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

Persistent pain after total temporomandibular joint replacement surgery: clinical characteristics, comorbidities, and risk factors

Chronic post-surgical pain (CPSP) after temporomandibular joint (TMJ) surgery is an under-recognized problem. The aim of this study was to document the characteristics of CPSP and identify patient risk factors and comorbidities associated with the development of CPSP after total TMJ replacement (TJR). This was a retrospective cohort study of patients who underwent TJR between 2000 and 2018 at Massachusetts General Hospital, Boston, USA. The primary outcome was the presence of CPSP and use of pain medications after TJR. The secondary outcome was the risk factors associated with the development of CPSP. A total 88 patients were included (79 females, 9 males). The mean follow-up was 4.2 years. Overall, 68 (77.3%) had CPSP and 20 (22.7%) had no CPSP. Of those with CPSP, 32.4% had severe pain and 45.6% continued to take pain medications. Of the 27 patients with data available on the characteristics of the pain, the majority had myofascial pain, while some developed neuropathic pain. A significant difference was noted between the CPSP and non-CPSP groups in terms of preoperative pain, smoking behavior, and use of opioids, non-steroidal anti-inflammatory drugs, muscle relaxants, and neuropathic pain medications.

Alloplastic temporomandibular joint replacement - past, present, and future: "Learn from the past, prepare for the future, live in the present." Thomas S. Monson

Based on evidence from the orthopaedic, biomedical engineering, and oral and maxillofacial surgical literature, this paper discusses reported successes and failures of past alloplastic temporomandibular joint (TMJ) devices that have led to the development of present total temporomandibular joint replacement (TMJR) devices. The paper concludes with discussion of the ongoing research that will lead to future embodiment (materials, designs, and manufacture) advances in TMJR management of severe and debilitating end-stage TMJ disease, further improving patients' mandibular function, form, and overall quality of life.

Customised Implant for Temporomandibular Joint: New Technique to Design and Stress Analysis to Balance the Loading at Both Ends

The temporomandibular joint (TMJ) is a critical joint for the opening and closing of the mouth. The generation of customised TMJs according to individuals' dental anatomy is needed. Currently, the implants available on the market lack consideration of the patient's dental anatomy. This leads to the creation of an imbalance in the reaction forces on both ends of the TMJ. This requires a slight structural change in the design parameters to give a solution. The purpose of this study is to propose a new design that includes the geometry and materials for a TMJ implant. Stress analysis was carried out on the TMJ to balance the reaction forces at both TMJ ends. A static analysis was performed using ANSYS Workbench, to compare the results of two customised designs of TMJ implants, in order to better balance the reaction forces at both ends. The model in the study showed that the reaction forces for both the patient-specific TMJ implants were nearly balanced. The reaction forces were better balanced, and almost equivalent to the intact conditions. The stresses in the mandible were more uniformly distributed in the customised design of the TMJ implant. The two types of design showed that the custom design took up less space in the patient's region of surgery, making it a better option compared to a stock TMJ implant. The custom implant would allow faster patient rehabilitation, as the reaction forces would be close to those in intact conditions.

Longitudinal surveillance of serum titanium ion levels in patients with indigenous 3D printed total temporomandibular joint replacement

The purpose of this longitudinal study was to surveil the serum titanium ion levels at various time intervals in patients with indigenous 3D-printed total temporomandibular joint replacement (TMJ TJR). The study was conducted on 11 patients (male: 8; female: 3) who had undergone unilateral or bilateral TMJ TJR. Blood samples were drawn preoperatively (T0), 3 months (T1), 6 months (T2), and 1 year (T3) postoperatively. Data were analyzed and a p value of < 0.05 was considered statistically significant. The mean serum titanium ion levels at T0, T1, T2, and T3 was 9.34 ± 8.70 µg/L (mcg/L), 35.97 ± 20.27 mcg/L, 31.68 ± 17.03 mcg/L, and 47.91 ± 15.47 mcg/L respectively. The mean serum titanium ion levels increased significantly at T1 (p = 0.009), T2 (p = 0.032), and T3 (p = 0.00) interval. There was no significant difference between unilateral and bilateral groups. Serum titanium ion continued to show increased levels till the last follow-up of 1 year. These initial serum titanium ion levels increase is due to the initial wear phase of the prosthesis which manifests over 1 year. Further studies with large sample sizes and long-term follow-ups are required to see the deleterious effect if any on the TMJ TJR.

