Louis G. Mercuri

Twenty-Year Follow-up Study on a Patient-Fitted Temporomandibular Joint Prosthesis: The Techmedica/TMJ Concepts Device

PURPOSEnTo evaluate subjective and objective outcomes of patients receiving Techmedica (currently TMJ Concepts) patient-fitted temporomandibular joint (TMJ) total joint replacement (TJR) devices after 19 to 24 years of service.nnnPATIENTS AND METHODSnThis prospective cohort study evaluated 111 patients operated on by 2 surgeons using Techmedica (Camarillo, CA) patient-fitted TMJ TJR devices from November 1989 to July 1993. Patients were evaluated before surgery and at least 19 years after surgery. Subjective evaluations used standard forms and questions with a Likert scale for 1) TMJ pain (0, no pain; 10, worst pain imaginable), 2) jaw function (0, normal function; 10, no movement), 3) diet (0, no restriction; 10, liquid only), and 4) quality of life (QoL; improved, the same, or worse). Objective assessment measured maximum incisal opening (MIO). Comparison analysis of presurgical and longest follow-up data used nonparametric Mann-Whitney and Wilcoxon signed rank tests. Spearman correlations evaluated the number of prior surgeries in relation to objective and subjective variables.nnnRESULTSnOf the 111 patients, 56 (50.5%) could be contacted and had adequate records for inclusion in the study. Median follow-up was 21 years (interquartile range [IQR], 20 to 22 yr). Mean age at surgery was 38.6 years (standard deviation, 10 yr). Median number of previous TMJ surgeries was 3 (IQR, 4). Presurgical and longest follow-up data comparison showed statistically significant improvement (P < .001) for MIO, TMJ pain, jaw function, and diet. At longest follow-up, 48 patients reported improved QoL, 6 patients reported the same QoL, and 2 patients reported worse QoL. Spearman correlations showed that an increased number of previous surgeries resulted in lower levels of improvement for TMJ pain and MIO.nnnCONCLUSIONSnAt a median of 21 years after surgery, the Techmedica/TMJ Concepts TJR continued to function well. More previous TMJ surgeries indicated a lesser degree of improvement. No devices were removed owing to material wear.

An electrochemical investigation of TMJ implant metal alloys in an artificial joint fluid environment: The influence of pH variation

OBJECTIVEnTo investigate the corrosion behaviour of commonly used TMJ implants alloys (CoCrMo and Ti6Al4V) under simulated physiological conditions.nnnMETHODSnCorrosion behaviour was evaluated using standard electrochemical corrosion techniques and galvanic corrosion techniques as per ASTM standards. Standard electrochemical tests (E(corr), I(corr), R(p) and C(f)) were conducted in bovine calf serum (BCS), as a function of alloys type and different pHs. Galvanic corrosion tests were conducted in BCS at a pH of 7.6. Alloy surfaces were characterized using white-light interferometry (WLI) and scanning electron microscopy (SEM).nnnRESULTSnThe potentiodynamic test results exhibited the enhanced passive layer growth and a better corrosion resistance of Ti6Al4V compared to CoCrMo. Electrochemical impedance spectroscopy measurements demonstrated the influence of protein as a function of pH on corrosion mechanisms/kinetics. Galvanic coupling was not a major contributor to corrosion. SEM and WLI images demonstrated a significantly higher in surface roughness in CoCrMo after corrosion.nnnCONCLUSIONSnThe results of this study suggest that Ti6Al4V shows superior corrosion behaviour to CoCrMo due to its strong passive layer, simulated joint fluid components can affect the electrochemical nature of the metal/electrolyte interface as a function of pH, and the galvanic effect of coupling CoCrMo and Ti6Al4V in a single joint is weak.

Tribocorrosion and oral and maxillofacial surgical devices.

