Supramolecular Hydrolase Mimics in Equilibrium and Kinetically Trapped States.

The folding of proteins into intricate three-dimensional structures to achieve biological functions, such as catalysis, is governed by both kinetic and thermodynamic controls. The quest to design artificial enzymes using minimalist peptides seeks to emulate supramolecular structures existing in a catalytically active state. Drawing inspiration from the nuanced process of protein folding, our study explores the enzyme-like activity of amphiphilic peptide nanosystems in both equilibrium and non-equilibrium states, featuring the formation of supramolecular nanofibrils and nanosheets. In contrast to thermodynamically stable nanosheets, the kinetically trapped nanofibrils exhibit dynamic characteristics (e.g., rapid molecular exchange and relatively weak intermolecular packing), resulting in a higher hydrolase-mimicking activity. We emphasize that a supramolecular microenvironment characterized by an optimal local polarity, microviscosity, and ß-sheet hydrogen bonding is conducive to both substrate binding and ester bond hydrolysis. Our work underscores the pivotal role of both thermodynamic and kinetic control in impacting biomimetic catalysis and sheds a light on the development of artificial enzymes.

RECQL1 plays an important role in the development of tongue squamous cell carcinoma.

BACKGROUND/AIMS: RECQL1, a member of the human RECQ helicase family, participates in DNA repair. Recent reports showed that RECQL1 silencing in cancer cells resulted in mitotic catastrophe, which prevented tumor growth in murine models. However, its therapeutic potential has never been examined in tongue squamous cell carcinoma (SCC). METHODS: To explore the role of RECQL1 in the development of tongue SCC, we used RNA interference technology to silence RECQL1 in SCC-9 and SCC-15 human tongue SCC cell lines, and to subsequently evaluate its effects both in vitro and in vivo. RESULTS: After RECQL1 was silenced in SCC cells by siRNA, we observed downregulation of RECQL1 mRNA and protein in cancer cells. RECQL1 is one of the predicted miR-203 targets, and we found that miR-203 downregulated the expression of RECQL1 at the post-transcriptional level. RECQL1-shRNA or miR-203 overexpression inhibited SCC-9 cell growth. In addition, there was accumulation of cells in the sub-G1 fraction and increased apoptosis 72 h post-transfection. In addition, knockdown of RECQL1 led to a strong anticancer effect, as the tumorigenicity of SCC-9 cells was inhibited in vivo. Moreover, we found that two immunosuppressive factors were also significantly downregulated upon RECQL1 knockdown or miR-203 overexpression in vitro. CONCLUSION: Collectively, these results indicate that RECQL1 plays an important regulatory role in cancer cell proliferation and tumor progression.

[Study on promoting bone formation in osteoporotic zebrafish by lithium-doped hydroxyapatite nanowires].

PURPOSE: To observe the regulatory effect of lithium-doped hydroxyapatite nanowires on bone metabolism in osteoporotic zebrafish induced by dexamethasone. METHODS: Pure hydroxyapatite nanowires(nHA) and hydroxyapatite nanowires doped with 10% lithium ions (Li-nHA) were prepared by using hydrothermal method, and then material characterization was performed. The juvenile zebrafish cultured for 3 days(3dpf) were selected and co-cultured with nHA and Li-nHA extracts up to 7dpf. A negative(0.1% DMSO) control group was set up and transgenic zebrafish Tg(ola.sp7:nlsGFP) was used to select the best concentration for promoting bone formation. The osteoporotic zebrafish were induced by dexamethasone and incubated with nHA and Li-nHA extracts. The wild-type zebrafish was stained with alizarin red and the osteogenic differentiation was observed in transgenic zebrafish. Real-time quantitative PCR was adopted to detect osteogenic maker genes, such as zinc finger transcription factor (SP7), alkaline phosphatase (ALP), osteoprotegerin (OPG), Runt related transcription factor 2(Runx2) and osteocalcin (OCN). Statistical analysis was performed with GraphPad Prism 9.3 software. RESULTS: nHA and Li-nHA promoted bone formation and up-regulated expression levels of ALP, OCN, Runx2, SP7 and OPG of osteoporotic zebrafish. Compared with nHA, Li-nHA significantly increased the mineralization specific staining area and cumulative optical density of zebrafish bone, and the expression of osteogenic maker genes was also significantly increased. CONCLUSIONS: Doping lithium ions in nano hydroxyapatite can enhance its osteoinductive properties, and Li-nHA can effectively improve bone formation of osteoporotic zebrafish.