Concomitant Microvascular Aided Extended Temporo-Mandibular Joint Replacement (ME-TJR) and Stock Temporo-Mandibular Joint Replacement (MS-TJR) During Mandibular Reconstruction

Background

Disarticulation is indicated when pathologic process involves the condyle or when a body/ramus lesion extends into condylar process. The goal of reconstruction is to reinstate joint mechanism for function and also to restore facial symmetry.

Aim

Retrospective evaluation of functional and aesthetic outcomes in patients with disarticulation defects of mandible treated with concomitant alloplastic temporomandibular joint replacement and microvascular free flap reconstruction.

Materials and Methods

Nine patients (8 benign pathologies and 1 secondary reconstruction for malignant neoplasm), who underwent mandibular resection with condylar disarticulation and reconstruction with Free microvascular flap and Alloplastic total joint replacement between 2015 and 2022 were included in the study. A modified functional intra-oral Glasgow scale (FIGS)2 was used for quality of life (QOL) scoring. Speech, mastication, swallowing, VAS pain score, mouth-opening, occlusion, facial symmetry and overall patient satisfaction were assessed.

Results

8 patients with benign pathology reported excellent outcome with a QOL score of 13-15 in terms of speech, chewing and swallowing. Pre-operative occlusion of native mandible was maintained in all dentulous patients. VAS score of 0-1 was reported. Mouth opening was adequate in all patients. 2 patients reported mild ipsilateral deviation of mandible. Mild facial asymmetry was reported by 2 patients with an overall satisfaction of 8-9. There were no significant intra/post-operative complications in patients with benign pathology. Failure of stock joint was observed in secondary reconstruction for malignant neoplasm.

Conclusion

Microvascular free flap aided stock or custom alloplastic replacement of temporomandibular joint (MS-TJR, ME-TJR) restores function and aesthetics following mandibular resection with disarticulation of condyle.

Management of Intraoperative Contamination of the Custom Total Temporomandibular Joint Prosthesis

Management of intraoperative contamination of a custom total temporomandibular joint prosthesis has not been reported in the literature. As this complication is rare, it can be unsettling for the surgeon. Improper management may lead to a complicated treatment course and financial consequences. Prevention is the primary strategy for avoidance and appropriate management is dependent on many variables. The purpose of this report is to identify a unique complication associated with placement of a custom temporomandibular joint prosthesis and offer an algorithm for management.

Functioning of the Masticatory System in Patients with an Alloplastic Total Temporomandibular Joint Prostheses Compared with Healthy Individuals: A Pilot Study

BACKGROUND

Most patients with temporomandibular joint (TMJ) issues are successfully treated with nonsurgical methods. However, when end-stage TMJ pathologies occur, invasive management can be required, such as a total TMJ replacement. This cross-sectional pilot study aimed to provide insight into the functioning of the masticatory system, pain, and patient satisfaction in patients treated with a total joint replacement (TJR).

METHODS

A cross-sectional pilot study was conducted to determine the postoperative clinical results of an alloplastic TJR TMJ. Masticatory performance and also insight into maximum voluntary bite force (MVBF), active and passive maximum mouth opening (aMMO/pMMO), pain, and patient satisfaction were measured. Masticatory performance, MVBF, and aMMO of patients with a TJR TMJ were compared with healthy individuals.

RESULTS

Masticatory performance is equal between patients with a TJR TMJ and healthy individuals, but both MVBF and aMMO were significantly smaller in patients with a TJR TMJ. However, patients had almost no pain and were very satisfied with the TJR TMJ treatment.

CONCLUSION

This study revealed that most patients with an alloplastic TJR TMJ were able to function without pain, showed good masticatory performance, and were highly satisfied with their alloplastic TJR TMJ. However, MVBF and aMMO were lower than in healthy individuals.

