The Contemporary Management of Temporomandibular Joint Intra-Articular Pain and Dysfunction.

The understanding of the causes of temporomandibular joint pain and dysfunction has evolved over 50 years. Historically, the term internal derangement has been used to describe the abnormal relationship between the articular disc, condyle, and glenoid fossa, which was thought to correlate with patient symptoms. It is now known that the pathophysiology of intra-articular pain and dysfunction (IPD) involves synovitis, capsular impingement, symptomatic disc displacement, or a combination of these. Symptomatic disc displacement should only be considered to be a potential source of IPD after synovitis and capsular impingement have been treated. This philosophy provides the opportunity for most patients with IPD to be initially treated nonsurgically or with minimally invasive procedures such as arthrocentesis or arthroscopy.

Does Emotional State Improve Following Temporomandibular Joint Total Joint Replacement?

BACKGROUND: Temporomandibular joint total joint replacement (TMJTJR) offers patients the opportunity for improved function and reduced pain. TMJTJR also has the potential to affect a patient's emotions in a positive or negative manner. PURPOSE: The purpose of this study was to evaluate changes in emotional state for subjects undergoing TMJTJR. STUDY DESIGN, SETTING, SAMPLE: The authors implemented a retrospective cohort study. Subjects who received TMJTJR were identified from the TMJ Inter Network, which is a study group comprising more than 130 temporomandibular joint surgeons. Subjects between the ages of 18 and 65 years with complete medical records and pre/post TMJTJR video/audio recordings were enrolled in the study. PREDICTOR VARIABLE: The predictor variable was time (preoperative and postoperative). MAIN OUTCOME VARIABLES: The primary outcome variable is change in the emotional state. All subjects had preoperative (T0) recorded interview as well as a postoperative (T1) interview at 3 to 6 months. The eight-category emotional state was classified as neutral, happy, sad, angry, fearful, disgusted, surprised, and bored. The three-category emotional state was classified as neutral, positive, and negative. The emotional state was measured using artificial intelligence at T0 and T1. The secondary outcome variable was pain score and maximal interincisal opening. COVARIATES: The covariates are gender, age, diagnosis, prosthetic side, TMJTJR design, and TMJTJR type. ANALYSES: The relationship between emotional state change and covariates was examined using both the χ2 test and the Kruskal-Wallis H test. The significance of the change in categorical data after surgery was examined using the McNemar-Bowker test. P values < .05 were considered statistically significant. RESULTS: Thirty-three subjects were included in the study. The mean age was 30.09 ± 8.69 with 15 males (45%) and 18 females (55%). The percentage of subjects with preoperative neutral, happy, sad, angry, and fearful emotional states was 24, 15, 24, 9, and 27%, respectively. The percentage of subjects with postoperative neutral, happy, sad, angry, and fearful emotional states was 21, 39, 21, 12, and 6%, respectively. The change in emotional state was statistically significant (P = .037). There was no statistically significant relationship between covariates and emotional state changes (P > .05). CONCLUSION: According to the assessment of artificial intelligence, TMJTJR improves the emotional state of patients.

Characteristics of Medical Malpractice Claims Involving Temporomandibular Joint Surgery in the United States.

