Long-term outcomes after total alloplastic temporomandibular joint reconstruction following exposure to failed materials

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.

Chondrogenic potential of superficial versus cartilage layer cells of the temporomandibular joint condyle in photopolymerizable gelatin-based hydrogels

The objectives of this study were to compare the chondrogenic potential of cells derived from different layers of Mandibular condyle cartilage and to gain further understanding of the impact of chondrogenic cues when embedded into a novel hydrogel scaffold (PGH, a polymer blend of poly (ethylene glycol), gelatin, and heparin) compared to a gelatin hydrogel scaffold (GEL). Cartilage layer cells (CLCs) and fibroblastic superficial layer cells (SLCs) were harvested from the mandibular condyle of boer goats obtained from a local abattoir. After expansion, cells were seeded into PGH and GEL hydrogels and cultured in chondrogenic media for 3 weeks. Scaffolds were harvested at 0, 1, and 3 week(s) and processed for gross appearance, histochemical, biochemical, and mechanical assays. In terms of chondrogenesis, major differences were observed between scaffold materials, but not cell types. Glycosaminoglycan (GAG) staining showed GEL scaffolds deposited GAG during the 3 week period, which was also confirmed with the biochemical testing. Moreover, GEL scaffolds had significantly higher compressive modulus and peak stress than PGH scaffolds at all time points with the largest difference seen in week 3. It can be concluded that GEL outperformed PGH in chondrogenesis. It can also be concluded that materials play a more important role in the process of chondrogenesis than the tested cell populations. Fibroblastic SLCs were shown to have similar chondrogenic potential as CLCs cells, suggesting a rich pool of progenitor cells in the superficial fibroblastic layer capable of undergoing chondrogenesis given appropriate physical and chemical cues.

Virtual Surgical Planning for Temporomandibular Joint Reconstruction with Stock TMJ Prostheses: Pilot Study

The temporomandibular joint (TMJ) is one of the most complex joints in the human anatomy. In advanced degenerative stages, conservative or minimally invasive surgical therapies have failed to restore joint function, and joint replacement with prostheses has been required. Stock prostheses, compared to custom-made prostheses, are much less expensive and require less pre-operative preparation time. Four patients followed for years for temporomandibular dysfunction and previously operated on by arthroscopy or open joint surgery that have been reconstructed with stock TMJ prostheses (STMJP) through virtual surgical planning (VSP) and an STL model with surgical and positioning guides were included. The median follow-up was 15 months; the median number of previous TMJ surgeries was 2. The mean preoperative MIO was 24.6 mm and at longest follow-up was 36.4 mm. The median preoperative TMJ pain score was 8, and the median postoperative TMJ pain was 3. All patients have improved their mandibular function with a clear improvement of their initial situation. In conclusion, we believe that stock TMJ prostheses with virtual surgical planning and surgical guides are a good alternative for TMJ reconstruction at the present time. Nonetheless, prospective and randomized trials are required with long-term follow up to assess their performance and safety.

Total temporomandibular joint reconstruction prosthesis in hemifacial microsomia: A systematic review

Hypoplastic asymmetry due to hemifacial microsomia (HFM) often represents the most difficult reconstruction in the craniomaxillofacial clinic. Although autogenous grafts are generally used for temporomandibular joint reconstruction (TMJR), the use of TMJR prostheses is not well established. The aim of this review was to identify, collect and analyse the use of extended TMJR (eTMJR) prostheses in patients with HFM, describing clinical features, surgical procedures and postoperative complications. Online searches of all major databases were performed according to PRISMA guidelines. All studies with HFM patients treated with the eTMJR prostheses were included. Descriptive statistics were used for data analysis. A total of 19 studies, including 08 case studies, 06 case series and 05 retrospective cohort studies, met the inclusion criteria, where a total of 42 HFM patients were reported from 18 countries, mostly from the United States (05; 26%). Fifteen of the 42 cases (~36%) were male. The mean ± SD (range) age of patients in all studies was 19.79 ± 5.81 (9-36) years. The mean ± SD (range) of patient follow-up was 41.30 ± 35.50 (6-136) months. A total of 5 (10.6%) patients were implanted with bilateral eTMJR prostheses. The Pruzansky classification was used in 18 (~89.5%) studies, OMENS classification in 01 (~5%) study, whereas no classification was reported in one study. Only 01 (7.1%) study had documented the eTMJR classification for the prosthesis used. In growing patients with or without a history of failed autogenous tissues, TMJR prostheses may provide a viable alternative. Randomized studies with large cohorts are warranted to validate these preliminary results.

