Displaying publications 61 - 80 of 168 in total

Abstract:
Sort:
  1. Gholizadeh H, Abu Osman NA, Eshraghi A, Ali S, Arifin N, Wan Abas WA
    Biomed Eng Online, 2014;13:1.
    PMID: 24410918 DOI: 10.1186/1475-925X-13-1
    Good prosthetic suspension system secures the residual limb inside the prosthetic socket and enables easy donning and doffing. This study aimed to introduce, evaluate and compare a newly designed prosthetic suspension system (HOLO) with the current suspension systems (suction, pin/lock and magnetic systems).
    Matched MeSH terms: Prosthesis Design
  2. Baharuddin MY, Salleh ShH, Suhasril AA, Zulkifly AH, Lee MH, Omar MA, et al.
    Artif Organs, 2014 Jul;38(7):603-8.
    PMID: 24404766 DOI: 10.1111/aor.12222
    Total hip arthroplasty is a flourishing orthopedic surgery, generating billions of dollars of revenue. The cost associated with the fabrication of implants has been increasing year by year, and this phenomenon has burdened the patient with extra charges. Consequently, this study will focus on designing an accurate implant via implementing the reverse engineering of three-dimensional morphological study based on a particular population. By using finite element analysis, this study will assist to predict the outcome and could become a useful tool for preclinical testing of newly designed implants. A prototype is then fabricated using 316L stainless steel by applying investment casting techniques that reduce manufacturing cost without jeopardizing implant quality. The finite element analysis showed that the maximum von Mises stress was 66.88 MPa proximally with a safety factor of 2.39 against endosteal fracture, and micromotion was 4.73 μm, which promotes osseointegration. This method offers a fabrication process of cementless femoral stems with lower cost, subsequently helping patients, particularly those from nondeveloped countries.
    Matched MeSH terms: Prosthesis Design
  3. Mehrali M, Shirazi FS, Mehrali M, Metselaar HS, Kadri NA, Osman NA
    J Biomed Mater Res A, 2013 Oct;101(10):3046-57.
    PMID: 23754641 DOI: 10.1002/jbm.a.34588
    Functionally graded material (FGM) is a heterogeneous composite material including a number of constituents that exhibit a compositional gradient from one surface of the material to the other subsequently, resulting in a material with continuously varying properties in the thickness direction. FGMs are gaining attention for biomedical applications, especially for implants, owing to their reported superior composition. Dental implants can be functionally graded to create an optimized mechanical behavior and achieve the intended biocompatibility and osseointegration improvement. This review presents a comprehensive summary of biomaterials and manufacturing techniques researchers employ throughout the world. Generally, FGM and FGM porous biomaterials are more difficult to fabricate than uniform or homogenous biomaterials. Therefore, our discussion is intended to give the readers about successful and obstacles fabrication of FGM and porous FGM in dental implants that will bring state-of-the-art technology to the bedside and develop quality of life and present standards of care.
    Matched MeSH terms: Dental Prosthesis Design
  4. Cheah PS, Norhani M, Bariah MA, Myint M, Lye MS, Azian AL
    Cornea, 2008 May;27(4):461-70.
    PMID: 18434851 DOI: 10.1097/ICO.0b013e318165642c
    To investigate the histological changes in primate cornea induced by short-term overnight orthokeratology (OK).
    Matched MeSH terms: Prosthesis Design
  5. Bonfield W
    Med J Malaysia, 2004 May;59 Suppl B:1.
    PMID: 15468788
    Matched MeSH terms: Prosthesis Design
  6. Choudhury D, Lackner JM, Major L, Morita T, Sawae Y, Bin Mamat A, et al.
    J Mech Behav Biomed Mater, 2016 06;59:586-595.
    PMID: 27085502 DOI: 10.1016/j.jmbbm.2016.04.004