PURPOSE: Medical malpractice claims contribute to the practice of defensive medicine which exposes patients to unnecessary tests and limits access to care. The purpose of this study is to characterize medical malpractice claims involving temporomandibular joint (TMJ) operations by oral and maxillofacial surgeons in the United States. MATERIALS AND METHODS: Retrospective cross-sectional study of closed medical malpractice claims against oral and maxillofacial surgeons in the Unites States insured by OMS National Insurance Company, RRG (OMSNIC), from January 1, 2016, through December 31, 2020. All claims were obtained from the OMSNIC claims database and classified by procedure type. The primary outcome measure was closed claims involving a TMJ operation. Claims regarding postoperative TMJ complications from non-TMJ operations were excluded. Predictor variables included alleged error and type of TMJ procedure performed. Claim outcome was reported as a secondary outcome measure. Additional outcomes measured included claims involving dentoalveolar or dental implant procedures. Descriptive statistics were performed, and risk ratios were calculated for TMJ claim settlement by alleged error and procedure. Significance was set at P < .05. RESULTS: A total of 1455 closed claims occurred during the study period. There were 14 closed claims involving a TMJ operation (0.96% of all claims). "Improper performance" was the most common alleged error for TMJ claims. Two claims (1 TMJ arthroscopy and 1 TMJ replacement) were settled with payment, and the alleged error for these claims was improper performance. No TMJ claim received a court-adjudicated payout. Dentoalveolar and dental implant-related claims made up 68.73% (n = 1,000) and 15.53% (n = 226) of all OMSNIC claims, respectively. The risk of a settlement was not significantly influenced by alleged error or TMJ procedure performed. CONCLUSIONS: Medical malpractice claims against oral and maxillofacial surgeons for TMJ operations are very uncommon. Medical malpractice risk should not factor into a surgeon's decision to exclude TMJ operations from their practice.

Alloys Used in Different Temporomandibular Joint Reconstruction Replacement Prostheses Exhibit Variable Microstructures and Electrochemical Properties.

PURPOSE: Metallic temporomandibular joint replacement (TMJR) systems vary depending on design, material composition, and manufacturing methods such as casting, forging, and additive manufacturing. Therefore, the purpose of this study was to measure the association between manufacturing process of TMJR systems in terms of microstructure and electrochemical properties. MATERIALS AND METHODS: The sample was composed of new or surgically retrieved TMJ replacement devices of either titanium alloy (Ti6Al4V) or cobalt-chromium-molybdenum (CoCrMo) alloy from 8 different manufacturers. The primary predictor variable was alloy type, according to its manufacturing process (wrought, cast, additively manufactured [AM]). The primary outcome variables were 1) microstructure (grain size, aspect ratio, and phase content) and 2) corrosion potential and current, polarization resistance, and capacitance. Differences between alloy groups were determined by t tests, Kruskal-Wallis, and Mann-Whitney tests. RESULTS: We demonstrated that the TMJR CoCrMo and Ti6Al4V alloy microstructures can vary broadly within American Society for Testing and Materials specifications, where the components made of Ti6Al4V had 3 types of microstructures (equiaxial, bimodal, and martensitic) out of 10 samples, and the components made of CoCrMo had 2 types of microstructure (equiaxial and dendritic) out of 16 samples. Some CoCrMo alloys exhibited preferential corrosion sites, while wrought Ti6Al4V alloys trended toward a superior corrosion behavior (corrosion rate: 2 × 10-9 A/cm2, polarization resistance: 5,000,000 kΩcm2, and capacitance: 10 µSsa/cm2) compared with AM alloys (39 × 10-9 A/cm2, 1676 kΩcm2, 36 µSsa/cm2, respectively), where 4 samples of each group were tested and repeated 5 times. Among four AM devices, two exhibited a significantly inferior corrosion behavior. CONCLUSIONS: Although AM is an exciting emerging new technology that allows manufacturing of custom-made TMJR, their corrosion behavior is still inferior in comparison to that of traditional wrought alloys. Preventing corrosion is crucial because it can cause surface defects that may lead to implant fracture.

Is Heterotopic Ossification Removal From Alloplastic Temporomandibular Joint Prosthesis Using Er,Cr:YSGG Laser Superior to Conventional Methods?