Is the risk of chronic pain after total temporomandibular joint replacement independent of its indications? A prospective cohort study

Chronic pain is a possible long-term complication after alloplastic temporomandibular joint reconstruction (TMJR). This study was developed to evaluate various subjective and objective measurements to determine the presence and degree of TMJ pain in patients treated with TMJR regardless of the indication for the operation. A prospective, single-centre study was performed. Data on 36 patients (56 TMJR) were collected preoperatively and at follow up two to three years postoperatively. The primary outcome variable was subjective TMJ pain (none/mild, moderate/severe) at follow up. The predictor variables were objective pressure pain thresholds (PPTs) at the ipsilateral joint(s) and muscle(s), functional parameters (incisal range of motion, maximum voluntary clenching), subjective oral health-related quality of life (OHRQoL), and demographic and surgical variables. The number of patients with moderate/severe pain decreased from 17 preoperatively to 10 at follow up. Self-reported TMJ pain was significantly reduced in the entire group (p = 0.001). Patients with moderate/severe pain at follow up were more restricted in their OHRQoL but did not differ in PPT and functional parameters from the no/mild pain group. Moderate/severe TMJ pain at follow up was associated with unilateral TMJR and more preoperative pain. This study provides preliminary evidence that despite good pain reduction in most patients, persistent pain after TMJR is common and, in rare cases, may even worsen regardless of the original diagnosis. At follow up there was a close relation between OHRQoL and TMJ pain. TMJ pain after TMJR cannot be confirmed by objective measurement methods (PPTs and functional parameters).

Reconstruction of the TMJ and condyle in inflammatory arthritis

Inflammatory arthritis presents a unique destructive process to the temporomandibular joint. This article provides information on the proper diagnosis, treatment planning, and surgical management aimed to provide patients with improvement in pain, function, stability and facial aesthetics. Additionally, it aims to provide a detailed insight on the joint reconstruction options including alloplastic joint replacement, autogenous joint replacement, orthognathic surgery and distraction osteogenesis.

Reasons for failure of total temporomandibular joint replacement: a systematic review and meta-analysis

The aim of this study was to evaluate the revision rate after total alloplastic temporomandibular joint replacement (TMJR) and determine whether there is a higher risk of revision surgery with stock or custom-fitted prostheses (the two most current TMJR prosthesis types). A systematic review was performed, with a search of PubMed, Google Scholar, and the Cochrane Library in November 2020. Overall, 27 articles were included in this study, describing Biomet and TMJ Concepts prostheses and including postoperative data on complications requiring a return to the operating room. A total of 2247 prostheses were analysed: 1350 stock Biomet prostheses and 897 custom-fitted TMJ Concepts and custom-fitted Biomet prostheses. The global revision rate was 1.19 per 100 prosthesis-years. The most common reason for revision was heterotopic bone formation. Stock prostheses appeared to have a lower risk of revision compared to custom prostheses: rate ratio 0.52 (95% confidence interval 0.33-0.81, P-value 0.003). Regarding causes of revision, the only significant difference between the types of devices was a higher rate of heterotopic bone formation for custom-made prostheses (P = 0.001). The results of this study revealed a low revision rate post TMJR revision, with stock devices even less prone to such risk. Nevertheless, these results can be explained by the fact that custom-made prostheses are more likely to be used for cases in which the anatomy is significantly abnormal or there is a history of multiple joint surgeries, which carry a greater risk of complications and heterotopic bone formation.

Orthognathic surgery for juvenile idiopathic arthritis of the temporomandibular joint: a critical reappraisal based on surgical experience

Juvenile idiopathic arthritis (JIA) involving the temporomandibular joint (TMJ) can result in significant dentofacial deformities that may require orthognathic surgical correction. The aim of this study was to assess the functional and aesthetic results relative to stability after bimaxillary surgery with counterclockwise rotation of the occlusal plane in patients with JIA. A retrospective chart review was conducted of all patients affected by JIA who underwent orthognathic surgery between January 2000 and December 2019 at the Face Surgery Centre (Parma, Italy). Patient records were evaluated for surgical indications, complications, and outcomes. The final study sample included 13 patients (12 female, one male). The mean age of the patients was 18.6 years (range 17-26 years) at the time of surgery; 12 patients had bilateral TMJ disease. At the 1-year follow-up, all patients except one had a stable occlusion with a natural, well-balanced morphology of the face and adequate dynamic excursion of the mandible. The 1-year postoperative cone beam computed tomography (CBCT) scan revealed complete ossification at all osteotomy sites. Bilateral sagittal split osteotomy with mandibular advancement is an effective procedure with a low rate of complications for patients with JIA with stable disease confirmed by preoperative CBCT or magnetic resonance imaging.

