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Pekka K Vallittu - One of the best experts on this subject based on the ideXlab platform.

  • craniofacial bone reconstruction with bioactive fiber reinforced Composite implant
    Head and Neck-journal for The Sciences and Specialties of The Head and Neck, 2014
    Co-Authors: Kalle Aitasalo, Jaakko M Piitulainen, Jami Rekola, Pekka K Vallittu
    Abstract:

    Background A novel, bioactive, Fiber-Reinforced Composite implant is a solution to address the shortcomings in craniofacial bone reconstruction. A longitudinal clinical investigation with a follow-up time of 4 years was conducted. Methods A cranial bone reconstruction with the implant was performed on 12 patients. In these patients, the reasons for craniotomies resulting in craniofacial bone defects were traumatic and spontaneous intracranial bleeding as well as infections to the primary reconstruction material. The implant material consisted of a supporting Fiber-Reinforced framework, porous inner layers, and a bioactive glass (BG; S53P4) filling. The framework and the porous layers were made of a bisphenol-a-glycidyl methacrylate and triethyleneglycoldi-methacrylate (pBisGMA-pTEGDMA) resin matrix, which was reinforced with silanized E-glass. Results In clinical examinations and skull X-rays, the implants were in original positions providing the expected functional and aesthetic outcome at all time points. Conclusion The implants functioned appropriately, which would provide a potential solution for craniofacial bone reconstruction in the future. © 2013 Wiley Periodicals, Inc. Head Neck 36: 722–728, 2014

  • laser doppler imaging of skin microcirculation under fiber reinforced Composite framework of facial prosthesis
    Acta Odontologica Scandinavica, 2014
    Co-Authors: Rosita Kantola, Marjut Siven, Hemmo Kurunmaki, Mimmi Tolvanen, Pekka K Vallittu, Pentti Kemppainen
    Abstract:

    Abstract Objective. Glass-fiber reinforced Composite has been suggested to be used as framework material in silicone elastomer facial prostheses. The glass-fiber reinforced framework makes it possible to make the margin of the prosthesis very tight, so that it will lean tightly against the skin even during facial expressions and jaw movements. The purpose of this study was to study how the compression of the glass-fiber reinforced framework would affect the microcirculation of the facial skin. Materials and methods. A face mask, with a compression pad corresponding to the outer margin of a glass Fiber-Reinforced Composite framework beam of a facial prosthesis, was used to apply pressure on the facial skin of healthy volunteers. The skin blood flow during touch, light and moderate compression of the skin was measured by laser Doppler imaging technique. Results. None of the compressions had any marked effects on local skin blood flow. No significant differences between the blood flow of the compressed skin,...

  • single visit replacement of maxillary canine using fiber reinforced Composite resin
    The journal of contemporary dental practice, 2012
    Co-Authors: Sufyan Garoushi, Lippo V J Lassila, Pekka K Vallittu
    Abstract:

    Missing a canine is of serious concern in social life of a patient in most of societies. While conventional fixed partial dentures and implant-supported restorations may often be the treatment of choice, Fiber-Reinforced Composite (FRC) resins offer a conservative, fast and cost-effective alternative for single and multiple teeth replacement. This clinical report presents two cases where FRC technology was successfully used to restore canine edentulous area in terms of esthetic-cosmetic values and functionality.

  • load bearing capacity of human incisor restored with various fiber reinforced Composite posts
    Dental Materials, 2011
    Co-Authors: Annamaria Le Bellronnlof, Lippo V J Lassila, Ilkka Kangasniemi, Pekka K Vallittu
    Abstract:

    Abstract Objectives The aim of this study was to evaluate the load-bearing capacity and microstrain of incisors restored with posts of various kinds. Both prefabricated titanium posts and different Fiber-Reinforced Composite posts were tested. Methods The crowns of human incisors were cut and post preparation was carried out. The roots were divided into groups: (1) prefabricated serrated titanium posts, (2) prefabricated carbon Fiber-Reinforced Composite posts, (3) individually formed glass Fiber-Reinforced Composite posts with the canal full of fibers, and (4) individually formed “split” glass Fiber-Reinforced Composite posts. The posts were cemented and Composite crowns were made. Intact human incisors were used as reference. All roots were embedded in acrylic resin cylinders and stored at room temperature in water. Static load was applied under a loading angle of 45° using a universal testing machine. On half of the specimens microstrain was measured with strain gages and an acoustic emission analysis was carried out. Failure mode assessment was also made. Results The group with titanium posts showed highest number of unfavorable failures compared to the groups with Fiber-Reinforced Composite posts. Significance With Fiber-Reinforced Composite posts the failures may more often be favorable compared to titanium posts, which clinically means repairable failures.

