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??Objective??To evaluate the effect of articular disc repositioning combined with orthodontic functional appliance in the treatment of juvenile bilateral temporomandibular joint ??TMJ??anterior disc displacement??ADD?? and  skeletal class ??malocclusion. Methods??Fourteen juvenile patients with bilateral TMJ ADD and skeletal class ?? malocclusion were selected from March 2016 to March 2018 in the Department of Oral Surgery??Ninth People’s Hospital??Shanghai Jiao Tong University School of Medicine. Magnetic resonance imaging ??MRI?? and cephalometric radiographs before surgery and  follow-ups were performed for all patients. Condylar height and relevant cephalometric radiographs were measured and compared by statistical analysis. Results??Compared with pre-surgery??MRI showed the condylar height increased ??1.74±0.98??mm during follow-ups after surgery ??P??0.001??. New generated bone was observed on all condyles. About 84.61% of the new bone formed at superior and posterior-anterior surface. Cephalometric radiographs showed that SNB increased ??1.83±1.56??°??P??0.001????pogonion position ??pog-G?? moved ??2.18±3.13??mm ??P = 0.028?? forward and incisor overjet decreased ??3.55 ± 1.86??mm ??P??0.001????whereas no significant changes were found in SNA??Sn - G Vert??Y-Axis??U1 - SN??IMPA ??L1-MP?? or U1-L1 ??P > 0.05??. Conclusion??Articular disc repositioning combined with postoperative orthodontic functional appliances can effectively promote condylar growth and reduce oral-maxillofacial deformities in juvenile patients with bilateral  TMJ ADD and skeletal class??malocclusion.     

Incidence of temporomandibular joint clicking in adolescents with and without unilateral posterior cross‐bite: a 10‐year follow‐up study

Among different malocclusions, posterior cross‐bite is thought to have a strong impact on the correct functioning of the masticatory system. The association between unilateral posterior cross‐bite (UPCB) and temporomandibular joint (TMJ) clicking, however, remains still controversial. The aim of this study was to investigate whether the presence of UCPB during early adolescence increases the risk of reporting TMJ clicking after a long‐term follow‐up. A longitudinal survey design was carried out in a group of 12‐year‐old young adolescents, who were examined at baseline for TMJ clicking sounds and unilateral posterior cross‐bite. After 10 years, 519 subjects could be reached by a telephone survey. Standardised questions were used to collect self‐reported TMJ sounds and to determine whether participants had received an orthodontic treatment. Logistic regression analysis revealed a significant association between unilateral posterior cross‐bite and subjectively reported TMJ clicking (odds ratio = 6·0; 95% confidence limits = 3·4–10·8; P < 0·0001). The incidence of TMJ clicking was 12%. At a ten‐year follow‐up, self‐reports of TMJ clicking were significantly associated with the presence of UPCB at baseline, but not with the report of having received an orthodontic treatment. Within the limitation of this study, the presence of unilateral posterior cross‐bite in young adolescents may increase the risk of reporting TMJ sounds at a 10‐year follow‐up. The provision of an orthodontic treatment, however, does not appear to reduce the risk of reporting TMJ sounds.     

Unbalanced lateral mandibular deviation associated with TMJ sound as a sign in TMJ disc dysfunction diagnosis

The aim was to study the characteristics of lateral mandibular horizontal deviations during opening–closing movements and their association with TMJ sounds of the clicking type. Subjects were 28 healthy volunteers and 38 patients diagnosed with MRI imaging as having TMJ disc dysfunction, 22 with disc displacement without (DD) and 16 as having disc displacement with reduction (DDR). TMJ sounds were recorded with miniature microphones placed in the ear canals, and jaw movements were documented with a kinesiograph. A sign, unbalanced lateral deviation (ubd) was defined as a rapid, short duration, change in jaw movement direction from, and back to, a smooth deviation path in the horizontal plane. The hypotheses were that degrees of maximal deviations, proportions of unbalanced deviation (ubd) and such deviation associated with TMJ sounds (ubdS), differ between healthy subjects and patients with DD or DDR. Comparisons between groups were made using one‐way anova and chi‐square analysis, as appropriate. No differences were found between groups regarding degree of lateral deviation per se. The proportions of ubd and ubdS were significantly higher in patients with DDR than in healthy subjects and than in patients with DD (P < 0·001), but no such differences were found between healthy subjects and patients with DD. For prediction of DDR, the sensitivity and specificity of the sign ubdS were found to be 68·8% and 89·3%, respectively. For the sign ubd, they were 100·0% and 64·3%. This indicates that the sign ubdS has diagnostic value in screening for DDR.     