Vascularized Fibula TMJ Reconstruction: A Report of Five Cases featuring Computerized Patient-specific Surgical Planning

BACKGROUND

Mandibular defects involving the condyle represent a complex reconstructive challenge for restoring proper function of the temporomandibular joint because it requires precise bone graft alignment, or alloplastic materials, for complete restoration of joint function. The use of computerized patient-specific surgical planning (CPSSP) technology can aid in the anatomic reconstruction of mandibular condyle defects with a vascularized free fibula flap without the need for additional adjuncts. The purpose of this study was to analyze clinical and functional outcomes after reconstruction of mandibular condyle defects using only a free fibula graft with the assistance of virtual surgery techniques.

METHODS

A retrospective review was performed to identify all patients who underwent mandibular reconstruction utilizing CPSSP with only a free fibula flap without any temporomandibular joint adjuncts after a hemimandibulectomy with total condylectomy.

RESULTS

From 2018 to 2021, five patients underwent reconstruction of mandibular defects involving the condyle with CPSSP technology and preservation of the native temporomandibular articulating disk. The average age was 62 years (range, 44-73 years). The average follow-up period was 29.2 months (range, 9-46 months). Flap survival was 100% (N = 5). The maximal interincisal opening range for all patients was 22-45 mm with no lateral deviation or subjective joint pain. No patients experienced progressive joint hypomobility or condylar migration.

CONCLUSION

The use of CPSSP technology can aid in the anatomic reconstruction of mandibular condyle defects with a vascularized free fibula flap through precise planning and intraoperative manipulation with optimal functional outcomes.

Alloplastic temporomandibular joint replacement: present status and future perspectives of the elements of embodiment

Medical device embodiment involves the following elements: materials, design, and manufacturing. Failure of any one of these elements can result in failure of the device, despite the others being satisfactory. The abundance of clinical and basic science literature published since 1986, demonstrates the safety and efficacy of alloplastic temporomandibular joint replacement (TMJR). Currently, there are 19 countries producing 41 TMJR devices. More than 75% are custom designed, and 27% are additively manufactured. In light of the increasing number of TMJR devices being designed and manufactured around the world, this paper will discuss TMJR embodiment so that clinicians understand their present status as well as the prospects for the future of new and/or improved TMJR devices, to ensure that these devices continue to be safe and effective long-term surgical options for the management of end-stage TMJ pathologies.

Surface wear in a custom manufactured temporomandibular joint prosthesis

The wear of a novel temporomandibular joint (TMJ) prosthesis was evaluated in an animal model. The prosthesis consisted of an additively manufactured titanium alloy (Ti₆Al₄V) mandibular condyle and glenoid fossa created through selective laser melting, with a machined vitamin E‐enriched ultra‐high molecular weight polyethylene (UHMWPE) surface attached to the fossa. Thirteen TMJ prosthesis were implanted in sheep, six of which had condylar heads coated with HadSat® diamond‐like carbon (H‐DLC). Euthanasia took place after 288 days, equaling 22 years of human mastication. Linear and volumetric wear analysis of the fossa was performed by optical scanning. The condylar head surfaces were assessed by scanning electron and confocal laser microscopy. The average linear UHMWPE wear, when combined with the coated condyle, was 0.67 ± 0.28 mm (range: 0.34–1.15 mm), not significantly differing (p = .3765, t‐test) from the non‐coated combination average (0.88 ± 0.41 mm; range: 0.28–1.48 mm). The respective mean volumetric wear volumes were 25.29 ± 11.43 mm³ and 45.85 ± 22.01 mm³, not significantly differing (p = .1448, t‐test). Analysis of the coated condylar surface produced a mean Ra of 0.12 ± 0.04 μm and Sa of 0.69 ± 0.07 μm. The non‐coated condylar surface measured a mean Ra of 0.28 ± 0.17 μm and Sa of 2.40 ± 2.08 μm. Both Sa (p = .0083, Mann–Whitney U test) and Ra (p = .0182, Mann–Whitney U test), differed significantly. The prosthesis exhibits acceptable wear resistance and addition of the H‐DLC‐coating significantly improved long‐term condylar surface smoothness.

