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Kriging Surrogate Model for Resonance Frequency Analysis of Dental Implants by a Latin Hypercube-Based Finite Element Method. Appl Bionics Biomech 2019; 2019:3768695. [PMID: 31093299 PMCID: PMC6481145 DOI: 10.1155/2019/3768695] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 02/03/2019] [Accepted: 03/13/2019] [Indexed: 11/18/2022] Open
Abstract
The dental implantation in clinical operations often encounters difficulties and challenges of failure in osseointegration, bone formulation, and remodeling. The resonance frequency (RF) can effectively describe the stability of the implant in physical experiments or numerical simulations. However, the exact relationship between the design variables of dental implants and RF of the system is correlated, complicated, and dependent. In this study, an appropriate mathematical model is proposed to evaluate and predict the implant stability and performance. The model has merits not only in the prediction reliability and accuracy but also in the compatibility and flexibility, in both experimental data and numerical simulation results. The Kriging surrogate model is proposed to present the numerical relationship between RF and material parameters of dental implants. The Latin Hypercube (LH) sampling method as a competent and sophisticated method is applied and combined with the finite element method (FEM). The methods developed in this paper provide helpful guidance for designers and researchers in the implantation design and surgical plans.
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Wang L, Hsu HY, Li X, Xian CJ. Effects of Frequency and Acceleration Amplitude on Osteoblast Mechanical Vibration Responses: A Finite Element Study. BIOMED RESEARCH INTERNATIONAL 2016; 2016:2735091. [PMID: 28074178 PMCID: PMC5198261 DOI: 10.1155/2016/2735091] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 09/29/2016] [Accepted: 10/20/2016] [Indexed: 11/17/2022]
Abstract
Bone cells are deformed according to mechanical stimulation they receive and their mechanical characteristics. However, how osteoblasts are affected by mechanical vibration frequency and acceleration amplitude remains unclear. By developing 3D osteoblast finite element (FE) models, this study investigated the effect of cell shapes on vibration characteristics and effect of acceleration (vibration intensity) on vibrational responses of cultured osteoblasts. Firstly, the developed FE models predicted natural frequencies of osteoblasts within 6.85-48.69 Hz. Then, three different levels of acceleration of base excitation were selected (0.5, 1, and 2 g) to simulate vibrational responses, and acceleration of base excitation was found to have no influence on natural frequencies of osteoblasts. However, vibration response values of displacement, stress, and strain increased with the increase of acceleration. Finally, stress and stress distributions of osteoblast models under 0.5 g acceleration in Z-direction were investigated further. It was revealed that resonance frequencies can be a monotonic function of cell height or bottom area when cell volumes and material properties were assumed as constants. These findings will be useful in understanding how forces are transferred and influence osteoblast mechanical responses during vibrations and in providing guidance for cell culture and external vibration loading in experimental and clinical osteogenesis studies.
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Affiliation(s)
- Liping Wang
- The Third Affiliated Hospital of Southern Medical University, Orthopaedic Hospital of Guangdong Province, Guangzhou 510630, China
- Sansom Institute for Health Research, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, SA 5001, Australia
| | - Hung-Yao Hsu
- School of Engineering, University of South Australia, Adelaide, SA 5095, Australia
| | - Xu Li
- The Third Affiliated Hospital of Southern Medical University, Orthopaedic Hospital of Guangdong Province, Guangzhou 510630, China
| | - Cory J. Xian
- The Third Affiliated Hospital of Southern Medical University, Orthopaedic Hospital of Guangdong Province, Guangzhou 510630, China
- Sansom Institute for Health Research, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, SA 5001, Australia
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Dai J, Cheng N, Miron RJ, Shi B, Cheng X, Zhang Y. Effect of decreased implant healing time on bone (re)modeling adjacent to plateaued implants under functional loading in a dog model. Clin Oral Investig 2013; 18:77-86. [PMID: 23377840 DOI: 10.1007/s00784-013-0929-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Accepted: 01/23/2013] [Indexed: 12/26/2022]
Abstract
OBJECTIVES The purpose of this study was to evaluate the effect of early functional loading to plateaued implants on bone formation and implant stability in a dog model. MATERIALS AND METHODS Early loading (EL), nonloading control, and delayed loading (DL) groups were compared using six beagle dogs under functional loading. The Periotest® values were measured dynamically for 6 weeks. Peri-implant bone architecture was evaluated qualitatively by microcomputed tomography (μCT) and analyzed quantitatively by mineral apposition rates (MAR), bone-to-implant contact (BIC), and bone volumes (BV/TV) after the euthanasia at 3 and 6 weeks after loading. RESULTS The EL implants showed poor stability at 1 week, but greater stability at 2 and 4 weeks after loading compared to DL implants. There was no significant difference between MAR of EL and unloaded implants at both time intervals. The EL implants displayed a significantly higher MAR when compared to DL implants at 3-5 weeks. A significantly higher BIC for the DL group was observed when compared to the EL group at 3 weeks following loading, however at 6 weeks; no significant difference between these groups was observed. The EL group gained a higher BIC than the no-treatment control group at 6 weeks. CONCLUSIONS For plateaued implant, the decreased healing time (1 week) displays a positive effect on peri-implant bone (re)modeling under functional loading during the early phase. CLINICAL RELEVANCE The early application of functional loading on plateaued implants can be used clinically to shorten the course of treatment and improve esthetics.
