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

OBJECTIVETo observe the occlusal contacts in intercuspal position(ICP) in adolescent patients after orthodontic treatment.

METHODSFourteen 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.

RESULTSWhen 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].

CONCLUSIONSAlthough the patients achieved normal occlusion after orthodontic treatment, their anterior teeth received more occlusal force than those in healthy adolescents and young adults with normal occlusion.

Adolescent ; Bite Force ; Case-Control Studies ; Dental Occlusion ; Humans ; Incisor ; Orthodontics ; Young Adult

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.

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

OBJECTIVETo investigate the mechanical properties of Ni-Ti wires with direct electric resistance heat treatment (DERHT) method in three-point bending tests.

METHODSTwo 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 heat-treated 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°C) to examine the relationships between the deflection and the load in the bending of wires.

RESULTSAfter DERHT treatment, the plateau in the force-deflection curve of superelastic Ni-Ti wires and heat-activated 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) N to (4.33 ± 0.07), (4.07 ± 0.05), (4.52 ± 0.08), (3.27 ± 0.15) N respectively.

CONCLUSIONSDERHT 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.

Dental Stress Analysis ; Elasticity ; Hot Temperature ; Materials Testing ; Nickel ; chemistry ; Orthodontic Wires ; Stress, Mechanical ; Titanium ; chemistry

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 treat the patients with anterior spaces caused by periodontal diseases with aligners and evaluate the periodontal conditions before and after treatment.

METHODSSeven patients with anterior spaces ranged from 3.0 to 4.5 mm were randomly selected. All the patients were treated with aligner technique to close the spaces. Bleeding on probing (BOP) and probing depth (PD) were measured before treatment, 1 month, 3 months and 6 months after treatment. The CEJ-ABC distance was evaluated before treatment, 1 month, and 6 months after treatment.

RESULTSNo significant differences were found in periodontal evaluation and the CEJ-ABC distance between any two evaluated stages.

CONCLUSIONSThe aligners could be used in patients with anterior spaces caused by periodontal diseases. No periodontal tissue damages were found during the observation period.

Adult ; Diastema ; etiology ; therapy ; Female ; Humans ; Male ; Orthodontic Appliances ; Periodontal Diseases ; complications

OBJECTIVETo analyze the relationships between MRI image changes of lateral pterygoid muscle (LPM), disc position and condylar mobility.

METHODSTwenty Class II patients were chosen and MRI images of LPM were taken. The relationships between MRI image changes of LPM, disc position and condylar mobility were analyzed.

RESULTSThe rate of MRI image changes of LPM in Class II patients was about 45%. No significant correlations were found between MRI image changes of LPM, condylar mobility and disc position.

CONCLUSIONSMRI image changes of LPM in Class II patients was common but no significant correlations were found between MRI image changes of LPM, condylar mobility and disc position.

Child ; Female ; Humans ; Magnetic Resonance Imaging ; Male ; Malocclusion, Angle Class II ; pathology ; physiopathology ; Pterygoid Muscles ; pathology ; Range of Motion, Articular ; Temporomandibular Joint ; physiopathology

OBJECTIVETo investigate the relationship between condyle movement and temporomandibular disorders (TMD) in patients with Class II division 1 malocclusion.

METHODSTwenty patients (from 11 to 12 years old) with Class II division 1 malocclusion before treatment were collected. Computer aided diagnosis axiograph (CADIAX) and magnetic resonance images (MRI) were used to analyze the condyle movement between disc displacement and normal groups.

RESULTSThe sensitive values were found in open/close process in patients with disc displacement: Y [Left: (0.32 +/- 0.10) mm, Right: (-0.91 +/- 0.49) mm ], Z [Left: (4.20 +/- 0.70) mm, Right: (3.44 +/- 0.21) mm], sagittal condylar inclination (SCI) [Left: (32.48 +/- 7.70) degrees , Right: (33.47 +/- 12.60) degrees ] and horizontal condylar inclination (TCI) [Left: (-2.60 +/- 2.02) degrees , R: (-9.23 +/- 5.58) degrees ], and those items showed significant difference between two groups.

CONCLUSIONSThe side shift of condyle movement in maximum open/close process might be the inducement of disc displacement. It was revealed that the changes in condyle movement could give useful information in early stage of functional treatment.

Child ; Diagnosis, Computer-Assisted ; instrumentation ; Female ; Humans ; Jaw Relation Record ; Male ; Malocclusion, Angle Class II ; complications ; physiopathology ; Mandibular Condyle ; pathology ; physiopathology ; Movement ; Temporomandibular Joint Disc ; pathology ; Temporomandibular Joint Disorders ; etiology ; pathology