Stress and movement trend of lower incisors with different IMPA intruded by clear aligner: a three-dimensional finite element analysis.

BACKGROUND: During the intrusion of lower incisors with clear aligners (CAs), root disengagement from the alveolar bone often occurs, resulting in serious complications. This study aimed to determine the potential force mechanism of the mandibular anterior teeth under the pressure of CA, providing theoretical data for clinical practice. METHODS: In this study, a 3D finite element model was established, including the CA, periodontal ligament, and mandibular dentition. Incisor mandibular plane angles were set as 5 groups: 90°, 95°, 100°, 105°, and 110°. The 4 mandibular incisors were intruded by 0.2 mm, while the canines were the anchorage teeth. The stress, force systems, and potential movement trends of mandibular anterior teeth were obtained. RESULTS: The compressive stress of the incisors was concentrated in the lingual fossa, incisal ridge, and apex. With the increase in IMPA, the moment of central incisors changed from lingual crown moment to labial crown moment, with the turning point between 100° and 105°, but the center of resistance (CR) was always subjected to the force toward the lingual and intrusive direction. The force and moment toward the labial side of the lateral incisors were greater than those toward the central incisors. The canines always tipped distally and received extrusive force with no relationship with IMPA. CONCLUSIONS: With the increase in the initial IMPA, the direction of labiolingual force on the mandibular incisors was reversed. However, the root of the lower incisors always tipped labially, which indicated fenestration and dehiscence.

BAFF induces spleen CD4+ T cell proliferation by down-regulating phosphorylation of FOXO3A and activates cyclin D2 and D3 expression.

The TNF ligand family member "B cell-activating factor belonging to the TNF family" (BAFF, also called BLyS, TALL-1, zTNF-4, and THANK) is an important survival factor for B and T cells. In this study, we show that BAFF is able to induce CD4(+) spleen T cell proliferation when co-stimulated with anti-CD3. Expression of phosphorylated FOXO3A was notably down-regulated and cyclins D2 and D3 were up-regulated and higher in the CD4(+) T cells when treated with BAFF and anti-CD3, as assessed by Western blotting. Furthermore, after FOXO3A was knocked down, expression of cyclin D1 was unchanged, compared with control group levels, but the expression of cyclins D2 and D3 increased, compared with the control group. In conclusion, our results suggest that BAFF induced CD4(+) spleen T cell proliferation by down-regulating the phosphorylation of FOXO3A and then activating cyclin D2 and D3 expression, leading to CD4(+) T cell proliferation.

Sagittal maxillary growth pattern in unilateral cleft lip and palate patients with unrepaired cleft palate.

OBJECTIVE: The objective of the study was to examine the sagittal maxillary growth pattern during the mixed and permanent dentition in unilateral cleft lip and palate (UCLP) patients with unrepaired cleft palate. PATIENTS AND METHODS: A total of 30 nonsyndromic UCLP patients with unrepaired cleft palate were included, 15 of whom were in mixed dentition and 15 in permanent dentition.Cephalograms were analyzed and compared in the patients with UCLP who have operatively undergone repair with both the lip and palate as well as normal subjects. RESULTS: The UCLP patients with unrepaired cleft palate in mixed dentition showed decreased anterior-posterior length of the maxilla. The UCLP patients with unrepaired cleft palate in permanent dentition demonstrated an almost normal maxillary growth. The operated-on patients both in mixed and permanent dentitions showed maxillary retrusion as well as decreased maxillary length. CONCLUSIONS: There appears that there may be the potential normal maxillary growth in UCLP patients, and early surgical repair of the cleft palate may affect sagittal maxillary growth pattern in patients with cleft.

