement results was relatively good when the space available was measured by using Photoshop, and the measurement results of M5 were significantly different from other observers ( P ＜ 0.05 ). The measurement results of space required measured by different observer were very close, and the reproducibility was excellent when they were measured by means of Photoshop or conventional methods. Conclusion There were no much difference between Photoshop and conventional method to measure the required space. Photoshop had significant advantage over conventional method when available sRace was measured.

BACKGROUND: Heat-activated nickel-titanium (HANT) wire is a new type of arch wire in orthodontic treatment, characterizing by well memory alloy ability and uneasily deformation. However, environmental temperature may affect its performance.OBJECTIVE: To compare the effects of HANT and common nickel-titanium wire in clinical application.METHODS: A total of 80 patients who have accepted and finished orthodontic treatment in the First Affiliated Hospital of Sun,Yat-sen University from July 2006 to November 2008 were randomly divided into two groups. The common group was treated with common arch wire in aligning and leveling stages, while the HANT group was treated using HANT in aligning and leveling stages. Tooth extracted cases were matched to non-tooth extracted cases. Indicators, such as time span for alignment, total treating time, times for wire breaking, times for bracket shedding, and times for return visits, were measured.RESULTS AND CONCLUSION: There was significant difference in treating time and times for wire breaking between the two groups (P < 0.05), but there was no significant difference in the times for bracket shedding. Anaphylactic response, toxic reaction,and other adverse reactions were not observed in the HANT group. Therefore, HANT wire can simplify orthodontic operation,shorten operation time beside the chair, save the total treating time, and reduce chances of shedding brackets and breaking wires.

BACKGROUND:Because of convenient source, multi-lineage differentiation and low immunogenicity, bone marrow mesenchymal stem cels are the ideal cel type to serve as vectors of transgenic cels in pain management. However, the replicative senescence and smal amount of cels obtained from the bone marrow restrict the application of bone marrow mesenchymal stem cels in pain research. OBJECTIVE:To construct human telomerase reverse transcriptase (hTERT)-immortalized rat bone marrow mesenchymal stem cels as transgenic celular vectors for pain therapy. METHODS:Bone marrow mesenchymal stem cels were obtained from whole rat bone marrow, and then transfected with a lentivirus containing the hTERT (pLV-Puro-EF1α-hTERT) folowed by puromycin selection. hTERT expression and telomerase activity in these transfected cels were determined by RT-PCR and TRAP. Morphological changes, capacity of cel growth and multi-lineage differentiation, chromosome karyotype and tumorigenicity were observed in vitro. Moreover, the expression of cel surface molecule, Nestin, MHC-I and MHC-II in transfected cels were also detected by flow cytometry and immunocytochemistry. RESULTS AND CONCLUSION: The bone marrow mesenchymal stem cels geneticaly modified by hTERT could be cultured and passaged through 30 generations in vitro. Compared to the primary and negative transfected cels, the hTERT-modified bone marrow mesenchymal stem cels showed higher expression of hTERT mRNA, telomerase activity and cel proliferation. Most of transfected cels stayed at G2/M and S stages. The proliferation index of the transfected cels were increased dramaticaly. The positive rates of CD29, CD44 and CD90 were over 70%, but the positive rates of CD34 and CD45 were less than 5%. Transfected cels were positive for Nestin in the cytoplasm, but negative for MHC-1 and MHC-11. In addition, this cel line continued to exhibit the characteristics of fibroblastic bone marrow mesenchymal stem cels, including phenotype, differentiation into osteoblasts, adipocytes and neuron-like cels. No chromosome abnormality and tumor formation were observed in this experiment. Taken together, these data suggests that the rat bone marrow mesenchymal stem cels immortalized by hTERT gene are constructed successfuly and stil maintain major stem cels characteristics, which provide safe and stable cel vectors as research base for pain therapy.