Total Alloplastic Temporomandibular Joint Replacement

Purpose

End-stage temporomandibular joint (TMJ) disease are not uncommon and affects quality of life. Multiple surgical procedures have been mentioned in literature for management of TMJ disease which ranges from conservative management to aggressive resection of involved joint and replacement with alloplastic total joint prosthesis. The purpose of the present paper was to provide an overview of the role of alloplastic total joint prosthesis in TMJ replacement.

Methods and results

Alloplastic total joint prosthesis is nowadays considered as a standard of care in the adult patients who require TMJ replacement. The requirement of alloplastic total prosthesis has increased in present era with the improvement in design and material of implants, surgical skills and reported victorious outcome along with improved quality of life after its use. It provides restoration of form and functions, improvement in quality of life, reduction in pain and maintenance of ramal height. Additionally, in TMJ ankylosis it reduces chances of re-ankylosis and allows facial asymmetry correction. Currently, enough evidence is however not available for replacement in skeletally immature patient.

Conclusion

The authors conclude that the total joint replacement is a standard procedure for end-stage TMJ disease. Every maxillofacial surgeon should be well-acquainted with TMJ replacement.

Automated cortical thickness measurement of the mandibular condyle head on CBCT images using a deep learning method

This study proposes a deep learning model for cortical bone segmentation in the mandibular condyle head using cone-beam computed tomography (CBCT) and an automated method for measuring cortical thickness with a color display based on the segmentation results. In total, 12,800 CBCT images from 25 normal subjects, manually labeled by an oral radiologist, served as the gold-standard. The segmentation model combined a modified U-Net and a convolutional neural network for target region classification. Model performance was evaluated using intersection over union (IoU) and the Hausdorff distance in comparison with the gold standard. The second automated model measured the cortical thickness based on a three-dimensional (3D) model rendered from the segmentation results and presented a color visualization of the measurements. The IoU and Hausdorff distance showed high accuracy (0.870 and 0.928 for marrow bone and 0.734 and 1.247 for cortical bone, respectively). A visual comparison of the 3D color maps showed a similar trend to the gold standard. This algorithm for automatic segmentation of the mandibular condyle head and visualization of the measured cortical thickness as a 3D-rendered model with a color map may contribute to the automated quantification of bone thickness changes of the temporomandibular joint complex on CBCT.

Synovial entrapment in alloplastic temporomandibular joint replacement

Complications of alloplastic temporomandibular joint (TMJ) prostheses can lead to stress and anxiety for the patient and the surgical team, and prosthesis substitution is sometimes required. The aim of this case report is to describe the surgical finding of synovial entrapment with interposed fibrosis in a postoperative alloplastic TMJ revision, managed effectively with adequate surgical debridement. The authors believe that synovial entrapment needs to be considered as a possible postoperative complication of total joint replacement when no clear symptoms of infection, metal hypersensitivity, osteolysis, or heterotopic bone formation are present. The implications of synovial entrapment in TMJ alloplastic replacement remains relatively unpredictable and poorly understood.

Knee orthopedics as a template for the temporomandibular joint

Although the knee joint and temporomandibular joint (TMJ) experience similar incidence of cartilage ailments, the knee orthopedics field has greater funding and more effective end-stage treatment options. Translational research has resulted in the development of tissue-engineered products for knee cartilage repair, but the same is not true for TMJ cartilages. Here, we examine the anatomy and pathology of the joints, compare current treatments and products for cartilage afflictions, and explore ways to accelerate the TMJ field. We examine disparities, such as a 6-fold higher article count and 2,000-fold higher total joint replacement frequency in the knee compared to the TMJ, despite similarities in osteoarthritis incidence. Using knee orthopedics as a template, basic and translational research will drive the development and implementation of clinical products for the TMJ. With more funding opportunities, training programs, and federal guidance, millions of people afflicted with TMJ disorders could benefit from novel, life-changing therapeutics.