Can Patients With Metal Hypersensitivity Requiring TMJ Total Joint Prostheses be Successfully Treated With All-Titanium Alloy Mandibular Components?

PURPOSE

Patients with documented metal hypersensitivity to cobalt-chromium-molybdenum (CoCrMo) alloy with trace nickel requiring TMJ total joint prosthesis (TJP) may have adverse reactions to the metals in the standard TMJ Concepts TJP. This study aimed to determine if these patients can be successfully treated by eliminating CoCrMo alloy and constructing the mandibular components of all-titanium (Ti) alloy.

PATIENTS AND METHODS

This retrospective cohort study evaluated metal hypersensitive patients (MHG) that received the TMJ Concepts TJP modification of all-Ti alloy mandibular components with outcome results compared to a control group (CG) of non-metal-sensitive patients that received the standard TMJ Concepts prostheses. The primary predictor variables were the 2 groups, MHG and CG. Primary variables evaluated using Likert scales included TMJ pain, headache, jaw function, diet, and disability. Maximum incisal opening and quality of life were measured. Secondary variables included: age, gender, effect of the number and type of prior TMJ. Scores for pre- and postsurgery parameters (nonparametric variables) were analyzed using a Mann-Whitney U test (α = 0.05).

RESULTS

The MHG (n = 30) received the Ti alloy TJP and CG (n = 46) received the standard TJP, with statistically significant improvements in all variables in both groups and no statistically significant difference in outcome variables between the 2 groups. Patients with 0 to 1 previous TMJ surgeries had better outcomes in all parameters except maximum incisal opening compared to patients with 2 or more previous TMJ surgeries.

CONCLUSIONS

Patients with documented hypersensitivity to CoCrMo alloy, requiring TMJ Concepts TJP may experience improvement in TMJ pain, headache, jaw function, diet, disability, jaw opening, and quality of life when the mandibular components are manufactured from all-Ti alloy, eliminating the CoCrMo alloy. The larger the number of previous TMJ surgeries and exposure to failed alloplastic implants, the less improvement in treatment outcomes.

A Minimally Invasive Approach for Temporomandibular Joint Replacement: A Pilot Study

Temporomandibular joint replacement (TJR) with an alloplastic (metal/ultra-high-molecular-weight polyethylene) device has proven to be a successful and predictable procedure. This paper describes a novel technique for performing TJR with an endaural incision alone. The technique we are describing uses only an endaural incision with supplemental trocar incision(s), to perform a TJR. There were 4 patients for a total of 8 temporomandibular joints that were selected. All 4 patients were assessed immediately following surgery, on postoperative days 1 and 7 and at 6 months following surgery. Maximal interincisal opening and subjective variables were assessed at each of the time points. Additionally, the total operative time was measured and compared to a previous age and diagnosis matched control group using the traditional 2 incisions TJR.There were 3 females and 1 male (ages 19-67) who underwent TJR with an endaural incision alone. There were 4 females (ages 19-68) who underwent traditional TJR surgery. None of the patients in either group had major complications and all patients were discharged on postoperative day 1. All patients in the endaural incision alone group had increased maximal interincisal opening and reported a quicker subjective decrease in pain and disability following surgery with less average time in the operating room. However, all patients in the endaural incision alone group had CN VII weakness that lasted longer than those in the traditional TJR group.The minimally invasive approach for TJR was successful in the present pilot study and could be used in specific situations to decrease the morbidity associated with additional incisions for this procedure. Ultimately, the endaural only incision approach offers promising outcomes for future patients undergoing temporomandibular joints TJR in the right patient population.

Transitioning to chronic temporomandibular disorder pain: A combination of patient vulnerabilities and iatrogenesis

Background

Based on a variety of studies conducted in recent years, some of the factors that might contribute to the negative treatment responses of some TMD patients have been elucidated.

