Temporomandibular Joint Implants Research Articles

Allostatic load is elevated in subgroups of TMD pain population

Temporomandibular disorders (TMD) are a group of painful musculoskeletal conditions that have been associated with chronic exposure to stress. Allostatic load measures stress-related cumulative strain on multiple organ-systems, particularly on cardiovascular, metabolic, neuroendocrine and immunological systems. Due to the heterogeneity of TMD population, assessing allostatic load among TMD patients may facilitate diagnosis and treatment selection. The current study 1) used Ward hierarchical cluster analysis to sub-classify a group of National Institute of Dental and Craniofacial Research's Temporomandibular Joint Implant Registry and Repository (TIRR) participants (n= 98) who were diagnosed with TMD pain (i.e., arthralgia and/or myalgia based on Research Diagnostic Criteria for TMD); and 2) compared allostatic load between TMD clusters and 120 TIRR participants of non-TMD controls.

ASK THE EXPERTS: Ensuring Accurate Diagnosis of Orofacial Pain Disorders

Dr Fricton received his BS and DDS degree from the University of Iowa (IA, USA), and then undertook his postgraduate studies, completing an MS in Oral Biology at UCLA School of Dentistry (University of California, CA, USA) and an Anesthesiology and Pain Management Residency at UCLA Medical Center. After research and clinical training at UCLA, he joined the faculty at the University of Minnesota (MN, USA), where he is currently a Professor in the Department of Diagnostic and Surgical Sciences and Physical Medicine and Rehabilitation. He is also a Senior Research Investigator at HealthPartners Research Foundation (MN, USA). He has over 30 years experience in clinical care, research and teaching in the field of chronic pain, orofacial pain, temporomandibular muscle and joint disorders, muscle pain, and, more recently, health informatics. His sponsored research has focused on epidemiological studies and clinical trials of therapeutic strategies for chronic pain conditions. He has developed a biobehavioral framework for personalized care for chronic pain conditions and has integrated this pain research with studies of health information technology, focusing on the use of electronic health records, personal health records and clinical decision support to improve the outcomes and quality of healthcare. He is Principal Investigator for the NIH NIDCR's temporomandibular joint (TMJ) Implant Registry and Repository, which includes research into the genetic, biomechanical and biobehavioral factors involved in the success or failure of TMJ implants. In addition, he has served on the governing board of the American Pain Society, and was president of both the American Board of Orofacial Pain and the American Academy of Orofacial Pain. He maintains an active private practice for patients with TMJ, orofacial, head and neck pain in Plymouth (MN, USA) and St Paul (MN, USA).

Influence of Thickness and Contact Surface Geometry of Condylar Stem of TMJ Implant on Its Stability

The aim of this study is to examine the effect thickness and contact surface geometry of condylar stem of TMJ implant on its stability in total reconstruction system and evaluate the micro strain resulted in bone at fixation screw holes in jaw bone embedded with eight different designs of temporomandibular joint implants. A three dimensional model of a lower mandible of an adult were developed from a Computed Tomography scan images. Eight different TMJ implant designs and fixation screws were modeled. Three dimensional finite element models of eight implanted mandibles were analyzed. The forces assigned to the masticatory muscles for incisal clenching were applied consisting of nine important muscular loads. In chosen loading condition, The results indicated that the anatomical curvature contact surface design of TMJ implant can moderately improve the stability and the strain resulted in fixation screw holes in thinner TMJ implant was diminished in comparison with other thicknesses.

Changes in pain and mouth opening at 1 year following temporomandibular joint replacement—a prospective study

We describe the outcome of 46 patients 12 months after partial or total replacement of the temporomandibular joint (TMJ) using the Christensen implant system (TMJ Implants Inc, Golden, CO, USA). The study group comprised 35 women and 11 men; the women were slightly older than the men at the time of operation. We studied three diagnostic groups in detail: patients who had ankylosis, internal derangement, and osteoarthritis. Those with ankylosis were slightly older than the others. Pain decreased over time in all three groups. There was a significant reduction between preoperative pain and that recorded 1 month postoperatively. After this point the pain decreased slowly, and by year 1 it had decreased significantly with respect to preoperative scores. Women reported worse preoperative pain than men, but not significantly so.