The effects of maxillary protraction and its long-term stability--a clinical trial in Chinese adolescents.

The purpose of this study was to evaluate the effect of reverse pull headgear (RPHG) in the treatment of Class III malocclusions in the late mixed and early permanent dentition and its long-term stability at the time when facial growth was close to completion. The treatment group comprised 22 subjects (12 males and 10 females, mean age: 11.38 ± 0.69 years). The control group included 17 subjects (7 males and 10 females, mean age: 11.54 ± 1.07 years). The mean RPHG treatment time was 1.5 ± 0.95 years and the observation time for the control group was 1.75 ± 0.83 years. For each subject, lateral cephalograms were obtained before (T1) and after (T2) treatment or observation. These cephalograms were traced and analyzed and the differences between T1 and T2 values were examined with paired t-tests. Of the 22 treated cases, 10 patients were followed up until at the mean age of 16.18 years (T3). Since there was no relapse in anterior crossbite, the long-term effects of RPHG were evaluated by measuring the maxillary and mandibular skeletal changes. The follow-up patients were divided into two groups based on the change in ANB: a stable group (decrease in ANB < 2 degrees) and an unstable group (decrease in ANB > 2 degrees). The skeletal effects of RPHG in treating Class III anomalies just before or at the beginning of the pubertal growth spurt include protraction of the maxilla and dentition and inhibition of forward growth of the mandible. With regard to the long-term change, a slight alteration in the position of the maxilla and in the position and growth direction of the mandible resulted in a slight decrease in ANB in the stable group. The slight retrusion in the maxilla, combined with the significant protrusion in the mandible and the more horizontal mandibular growth direction, resulted in a decrease in ANB in the unstable group. This indicated that the maxilla remained relatively stable and that the unstable factor was continuing mandibular growth during the pubertal and post-pubertal period. For patients with an excessive mandible, orthopaedic therapy should start at the beginning of pubertal growth and orthodontic fixed appliance should follow immediately after RPHG so that mandibular growth in the sagittal direction during puberty or even after pubertal growth may be effectively inhibited.

The effects of a newly designed twin-slot bracket on severely malpositioned teeth--a typodont experimental study.

The aims of this study were to design a twin-slot bracket featuring two horizontal slots and to examine its efficiency in tooth displacement. Based on the structure of a traditional edgewise bracket, an additional slot was added to a twin-slot bracket and the prototype products were fabricated for the typodont experiments. The orthodontic correction of malpositioned canines was conducted on a typodont to examine the efficiency of the twin-slot bracket in tooth displacement compared with a single-slot edgewise bracket. Three modalities of tooth movement requiring a heavy force moment, namely, axial rotation, mesiodistal tipping, and bodily translation, were conducted. The canine positions before and after simulation were measured and the changes identified. Statistical analysis was undertaken using a t-test to determine the significance of the differences in canine repositioning between the two bracket types. The results showed that in the twin-slot bracket group, the treatment changes in the canine position by derotation and uprighting were 40 +/- 3 and 25 +/- 2 degrees, respectively, compared with 20 +/- 5 and 10 +/- 2 degrees in the edgewise group (P < 0.01). When retracted into an extraction space with an initial 10 degrees of mesial tip, the mesiodistal angulation of the canines in the twin-slot bracket group remained unchanged while in the edgewise group the canines became distally tipped by 5 +/- 2 degrees (P < 0.01). The twin-slot bracket significantly increased the bracket width without reducing the interbracket span and therefore can generate increased force moments within the bracket, leading to an improved manipulation in tooth repositioning.

[A novel magnetic orthopedic appliance in treatment of preadolescent mild skeletal Class â ¢ patients].