Temporomandibular Joint Prostheses: Optimal Materials for the Optimal Stomatognathic System Performance-Preliminary Study

The aim of this study was to quantitatively evaluate alloplastic Temporomandibular Joint (TMJ) Prostheses against other treatment modalities regarding the jaw kinematics. Six patients with Temporomandibular Joint Prostheses, four with mandibular ramus Patient-Specific Implant (PSI) with condylar head preservation, and four after mandibular condylectomy were evaluated by the means of axiography (Cadiax Compact 2), which is the noninvasive three-dimensional study of condylar movements. The patients were also evaluated clinically for the mandibular movements. The study revealed that the significant movement limitations occurred bilaterally in patients fitted with TMJ prosthesis. For the protrusion movement, the vector length of the movement (L) for the TMJ prosthesis was 0.31 vs. 3.01 mm for the PSI (Kruskal–Wallis chi-squared = 9.1667, df = 2, p-value = 0.01022, post hoc Dunn p-value = 0.015) and for the laterotrusion to the operated side, the length of the vector (L) was 0.66 vs. 3.35 mm, respectively. Statistically significant differences between groups were most frequent for the laterotrusion to the unoperated side. The study shows that a further development on TMJ Prostheses geometry and materials is needed.

Clinical and radiological outcomes of Chinese customized three-dimensionally printed total temporomandibular joint prostheses: A prospective case series study

PURPOSE

Temporomandibular joint (TMJ) diseases are highly prevalent in China. However, no commercialized custom-made prostheses are available now. This study introduces a three-dimensionally (3D) printed customized total TMJ prosthesis manufactured by a standardized workflow.

MATERIALS AND METHODS

Consecutive patients with end-stage TMJ diseases were recruited from Jan 2018 to Sep 2018. The computed tomography (CT) data for patients were obtained and transformed into the Mimics 18.0 software preoperatively for designing of prostheses and digital templates. 3D printing, friction spot welding and computer-assisted manufacture (CAM) were used to fabricate different components of the prosthesis. The clinical and radiographic evaluations were performed postoperatively.

RESULTS

A series of 9 patients were included. All the prostheses were placed smoothly and fixed stably during surgical procedure. Without severe postoperative complications, all patients exhibited significant improvements in maximum mouth opening, pain, diet, and mandibular function, with good facial symmetry. For the whole prosthesis, the average mean deviation was 0.432 mm (range: from 0.279 to 0.561 mm).

CONCLUSIONS

This study suggests that Chinese customized 3D-printed total TMJ prostheses produces excellent short-term clinical outcomes, with high accuracy in implantation.

Ankylosis of the temporomandibular joint-impression free CAD/CAM based joint replacement using patient-specific implants

In recent years, alloplastic temporomandibular joint (TMJ) replacement has become a permissible procedure for the reconstruction of severely destroyed TMJs. The use of computer-aided design/computer-aided manufacturing (CAD/CAM) has extended the range of applications to complex anatomical situations. The aim of the treatment is to improve the usually restricted mouth opening and thus oral hygiene and nutrition, which leads to a regular improvement in the general quality of life. The following case report describes the bilateral replacement of ankylotically destroyed TMJs using patient-specific endoprostheses with simultaneous displacement of the maxilla. Innovative in the case described is the impression-free CAD/CAM planning, whereby the upper and lower prostheses were produced on the basis of 3D printed patient models.

The healthcare burden and associated adverse events from total alloplastic temporomandibular joint replacement: a national United States perspective

The purpose of this study was to provide a United States perspective on alloplastic total joint replacement. We sought to estimate the inpatient burden and report the most common adverse events using two administrative datasets. The National Inpatient Sample was queried from October 2015 to December 2016 for total joint replacement admissions using International Classification of Diseases 10^th revision codes, and the Manufacturer and User Facility Device Experience registry was queried from January 2009 to September 2019 using manufacturer brands. The combined final sample included 114 inpatient admissions and 392 adverse events. Mean age was 43.1 years, and most patients were white (82.7%) and female (86.0%). The mean hospital charge was $108,709.43 and the mean length of stay was 2.6 days. The most common adverse events were infection (26.3%), heterotopic bone (20.9%), and poor intraoperative fit (14.0%). Fifty-four percent of cases had bilateral total joint replacements, 24.6% had simultaneous subcutaneous abdominal fat grafting, and 11.4% had simultaneous maxillary repositioning. Fat grafting and maxillary repositioning were not associated with any significant difference in the length of stay or cost. Compared to unilateral cases, bilateral total joint replacements carried significantly greater charges (P<0.01), but no increased length of stay (P=0.70), suggesting that bilateral and unilateral cases may experience a similar postoperative course.

