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David S Freedman, Joseph B Schroeder, Gregory I Telian, Zhengyang Zhang, Smrithi Sunil, Jason T Ritt
OBJECTIVE: Behavioral neuroscience studies in freely moving rodents require small, light-weight implants to facilitate neural recording and stimulation. Our goal was to develop an integrated package of 3D printed parts and assembly aids for labs to rapidly fabricate, with minimal training, an implant that combines individually positionable microelectrodes, an optical fiber, zero insertion force (ZIF-clip) headstage connection, and secondary recording electrodes, e.g. for electromyography (EMG)...
October 20, 2016: Journal of Neural Engineering
Maria Lennerås, Georgios Tsikandylakis, Margarita Trobos, Omar Omar, Forugh Vazirisani, Anders Palmquist, Örjan Berlin, Rickard Brånemark, Peter Thomsen
The breach of the skin barrier is a critical issue associated with the treatment of individuals with transfemoral amputation (TFA) using osseointegrated, percutaneous titanium implants. Thirty TFA patients scheduled for abutment exchange or removal were consecutively enrolled. The aims were to determine the macroscopic skin signs, the presence of bacteria and the gene expression in abutment-adherent cells and to conduct correlative and comparative analyses between the different parameters. Redness and a granulation ring were present in 47% of the patients...
October 17, 2016: Journal of Biomedical Materials Research. Part A
Bruno R Chrcanovic, Jenö Kisch, Tomas Albrektsson, Ann Wennerberg
OBJECTIVES: To assess the survival of dental implants placed in sites of previously failed implants and to explore the possible factors that might affect the outcome of this reimplantation procedure. MATERIALS AND METHODS: Patients that had failed dental implants, which were replaced with the same implant type at the same site, were included. Descriptive statistics were used to describe the patients and implants; survival analysis was also performed. The effect of systemic, environmental, and local factors on the survival of the reoperated implants was evaluated...
October 14, 2016: Clinical Oral Implants Research
Hong Shi, Su-Yu Chen, Yong-Guang Wang, Sheng-Jun Jiang, He-Li Cai, Kai Lin, Zhao-Fei Xie, Fen-Fang Dong
AIM: To introduce natural orifice transgastric endoscopic surgery (NOTES) tube ileostomy using pelvis-directed submucosal tunneling endoscopic gastrostomy and endoscopic tube ileostomy. METHODS: Six live pigs (three each in the non-survival and survival groups) were used. A double-channeled therapeutic endoscope was introduced perorally into the stomach. A gastrostomy was made using a 2-cm transversal mucosal incision following the creation of a 5-cm longitudinal pelvis-directed submucosal tunnel...
October 7, 2016: World Journal of Gastroenterology: WJG
Eric MacDonald, Ryan Wicker
Layer-by-layer deposition of materials to manufacture parts-better known as three-dimensional (3D) printing or additive manufacturing-has been flourishing as a fabrication process in the past several years and now can create complex geometries for use as models, assembly fixtures, and production molds. Increasing interest has focused on the use of this technology for direct manufacturing of production parts; however, it remains generally limited to single-material fabrication, which can limit the end-use functionality of the fabricated structures...
September 30, 2016: Science
Dennis Flanagan
E. faecalis appears in many tooth root infections and is not eliminated by root canal therapy. It can reside in tooth root canals and the surrounding bone. This species may vegetate in bone after extraction of an infected tooth and colonize a dental implant after placement in the healed site. A colonization may cause fixture loss or marginal bone loss. These colonizations are generally multi-bacterial and pathogenic properties can be shared via plasmids. However, E. faecalis is not detectable with some culture techniques and thus can be missed...
October 4, 2016: Journal of Oral Implantology
Christina L Hvaring, Bjørn Øgaard, Kari Birkeland
INTRODUCTION: Children with severe hypodontia have a substantial impairment of their dental health starting early in life. The purpose of this study was to describe types and locations of substitutes for missing teeth in patients with severe hypodontia and to compare the crown and soft tissue morphologies of orthodontic space closure, dental implants, and tooth-supported fixed dental prostheses for replacing teeth in the anterior region. METHODS: Fifty patients missing 6 or more teeth and aged 18 years or older (mean age, 25...
