[Effect of micro-implant assisted rapid palatal expansion in patients with different radiographic stages of mid-palatal suture maturation].

Objective: To evaluate the effect of micro-implant assisted rapid palatal expansion (MARPE) in patients with different radiographic stages of midpalatal suture maturation. Methods: Twenty-eight patients [7 males and 21 females; age (15.5±5.5) years] with maxillary transverse deficiency were selected in the Department of Orthodontics, Hospital of Stomatology, Jilin University from February 2017 to October 2019. According to the fusion of the midpalatal suture, the patients were divided into two groups: 10 patients [3 males and 7 females; age (19.9±6.9) years] were in fusion group and 18 patients [4 males and 14 females; age (13.0±2.4) years] were in non-fusion group. Each patient had cone-beam CT (CBCT) images taken immediately after the placement of micro-implants (T1) and the completion of maxillary expansion (T2). The CBCT images were analyzed using the Dolphin Imaging software to evaluate the amount of midpalatal expansion and the percentages of bony expansion, etc. Statistical analysis was carried out to compare the two groups. Results: After MARPE treatment, the amount of sutural expansion in fusion group was (3.23±1.45) mm while that in non-fusion group was (4.97±1.47) mm (P<0.05). There was a statistically significant difference in the percentages of bony expansion efficiency between the non-fusion group (71±20)% and the fusion group (46±18)% (P<0.05). Conclusions: Bony expansion efficiency was affacted by the radiographic stages of midpalatal suture maturation.

Preoperative scar perception study comparing 'scarless' in the neck endoscopic thyroidectomy with open thyroidectomy: a cross-sectional study.

INTRODUCTION: Open thyroidectomy is the most common approach to thyroid surgery. However, 'scarless' (in the neck) endoscopic thyroidectomy, consisting of endoscopic and robotic surgery, is progressively being adopted for its perceived cosmetic benefits. This study aims to determine the patient's preferred surgical approach and to identify the factors that influence their decision. MATERIALS AND METHODS: A pilot study consisting of 100 patients with a surgical thyroid disorder were prospectively recruited from a single tertiary centre. An interviewer-administered survey was conducted. Demographic, socioeconomic status, scar perception and an adapted body image scale were evaluated to identify factors that shaped the patient's perception of the surgical approach. RESULTS: The mean age of participants was 54.5 ± 13.0 years; 72% were women and 87% Chinese. Of the 100 patients, 75 patients considered scarless endoscopic thyroidectomy as their preferred surgical approach while 25 patients opted for open thyroid surgery. Improvement in scar perception score between scarless endoscopic thyroidectomy and open thyroid surgery is associated with an increased willingness to choose scarless endoscopic thyroidectomy. The mean body image scale score was 6.9 ± 2.8, indicating no statistical difference between the surgical approaches. On multivariate analysis, improvement in scar perception score (odds ratio 3.38, 95% confidence interval 1.11-10.29) and having surgeon recommendation (odds ratio 6.38, 95% confidence interval 1.80-22.63) were independently associated with interest in scarless endoscopic thyroidectomy. CONCLUSION: Patients interest in undergoing scarless endoscopic thyroidectomy is driven by improved scar perception and surgeon's recommendation compared with open thyroid surgery.

[Study on the effect of curculigoside on osteoporosis].