Methods

This paper describes known vulnerability factors that make individuals susceptible to developing temporomandibular disorders (TMDs), as well as those that contribute to the perpetuation of such problems. In addition, the topic of iatrogenesis is discussed as a major contributor to the negative outcomes that can be seen in this field.

Results

At the patient level, anatomical, psychosocial and genetic factors may contribute to individual vulnerability. The anatomy and pathophysiology of muscles, joints, disc and nerves may all be involved in predisposing to TMD symptoms, especially when the patients have pain elsewhere in the body. Among the psychosocial factors, some features may be elucidated by the DC/TMD axis II, while others (eg illness behaviour, Munchausen syndrome, lack of acceptance of non‐mechanical approaches) require careful evaluation by trained clinicians. Genetic predisposition to first onset TMDs and to chronification of symptoms has been identified for individuals with certain psychological traits, presence of comorbid conditions and certain abnormal clinical manifestations. Regarding iatrogenesis, sins of omission may influence the clinical picture, with the main ones being misdiagnosis and undertreatment. Joint repositioning strategies, occlusal modifications, abuse of oral appliances, use of diagnostic technologies, nocebo effect and complications with intracapsular treatments are the most frequent sins of commission that may contribute to chronification of TMDs. The patients who present with massive occlusal and jaw repositioning changes combined with persistent severe orofacial pain are not a rarity within TMD and orofacial pain canters; these patients are the most difficult ones to manage because of this horrific combination of negative factors.

Conclusions

The information presented in this paper will help clinicians to understand better why some individuals develop temporomandibular disorders, why some of them will progress to becoming chronic patients, and what the appropriate responses may be.

Role of Custom-Made Prosthesis for Temporomandibular Joint Replacement in Unilateral Ankylosis - An Evaluative Study

Introduction

Ankylosis is a physically and psychologically distressing condition to a patient. The aim of this study was to evaluate the efficiency of custom-made temporomandibular joint (TMJ) prosthesis (fossa-condyle component) in patients with unilateral ankylosis in restoring the form and functions of the TMJ.

Materials and Methods

This retrospective study was conducted in ten patients with unilateral TMJ ankylosis who had undergone TMJ reconstruction with custom-made TMJ prosthesis. Clinical parameters assessed were maximal mouth opening, lateral movements, improvement of the pain levels, and dietary efficiency of the patient. The data were analyzed using SPSS version 20 (IBM Corporation, SPSS Inc.; Chicago, IL, USA).

Results

The mean preoperative mouth opening was 5.70 ± 3.62 mm. After gap arthroplasty, it was 32.50 ± 3.31 mm. The postoperative mouth opening after the reconstruction of TMJ using alloplastic joint prosthesis was 34.90 ± 2.69 mm, and after a mean follow-up period of 4 years, the mean postoperative mouth opening was 34.60 ± 2.50 mm. The mean preoperative movement toward the right and left side was 0.9 ± 1.2 mm and 1.3 ± 1.25 mm, respectively. The mean right and left lateral movements of the TMJ after reconstruction were 3.5 ± 0.97 mm and 3.70 ± 1.06 mm, respectively. There was decrease in deviation of the unaffected jaw during mouth opening and closure. Functional occlusion was maintained postoperatively. There was no appreciable change in the visual analog pain scales. The dietary efficiency improved from a scale of 10 (liquids) to a scale of 0 (no restriction to diet) in eight patients and 1 in two patients. The dietary score improved significantly after alloplastic reconstruction (P = 0.000). No evidence of facial nerve paralysis or foreign body reactions was noted in the patients during the follow-up period. Radiographic assessment revealed good positioning and adaptation of the fossa component and the condylar ramal component both postoperatively and after a mean 4-year follow-up period. There was no evidence of screw loosening or prosthesis breakage during the follow-up period.

Discussion and Conclusion

The custom-made TMJ-total joint replacement (TJR) devices provide stable, improved long-term results, thereby increasing the quality of life of the patient. The custom-made alloplastic TMJ-TJR prosthesis proves to be the optimal surgical procedure to reconstruct the TMJ in comparison to the autogenous grafts (to avoid complications) in severe degenerated and ankylosed joints. However, long-term clinical and radiological studies on a larger sample size are imperative to establish the versatility of this procedure.

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.

