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Malocclusion is an oral disease with a high prevalence. The goal of orthodontic treatment is health, aesthetics, function and stability. The transmission straight wire appliance and technique is an innovative orthodontic system with independent intellectual property rights invented by Professor Jiuxiang Lin's team based on decades of clinical experience, which provides a new solution for the non-surgical correction of skeletal malocclusions, especially class Ⅲ malocclusion, and it is also a good carrier for the implementation of the concept of healthy orthodontics. Due to the lack of guidelines, how to implement standardized application of transmission straight wire technique remains a problem to be solved. This technical specification was formed by combining the guidance from Professor Jiuxiang Lin and joint revision by a number of authoritative experts from the Orthodontic Special Committee, Chinese Stomatological Association, with reference to relevant literatures, and combined with abundant clinical experience of many experts. This specification aims to provide reference to standardize the clinical application of transmission straight wire technique, so as to reduce the risk and complications, and finally to improve the clinical application level of this technique.

Dentition defects damage the integrity of the dental arch, affecting smile esthetics and oral function. Compared to restorative treatment, pre-restoration orthodontic treatment overcomes the limitations of a single method, effectively avoiding excessive wear of natural teeth, reducing the number of units for restorative production to a certain extent, and potentially improving facial shape and occlusal relationship, which maximizes the therapeutic effect. This article explores the key points of pre-restoration orthodontic treatment for different types of dentition defects in terms of malocclusion manifestations, treatment objectives, treatment methods, and maintenance recommendations from the perspective of combined orthodontic restoration treatment.

Objective: To construct SD rat immortalized dental follicle cells (rDFC) induced by simian virus 40 large tumor antigen (SV40Tag) gene to provide a reliable cell source for periodontal tissue engineering research., Methods: The rDFC was isolated by tissue mass method combined with enzyme digestion method and evaluated by immunohistochemistry. Cell293 were transfected with plasmid pSSR69/pAmpho containing SV40Tag gene by mediating liposome. Normal rDFC were infected with virus-contained supernate and the successfully transfected cell lines were screened with hygromycin, and positive clones were cultured. While non-transfected cells served as negative controls, the cell morphology was observed, the proliferation characteristics was evaluated by calculating cell population. The expression of SV40Tag gene and telomerase in cells was detected by reverse transcription polymerase chain reaction (RT-PCR) and Western blotting respectively. The biological property of immortalized rDFC was assessed with calculating formation rate of flat cloning, soft agar colony formation test and tumor-forming test., Results: Morphology of immortalized rDFC was not different from that of normal rDFC. The RT-PCR results of SV40Tag revealed amplification band at 357 bp, while no band was seen in the normal cells. The expression of telomerase in immortalized rDFC was higher than that in normal rDFC. The two groups had no significant difference in growth curves, but the immortalized rDFC exhibited stronger proliferative activity. No significant differences of formation rate in flat cloning were observed between the immortalized rDFC [34% (33/96)] and normal rDFC at passage four [22% (21/96)] (χ(2) = 3.71, P > 0.05). No cell cloning was seen in soft agar and the tumor formation was not observed in nude mice., Conclusions: The rDFC induced by SV40Tag gene could be cultured and passaged in vitro, which retained the stable proliferation and differentiation characteristics and could be used for periodontal tissue engineering research.

Objective: To evaluate the effects of low intensity pulsed ultrasound (LIPUS) combined with guided tissue regeneration (GTR) for the repair of the periodontal fenestration defect at the canines in Beagle dogs., Methods: Four Beagle dogs were used for establishing the periodontal fenestration defect. Sixteen canines of four Beagle dogs were simple randomly assigned into experimental group 1 [LIPUS (60 mW/cm(2), 20 min/d) irradiation + GTR + the periodontal fenestration defect], experimental group 2 [LIPUS (60 mW/cm(2), 20 min/d) irradiation + the periodontal fenestration defect], experimental group 3 (GTR + the periodontal fenestration defect) and control group (the periodontal fenestration defect). Experiments conducted 28 d. The temperature of the gingive's surface of each group was tested every 14 days (analyzed by Wilcoxon rank sum test with SPSS 13.0). The demineralized bone tissue slices of the periodontal fenestration were obtained for histologic staining after 4 weeks treatment., Results: Clinically all the treatment groups healed well. The change of gingive's surface temperature [M(Q)] before and after LIPUS irradiating were: 0.225 (0.463)°C (experimental group 1), 0.265 (0.133)°C (experimental group 2), 0.090 (0.115)°C (experimental group 3); -0.175 (0.370)°C (control group). The P value of experimental group 1 and 2 with pre-and post-treatment each time were both 0.027. Histology of the demineralized bone tissue revealed that in experimental group 1, the bone defect was filled with fresh bone-like tissues, proliferatively active osteoblasts and newly formed cementum-like tissues along the defect surface. In experimental group 3, there were more new cementum- and bone-like tissues than in experimental group 2 and control group. In experimental group 2, the new bone collagen was more mature than in experimental group 3 and control group. In control group, there was less growth of new cementum along the notch, and the new bone collagen was immature., Conclusions: LIPUS combined with GTR may have the potential of promoting the repair of periodontal fenestration defect.

Objective: To construct a three-dimensional finite element model of mandible and to analyze the stress distribution in mandible advanced with Forsus., Methods: One growing patient with mandibular retrusion was selected. After leveling and aligning with MBT (Mclaughlin Bennett Treriri) straight-wire appliance to achieve the request of forsus with the spiral CT, a three-dimensional finite element model was constructed and the stress distribution in mandible after advancing at 1 second, 15 seconds and 300 seconds was analyzed., Results: The three-dimensional finite element model included MBT straight-wire appliance. The stress concentration areas were located in the front side of the condylar process, the sigmoid notch and mandibular molar areas at 15 seconds and 300 seconds after mandibular advancement. The maximum stress values were 34.47 MPa and 34.45 MPa, respectively. With the extension of loading time, the largest displacement increased from 3.30 x 10(-2) mm to 1.15 mm and the region of the largest displacement extended backwards along the body of mandible. However, the displacement of condyle reduced from 1.65 x 10(-2) mm at 1 second to 3.27 x 10(-5) mm at 300 seconds after mandibular advancement., Conclusions: The three-dimensional finite element model considered the viscoelasticity and viscoelasticity of mandibular. The result suggested that the stress distribution in the mandible gradually became stable after the application of Forsus and the appliance caused downward and forward mandibular modification.

Objective: To assess changes in prevalence and degree of dental fluorosis in individuals born before and after the introduction of water with 1.2 mg/L fluoride instead of water with 2.0-10.0 mg/L fluoride previously used in Da Li County in China., Methods: The students (n = 291) were divided into 2 groups. The dental fluorosis was scored according to Dean's classification. The statistical analysis was performed by t-test and chi(2) tests., Results: The prevalence of dental fluorosis was significantly lower in the group of the students drinking water from the new well (group 1) as compared to the group of the students drinking the old water (group 2), i.e. 48.8% versus 87.2% (P < 0.01). The percentage of moderate to very severe fluorosis was 13.9% and 0 in group 1 as compared to 32.0% and 8.8% in group 2. The fluorosis community index (FCI), defined by Dean, in group 1 and 2 was medium (1.01) and marked (2.12) respectively., Conclusions: The results showed that: (1) The prevalence of dental fluorosis was significantly lowered by the new source of drinking water. (2) Drinking water, even with 1.2 mg/L fluoride, may cause dental fluorosis during the period of tooth mineralization.