PURPOSE: Heterotopic ossification (HO) formed over the major components and fixation screw heads of an alloplastic temporomandibular joint replacement (TMJR) prosthesis can result in decreased quality of life, limited function, prosthesis failure, and hinder prosthesis revision, replacement, or removal. This study simulated HO removal from the major components and fixation screw heads of alloplastic TMJR prostheses using an erbium, chromium-doped yttrium, scandium, gallium, and garnet (Er,Cr:YSGG) laser and compared the results to conventional methods of HO removal. The surface morphology and chemical structure of the exposed components were analyzed. The investigators hypothesize that HO removal with an Er,Cr:YSGG laser causes less damage to TMJR prosthesis components compared to conventional HO removal methods. METHODS: This multiple test descriptive analysis simulated HO removal from TMJR prostheses mounted to stereolithic models. Simulated HO removal was completed using a novel Er,Cr:YSGG laser method and conventional methods which utilized a fissure carbide bur in a high-speed rotary instrument, a standard osteotome, and an ultrasonic aspirator. Surfaces exposed on the TMJR prostheses were analyzed for morphological or chemical change using scanning electron microscopy, energy dispersive X-ray spectroscopy, and Raman spectroscopy. RESULTS: The Er,Cr:YSGG laser did not adversely affect the titanium screws or titanium components of the TMJR prostheses, while conventional methods of HO removal did. HO removal using the Er,Cr:YSGG laser and conventional methods both inflicted surface damage to the fossa ultrahigh molecular weight polyethylene component of the TMJR prostheses. CONCLUSION: Damage inflicted to titanium alloy or commercially pure titanium components of TMJR prostheses by conventional HO removal methods can be avoided by instead removing HO with an Er,Cr:YSGG laser. However, long exposure of the Er,Cr:YSGG laser to ultrahigh molecular weight polyethylene surfaces should be avoided. Additional research to expand on applications to other procedures and in other surgical fields is encouraged.

How Does a Unilateral Temporomandibular Joint Replacement Affect Bilateral Masseter and Temporalis Muscle Activity?-A Prospective Study.

PURPOSE: Total alloplastic temporomandibular joint replacement (TMJR) requires the detachment of the masseter muscle (MM) at its insertion to the lateral ramus and often the resection of the coronoid process (insertion of the temporalis muscle). There is little literature on how a detachment affects the muscles. The present study evaluates the long-term masticatory muscle activities and maximum voluntary bite force (MVC) in patients with unilateral TMJR. PATIENTS AND METHODS: Surface electromyography of the MM and anterior temporalis muscle during bite force testing and MVC were evaluated bilateral preoperatively (T0), 1 (T3), 2 (T4), 3 (T5), and 4 years (T6) postoperatively. The percentage overlapping coefficient (index of the symmetric distribution of muscular activity) was calculated. Differences between stock or custom devices were evaluated. RESULTS: Fourteen patients were enrolled, 4 males and 10 females, age 47.3 ± 14.3 years at TMJR placement. In 11 patients, the coronoid process was resected, 5 patients received stock, and 9 custom prostheses. After surgery, a trend in the improvement of bilateral surface electromyography activities and MVC was found without statistical significance for the side comparison or the time of the investigation. The percentage overlapping coefficient values showed postoperatively relative (>72%) symmetry in both muscles. Up to T5 on the TMJR side, MM showed higher activity when custom prostheses were used. There was no significant difference between stock and custom prostheses. CONCLUSIONS: The vertical (anterior) fibers of the temporalis muscle are preserved despite the resection of the coronoid process. The anterior temporalis muscle, as a synergist of the MM on the TMJR side, postoperatively partially assumes its abduction function. The detached MM appears to reattach. Generally, the bilateral increase in muscle activity and MVC of both muscles suggests regeneration of the investigated muscles. Custom prostheses seem to have an initial advantage for the reattachment of the MM compared with stock prostheses.

Mechanical Loading Disrupts Focal Adhesion Kinase Activation in Mandibular Fibrochondrocytes During Murine Temporomandibular Joint Osteoarthritis.