Outcome of eminectomy combined with discectomy and silastic interpositional graft for temporomandibular joint dysfunction: a retrospective study of 20 years

Internal derangement of the temporomandibular joint (TMJ) is usually treated conservatively, but about 5% require surgical treatment. We designed a retrospective study to assess the long-term outcomes of eminectomy combined with discectomy and silastic interpositional graft in 44 patients who had chronic TMJ dysfunction that had not responded to traditional conservative treatment and arthrocentesis. The maximum mouth opening, pain score, Wilkes stage, and clinical dysfunction index were measured before, and two years after, operation. All the patients showed significant improvement in mouth opening and reduced pain scores (p<0.0001 in each case). There were no long-term operative complications, and postoperative magnetic resonance scans showed that the silastic interpositional graft was in a stable position with no evidence of degenerative changes on the surfaces of the joint and no lymphadenopathy.

Longitudinal management of recurrent temporomandibular joint ankylosis from infancy to adulthood in perspective of surgical and orthodontic treatment

This study was performed to describe the longitudinal management of recurrent temporomandibular joint (TMJ) ankylosis from infancy to adulthood in perspective of surgical and orthodontic treatment. A 2-year-old girl was referred with chief complaints of restricted mouth opening and micrognathia due to bilateral TMJ ankylosis. For stage I treatment during early childhood (6 years old), high condylectomy and interpositional arthroplasty were performed. However, TMJ ankylosis recurred and symptoms of obstructive sleep apnea (OSA) developed. For stage II treatment during early adolescence (12 years old), gap arthroplasty, coronoidectomy, bilateral mandibular distraction osteogenesis, and orthodontic treatment with extraction of the four first premolars were performed. However, TMJ ankylosis recurred. Because the OSA symptoms reappeared, she began to use a continuous positive airway pressure device. For stage III treatment after completion of growth (20 years old), low condylectomy, coronoidectomy, reconstruction of the bilateral TMJs with artificial prostheses along with counterclockwise rotational advancement of the mandible, genioglossus advancement, and orthodontic treatment were performed. After stage III treatment, the amount of mouth opening exhibited a significant increase. Mandibular advancement and ramus lengthening resulted in significant improvement in the facial profile, Class I relationships, and normal overbite/overjet. The OSA symptoms were also relieved. These outcomes were stable at the one-year follow-up visit. Since the treatment modalities for TMJ ankylosis differ according to the duration of ankylosis, patient age, and degree of deformity, the treatment flowchart suggested in this report could be used as an effective guideline for determining the appropriate timing and methods for the treatment of TMJ ankylosis.

The Use of Patient-Specific Implants in Oral and Maxillofacial Surgery

This article summarizes the current use of patient-specific implants in oral and maxillofacial surgery.

The effectiveness of the surgical correction of the temporomandibular joint intracapsular disorders

Background. The prevalence of temporomandibular joint diseases covers about 40% of the population. The main place (from 70 to 82%) among these diseases is occupied by the so-called intracapsular disorders of the temporomandibular joint (TMJ). The lack of consensus on the use of treatment methods and clear protocols for the rehabilitation of patients with intracapsular TMJ disorders was the basis for the conduct of this study. Objective. The purpose of the study was to analyze the treatment effectiveness in patients with intracapsular disorders of the temporomandibular joint using the complex of pathogenetically substantiated conservative and surgical methods. Methods. The research included 43 patients with complaints to pains and dysfunction of TMJ. Everything fulfilled the uniform protocol of inspection. Depending on disease degree to patients were assigned or a course of conservative treatment with use splint therapy, or surgical correction of defect. Results. After analyzing the dynamics of patient treatment in the framework of this study, it was found that surgical correction of intracapsular disorders of the temporomandibular joint was effective in all patients examined by us. Conclusion. To maintain a long-term stable result, this group of patients is shown orthodontic-orthopedic rehabilitation, with the goal of creating and maintaining correct occlusal relationships.

Salvage or Solution: Alloplastic Reconstruction in Hemifacial Microsomia

INTRODUCTION

Skeletal reconstruction in severe grades of hemifacial microsomia (HFM) continues to be challenging. Traditional techniques of autografts and osseous distraction for reconstruction of the glenoid fossa, condyle, and ramus can fall short of expectations and can create new problems. This intercontinental study analyzes the role of alloplastic skeletal rehabilitation in severe HFM.