    This study investigates the durability of functional diamond-like carbon (DLC) coated titanium alloy (Ti-6Al-4V) under edge loading conditions for application in artificial hip joints. The multilayered (ML) functional DLC coatings consist of three key layers, each of these layers were designed for specific functions such as increasing fracture strength, adapting stress generation and enhancing wear resistance. A 'ball-on-disk' multi-directional wear tester was used in the durability test. Prior to the wear testing, surface hardness, modulus elasticity and Raman intensity were measured. The results revealed a significant wear reduction to the DLC coated Ti-6Al-4V disks compared to that of non-coated Ti-6Al-4V disks. Remarkably, the counterpart Silicon Nitride (Si3N4) balls also yielded lowered specific wear rate while rubbed against the coated disks. Hence, the pairing of a functional multilayered DLC and Si3N4 could be a potential candidate to orthopedics implants, which would perform a longer life-cycle against wear caused by edge loading.
    Matched MeSH terms: Prosthesis Design
  7. Soo CS, Ca M, Tay M, Yeoh JK, Sim E, Choo M
    J Am Soc Echocardiogr, 1994 3 1;7(2):159-64.
    PMID: 8185960
    We prospectively studied 37 consecutive patients implanted with the Carbomedics prosthetic heart value in the mitral position (without clinical evidence of prosthetic valve dysfunction) with two-dimensional and Doppler echocardiography. The peak mitral prosthetic gradient ranged from 4.60 to 14.63 (mean 8.97 +/- 2.29) mm Hg; mean mitral prosthetic gradient ranged from 1.67 to 6.18 (mean 3.24 +/- 0.95) mm Hg; pressure half-time derived mitral valve area ranged from 1.67 to 5.30 (mean 2.70 +/- 0.80) cm2. These values compare favorably with that of another bileaflet valve (i.e., the St. Jude Medical valve). There was a wide overlap in peak and mean transmitral gradients, even with the valves of the same size, with a significant but weak inverse relationship between peak mitral gradients and valve size (p = 0.03, r = -0.36). The performance index showed a smaller range of values, again with a significant but weak inverse relationship with valve size (p = 0.001, r = -0.54). The inverse relationship between valve size and peak mitral gradient and performance index should be borne in mind when analyzing Doppler hemodynamic data.
    Matched MeSH terms: Prosthesis Design
  8. Alkhatib SE, Tarlochan F, Mehboob H, Singh R, Kadirgama K, Harun WSBW
    Artif Organs, 2019 Jul;43(7):E152-E164.
    PMID: 30805945 DOI: 10.1111/aor.13444
    The mismatch between stiffness of the femoral dense stem and host bone causes complications to patients, such as aseptic loosening and bone resorption. Three-dimensional finite-element models of homogeneous porous (HGP) and functionally graded porous (FGP) stems incorporating body-centered cubic (BCC) structures are proposed in this article as an alternative to the dense stems. The relationship between the porosity and strut thickness of the BCC structure was developed to construct the finite-element models. Three levels of porosities (20%, 50%, and 80%) were modeled in HGP and FGP stems. The porosity of the stems was decreased distally according to the sigmoid function (n = 0.1, n = 1 and n = 10) with 3 grading exponents. The results showed that FGP stems transferred 120%-170% higher stresses to the femur (Gruen zone 7) as compared to the solid stem. Conversely, the stresses in HGP and FGP stems were 12%-34% lower than the dense stem. The highest micromotions (105-147 µm) were observed for stems of 80% overall porosity, and the lowest (42-46 µm) was for stems of 20% overall porosity. Finally, FGP stems with a grading exponent of n = 10 resulted in an 11%-28% reduction in micromotions.
    Matched MeSH terms: Prosthesis Design
  9. Rahman SA, Muhammad H, Haque S, Alam MK
    J Contemp Dent Pract, 2019 Feb 01;20(2):173-178.
    PMID: 31058631
    AIM: The aim of this study was to evaluate the changes in the peri-implant hard and soft tissues and implant stability and to assess the correlation of bone loss and peri-implant probing depth with implant stability.