PURPOSE: Mechanical overloading is a key initiating condition for temporomandibular joint (TMJ) osteoarthritis (OA). The integrin-focal adhesion kinase (FAK) signaling axis is implicated in the mechanobiological response of cells through phosphorylation at Tyr397 (pFAK) but poorly defined in TMJ health and disease. We hypothesize that mechanical overloading disrupts TMJ homeostasis through dysregulation of FAK signaling. MATERIALS AND METHODS: To assess if FAK and pFAK are viable clinical targets for TMJ OA, peri-articular tissues were collected from patients with TMJ OA receiving a total TMJ replacement. To compare clinical samples with preclinical in vivo studies of TMJ OA, the joints of c57/bl6 mice were surgically destabilized and treated with and without inhibitor of pFAK (iFAK). FAK signaling and TMJ OA progression was evaluated and compared using RT-PCR, western blot, immunohistochemistry, and histomorphometry. To evaluate mechanical overloading in vitro, primary murine mandibular fibrochondrocytes were seeded in a 4% agarose-collagen scaffold and loaded in a compression bioreactor with and without iFAK. RESULTS: FAK/pFAK was mostly absent from the articular cartilage layer in the clinical sample and suppressed on the central condyle and elevated on the lateral and medial condyle in murine TMJ OA. In vitro, compressive loading lowered FAK/pFAK levels and elevated the expression of TGFß, NG2, and MMP-13. iFAK treatment suppressed MMP13 and Col6 and elevated TGFß, NG2, and ACAN in a load independent manner. In vivo, iFAK treatment moderately attenuated OA progression and increased collagen maturation. CONCLUSION: These data illustrate that FAK/pFAK is implicated in the signaled dysfunction of excessive mechanical loading during TMJ OA and that iFAK treatment can moderately attenuate the progression of cartilage degeneration in the mandibular condyle.

Does Maximum Voluntary Clenching Force Pose a Risk to Overloading Alloplastic Temporomandibular Joint Replacement?-A Prospective Cohort Study.

PURPOSE: The amount of maximum voluntary clenching (MVC) force may influence functional loading at the polyethylene/metal bearing surfaces in alloplastic total temporomandibular joint replacement (TMJR). The aim of this study was to measure ipsilateral MVC and estimate the risk for revision due to overloading of the TMJR. METHODS: A prospective cohort study design was used to study patients who underwent alloplastic TMJR. The primary predictor was time after TMJR, the secondary predictors were age at TMJR placement, coronoidectomy, prior ipsilateral TMJ surgeries, TMJR design (custom, stock), and bite location. The primary outcome variable was MVC, the secondary outcome was need for TMJR revision. Data were collected preoperatively (T0), and 1 year (T1), 2 to 3 years (T2) and ≥4 years postoperatively (T3). Analysis of variance (ANOVA) with post hoc Tukey-HSD and regression analysis was used for statistical analysis. P < .05 was considered significant. RESULTS: Thirty-seven patients (58 TMJR) with unilateral (n = 16) and bilateral (n = 21) TMJR were enrolled; 8 males (12 TMJR) and 29 females (46 TMJR). Average age was 46.4 ± 14.9 years. MVC increased significantly over the observation period (P = .000). At all observation time points, age at TMJR placement and bite location significantly influenced MVC (P = .000). Coronoidectomy and prior ipsilateral TMJ surgeries did not demonstrate a significant influence on MVC. TMJR design influenced MVC significantly at T3 (P = .006). Regression analysis identified age as a significant factor for higher MVC. No TMJR required revision or replacement. CONCLUSIONS: Based on this study, ipsilateral MVC increases significantly after TMJR. However, since MVC is significantly lower than in healthy test-patients, a considerably lower functional loading at the polyethylene/metal bearing surfaces can be assumed. Lower loading at the TMJR bearing surfaces and at the cortical screw fixation sites suggest a potential longer lifespan compared to other artificial joints like hip and knee prostheses.

Unilateral, Alloplastic Temporomandibular Joint Reconstruction, Biomechanically What Happens to the Contralateral Temporomandibular Joint?-A Prospective Cohort Study.