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Affiliation(s)
- Jing Dai
- Ministry Education Key Laboratory for Oral Biomedical Engineering, School & Hospital of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan, 430079, People's Republic of China
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Zhang X, Torcasio A, Vandamme K, Ogawa T, van Lenthe GH, Naert I, Duyck J. Enhancement of implant osseointegration by high-frequency low-magnitude loading. PLoS One 2012; 7:e40488. [PMID: 22808172 PMCID: PMC3393711 DOI: 10.1371/journal.pone.0040488] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2012] [Accepted: 06/08/2012] [Indexed: 01/10/2023] Open
Abstract
Background Mechanical loading is known to play an important role in bone remodelling. This study aimed to evaluate the effect of high- and low-frequency axial loading, applied directly to the implant, on peri-implant bone healing and implant osseointegration. Methodology Titanium implants were bilaterally installed in rat tibiae. For every animal, one implant was loaded (test) while the other one was not (control). The test implants were randomly divided into 8 groups according to 4 loading regimes and 2 experimental periods (1 and 4 weeks). The loaded implants were subject to an axial displacement. Within the high- (HF, 40 Hz) or low-frequency (LF, 8 Hz) loading category, the displacements varied 2-fold and were ranked as low- or high-magnitude (LM, HM), respectively. The strain rate amplitudes were kept constant between the two frequency groups. This resulted in the following 4 loading regimes: 1) HF-LM, 40 Hz-8 µm; 2) HF-HM, 40 Hz-16 µm; 3) LF-LM, 8 Hz-41 µm; 4) LF-HM, 8 Hz-82 µm. The tissue samples were processed for resin embedding and subjected to histological and histomorphometrical analyses. Data were analyzed statistically with the significance set at p<0.05. Principal Findings After loading for 4 weeks, HF-LM loading (40 Hz-8 µm) induced more bone-to-implant contact (BIC) at the level of the cortex compared to its unloaded control. No significant effect of the four loading regimes on the peri-implant bone fraction (BF) was found in the 2 experimental periods. Conclusions The stimulatory effect of immediate implant loading on bone-to-implant contact was only observed in case of high-frequency (40 Hz) low-magnitude (8 µm) loading. The applied load regimes failed to influence the peri-implant bone mass.
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Affiliation(s)
- Xiaolei Zhang
- Department of Prosthetic Dentistry, BIOMAT Research Cluster, University of Leuven, Leuven, Belgium
| | - Antonia Torcasio
- Department of Mechanical Engineering, Division of Biomechanics and Engineering Design, University of Leuven, Leuven, Belgium
| | - Katleen Vandamme
- Department of Prosthetic Dentistry, BIOMAT Research Cluster, University of Leuven, Leuven, Belgium
| | - Toru Ogawa
- Department of Prosthetic Dentistry, BIOMAT Research Cluster, University of Leuven, Leuven, Belgium
- Division of Advanced Prosthetic Dentistry, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - G. Harry van Lenthe
- Department of Mechanical Engineering, Division of Biomechanics and Engineering Design, University of Leuven, Leuven, Belgium
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
| | - Ignace Naert
- Department of Prosthetic Dentistry, BIOMAT Research Cluster, University of Leuven, Leuven, Belgium
| | - Joke Duyck
- Department of Prosthetic Dentistry, BIOMAT Research Cluster, University of Leuven, Leuven, Belgium
- * E-mail:
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Mariani S, Fiore D, Barbaro G, Basciani S, Saponara M, D'Arcangelo E, Ulisse S, Moretti C, Fabbri A, Gnessi L. Association of epicardial fat thickness with the severity of obstructive sleep apnea in obese patients. Int J Cardiol 2012; 167:2244-9. [PMID: 22726396 DOI: 10.1016/j.ijcard.2012.06.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 06/06/2012] [Accepted: 06/07/2012] [Indexed: 12/27/2022]
Abstract
BACKGROUND The correlation between obesity and severity of obstructive sleep apnea (OSA) is controversial. Although fat excess is a predisposing factor for the development of OSA, it has not been determined whether fat distribution rather than obesity per se is associated with OSA severity. Epicardial fat thickness (EFT) is an independent index of visceral adiposity and cardiometabolic risk. We investigated the relation between fat distribution and cardiometabolic risk factors, including EFT and common carotid intima-media thickness (cIMT), with the severity of OSA in obese patients. METHODS One hundred and fifteen obese patients (56 males, 59 females) with polysomnographic evidence of OSA (≥ 5 apnea/hypopnea events per hour) of various degrees, without significant differences in grade of obesity as defined by body mass index (BMI), were evaluated. The following parameters were measured: BMI, body composition by dual energy X-ray absorptiometry, EFT, right ventricular end-diastolic diameter (RVEDD) and cIMT by ultrasound, and parameters of metabolic syndrome (waist circumference, arterial blood pressure, fasting glucose, HDL-cholesterol and triglycerides). RESULTS EFT, RVEDD, cIMT and trunk/leg fat mass ratio showed a positive correlation with OSA severity in univariate analysis (r=0.536, p<0.001; r=0.480, p<0.001; r=0.345, p<0.001; r=0.330, p<0.001, respectively). However, multiple linear regression analysis showed that EFT was the most significant independent correlate of the severity of OSA (R(2)=0.376, p=0.022). CONCLUSIONS The present study suggests that, in obese patients, EFT may be included among the clinical parameters associating with OSA severity. The association of EFT with OSA, both cardiovascular risk factors, is independent of obesity as defined by classical measures.