    MATERIALS AND METHODS: Twenty-one patients with implants were included in this study and implants were assessed by resonance frequency analysis (RFA). Bone levels of the implants were assessed by measuring mesial and distal bone levels from the periapical radiograph, and soft tissue was assessed from probing depth using a periodontal probe. Implants were assessed for stability and probing depth at pre-loading, at 3 months and 6 months post-loading. RFA and probing depth were statistically compared from different time points. Correlation of probing depth and marginal bone loss with implant stability was also determined.

    RESULTS: The average change in implant stability quotient (ISQ) measurements from pre-loading to 6 months post-loading was found to be statistically significant (p <0.005). The average probing depth reduced from 1.767 mm at pre-loading to 1.671 mm at post-loading 3 months, and 1.600 mm at post-loading 6 months. At 6 months of function, radiographic examination yielded 0.786 mm mesial bone loss and 0.8 mm distal bone loss. It was found to be statistically significant (p <0.005) but within an acceptable range. No significant correlation was found between implant stability and bone loss; and implant stability and probing depth.

    CONCLUSION: The study revealed an increasing trend in implant stability values with the time that indicates successful osseointegration. Increasing mean values for mesial and distal bone loss were also found.

    CLINICAL SIGNIFICANCE: The success of dental implants is highly dependent on the quality of bone and implant-bone interface, i.e., osseointegration. The most important factors that influence the survival rate of an implant is initial stability. The present study found the changes in the peri-implant hard and soft tissues and implant stability. This article, while being a prospective study, may show the evidence of successful osseointegration by increasing trend in implant stability (RFA) values with time which can help to the clinician in the long-term management of implants.

    Matched MeSH terms: Dental Prosthesis Design
  10. Chandrasekhar J, Zeebregts D, Kalkman DN, Sartori S, Roumeliotis A, Aquino MB, et al.
    Cardiovasc Revasc Med, 2020 12;21(12):1542-1547.
    PMID: 32507695 DOI: 10.1016/j.carrev.2020.05.002
    BACKGROUND: Small vessel diameter is associated with higher risk of target lesion revascularization (TLR) after percutaneous coronary intervention (PCI). The COMBO sirolimus-eluting biodegradable-polymer stent has a proprietary anti-CD34 antibody layer to enhance homogeneous endothelialization, which may be advantageous in treating small vessels.

    OBJECTIVE: We examined for differences in 1-year clinical outcomes after PCI by maximum implanted stent diameter from the COMBO collaboration.

    METHODS: The COMBO collaboration (n = 3614) is a patient-level pooled dataset of patients undergoing PCI with COMBO stents in the MASCOT and REMEDEE multicenter registries. Stent diameter was available in 3590 (99.3%) patients. We compared patients receiving COMBO stents <3 mm versus ≥3 mm. The primary endpoint was 1-year target lesion failure (TLF), composite of cardiac death, target vessel-myocardial infarction (TV-MI) or clinically driven TLR. Secondary outcomes included stent thrombosis (ST). Adjusted outcomes were assessed using Cox regression methods.

    RESULTS: The study included 792 (22%) patients with small stents <3 mm and 2798 (78%) patients with large stents ≥3 mm. Small stent patients included more women with lower body mass index and higher prevalence of diabetes but similar prevalence of acute coronary syndrome. Risk of 1-year TLF was similar in small and large stent groups (4.4% vs. 3.8%, HR 1.12, 95% CI 0.74-1.72, p = 0.58). There were no differences in the rates of cardiac death (1.7% vs. 1.5%, p = 0.74), TV-MI (1.4% vs. 1.2%, p = 0.58) or TLR (2.7% vs. 2.1%, p = 0.31). Definite or probable ST occurred in 1.3% of the small stent and 0.7% of the large stent PCI patients, p = 0.14, HR 2.13, 95% CI 0.93-5.00, p = 0.07.

    CONCLUSIONS: One-year ischemic outcomes after COMBO PCI were similar irrespective of stent diameter in this all-comers international cohort.

    Matched MeSH terms: Prosthesis Design
  11. Chandrasekhar J, Kalkman DN, Aquino MB, Sartori S, Hájek P, Atzev B, et al.
    Int J Cardiol, 2020 05 15;307:17-23.
    PMID: 32111358 DOI: 10.1016/j.ijcard.2020.01.045
    BACKGROUND: The COMBO drug-eluting stent combines sirolimus-elution from a biodegradable polymer with an anti-CD34+ antibody coating for early endothelialization.

    OBJECTIVE: We investigated for geographical differences in outcomes after percutaneous coronary intervention (PCI) with the COMBO stent among Asians and Europeans.

    METHODS: The COMBO Collaboration is a pooled patient-level analysis of the MASCOT and REMEDEE registries of all-comers undergoing attempted COMBO stent PCI. The primary outcome was 1-year target lesion failure (TLF), composite of cardiac death, target vessel myocardial infarction (TV-MI) and target lesion revascularization (TLR).

