In-vitro assessment of the accuracy and reliability of mandibular dental model superimposition based on voxel-based cone-beam computed tomography registration / 대한치과교정학회지

OBJECTIVE@#This study was performed to evaluate the accuracy and reliability of a newly designed method to achieve mandibular dental model superimposition, using voxel-based cone-beam computed tomography (CBCT) registration.@*METHODS@#Fourteen dry cadaveric mandibles and six teeth extracted from patients with severe periodontitis were used to establish 14 orthodontic tooth-movement models. The protocol consisted of two steps: in the first step, voxel-based CBCT mandible superimposition was performed; the reference comprised the external portion of the symphysis, extending to the first molar. The laser-scanned dental model image was then integrated with the CBCT image to achieve mandibular dental model superimposition. The entire process required approximately 10 minutes. Six landmarks were assigned to the teeth to measure tooth displacement, using tooth displacement on the superimposed laser-scanned mandibles as the reference standard. Accuracy was evaluated by comparing differences in tooth displacement based on the method and the reference standard. Two observers performed superimposition to evaluate reliability.@*RESULTS@#For three-dimensional tooth displacements, the differences between the method and the reference standard were not significant in the molar, premolar, or incisor groups (p > 0.05). The intraclass correlation coefficients for the inter- and intra-observer reliabilities of all measurements were > 0.92.@*CONCLUSIONS@#Our method of mandibular dental model superimposition based on voxel registration is accurate, reliable, and can be performed within a reasonable period of time in vitro, demonstrating a potential for use in orthodontic patients.

Transcriptional activation of glucose transporter 1 in orthodontic tooth movement-associated mechanical response / 国际口腔科学杂志·英文版

The interplay between mechanoresponses and a broad range of fundamental biological processes, such as cell cycle progression, growth and differentiation, has been extensively investigated. However, metabolic regulation in mechanobiology remains largely unexplored. Here, we identified glucose transporter 1 (GLUT1)-the primary glucose transporter in various cells-as a novel mechanosensitive gene in orthodontic tooth movement (OTM). Using an in vivo rat OTM model, we demonstrated the specific induction of Glut1 proteins on the compressive side of a physically strained periodontal ligament. This transcriptional activation could be recapitulated in in vitro cultured human periodontal ligament cells (PDLCs), showing a time- and dose-dependent mechanoresponse. Importantly, application of GLUT1 specific inhibitor WZB117 greatly suppressed the efficiency of orthodontic tooth movement in a mouse OTM model, and this reduction was associated with a decline in osteoclastic activities. A mechanistic study suggested that GLUT1 inhibition affected the receptor activator for nuclear factor-κ B Ligand (RANKL)/osteoprotegerin (OPG) system by impairing compressive force-mediated RANKL upregulation. Consistently, pretreatment of PDLCs with WZB117 severely impeded the osteoclastic differentiation of co-cultured RAW264.7 cells. Further biochemical analysis indicated mutual regulation between GLUT1 and the MEK/ERK cascade to relay potential communication between glucose uptake and mechanical stress response. Together, these cross-species experiments revealed the transcriptional activation of GLUT1 as a novel and conserved linkage between metabolism and bone remodelling.

A study on effects of immediate bone grafting at mandibular first molar fresh extraction socket on maintaining alveolar bone height after space closure / 中华口腔医学杂志