PURPOSE: Unilateral alloplastic total temporomandibular joint reconstruction (TMJR) might influence the contralateral side joint function. This study's purpose was to estimate the risk for contralateral TMJR and the jaw function of the contralateral untreated temporomandibular joint (TMJ). PATIENTS AND METHODS: A prospective cohort study design was used for patients who underwent unilateral alloplastic TMJR. The primary predictor was time after TMJR, and the secondary predictors were pre-TMJR mandibular angle resection, prior ipsilateral TMJ surgeries, and TMJR design (custom, stock). The primary outcome variable was the need for contralateral TMJR. The secondary outcome variables were the results of jaw function-jaw tracking, maximum voluntary clenching, surface electromyography, and pressure pain thresholds (PPT) and patient's quality-of-life (oral health-related quality-of-life [OHrQoL]). Data were collected preoperatively (T0), and 1 year (T1), 2-3 years (T2), and ≥ 4 years postoperatively (T4). Analysis of variance with post hoc Tukey -HSD test and multiple linear regression analysis were used for statistical analysis. P < .05 was considered significant. RESULTS: Thirty-nine patients were enrolled, 15 males and 24 females, with an average age of 48.9 ± 16.2 years. Two patients (5.1%) required a contralateral TMJR. Contralateral condylar motion, incisal laterotrusion, and protrusion slightly decreased, while incisal opening (P = .003), rotation angle (P = .013), opening deflection, surface electromyography activity, maximum voluntary clenching (P = .01), PPTs, and OHrQoL all increased. Pre-TMJR mandibular angle resection had an impact on PPTs and subjective outcomes and prior ipsilateral TMJ surgeries on the opening rotation angle. CONCLUSIONS: Based on this study, bilateral TMJR does not appear necessary when the contralateral TMJ is healthy. Unilateral alloplastic TMJR is associated with improved contralateral jaw function and OHrQoL.

An International Survey on Temporomandibular Joint Surgeon's Implementation and Management of Discectomy in Treating Temporomandibular Joint Internal Derangement.

PURPOSE: To survey temporomandibular joint (TMJ) surgeons to determine current practice trends and perceptions regarding the role of discectomy for the treatment of TMJ internal derangements. METHODS: An anonymous 5-part web-based survey was sent to TMJ surgeons. The survey was created and distributed, and the data were collected with the University of Michigan Qualtrics platform. Responses were compared based on operative volume, tendency to replace the disc, and likelihood of requiring temporomandibular joint replacement (TJR) after discectomy. Spearman correlations were used to test statistically significant differences. Domain-level analyses were also performed by summarizing items into 3 domain scores. Analyses were performed in SAS V9.4 (SAS Institute Inc., Cary, NC, USA). RESULTS: Fifty-nine surgeons (33.9%) completed the survey. Discectomy was not considered to be a useful procedure by 85% of respondents, and 74% would not consider discectomy as a first surgical option. Most would consider discectomy (64%) before alloplastic total joint replacement. Discectomy was preferred over discopexy for the management of anterior disc displacement with reduction by high volume surgeons (89%), but most (72%) did not feel that discectomy was beneficial over arthroscopy in the treatment of anterior disc displacement without reduction and concomitant degenerative bony changes. In managing symptomatic disc perforation, 66% agreed that discectomy is the procedure of choice and 49% felt that interpositional tissue is indicated in most cases after discectomy. Respondents who reported fewer re-operations requiring alloplastic TJR after discectomy had, on average, more positive perceptions of discectomy on the benefits domain (P = .03), better than alternatives domain (P = .03), and fewer concerns on the perceived adverse effects domain (P = .03). CONCLUSIONS: TMJ surgeons do not employ TMJ discectomy in most cases of TMJ internal derangement. However, discectomy is considered useful in cases of disc perforation or for persistent symptomatic disc displacement without reduction, in an attempt to avoid alloplastic TJR. Common adverse effects included joint noises and osteoarthrosis, and the use of interpositional disc replacement tissue did not alter the incidence of adverse effects or complications reported.

Temporomandibular Joint Bioengineering Conference: Working Together Toward Improving Clinical Outcomes.

The sixth temporomandibular joint (TMJ) Bioengineering Conference (TMJBC) was held on June 14-15 2018, in Redondo Beach, California, 12 years after the first TMJBC. Speakers gave 30 presentations and came from the United States, Europe, Asia, and Australia. The goal of the conference has remained to foster a continuing forum for bioengineers, scientists, and surgeons and veterinarians to advance technology related to TMJ disorders. These collective multidisciplinary interactions over the past decade have made large strides in moving the field of TMJ research forward. Over the past 12 years, in vivo approaches for tissue engineering have emerged, along with a wide variety of degeneration models, as well as with models occurring in nature. Furthermore, biomechanical tools have become more sensitive and new biologic interventions for disease are being developed. Clinical directives have evolved for specific diagnoses, along with patient-specific biological and immunological responses to TMJ replacement devices alloplastic and/or bioengineered devices. The sixth TMJBC heralded many opportunities for funding agencies to advance the field: (1) initiatives on TMJ that go beyond pain research, (2) more training grants focused on graduate students and fellows, (3) partnership funding with government agencies to translate TMJ solutions, and (4) the recruitment of a critical mass of TMJ experts to participate on grant review panels. The TMJ research community continues to grow and has become a pillar of dental and craniofacial research, and together we share the unified vision to ultimately improve diagnoses and treatment outcomes in patients affected by TMJ disorders.