    RESULTS: This study included 604 Asians (17.9%) and 2775 Europeans (82.1%). Asians were younger and included fewer females, with a higher prevalence of diabetes mellitus but lower prevalence of other comorbidities than Europeans. Asians had a higher prevalence of ACC/AHA C type lesions and received longer stent lengths. More Asians than Europeans were discharged on clopidogrel (86.5% vs 62.8%) rather than potent P2Y12 inhibitors. One-year TLF occurred in 4.0% Asians and 4.1% of Europeans, p = 0.93. The incidence of cardiac death was higher in Asians (2.8% vs. 1.3%, p = 0.007) with similar rates of TV-MI (1.5% vs. 1.2%, p = 0.54) and definite stent thrombosis (0.3% vs. 0.5%, p = 0.84) and lower incidence of TLR than Europeans (1.0% vs. 2.5%, p = 0.025). After adjustment, differences for cardiac death and TLR were no longer significant.

    CONCLUSIONS: In the COMBO collaboration, although 1-year TLF was similar regardless of geography, Asians experienced higher rates of cardiac death and lower TLR than Europeans, while incidence of TV-MI and ST was similar in both regions. Adjusted differences did not reach statistical significance. CLINICALTRIAL.

    GOV IDENTIFIER-NUMBERS: NCT01874002 (REMEDEE Registry), NCT02183454 (MASCOT registry).

    Matched MeSH terms: Prosthesis Design
  12. Chandrasekhar J, Kerkmeijer LS, Kalkman DN, Sartori S, Aquino MB, Woudstra P, et al.
    Catheter Cardiovasc Interv, 2021 04 01;97(5):797-804.
    PMID: 32198837 DOI: 10.1002/ccd.28853
    BACKGROUND: The COMBO drug eluting stent is a novel device with luminal endothelial progenitor cell capture technology for rapid homogeneous endothelialization.

    METHODS AND RESULTS: We examined for sex differences in 1-year outcomes after COMBO stenting from the COMBO collaboration, a pooled patient-level dataset from the MASCOT and REMEDEE multicenter registries. The primary endpoint was 1-year target lesion failure (TLF), composite of cardiac death, target vessel-myocardial infarction (TV-MI), or clinically driven target lesion revascularization (CD-TLR). Secondary outcomes included stent thrombosis (ST). Adjusted outcomes were assessed using Cox regression methods. The study included 861 (23.8%) women and 2,753 (76.2%) men. Women were older with higher prevalence of several comorbidities including diabetes mellitus. Risk of 1-year TLF was similar in both sexes (3.8% vs. 3.9%, HR 0.92, 95% CI 0.59-1.42, p = .70), without sex differences in the incidence of cardiac death (1.6% vs. 1.5%, p = .78), TV-MI (1.5% vs. 1.1%, p = .32), or CD-TLR (2.0% vs. 2.2%, p = .67). Definite or probable ST occurred in 0.4% women and 1.0% men (HR 0.26, 95% CI 0.06-1.11, p = .069).

    CONCLUSIONS: Despite greater clinical risks at baseline, women treated with COMBO stents had similarly low 1-year TLF and other ischemic outcomes compared to men.

