The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Rsb Liem - One of the best experts on this subject based on the ideXlab platform.
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wear testing of a temporomandibular Joint Prosthesis uhmwpe and ptfe against a metal ball in water and in serum
Biomaterials, 1999Co-Authors: J P Van Loon, Lambert G.m. De Bont, Gijsbertus Jacob Verkerke, Rsb LiemAbstract:For a temporomandibular Joint Prosthesis, an estimation of the wear rate was needed, prior to patient application. Therefore, we determined the in vitro wear rate of the ball-socket articulation of this Prosthesis, consisting of a metal head and an ultra-high molecular weight polyethylene (UHMWPE) cup. The basic testing configuration consisted of one 8-mm diameter stainless-steel ball, rotating between two conforming cups with a minimum thickness of 5 mm. For validation of the testing apparatus, two cup materials, in two lubricants, were tested. Both cup materials, UHMWPE and polytetrafluoroethylene (PTFE) were tested in deionized water, as well as in a serum-based solution. For UHMWPE in serum, eight samples were tested, for the other combinations four samples. For UHMWPE, the tests ran for 7 million cycles, for PTFE between 0.8 and 1.7 million cycles. For UHMWPE, the wear rate was 0.006 and 0.47 (mm(3)/10(6) cycles), in water and in serum, respectively. For PTFE, the wear rate was 2.8 and 47 (mm(3)/10(6) cycles), in water and in serum, respectively. For reason that testing in serum simulates the in vivo situation best, it was concluded that the wear rate of the TMJ Prosthesis articulation is 0.47 (mm(3)/10(6) cycles), which is considered acceptable. (C) 1999 Elsevier Science Ltd. All rights reserved.
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Wear-testing of a temporomandibular Joint Prosthesis: UHMWPE and PTFE against a metal ball, in water and in serum.
Biomaterials, 1999Co-Authors: J.-p. Van Loon, Gijsbertus Jacob Verkerke, L.g.m. De Bont, Rsb LiemAbstract:For a temporomandibular Joint Prosthesis, an estimation of the wear rate was needed, prior to patient application. Therefore, we determined the in vitro wear rate of the ball-socket articulation of this Prosthesis, consisting of a metal head and an ultra-high molecular weight polyethylene (UHMWPE) cup. The basic testing configuration consisted of one 8-mm diameter stainless-steel ball, rotating between two conforming cups with a minimum thickness of 5 mm. For validation of the testing apparatus, two cup materials, in two lubricants, were tested. Both cup materials, UHMWPE and polytetrafluoroethylene (PTFE) were tested in deionized water, as well as in a serum-based solution. For UHMWPE in serum, eight samples were tested, for the other combinations four samples. For UHMWPE, the tests ran for 7 million cycles, for PTFE between 0.8 and 1.7 million cycles. For UHMWPE, the wear rate was 0.006 and 0.47 (mm3/10(6) cycles), in water and in serum, respectively. For PTFE, the wear rate was 2.8 and 47 (mm3/10(6) cycles), in water and in serum, respectively. For reason that testing in serum simulates the in vivo situation best, it was concluded that the wear rate of the TMJ Prosthesis articulation is 0.47 (mm3/10(6) cycles), which is considered acceptable.
Gijsbertus Jacob Verkerke - One of the best experts on this subject based on the ideXlab platform.
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design and wear testing of a temporomandibular Joint Prosthesis articulation
Journal of Dental Research, 2000Co-Authors: J P Van Loon, M P De Vries, Gijsbertus Jacob Verkerke, Lambert G.m. De BontAbstract:As part of the development of a total temporomandibular Joint Prosthesis, a Prosthesis articulation was designed. The articulation consists of a spherical head (ball) of the mandibular part, rotating against an enveloping ultra-high-molecular-weight polyethylene (UHMWPE) disc with a flat cranial side, which slides along the opposing skull part. The aim of this study was to determine the in vitro wear rate of the articulation, and to predict the in vivo wear rate from the results. Based on a disc thickness of 5 mm and a ball diameter of 8 mm, the stresses within the disc were calculated by means of a finite element computer model. The wear rate of the ball-disc articulation was determined by in vitro wear tests, with a stainless-steel ball rotating against a UHMWPE disc in a serum-based lubricant. Eight discs were tested for seven million cycles each. The in vitro wear rate of the disc-skull part articulation was calculated from the test results of the ball-disc articulation. The maximum Von Mises' stress ...