Objective@#To investigate the effect of immediate bone grafting at mandibular first molar extraction socket on maintaining alveolar bone height after space closure.@*Methods@#Thirty adult orthodontic patients who need to extract mandibular first molar, totally 38 target teeth, were included. The samples were divided into two groups randomly: graft group and non-graft group. All extraction space was closed orthodontically. Dental models of all patients were taken before extraction (T0), before space closure(T1) and after space closure (T2). The distance, time of the space closure and the velocity of tooth movement were recorded. Probing depth (PD) and clinical attachment level (CAL) at six sites (mesial buccal, buccal, mesial lingual, lingual, distal buccal and distal lingual) on adjacent teeth were measured before extraction (T0) and after space closure (T2). Cone-beam CT (CBCT) was taken at T0 and T2 to compare the changes of alveolar bone height at six sites on adjacent teeth using Invivo Dental 5.0 software.@*Results@#The extraction space in both graft group and non-graft group was closed successfully. However, the space in graft group was closed more slowly than in non-graft group. In graft group, PD and CAL at the six sites on both the second molar and the second premolar did not change significantly after space closure, and CBCT showed that the alveolar bone height of the second premolar had no significant difference after treatment. In non-graft group, alveolar bone height decreased in both adjacent teeth and periodontal attachment loss was found after space closure. On average, alveolar bone height and periodontal attachment of the second premolar decreased (0.75±0.16) mm and (0.64±0.15) mm, respectively. Meanwhile, alveolar bone height and periodontal attachment of the second molar decreased (0.79±0.23) mm and (0.80±0.24) mm, respectively.@*Conclusions@#Bone graft immediately after mandibular first molar extraction could delay alveolar bone resorption and preserve the periodontal attachment of the adjacent teeth during space closure. However, the procedure could slow down tooth movement.

Clinical efficacy of clear aligners in treating bimaxillary protrusion / 中华口腔医学杂志

Objective@#To evaluate the efficiency of clear aligners in treating bimaxillary protrusion patients with first premolar extractions.@*Methods@#Eleven patients with bimaxillary protrusion were selected in this study. All of them were treated by using clear aligners with four first premolar extractions and need maximal anchorage. Cephalometric analysis was carried out before and after treatment.@*Results@#Cephalometric analysis results showed that significant changes in teeth and profile could be detected after clear aligner treatment and no change could be found in skeletal pattern. Upper and lower anterior teeth were retracted. The control of anterior torque and posterior anchorage were effective. The soft tissue analysis showed that position of upper and lower lip was significantly changed which improve the profile of patients. After treatment, the distance of U1 to NA and L1 to NB reduced by (5.19±4.12) mm and (4.53±1.20) mm, respectively. The differences were statistically significant (P<0.01).@*Conclusions@#Bimaxillary protrusion patients who needed premolar extractions and maximal anchorage could be treated with clear aligners.

Precision of three-dimensional printed brackets / 北京大学学报(医学版)

Objective:This study was based on digital orthodontic diagnosis work flow for indirect bonding transfer tray model design and three-dimensional (3D) printing, and the aim of this paper was to inspect the dimensional accuracyof 3D printed brackets, which is the foundation of the follow up work and hoped that will illuminate the clinical application of the digital orthodontics work flow.Methods: The samples which consisted of 14 cases of patients with malocclusion from Department of Orthodontics Peking University were selected, including 8 cases with tooth extraction and 6 cases without tooth extraction.All the 14 patients were taken intra-oral scan (Trios 3Shape,Denmark)and cone-beam computed tomography (CBCT, NewTom 3G volumetric scanner, Aperio Service,Italy)shooting after periodontal treatment.STL data and DICOM data were obtained from intraoral scans and CBCT images.Data segmentation, registration, fusion, automatic tooth arrangement, virtual positioning of orthodontic appliance and conversion the coordinates of malocclusion model were all done with self-programming software.The data of 3D printing model with brackets on it were output finally and printed out with EDEN260V (Objet Geometries, Israel) to make indirect bonding transfer tray.Digital vernier caliper was used to measure the length and width of upper and lower left brackets and buccal tubes on those 3D models after removal of surrounding supporting material by ultrasonic vibration and water-spray.Intra-examiner reliability was assessed by using intra-class correlation coefficients (ICC), and one-sample T test was used to compare the measurements with the standard dimensional data of the brackets.Results: There were significant differences which range in 0.04-0.17 mm between the 13 items out of the 19 measurement items.Except for the length of the lower left premolars''brackets, mean values of the other items were greater than the test value.Conclusion: Although the measurement results in the width of brackets and the width and length of the buccal tubes obtained experimentally were slightly larger than the test value,this may not reduce the accuracy of indirect bonding procedure in clinic necessarily.Whether the differences which range in 0.04-0.17 mm would actually affect the retention and positioning of brackets needs to be confirmed by further studies.