PURPOSE: This study was to develop an intraoral Class Ⅲ orthopedic appliance using attractive magnetic forces, and investigate the effect of magnetic orthopedic appliance (MOA-Ⅲ) on skeletal and dental structures in mild skeletal Class Ⅲ children. METHODS: Thirty patients (12 boys and 18 girls) with mild skeletal Class Ⅲ jaw discrepancies were treated with MOA-Ⅲ. The average age was 9 years 3 months at the beginning of the treatment. The mean treatment period was 6.6 months. A paired t test was carried out to evaluate 40 parameters measured on cephalometric radiographs. Another 18 untreated patients (7 boys and 11 girls) according to upper criteria served as control group. SPSS15.0 software package was used for data analysis. RESULTS: The MOA-Ⅲ produced significant positive changes in maxillomandibular relationship. The maxilla was displaced anteriorly with clockwise rotation. The mandible showed slight downward and backward rotation. No significant changes were displayed in the length of the mandibular body and mandibular ramous. Significant labial tipping of the upper incisors and lingual tipping of lower incisors were noted after treatment. The measurement of soft tissues indicated that the upper lip moved forward and the lower lip retruded backward. In control group, most of the cephalometric measurements were not significantly changed except for some mandibular skeletal measurements and soft tissue measurements. CONCLUSIONS: By comparing to the untreated control, this type of magnetic orthopedic appliance is effective in the early treatment of mild skeletal Class Ⅲ malocclusion children.

[Preparation of lyophilized lentiviral vector of bone morphogenetic protein 2].

PURPOSE: To construct recombinant lentiviral vectors of bone morphogenetic protein 2(BMP-2) gene and prepare a stable lyophilized state. METHODS: The BMP-2 gene lentiviral vector was constructed by recombinant DNA technology and mixed with different stabilizers in an appropriate proportion and then lyophilized. The optimum stabilizer was selected according to the appearance and virus titer after being lyophilized. The quality of lyophilized product was measured by thermal stability of the virus, PCR and gene sequencing. SPSS13.0 software package was used for statistical analysis. RESULTS: Recombinant BMP-2 lentiviral vector was successfully constructed. 10% trehalose, 1% bovine serum albumin, 3%mannitol and 0.5% gelatin in group B showed good protection on BMP-2 gene lentiviral vector. The virus titer decreased 0.42 LgPFU/mL after being lyophilized, which was better than group A, C and the control group and the difference was statistically significant (P<0.05); Lyophilized protective agent made from group B still maintained a good appearance at 37 degrees centigrade after 28 days and the virus titer decreased 0.63 LgPFU/mL. The virus titer in liquid lentiviral infection control group decreased rapidly to 2.37 LgPFU/mL 1 week later and the difference between the two groups was statistically significant (P<0.05); PCR and gene sequencing showed that the target gene information after redissolve had no loss or mutation. CONCLUSIONS: Appropriate selection of lyoprotectants can effectively protect the biological stability of recombinant BMP-2 gene lentiviral vector.

Effects of a novel magnetic orthopedic appliance (MOA-III) on the dentofacial complex in mild to moderate skeletal class III children.

INTRODUCTION: The objective of this study was to evaluate the changes of skeletal and dental structures in mild to moderate skeletal Class III children following the use of a new magnetic orthopedic appliance (MOA-III). METHODS: A total of 36 patients (14 boys and 22 girls, mean age 9 years and 5 months) who presented with a mild to moderate skeletal Class III jaw discrepancy were treated with MOA-III. Another group of 20 untreated patients (9 boys and 11 girls, mean age 9 years and 2 months) with the same level of deformity served as the control group. The average treatment time was 6.6 months. Radiographs were taken at the same time intervals for both groups. A paired t test was used to determine the significant differences before and after treatment, and a two-sample t test was used to analyze the differences between the treatment and control groups. RESULTS: The anterior crossbite in all subjects was corrected after MOA-III therapy. The maxillomandibular relationship showed favorable changes (ANB, Wits, overjet increased significantly, P < 0.001). The maxilla was anteriorly positioned (SNA, ptm-A, ptm-S increased significantly, P < 0.001) with clockwise rotation (PP-FH increased, P < 0.001). The mandible showed a slight downward and backward rotation (SNB decreased, P < 0.05, MP-SN, Y-axis increased, P < 0.05). The length of the mandibular body showed no significant changes (Go-Pg, P > 0.05). Significant upper incisor proclination and lower incisor retroclination were observed (UI-NA increased, P < 0.001, LI-NB, FMIA decreased, P < 0.001). The upper lip moved forward, and the lower lip moved backward (UL-EP increased, P < 0.001, LL-EP decreased, P < 0.05). In the control group, most of the parameters showed normal growth, except for some unfavorable mandibular skeletal and soft tissue changes (Go-Pg, Go-Co, MP-SN, N'-SN-Pg' increased, P < 0.001). Significant positive changes were induced with the MOA-III appliance compared to the untreated group. CONCLUSIONS: The MOA-III was effective for the early treatment of a mild to moderate Class III malocclusion in children.

