The relationship between transverse plane leg rotation and transverse plane motion at the knee and hip during normal walking

The purpose of this study was to test the clinical hypothesis that the magnitude and temporal characteristics of rearfoot complex motion are closely correlated with those of the transverse plane motion at the knee and hip. Twenty subjects underwent kinematic assessment during walking at 108 steps/minute. The transverse plane rotation of the leg relative to the foot was used to indicate rearfoot complex pronation and supination. Taking into account errors inherent in kinematic assessment involving skin mounted markers, it is unlikely that a correlation exists between the range of internal leg rotation during the contact phase and the total range of transverse plane leg rotation during gait and the corresponding values for the transverse plane motion at the knee and hip. Correlation tests were performed to assess the temporal characteristics of the motions at the joints that showed that there was no correlation between the transverse plane motion in the rearfoot complex, knee and hip. Thus the hypothesis that the magnitude and temporal characteristics of rearfoot complex motion are closely correlated with the transverse plane motion at the knee and hip was rejected.     

胃食管反流病致重度牙齿侵蚀的固定-活动联合修复

目的:探讨用固定-活动义齿联合修复,对胃食管反流病致重度牙齿侵蚀症患者进行咬合重建的临床效果。方法:对从2010年1月~2013年10月来我院就诊的10例胃食管反流病致重度牙侵蚀症患者采用诊断义齿过渡3~6个月,患者适应后再以诊断义齿为依据,采用固定-活动联合修复行咬合重建。分别于修复后3个月、6个月、1年、2年、3年复查。复查内容:修复体完整性、咬合稳定性、美观度、患者使用满意度。结果:整个随访期间,10例咬合重建患者面部外形改善,咀嚼功能恢复良好,患者对义齿的美观及舒适性均较为满意,配合用药后食管反流症状基本消失。结论:用固定-活动义齿联合修复,进行牙合重建能恢复患者美观,提高咀嚼功能同时后期维护简便。     

Effects of experimental occlusal interference on body posture: an optoelectronic stereophotogrammetric analysis

In recent years, there has been increasing interest in the relationship between dental occlusion and body posture both among people and in scientific literature. The aim of the present longitudinal study is to investigate the effects of an experimental occlusal interference on body posture by means of a force platform and an optoelectronic stereophotogrammetric analysis. An occlusal interference of a 0‐ to 2‐mm‐thick glass composite was prepared to disturb the intercuspal position while not creating interference during lateral or protrusive mandibular excursions. Frontal and sagittal kinematic parameters, dynamic gait measurements and superficial electromyographic (SEMG) activity of head and neck muscles were performed on 12 healthy subjects. Measurements were taken 10 days before the application of the occlusal interference, and then immediately before the application, the day after it, and at a distance of 7 and 14 days under four different exteroceptive conditions. The outcomes of this study show that an occlusal interference does not modify significantly over time static and dynamic parameters of body posture under different exteroceptive conditions. It has a minimal influence only on the frontal kinematic parameters related to mandibular position, and it induces a transient increase of the activity of masticatory muscles. In this study, the experimental occlusal interference did not significantly influence the body posture during a 14‐day follow‐up period.     

The importance of the mesofascial interface in complete mesocolic excision

Complete mesocolic excision (CME) with Central Vascular Ligation (CVL) is progressively gaining acceptance as the most updated surgical treatment in the multimodal management of colonic cancer. The concept is based on excision of the affected organ with its related primitive dorsal mesenterium as an intact package to maximize local clearance, and high tie ligation to boost regional control, translating the original concept of Total Mesorectal Excision proposed by Heald for rectal cancer. Aim of this review is to analyze the modern concept of the mesenteric organ, with particular regard to the interfaces between its single components and the importance of the meso-fascial interface as the correct plane of separation.The integrity of the mesocolon excised along the meso-fascial interface (meso-fascial separation) prevents any breach of its surface and underlying structures, preserving the radial margin and the complex network of the meso-structure, avoiding any spillage of neoplastic cells within the surgical field. Central Vascular ligation allows for the most effective harvesting of lymph nodes, particularly of the apical ones, whose removal appears to be crucial in optimizing regional control.A surgical plane developed along the meso-fascial interface, coupled with high tie ligation, yields higher quality of surgical specimen, with better oncologic outcome in terms of local recurrence rate, disease-free and overall survival.     