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wear testing of a temporomandibular Joint Prosthesis uhmwpe and ptfe against a metal ball in water and in serum
Biomaterials, 1999Co-Authors: J P Van Loon, Lambert G.m. De Bont, Gijsbertus Jacob Verkerke, Rsb LiemAbstract:For a temporomandibular Joint Prosthesis, an estimation of the wear rate was needed, prior to patient application. Therefore, we determined the in vitro wear rate of the ball-socket articulation of this Prosthesis, consisting of a metal head and an ultra-high molecular weight polyethylene (UHMWPE) cup. The basic testing configuration consisted of one 8-mm diameter stainless-steel ball, rotating between two conforming cups with a minimum thickness of 5 mm. For validation of the testing apparatus, two cup materials, in two lubricants, were tested. Both cup materials, UHMWPE and polytetrafluoroethylene (PTFE) were tested in deionized water, as well as in a serum-based solution. For UHMWPE in serum, eight samples were tested, for the other combinations four samples. For UHMWPE, the tests ran for 7 million cycles, for PTFE between 0.8 and 1.7 million cycles. For UHMWPE, the wear rate was 0.006 and 0.47 (mm(3)/10(6) cycles), in water and in serum, respectively. For PTFE, the wear rate was 2.8 and 47 (mm(3)/10(6) cycles), in water and in serum, respectively. For reason that testing in serum simulates the in vivo situation best, it was concluded that the wear rate of the TMJ Prosthesis articulation is 0.47 (mm(3)/10(6) cycles), which is considered acceptable. (C) 1999 Elsevier Science Ltd. All rights reserved.
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Wear-testing of a temporomandibular Joint Prosthesis: UHMWPE and PTFE against a metal ball, in water and in serum.
Biomaterials, 1999Co-Authors: J.-p. Van Loon, Gijsbertus Jacob Verkerke, L.g.m. De Bont, Rsb LiemAbstract:For a temporomandibular Joint Prosthesis, an estimation of the wear rate was needed, prior to patient application. Therefore, we determined the in vitro wear rate of the ball-socket articulation of this Prosthesis, consisting of a metal head and an ultra-high molecular weight polyethylene (UHMWPE) cup. The basic testing configuration consisted of one 8-mm diameter stainless-steel ball, rotating between two conforming cups with a minimum thickness of 5 mm. For validation of the testing apparatus, two cup materials, in two lubricants, were tested. Both cup materials, UHMWPE and polytetrafluoroethylene (PTFE) were tested in deionized water, as well as in a serum-based solution. For UHMWPE in serum, eight samples were tested, for the other combinations four samples. For UHMWPE, the tests ran for 7 million cycles, for PTFE between 0.8 and 1.7 million cycles. For UHMWPE, the wear rate was 0.006 and 0.47 (mm3/10(6) cycles), in water and in serum, respectively. For PTFE, the wear rate was 2.8 and 47 (mm3/10(6) cycles), in water and in serum, respectively. For reason that testing in serum simulates the in vivo situation best, it was concluded that the wear rate of the TMJ Prosthesis articulation is 0.47 (mm3/10(6) cycles), which is considered acceptable.
Lambert G.m. De Bont - One of the best experts on this subject based on the ideXlab platform.
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design and wear testing of a temporomandibular Joint Prosthesis articulation
Journal of Dental Research, 2000Co-Authors: J P Van Loon, M P De Vries, Gijsbertus Jacob Verkerke, Lambert G.m. De BontAbstract:As part of the development of a total temporomandibular Joint Prosthesis, a Prosthesis articulation was designed. The articulation consists of a spherical head (ball) of the mandibular part, rotating against an enveloping ultra-high-molecular-weight polyethylene (UHMWPE) disc with a flat cranial side, which slides along the opposing skull part. The aim of this study was to determine the in vitro wear rate of the articulation, and to predict the in vivo wear rate from the results. Based on a disc thickness of 5 mm and a ball diameter of 8 mm, the stresses within the disc were calculated by means of a finite element computer model. The wear rate of the ball-disc articulation was determined by in vitro wear tests, with a stainless-steel ball rotating against a UHMWPE disc in a serum-based lubricant. Eight discs were tested for seven million cycles each. The in vitro wear rate of the disc-skull part articulation was calculated from the test results of the ball-disc articulation. The maximum Von Mises' stress ...
