Objective:To study the effects of the alternate rapid maxillary expansion and constriction(Alt-RAMEC)with maxillary protraction on different parts of upper airway by CBCT.Methods:20 Angle Class Ⅲ patients aged 9-12 years were included,and CBCT images were taken before treatment and after Alt-RAMEC with maxillary protraction,the total volume of the upper airway,the volume of each part of the nasopharynx,palatopharynx,linguopharynx and laryngopharynx,the cross-sectional area of the division in-terface,and the minimum cross-sectional area were measured after 3D reconstruction using Dolphin software,the data were analyzed using SPSS 26.0 software.Results:The total upper airway volume,nasopharyngeal volume,and palatopharyngeal volume were in-creased by the average of 1 385.39 mm3(P=0.013),546.74 mm3(P=0.011)and 768.03 mm3(P=0.035)respectively after Alt-RAMEC with maxillary protraction treatment;the area of the nasopharyngeal and palatopharyngeal division interface increased by 73.79 mm2(P=0.002),the cross-sectional diameter by 1.41 mm(P=0.037),and sagittal diameter by 1.52 mm(P=0.022)respectively;however,there was no statistically significant change in the volume,minimum cross-sectional area,partition area,and partition transverse and sagittal diameters of the linguopharynx and laryngopharynx(P＞0.05).Conclusion:Alt-RAMEC with maxil-lary protraction can significantly increase nasopharyngeal and palatopharyngeal volumes,with no significant effect on the linguopharyn-geal and laryngopharyngeal segments of the airway.

Objective:To investigate the effect of head model in improving the photographic ability of interns during the photographic training of oral facial image in pediatric dentistry.Methods:A total of 60 interns of stomatology school affiliated to Xinjiang Medical University were randomly divided into head model training group, mutual training group and clinical probation group for photographic training. After the training, the interns in the three groups were evaluated for the photographic time, the level of photos, etc., by the training test and satisfaction level of volunteers. Besides, the head model training group was conducted by questionnaire survey. One-way analysis of variance and least significant difference analysis were used to analyze the data between groups by SPSS 17.0 software.Results:There was no statistical difference between the head model training group and the mutual training group in photographic time and level of photos, while both of them were much better in the head model training group and mutual training group than in the clinical probation group ( P<0.05). There was no statistical difference between the head model training group and the mutual training group in the satisfaction level, while that was lower in the head model training group than in the clinical probation group ( P<0.05). According to the questionnaire survey, most interns in the head model training group acknowledged its effects. Conclusion:The use of head model can help improve the oral photographic ability, and promote the teaching effect and efficiency in photographic training.

Objective To investigate the effects of triamcinolone acetonide combined with tanshinone ⅡA (Monomer of tanshinone)injection on oral submucous fibrosis(OSF)and the effect of serum TGF-β1 and IL-6 on patients.Methods 92 patients with OSF,w ho came to the hospital for treatment from April 2013 to April 2016,were selected and randomly divided into control group(46 cases)and experimental group(46 ca-ses).They were respectively treated with triamcinolone acetonide and triamcinolone acetonide combined with tanshinone injection.The two groups were treated for 3 courses and were followed up for 12 months.The VAS scores and mouth opening were compared between the two groups before the treatment and 2,4,6,and 12 months after the treatment,The serum TGF-β1,IL-6,lesion area and the changes of quality of life oral health impact scale(OHIP-14)scores of two groups were compared before and after treatment.Results 6 months after follow-up,the maximum mouth opening of the two groups was significantly increased than that before treatment,and improvement speed and improvement degree of the experimental group were better than those of the control group(P<0.05).After 2,4,6 and 12 months follow-up,the VAS scores of the two groups were significantly lower than those before treatment,and the experimental group were significantly lower than those of the control group(P<0.05),but the VAS score of two groups after 12 months increased than that after 6 months,and the control group was more obvious(P<0.05).After treatment,the levels of TGF-β1 and IL-6 of the experimental group were significantly lower than those of the control group and before the treat-ment(P<0.05);After treatment,the lesion area of the experimental group was significantly lower than that of the control group,and the OHIP-14 score was significantly higher than that of the control group,and the difference was significant compared with this group before treatment(P<0.05).Conclusion The local injec-tion treatment of triamcinolone and tanshinone injection has godd efficacy of OSF patients,and significantly re-duces the levels of TGF-β1 and IL-6 in serum.