METHODS

Ten consecutive patients with Pruzansky grade III HFM were reconstructed between October 2014 and July 2017 at 2 craniofacial centers following the same protocol. Data were gathered retrospectively from the medical records, including photographs and virtual planning records. Pre and postoperative photos were taken to compare occlusal status, interincisal opening, sagittal mandibular projection, and posterior facial height. Alloplastic reconstruction was accomplished using a custom designed titanium implant.

RESULTS

Ten consecutive skeletally mature patients with HFM with failed traditional reconstructions were successfully treated with virtually planned alloplastic reconstructions (11 joints) and simultaneous orthognathic surgery. The glenoid fossa, condyle, and ramus on the affected sides were reconstructed with custom designed titanium implants. All patients achieved occlusal stabilization, normalization of posterior facial height and sagittal mandibular projection, and maintenance or improved inter-incisal opening. There were no major complications or repeated surgeries. Follow-up ranges from 6 to 50 months.

CONCLUSION

Alloplastic reconstruction allows for precise vertical reconstruction of the ramus and condyle and sagittal repositioning of the mandibular body. The glenoid fossa component is firmly anchored to the skull base assuring a stable centric relation on the reconstructed side. Consistent and acceptable results can be achieved in skeletally mature patients.

Improved anchoring nails: design and analysis of resistance ability : Tensile test and finite element analysis (FEA) of improved anchoring nails used in temporomandibular joint (TMJ) disc anchor

Background

Anchorage is one of the most important treatments for severe temporomandibular joint disorder (TMD). Anchoring nails have shown great success in clinical trials; however, they can break under pressure and are difficult to remove. In this study, we aimed to evaluate an improved anchoring nail and its mechanical stability.

Methods

The experiment consisted of two parts: a tensile test and finite element analysis (FEA). First, traditional and improved anchoring nails were implanted into the condylar cortical bone and their tensile strength was measured using a tension meter. Second, a three-dimensional finite element model of the condyles with implants was established and FEA was performed with forces from three different directions.

Results

The FEA results showed that the total force of the traditional and improved anchoring nails is 48.2 N and 200 N, respectively. The mean (±s.d.) maximum tensile strength of the traditional anchoring nail with a 3–0 suture was 27.53 ± 5.47 N. For the improved anchoring nail with a 3–0 suture it was 25.89 ± 2.64 N and with a 2–0 suture it was above 50 N. The tensile strengths of the traditional and improved anchoring nails with a 3–0 suture was significantly different (P = 0.033–< 0.05). Furthermore, the difference between the traditional anchoring nail with a 3–0 suture and the improved anchoring nail with a 2–0 suture was also significantly different (P = 0.000–< 0.01).

Conclusion

The improved anchoring nail, especially when combined with a 2–0 suture, showed better resistance ability compared with the traditional anchoring nail.

Foreign Body Giant Cell Reaction to a Proplast/Teflon Interpositional Implant: A Case Report and Literature Review

After discectomy, interpositional implants (IPIs) are believed to provide temporomandibular joint stability and protect against degenerative joint space remodeling. Alloplastic IPIs gained popularity in the late 1970s because the practice showed early success without donor site morbidity. Unfortunately, these implants were subject to substantial fragmentation resulting in an exuberant foreign body giant cell response that progressively eroded adjacent structures. Most of these alloplastic implants were removed in the years following their recall by the US Food and Drug Administration in 1991, however some remained in circulation. This report describes a case of a failed Proplast/Teflon IPI 27 years after its placement. This case highlights the considerations for managing a patient with a Proplast/Teflon IPI and serves to remind providers that, although increasingly rare, these implants are still present and subject to delayed failure.

Reconstruction of the Adult Hemifacial Microsomia Patient with Temporomandibular Joint Total Joint Prosthesis and Orthognathic Surgery

Background

HFM patients' reconstruction has always been a challenge for maxillofacial surgeons, and numerous reconstructive techniques have been described. Surgical treatment depends on the patient's age and contemplates Temporomandibular Joint (TMJ) reconstruction in conjunction with orthognathic surgery, usually necessary following completion of growth to maximize the functional and esthetic results. Distraction osteogenesis had gained popularity as valid alternative in growing patients, but the two primary methods to reconstruct the TMJs involve the use of autogenous, using free or microvascular bone grafts, or alloplastic graft, but there is no widely accepted method.

Methods

The increasing use of temporomandibular prosthesis for temporomandibular problems has led us to use them even in HFM. A case of female nongrowing patients with HFM type IIb treated with temporomandibular prosthesis in an all-in-one protocol is presented.