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wear testing of a temporomandibular Joint Prosthesis uhmwpe and ptfe against a metal ball in water and in serum
Biomaterials, 1999Co-Authors: J P Van Loon, Lambert G.m. De Bont, Gijsbertus Jacob Verkerke, Rsb LiemAbstract:For a temporomandibular Joint Prosthesis, an estimation of the wear rate was needed, prior to patient application. Therefore, we determined the in vitro wear rate of the ball-socket articulation of this Prosthesis, consisting of a metal head and an ultra-high molecular weight polyethylene (UHMWPE) cup. The basic testing configuration consisted of one 8-mm diameter stainless-steel ball, rotating between two conforming cups with a minimum thickness of 5 mm. For validation of the testing apparatus, two cup materials, in two lubricants, were tested. Both cup materials, UHMWPE and polytetrafluoroethylene (PTFE) were tested in deionized water, as well as in a serum-based solution. For UHMWPE in serum, eight samples were tested, for the other combinations four samples. For UHMWPE, the tests ran for 7 million cycles, for PTFE between 0.8 and 1.7 million cycles. For UHMWPE, the wear rate was 0.006 and 0.47 (mm(3)/10(6) cycles), in water and in serum, respectively. For PTFE, the wear rate was 2.8 and 47 (mm(3)/10(6) cycles), in water and in serum, respectively. For reason that testing in serum simulates the in vivo situation best, it was concluded that the wear rate of the TMJ Prosthesis articulation is 0.47 (mm(3)/10(6) cycles), which is considered acceptable. (C) 1999 Elsevier Science Ltd. All rights reserved.
J P Van Loon - One of the best experts on this subject based on the ideXlab platform.
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design and wear testing of a temporomandibular Joint Prosthesis articulation
Journal of Dental Research, 2000Co-Authors: J P Van Loon, M P De Vries, Gijsbertus Jacob Verkerke, Lambert G.m. De BontAbstract:As part of the development of a total temporomandibular Joint Prosthesis, a Prosthesis articulation was designed. The articulation consists of a spherical head (ball) of the mandibular part, rotating against an enveloping ultra-high-molecular-weight polyethylene (UHMWPE) disc with a flat cranial side, which slides along the opposing skull part. The aim of this study was to determine the in vitro wear rate of the articulation, and to predict the in vivo wear rate from the results. Based on a disc thickness of 5 mm and a ball diameter of 8 mm, the stresses within the disc were calculated by means of a finite element computer model. The wear rate of the ball-disc articulation was determined by in vitro wear tests, with a stainless-steel ball rotating against a UHMWPE disc in a serum-based lubricant. Eight discs were tested for seven million cycles each. The in vitro wear rate of the disc-skull part articulation was calculated from the test results of the ball-disc articulation. The maximum Von Mises' stress ...
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wear testing of a temporomandibular Joint Prosthesis uhmwpe and ptfe against a metal ball in water and in serum
Biomaterials, 1999Co-Authors: J P Van Loon, Lambert G.m. De Bont, Gijsbertus Jacob Verkerke, Rsb LiemAbstract:For a temporomandibular Joint Prosthesis, an estimation of the wear rate was needed, prior to patient application. Therefore, we determined the in vitro wear rate of the ball-socket articulation of this Prosthesis, consisting of a metal head and an ultra-high molecular weight polyethylene (UHMWPE) cup. The basic testing configuration consisted of one 8-mm diameter stainless-steel ball, rotating between two conforming cups with a minimum thickness of 5 mm. For validation of the testing apparatus, two cup materials, in two lubricants, were tested. Both cup materials, UHMWPE and polytetrafluoroethylene (PTFE) were tested in deionized water, as well as in a serum-based solution. For UHMWPE in serum, eight samples were tested, for the other combinations four samples. For UHMWPE, the tests ran for 7 million cycles, for PTFE between 0.8 and 1.7 million cycles. For UHMWPE, the wear rate was 0.006 and 0.47 (mm(3)/10(6) cycles), in water and in serum, respectively. For PTFE, the wear rate was 2.8 and 47 (mm(3)/10(6) cycles), in water and in serum, respectively. For reason that testing in serum simulates the in vivo situation best, it was concluded that the wear rate of the TMJ Prosthesis articulation is 0.47 (mm(3)/10(6) cycles), which is considered acceptable. (C) 1999 Elsevier Science Ltd. All rights reserved.
Larry M Wolford - One of the best experts on this subject based on the ideXlab platform.