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Affiliation(s)
- Stefania Mariani
- Department of Experimental Medicine, Section of Medical Physiopathology and Endocrinology, Sapienza University of Rome, Rome, Italy
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Zhang X, Vandamme K, Torcasio A, Ogawa T, van Lenthe GH, Naert I, Duyck J. In vivo assessment of the effect of controlled high- and low-frequency mechanical loading on peri-implant bone healing. J R Soc Interface 2012; 9:1697-704. [PMID: 22279157 DOI: 10.1098/rsif.2011.0820] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The aim of this study was to investigate the effect of controlled high- (HF) and low-frequency (LF) mechanical loading on peri-implant bone healing. Custom-made titanium implants were inserted in both tibiae of 69 adult Wistar rats. For every animal, one implant was loaded by compression through the axis of tibia (test), whereas the other one was unloaded (control). The test implants were randomly distributed among four groups receiving different loading regimes, which were determined by ex vivo calibration. Within the HF (40 Hz) or LF (2 Hz) loading category, the magnitudes were chosen as low- (LM) and high-magnitude (HM), respectively, leading to constant strain rate amplitudes for the two frequency groups. This resulted in the four loading regimes: (i) HF-LM (40 Hz-0.5 N); (ii) HF-HM (40 Hz-1 N); (iii) LF-LM (2 Hz-10 N); and (iv) LF-HM (2 Hz-20 N) loading. Loading was performed five times per week and lasted for one or four weeks. Tissue samples were processed for histology and histomorphometry (bone-to-implant contact, BIC; and peri-implant bone fraction, BF) at the cortical and medullar level. Data were analysed statistically with ANOVA and paired t-tests with the significance level set at 0.05. For the one-week experiments, an increased BF adjacent to the implant surface at the cortical level was exclusively induced by the LF-HM loading regime (2 Hz-20 N). Four weeks of loading resulted in a significant effect on BIC (and not on BF) in case of HF-LM loading (40 Hz-0.5 N) and LF-HM loading (2 Hz-20 N): BIC at the cortical level significantly increased under both loading regimes, whereas BIC at the medullar level was positively influenced only in case of HF-LM loading. Mechanical loading at both HF and LF affects osseointegration and peri-implant BF. Higher loading magnitudes (and accompanying elevated tissue strains) are required under LF loading to provoke a positive peri-implant bone response, compared with HF loading. A sustained period of loading at HF is needed to result in an overall enhanced osseointegration.
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Affiliation(s)
- Xiaolei Zhang
- Department of Prosthetic Dentistry, BIOMAT Research Cluster, Biomechanics Section, KU Leuven, Leuven, Belgium
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Tirkkonen L, Halonen H, Hyttinen J, Kuokkanen H, Sievänen H, Koivisto AM, Mannerström B, Sándor GKB, Suuronen R, Miettinen S, Haimi S. The effects of vibration loading on adipose stem cell number, viability and differentiation towards bone-forming cells. J R Soc Interface 2011; 8:1736-47. [PMID: 21613288 DOI: 10.1098/rsif.2011.0211] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Mechanical stimulation is an essential factor affecting the metabolism of bone cells and their precursors. We hypothesized that vibration loading would stimulate differentiation of human adipose stem cells (hASCs) towards bone-forming cells and simultaneously inhibit differentiation towards fat tissue. We developed a vibration-loading device that produces 3g peak acceleration at frequencies of 50 and 100 Hz to cells cultured on well plates. hASCs were cultured using either basal medium (BM), osteogenic medium (OM) or adipogenic medium (AM), and subjected to vibration loading for 3 h d(-1) for 1, 7 and 14 day. Osteogenesis, i.e. differentiation of hASCs towards bone-forming cells, was analysed using markers such as alkaline phosphatase (ALP) activity, collagen production and mineralization. Both 50 and 100 Hz vibration frequencies induced significantly increased ALP activity and collagen production of hASCs compared with the static control at 14 day in OM. A similar trend was detected for mineralization, but the increase was not statistically significant. Furthermore, vibration loading inhibited adipocyte differentiation of hASCs. Vibration did not affect cell number or viability. These findings suggest that osteogenic culture conditions amplify the stimulatory effect of vibration loading on differentiation of hASCs towards bone-forming cells.
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Affiliation(s)
- Laura Tirkkonen
- Institute of Biomedical Technology, University of Tampere, Finland.
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