Current computational modelling trends in craniomandibular biomechanics and their clinical implications

Computational models of interactions in the craniomandibular apparatus are used with increasing frequency to study biomechanics in normal and abnormal masticatory systems. Methods and assumptions in these models can be difficult to assess by those unfamiliar with current practices in this field; health professionals are often faced with evaluating the appropriateness, validity and significance of models which are perhaps more familiar to the engineering community. This selective review offers a foundation for assessing the strength and implications of a craniomandibular modelling study. It explores different models used in general science and engineering and focuses on current best practices in biomechanics. The problem of validation is considered at some length, because this is not always fully realisable in living subjects. Rigid-body, finite element and combined approaches are discussed, with examples of their application to basic and clinically relevant problems. Some advanced software platforms currently available for modelling craniomandibular systems are mentioned. Recent studies of the face, masticatory muscles, tongue, craniomandibular skeleton, temporomandibular joint, dentition and dental implants are reviewed, and the significance of non-linear and non-isotropic material properties is emphasised. The unique challenges in clinical application are discussed, and the review concludes by posing some questions which one might reasonably expect to find answered in plausible modelling studies of the masticatory apparatus.

Biomechanical Analysis Comparing Natural and Alloplastic Temporomandibular Joint Replacement Using a Finite Element Model

Prosthetic materials and bone present quite different mechanical properties. Consequently, mandible reconstruction with metallic materials (or a mandible condyle implant) modifies the physiologic behavior of the mandible (stress, strain patterns, and condyle displacements). The changing of bone strain distribution results in an adaptation of the temporomandibular joint, including articular contacts. Using a validated finite element model, the natural mandible strains and condyle displacements were evaluated. Modifications of strains and displacements were then assessed for 2 different temporomandibular joint implants. Because materials and geometry play important key roles, mechanical properties of cortical bone were taken into account in models used in finite element analysis. The finite element model allowed verification of the worst loading configuration of the mandibular condyle. Replacing the natural condyle by 1 of the 2 tested implants, the results also show the importance of the implant geometry concerning biomechanical mandibular behavior. The implant geometry and stiffness influenced mainly strain distribution. The different forces applied to the mandible by the elevator muscles, teeth, and joint loads indicate that the finite element model is a relevant tool to optimize implant geometry or, in a subsequent study, to choose a more suitable distribution of the screws. Bone screws (number and position) have a significant influence on mandibular behavior and on implant stress pattern. Stress concentration and implant fracture must be avoided.

Temporomandibular Joint: Disorders, Treatments, and Biomechanics

Temporomandibular joint (TMJ) is a complex, sensitive, and highly mobile joint. Millions of people suffer from temporomandibular disorders (TMD) in USA alone. The TMD treatment options need to be looked at more fully to assess possible improvement of the available options and introduction of novel techniques. As reconstruction with either partial or total joint prosthesis is the potential treatment option in certain TMD conditions, it is essential to study outcomes of the FDA approved TMJ implants in a controlled comparative manner. Evaluating the kinetics and kinematics of the TMJ enables the understanding of structure and function of normal and diseased TMJ to predict changes due to alterations, and to propose more efficient methods of treatment. Although many researchers have conducted biomechanical analysis of the TMJ, many of the methods have certain limitations. Therefore, a more comprehensive analysis is necessary for better understanding of different movements and resulting forces and stresses in the joint components. This article provides the results of a state-of-the-art investigation of the TMJ anatomy, TMD, treatment options, a review of the FDA approved TMJ prosthetic devices, and the TMJ biomechanics.

Custom TMJ Hemi-joint Fabrication Process

Temporomandibular joint disorder afflicts 10 million Americans, many of whom have osteoarthritis of the temporomandibular joint (TMJ). This condition can inflict severe pain and disrupt the lives of sufferers in many ways. Partial or total replacement of the temporomandibular joint is a last resort treatment option. Surgeons at Mayo Clinic believe a new hemijoint implant design coupled with unique surgical technique can improve joint kinematics and reduce pain. They are currently investigating a patent-pending implant design in a series of patient trials. The Division of Engineering at Mayo Clinic has developed a novel process for fabricating TMJ implants for this study. Computed Tomagraphy (CT) images of the surgical site are first converted into a 3D computer model of the mandibular fossa and condyle area. A fused deposition modeling process is used to create a plastic model of the anatomy, and the surgeons use that model to create a wax mold of the implant. The wax mold is laser scanned to create a 3D CAD model that can be machined with a standard four axis milling machine out of implant grade CoCrMo material. Because of the unique shape of the implant, the machining takes place in two phases, with the implant being refixtured between machining phases using a high strength industrial adhesive. Finally, the implant is polished, inspected, passivated and sterilized for surgery. This fabrication process has allowed Mayo Clinic surgeons to quickly and accurately test their unique implant design.