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successful reconstruction of nongrowing hemifacial microsomia patients with unilateral temporomandibular Joint total Joint Prosthesis and orthognathic surgery
Journal of Oral and Maxillofacial Surgery, 2012Co-Authors: Larry M Wolford, Daniel B Rodrigues, Campbell T Bourland, Daniel Perez, Evelin LimoeiroAbstract:Purpose Traditionally, patients with hemifacial microsomia (HFM) and significant ipsilateral hypoplasia or absence of the condyle and ramus undergo reconstruction on the ipsilateral side with autogenous tissues such as rib grafts, often with compromised results. This study analyzed the surgical treatment outcomes of nongrowing patients with HFM and reconstruction of the ipsilateral temporomandibular Joint (TMJ) and advancement of the mandible with a patient-fitted TMJ total Joint Prosthesis (TMJ Concepts, Inc, Ventura, CA), a contralateral mandibular ramus sagittal split osteotomy, and maxillary osteotomies performed in 1 operation. Patients and Methods All nongrowing patients with HFM treated with this surgical protocol from 1997 to 2010 in a single private practice were included in this study and subjectively evaluated before surgery and at the longest postsurgical follow-up for pain, diet, jaw function, and disability using a visual numerical scale (0 to 10). Surgical changes and postsurgical stability were analyzed using lateral cephalograms before surgery, immediately after surgery, and at the longest follow-up. Results Six patients (4 female and 2 male) were included in this study, with an average age at surgery of 23.5 years (range, 14 to 39 yrs) and an average follow-up of 6 years 3 months (range, 1 yr to 11 yrs 4 mo). For all subjective parameters, all patients improved or remained the same. Incisal opening improved or remained the same in 4 of the 6 patients, with 2 patients having decreased opening. Excursive movements decreased. The maxillomandibular complex was surgically rotated counterclockwise, advanced, and transversely leveled, with the anterior maxillary reference points (anterior nasal spine, point A) undergoing relative small movements. The mandibular incisor tips (lower incisor tips) advanced a mean of 8.9 mm, point B 14.8 mm, pogonion 18.6 mm, menton 17.5 mm and the occlusal plane angle decreased −12.3°. Postsurgical long-term stability indicated that the anterior maxillary references changed a significant amount, whereas all horizontal and vertical anterior mandibular measurements (lower incisor tip, point B, pogonion, menton) and the occlusal plane showed no significant changes. Conclusions The TMJ Concepts total Joint Prosthesis in conjunction with orthognathic surgery for TMJ and jaw reconstruction in nongrowing patients with HFM is highly predictable for skeletal and occlusal stability, comfort, TMJ function, and improved facial balance.
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management of the infected temporomandibular Joint total Joint Prosthesis
Journal of Oral and Maxillofacial Surgery, 2010Co-Authors: Larry M Wolford, Daniel B Rodrigues, Andrea McphillipsAbstract:Purpose Patients with specific temporomandibular Joint (TMJ) conditions and pathology may benefit from TMJ reconstruction by use of total Joint prostheses. A potential risk to patients receiving TMJ total Joint prostheses is infection. The purpose of this study was to present our experience in treating infected TMJ total Joint prostheses over a 12-year period, as well as the protocol we have developed to manage acute infections and the protocol we follow for chronic infections of TMJ total Joint prostheses. Patients and Methods This retrospective study evaluated the records of 316 consecutive patients (290 female and 26 male patients) who had TMJ reconstruction from 1997 to 2009 by 1 surgeon, using patient-fitted TMJ Concepts total Joint prostheses (TMJ Concepts, Ventura, CA), with a total of 579 prostheses placed, to determine the occurrence and management methods of postoperative infections. Postoperative infections involving the TMJ prostheses developed in 8 of 316 patients (2.5%) and 9 of 579 prostheses (1.6%): 7 patients unilaterally and 1 patient bilaterally. Patients were divided into 2 groups: group 1 (n = 5) had acute infections in 6 Joints and group 2 (n = 3) had chronic infections in 3 Joints. Patient 5 began in group 1 but was transferred to group 2. One patient with Munchausen syndrome and self-induced infections was eliminated from the study. Patients were treated by our protocol for management of acute or chronic infections. Results In group 1 (n = 5) the onset of infection symptoms averaged 12 days after surgery (range, 5-24 days). The time from onset of symptoms to surgical intervention was 3.4 days (range, 2-5 days). We found that 4 of 5 patients (80%) and 5 of 6 Joints (83%) were successfully treated with retention of the prostheses. Patient 5 varied from the protocol and maintained a chronic infection of her right TMJ Prosthesis that transferred her to group 2. In group 2 (n = 3) all 3 patients (including patient 5) had chronic infections with draining fistulas that were successfully treated by the chronic infection protocol including Prosthesis removal and replacement. Conclusions TMJ total Joint prostheses can become infected. The earlier the diagnosis is made and the acute infection protocol initiated (within 2-5 days), the greater the chance of salvage of the Prosthesis. For chronic infections, the treatment protocol has likewise been very successful, but it does require 2 surgical stages for removal and replacement of the Prosthesis. Management of infected total Joint Prosthesis can be challenging, but with aggressive treatment following the appropriate protocol, infected prostheses can be successfully managed.