Clinical guidelines for total temporomandibular joint replacement

Total joint replacement (TJR) of the temporomandibular joint (TMJ) is a promising surgical procedure and device for treating end-stage diseases of the TMJ. For the functional and aesthetic reconstruction of the oral and maxillofacial head and neck region, TMJ TJR significantly helps maintain the patient's quality of life in terms of a better diet, mastication, speech and social interaction. TMJ TJR was approved by regulatory authorities in 2019 in Japan, thus enabling the clinical application of the TJR system. However, the surgery demands particularly difficult and high-risk procedures, necessitating the prudent selection of indicated patients. The joint committee of the Japanese Society of Oral and Maxillofacial Surgeons and Japanese Society for Temporomandibular Joint is working together to develop an appropriate clinical guideline for TMJ TJR.

Total Temporomandibular Joint Replacement: Stick to Stock or Optimization by Customization?

Purpose

This article aims to compare the difference in postoperative results in patients treated with either a patient-specific (PSI) or a stock temporomandibular total joint replacement system.

Materials and Methods

The investigators performed a systematic review concerning postoperative results after placement of either a stock total joint replacement system or a PSI. PubMed Central, Web of Science, Cochrane Library Plus, Wiley Online Library, and EMBASE were used to conduct this search. All articles up to August 15, 2018, were scrutinized. All included articles were nonrandomized cohort studies. Maximal mouth opening (MMO) and Visual Analog Scale (VAS) scores for pain and diet before and after surgery were evaluated. The Methodological Index for NonRandomized Studies scale was used for quality assessment. Weighted mean difference was calculated and pooled by meta-analysis using random-effect models.

Results

The search identified 1581 articles, of which 15 were included. The average risk of bias was low. Both systems achieved significant increases in MMO and decreased VAS pain scores at 1, 2, and 3 years after surgery. No significant difference was found between the system types. Both achieved significant improvements in dietary VAS scores, with a more significant improvement for stock implants.

Conclusions

Due to the lack of detailed diagnostic evaluation tools allowing proper start-point categorization, there is a significant risk for selection bias in the pooled data. The PSI is more frequently chosen for cases with more significant joint degeneration, skewing postoperative results. A patient-fitted implant can provide significant operative and patient-centered advantages over a stock implant, which will likely be confirmed when observational cohort studies have included indications like the ones for stock prostheses. Furthermore, while current US Food and Drug Administration-approved stock implants contain cobalt -chromium -molybdenum, the newly manufactured PSI are made of titanium alloy, diminishing the risks of morbidity and implant failure.

Advancements in temporomandibular joint total joint replacements (TMJR)

The goal of this paper is to review the advantages and disadvantages of the various treatment options of temporomandibular joint (TMJ) total joint replacement (TJR). TMJ articles published within the last 20 years were reviewed to collect the information on non-invasive and invasive TMD treatment methods. Recent technological advancements helped the evolution of treatment methods and offered significant value to TMD patients and surgeons. Considering the TMD levels, the therapeutic procedures can involve general health examiniations, physical therapy, medication, oral rehabilation or as an end stage clinical invention, temporomandibular joint replacement. In fact when intra-articular TMD is present, the effective treatment method appears to be TJR. However, concern for infection, material hypersensitivity, device longevity and screws loosening issues still exists. Further combined research utilizing the knowledge and expertise of, surgeons, material scientists, and bioengineers is needed for the development of improved TMD therapeutic treatment.

Preliminary clinical study of Chinese standard alloplastic temporomandibular joint prosthesis

PURPOSE

To evaluate the preliminary clinical outcomes on the Chinese standard temporomandibular joint (TMJ) prostheses.

