Browsing by Subject "Biomaterials"

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  • Sieviläinen, Meri (Helsingfors universitet, 2016)
    This study is a review of literature on stem cell therapies such as bone tissue engineering and their safety. The main focus is on bone tissue engineering done in the neurocranium and viscerocranium with mesenchymal stem cells. Mesenchymal stem cells are considered safe and have been used in numerous clinical case studies. Still many questions are unanswered on their tumorigenic and immunogenic potential. The aim of this study was to analyze the safety of bone tissue engineering with mesenchymal stem cells and to review literature on the most used scaffolds. This study proves that more resources must be used to study the stem cell therapies and their potential risks, find out the optimal biomaterial to be used as a scaffold and to provide a more systematical analysis of all current tissue engineering data on bones. Furthermore, results should be published even of failed studies.
  • Thesleff, Tuomo; Lehtimaki, Kai; Niskakangas, Tero; Huovinen, Sanna; Mannerström, Bettina; Miettinen, Susanna; Seppänen-Kaijansinkko, Riitta; Ohman, Juha (2017)
    Several alternative techniques exist to reconstruct skull defects. The complication rate of the cranioplasty procedure is high and the search for optimal materials and techniques continues. To report long-term results of patients who have received a cranioplasty using autologous adipose-derived stem cells (ASCs) seeded on beta-tricalcium phosphate (betaTCP) granules. Between 10/2008 and 3/2010, five cranioplasties were performed (four females, one male; average age 62.0 years) using ASCs, betaTCP granules and titanium or resorbable meshes. The average defect size was 8.1 x 6.7 cm(2). Patients were followed both clinically and radiologically. The initial results were promising, with no serious complications. Nevertheless, in the long-term follow-up, three of the five patients were re-operated due to graft related problems. Two patients showed marked resorption of the graft, which led to revision surgery. One patient developed a late infection (7.3 years post-operative) that required revision surgery and removal of the graft. One patient had a successfully ossified graft, but was re-operated due to recurrence of the meningioma 2.2 years post-operatively. One patient had an uneventful clinical follow-up, and the cosmetic result is satisfactory, even though skull x-rays show hypodensity in the borders of the graft. Albeit no serious adverse events occurred, the 6-year follow-up results of the five cases are unsatisfactory. The clinical results are not superior to results achieved by conventional cranial repair methods. The use of stem cells in combination with betaTCP granules and supporting meshes in cranial defect reconstruction need to be studied further before continuing with clinical trials.
  • Hassan, Ghada Ali Mohamed Saber; Forsman, Nina; Wan, Xing; Keurulainen, Leena; Bimbo, Luis M.; Johansson, Leena-Sisko; Sipari, Nina; Yli-Kauhaluoma, Jari Tapani; Zimmermann, Ralf; Stehl, Susanne; Werner, Carsten; Saris, Per E. J.; Österberg, Monika; Moreira, Vânia M. (2019)
    The design of antimicrobial surfaces as integral parts of advanced biomaterials is nowadays a high research priority, as the accumulation of microorganisms on surfaces inflicts substantial costs on the health and industry sectors. At present, there is a growing interest in designing functional materials from polymers abundant in nature, such as cellulose, that combine sustainability with outstanding mechanical properties and economic production. There is also the need to find suitable replacements for antimicrobial silver-based agents due to environmental toxicity and spread of resistance to metal antimicrobials. Herein we report the unprecedented decoration of cellulose nanofibril (CNF) films with dehydroabietylamine 1 (CNF-CMC-1), to give an innovative contact-active surface active against Gram-positive and Gram-negative bacteria including the methicillin-resistant S. aureus MRSA14TK301, with low potential to spread resistance and good biocompatibility, all achieved with low surface coverage. CNF-CMC-1 was particularly effective against S. aureus ATCC12528, causing virtually complete reduction of the total cells from 10(5) colony forming units (CFU)/mL bacterial suspensions, after 24 h of contact. This gentle chemical modification of the surface of CNF fully retained the beneficial properties of the original film, including moisture buffering and strength, relevant in many potential applications. Our originally designed surface represents a new class of ecofriendly biomaterials that optimizes the performance of CNF by adding antimicrobial properties without the need for environmentally toxic silver.
  • Salmikivi, Janne; Gebraad, Arjen; Seppänen-Kaijansinkko, Riitta (Helsingin yliopisto, 2017)
    The objective of this study was find out the use of dental implants, bone grafts and membrane materials used in implant dentistry between 2005-2015 in Finland. The statutory implant registry was maintained by the National Institute for Health and Welfare. Variables from the implant registry included the patient's gender, age, medical history, indications for implantation, augmentation area, installed fixtures, bone grafts and membranes, complications, removed fixtures and removal indications. Variables were analyzed by using statistical analysis software IBM® SPSS® Statistics (v24). During the time period 166 842 implants were installed and 2351 were removed. The most frequently used bone graft materials were bovine bone graft and autograft, whereas collagen membrane was the most used membrane material. Biomaterials were often used with two-step procedure and mostly in the maxilla. Patients age, gender, biomaterial use, irradiation and smoking were considered risk factors for implant survial. Information data about dental implants and biomaterial use were collected based on voluntary reports from the clinics, therefore the registry is not complete and does not represent the overall statistics.