[Effect of the presurgical nasoalveolar molding using computer-aided design technique].

OBJECTIVE: To develop a new method of presurgical nasoalveolar molding based on computer-aided design technique. METHODS: Twenty patients(16 boys, 4 girls) with complete unilateral cleft lip and palate(UCLP) who received presurgical nasoalveolar molding were recruited as the treatment group. Twenty patients(15 boys, 5 girls) with complete UCLP who did not receive presurgical orthopedic treatment were selected as the control group. All parameters of the digital maxillary model were measured using the Rapidform XOR3 software. The statistical analysis was performed with SPSS 15.0. RESULTS: A'-X and B-Il were reduced significantly after presurgical nasoalveolar molding. However, the mean alveolar height [F- hight (3.7 ± 1.1) mm, F'-height (4.6 ± 0.9) mm] decreased significantly after treatment(P <0.05). There were significant differences between the treatment group and the control group(P<0.05). CONCLUSIONS: Maxillary alveolar morphology could be improved in UCLP infants treated with computer-aided presurgical nasoalveolar molding. The width of the cleft could be reduced and the maxillary midline corrected effectively. However, the alveolar height decreased significantly after the treatment.

[Study on the relationship between some genetic factors and peak bone mineral density in Beijing young women].

OBJECTIVE: To evaluate the relationship between the peak bone mineral density (PBMD) and vitamin D receptor (VDR), estrogen receptor (ER) allelic variants in Beijing young women. METHODS: From March, 2000 to July, 2001, one hundred and fifty-nine young healthy women (25 - 37 years old) in Beijing were voluntarily enrolled in the study. (1) BMD were measured by dual energy X-ray absorptiometry (DXEA) at lumbar and hip. (2) The polymorphism of VDR and ER genes were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). (3) The relationship between BMD and polymorphism of VDR and ER genes were examined. RESULTS: (1) Lumber BMD was positively correlated to height, weight and body mass index (BMI), whereas, the femoral neck BMD only to weight, and the other sites of hip BMD to BMI. (2) Although subjects with the VDR bb genotype had higher BMD than those with Bb genotype at lumber, femoral neck, inter and troch, no significant difference was found (P > 0.05). (3) In Ward triangle, subjects with ER PP genotype had significantly lower BMD than those in ER Pp and pp genotypes (P < 0.05). (4) Women with BbPP genotype combination had lower BMD levels at lumber and hip, and with bbPP and Bbpp genotypes combination significantly higher lumber BMD levels than BbPP genotype (P < 0.05). However, the differences of BMD among subjects with different VDR and ER genotypes became not significant after adjusting the confounder of body weight. CONCLUSIONS: (1) Body weight and BMI play important roles to PBMD of Beijing women. (2) There was no significant difference of BMD levels between VDR genotypes at any site. (3) PvuII polymorphism of ER gene was associated with low Ward triangle BMD. (4) There was significant relationship between the combination of ER and VDR polymorphisms at lumbar and hip BMD. Our data suggest that genetic variation at the ER locus, singly and in relation to the VDR locus, may influence the attainment and maintenance of peak bone mass in young women.

[Study of the mandibular growth phases and quantities in Shanghai adolescents].