Accuracy of two midsagittal planes in three-dimensional analysis and their measurement in patients with skeletal mandibular deviation: a comparative study

Our aim was to evaluate the accuracy of two midsagittal planes (MSP) to provide a better reference plane for studying the 3-dimensional structural symmetry in patients with skeletal mandibular deviation. Thirty adult patients with facial asymmetry were admitted to the Department of Orthodontics, Hospital of Stomatology, between January 2015 and 2017. The DICOM data were collected and reconstructed using ProPlan CMF^® 2.0 (Materialise). Two sets of reference planes were set up. In the orbital margin plane group, the plane crossing the nasion (N) point and perpendicular to the frontozygomatic (FZ) suture line was used as the MSP. In the skull base plane group, the MSP was established using the sella turcica (S), N, and basion (Ba). The distances from the craniofacial skeletal and soft tissue midline landmarks to the two MSP were separately measured, and the significance of differences between measurements corresponding to two reference planes were assessed using the paired t test. Except for the posterior nasal spine (PNS)-MSP, the distances from other soft and hard tissue landmarks to the MSP in the orbital margin plane group were significantly shorter than those in the skull base plane group. In the 3-dimensional measurement analysis, the skeletal and soft tissue anatomical midline landmarks were closer to the MSP in the orbital margin plane group. The MSP crossing point N, perpendicular to the FZ suture line, was more accurate and suitable.     

Evaluation of masticatory activity during unilateral single tooth clenching using muscle functional magnetic resonance imaging

Masticatory muscle activity during teeth clenching is affected by occlusal pattern. However, few studies have performed simultaneous evaluation of all masticatory activities during teeth clenching under various occlusal conditions. The aim of this study was to use muscle functional magnetic resonance imaging (mfMRI) to evaluate the effects of changes in occlusal point on masticatory activity during single tooth clenching. Changes in mean proton transverse relaxation time (?T2) as an index of activity in all masticatory muscles during left unilateral clenching at the first molar or first premolar for 1 min were examined in nine healthy volunteers. Bite force was maintained at 40% of the maximum voluntary clenching force. The ?T2 values of the masseter and lateral pterygoid muscles were analysed separately for superficial and deep layers, and for superior and inferior heads. The ?T2 values for the ipsilateral deep masseter were significantly lower, and for the superior head of the ipsilateral lateral pterygoid muscles were significantly higher, after left first premolar clenching compared to left first molar clenching. These results quantitatively demonstrate a significant increase in activity of the superior head of the ipsilateral lateral pterygoid muscle and a significant decrease in activity of the ipsilateral deep masseter muscle with forward displacement of the occlusal contact point during unilateral tooth clenching.     

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??During the period of growth and development in children??the normal occlusion plays an important role in the development of children’s oral maxillofacial region. Nevertheless??some systemic developmental diseases will result in abnormalities in teeth??dentition??mandible and maxilla??which may lead to different kinds of occlusal problems. In this paper??we summarize several systemic developmental diseases complicated with occlusal abnormalities and hope that it will be helpful for dentists in clinical work.     

Clinical assessment of enamel wear caused by monolithic zirconia crowns

The purpose of this study was to measure enamel wear caused by antagonistic monolithic zirconia crowns and to compare this with enamel wear caused by contralateral natural antagonists. Twenty monolithic zirconia full molar crowns were placed in 20 patients. Patients with high activity of the masseter muscle at night (bruxism) were excluded. For analysis of wear, vinylpolysiloxane impressions were prepared after crown incorporation and at 6‐, 12‐, and 24‐month follow‐up. Wear of the occlusal contact areas of the crowns, of their natural antagonists, and of two contralateral natural antagonists (control teeth) was measured by use of plaster replicas and a 3D laser‐scanning device. Differences of wear between the zirconia crown antagonists and the control teeth were investigated by means of two‐sided paired Student's t‐tests and linear regression analysis. After 2 years, mean vertical loss was 46 μm for enamel opposed to zirconia, 19–26 μm for contralateral control teeth and 14 μm for zirconia crowns. Maximum vertical loss was 151 μm for enamel opposed to zirconia, 75–115 μm for control teeth and 60 μm for zirconia crowns. Statistical analysis revealed significant differences between wear of enamel by zirconia‐opposed teeth and by control teeth. Gender, which significantly affected wear, was identified as a possible confounder. Monolithic zirconia crowns generated more wear of opposed enamel than did natural teeth. Because of the greater wear caused by other dental ceramics, the use of monolithic zirconia crowns may be justified.