Objective:To investigate the effects of bone morphogenetic protein 2(BMP-2)expression in the related periodontal tissue on bone remodeling under different distracting force during rapid tooth movement by resistance reduction and distraction. Methods:1 2 Beagle dogs were randomly divided into 4 groups as follows:5 d distraction,1 5 d distraction,1 5 d distraction and 1 0 d retaining and 1 5 d distraction and 90 d retaining.4 4 were distalized.6 teeth in each group were randomly assigned to re-sistance and distracting method,resistance and conventional method and conventional method,and there were 2 teeth in each group.Moving teeth models were prepared regularly.BMP-2 expression was examined by immunohistochemistry.Results:The BMP-2 positive expression of the 3 groups of different distraction schedule showed similar distribution area,and it reached peak at the end of 1 5-day distration,but the group of resistance and distracting method showed the maximum peak(P <0.05)and maximum tooth movement(P <0.01 ).In different stages of distraction,the positive expression in the group of resistance reduc-tion and conventional method was higher than in the group of conventional method but lower than the group of resistance reduction and extraction method(P <0.05).There was no significant difference in BMP-2 positive expression among 3 groups when retai-ning was 90 d(P >0.05).Conclusion:Resistance reduction with sustained strong distracting force can significantly increased the positive expression of BMP-2 and effectively accelerate new bone formation in periodontal tissue.

BACKGROUND:To make a better preparation for orthodontic tooth, we investigate the changes in the localization of the anterior wal of the maxilary sinus and maxilary tuberosity, analyze the development of the maxila, and detect the bone mass of the maxila and development timing. However, the use of Auto-CAD software has not been reported to localize the anterior wal of the maxilary sinus and maxilary tuberosity. OBJECTIVE: To investigate the localization and growth of the anterior wal of the maxilary sinus and maxilary tuberosity in 300 children aged 4-14 years from the Han ethic group in Urumqi, Xinjiang Uygur Autonomous Region, China. METHODS: Totaly 300 children, 4-14 years of age, admitted at the Stomatological Hospital of Urumqi, Xinjiang Uygur Autonomous Region, China, were enroled. According to Helman’s dental developmental staging, these children were divided into five groups: groups IIA, IIC, IIIA, IIIB, IIIC. Auto-CAD software was used to analyze the panoramic radiographs of the maxila and mandible. The tracing of each radiograph was digitized by translating the reference points onto an X-Y coordinate system. The straight line that passed the point where the nasal septum intersected with the hard palate (point O) and the point where the medial wal of maxilary sinus intersected with the hard palate (point PA) was designated as the X axis. The straight line that was vertical to the X axis and passed through the point O at a right angle was designated as the Y axis. The X and Y coordinate values of reference point were calculated. And then O point was set as (0, 0), and the point where the posterior wal of maxilary tuberosity intersected with the hard palate (PP) was set as (PPX, PPY). Colected data were analyzed statisticaly to understand the changes in the localization of PA and PP at different stages of dental development. RESULTS AND CONCLUSION:The change of point PA had on significant differences between the five groups (α > 0.05). Point PP grew obviously in a horizontal rearward and vertical downward manner from stage IIA to IIIA; this point only presented a horizontal rearward growth from stage IIIA to IIIB and only a vertical downward growth from stage IIIB to IIIC. This period was the time of the second molar eruption, indicating that the second molar eruption is helpful to the vertical growth of the maxila.

BACKGROUND:Cigarette smoking can seriously damage the periodontal tissues and root, and the nicotine in tobacco accelerates the progression of periodontal diseases. OBJECTIVE: To investigate the effect of different doses of nicotine on the expression of cyclooxygenase-2 mRNA in the periodontal tissue during orthodontic tooth movement. METHODS: Totaly 110 Sprague-Dawley rats were randomly divided into blank control group (n=10), normal saline group (n=25), 0.5 mg/kg nicotine group (n=25), 0.75 mg/kg nicotine group (n=25), 1 mg/kg nicotine group (n=25). Rats in the normal saline groups were injected intraperitonealy with 0.1 mL normal saline, and those in the three nicotine groups were respectively injected with 0.5, 0.75, 1 mg/kg nicotine tartrate solution. Except the blank control group, the unilateral maxilary first molars of rats in the other four groups were exposed to 50 g force. At 1, 3, 5, 7, 14 days under force, the rats were sacrificed to take the maxilary tissues. Hematoxylin-eosin staining was used to observe the changes of periodontal tissues, immunohistochemical staining was employed to count positive cels, andin situ hybridization staining was adopted to detect the mean absorbance value of cyclooxygenase-2 in the periodontal tissues. RESULTTS AND CONCLUSION:The number of odontoclasts and the expression of cyclooxygenase-2 in the nicotine groups were higher than those in the non-nicotine groups. With the increasing dose of nicotine, the number of odontoclasts gradualy increased, and the difference was statisticaly significant (P < 0.05). At 7 days under force, the number of odontoclasts reached the peak. With the increasing dose of nicotine, the positive expression intensity of cyclooxygenase-2 was also increased, and the difference was statisticaly significant (P < 0.05). The expression of cyclooxygenase-2 reached peak at 5 days under force. These findings indicate that with the increasing dose of nicotine, the number of odontoclasts and the expression intensity of cyclooxygenase-2 are both increased at the same time point under force. During the orthodontic tooth movement, the intake of nicotine can damage the periodontal tissue, and the dose of nicotine can directly influence the severity of damage to the periodontal tissue.