October 2016: American Journal of Orthodontics and Dentofacial Orthopedics
Gregory I Peterson, Johanna J Schwartz, Di Zhang, Benjamin M Weiss, Mark A Ganter, Duane W Storti, Andrew J Boydston
We describe an efficient method to produce objects comprising spatially controlled and graded cross-link densities using vat photopolymerization additive manufacturing (AM). Using a commercially available diacrylate-based photoresin, 3D printer, and digital light processing (DLP) projector, we projected grayscale images to print objects in which the varied light intensity was correlated to controlled cross-link densities and associated mechanical properties. Cylinder and bar test specimens were used to establish correlations between light intensities used for printing and cross-link density in the resulting specimens...
October 11, 2016: ACS Applied Materials & Interfaces
Hsiang-Hsi Hong, Adrienne Hong, Lan-Yan Yang, Wei-Yang Chang, Yi-Fang Huang, Yen-Ting Lin
BACKGROUND: Clinical conclusions in studying the stability and osseointegration of mandibular implants positioned using the bone expansion techniques are conflicting and limited. PURPOSE: The objective was to examine the implant stability quotient (ISQ) values of mandibular posterior dental implants with 4.1 mm diameter that inserted with osteotome bone expansion technique versus conventional drilling technique during a 12-week observation period. MATERIALS AND METHODS: Twenty-four implants with 4...
September 25, 2016: Clinical Implant Dentistry and related Research
Chin Tat Lim, David Q K Ng, Ken Jin Tan, Amit K Ramruttun, Wilson Wang, Desmond Y R Chong
BACKGROUND: Autologous bone graft remains the gold standard source of bone graft. Iliac crest has traditionally been the most popular source for autologous bone graft. However, iliac crest bone graft harvesting is associated with high donor site morbidity. Bone graft harvesting from the proximal tibia has shown great potential with reported low complication rates. However, there is a paucity of biomechanical studies concerning the safety as well as yield of proximal bone graft harvesting...
September 13, 2016: Injury
Andreas Kurbad
The use of materials with elastic properties for the fabrication of dental implant superstructures seems to be a promising way to reduce the functional occlusal forces on implants. Vita Enamic (Vita Zahnfabrik, Bad Säckingen), a hybrid ceramic material for CAD/CAM technology, is available in a special form that can be relatively easily combined with titanium (Ti) base connectors for the fabrication of abutment crowns and mesostructures. Thus, an easily manageable method is available for reducing peak loads on dental implant fixtures...
2016: International Journal of Computerized Dentistry
Richard C Petersen, Perng-Ru Liu
Photocure fiber-reinforced composites (FRCs) with varying chopped quartz-fiber lengths were incorporated into a dental photocure zirconia-silicate particulate-filled composite (PFC) for mechanical test comparisons with a popular commercial spherical-particle amalgam. FRC lengths included 0.5-mm, 1.0 mm, 2.0 mm, and 3.0 mm all at a constant 28.2 volume percent. Four-point fully articulated fixtures were used according to American Standards Test Methods with sample dimensions of 2×2×50 mm(3) across a 40 mm span to provide sufficient Euler flexural bending and prevent top-load compressive shear error...
2016: J Compos
Nathaniel C Lawson, Ritika Bansal, John O Burgess
OBJECTIVE: To measure the mechanical properties of several CAD/CAM materials, including lithium disilicate (e.max CAD), lithium silicate/zirconia (Celtra Duo), 3 resin composites (Cerasmart, Lava Ultimate, Paradigm MZ100), and a polymer infiltrated ceramic (Enamic). METHODS: CAD/CAM blocks were sectioned into 2.5mm×2.5mm×16mm bars for flexural strength and elastic modulus testing and 4mm thick blocks for hardness and wear testing. E.max CAD and half the Celtra Duo specimens were treated in a furnace...