Combination of periodontal, orthodontic and endodontic therapy in upper anterior teeth with hopeless prognosis and long-time follow-up:a case report / 北京大学学报(医学版)

It is complicated to decide the treatment plan of hopeless anterior teeth in esthetic zone due to severe periodontitis, periodontal-endodontic combined lesion or teeth trauma.The optional treatment plan for this kind of teeth includes retention after periodontal treatment, extraction and implant treatment, extraction and prosthodontic treatment and so on.To make an appropriate treatment plan, patients'' periodontal conditions, periodontal biotype, local anatomy, esthetic demand, economic condition and social psychological status should be comprehensively considered.A combine of periodontal, endodontic and orthodontic therapy may achieve a good treatment effect in hopeless anterior teeth with severe periodontal destruction, tooth extrusion and occlusal trauma.In this case, a 20-year-old female who presented with symptoms of bleeding on brushing and upper incisors loosening for 1 month came to the Department of Periodontology, Peking University School and Hospital of Stomatology.The clinical examinations revealed that the patient''s right upper incisor had signs of mobility (Ⅲ°), intrusion of 1-2 mm, and probing depth (PD) of 9-10 mm.The periapical radiograph showed that the alveolar bone of right upper incisor absorbed horizontally to the apex.And the patients showed Angle Ⅱ° malocclusion with Ⅱ° overbite in anterior teeth and maxillary protrusion.A diagnosis of aggressive periodontitis and Angle Ⅱ° malocclusion was made.The treatment of this patient lasts for 5 years which include periodontal initial therapy, orthodontic therapy, guided tissue regeneration (GTR) of right upper incisor and supportive periodontal therapy and the clinical result is fine.A hopeless upper incisor was successfully retained and the longtime clinical condition was stable.The strategy of retention of hopeless upper anterior teeth, the relationship of periodontal treatment and orthodontic treatment, and the indications of periodontal and orthodontic combined therapy were also discussed on the basis of this case.Generally, the positive factors in retention of hopeless teeth includes young age, absence of systemic conditions, strong motivation for maintaining the tooth, single root anatomy, integrated dentition, good response to cause-related therapy, intrabony alveolar bone defect, thick periodontal biotype, and regular supportive periodontal therapy.And in the progress of orthodontic therapy, regular supportive periodontal therapy and good plaque control is extremely important.

Evaluation of cone-beam computed tomography on upper airway changes after alternating rapid palatal expansion and constriction / 北京大学学报(医学版)

Objective:To evaluate the changes of different parts of upper airway after alternating rapid palatal expansion and constriction via three dimensional measurement, compared with the protocol of ra-pid palatal expansion alone.Methods: In the study, 36 patients with retrognathic maxilla were selected and randomized to either group A or group B.The patients in group A were treated with rapid palatal expansion alone.The patients in group B were treated with alternating rapid palatal expansion and constriction.Three dimensional analyses were performed on all pre-and post-treatment cone-beam computed tomography (CBCT) images with the software Dolphin.Results: Two subjects in group B were lost to follow up during the treatment.The gender distributions, ages and all measuring items before treatment had no significant difference between group A and group B (P>0.05).Nasal floor width, nasal lateral width, nasal volume, and nasopharynx volume increased significantly in each group after rapid palatal expansion alone or rapid palatal expansion and constriction (P0.05).No significant difference was observed in the nasal floor width and nasal lateral width increment among the anterior, median and posterior parts in each group either (P>0.05).No significant difference in all the measuring items was observed between the two groups (P>0.05).Conclusion:Alternating rapid palatal expansion and constriction could increase the volume of nasal and naopharynx cavities by the similar way of rapid palatal expansion alone, and had no obvious effect on oropharynx and hypopharynx cavities.