Results

Incisal opening, measured with BioPAK system (Bioresearch Inc., Milwaukee, USA), was 21.4 mm in the presurgical period and 32.2 mm after all-in-one procedure, for an increase of 50.5%. Excursive movement to the right side was 2.2 mm in the presurgical period and was 1.5 mm after surgery, for a decrease of 31.8%. Left excursion movement changed from 5 mm to 6.1 mm, for an increase of 22.0%.

Conclusions

The TMJ Concepts patient-fitted TJP in conjunction with orthognathic surgery for TMJ and jaw reconstruction is a valid option for patients with HFM.

Bioengineered Temporomandibular Joint Disk Implants: Study Protocol for a Two-Phase Exploratory Randomized Preclinical Pilot Trial in 18 Black Merino Sheep (TEMPOJIMS)

BACKGROUND

Preclinical trials are essential to test efficacious options to substitute the temporomandibular joint (TMJ) disk. The contemporary absence of an ideal treatment for patients with severe TMJ disorders can be related to difficulties concerning the appropriate study design to conduct preclinical trials in the TMJ field. These difficulties can be associated with the use of heterogeneous animal models, the use of the contralateral TMJ as control, the absence of rigorous randomized controlled preclinical trials with blinded outcomes assessors, and difficulties involving multidisciplinary teams.

OBJECTIVE

This study aims to develop a new, reproducible, and effective study design for preclinical research in the TMJ domain, obtaining rigorous data related to (1) identify the impact of bilateral discectomy in black Merino sheep, (2) identify the impact of bilateral discopexy in black Merino sheep, and (3) identify the impact of three different bioengineering TMJ discs in black Merino sheep.

METHODS

A two-phase exploratory randomized controlled preclinical trial with blinded outcomes is proposed. In the first phase, nine sheep are randomized into three different surgical bilateral procedures: bilateral discectomy, bilateral discopexy, and sham surgery. In the second phase, nine sheep are randomized to bilaterally test three different TMJ bioengineering disk implants. The primary outcome is the histological gradation of TMJ. Secondary outcomes are imaging changes, absolute masticatory time, ruminant time per cycle, ruminant kinetics, ruminant area, and sheep weight.

RESULTS

Previous preclinical studies in this field have used the contralateral unoperated side as a control, different animal models ranging from mice to a canine model, with nonrandomized, nonblinded and uncontrolled study designs and limited outcomes measures. The main goal of this exploratory preclinical protocol is to set a new standard for future preclinical trials in oromaxillofacial surgery, particularly in the TMJ field, by proposing a rigorous design in black Merino sheep. The authors also intend to test the feasibility of pilot outcomes. The authors expect to increase the quality of further studies in this field and to progress in future treatment options for patients undergoing surgery for TMJ disk replacement.

CONCLUSIONS

The study has commenced, but it is too early to provide results or conclusions.

Reconstruction of nongrowing hemifacial microsomia patient with custom-made unilateral temporomandibular joint total joint prosthesis and orthognathic surgery

A case of hemifacial microsomia in a young male is presented. The ascending ramus and condyle was reconstructed utilizing virtual 3D planning with a custom-made total TMJ device (TMJ Concepts, USA) in combination with conventional orthognathic surgery. The alternative available reconstructive options are discussed and the advantages and disadvantages of the technique selected.

Total temporomandibular joint replacement prostheses: a systematic review and bias-adjusted meta-analysis

The aim of the present study was to determine which prosthesis has resulted in the best outcomes after total temporomandibular joint replacement (TMJR). A comprehensive electronic search was undertaken in September 2015. Inclusion criteria encompassed studies that described one of the three current TMJR systems and that had pre- and postoperative data on at least two of the following TMJR indications: pain, diet, function, and maximum inter-incisal opening (MIO). Sixteen papers were included in the systematic review, reporting 10 retrospective studies and six prospective studies (no randomized controlled or case-controlled trials). A total 312 patients with 505 TMJ Concepts prostheses, 728 patients with 1048 Biomet prostheses, and 125 patients with 196 Nexus prostheses were included in the analysis. There was no real difference between the various TMJR systems in terms of pain or diet scores. Function scores improved with the TMJ Concepts, but this was the only prosthesis for which data were available. Biomet prostheses appeared to have a greater increase in MIO mean gain compared to TMJ Concepts and Nexus prostheses; however this was heavily biased by one study. Without this study, there was no real difference in MIO. It is concluded that the prostheses are similar, but most data are available for the TMJ Concepts prosthesis, with results being favourable.