BACKGROUND:The cytokine has an effect of immunoregulation and immediate induction in the reconstruction of periodontal tissue. At present, the role and mechanism of hepatocyte growth factor involving the reconstruction of periodontal tissue under orthodontic force are stil unclear.
OBJECTIVE:To explore the mechanism underlying hepatocyte growth factor in the tooth movement and periodontal tissues remodeling under the inflammation periodontal tissue condition.
METHODS:Thirty Sprague-Dawley rats, aged 8 weeks, were used to establish periodontitis model. The obtained model was randomly divided into two groups:inflammatory control group and inflammatory force group. In the force group, rats were treated with the fixed orthodontic appliance by 50 g forces in the maxil ary first molars. After 1, 3, 5, 7 and 14 days of tooth movement, five rats were sacrificed respectively. Hematoxylin-eosin staining and immunohistochemistry methods were used to analyze the expression and distribution of hepatocyte growth factor in the periodontium for rats at different tooth movement stages.
RESULTS AND CONCLUSION:Hematoxylin-eosin staining results showed that, remodeling of periodontal tissues existed in al groups. (2) The immunohistochemical results showed that hepatocyte growth factor had positive expression in periodontal tissue, and the distribution was even in the control group. In the force group, hepatocyte growth factor expression was increased and reached the peak on day 5, then began to decline. Osteoblast, fibroblast and osteoclast were strongly expressed. The findings indicate that, hepatocyte growth factor is involved in the periodontal tissues remodeling under orthodontic force, and inflammation can increase the expression of hepatocyte growth factor in periodontal tissue.

BACKGROUND:As an important cytokine, interleukin-6 regulates immune responses in inflammation sites and has an autocrine/paracrine activity that stimulates osteoclast formation and bone resorption, which is related to bone remodeling during orthodontic tooth movement.
OBJECTIVE:To investigate the effects of orthodontic force on the expression of interleukin-6 mRNA in the periodontal tissue of rats.
METHODS:In situ hybridization was performed to measure the expression of interleukin-6 mRNA at 1, 3, 5, 7, 10 and 14 days after the application of orthodontic force on the maxil ary first molars of rats.
RESULTS AND CONCLUSION:The expression of interleukin-6 mRNA was observed at a low level in the normal periodontal tissue of rats. After the application of force, the induction of interleukin-6 mRNA was observed to reach a maximum on day 3 and to decline thereafter. The expression of interleukin-6 mRNA can be evoked by orthodontic force but with a certain self-limiting. As a multifunctional cytokine, interleukin-6 plays a very important role in periodontal remodeling during orthodontic tooth movement.

Objective To establish a three-dimensional finite element model of rapid canine tooth movement by reducing resistance and distracting procedures,and to discuss canine distal movement and force distribution of periodontium,and to provide theory basis for its clinical application.Methods Through 64-slice spiral scanning,temporomandibular joint (TMJ),the mandible,lower jaw denture section phantom DICOM data were obtained.Mimics software,Geomagic Studio 8.0 software,Unigraphics NX software,and Ansys11.0 software were mixed,and the three-dimensional finite element model were established under the conventional condition to move the canine (model 1 ),rapid canine movement through distracting osteggenesis of the periodontal ligament (model 2),rapid canine movement tooth movement through reducing resistance and distracting method (model 3),the strength were carried on three kind of models and the canine,the pericementum,the tooth socket bone stress distribution were observed.Results The biggest displacements on those three models occured in canine crown on 1/3,biggest displacement quantity:model 3 ＞model 2 ＞model 1,and the canine crown displacement reduced gradually from crown to the root point; in the model 1 most greatly equivalent stress mainly concentrated in the middle of distal alveolar crest,but in the models 2 and 3 most greatly equivalent stress centralism area shifted liguodistal alveolar crest.Conclusions In the process of canine distal movement,reducing bone resistance,can accelerate the tooth moving speed effectively and simultaneously,the canine has distal motion tendency.While under the action of force,the canine tends to move ligually with the canine distal movement,and thus appropriate measures should be taken to prevent canine lingual rotation in clinical work.

Objective The facial soft tissue features were studied in Urumqi adolescent with skeletal Ⅱ malocclusion by using a polar coordinate system. Methods Sixty samples of Urumqi adolescent with skeletal Ⅱ malocclusion were selected, each one underwent cephalometrics analysis and 32 cephalometric parameters from the samples were measured. The mean and standard deviations of each measurement were compared by statistical analysis (t-test). Results Polar distance in male was larger than female, showing significant difference between male and female. Po-Ns/Po-Li, Po-Ns/Po-Bs, Po-Ns/PoPgs, Po-Ns/Po-Gns, and Po-Ns/Po-Mes showed significant difference between male and female. Polar angles in female were larger than male, with a significant difference between male and female.Conclusion Statisticalstudies on features of facial soft tissue show significant differences between male and female. The polar coordinate analysis system is a good index to study the growth magnititude and direction of facial soft tissue during growth and development or before treatment and after treatment.