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Loading on long bones

Rachel A Sheridan, Ann M Decker, Alexandra B Plonka, Hom-Lay Wang
PURPOSE: Occlusal overload may cause implant biomechanical failures, marginal bone loss, or even complete loss of osseointegration. Thus, it is important for clinicians to understand the role of occlusion in implant long-term stability. This systematic review updates the understanding of occlusion on dental implants, the impact on the surrounding peri-implant tissues, and the effects of occlusal overload on implants. Additionally, recommendations of occlusal scheme for implant prostheses and designs were formulated...
October 4, 2016: Implant Dentistry
Yuta Shimura, Yuji Sato, Noboru Kitagawa, Miyuki Omori
BACKGROUND: Proper implant placement is very important for long-term implant stability. Recently, numerous biomechanical studies have been conducted to clarify the relationship between implant placement and peri-implant stress. The placement of multiple implants in the edentulous posterior mandible has been studied by geometric analysis, three-dimensional finite element analysis (FEA), model experimentation, etc. Offset placement is a technique that reduces peri-implant load. However, few studies have used multiple analyses to clarify the value of the offset placement under identical conditions...
December 2016: Int J Implant Dent
Mohammad D Al Amri, Sulieman S Al-Johany, Abdulaziz M Al Baker, Mohammad Q Al Rifaiy, Tariq S Abduljabbar, Abdulaziz A Al-Kheraif
OBJECTIVE: The aim of the present 36-month prospective split-mouth clinical trial was to investigate the peri-implant soft tissue changes and crestal bone loss (CBL) around delayed loaded platform-switched implants placed at crestal and subcrestal levels. MATERIAL AND METHODS: Twenty-three individuals with bilaterally missing either mandibular first or second molars were included. The test and control sites were defined as follows: (i) test sites: implants placed 2 mm below the alveolar crest (subcrestal); (ii) control sites: implants placed at bone level (crestal)...
October 14, 2016: Clinical Oral Implants Research
A Ireland, R F Capozza, G R Cointry, L Nocciolino, J L Ferretti, J Rittweger
: Fibula response to disuse is unknown; we assessed fibula bone in spinal cord injury (SCI) patients and able-bodied counterparts. Group differences were smaller than in the neighbouring tibia which could not be explained by bone geometry. Differential adaptation of the shank bones may indicate previously unknown mechanoadaptive behaviours of bone. INTRODUCTION: The fibula supports only a small and highly variable proportion of shank compressive load (-8 to +19 %), and little is known about other kinds of stresses...
October 12, 2016: Osteoporosis International
Dongxu Liu, Zikai Hua, Xinyi Yan, Zhongmin Jin
A pelvic endoprosthesis is commonly used in orthopedic surgeries to reconstruct the pelvis after internal hemipelvectomy. This study presents the detailed design of a novel type I+II+III adjustable hemipelvic prosthesis based on the geometrical features of massive human pelvises. Finite element analysis is conducted to estimate the biomechanical performance of the newly designed adjustable hemipelvic prosthesis. Detailed numerical models of the natural and reconstructed pelvises including related soft tissues are developed...
October 6, 2016: Medical Engineering & Physics
Jinyu Li, Qin Wang, Wei Zhi, Jianxin Wang, Bo Feng, Shuxin Qu, Yandong Mu, Jie Weng
Porous hydroxyapatite (HA) scaffolds combined with a drug delivery system have attracted much attention for bone tissue engineering. In this study, an easy and highly efficient method was developed to immobilize salvianolic acid B (Sal B)-loaded chitosan (CS) microspheres three dimensionally and homogeneously on the surface of HA scaffolds pre-coated with alginate. Porous HA scaffolds were prepared via a template-leaching process and CS microspheres (used as drug carriers) were fabricated by an emulsion method...
October 7, 2016: Biomedical Materials
Tim Pearson, Mark R Glyde, Robert E Day, Giselle L Hosgood
OBJECTIVE: To investigate the effect of intramedullary pin size and plate working length on plate strain in locking compression plate-rod constructs. METHODS: A synthetic bone model with a 40 mm fracture gap was used. Locking compression plates with monocortical locking screws were tested with no pin (LCP-Mono) and intramedullary pins of 20% (LCPR-20), 30% (LCPR-30) and 40% (LCPR-40) of intramedullary diameter. Two screws per fragment modelled a long (8-hole) and short (4-hole) plate working length...