PATIENTS AND METHODS

Patients who underwent Zimmer Biomet and Chinese standard prostheses by one surgeon between January 1st 2016 and June 30th 2017 were included in the study. Maximum incisal opening (MIO), pain, diet, and joint function were measured; CT scans were taken before and after the operation and during at least a 12-months follow-up for evaluation.

RESULTS

Thirty-five patients including 12 with Chinese standard prostheses and 23 with Biomet stock prostheses participated in the study. After an average of 14.3 months follow-up, both types of prostheses could significantly improve MIO, diet, and joint function, and relieve pain (p < 0.05). There were no significant differences in diet, pain level and joint function either before or after the operation between the two types of prostheses, whereas after the operation, the MIO with Chinese standard prostheses was significantly larger than with the Biomet stock prostheses (p < 0.05). However, there was no significant difference before operation (p > 0.05). A computed tomography (CT) scan showed that no prostheses dislocated or broke, no screws loosened, and ectopic bone formation appeared around the alloplastic condyle.

CONCLUSION

Chinese standard TMJ prostheses are effective and stable in clinical application. They can significantly improve mouth opening, diet, and joint function and relieve pain.

Prevention and detection of prosthetic temporomandibular joint infections-update

Prosthetic joint infections are not only distressing complications for patients and surgeons, but also have an enormous financial impact on healthcare systems. The reported incidence of prosthetic joint infection is likely underestimated due to difficulties in their diagnosis. This unfortunate complication has challenged joint replacement surgeons for years, despite all the advances made in this surgical discipline. Since eradication of these infections can be very difficult, prevention remains the primary objective. Identifying recipient risk factors, adopting a proper surgical technique, appropriate wound care, optimizing the operating room environment, and appropriate postoperative care have become some of the core elements that can help to minimize the overall incidence of this complication. The purpose of this article is to provide the temporomandibular joint replacement surgeon with an update on the prevention and detection of prosthetic joint infections based on a review of the most recent information published in the orthopedic and surgical literature.

Temporomandibular Joint Reconstruction in the Growing Child

Indications and considerations for reconstruction of the temporomandibular joint (TMJ) differ between growing and skeletally mature patients. Osteoarthritis, which is the most common cause of TMJ destruction in adults, is comparatively rare in children. The most common indications in young patients are congenital deformities, pathology, ankylosis and progressive resorptive processes. Options for reconstruction include distraction osteogenesis, autologous reconstruction (ie, costochondral graft, free fibula flap), and total alloplastic joint replacement. The choice of the ideal reconstruction is based on multiple factors, which include extent and laterality of the deformity, patient age, jaw growth pattern, and potential for progressive destruction.

Biomechanical evaluation of Chinese customized three-dimensionally printed total temporomandibular joint prostheses: A finite element analysis

PURPOSE

This work aims to evaluate the biomechanical behavior of Chinese customized three-dimensional (3D)-printing total temporomandibular joint (TMJ) prostheses by means of finite element analysis.

METHODS

A 3D model was established by Mimics 18.0, then output in a stereolithography (STL) format. Two models were established to investigate the strain behaviors of an intact mandible and a one-side implanted mandible respectively. Hypermesh and LS-DYNA software were used to establish computer-aided engineering finite element models. The stress distribution on the custom-made total TMJ prosthesis and the strain distribution on the mandible were analyzed by loading maximal masticatory force.

RESULTS

The maximum stress on the surface of the ultra-high-molecular weight polyethylene was 19.61 MPa. With respect to the mandibular component, the maximum stress in the mandibular component was located at the anterior and posterior surface of the condylar neck, reaching 170.01 MPa. The peak von Mises stress was observed on the topside screw of the mandible, which was found to be 236.08 MPa. For the intact model, it was observed that the strain distribution was basically symmetrical. For the model with the prosthesis, the curve of strain distribution was fundamentally consistent with that in the intact mandible, except for the last 24 mm along the control line. A prominent strain decrease between 41.4% and 58.3% was observed in this area.

CONCLUSIONS

Chinese customized 3D-printed total TMJ prostheses exhibit uniform stress distribution without changing the behavior of the opposite side natural joint. Furthermore, the prostheses have a great potential to be improved in design and materials with a promising future.

