The bracketless invisible aligner technique has been considered as a new developed orthodontic technique since its appearance during the period of late 1990s. It is characterized with the advantages of more aesthetic, comfortable, simple, high-efficient and predictable compared with current traditional orthodontic techniques depending on brackets and wires for orthodontic tooth movements. There have been many opportunities for further development and clinical application for the technique with the developments of material sciences, computer software and hardware technology, rapid prototyping techniques, et al. Nevertheless, kinds of difficulties and challenges have been and should be met either at present or in the future for this relatively new technique which just occurred around 10 years ago. The histories, developments with opportunities and challenges and prospects of the technique will be reviewed and discussed in this paper.
Humans ; Orthodontic Appliances ; Tooth Movement Techniques

Artemisia lactiflora is an important medicinal plant in China. The antitumor and antioxidant activities of the extracts of 54 endophytic fungi from the plant were screened via MTT assay and DPPH scavenging radical assay, respectively. The bioactive strains were identified based on similarity of 5.8S gene and internal transcribed spacer (ITS) sequences. The results showed that extracts from ten (18.5%) isolates exhibited antitumor activity, and which from two (3.7%) isolates exhibited antioxidant activity. The Alternaria sp. GYBH47 strain was simultaneously having antagonistic activity against HL-60 leukemia, MCF-7 breast and COLO205 colon cell lines, and Phomopsis sp. GYBH42 strain having cytotoxic and antioxidant activities. The results indicated that endophytic fungi from Artemisia lactiflora are potential resources to find valuable bioactive components.
Antineoplastic Agents ; chemistry ; pharmacology ; Artemisia ; microbiology ; Biphenyl Compounds ; metabolism ; Cell Line, Tumor ; Endophytes ; chemistry ; classification ; physiology ; Free Radical Scavengers ; chemistry ; pharmacology ; Fungi ; classification ; physiology ; Humans ; Picrates ; metabolism

Objective To investigate the clinical effectiveness of coronary artery bypass grafting through descending thoracic aorta in elderly patients with coronary heast disease and to decrease the post-operative complication.Methods Thirteen elderly patients underwent coronary bypass surgery with minimally invasive direct coronary artery bypass (MIDCAB).Age range from 70 to 82 years with a mean of(72.1?6.0)years.Patients suffered from multi vessel disease.Many minimally invasive techniques of“Y”blood vessel graft anastomosis,anastomosis of blood vessel graft to descending aorta,minimally invasive direct,thoracoscope assist were used.Results All patients were survived.The mean duration of intubation was (6.9?0.9) hours.The average ICU stay was (2.5?0.5)days.No patients received blood transfusion.During the short-term follow-up(3 to 14 months) patients had no complaint of angina,Conclusions The technique of“Y”blood vessel graft anastomosis,descending aorta blood vessel graft,minimally invasive direct and thoracoscope assist in combination with coronary artery bypass grafting is a safe and cost-effective new procedure for elderly patients with multi-coronary artery disease.

Objective To observe the occlusal contacts in intercuspal position(ICP) in adolescent patients after orthodontic treatment.Methods Fourteen adolescent patients after orthodontic treatment were selected as experimental group and 17 healthy adolescents and young adults with normal occlusion were selected as control group.The occlusal contact in ICP in the two groups were recorded with T-Scan Ⅱ system and compared.Results When the total of force (TOF) were 1/10 TOFmax,1/4 TOFmax,1/2 TOFmax,3/4 TOFmax and TOFmax,the number of occlusal contacts in the anterior segment in the experimental group were 1.5(1.0),3.0(1.3),4.5(3.3),5.5(3.0),5.5(3.3),which were significantly larger than that in control group[0.0(0.3),0.0(0.6),0.3(0.5),0.3(1.0),0.0(1.8),P＜0.05].There were no significant difference in the area of occlusal contacts in the posterior segment between experimental group and control group(P＞0.05).The center of force(COF) in the experimental group located significantly more mesially than that in control group.The value of ICP contact time in experimental group was 0.192(0.141) s and no significant difference was found between experimental group and control group [0.163(0.200) s].Conclusions Although the patiants achieved normal occlusion after orthodontic treatment,their anterior teeth received more occlusal force than those in healthy adolescents and young adults with normal occlusion.