    Matched MeSH terms: Prosthesis Design
  13. Al-Fakih E, Arifin N, Pirouzi G, Mahamd Adikan FR, Shasmin HN, Abu Osman NA
    J Biomed Opt, 2017 Aug;22(8):1-8.
    PMID: 28822140 DOI: 10.1117/1.JBO.22.8.087001
    This paper presents a fiber Bragg grating (FBG)-instrumented prosthetic silicone liner that provides cushioning for the residual limb and can successfully measure interface pressures inside prosthetic sockets of lower-limb amputees in a simple and practical means of sensing. The liner is made of two silicone layers between which 12 FBG sensors were embedded at locations of clinical interest. The sensors were then calibrated using a custom calibration platform that mimics a real-life situation. Afterward, a custom gait simulating machine was built to test the liner performance during an amputee's simulated gait. To validate the findings, the results were compared to those obtained by the commonly used F-socket mats. As the statistical findings reveal, both pressure mapping methods measured the interface pressure in a consistent way, with no significant difference (P-values ≥0.05). This pressure mapping technique in the form of a prosthetic liner will allow prosthetics professionals to quickly and accurately create an overall picture of the interface pressure distribution inside sockets in research and clinical settings, thereby improving the socket fit and amputee's satisfaction.
    Matched MeSH terms: Prosthesis Design
  14. Raj JJ, Thompson M, Whitehouse SL, Jaiprakash A, Varughese I, Crawford RW
    Proc Inst Mech Eng H, 2023 Mar;237(3):368-374.
    PMID: 36734414 DOI: 10.1177/09544119231152351
    Standard practice for acetabular component placement in total hip arthroplasty (THA) is to medialise the acetabular component. Bone preservation techniques during primary THA are beneficial for possible future revisions. The goal of this study is to examine the effect of downsizing and minimising medialisation of the acetabular component on bone resection volume. The volume of bone resected during acetabular preparation for different sizes of components was calculated and the volume of bone preserved by downsizing the cup was determined. Minimising medialisation of the acetabular component by 1-3 mm from the true floor was calculated. Absolute values and percentage of bone volume preserved when acetabular components are downsized or less medialised is presented. Downsizing the acetabular component by one size (2 mm) preserves between 2.6 cm3 (size 40 vs 42) and 8.4 cm3 (size 72 vs 74) of bone volume and consistently reduces resected bone volume by at least 35% (range 35.2%-37.5%). Similarly, reducing medialisation of a 56 mm acetabular cup (as an example of a commonly implanted component) by 3 mm reduces bone loss by 5.9 cm3- 44% less bone volume resection. Downsizing and minimising medialisation of the cup in THA substantially preserves bone which may benefit future revision surgeries. Surgeons could consider implanting the smallest acceptable acetabular shell to preserve bone without compromising on head size.
    Matched MeSH terms: Prosthesis Design
  15. Baharuddin MY, Salleh ShH, Zulkifly AH, Lee MH, Mohd Noor A
    Biomed Res Int, 2014;2014:692328.
    PMID: 25025068 DOI: 10.1155/2014/692328
    A morphology study was essential to the development of the cementless femoral stem because accurate dimensions for both the periosteal and endosteal canal ensure primary fixation stability for the stem, bone interface, and prevent stress shielding at the calcar region. This paper focused on a three-dimensional femoral model for Asian patients that applied preoperative planning and femoral stem design. We measured various femoral parameters such as the femoral head offset, collodiaphyseal angle, bowing angle, anteversion, and medullary canal diameters from the osteotomy level to 150 mm below the osteotomy level to determine the position of the isthmus. Other indices and ratios for the endosteal canal, metaphyseal, and flares were computed and examined. The results showed that Asian femurs are smaller than Western femurs, except in the metaphyseal region. The canal flare index (CFI) was poorly correlated (r < 0.50) to the metaphyseal canal flare index (MCFI), but correlated well (r = 0.66) with the corticomedullary index (CMI). The diversity of the femoral size, particularly in the metaphyseal region, allows for proper femoral stem design for Asian patients, improves osseointegration, and prolongs the life of the implant.
    Matched MeSH terms: Prosthesis Design/methods
  16. Fallahiarezoodar A, Abdul Kadir MR, Alizadeh M, Naveen SV, Kamarul T
    Knee Surg Sports Traumatol Arthrosc, 2014 Dec;22(12):3019-27.
    PMID: 25149643 DOI: 10.1007/s00167-014-3227-7
    PURPOSE: Reproducing the femoral rollback through specially designed mechanism in knee implants is required to achieve full knee function in total knee arthroplasty. Most contemporary implants use cam/post mechanism to replace the function of Posterior Cruciate Ligament. This study was aimed to determine the most appropriate cam and post designs to produce normal femoral rollback of the knee.

    METHODS: Three different cams (triangle, ellipse, and circle) and three different posts (straight, convex, concave) geometries were considered in this study and were analysed using kinematic analyses. Femoral rollback did not occur until reaching 50° of knee flexion. Beyond this angle, two of the nine combinations demonstrate poor knee flexion and were eliminated from the study.