  • three dimensional finite element analysis of posterior fiber reinforced Composite fixed partial denture framework design for pontic
    The European journal of prosthodontics and restorative dentistry, 2009
    Co-Authors: Akikazu Shinya, L V Lassila, Pekka K Vallittu
    Abstract:

    : This study investigated the effects of two types of loading conditions on mechanical behavior of the pontic of Composite fixed partial denture (C-FPD) and fiber reinforced Composite fixed partial denture (FRC-FPD). Two types of FE model of posterior bridge were developed. Two types of loading conditions, i.e. vertical 629 N, and lateral of 250 N, were used. In lateral load, displacement was showed a similar behaviours. However in vertical load, displacement of FRC-FPD was less than C-FPD. These results clarified the magnitude, distribution of stress and displacement generated in C-FPD and FRC-FPD of pontic caused by two different loading conditions.

M C Ray - One of the best experts on this subject based on the ideXlab platform.

  • smart damping of fuzzy fiber reinforced Composite plates using 1 3 piezoelectric Composites
    Journal of Vibration and Control, 2016
    Co-Authors: S I Kundalwal, M C Ray
    Abstract:

    This article is concerned with the investigation of active constrained layer damping (ACLD) of smart laminated fuzzy fiber reinforced Composite (FFRC) plates. The distinctive feature of the constru...

  • effect of carbon nanotube waviness on the effective thermoelastic properties of a novel continuous fuzzy fiber reinforced Composite
    Composites Part B-engineering, 2014
    Co-Authors: S I Kundalwal, M C Ray
    Abstract:

    Abstract This paper deals with the investigation of the effect of carbon nanotube (CNT) waviness on the effective coefficient of thermal expansion (CTE) of a novel continuous fuzzy fiber reinforced Composite (FFRC). This novel FFRC is composed of carbon fibers, sinusoidally wavy CNTs and epoxy matrix. The sinusoidally wavy CNTs are radially grown on the circumferential surfaces of the carbon fibers. Analytical micromechanics model based on the method of cells (MOC) approach is derived to investigate the influence of the waviness of CNTs on the effective CTEs of the FFRC. The present study reveals that if the amplitudes of the radially grown sinusoidally wavy CNTs are parallel to the axis of the carbon fiber then the thermoelastic properties of the FFRC are significantly improved over those of the FFRC being composed of straight CNTs.

  • geometrically nonlinear analysis of antisymmetric angle ply smart Composite plates integrated with a layer of piezoelectric fiber reinforced Composite
    Smart Materials and Structures, 2007
    Co-Authors: J Shivakumar, M C Ray
    Abstract:

    This paper is concerned with static analysis of simply supported antisymmetric angle-ply plates integrated with a layer of piezoelectric fiber reinforced Composite (PFRC) material undergoing nonlinear deformations. The Von K?rm?n type nonlinear strain displacement relations and first-order shear deformation theory are used to formulate the variational model of this electromechanical coupled problem. Subsequently, the Galerkin method is employed to derive the nonlinear algebraic governing equations which are solved by employing the Newton?Raphson method. The results suggest the potential use of PFRC material for distributed control of nonlinear deformations of smart antisymmetric angle-ply Composite plates. Particular emphasis has been placed on investigating the effect of variation of piezoelectric fiber orientation on the actuating capability of the PFRC layer for counteracting the nonlinear deformations of the smart antisymmetric angle-ply Composite plates.

S I Kundalwal - One of the best experts on this subject based on the ideXlab platform.

Lippo V J Lassila - One of the best experts on this subject based on the ideXlab platform.