Temporomandibular joint reconstruction after failed teflon-proplast implant: case report and literature review

Multiple reports document that a foreign-body giant cell reaction forms around Proplast-Teflon temporomandibular joint (TMJ) implants. This results in destruction of surrounding bone and instability of the implants. This case presents a patient whose Proplast-Teflon TMJ implants became displaced into her middle cranial fossa. The staged reconstruction of this patient is described, including removal of the TMJ implants, reconstruction of the defect, concomitant orthodontic treatment and final reconstruction with TMJ Concepts ®. This process involved a multidisciplinary approach between several medical and dental specialties. At her 3-year follow up, the patient had a stable postoperative result.

Exuberant Foreign Body Giant Cell Reaction to a Teflon/Proplast Temporomandibular Joint Implant: Report of a Case

Foreign body giant cell reaction to Teflon/Proplast temporomandibular joint (TMJ) implants is a well-known phenomenon. Teflon/Proplast implants were popular in the early 1980s for use in interpositional meniscus replacement after discectomy to maintain vertical dimension and prevent degenerative changes of the condyle. They were also used as part of Vitek-1 and Vitek-2 TMJ replacement prostheses (bioMerieux Inc, Durham, NC). Teflon, or polytetrafluoroethylene (PTFE), is a resilient nonporous material that was placed against the articulating surface of the condyle. Proplast, a PTFE variant that exists in 2 forms (Proplast-1 and Proplast-2), lined the undersurface of the Teflon, and its porous structure promoted tissue ingrowth for incorporation of the implant. Unfortunately, under continuous function, the Teflon/Proplast fragmented and caused an intense foreign body giant cell reaction. We report here a case of exuberant soft tissue proliferation in response to a Teflon/Proplast implant 21 years after placement.

Profilometric Surface Roughness Analysis of Christensen Metal Temporomandibular Joint Prostheses

Functional impairment affecting the quality of life results when a wide range of both muscular and joint pathologies affect the temporomandibular joint (TMJ). Alloplastic reconstruction of joints using Christensen metal TMJ implants have been used since the 1960s for many such patients. To ensure the longevity of such TMJ prostheses, the wear rate of such implants should be minimal. Because surface roughness is an important factor that influences the wear rate, in this study we measured the surface roughness of the condylar and the fossa elements of the new and retrieved Christensen metal TMJ prostheses using the noncontacting optical interferometer (ZYGO-New View 5000). The roughness parameters of the retrieved specimens were statistically higher (p < 0.05) than those for the new specimens, but were less than the retrieved metal total knee implants as reported in the literature.

P.125 Severe resorption of a condyle after open reduction to a displaced condylar fracture

Background and objective: Treatment of temporomandibular joint ankylosis is a challenge and suffers from a high incidence of recurrence. Although treatment of ankylosis has been tried as early as nearly 200 years ago, no single technique produced satisfactory results. An alternative technique and a modified spacer system are described in this paper. Material and methods: Fifteen patients, nine of whom had unilateral and the remaining six had bilateral ankylosis were evaluated. Modified fossa implants were used in all cases. Results: The highest incidence of ankylosis was observed in the 11–20 year age group (nine patients). Falls during childhood was the common aetiological factor. Eight patients had been previously operated upon. Postoperative interinsicial opening values were remarkably different from the preoperative ones and the long-term results were satisfactory. Conclusion: With continued research and development in the treatment of ankylosis, temporomandibular joint implants will become more predictable and reliable. This specially designed fossa implant seems to be promising in the treatment of TMJ ankylosis.