Evaluation of the correction of the skeletal class Ⅲ malocclusion by distalization of the whole mandible dentition with micro-implant anchorage / 北京大学学报(医学版)

Objective:To evaluate the clinical effect of distalizing mandibular dentition with micro-implant in patients with skeletal classⅢmalocclusion.Methods: In the study, 20 patients with skeletal class Ⅲmalocclusion were selected.They are consist of 8 males and 12 female with an age range from 16 to 38 years old and an average age of (21.5±5.6) years.They were treated with straight wire technique and the implant were inserted into the mandibular external oblique line to distlize the lower dentition to a class Ⅰmolar relationships.Cephalometrics films were taken before and after treatment.The changes of hard tissue and soft tissue were analyzed by evaluating 26 measurement measurements.Results: ClassⅠmolar relationships were achieved, and the profile were improved after treatment.ANB increased by(0.80±1.02)°,Wits increased by (1.67±1.74) mm,after treatment(P<0.05).The lower dentition were significantly retracted after treatment with L1-NB distance decreased by(2.64±1.50) mm, P<0.05;the mesial buccal cusp and mesial root of the lower first molars were retracted by (3.26±1.95) mm and (0.79±1.27) mm respectively (P<0.05);the mesial buccal cusp of the lower second molars were retracted by (3.06±1.80) mm (P<0.05).After treatment, mandibular teeth got up-righted distally.From incisors to molar, L1/MP, L5/MP, L6/MP, L7/MP angle decreased by(6.37±8.53)°, (10.59±8.50)°, (11.48±7.22)°, (15.72±7.16)°on average respectively (P<0.05), all of those changes had the statically significant effects.Soft tissue change after treatment, the distance from lower lip to esthetic plane were decreased by (1.70±1.59) mm on average (P<0.05).Conclusion: Distalizing mandibular dentition with micro-implant can get an satisfying result in patients with skeletal class Ⅲmalocclusion, the lower teeth were retracted by controlled tipping movement.

Toxoplasma gondii infection among HBV patients / 中国人兽共患病学报

To investigate the prevalence of Toxoplasma gondii infection among hepatitis B virus (HBV) patients in northern Shaanxi Province,139 patients and 43 healthy controls were recruited.All the plasma was screened for IgG antibody of Toxoplasma gondii.Then,the association between Toxoplasma gondii infection and HBV were analyzed.Results showed that the prevalence of Toxoplasma gondii infection was relative low with just 5.04％ in HBV patients but zero in healthy control.Most of those infected with toxoplasma gondii were male,HBeAg positive or with higher HBV viral load.However,no significant relationship was found between Toxoplasma gondii infection and gender,HBeAg status or viral load in univariate analyses.This study indicated the relative low infection rate of Toxoplasma gondii,which had no association with HBV infection in northern Shaanxi Province.

A cone-beam computed tomography evaluation of maxillary protraction with repetitive rapid palatal expansions and constrictions / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the effects of maxillary protraction combined with repetitive rapid palatal expansions and constrictions (RPE/C) vs. rapid palatal expansion (RPE) alone using cone-beam computed tomography (CBCT).</p><p><b>METHODS</b>Twenty four subjects with maxillary retrusion were recruited and block randomized into either the control group (n = 12) or the RPE/C (n = 12) group.</p><p><b>CONTROL GROUP</b>facemask protraction after RPE. RPE/C group: facemask protraction after RPE/C. 3D reconstruction, landmarks identifying, superimposition and cephalometric analysis were performed to compare the pre-treatment and post- treatment CBCT images.</p><p><b>RESULTS</b>One subject in the RPE/C group was lost to follow up during the treatment. Maxilla moved forward [(2.5±1.0) mm] after maxillary protraction with RPE/C, which was significantly greater than that in the control group [(1.6±0.8) mm] (P < 0.05). The distance of basion to subspinale (Ba-A) increased [(3.1±1.0) mm] in the RPE/C group, which was significantly greater than that in the control group [(2.2 ± 0.9) mm] (P < 0.05). The amount of forward movement of upper first molars was significantly greater in the RPE/C group (P < 0.05).</p><p><b>CONCLUSIONS</b>Maxillary protraction with RPE/C might positively affect the forward movement of maxilla compared with the RPE alone protocol with the early treatment of maxillary retrusion patients.</p>