September 14, 2016: Dental Materials: Official Publication of the Academy of Dental Materials
Dennis Flanagan
A fractured abutment screw of a crown supported by an endosseous implant is a complication. The fragment in the fixture can be retrieved with a festooned #557 latch burr set in reverse torque and subsequent clockwise turning #33 1/3 burr touched to the fragment side. The cemented abutment and crown can be salvaged by heating the crown/coronal screw fragment to 1000 degrees C for 20 minutes. Upon cooling, the crown and abutment can be then separated. A new abutment screw can then be used. The patient's diet, occlusal scheme and maximal bite force should be assessed...
September 6, 2016: Journal of Oral Implantology
Adam Hart, Edward J Harvey, Reza Rabiei, Francois Barthelat, Paul A Martineau
To promote a quicker return to function, an increasing number of patients are treated with headless screws for acute displaced and even non-displaced scaphoid fractures. Therefore, it is imperative to understand and optimize the biomechanical characteristics of different implants to support the demands of early mobilization. The objective of this study was to evaluate the biomechanical fixation strength of 4 headless compression screws under distracting and bending forces. The Acutrak Standard, Acutrak Mini, Synthes 3...
October 2016: Medical Engineering & Physics
Nikhil Padhye, David M Parks, Alexander H Slocum, Bernhardt L Trout
Symmetrically bonded thin and flexible T-peel specimens, when tested on vertical travel machines, can be subject to significant gravitational loading, with the associated asymmetry and mixed-mode failure during peeling. This can cause erroneously high experimental peel forces to be recorded which leads to uncertainty in estimating interfacial fracture toughness and failure mode. To overcome these issues, a mechanical test fixture has been designed, for use with vertical test machines, that supports the unpeeled portion of the test specimen and suppresses parasitic loads due to gravity from affecting the peel test...
August 2016: Review of Scientific Instruments
F J López-Valdés, O Juste-Lorente, M Maza-Frechin, B Pipkorn, C Sunnevang, A Lorente, A Aso-Vizan, J Davidsson
OBJECTIVE: The objective of this article is to analyze the kinematics and dynamics of restrained postmortem human surrogates (PMHS) exposed to a nearside oblique impact and the injuries that were found after the tests. METHODS: Three male PMHS of similar age (64 ± 4 years) and anthropometry (weight: 61 ± 9.6 kg; stature: 172 ± 2.7 cm) were exposed to a 30° nearside oblique impact at 34 km/h. The test fixture approximated the seating position of a front seat occupant...
September 2016: Traffic Injury Prevention
Renee M Banakis Hartl, Jameson K Mattingly, Nathaniel T Greene, Herman A Jenkins, Stephen P Cass, Daniel J Tollin
HYPOTHESIS: A cochlear implant electrode within the cochlea contributes to the air-bone gap (ABG) component of postoperative changes in residual hearing after electrode insertion. BACKGROUND: Preservation of residual hearing after cochlear implantation has gained importance as simultaneous electric-acoustic stimulation allows for improved speech outcomes. Postoperative loss of residual hearing has previously been attributed to sensorineural changes; however, presence of increased postoperative ABG remains unexplained and could result in part from altered cochlear mechanics...
October 2016: Otology & Neurotology
Janghyun Paek, Yi-Hyung Woo, Hyeong-Seob Kim, Ahran Pae, Kwantae Noh, Hyeonjong Lee, Kung-Rock Kwon
PURPOSE: The aim of this study was to determine the stability of computer-aided design and manufacturing (CAD/CAM) and prefabricated abutment by measuring removal torque before and after cyclic loading. MATERIALS AND METHODS: Three types of fixture and 2 types of abutments were used. Removable torque was measured after cyclic loading for 5000 cycles between 25 and 250 N for each group. The same procedure was performed twice. RESULTS: First, removal torque values (Newton centimeter) were measured for stock versus custom abutments as follows: group 1: 27...
August 26, 2016: Implant Dentistry
John Hickner
Violence and discrimination, like chronic disease, seem to be permanent fixtures on the human landscape. What can we do to prevent and mitigate these evils?
July 2016: Journal of Family Practice
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