O.062 Biocompatibility of diamond-like carbon coatings for titanium temporomandibular joint implants

O.062 Biocompatibility of diamond-like carbon coatings for titanium temporomandibular joint implants

Temporomandibular Joint Disorders: Artificial Joint Replacements and Future Research Needs

Temporomandibular disorders (TMD) affect a significant section of the American population. According to the National Institutes of Health (NIH), an estimated 3% to 5% of Americans suffer from temporomandibular disorders. Majority of TMDs can be treated by conservative methods, albeit surgical interventions are indicated for some pathological/clinical conditions (according to the American Association of Temporomandibular Joint Surgeons). A distinction can be made between the TMD and the TMJ disease/dysfunction. In the case of TMD, it most correctly relates to a neuromuscular type of problem in the general area of the Temporomandibular Joint (TMJ), but may not intrinsically be related to the TM joint itself. However, TMJ disease/dysfunction relates to a true joint type of pathology, which ultimately may lead to the use of either a partial or a total joint reconstruction. Degeneration of the meniscus and the actual bony portions of the joint is often seen in cases of true TMJ pathology. The use of custom made or predesigned partial and/or total artificial TMJ replacement remains one of the surgical alternatives for treating various TMJ diseases when other conservative treatments fail. The purpose of this article is to provide an overview of currently existing TMJ implants and to discuss relevant issues, including some of the challenges and current needs facing TMJ research. Additionally, this article describes some of the currently available TMJ surgical procedures, the use of autografts and alloplastic materials (with primary emphasis on TMJ implants) for TMJ reconstruction, and some suggestions for future research. Past incidents of clinical failures of TMJ implants have been attributed to several reasons. The important factors that are responsible for the past failures include lack of a sound scientific approach and inadequate basic research to study the underlying causes for pathologies and their remedies of the TMJ. All these previously mentioned concerns have prompted current biomedical researchers to address many overlooked issues in relation to studying temporomandibular disorders and TMJ implants. Future research should be aimed toward addressing TMJ problems with a multidisciplinary approach, emphasizing simultaneous involvement from clinical (i.e., dentists and physicians) and nonclinical personnel (i.e., oral biologists, bioengineers, biostatisticians, physiotherapists, and pain management specialists).

A preliminary evaluation of the surface of surgically removed Proplast/Teflon interpositional disc implants from human temporomandibular joints

A preliminary evaluation of the surface of surgically removed Proplast/Teflon interpositional disc implants from human temporomandibular joints

Mechanical wear behavior of nanocrystalline and multilayer diamond coatings on temporomandibular joint implants

We used microwave plasma chemical vapor deposition to deposit nanocrystalline and multilayer (nanocrystalline/microcrystalline/nanocrystalline) diamond thin films on Ti-6AI-4V substrates imitating the condyle and fossa components of the temporomandibular joint. We tested the condyle/fossa pairs for wear in a mandibular movement simulator for an equivalent of two years of clinical use. Analysis of the wear surfaces by optical microscopy, scanning electron microscopy (SEM), and Raman spectroscopy showed that damage in both the films was minimal, no loss of film occurred and the wear performance was superior for the multilayer film. Comparisons with an uncoated condyle/fossa pair showed that the coated temporomandibular joint pairs had improved wear performance.

Treatment of temporomandibular joint ankylosis by a modified fossa prosthesis

Background and objective: Treatment of temporomandibular joint ankylosis is a challenge and suffers from a high incidence of recurrence. Although treatment of ankylosis has been tried as early as nearly 200 years ago, no single technique produced satisfactory results. An alternative technique and a modified spacer system are described in this paper. Material and methods: Fifteen patients, nine of whom had unilateral and the remaining six had bilateral ankylosis were evaluated. Modified fossa implants were used in all cases. Results: The highest incidence of ankylosis was observed in the 11–20 year age group (nine patients). Falls during childhood was the common aetiological factor. Eight patients had been previously operated upon. Postoperative interinsicial opening values were remarkably different from the preoperative ones and the long-term results were satisfactory. Conclusion: With continued research and development in the treatment of ankylosis, temporomandibular joint implants will become more predictable and reliable. This specially designed fossa implant seems to be promising in the treatment of TMJ ankylosis.