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tmj concepts techmedica custom made tmj total Joint Prosthesis 5 year follow up study
International Journal of Oral and Maxillofacial Surgery, 2003Co-Authors: Larry M Wolford, M.c. Pitta, O Reichefischel, P.f. FrancoAbstract:This prospective study evaluated the 5 to 8 year subjective and objective results of 42 consecutive patients who had TMJ reconstruction using the TMJ Concepts/Techmedica custom made total Joint Prosthesis. Criteria for use of the Prosthesis included the following TMJ conditions: (1) multiply operated, (2) previous alloplastic implants, (3) osteoarthritis, (4) inflammatory or resorptive arthritis, (5) connective tissue or autoimmune disease, (6) ankylosis, and (7) absent or deformed structures. Thirty-eight of 42 patients (90%) with 69 TMJs reconstructed using the TMJ Concepts/Techmedica total Joint Prosthesis had appropriate data for inclusion in the study. The average age at surgery was 36 years and average follow-up was 73.5 months. The entire group and three subgroups were objectively evaluated for incisal opening, lateral excursions, and occlusal stability, while subjectively assessed for pain and jaw function. Paired t-test and comparison analyses were used to assess outcomes. For the group of 38 patients, there was statistically significant improvement in incisal opening (P=0.001), jaw function (P=0.001), and pain level (P=0.0001). Lateral excursion movements significantly decreased (P=0.04). The occlusion remained stable in all cases. Complications occurred in six patients. Comparison analysis of the three groups demonstrated significantly better outcomes for patients with fewer previous TMJ surgeries and without exposure to Proplast-Teflon or Silastic TMJ implants. This study demonstrated that the TMJ Concepts/Techmedica total Joint Prosthesis is a viable technique for TMJ reconstruction as a primary procedure and for patients with previous multiple TMJ surgeries and mutilated anatomy of the TMJ.
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TMJ Concepts/Techmedica custom-made TMJ total Joint Prosthesis: 5-year follow-up study
International journal of oral and maxillofacial surgery, 2003Co-Authors: Larry M Wolford, M.c. Pitta, O. Reiche-fischel, P.f. FrancoAbstract:This prospective study evaluated the 5 to 8 year subjective and objective results of 42 consecutive patients who had TMJ reconstruction using the TMJ Concepts/Techmedica custom made total Joint Prosthesis. Criteria for use of the Prosthesis included the following TMJ conditions: (1) multiply operated, (2) previous alloplastic implants, (3) osteoarthritis, (4) inflammatory or resorptive arthritis, (5) connective tissue or autoimmune disease, (6) ankylosis, and (7) absent or deformed structures. Thirty-eight of 42 patients (90%) with 69 TMJs reconstructed using the TMJ Concepts/Techmedica total Joint Prosthesis had appropriate data for inclusion in the study. The average age at surgery was 36 years and average follow-up was 73.5 months. The entire group and three subgroups were objectively evaluated for incisal opening, lateral excursions, and occlusal stability, while subjectively assessed for pain and jaw function. Paired t-test and comparison analyses were used to assess outcomes. For the group of 38 patients, there was statistically significant improvement in incisal opening (P=0.001), jaw function (P=0.001), and pain level (P=0.0001). Lateral excursion movements significantly decreased (P=0.04). The occlusion remained stable in all cases. Complications occurred in six patients. Comparison analysis of the three groups demonstrated significantly better outcomes for patients with fewer previous TMJ surgeries and without exposure to Proplast-Teflon or Silastic TMJ implants. This study demonstrated that the TMJ Concepts/Techmedica total Joint Prosthesis is a viable technique for TMJ reconstruction as a primary procedure and for patients with previous multiple TMJ surgeries and mutilated anatomy of the TMJ.