OBJECTIVETo analyze the distribution of single nucleotide polymorphisms (SNP) of growth hormone receptor (GHR) gene in Chinese Han ethnic population.

METHODSThe sample of 106 unrelated healthy Chinese Hans was studied by sequencing exons of the GHR gene to detect SNP.

RESULTSThere were 6 SNP spots identified in exon 6 and exon 10. Five of them were found in exon 10, and one in exon 6. There were differences between the allele frequencies of the SNP we found and those in the NCBI database. The highest heterozygosity of the SNP was found at 1630 A > C (I526L), which was 47.6%. The SNP 1483 A > C (P477T), 1735 A > C (P561T) and 1319 G > T (C422F) had polarity change. The SNP 536 A > G in exon 6 from the NCBI database was not detected in this population. The allele distribution of SNP was in good unity with the Hardey-Weinberg equilibrium.

CONCLUSIONIt is suggested that the SNP of GHR are unevenly distributed and different in different ethnic populations.

Asian Continental Ancestry Group ; ethnology ; Female ; Gene Frequency ; Humans ; Male ; Polymorphism, Single Nucleotide ; Receptors, Somatotropin ; genetics

Objective To investigate the mechanical properties of Ni-Ti wires with direct electric resistance heat treatment(DERHT) method in three-point bending tests. Methods Two superelastic Ni-Ti wires(wire A: Smart SE, wire B: SENTALLOY SE, 0.406 mm ×0.559 mm) and 2 heat-actived Ni-Ti wires(wire C: Smart SM, wire D: L&H TITAN, 0.406 mm ×0.559 mm) were selected. They were heattreated using the DERHT method by a controlled electric current(6. 36 A) applied for different period of time[0(control), 1.0, 1.5, 2. 0, 2. 5 seconds). Then, a three-point bending test was performed under controlled temperature (37 ℃ ) to examine the relationships between the deflection and the load in the bending of wires. Results After DERHT treatment, the plateau in the force-deflection curve of superelastic Ni-Ti wires and heat-actived Ni-Ti wires were increased. When the wires were heated for 2. 0 seconds and deflected to 1.5 mm, the loading force of A, B, C and D Ni-Ti wires increased from (3.85 ± 0. 11 ),(3.62±0.07), (3.28±0.09), (2.91 ±0.23) Nto (4.33 ±0.07), (4.07 ±0.05), (4.52±0.08),(3.27 ± 0. 15 ) N respectively. Conclusions DERHT method is very convenient for clinical use. It is possible to change the arch form and superelastic force of NiTi wires. The longer the heating time is, the more the superelastic characteristics of the wires are altered.

OBJECTIVETo record and analyze the characteristics of condyle movement before and after functional treatment in Angle class II division 1 malocclusion (II(1)) patients.

METHODSTwenty Angle II(1) patients were included in the study and 20 Angle I patients without temporomandibular disorders symptoms served as controls. Computer aided diagnosis axiograph (CADIAX) was used to record the condyle movement in Angle II(1) patients and that caused by functional appliance treatment during mouth opening and closing.

RESULTSThe tracing were vertically displayed. Value Z [L: 2.21 (1.01) mm, R: 1.12 (1.02) mm] and sagittal condylar inclination [L: 12.89 (9.12) degrees, R: 12.12 (8.89) degrees] were increased significantly in Angle II(1) patients compared with those in control group (P < 0.05). After functional treatment, the condyle movement in Angle II(1) patients was close to normal (P > 0.05).

CONCLUSIONSTypical characteristics of condyle movement were found in Angle II(1) patients and it was stable and repeatable. Functional therapy had a positive effect on temporomandibular joint function in Angle II(1) patients.