PURPOSE: To study the growth phases and quantities of mandible in Shanghai adolescents. METHODS: The samples included 480 Shanghai adolescents from 8-20 years of age, 240 were male and 240 were female. Both male and female groups were divided into 6 consecutive developmental periods according to cervical vertebral maturation stages. Their cephalometric radiographs were measured and analyzed. Independent-sample t test was conducted by SPSS 15.0 software package. RESULTS: The total mandibular length (Co-Gn) increased significantly from CVMS1 to CVMS2 and CVMS3 to CVMS4 in both male and female group. For male the maximum increase was from CVMS3 to CVMS4 (P<0.01,average 9.54 mm), while female was from CVMS1 to CVMS2(P<0.01,average 9.09 mm). The height of mandibular ramus (Co-Go) increased continuously from CVMS2 to CVMS5 in male group, the significant increase was observed from CVMS2 to CVMS3 (P<0.01, average 8.80 mm). The significant increase in female group was observed from CVMS1 to CVMS2 (P<0.01, average 6.51 mm). In male group, the greatest increase of the mandibular base length (Go-Pog) appeared from CVMS3 to CVMS4 (P<0.01, average 7.55 mm), while in female group, it occurred from CVMS1 to CVMS2 (P<0.01, average 5.73 mm). CONCLUSIONS: The growth amounts of total mandibular length (Co-Gn), mandibular base length (Go-Pog) and ramus length are different at every CVM stages in male and female groups. The present finding will help to make reasonable diagnosis and treatment planning.

[Effect of semi-fixed Twin-block appliance on temporomandibular joint remodeling].

PURPOSE: To evaluate quantitatively the effect of semi-fixed Twin-block appliance on the temporomandibular joint remodeling during the Class II malocclusion treatment. METHODS: Twenty two Class II division 1 patients treated with semi-fixed Twin-block appliance were included. Pre- and post-orthopedic treatment cephalometric data were analyzed with SPSS13.0 software package for paired t test. RESULTS: The mandibular condylar growth was directed superiorly(2.7mm) and posteriorly (3.6mm) (P<0.01), the glenoid fossa was displaced in a inferior(1.5mm) (P<0.01) and posterior (0.8mm)(P<0.05) direction, the effective TMJ changes showed a pattern similar to condylar growth in a superior(4.2mm) and posterior(2.7mm) direction(P<0.01), the mandibular rotation was slightly clockwise(P>0.05). CONCLUSIONS: The application of semi-fixed Twin-block appliance shows its effectiveness on patients' compliance and the remodeling in temporomandibular joint, contributing to the correction of sagittal jaw relationship discrepancy.

[The effectiveness of asymmetric extraction in treatment of Class II division 1 malocclusions].

PURPOSE: To analyze hard and soft tissue profile changes before and after asymmetric extraction treatment of Angle Class II division 1 malocclusion. METHODS: Thirty patients of Angle Class II division 1 malocclusions (11 males, 19 females, average age 13.6 years) were divided into two groups according to their extraction approach. In asymmetric extraction group, 2 first maxillary premolars and 1 first mandibular premolar were extracted. In the control group, all 4 first premolars were extracted. Lateral cephalometric radiographs were taken before and after treatment to compare hard and soft-tissue changes between the two groups, and the cephalometric measurements were analysed by SAS6.12 software package for independent sample t test. RESULTS: In comparison of the changes between the two groups, significant differences in dentoskeletal measurements were observed with NAPog, SNA, ANB, MP-SN and with the inclinations of the upper and lower incisors (P<0.01). Significant differences in soft-tissue changes were also observed in the thickness of upper lip, the Z angle (P<0.01) and the nasolabial angle (P<0.05). Compared to the profile before treatment,only inclination of lower incisors changed significantly after treatment (P<0.01). CONCLUSIONS: Asymmetric extractions is feasible in treatment of Class II division 1 malocclusions evidenced by retractions of both upper and lower incisors and improves sagittal soft-tissue profile. Supported by Research Fund of Science and Technology Commission of Shanghai Municipality (Grant No.08DZ2271100).

[Identification of cell apoptosis during premaxillary suture expansion in rat].