Development and preliminary application of orthodontic friction dynamic testing apparatus / 北京大学学报(医学版)

Objective:To design and assemble an orthodontic friction prototype testing apparatus and evaluate its performance.Methods: Simulating progressive tooth tipping movement,results of the opera-ting friction trials are reported at different archwire-bracket angulation.Results: An orthodontic friction testing apparatus was designed and developed,by which the complexity of tooth movements observed with in vivo sliding mechanics was simulated and a series of in vitro friction experiments were conducted.This friction testing apparatus enables previously unattainable testing of the orthodontic archwire-bracket-ligation interface.In the passive configuration or the active configuration with second-order angulation,the friction in sliding mechanics was measured.Conclusion: The apparatus presented has the ability to allow for a high standard of basic hypothesis testing,product development and performance evaluation with relative ease.Furthermore,it will be the prototype of a computer-controlled multifunctional friction testing device in the near future.

Computer tomograghy study on periodontal patients with anterior displaced teeth before and after combined orthodontic-periodontal treatment / 北京大学学报(医学版)

Objective:To evaluate evaluation of the changes of alveolar bone height in the periodontal patients with anterior teeth displacement before and after combined orthodontic periodontal treatment with circumferential fibrotomy. Methods: Totally 16 periodontal patients with anterior displaced teeth were analyzed after random clinical trialed as groups with and without circumferential fibrotomy of involving teeth followed by orthodontic intrusion. Evaluations of the changes of alveolar bone were given before and after treatment by means of periapical X ray film and CT scan of the involving teeth. Results: Orthodontic treatment with circumferential fibrotomy can increase the height of crest bone. Alveolar bone height was increased in the patients with circumferential fibrotomy followed by orthodontic intrusion of displaced anterior teeth. Alveolar bone height was increase by 1.2 mm on average in circumferential fibrotomy patient. In the patients with symmetric alveolar bone loss, 0.8 mm increase of alveolar bone height was observed following treatment. For the patients with asymmetric alveolar bone loss, 0.9 mm increase of alveolar bone height was detected in mild bone loss patients, but 1.4 mm and 2.2 mm increase of alveolar bone height were found in moderate and severe bone loss patients, respectively. For patients having the orthodontic treatment without circumferential fibrotomy, the alveolar bone height was increased by 0.1 mm only. Statistic significance was found between the circumferential fibrotomy group and non fibrotomy group. Conclusion: Combined orthodontic periodontal treatment with circumferential fibrotomy could correct the malpositioned teeth, and improve the periodontium conditions and gain the crest bone.

The compensation of dental arch and teeth in patients with skeletal protrusion and deviation of mandible / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the compensation of dental arch and teeth in patients with skeletal protrusion and deviation of mandible.</p><p><b>METHODS</b>Measurement of 11 dental models was performed, midline of palate was defined as central line, the distance of every contact point to the midline was measured in each side. The dental arch symmetry was observed. Occlusion plane was defined as conference plane, the buccal or lingual inclination of posterior teeth in upper and lower arch was measured.</p><p><b>RESULTS</b>Upper arch was asymmetry in these patients, the arch width of deviated side (the side that the chin was deviated to) was broader than the other side. The posterior teeth of upper and lower arch were more buccally and lingually inclined respectively.</p><p><b>CONCLUSIONS</b>Skeletal protrusion and deviation of mandible may result in compensation of dental arch and teeth, the de-compensation is important in pre-operative orthodontic treatment.</p>