October 6, 2016: Veterinary and Comparative Orthopaedics and Traumatology: V.C.O.T
Sai Krishna Prabhala, Stanley Chien, Hiroki Yokota, Sohel Anwar
This paper presents the design of an innovative device that applies dynamic mechanical load to human knee joints. Dynamic loading is employed by applying cyclic and periodic force on a target area. The repeated force loading was considered to be an effective modality for repair and rehabilitation of long bones that are subject to ailments like fractures, osteoporosis, osteoarthritis, etc. The proposed device design builds on the knowledge gained in previous animal and mechanical studies. It employs a modified slider-crank linkage mechanism actuated by a brushless Direct Current (DC) motor and provides uniform and cyclic force...
2016: Sensors
Shabnam Samsami, Sadegh Saberi, Nima Bagheri, Gholamreza Rouhi
BACKGROUND: Vertical femoral neck fractures in the youth could be happened in high-energy accidents, and because of dominant shearing forces, this fracture is considered as a troublesome injury with a controversy regarding selection of the best fixation method. OBJECTIVE: The long term goal of this quasi-experimental study was to find the more stable fixation method among cannulated screws (CSs), proximal femoral locking plate (PFLP), and dynamic hip screw with derotational screw (DHS+DS) for this kind of fracture...
September 28, 2016: Bio-medical Materials and Engineering
Kang Chen, Ping Li, Huakun Zhao, Xiaoyan Yan, Yanhong Ma
Mechanical stress plays an important role in preserving the integrity of bone and ligament. Stress shielding reduces mechanical load on bone or tendons, resulting in tissue degradation. Previous studies showed that deterioration of the tendon structure during stress shielding is associated with elevated expression of tumor necrosis factor (TNF)-α. This study examined the therapeutic potential of the TNF inhibitor etanercept in preventing morphologic deterioration of the Achilles tendon after stress shielding...
September 29, 2016: Orthopedics
Jonas Esche, Simone Johner, Lijie Shi, Eckhard Schönau, Thomas Remer
CONTEXT: Diet can impact on bone strength via metabolic shifts in acid-base status. In contrast to the strongly diet-dependent biomarker urinary potential renal acid load (uPRAL), the amount of renally excreted citrate integrates nutritional and systemic influences on acid-base homeostasis with high citrate indicating preferential alkalization. OBJECTIVE: To examine the association between urinary citrate excretion and bone strength as well as long-term fracture risk...
September 27, 2016: Journal of Clinical Endocrinology and Metabolism
Abdelwahed Barkaoui, Rabeb Ben Kahla, Tarek Merzouki, Ridha Hambli
Bone remodeling is a physiological process by which bone constantly adapts its structure to changes in long-term loading manifested by interactions between osteoclasts and osteoblasts. This process can be influenced by many local factors, via effects on bone cells differentiation and proliferation, which are produced by bone cells and act in a paracrine or autocrine way. The aim of the current work is to provide mechanobiological finite elements modeling coupling both cellular activities and mechanical behavior in order to investigate age and gender effects on bone remodeling evolution...
September 22, 2016: Biomechanics and Modeling in Mechanobiology
Shu He, Kai-Feng Lin, Jun-Jun Fan, Gang Hu, Xin Dong, Yi-Nan Zhao, Yue Song, Zhong-Shang Guo, Long Bi, Jian Liu
A microsphere composite made of poly(DL-lactic-co-glycolic acid) (PLGA), mesoporous silica nanoparticle (MSN), and nanohydroxyapatite (nHA) (PLGA-MSN/nHA) was prepared and evaluated as bone tissue engineering materials. The objective of this study was to investigate the synergistic effect of MSN/nHA on biocompatibility as well as its potential ability for bone formation. First, we found that this PLGA-MSN/nHA composite performed good characteristics on microstructure, mechanical strength, and wettability. By cell culture experiments, the adhesion and proliferation rate of the cells seeded on PLGA-MSN/nHA composite was higher than those of the controls and high levels of osteogenetic factors such as ALP and Runx-2 were detected by reverse transcriptase polymerase chain reaction...
2016: BioMed Research International
Christoph Schnurr, Bernd Schellen, Jens Dargel, Johannes Beckmann, Peer Eysel, Reinhard Steffen
BACKGROUND: In total hip arthroplasty, short stems were developed as a bone-conserving alternative to traditional cementless stems. So far, there have been very few recorded medium to long-term results of these comparatively new implants. The aim of our retrospective study was to report on the survival of calcar-loading short stems. METHODS: All Metha stem implantations from 2004 to 2014 were recorded from the operation protocols (n = 1888). Due to the chronological development of the stem, 3 different versions were implanted: modular titanium stems with neck adapters from titanium or cobalt-chrome and monoblock stems...