PURPOSE: To identify the incidence of cell apoptosis during premaxillary suture expansion. METHODS: Forty SD rats were randomly allotted into experimental and control groups. The experimental animals were subjected to premaxillary suture expansion by a helix spring with (200+/-10)g initial force. They were sacrificed on day 1, 2, 3 and 5(n=5). The sequence of histological changes and osteoblast proliferation in the premaxillary suture were evaluated by hematoxylin and eosin(HE) and toluidine blue staining. Cellular apoptosis was identified by ssDNA immunostaining. The difference between experimental and control groups was analyzed by Student's t test with SPSS 15.0 software package. RESULTS: The width of premaxillary suture was enlarged 1 day after expansion and osteoblasts were accumulated along the suture. After 2 days of stretching, the number of the osteoblasts increased to the peak. New bone deposition was identified on day 3 and projection of suture with bone trabeculae was apparent on day 5. ssDNA immunostaining showed few apoptotic cells in premaxillary suture during natural growth. Upon expansion, cell apoptosis was identified in osteoblasts along the suture and the osteocytes embedded in premaxillary bone, especially on day 2 and day 3(P<0.01). CONCLUSION: Apoptotic cell death might regulate the growth modification of premaxillary suture upon mechanical stretching.

[Establishment of cervical vertebral skeletal maturation of female children in Shanghai].

PURPOSE: To establish a method for quantitatively evaluating skeletal maturation of cervical vertebrae of female children in Shanghai. METHODS: The samples were selected from lateral cephalometric radiographs of 240 Shanghai girls, aged 8 to 15 years. The parameters were measured to indicate the morphological changes of the third (C3) and fourth (C4) vertebrae in width, height and the depth of the inferior curvature. The independent-sample t test and stepwise multiple regression analysis were used to estimate the growth status and the ratios of C3, C4 cervical vertebrae by SPSS 15.0 software package. RESULTS: The physical and morphological contour of C3, C4 cervical vertebrae increased proportionately with the increment of age. The regression formula for indicating cervical vertebral skeletal age of female children in Shanghai was expressed by the equation Y= -5.696+8.010 AH3/AP3+6.654 AH3/H3+6.045AH4/PH4 (r=0.912). CONCLUSION: The regression formula resulted from morphological measurements quantitatively indicates the skeletal maturation of cervical vertebrae of female children in Shanghai.

[Effect of high pull J hook headgear on root resorption during orthodontic treatment].

PURPOSE: The purpose of this study was to evaluate the effect of high pull J hook headgear(HPHG) on root resorption of maxillary incisors during orthodontic treatment. METHODS: Sixty female adolescent subjects who had finished orthodontic treatment were selected. They were either Class I or Class II division I cases treated with standard edgewise appliances. Half of the patients(30 cases) had an additional HPHG to assist upper anterior teeth retraction. They were matched to the other 30 cases with age and type of malocclusion. Panoramic radiographs taken before and after the orthodontic treatment were used to evaluate the degree of root resorption on upper incisors. Chi(2) test was used for statistical analysis. RESULTS: The incidence of root resorption on upper incisors was significantly increased after orthodontic treatment in both HPHG and non-HPHG groups (P<0.01). Compared to the non-HPHG group, more teeth in HPHG group showed moderate or severe root resorption (P<0.01). Some cases even encountered extremely severe root resorption. CONCLUSION: A combination of HPHG might lead to more severe root resorption on maxillary incisors during orthodontic treatment.

[The feasibility and reliability of Pancherz's analysis in evaluating the treatment effects of bite-jumping on skeletal class II malocclusion].

OBJECTIVE: This study was designed to conduct an in-depth evaluation on Pancherz's analysis. METHODS: A typical Class II case with bite-jumping therapy was selected for the whole process of Pancherz's Analysis. The skeletal growth modification and dental compensation were examined and portioned for their respective contribution to the correction of excessive overjet and Class II molar relationship. RESULTS: The following traits and properties of Pancherz's analysis were found: (1) A fixed reference system characterized by SN and OLp was established which led to an accurate detection of the moving objects. (2) Skeletal and dental changes were separated for evaluation, which resulted in a true assessment of the bite-jumping on growth pattern modification.(3) A segmental examination for dental changes indicated the magnitude of skeletal modification. Conclusion Pancherz's analysis is a feasible and reliable evaluation system which could reflect with accuracy the skeletal and dental effects caused by bite-jumping therapy.