Are Rib Grafts Still Used for Temporomandibular Joint Reconstruction?

PURPOSE: Patients with end-stage temporomandibular joint (TMJ) pathology require TMJ reconstruction, which can be accomplished with autogenous tissue or alloplastic materials. This survey study evaluates experienced TMJ surgeons' preferences for autogenous costochondral grafts (CCGs) and/or alloplastic prostheses for TMJ reconstruction. MATERIALS AND METHODS: This cross-sectional study used an online public survey domain to query an anonymous cohort of volunteer surgeons from the American and European Societies of Temporomandibular Joint Surgeons about their TMJ reconstruction preferences. The survey questioned these surgeons' current and previous use of CCG for TMJ reconstruction, changes in practice pattern in this regard over the years, indications for CCG, and postoperative CCG outcomes. The responses were subsequently catalogued, means were calculated, descriptive statistics were analyzed, and trends were identified. RESULTS: Of 150 surgeons contacted, 92 responded to the survey. Of the respondents, 84 (91.3%) reported that they had performed total TMJ reconstruction in the past or continue to perform total TMJ reconstruction. However, only the 66 surgeons who completed the survey in its entirety were included in the analysis. Among these surgeons, 95.5% (63 of 66) reported that their current preferred method for TMJ reconstruction was an alloplastic TMJ replacement prosthesis; 86.4% (57 of 66) preferred a custom TMJ prosthesis, whereas 9.1% (6 of 66) preferred a stock TMJ prosthesis. Only 4.5% of the respondents (3 of 66) currently preferred CCG for TMJ reconstruction. CONCLUSIONS: Of the respondents, 95.5% preferred alloplastic TMJ replacement. This preference was reported based on fewer postoperative complications and more predictable outcomes using alloplastic TMJ prostheses. In cases in which CCG revision was indicated, an alloplastic TMJ prosthesis was used, indicating that surgeons should consider an alloplastic TMJ replacement device as the primary option for TMJ reconstruction for the management of most end-stage TMJ diseases.

Does Metal Hypersensitivity Have Relevance in Patients Undergoing TMJ Prosthetic Replacement?

PURPOSE: Although concerns regarding implant-related metal hypersensitivity exist, no guidelines have been accepted for screening or treatment of patients with metal sensitivity before temporomandibular joint replacement (TMJR). The present study aimed to determine the trends in TMJR metal sensitivity screening and the effect of positive test results on patient treatment. MATERIALS AND METHODS: A questionnaire was distributed to members of the American Society of Temporomandibular Joint Surgeons and the European Society of Temporomandibular Joint Surgeons using a web-based data collection and analysis tool. The questions aimed to establish the screening methods used to establish a diagnosis of metal hypersensitivity and any changes in management when metal hypersensitivity had been documented. RESULTS: A total of 72 responses (32.43%) were collected through the survey, with respondents primarily practicing in the United States (47.22%). Of the participants, 75% believed that metal hypersensitivity occurs with TMJR and only 2.77% did not. Most agreed that patients should be questioned about any metal sensitivities before consideration for TMJR (91.66%), and 80.55% routinely asked their patients if they had a previous sensitivity to any metals. Nickel was the most commonly encountered metal allergen (64.28%). If a metal allergy were reported, 44.28% of surgeons would refer the patient to determine the specific metal allergen. The diagnosis for metal allergy was based primarily on patient signs and symptoms (52.85%) and an allergist or dermatologist consultation (44.28%). The lymphocyte transformation test was the test most used by respondents to confirm the diagnosis. Of the surgeons, 41.42% would choose to observe/monitor as their first choice for patients testing positive for metal hypersensitivity. In the case of a "mild" reaction to metal hypersensitivity testing, 54.28% would alter their implant choice to a nonreactive metal component. For "severe" reactions to preoperative metal hypersensitivity testing, 62.85% would alter their implant choice to a nonreactive metal component, and 22.85% would choose not to perform TMJR. CONCLUSIONS: The results from the present study have demonstrated that respondent TMJ surgeons agree that metal hypersensitivity occurs with TMJR. However, their approaches to screening and managing metal hypersensitivity vary. Further research of this topic is required to eventually develop specific management pre- and postoperative guidelines for the treatment of patients with metal sensitivities.