August 20, 2016: Journal of Arthroplasty
Silvia Pabisch, Chika Akabane, Wolfgang Wagermaier, Andreas Roschger, Taku Ogura, Ryo Hyodo, Shinsuke Kataoka, Norio Tobori, Tomomichi Okano, Shinya Murakami, Peter Fratzl, Richard Weinkamer
Alveolar bone - the bony ridge containing the tooth sockets - stands out by its remodeling activity where bone is being formed and resorbed at a much higher rate that in any other bony tissue. Teeth that are anchored in the jaw through the periodontal ligament exert very large localized loads during mastication that could lead to a unique adaptation of the collagen/mineral structure in the bone. Our aim was to characterize the nanostructure of alveolar bone and to determine the influence of diabetes on structural characteristics of the mineralized matrix...
September 13, 2016: Journal of Structural Biology
Joseph A Toljanic, Karl Ekstrand, Russell A Baer, Andreas Thor
PURPOSE: Successful immediate loading of implants in the edentulous maxilla has been previously reported. The purpose of this 5-year prospective study was to further assess long-term outcomes following immediate loading of implants in the edentulous maxilla with fixed provisional restorations without the use of bone augmentation procedures. MATERIALS AND METHODS: Subjects with edentulous maxillary arches each received six implants placed in native bone without augmentation...
September 2016: International Journal of Oral & Maxillofacial Implants
Jun-Yu Shi, Ying-Xin Gu, Long-Fei Zhuang, Hong-Chang Lai
PURPOSE: The aim of this review was to systematically appraise survival rates of implants placed using the osteotome technique with and without grafting in the published literature. MATERIALS AND METHODS: An electronic search was conducted to identify prospective and retrospective studies on osteotome sinus floor elevation published between January 1, 2000 and October 30, 2015. Studies were included that (1) involved use of the osteotome technique with or without grafting; (2) provided data regarding the implant survival rates, residual bone height (RBH), and grafting materials; and (3) reported mean follow-up of at least 1 year after functional loading and included a minimum of 10 patients...
September 2016: International Journal of Oral & Maxillofacial Implants
S Pieralli, R J Kohal, R E Jung, K Vach, B C Spies
To determine the survival rate and marginal bone loss (MBL) of zirconia dental implants restored with single crowns or fixed dental prostheses. An electronic search was conducted up to November 2015 (without any restriction regarding the publication time) through the databases MEDLINE (PubMed), Cochrane Library, and EMBASE to identify randomized controlled clinical trials and prospective clinical trials including >15 patients. Primary outcomes were survival rate and MBL. Furthermore, the influence of several covariates on MBL was evaluated...
September 13, 2016: Journal of Dental Research
Michaël R Laurent, Ferran Jardí, Vanessa Dubois, Dieter Schollaert, Rougin Khalil, Evelien Gielen, Geert Carmeliet, Frank Claessens, Dirk Vanderschueren
Aging hypogonadal men are at increased risk of osteoporosis and sarcopenia. Testosterone is a potentially appealing strategy to prevent simultaneous bone and muscle loss. The androgen receptor (AR) mediates antiresorptive effects on trabecular bone via osteoblast-lineage cells, as well as muscle-anabolic actions. Sex steroids also modify the skeletal response to mechanical loading. However, it is unclear whether the effects of androgens on bone remain effective independent of mechanical stimulation or rather require indirect androgen effects via muscle...
September 10, 2016: Bone
Rajeev Chaudhary, Ming-Song Lee, Kuwabo Mubyana, Sarah Duenwald-Kuehl, Lyndsey Johnson, Jarred Kaiser, Ray Vanderby, Kevin W Eliceiri, David T Corr, Matthew S Chin, Wan-Ju Li, Paul J Campagnola, Matthew A Halanski
PURPOSE: The accepted mechanism explaining the accelerated growth following periosteal resection is that the periosteum serves as a mechanical restraint to restrict physeal growth. To test the veracity of this mechanism we first utilized Second Harmonic Generation (SHG) imaging to measure differences of periosteal fiber alignment at various strains. Additionally, we measured changes in periosteal growth factor transcription. Next we utilized SHG imaging to assess the alignment of the periosteal fibers on the bone both before and after periosteal resection...
November 2016: Bone
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