Temporomandibular Joint Disorders in Older Adults

OBJECTIVES

To review the literature and summarize the evidence of temporomandibualar joint (TMJ) disorders (TMDs) in older adults, focusing on clinical manifestations of TMDs in older adults, highlighting the incidence and sexual dimorphism of TMJ degeneration and the role of sex hormones in this process, and providing potential treatment options for TMD in older adults.

DESIGN

Two review authors performed the literature search, study inclusion, and data extraction. PubMed, Embase, and Google scholar were searched for literature until August 2017 (Figure ). We adopted a combination of Medical Subject Headings with related free text words for the search in PubMed and optimized the search in other search engines.

RESULTS

Traditionally, it was believed that TMDs predominantly affected women of childbearing age, but recent large studies in Europe and the United States have shown that the prevalence of TMD peaks after childbearing age (45-64) and then gradually decreases with age, although not much is known about the disease in older adults.

CONCLUSION

Most older adults have TMJ degeneration, which affects women more than men. In most older adults, the symptoms of TMD are mild and self-limiting and can usually be treated with self management.

Temporomandibular joint regeneration: proposal of a novel treatment for condylar resorption after orthognathic surgery using transplantation of autologous nasal septum chondrocytes, and the first human case report

Background

Upon orthognathic mandibular advancement surgery the adjacent soft tissues can displace the distal bone segment and increase the load on the temporomandibular joint causing loss of its integrity. Remodeling of the condyle and temporal fossa with destruction of condylar cartilage and subchondral bone leads to postsurgical condylar resorption, with arthralgia and functional limitations. Patients with severe lesions are refractory to conservative treatments, leading to more invasive therapies that range from simple arthrocentesis to open surgery and prosthesis. Although aggressive and with a high risk for the patient, surgical invasive treatments are not always efficient in managing the degenerative lesions.

Methods

We propose a regenerative medicine approach using in-vitro expanded autologous cells from nasal septum applied to the first proof-of-concept patient. After the required quality controls, the cells were injected into each joint by arthrocentesis. Results were monitored by functional assays and image analysis using computed tomography.

Results

The cell injection fully reverted the condylar resorption, leading to functional and structural regeneration after 6 months. Computed tomography images showed new cortical bone formation filling the former cavity space, and a partial recovery of condylar and temporal bones. The superposition of the condyle models showed the regeneration of the bone defect, reconstructing the condyle original form.

Conclusions

We propose a new treatment of condylar resorption subsequent to orthognathic surgery, presently treated only by alloplastic total joint replacement. We propose an intra-articular injection of autologous in-vitro expanded cells from the nasal septum. The proof-of-concept treatment of a selected patient that had no alternative therapeutic proposal has given promising results, reaching full regeneration of both the condylar cartilage and bone at 6 months after the therapy, which was fully maintained after 1 year. This first case is being followed by inclusion of new patients with a similar pathological profile to complete an ongoing stage I/II study.

Trial registration

This clinical trial is approved by the National Commission of Ethics in Medical Research (CONEP), Brazil, CAAE 12484813.0.0000.5245, and retrospectively registered in the Brazilian National Clinical Trials Registry and in the USA Clinical Trials Registry under the Universal Trial Number (UTN) U1111–1194-6997.

Electronic supplementary material

The online version of this article (10.1186/s13287-018-0806-4) contains supplementary material, which is available to authorized users.

Alloplastic reconstruction of the temporomandibular joint

Temporomandibular joint reconstruction (TMJR) is often necessary for patients with severe and/or refractory TMJ disease who have failed conservative treatment. TMJR aids to improve masticatory function and is associated with improved quality of life outcomes. Currently, alloplastic reconstruction is considered as the treatment of choice in most severe TMJ disorders due to its many advantages inclusive but not limited to early mobilization, stable longterm results, and significant improvement in jaw function. Broadly speaking, two types of TMJR prostheses are available for reconstruction: 1) stock, and, 2) custommade prostheses. The purpose of this article is to provide the reader with a brief overview of the basic principles and fundamentals of TMJR while referencing pertinent existing literature.