应用组织工程技术构建角膜基质组织

目的应用角膜基质细胞和聚羟基乙酸(PGA)多聚体复合物构建角膜基质,为组织工程技术构建角膜提供依据。方法将培养后的角膜基质细胞-生物材料复合物植入balb/c裸鼠皮下。6周后,对新生组织进行组织学和透射电镜检测,并测定胶原纤维直径。结果石蜡包埋切片显示新生角膜组织具有似正常角膜基质层波浪交叉编织结构。组织工程化的角膜基质胶原纤维直径(27.7±6.2)nm,与正常角膜基质胶原纤维直径相似。结论组织工程技术重建的角膜基质已经具备角膜基质层组织形态学和组织学特征。     

胶原壳聚糖医用海绵疗效特征探讨

AIM: To investigate the hemostaaia effect of hemostasis sponge of collagen and chitosan compound invitro and in vivo. METHODS: The hemostasis sponge of collagen and chitosan compound was made by mixing collegen I ertracted by enzymelytic methods and crosslinked by glutaric dialdeiyde and then lyophilized. The New Zealand rabbit were created with a 1 cm×1 cm wound in the center artery of the ear. The center artery of the ear were transected and record the hemostasis time since pressured with hemostasis sponge of collagen and chitosan compound and observe its effects. In other experiements, 1 cm×1 cm bleeding wound were established in the liver of the rabbit Then pressured with hemostasis sponge of collagen and chitosan compound on the wounds and record the hemostasis time; The four comer of the hemostasis sponge of collagen and chitosan compound were sutured to investigate the absorption situation with the control of gelatin treated with same procedures. RESULTS: The bleeding time using hemostasis spon     

Readability of printed educational materials used to inform potential and actual ostomates

• ? This paper is primarily concerned with the use of readability formulas to determine the reading ease of printed education materials (PEMs) given to ostomy patients. Whilst the particular clinical focus is stoma care nursing, the content is relevant to all nurses who use printed text to inform their patients. PEMs have significant advantages in conveying information compared with verbal presentations alone.
• ? Methods to calculate readability using the Flesch, FOG and SMOG readability formulas are described. Presentation factors that affect readability are briefly reviewed, including use of ‘white space’, font size and paper colour. The problem of functional illiteracy and the need for indirect assessment of patient literacy are discussed.
• ? PEMs in use are often found to be difficult to read. Stress is identified as a potential factor in further reducing a patient's ability to deal with information.
• ? Three commercially available PEMs are evaluated for ease of reading and their score on the FOG index indicates that only about 40% of the UK population would understand them.
• ? Nurses are advised to evaluate the readability of their PEMs and to assess indirectly the literacy of their patients, so that they can more sensitively match PEMs to patient ability and need.

     

Medical use of cannabis: an addiction medicine perspective

The use of cannabis for medical purposes, evident throughout history, has become a topic of increasing interest. Yet on the present medical evidence, cannabis‐based treatments will only be appropriate for a small number of people in specific circumstances. Experience with cannabis as a recreational drug, and with use of psychoactive drugs that are prescribed and abused, should inform harm reduction in the context of medical cannabis.     

Long‐Term Stability of Root Coverage by Coronally Advanced Flap Procedures

Background: This study compared 6‐month and 3‐year outcomes for root coverage (RC) by coronally advanced flap (CAF) procedures in localized gingival recessions. Methods: Two centers, that had participated in a 6‐month multinational multicenter randomized clinical trial (RCT), followed up 18 patients with 36 Miller Class I and II defects that had been treated in a split‐mouth design with CAF procedures or CAF + xenogeneic collagen matrix (CMX). Percentage of RC, complete root coverage (CRC), width, and thickness of keratinized tissue were assessed by the same masked examiners as after the 6‐month RCT. Results: There was a high correlation between 6‐month and 3‐year RC outcomes for both CAF procedures. Mean RC after CAF + CMX amounted to 89.9% after 6 months and 91.7% after 3 years (Pearson’s correlation: 0.91). Corresponding values for CAF were 83.7% versus 82.8% (Pearson’s correlation: 0.94). Likewise, CRC was stable with 61%/61% for CAF + CMX and 39%/39% for CAF after 6 months/3 years, respectively. Conclusions: In this 3‐year follow‐up of a subgroup of patients from a previous 6‐month RCT, there was a high correlation between the results for RC after 6 months and 3 years, indicating their stability. These data suggest that 6‐month outcomes may be useful to predict long‐term outcomes in CAF procedures with or without additional use of CMX.     

Effects of core-to-dentin thickness ratio on the biaxial flexural strength,reliability, and fracture mode of bilayered materials of zirconia core (Y-TZP) and veneer indirect composite resins

Statement of problem

Indirect composite resins (ICR) are promising alternatives as veneering materials for zirconia frameworks. The effects of core-to-dentin thickness ratio (C/Dtr) on the mechanical property of bilayered veneer ICR/yttria-tetragonal zirconia polycrystalline (Y-TZP) core disks have not been previously studied.

Bacterial Contamination of Endodontic Materials before and after Clinical Storage

Introduction

The aim of this study was to evaluate the bacterial contamination in endodontic consumables (gutta-percha points, rubber dams, paper mixing pads, caulking agents, and endodontic instrument sponges [EISs]) before and after clinical use and storage.

Advances in Nanotechnology for Restorative Dentistry

Rationalizing has become a new trend in the world of science and technology. Nanotechnology has ascended to become one of the most favorable technologies, and one which will change the application of materials in different fields. The quality of dental biomaterials has been improved by the emergence of nanotechnology. This technology manufactures materials with much better properties or by improving the properties of existing materials. The science of nanotechnology has become the most popular area of research, currently covering a broad range of applications in dentistry. This review describes the basic concept of nanomaterials, recent innovations in nanomaterials and their applications in restorative dentistry. Advances in nanotechnologies are paving the future of dentistry, and there are a plenty of hopes placed on nanomaterials in terms of improving the health care of dental patients.     

Combined Characterization of the Time Response of Impression Materials via Traditional and FTIR Measurements

We investigated the temporal response of four dental impression materials, namely three siloxanes (Imprint 4, Flexitime, Aquasil) and one polyether (Impregum). The null hypothesis was that the nominal working times are confirmed by instrumental laboratory tests. We also aimed to identify alternative techniques with strong physical-chemical background for the assessment of temporal response. Traditional characterization was carried out by shark fin test device and durometer at both ambient and body temperature. Additionally, Fourier-transform infrared spectroscopy was performed at room temperature. From shark fin height and Shore hardness versus time the working time and the setting time of the materials were evaluated, respectively. These were in reasonable agreement with the nominal values, except for Impregum, which showed longer working time. Spectroscopy confirmed the different character of the two types of materials, and provided for Imprint 4 and Aquasil an independent evaluation of both evolution times, consistent with the results of the other techniques. Shark fin test and durometer measurements showed deviations in setting time, low sensitivity to temperature for Flexitime, and longer working time at higher temperature for Impregum. Deviations of working time appear in operating conditions from what specified by the manufacturers. Fourier-transform infrared spectroscopy can provide insight in the correlation between material properties and their composition and structure.