Study on the use of temporomandibular joint dysfunction index in temporomandibular disorders / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To study the methodological techniques in measuring the severity of temporomandibulr disorders (TMD) and in evaluating the effectiveness of therapies in clinic.</p><p><b>METHODS</b>Both Fricton's Craniomandibular Index (CMI) and Helkimo's Clinical Dysfunction Index were calculated from 60 TMD patients. Inter-rater reliability was tested to assess the consistency in use between different examiners. Fricton's CMI was used to assess the clinical improvement after accepting a treatment in 21 TMD patients diagnosed as acute disk displacement without reduction.</p><p><b>RESULTS</b>Correlation Coefficient for inter-rater reliability in two groups was 0.879 and 0.939 respectively for Fricton's CMI and 0.744 and 0.838 for Helkimo Clinical Dysfunction Index. Fricton's TMJ dysfunction index was decreased from 0.337 to 0.021 (P < 0.001) and Fricton's CMI was decreased from 0.185 to 0.011 (P < 0.001) after the treatment in 21 TMD patients with disk displacement without reduction.</p><p><b>CONCLUSIONS</b>To avoid using subjective and descriptive report in assessment of the severity of TMD and the effectiveness of therapies, Fricton's CMI is recommended as an objective criteria which is simple in clinical use, and ease in scoring.</p>

The long-term stability of dentition in skeletal class III malocclusion following orthodontic-orthognathic surgery / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To Investigate the changes in dentition at each treatment stage and to get some guidelines for clinical work.</p><p><b>METHODS</b>Thirty-one cephalometric films of skeletal class III malocclusion patients were analyzed. All the patients were treated by orthodontic and orthognathic surgery.</p><p><b>RESULTS</b>During presurgical orthodontic treatment, the lower Incisors were decompensated (labially Proclined by 7 degrees ). The upper incisors were uprighted during surgery following rotation of maxilla. After surgery, the upper anterior teeth kept tipping for ward. While the lower anterior teeth were In stable. The dentition was in good occlusion during observing stage.</p><p><b>CONCLUSIONS</b>Lingually tipped lower Incisors were decompensated after presurgical orthodontic treatment in class III malocclusion patients, and lower Incisors kept in stable during observing stage, while the upper incisor had a little bit relapse.</p>

Severity of dentofacial deformity, the motivations and the outcome of surgery in skeletal Class III patients / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To study the relationship between severity of skeletal Class III malocclusion and the patient's emotional status, as well as motivation for seeking surgical correction and satisfaction with the outcome of the surgery.</p><p><b>METHODS</b>One hundred and forty consecutive Chinese patients with skeletal Class III malocclusion who had been treated with a combined orthodontic and surgical approach were studied. Sixty-seven percent (40 males and 54 females) responded to a questionnaire. Fifty-four percent had two jaw deformities, 32% mandibular hyperplasia and 14% maxillary hypoplasia. Surgical procedures: 77% received two jaw surgeries, 15% maxillary advancement and 8% mandibular setback. This was a retrospective study based on questionnaires with numerical scale ranked answers (0: not at all; 1: a little; 2: moderately; 3: quite a bit; and 4: extremely).</p><p><b>RESULTS</b>ANB angle was significantly negatively correlated with feelings about the nickname related to their facial problems (embarrassment: gamma =-0.30, P < 0.01; worn out gamma =-0.32, P < 0.01; angry gamma =-0.24, P < 0.05). ANB angle also had a significant negative correlation with the reasons for having the surgery (pressure from their friends: gamma =-0.21, P < 0.05, and referred by physician: gamma =-0.24, P < 0.05). Changes in life style as a result of surgery were significantly negatively correlated with the ANB angle before treatment, positive influence on relationships with the opposite sex (gamma =-0.25, P < 0.05), positive influence in social activities (gamma =-0.22, P < 0.05).</p><p><b>CONCLUSION</b>The psychological status before surgery and the outcome following orthognathic surgery in patients with skeletal Class III malocclusion were closely related to severity of the malocclusion.</p>