  • single visit replacement of maxillary canine using fiber reinforced Composite resin
    The journal of contemporary dental practice, 2012
    Co-Authors: Sufyan Garoushi, Lippo V J Lassila, Pekka K Vallittu
    Abstract:

    Missing a canine is of serious concern in social life of a patient in most of societies. While conventional fixed partial dentures and implant-supported restorations may often be the treatment of choice, Fiber-Reinforced Composite (FRC) resins offer a conservative, fast and cost-effective alternative for single and multiple teeth replacement. This clinical report presents two cases where FRC technology was successfully used to restore canine edentulous area in terms of esthetic-cosmetic values and functionality.

  • load bearing capacity of human incisor restored with various fiber reinforced Composite posts
    Dental Materials, 2011
    Co-Authors: Annamaria Le Bellronnlof, Lippo V J Lassila, Ilkka Kangasniemi, Pekka K Vallittu
    Abstract:

    Abstract Objectives The aim of this study was to evaluate the load-bearing capacity and microstrain of incisors restored with posts of various kinds. Both prefabricated titanium posts and different Fiber-Reinforced Composite posts were tested. Methods The crowns of human incisors were cut and post preparation was carried out. The roots were divided into groups: (1) prefabricated serrated titanium posts, (2) prefabricated carbon Fiber-Reinforced Composite posts, (3) individually formed glass Fiber-Reinforced Composite posts with the canal full of fibers, and (4) individually formed “split” glass Fiber-Reinforced Composite posts. The posts were cemented and Composite crowns were made. Intact human incisors were used as reference. All roots were embedded in acrylic resin cylinders and stored at room temperature in water. Static load was applied under a loading angle of 45° using a universal testing machine. On half of the specimens microstrain was measured with strain gages and an acoustic emission analysis was carried out. Failure mode assessment was also made. Results The group with titanium posts showed highest number of unfavorable failures compared to the groups with Fiber-Reinforced Composite posts. Significance With Fiber-Reinforced Composite posts the failures may more often be favorable compared to titanium posts, which clinically means repairable failures.

  • reconstruction of critical size calvarial bone defects in rabbits with glass fiber reinforced Composite with bioactive glass granule coating
    Journal of Biomedical Materials Research Part B, 2008
    Co-Authors: Sari Tuusa, Lippo V J Lassila, Matti Peltola, Teemu Tirri, Mervi Puska, M Roytta, Heikki Aho, Jouko Sandholm, Pekka K Vallittu
    Abstract:

    The aim of this study was to evaluate glass–Fiber-Reinforced Composite as a bone reconstruction material in the critical size defects in rabbit calvarial bones. The bone defect healing process and inflammatory reactions were evaluated histologically at 4 and 12 weeks postoperatively. Possible neuropathological effects on brain tissue were evaluated. The release of residual monomers from the Fiber-Reinforced Composite (FRC) was analyzed by high performance liquid chromatograph (HPLC). Results: At 4 weeks postoperatively, fibrous connective tissue ingrowth to implant structures was seen. Healing had started as new bone formation from defect margins, as well as woven bone islets in the middle of the defect. Woven bone was also seen inside the implant. Inflammation reaction was slight. At 12 weeks, part of the new bone had matured to lamellar-type, and inflammation reaction was slight to moderate. Control defects had healed by fibrous connective tissue. Histological examinations of the brain revealed no obvious damage to brain morphology. In HPLC analysis, the release of residual 1,4-butanedioldimethacrylate and methylmethacrylate from polymerized FRC was low. Conclusions: This FRC-implant was shown to promote the healing process of critical size calvarial bone defect in rabbits. After some modifications to the material properties, this type of implant has the potential to become an alternative for the reconstruction of bone defects in the head and neck area in the future. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008

  • bond strength of Composite resin luting cements to fiber reinforced Composite root canal posts
    The journal of contemporary dental practice, 2007
    Co-Authors: Annamaria Le Bellronnlof, Milla Lahdenpera, Lippo V J Lassila, Pekka K Vallittu
    Abstract:

    Aims The aim of this study was to compare the attachment of different Composite resin luting cements to a Fiber-Reinforced Composite (FRC) post with a semi-interpenetrating polymer network polymer matrix. Methods and materials Six different brands of Composite resin luting cement stubs were applied on the surface of FRC post material and light-cured for 40 seconds. Shear bond strengths of luting cement stubs were measured using a universal testing machine. Results The differences in shear bond strengths between the cements were not statistically significant. Conclusion All of the tested Composite resin luting cements provided acceptable attachment to the tested FRC post. The tested FRC post material is suitable to use with different Composite resin luting cements.