The release of metal ions or material particles, or both, into tissues that surround implanted medical or dental devices can create postimplantation complications. These rare but disturbing events are mainly caused by the mechanical movements of the components of the implant against each other, coupled with the influences of local biochemical and electrochemical factors. Mechanical movement of the components of implants against each other results in friction and wear, the study of which is called tribology. The tribology of an implanted device depends on the patients activity and is affected by variables such as load, frequency, and the surface properties of the components of the implant that are in contact. Local biochemical and electrochemical factors include the ambient pH, and concentrations of protein and oxygen. The effect on local tissues and extracellular fluid can produce biochemical or electrochemical responses to the implant material in the surrounding solution, which is termed corrosion. The combined effect of these mechanical, biochemical, and electrochemical factors is known as tribocorrosion. In this paper we will provide a brief overview of the basic principles of tribocorrosion, and its current status and future perspectives, to create awareness and interest, and to inspire research into its effects on implantable devices in oral and maxillofacial surgery. The information garnered from such investigations, appropriately applied, will not only improve present devices but also will lead to the development of superior ones, ultimately improving care and outcomes for patients.

Management of temporomandibular joint ankylosis.

Temporomandibular joint (TMJ) ankylosis is a pathologic condition where the mandible is fused to the fossa by bony or fibrotic tissues. This interferes with mastication, speech, oral hygiene, and normal life activities, and can be potentially life threatening when struggling to acquire an airway in an emergency. Trauma is the most common cause of TMJ ankylosis, followed by infection. Diagnosis of TMJ ankylosis is usually made by clinical examination and imaging studies. The management goal in TMJ ankylosis is to increase the patients mandibular function, correct associated facial deformity, decrease pain, and prevent reankylosis.

How Many Temporomandibular Joint Total Joint Alloplastic Implants Will Be Placed in the United States in 2030

PURPOSEnThe purpose of this study is to provide a statistical projection of the number of alloplastic temporomandibular joint (TMJ) total joint replacements (TJRs) that will be performed in the United States through the yearxa02030.nnnMATERIALS AND METHODSnThe program directors of all 101 Commission on Dental Accreditation-accredited oral and maxillofacial surgery training programs in the United States were surveyed online by use of a questionnaire developed using Redcap (Chicago, IL) over a 6-week period (February 2015-March 2015). The questionnaire included 19 questions related to each programs TMJ disorder and TMJ TJR curricula, as well as clinical experience. In addition, members of the American Society of Temporomandibular Joint Surgeons were surveyed online using Redcap and via direct survey forms. Moreover, requests for the total number of TMJ TJR devices produced and implanted during the same period were made to the 3 manufacturers of Food and Drug Administration-approved TMJ TJR devices in the United States.nnnRESULTSnThe response rate among program directors was 52.5%, and the total number of TMJ TJR devices implanted in oral and maxillofacial surgery programs in 2005 was 412. This total increased by 38% to 572 in 2014. Statistically, this projects an increase of 58% over the next 16xa0years to 902 TMJ TJR operations by 2030 (95% prediction limits, 768 and 1,037). The total number of TMJ TJR devices distributed by one manufacturer increased from 430 in the year 2000 to 1,004 in 2014 (133%). By use of these data, statistically over the next 16xa0years, the number of TMJ TJR devices distributed by this company is projected to be 1,658 (95% prediction limits, 1,380 and 1,935).nnnCONCLUSIONSnThe data presented in this study show an increasing demand for the use of TMJ TJR devices in the management of end-stage TMJ disorders to the yearxa02030.

Examination of failed retrieved temporomandibular joint (TMJ) implants.