Effect of changes in the anterior arch dimension on precision of Bolton analysis / 实用口腔医学杂志

Objective:To investigate whether the changes of anterior arch dimension have an impact on the precision of Bolton analysis. Methods:A mathematic-geometric model was used to evaluate the data. Results:The ideal anterior tooth size ratio may need adjustments, depending on the dimensions in radii of the upper and lower anterior dental arches. The ideal ratio is lower for dental arches with a high anterior curvature. There is a deficiency in the upper arch, a flatter anterior segment may compensate for some of the discrepancy and vice versa. Conclusion:An ideal Bolton value may not guarantee an ideal occlusion. Anterior tooth size ratio is not precise in predicting the anterior inter relationship post-treatment.

Facial growth in vertical dimension of Chinese adolescents from 13 to 15 years old with normal occlusion in Beijing / 实用口腔医学杂志

Objective:To observed the longitudinal changes of the facial growth in vertical dimension in the Chinese adolescents with normal occlusion from 13 to 15 years old.Methods:The subjects were from Beijing area and consisted of 9 males and 14 females aged 12.5-13.5 years with Class I skeletal and dental pattern and without previous orthodontic treatment. Serial 2-year- annual cephalometric radiographs were taken and digitalized. Descriptive statistics for the absolute and incremental changes of the skeletal cephalometric measurements were conducted.Results:Significant gender differences in the changes of facial growth in vertical dimension from 13 to 15 years old were observed. Most of the skeletal measurements in males showed greater value than those in females. The number of the measurements which showed gender difference increased with age. The annual incremental changes of TAFH, TPFH, LAFH, U6-PP in males and those of TPFH and RH in females from 13 to 14 years old were greater than those from 14 to 15 years, However, the average increment of L6-MP in males and that of UI-PP, LI-MP, U6-PP and OB in females from 13 to 14 years old were smaller than those from 14 to 15 years old. There was no significant gender difference in TAFH/TPFH from 13 to 15 years of age. Gender difference from 14 to 15 years old was found in the growth of dental-alveolar height. The main dento-alveolar height changes happened in lower incisors and lower molars in males and in the region of upper molars and upper incisor in females.Conclusion:The skeletal facial growth in vertical dimension from 13 to 14 year old falls into the accelerating period. After 14 years old, the growth velocity is slowed down. There are significant gender differences in the skeletal changes of facial growth in vertical dimension from 13 to 15 years old. From 14 to 15 years old, the gender differences are mainly found in the growth of the dento-alveolar height.

Preliminary clinical application of MBT straight wire appliance / 实用口腔医学杂志

Objective: To evaluate the clinical application of MBT straight wire. Methods: 41 cases, 11 males and 30 famales aged 12-42 years old, with malocclusion were treated by MBT straight wire appliance in orthodontic clinics, follow-up was carried out. Results: Satisfactory effects were obtained in 11 completely treated cases, preliminary improvement of occlusion was observed in the other 30 cases being still in the treatment. Conclusion: MBT straight wire appliances may be used in the treatment of various malocclusion, but special consideration should be taken according to the type of occlusion in each case.

Effects of GWe on the sIL-2R levelsl in chronic persistent hepattis patients / 中国免疫学杂志

The level of serum soluble interleukin 2 receptor(sIL-2R)was studied in 29chronic persistent hepatitis (CPH) patients and in 18 normal individuals.It was found that sIL-2R level was significantly higher in the CPH patients than that in normal individuals(P