Properties of nanocrystalline diamond thin films grown by MPCVD for biomedical implant purposes

Nanocrystalline diamond (NCD) thin films have been grown by microwave plasma chemical vapor deposition (MPCVD) and investigated to determine their suitability for biomedical applications. Growth conditions were chosen to produce very uniform films over the surface of curved temporomandibular joint implants. These parameters include methane flow rates exceeding 20% of the hydrogen gas flow rate, and chamber pressure and microwave power were maintained at 30 Torr and 0.73 kW, respectively, in a Wavemat 6 kW MPCVD device. Films (3 μm thick) that completely coated 2.54-cm-diameter Ti–6Al–4V disks under these conditions exhibit mean grain size of 30.4 nm as determined by XRD peak broadening, hardness of 80 GPa as determined by nanoindentation, RMS mean roughness of 15.3±5.3 nm as determined by stylus profilometry, and film adhesion toughness ( Γ C) of 158 J/m 2 as determined by a Rockwell indentation method. Similar deposition performed on small Ti–6Al–4V hemispheres produce films with smaller mean grain size of 21.1 nm and correspondingly lower hardness and roughness. Overall, these films exhibit properties well suited for use in biomedical applications.

Clinical evaluation of patients with temporomandibular joint implants

Purpose: An undetermined number of patients with temporomandibular joint (TMJ) symptoms have been treated with intra-articular disc implants composed of Teflon ethylene/propylene or Teflon polytetrafluoroethylene and aluminum oxide (Proplast-Teflon; Vitek, Houston, TX). These implants have shown the potential to fragment in situ resulting in nonbiodegradable particles that stimulate a giant cell reaction and lead to degeneration of local structures, pain, and limitation of mandibular opening. We examined the possible relationship between TMJ implants and persistent pain, responses to sensory stimuli, quality of life, and systemic immune dysfunction. Patients and Methods: This case series (32 patients) were referred from university-based orofacial pain centers and private practices from across the United States. Laboratory and clinical assessments evaluated orofacial pain symptoms, neurologic function, clinical signs and symptoms of rheumatologic disease, physical function, systemic measures of immune function, and behavioral measures. Results: We found that TMJ implant patients appeared to have altered sensitivity to sensory stimuli, a higher number of tender points with a diagnosis of fibromyalgia, increased self-report of chemical sensitivity, higher psychologic distress and significantly lower functional ability. Systemic illness or autoimmune disease was not evident in this series of TMJ implant patients. Conclusions: Significant problems were noted on clinical assessment of TMJ implant patients. This is a US government work. There are no restrictions on its use. J Oral Maxillofac Surg 60:1389-1399, 2002

Particle-induced Phagocytic Cell Responses are Material Dependent: Foreign Body Giant Cells Vs. Osteoclasts from a Chick Chorioallantoic Membrane Particle-implantation Model

There is increasing concern about particles generated from wear-prone implants that are placed in body tissues, including artificial hip, knee, and jaw joints. Although phagocytes and foreign body giant cells are associated with inhaled or embedded particulate debris, some particles also induce bone digestion by eliciting the differentiation and proliferation of highly specialized osteoclastic cells. This report describes the differential phagocytic cellular responses to four implant-related types of ground, model wear particles in a live-egg cell-response model, as implants to the chick chorioallantoic membrane (CAM): polymethylmethacrylate (PMMA), a main constituent of some temporomandibular joint (TMJ) implants and orthopedic cements used to retain artificial hips and knees; Proplast-HA, an implantable composite of polytetrafluoroethylene (PTFE) and degradable mineral (hydroxyapatite) that has been associated with bone erosion around failed TMJ implants; talc, a nondegradable mineral sometimes found in tissues as a contaminant from talc-coated surgical gloves; and authentic bone, known to induce the formation of osteoclastic cells. Light and electron microscopy of CAM tissues harvested, sectioned and stained with special reagents for the enzymes tartrate-resistant acid phosphatase (TRAP) and tartrate-resistant adenosine triphosphatase (TrATPase), and for the osteoclast-specific antigen 121F, showed that only authentic bone and the degradable HA-rich particles induced osteoclast formation. From these results, and supporting data with polypropylene particles, it is concluded that nonbiodegradable polymer particles, alone, do not induce bone dissolution. Inert polymers do induce foreign body giant cells without the external mineral digestion qualities unique to osteoclasts, however. The chick embryo model system allows quick and affordable examination of material-dependent differences in phagocytic cellular responses to implant wear debris and particles from various occupational environments.