UNLABELLEDnIn the management of end-stage temporomandibular joint disorders (TMD), surgeons must often resort to alloplastic temporomandibular joint (TMJ) total joint replacement (TJR) to increase mandibular function and form, as well as reduce pain. Understanding wear and failure mechanisms of TMJ TJR implants is important to their in vivo longevity. However, compared to orthopedic TJR devices, functional wear of failed TMJ TJR implants has not been examined. Not only do wear and corrosion influence TJR implant in vivo longevity, but so does reactivity of peri-implant tissue to these two events. The aim of this study was to examine and report on the wear of retrieved, failed metal-on-metal (MoM), metal-on-polymer (MoP), and titanium-nitride coated (TiN Coated) TMJ TJR implant components. A total cohort of 31 TMJ TJR devices were studied of which 28 were failed, retrieved TMJ TJRs, 3 were never implanted devices that served as controls. The mean time from implantation to removal was 7.24 years (range 3-15), SD 3.01. Optical microscopy, White Light Interferometry (WLI), Scanning Electron Microscopy (SEM), and Raman spectroscopy were utilized to characterize the surfaces of the devices. Data was acquired and evaluated by analyzing alloy microstructure. Substantial surface damage was observed between the articulating areas of the condylar head and the glenoid fossa components. Damage included pitting corrosion, evidence of deposited corrosion products, specific wear patterns, hard phases, surface depressions, and bi-directional scratches. Electrochemical analysis was performed on the MoM Control, retrieved, failed MoM, and TiN Coated devices. Electrochemical tests consisted of open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) tests conducted using the condylar head of the retrieved failed devices. EIS confirmed material properties as well as corrosion kinetics in vivo help to mitigate corrosion as reflected by the Raman spectroscopy results. In summary, this study demonstrated the role of wear and corrosion interactions on the early failure of TMJ TJR devices. Since the materials employed in most orthopedic TJR devices are similar to those used in TMJ TJR implants, studies such as this can provide data that will improve future embodiment paradigms for both. Further studies will include in vitro investigation of corrosion kinetics and the underlying tribocorrosion mechanism of TMJ TJR devices.nnnSTATEMENT OF SIGNIFICANCEnAn attempt is made in this study, to examine the retrieved TMJ implants and conduct surface and electrochemical analysis; further a translation research approach is employed to compare the observations from the total hip replacement (THR) retrievals. A total cohort of 31 TMJ TJR devices were studied of which 28 were failed, retrieved TMJ TJRs, 3 were never implanted devices that served as controls. Data was acquired and evaluated by analyzing alloy microstructure. Substantial surface damage was observed between the articulating areas of the condylar head and the glenoid fossa components. Electrochemical analysis was performed on the MoM Control, retrieved, failed MoM, and TiN Coated devices. This study demonstrated the role of wear and corrosion interactions on the early failure of TMJ TJR devices. Since the materials employed in most orthopedic TJR devices are similar to those used in TMJ TJR implants, a comparison study was conducted.

Are Oral and Maxillofacial Surgery Residents Trained Adequately in Alloplastic Total Temporomandibular Joint Replacement

PURPOSEnTo assess the current level of experience and training that oral and maxillofacial surgery (OMS) residents receive in alloplastic temporomandibular joint (TMJ) total joint replacement (TJR) at OMS training programs in the United States.nnnMATERIALS AND METHODSnA questionnaire was developed using REDCap (Chicago, IL), and an on-line link was emailed to the program directors of all 101 OMS training programs in the United States accredited by the Commission on Dental Accreditation. The questionnaire included 20 questions related to the programs alloplastic TMJ TJR curriculum and clinical experience. In addition, a Likert scale was used to assess the respondents opinions on resident training and the future of alloplastic TMJ TJR education and its clinical effect and usage.nnnRESULTSnThe study sample included 53 respondents (52.5%). Of the 53 responding OMS programs, 94% provide TMJ TJR didactic lectures presented by OMS faculty. The alloplastic TMJ TJR procedures averaged 0 to 6 annually per program; however, 25% of the programs reported more than 10 cases annually. Infection and continued pain were reported as the most common reasons for alloplastic TMJ TJR device replacement.nnnCONCLUSIONSnIt appears that adequate didactic and clinical training is being provided to OMS residents in alloplastic TMJ TJR during their training. Additional studies might elucidate the actual geographic distribution of OMS surgeons who perform alloplastic TMJ TJR procedures.