Female ; Humans ; Male ; Malocclusion, Angle Class II ; physiopathology ; therapy ; Mandibular Condyle ; physiopathology ; Temporomandibular Joint ; physiopathology

OBJECTIVETo explore the possible factors causing the increase of rabies cases and to provide references for the development of related prevention and control strategy in Hunan.

METHODSData was collected and analyzed on epidemic situation of rabies in the past ten years, and studies were carried in some counties.

RESULTSFrom 1994 to 1999, the annual cases sustained between 17 and 78. However, the number of cases has continued to increase since 2000. The annual reported cases in 2001 and 2002 were 311 and 313, and accounted for 34.8% and 30.0% of the total cases in the whole country respectively. The epidemic areas were mainly located in the south and middle parts of Hunan. Furthermore, the epidemic areas had been expanding. In 1997, human rabies cases were only reported in 7 cities but increased to 12 cities in 2004.

CONCLUSIONFactors as increasing number but low inoculating rate to dogs, and incorrect treatment on the wounds etc. might have served important roles for the recurrence of rabies. Hence, it is necessary to take comprehensive preventive measures to control and prevent the epidemics of rabies in Hunan.

Adolescent ; Adult ; Aged ; Child ; Child, Preschool ; China ; epidemiology ; Female ; Humans ; Incidence ; Male ; Middle Aged ; Rabies ; epidemiology

Early and longterm prognosis depended on the extents of acute myocardial infarction and residual myocardial function. Many clinical methods have been evaluated to determine their ability to estimate the size of myocardial infarcts. But because of many disadvantages simplified QRS scoring system, used with standard 12-lead EKG, was developed, which is noninvasive, inexpensive and easily releatible. Therefore, the correlation between QRS and peak CK,killip classification were evaluated in 55 patients with initial acute myocardial infarction at the Chung-Ang University, Yong-San and Pil-Dong Hospital during the period from January 1983 to December, 1986. The results were as follows : 1) The average QRS score of the anterior wall infarction is 7.1 and that of the inferior wall infarction is 4.5 and there is a statistical significance(p<0.01). 2) In the acute myocardial infarction, the correlation coefficeient between the QRS score and the killip classification is 0.66(p<0.05). 3) In the acute myocardial infarction, the average QRS score is 6.3 and the correlation coefficient between the leak CK and the QRS score is 0.52(p<0.05). 4) In the anterior wall infarction, the average QRS score is 7.1 and the correlation coefficient between the peak Ck and QRS score is 0.48(p<0.05). 5) In the inferior wall infarction, the average QRS score is a 4.5 and the correlation coefficient between the leak CK and QRS score is 0.79(p<0.05).
Classification ; Electrocardiography ; Humans ; Infarction ; Myocardial Infarction* ; Prognosis

OBJECTIVETo evaluate the stability of mini-screw implant during different healing periods in the unloaded conditions.

METHODSSixty titanium mini-screws were used in this study. A total of 10 New Zealand white rabbits were randomly divided into 5 groups according to different healing periods. The stability was evaluated biomechanically at different time points. One-way ANOVA and correlation analyses were used.

RESULTS(1) After 4 weeks and 8 weeks of healing, maximal pull-out loads were (179.68 +/- 24.65) N and (212.06 +/- 42.51) N, respectively. The maximal torques were (0.47 +/- 0.13) N.m and (0.61 +/- 0.16) N.m, respectively. (2) Significant difference in maximal torque was found between 4 week and 8 week healing groups. (3) Both reverse torque and pull-out load significantly correlated with healing time.

CONCLUSIONSFourth-week is a critical time point in the progress of osseointegration. Within 8 weeks of healing process, the stability of implant was significantly correlated with healing time.

Animals ; Bone Screws ; Dental Implantation, Endosseous ; Dental Implants ; Dental Stress Analysis ; Male ; Orthodontic Anchorage Procedures ; Osseointegration ; physiology ; Rabbits ; Stress, Mechanical ; Time Factors ; Titanium ; Torque ; Wound Healing ; physiology