    RESULTS: The combination of circle cam with concave post, straight post and convex post showed 15.6, 15.9 and 16.1 mm posterior translation of the femur, respectively. The use of ellipse cam with convex post and straight post demonstrated a 15.3 and 14.9 mm femoral rollback, whilst the combination of triangle cam with convex post and straight post showed 16.1 and 15.8 mm femoral rollback, respectively.

    CONCLUSION: The present study demonstrates that the use of circle cam and convex post created the best femoral rollback effect which in turn produces the highest amount of knee flexion. The findings of the study suggest that if the design is applied for knee implants, superior knee flexion may be possible for future patients.

    LEVEL OF EVIDENCE: IV.

    Matched MeSH terms: Prosthesis Design*
  17. Abd Razak NA, Abu Osman NA, Kamyab M, Wan Abas WA, Gholizadeh H
    Am J Phys Med Rehabil, 2014 May;93(5):437-44.
    PMID: 24429510 DOI: 10.1097/PHM.0b013e3182a51fc2
    This report compares wrist supination and pronation and flexion and extension movements with the common body-powered prosthesis and a new biomechatronics prosthesis with regard to patient satisfaction and problems experienced with the prosthesis. Fifteen subjects with traumatic transradial amputation who used both prosthetic systems participated in this study. Each subject completed two questionnaires to evaluate their satisfaction and problems experienced with the two prosthetic systems. Satisfaction and problems with the prosthetic's wrist movements were analyzed in terms of the following: supination and pronation; flexion and extension; appearance; sweating; wounds; pain; irritation; pistoning; smell; sound; durability; and the abilities to open a door, hold a cup, and pick up or place objects. This study revealed that the respondents were more satisfied with the biomechatronics wrist prosthesis with regard to supination and pronation, flexion and extension, pain, and the ability to open a door. However, satisfaction with the prosthesis showed no significant differences in terms of sweating, wounds, irritation, pistoning, smell, sound, and durability. The abilities to hold a cup and pick up or place an object were significantly better with the body-powered prosthesis. The results of the survey suggest that satisfaction and problems with wrist movements in persons with transradial amputation can be improved with a biomechatronics wrist prosthesis compared with the common body-powered prosthesis.
    Matched MeSH terms: Prosthesis Design*
  18. Ishak MI, Kadir MR, Sulaiman E, Kasim NH
    Int J Oral Maxillofac Implants, 2013 May-Jun;28(3):e151-60.
    PMID: 23748334 DOI: 10.11607/jomi.2304
    To compare the extramaxillary approach with the widely used intrasinus approach via finite element method.
    Matched MeSH terms: Dental Prosthesis Design/methods*
  19. Saidin S, Abdul Kadir MR, Sulaiman E, Abu Kasim NH
    J Dent, 2012 Jun;40(6):467-74.
    PMID: 22366313 DOI: 10.1016/j.jdent.2012.02.009
    The aim of this study was to analyse micromotion and stress distribution at the connections of implants and four types of abutments: internal hexagonal, internal octagonal, internal conical and trilobe.
    Matched MeSH terms: Dental Prosthesis Design*
  20. Ishak MI, Abdul Kadir MR, Sulaiman E, Abu Kasim NH
    Int J Oral Maxillofac Surg, 2012 Sep;41(9):1077-89.
    PMID: 22575179 DOI: 10.1016/j.ijom.2012.04.010
    The aim of this study was to compare two different types of surgical approaches, intrasinus and extramaxillary, for the placement of zygomatic implants to treat atrophic maxillae. A computational finite element simulation was used to analyze the strength of implant anchorage for both approaches in various occlusal loading locations. Three-dimensional models of the craniofacial structures surrounding a region of interest, soft tissue and framework were developed using computed tomography image datasets. The implants were modelled using computer-aided design software. The bone was assumed to be linear isotropic with a stiffness of 13.4 GPa, and the implants were assumed to be made of titanium with a stiffness of 110 GPa. Masseter forces of 300 N were applied at the zygomatic arch, and occlusal loads of 150 N were applied vertically onto the framework surface at different locations. The intrasinus approach demonstrated more satisfactory results and could be a viable treatment option. The extramaxillary approach could also be recommended as a reasonable treatment option, provided some improvements are made to address the cantilever effects seen with that approach.
    Matched MeSH terms: Dental Prosthesis Design/methods*
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links