Potential Indications for Tissue Engineering in Temporomandibular Joint Surgery

PURPOSEnMusculoskeletal tissue engineering has advanced to the stage where it has the capability to engineer temporomandibular joint (TMJ) anatomic components. Unfortunately, there is a paucity of literature identifying specific indications for the use of TMJ tissue engineering solutions. The objective of this study was to establish an initial set of indications and contraindications for the use of engineered tissues for replacement of TMJ anatomic components.nnnFINDINGSnThere was consensus among the authors that the management of patients requiring TMJ reconstruction as the result of 1) irreparable condylar trauma, 2) developmental or acquired TMJ pathology in skeletally immature patients, 3) hyperplasia, and 4) documented metal hypersensitivities could be indications for bioengineered condyle and ramus TMJ components. There was consensus that Wilkes stage III internal derangement might be an indication for use of a bioengineered TMJ disc or possibly even a disc-like bioengineered fossa liner. However, there was some controversy as to whether TMJ arthritic disease (e.g., osteoarthritis) and reconstruction after failed alloplastic devices should be indications. Further research is required to determine whether tissue-engineered TMJ components could be a viable option for such cases. Contraindications for the use of bioengineered TMJ components could include patients with TMJ disorders and multiple failed surgeries, parafunctional oral habits, persistent TMJ infection, TMJ rheumatoid arthritis, and ankylosis unless the underlying pathology can be resolved.nnnCONCLUSIONSnBiomedical engineers must appreciate the specific indications that might warrant TMJ bioengineered structures, so that they avoid developing technologies in search of problems that might not exist for patients and clinicians. Instead, they should focus on identifying and understanding the problems that need resolution and then tailor technologies to address those specific situations. The aforementioned indications and contraindications are designed to serve as a guide to the next generation of tissue engineers in their strategic development of technologies to address specific clinical issues.

Temporomandibular Joint Disorder Management in Oral and Maxillofacial Surgery

PURPOSEnThis article discusses why the management of temporomandibular joint disorder (TMD) cases leads to some oral and maxillofacial surgeons to actively avoid attracting such patients to their practices, offers some evidence-based explanations, and provides recommendations for resolution that will benefit not only the specialty, but more importantly the patients it serves.nnnMATERIALS AND METHODSnA review of the reasons some surgeons state they do not wish to manage TMD cases is presented, followed by an updated review of the TMD and orthopedic literature discussing not only the importance of a proper diagnosis but also the impact of comorbid conditions, genetics, clinical experience, and patient expectations important to achieving good TMD management outcomes.nnnRESULTSnThe literature shows that the frustration clinicians and TMD and orthopedic patients have had in the past are related to initial misdiagnosis leading to multiple failed procedures, failed materials and devices, failure to understand the impact of comorbid conditions and genetic features on outcomes, clinicians experience in complex cases, and unrealistic outcomes expectations by the clinician and the patient.nnnCONCLUSIONnAlthough it is not reasonable to believe that every graduate of an oral and maxillofacial surgery residency will have an interest in management of TMD cases in their future practices, those who will must understand the importance of the issues of proper diagnosis, the relation of TMD patient comorbidities and prior management to final outcomes, honest awareness of their experience and ancillary support to manage complex cases, and how essential a realistic prognosis is to a successful outcome for the clinician and the patient.

Systemic and local toxicity of metal debris released from hip prostheses: A review of experimental approaches

Despite the technological improvements in orthopedic joint replacement implants, wear and corrosion products associated with the metal components of these implants may result in adverse local tissue and perhaps systemic reactions and toxicities. The current review encompasses a literature review of the local and systemic toxicity studies concerning the effect of CoCrMo wear debris released from wear and corrosion of orthopedic implants and prostheses. Release of metallic debris is mainly in the form of micro- and nano-particles, ions of different valences, and oxides composed of Co and Cr. Though these substances alter human biology, their direct effects of these substances on specific tissue types remain poorly understood. This may partially be the consequence of the multivariate research methodologies employed, leading to inconsistent reports. This review proposes the importance of developing new and more appropriate in-vitro methodologies to study the cellular responses and toxicity mediated by joint replacement wear debris in-vivo.