Temporomandibular Joint Prosthesis Revision and/or Replacement Survey and Review of the Literature.

PURPOSE: The purpose of the present study was to report the temporomandibular joint (TMJ) alloplastic reconstruction (TMJR) revision and/or replacement rates and associated complication outcomes data gathered from experienced TMJ surgeons and to review the recent relevant data. MATERIALS AND METHODS: A 21-question anonymous on-line survey was sent to all Commission on Dental Accreditation-approved oral and maxillofacial surgery program directors and to members of the European Society of TMJ Surgeons and the American Society of Temporomandibular Joint Surgeons. RESULTS: Of the surgeons sent the survey, 22% completed the full questionnaire. Most responses were from surgeons who routinely perform TMJR surgery (93.5%). Of the respondents, 28.3% had more than 30 years of experience and 73.9% were full-time academic faculty. A total of 4638 TMJR procedures were recorded and analyzed. The incidence of TMJR revision (keeping the same device) was 3% and that of replacement (placing a new device) was 4.9%. The most common reason for revision was heterotopic ossification (27.5%). The most common reason for replacement was infection (21.1%). Revision was successful in 86.7% and replacement in 94.6% of the patients at the longest follow-up reported. CONCLUSIONS: The data from the present study have shown that the incidence is low and the success rate is high for TMJR revision and replacement.

Custom Alloplastic Temporomandibular Joint Reconstruction: Expanding Reconstructive Horizons.

Custom alloplastic temporomandibular joint (TMJ) reconstruction has been well established for the management of end-stage TMJ disease. However, its use in congenital TMJ deformities is limited. Here, the authors present initial outcomes of skeletally mature patients who underwent custom alloplastic TMJ reconstruction and simultaneous orthognathic surgery.A retrospective case series of patients who underwent custom alloplastic TMJ reconstruction concurrent with orthognathic surgery between 2014 and 2019 was completed. Functional, aesthetic and orthodontic outcomes as well as complications were recorded.Seven TMJs in 5 skeletally mature patients (4 female, 1 male, ages 16-30) (2 bilateral, 3 unilateral) were replaced. All but 1 patient had previous attempts at reconstructive surgery with poor results. All cases were prepared using virtual surgical planning and underwent concomitant maxillomandibular orthognathic surgery. All patients demonstrated improved post-operative occlusions. Four of 5 patients achieved >30 millimeters of post-operative MIO. Complications included ear canal perforation and facial nerve dysfunction.There were no infections or other implant-related complications. Mean follow up was 2 years and 15 days. Alloplastic TMJ reconstruction at the time of skeletal maturity for patients with congenital mandibular TMJ defects is an alternative to existing management options. Further long-term prospective outcomes studies are ongoing.

Material Hypersensitivity and Alloplastic Temporomandibular Joint Replacement.