Objective: To investigate the regulation of curculigoside on osteogenic differentiation of MG63 and the protective effect on osteoporosis model mice. Methods: The effects of curculigoside on the survival rate of dexamethasone or H(2)O(2) treated MG63 were detected by methyl thiazolyl tetrazolium (MTT). The specimens were divided into six groups: blank control group, blank administration group, model group (dexamethasone or H(2)O(2) treatment group), low dose group (dexamethasone or H(2)O(2)+1.0 µmol/L curculigoside), medium dose group (dexamethasone or H(2)O(2)+2.5 µmol/L curculigoside) and high dose group (dexamethasone or H(2)O(2)+5.0 µmol/L curculigoside), the sample size of each group was 10. Western blotting was used to detect the expression of osteogenic differentiation-related proteins [type Ⅰ collagen, integrin ß1, osteoblast-specific transcription factor (Osterix), osteocalcin and osteopontin] in MG63 cells after 1, 7 and 14 days incubated with 0, 1.0, 2.5 and 5.0 µmol/L of curculigoside. The sample size for each group at each time point was six. The experimental mice were divided into 4 groups: blank group, model group (dexamethasone treatment group), curculigoside low-dose group (dexamethasone+5 mg/kg curculigoside) and high-dose group (dexamethasone+45 mg/kg curculigoside), twenty each. After treatment, the tibia of the mice in each group were subjected to sacral HE staining. The number of osteoclasts was counted, and the levels of oxidative related factors in serum were determined by enzyme-linked immunosorbent assay (ELISA). Results: The MTT results showed that compared with the blank control group [(100±3.7)%], the cell survival rate decreased to (44.1±5.7)% after treatment with dexamethasone, and the survival rate increased to (79.7±3.8)% after treatment with 5.0 µmol/L of curculigoside. The cell survival rate decreased to (59.1±4.7)% after H(2)O(2) treatment, and the survival rate increased to (80.8±3.5)% after treatment with 2.5 µmol/L of curculigoside. The results of Western blotting showed that the expression of type Ⅰ collagen and integrin ß1 in MG63 cells was significantly increased after 1.0, 2.5 and 5.0 µmol/L of curculigoside for 1, 7 and 14 days compared with 0 µmol/L of curculigo side for the same period. After increasing (P<0.05), the expression of Osterix and osteocalcin was significantly increased after 1 day of incubation (P<0.05). However, compared with 0 µmol/L curculigoside treatment, the expression of osteopontin in MG63 cells was not significantly different after incubation with 1.0, 2.5, 5.0 µmol/L of curculigoside for 7 and 14 days (P>0.05). Compared with the blank group, the number of tibia osteoclasts in the osteoporosis model group increased. In the low-dose and high-dose groups of curculigoside, the tibia cortex was more continuous and the number of osteoclasts decreased. Compared with the blank group, the activity of oxygen in the osteoporosis model group was significantly increased (P<0.05), and superoxide dimutase and catalase were significantly decreased (P<0.05). Conclusions: Curculigoside promotes the differentiation of MG63 cells by increasing the expression of osteoblast differentiation-related proteins, and has a certain therapeutic effect on dexamethasone-induced osteoporosis mice.

A Computational Study of Mechanical Performance of Bioresorbable Polymeric Stents with Design Variations.

PURPOSE: The study compared the mechanical behavior of bioresorbable polymeric stents with various designs during deployment, and investigated their fatigue performance under pulsatile blood pressure loading. METHODS: Finite element simulations have been carried out to compare the mechanical performance of four bioresorbable polymeric stents, i.e., Absorb, Elixir, Igaki-Tamai and RevaMedical, during deployment in diseased artery. Tri-folded balloon was modelled to expand the crimped stent onto the three-layered arterial wall with plaque. Cyclic diastolic-systolic pressure loading was applied to both stent and arterial wall to study fatigue behavior. RESULTS: Stents with larger U-bend and longer axial strut demonstrate more flexibility but suffer from severe dogboning and recoiling effects. Stress concentrations in the stent, as well as in the plaque and artery, are higher for stents designed with increased rigidity such as those with smaller U-bends and shorter axial struts. Simulations of fatigue deformation for Elixir stent demonstrate that the U-bends, with high stress concentrations, have a potential risk of fatigue failure under pulsatile systolic-diastolic blood pressure as opposed to the counter metallic stents which are normally free of fatigue failure. CONCLUSION: The structural behaviour of bioresorbable polymeric stent is strongly affected by its design, in terms of expansion, dogboning, recoiling and stress distribution during the deployment process.

A computational study of crimping and expansion of bioresorbable polymeric stents.

This paper studied the mechanical performance of four bioresorbable PLLA stents, i.e., Absorb, Elixir, Igaki-Tamai and RevaMedical, during crimping and expansion using the finite element method. Abaqus CAE was used to create the geometrical models for the four stents. A tri-folded balloon was created using NX software. For the stents, elastic-plastic behaviour was used, with hardening implemented by considering the increase of yield stress with the plastic strain. The tri-folded balloon was treated as linear elastic. To simulate the crimping of stents, a set of 12 rigid plates were generated around the stents with a radially enforced displacement. During crimping, the stents were compressed from a diameter of 3 mm to 1.2 mm, with the maximum stress developed at both inner and outer sides of the U-bends. During expansion, the stent inner diameter increased to 3 mm at the peak pressure and then recoiled to different final diameters after balloon deflation due to different stent designs. The maximum stress was found again at the U-bends of stents. Diameter change, recoiling effect and radial strength/stiffness were also compared for the four stents to assess the effect of design variation on stent performance. The effect of loading rate on stent deformation was also simulated by considering the time-dependent plastic behaviour of polymeric material.