  • fracture resistance of short randomly oriented glass fiber reinforced Composite premolar crowns
    Acta Biomaterialia, 2007
    Co-Authors: Sufyan Garoushi, Pekka K Vallittu, Lippo V J Lassila
    Abstract:

    Abstract The aim of this work was to determine the static load-bearing capacity of posterior Composite crowns made of experimental Composite resin (FC) with short fiber fillers and a semi-interpenetrating polymer network (IPN) matrix. In addition, we wanted to investigate how load-bearing capacity of surface Composite resins was affected by substructures of Fiber-Reinforced Composite (FRC) and FC, and by different curing systems. Five groups of crowns were fabricated ( n  = 6). The crowns were either polymerized with a hand-light curing unit (LCU) or cured in a vacuum curing device (VLC) before they were statically loaded at a speed of 1 mm min −1 until fracture. Failure modes were visually examined. Data were analyzed using ANOVA. ANOVA revealed that crowns made from the FC had a statistically significant higher load-bearing capacity than the control PFC Composite. Crowns with FRC substructure and PFC covering gave force values of 348 N (LCU) and 1199 N (VLC), respectively, which were lower than the values of FC Composite. No statistically significant difference was found between crowns made from plain FC Composite and those made from FC Composite with a surface layer of PFC ( P  = 0.892 and 1.00). Restorations made from short glass fiber-containing Composite resin with IPN–polymer matrix showed better load bearing capacity than those made with either plain PFC or PFC reinforced with FRC substructure.

Ariel Leonardo Stocchi - One of the best experts on this subject based on the ideXlab platform.

  • failure mode maps of natural and synthetic fiber reinforced Composite sandwich panels
    Composites Part A-applied Science and Manufacturing, 2017
    Co-Authors: Juan Pablo Vitale, Gaston Martin Francucci, Jian Xiong, Ariel Leonardo Stocchi
    Abstract:

    Abstract In the present work, mechanical properties and failure modes of natural and synthetic fiber reinforced Composite sandwich panels under three point bending were studied. Analytical models were developed in order to predict the mechanical response of all the specimens with different facesheet – core combinations. The modes studied include core shear, core crushing, face wrinkling, face yielding, and facesheet debonding. Natural fiber reinforced honeycomb and commercial PVC foam were used as cores. Jute reinforced polyester and glass fiber reinforced polyester were used as skins. Fiber reinforced honeycomb cores were obtained by Vacuum Assisted Resin Transfer Molding (VARTM). Failure mechanism maps were constructed in order to predict the failure of Composite sandwich panels. The response of the sandwich panels under three point bending was measured up to failure, and the results were compared with the analytical predictions. A good agreement between the predicted and observed modes was found.

  • Failure mode maps of natural and synthetic fiber reinforced Composite sandwich panels Part A Applied science and manufacturing
    Composites, 2017
    Co-Authors: Juan Pablo Vitale, Gaston Martin Francucci, Jian Xiong, Ariel Leonardo Stocchi
    Abstract:

    In the present work, mechanical properties and failure modes of natural and synthetic fiber reinforced Composite sandwich panels under three point bending were studied. Analytical models were developed in order to predict the mechanical response of all the specimens with different facesheet – core combinations. The modes studied include core shear, core crushing, face wrinkling, face yielding, and facesheet debonding.Natural fiber reinforced honeycomb and commercial PVC foam were used as cores. Jute reinforced polyester and glass fiber reinforced polyester were used as skins. Fiber reinforced honeycomb cores were obtained by Vacuum Assisted Resin Transfer Molding (VARTM).Failure mechanism maps were constructed in order to predict the failure of Composite sandwich panels. The response of the sandwich panels under three point bending was measured up to failure, and the results were compared with the analytical predictions. A good agreement between the predicted and observed modes was found.