PURPOSE: There appears to be little consensus on how to evaluate and manage patients reporting a possible allergic reaction to joint replacement devices containing metal. This article presents an analysis of the current orthopedic literature in this regard as it relates to diagnosis, testing, and management. Based on that evidence, a management algorithm for metal hypersensitivity in the patient receiving an alloplastic temporomandibular joint replacement is proposed. MATERIALS AND METHODS: Orthopedic surgery has recognized metal sensitivity as a problem in joint replacement; using a PubMed search for this topic, the pertinent orthopedic literature was reviewed. RESULTS: Metal hypersensitivity response to implant materials is often a diagnosis of exclusion. The 2 most commonly used tests are the in vivo skin patch test and in vitro lymphocyte transformation test. Initially, conservative management is indicated and other more common causes of symptomatic total joint replacement should be fully explored. Device removal should be considered a last resort. CONCLUSIONS: Before a primary total joint replacement, testing could be helpful when a patient reports a history of intolerance to jewelry or of an allergic reaction to a prior metal implant. However, to date, routine testing is not supported by the literature.

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.

Idiopathic Condylar Resorption: A Survey and Review of the Literature.

PURPOSE: Idiopathic condylar resorption (ICR) is a relatively uncommon condition. Its diagnosis, etiology, and management options are controversial. Furthermore, it is difficult for 1 provider to collect a large cohort of ICR patients to develop a statistically significant study of these concerns. Therefore, the purpose of this study was to survey experienced temporomandibular joint (TMJ) surgeons who have managed ICR cases relative to these concerns, as well as review the management outcome literature. MATERIALS AND METHODS: SurveyMonkey (Palo Alto, CA) was used to canvas the 88 international TMJ surgeons on the TMJ Concepts (Ventura, CA) InterNetwork. This network connects a group of surgeons across the world who consistently perform TMJ surgery. The intent was to provide a global snapshot of the demographic, epidemiologic, diagnostic workup, and outcome data related to the management of ICR cases. RESULTS: The surveys from surgeons who did not respond to all 12 questions were not included in the results. After application of the exclusion criteria, complete data on a cohort of 100 patients were obtained and used for the study. A history of hormonal imbalance was reported in only 10% of patients; however, 42 of 94 women were reportedly taking birth control pills presumably affecting their menstrual cycles. The most common reason for consultation was Class II malocclusion (98% of patients). Treatment modalities varied and included orthodontics, orthotics, TMJ total joint replacement, orthognathic surgery, and disc repositioning. CONCLUSIONS: ICR management proved to be controversial among the surveyed surgeons. Multiple treatment options have been described in the literature, including medical management, orthognathic surgery only, TMJ and orthognathic surgery, and total joint prosthesis reconstruction. Long-term, controlled, multicenter clinical studies should be developed to evaluate outcomes of all nonsurgical and surgical management options for the ICR patient.

Serum Metal Levels in Maxillofacial Reconstructive Surgery Patients: A Pilot Study.

PURPOSE: The aim of this pilot study was to assay metal concentrations in the serum of patients who had undergone dental implant placement, orthognathic surgery using rigid metal fixation plates and screws, and total temporomandibular joint replacement (TMJ TJR). MATERIALS AND METHODS: Thirty patients were identified and included in this pilot study. Sixteen patients (9 men and 8 women), with an average age of 44 years (range, 19 to 79 yr), provided informed consent to participate and were divided into 3 study groups with 4 patients in each (group 1, orthognathic surgery; group 2, TMJ TJR; and group 3, dental implant placement). A control group consisted of volunteers without any implanted metallic devices. Blood samples for serum metal analysis were obtained and analyzed in accordance with the standardized collection and testing protocols used at the Trace Metal Analysis Laboratory of the Department of Orthopedic Surgery at the Rush University Medical Center (Chicago, IL). RESULTS: All control participants had levels below the normal reference range for all serum markers assessed. In the orthognathic group, 1 patient had an increased serum cobalt level. In the TMJ TJR group, 1 patient had an increased serum cobalt level and another patient had an increased serum chromium level. In the dental implant group, 1 patient had an increased serum titanium level and another had increased serum levels of titanium and chromium. CONCLUSIONS: This is the first study to report on the release of metal into the bloodstream in patients with different maxillofacial implanted metallic objects. The results raise questions regarding the types and magnitude of metal released from maxillofacial reconstruction devices and their potential long-term local and systemic effects. Future large-scale prospective studies involving serial measurements in homogeneous groups of patients could further elucidate the impact of these findings.