Objective To evaluate the reliability of the panoramic radiographs for diagnosing mandibular asymmetry.Methods A total of 25 cases with no asymmetry in chief complaint or in appearance were selected for symmetry group.Pa and PAC from 16 cases of facial asymmetry were selected for asymmetric group.Marker points were fixed,a reference line and the reference plane drawn,and then relevant measurement items determined.The repeatability of the fixed position was observed.The difference of all measurement items between the left and right on Pa in symmetry group and asymmetric group were compared respectively and the asymmetric rate of corresponding measuredvalues on two sides between two groups were observed too.Correlation test was used to evaluate the measured-values on Pa and PAC in asymmetric group.Results Dispersion became smaller with the help of reference line and reference plane.And the dispersion was larger when Me was used as a marker other than MF.Most measured-values in symmetry group on Pa and all measured-values in asymmetric group on Pa showed statistically significant difference (P＜ 0.05).The mean difference of CP-GoP distance representing the vertical measured-value was 4.73 mm (P＜0.01); and the mean difference of GoP-MF distance representing the horizontal measured-value was 5.77 mm (P＜0.01).The horizontal measurements on PA and PAC showed closer correlation (r=0.78～0.85,P＜0.01) while the vertical was poorer (r=0.64,P＜0.01).Conclusions This study suggests that marking assisted with reference line and reference plane could get a more repeatable fixed-point on Pa.MF point could be used as a fixed-point for measuring mandibular asymmetry on Pa and the Pa measurement can be used to evaluate mandibular asymmetry.

BACKGROUND:Percutaneous vertebroplasty and kyphoplasty are both effective in the treatment of osteoporotic vertebral compression fractures, but different in the distribution and dispersion of bone cement. ＜br> OBJECTIVE:To analyze the factors affecting the bone cement dispersion within the vertebral body in treatment of osteoporotic vertebral compression fracture with vertebroplasty or kyphoplasty. ＜br> METHODS:A total of 41 patients with osteoporotic vertebral compression fractures were included, and divided into three groups:group A (22 cases receiving high viscosity bone cement vertebroplasty treatment), group B (5 cases receiving high viscosity bone cement kyphoplasty), group C (14 cases receiving low viscosity bone cement vertebroplasty treatment). The groups A and C were divided into subgroups according to bone cement injection volume, time from fracture to operation, preoperative degree of vertebral compression. The distribution and dispersion of bone cement in the vertebra were reconstructed by the CT three-dimensional imaging and volume rendering analysis. ＜br> RESULTS AND CONCLUSION:In the three groups, after operation, relative dispersion area and relative dispersion volume in the vertebrae had no obvious difference, and the bone cement could al diffuse to upper and lower lamina cross the vertebral midline. There was no significant difference in bone cement diffusion coefficient among the three groups. In a certain range, the bone cement injection volume and bone cement dispersion volume was positively correlated. In groups A and C, bone cement diffusion coefficient decreased with the increasing of bone cement injection volume, time from fracture to operation, and the compression degree of the fractured vertebrae, but showed no significant correlation with bone cement viscosity.

BACKGROUND:Vertebroplasty and kyphoplasty can effectively repair osteoporotic vertebral compression fractures, but postoperative change of stress in the fractured vertebrae and adjacent vertebrae can lead to new fractures. OBJECTIVE:To analyze the stress changes of the fractured and adjacent vertebrae with different bone cement injection volume by three-dimensional finite element method. METHODS:One healthy adult male volunteer was selected for lumbar spine CT scan. The acquired images were imported for three-dimensional reconstruction using Mimics. The three-dimensional model was smoothed, polished and denoised by Geomagic software, and then the solid mode was built under Workbench Ansys. The osteoporotic vertebral compression fracture model in L2-L4 segments was established after assignment. Bone cement of 1, 2, 4, 6 mL was injected into the L3 vertebrae respectively and distributed in the middle of the vertebrae as spherical shape. 500 N pre-load was applied on L2 surface with an additional moment of 50 N·m. The lower surface free degree of L4 was restrainted. The L2-L4 forward flexion, extension, right flexion and axial rotation on the right side were stimulated to compare the stress changes of fractured vertebrae and adjacent vertebrae before and after the bone cement injection with different volume. RESULTS AND CONCLUSION:The stresses of fractured and adjacent vertebrae after the bone cement injection were significantly increased; meanwhile, the stresses of fractured and adjacent vertebrae increased with the increase of bone cement injection volume, which may be one of the factors leading to the compression fractures of adjacent vertebrae.