Non-Rigid Image Registration Based Strain Estimator for Intravascular Ultrasound Elastography

Intravascular ultrasound elastography (IVUSe) could improve the diagnosis of cardiovascular disease by revealing vulnerable plaques through their mechanical tissue properties. To improve the performance of IVUSe, we developed and implemented a non-rigid image-registration method to visualize the radial and circumferential component of strain within vascular tissues. We evaluated the algorithm's performance with four initialization schemes using simulated and experimentally acquired ultrasound images. Applying the registration method to radio-frequency (RF) echo frames improved the accuracy of displacements compared to when B-mode images were employed. However, strain elastograms measured from RF echo frames produce erroneous results when both the zero-initialization method and the mesh-refinement scheme were employed. For most strain levels, the cross-correlation-initialization method produced the best performance. The simulation study predicted that elastograms obtained from vessels with average strains in the range of 3%–5% should have high elastographic signal-to-noise ratio (SNRe)–on the order of 4.5 and 7.5 for the radial and circumferential components of strain, respectively. The preliminary in vivo validation study (phantom and an atherosclerotic rabbit) demonstrated that the non-rigid registration method could produce useful radial and circumferential strain elastograms under realistic physiologic conditions. The results of this investigation were sufficiently encouraging to warrant a more comprehensive in vivo validation.     

Ultrasound can Modulate Neuronal Development: Impact on Neurite Growth and Cell Body Morphology

Neuronal development is known to be a dynamic process that can be modulated by presenting guidance cues to neuronal cells. We show that ultrasound, when applied at pulsed settings and with intensities slightly greater than clinical diagnosis levels, can potentially act as a repulsive cue for modulating neuronal growth dynamics. Using differentiated Neuro-2a cells as the model, we have examined in vitro how neuronal development can change during and after exposure to 1-MHz ultrasound for different acoustic settings. Neurite retraction and cell body shrinkage were found in neuronal cells over a 10-min exposure period with 1.168 W/cm² spatial-peak, time-averaged intensity (based on 0.84 MPa peak acoustic pressure, 100-cycle pulse duration, and 500-Hz pulse repetition frequency). These effects were found to result in instances of neuronal cell body displacement. The extent of the effects was dependent on acoustic intensity, with peak acoustic pressure being a more important contributing factor compared with pulse duration. The morphological changes were found to be non-destructive, in that post-exposure neurite outgrowth and neuritogenesis were respectively observed in neurite-bearing and neurite-less neuronal cells. Our results also showed that mechanotransduction might be involved in mediating ultrasound-neuron interactions, as the morphological changes were suppressed if stretch-activated ion channels were blocked or if calcium messenger ions were chelated. Overall, these findings suggest that ultrasound can potentially influence how neuronal cells develop through modifying their cytomechanical characteristics.     

Preparation of Nanoparticles by Solvent Displacement Using a Novel Recirculation System

Submicron colloidal suspensions of poly(ε-caprolactone) (PCL) were prepared by the solvent displacement method, using either the conventional form or a new recirculation device. In the latter case, a process that allows the recirculation of the aqueous phase into a device, providing a continuous flow, is proposed. The influence of the organic solution injection rate and polymer concentration on mean particle size and process yield were studied for both methods. The recirculation rate was also analyzed for the recirculation system. Nanoparticles (NPs) showed mean sizes that ranged from 156 to 381. The smallest particles were obtained when recirculation rate, injection rate and polymer concentration were maximized but at the expense of the yield. The only acceptable yields (83–96%) were obtained at the lowest PCL concentration (2.5% w/v). ANOVA tests (α = 0.05) showed that the variables implicated in the recirculation system significantly affected the mean particle size and the process yield. The entrapment efficiencies of NPs prepared by the conventional method were not significantly different (α = 0.05) from those obtained by the recirculation system.     

胶原酶化学髓核溶解术机制的再研究

目的:研究胶原酶盘内注射对山羊腰椎间盘突出模型的化学髓核溶解作用,重新评估化学髓核溶解术的机制。方法:胶原酶注射前10周,通过手术损伤椎间盘前外侧纤维环诱发椎间盘突出和退变,并经MRI证实。胶原酶注射后1天、1周、2周、4周、12周观察X线片上椎间盘高度指数、椎间盘的组织学等变化。结果:胶原酶对正常和退变椎间盘髓核组织具有类似的溶解作用。胶原酶盘内注射后在突出模型椎间盘中央和髓核突出部位均出现溶解空腔,终板破坏轻;而对正常椎间盘溶解部位在椎间盘髓核和内层纤维环,并严重破坏终板。结论:盘内注射胶原酶能有效溶解山羊突出模型椎间盘的中央和突出部位髓核组织。胶原酶注射后12周,退变间盘基质出现再生能力。     

腰椎间盘突出症患者手术疗效不佳的因素分析

目的手术是治疗腰椎间盘突出症的一个重要方法,探讨腰椎间盘突出症手术疗效不佳需再次手术的原因。方法通过19例需再次手术的腰椎间盘突出症病例进行回顾性研究,结合文献找出再次手术的原因。结果再次手术的原因主要是术前诊断及定位错误、术后血肿压迫、椎间盘再次突出、对侧隐窝狭窄认识不足、椎管内瘢痕增生粘连、感染等。结论术前准备充分,术中操作规范,术后针对不同情况积极预防是避免再次手术的关键。