BACKGROUND:Vertebroplasty and kyphoplasty can effectively repair osteoporotic vertebral compression fractures, but bone cement injection can cause the change of stress in the fractured vertebrae and adjacent vertebrae after surgery, leading to new fractures.
OBJECTIVE: To analyze the stress changes of the fractured vertebrae and adjacent vertebrae after vertebroplasty with different elastic modulus bone cement by a three-dimensional finite element method.
METHODS: One healthy adult male volunteer was selected for lumbar spine CT scan. The acquired images were imported for three-dimensional reconstruction using Mimics. The three-dimensional model was smoothed, polished and denoised by Geomagic software, and then the solid mode was built under Workbench Ansys. An osteoporotic vertebral compression fracture model in L2-4 segments was established after assignment. Bone cement (4 mL) with different elastic moduli (8 000, 4 000, 2 000 and 1 000 MPa) injected into the L3 segment distributed in the middle of the vertebrae as spherical shape. 500 N pre-load was applied on the L2 surface with an additional bending moment of 50 N?m. The lower surface free degree of L4 was restrained. The L2-4 forward flexion, posterior extension, right flexion and axial rotation on the right side were stimulated. The stress changes of the fractured vertebrae and the upper and lower adjacent vertebrae before and after bone cement injection with different elastic moduli were compared.
RESULTS AND CONCLUSION:The stress of the fractured vertebrae and adjacent vertebrae were significantly increased compared with that before operation. With the increase of elastic modulus, the stress of the fractured vertebrae increased, but there were no changes in the stress of adjacent vertebrae. These findings indicate that the elastic modulus of bone cement may be a method to reduce new fractures of the fractured and adjacent vertebrae after bone cement injection.

Objective:To investigate the reparative efficacy and mechanism of pressure-adjustable macroporous antibacterial hydrogel in the treatment of infected wounds.Methods:Staphylococcus aureus was used to establish wound infection models in healthy C57BL/6 mice. The models were divided into 3 groups subjected to 3 different treatments: a negative control group with no hydrogel treatment (group A), a control group treated by common medical hydrogel (group B) and an experiment group treated by pressure-adjustable macroporous antibacterial hydrogel (group C). On days 1, 3, 6, 9 and 12, the effects of 3 treatments were compared on the wound area and the number of bacterial colonies under scab, on the apoptosis of fibroblasts based on the changes of type Ⅰ procollagen, and on the inhibition of inflammation during wound repair by detecting the expression of interleukin-6 (IL-6) and tumor necrosis factor (TNF-α).Results:On days 1 and 3, there was no significant difference between the 3 groups in the wound area ( P>0.05), but on days 6, 9 and 12, there were significant differences between the 3 groups in the wound area ( P<0.05). On day 6, the wound areas in group B (1.23 cm 2 ± 0.16 cm 2) and in group C (1.14 cm 2 ± 0.12 cm 2) were significantly smaller than that in group A (1.56 cm 2 ± 0.16 cm 2) ( P<0.05), but there was no significant difference between groups B and C ( P>0.05). On days 9 and 12, the wound areas in group B (0.97 cm 2 ± 0.13 cm 2 and 0.76 cm 2 ± 0.10 cm 2) and in group C (0.66 cm 2 ± 0.06 cm 2 and 0.48 cm 2 ± 0.07 cm 2) were significantly smaller than those in group A (1.49 cm 2 ± 0.11 cm 2 and 1.39 cm 2 ± 0.13 cm 2), and those in group C were significantly smaller than those in group B (all P<0.05). On day 1, there was no significant difference between the 3 groups in the number of bacterial colonies under scab ( P>0.05). On days 3, 6, 9 and 12, the numbers of bacterial colonies under scab in groups B and C were significantly smaller than that in group A ( P<0.05), and that in group C was significantly smaller than that in group B ( P< 0.05). The nucleic acid electrophoresis showed that the grayscale bands in group C were significantly darker than those in groups A and B. The early apoptosis rate of the fibroblasts in group C[low-right positive fluorescence (LR%): 9.72%] was significantly lower than that in group A (43.99%) and that in group B (38.43%), and that in group B was significantly lower than that in group A ( P<0.05). On day 12, the ratio of the gray values of IL-6 and β-actin (0.64 ± 0.10) and the ratio of the gray values of TNF-α and β-actin (0.34 ± 0.05) in the fibroblasts in group C were significantly higher than those in group A (1.22 ± 0.21 and 0.60 ± 0.14) and in group B (0.88 ± 0.02 and 0.41 ± 0.06) ( P<0.01). Conclusion:The pressure-adjustable macroporous antibacterial hydrogel is an effective treatment of infected wounds and its mechanism may be related to the reduced apoptosis of fibroblasts.