Potential Indications for Tissue Engineering in Temporomandibular Joint Surgery

PURPOSE

Musculoskeletal 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.

FINDINGS

There 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.

CONCLUSIONS

Biomedical 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.

Tissue engineering of the temporomandibular joint disc: current status and future trends

INTRODUCTION

Temporomandibular joint disorders are extremely prevalent and there is no ideal treatment clinically for the moment. For severe cases, a discectomy often need to be performed, which will further result in the development of osteoarthritis. In the past thirty years, tissue engineering has provided a promising approach for the effective remedy of severe TMJ disease through the creation of viable, effective, and biological functional implants.

METHODS

Although TMJ disc tissue engineering is still in early stage, unremitting efforts and some achievements have been made over the past decades. In this review, a comprehensive summary of the available literature on the progress and status in tissue engineering of the TMJ disc regarding cell sources, scaffolds, biochemical and biomechanical stimuli, and other prospects relative to this field is provided.

RESULTS AND CONCLUSIONS

Even though research studies in this field are too few compared to other fibrocartilage (e.g., knee meniscus) and numerous, difficult tasks still exist, we believe that our ultimate goal of regenerating a biological implant whose histological, biochemical, and biomechanical properties parallel native TMJ discs for clinical therapy will be achieved in the near future.

Methotrexate pharmacotherapy for implant-related temporomandibular joint pain: a case report

This article presents a patient experiencing several years of pain associated with bilateral failed temporomandibular joint (TMJ) Proplast/Teflon fossa prostheses. Despite surgical removal of the prostheses and comprehensive conservative management, including typical pharmacotherapy approaches for chronic pain, pain was still not relieved, and management was revised to target a putative chronic inflammatory disorder. Methotrexate was prescribed because of its known efficacy for inflammation and pain reduction in rheumatoid arthritis. Titration of methotrexate dosage over 5 months to a weekly dose of 20 mg resulted in reduced pain intensity at rest, increased pain-free maximal jaw opening, and a reduction in the sensory component of the McGill Pain Questionnaire. Maximum assisted jaw opening remained the same, as did the palpation tenderness of both TMJs and of the masseter and temporalis muscles. Methotrexate pharmacotherapy may represent a viable option when conservative treatments have failed to provide significant pain relief in patients who have had Proplast/Teflon TMJ implants.

Autologous adipose stem cells and polylactide discs in the replacement of the rabbit temporomandibular joint disc

The temporomandibular joint (TMJ) disc lacks functional replacement after discectomy. We investigated tissue-engineered bilayer polylactide (PLA) discs and autologous adipose stem cells (ASCs) as a potential replacement for the TMJ disc. These ASC discs were pre-cultured either in control or in differentiation medium, including transforming growth factor (TGF)-β1 for one week. Prior to implantation, expression of fibrocartilaginous genes was measured by qRT-PCR. The control and differentiated ASC discs were implanted, respectively, in the right and left TMJs of rabbits for six (n = 5) and 12 months (n = 5). Thereafter, the excised TMJ areas were examined with cone beam computed tomography (CBCT) and histology. No signs of infection, inflammation or foreign body reactions were detected at histology, whereas chronic arthrosis and considerable condylar hypertrophy were observed in all operated joints at CBCT. The left condyle treated with the differentiated ASC discs appeared consistently smoother and more sclerotic than the right condyle. The ASC disc replacement resulted in dislocation and morphological changes in the rabbit TMJ. The ASC discs pre-treated with TGF-β1 enhanced the condylar integrity. While adverse tissue reactions were not shown, the authors suggest that with improved attachment and design, the PLA disc and biomaterial itself would hold potential for TMJ disc replacement.

Functional outcomes in bilateral temporomandibular joint ankylosis treated with stock prosthesis

The purpose of this study was to evaluate the functional outcomes in patients affected by bilateral temporomandibular joint (TMJ) ankylosis treated with TMJ total alloplastic reconstruction with stock prosthesis. As a matter of fact, ankylosis of the TMJ may produce the narrowing of the oropharyngeal airway space resulting in the obstructive sleep apnea syndrome, a pathological condition characterized by repetitive upper airway obstructions during sleep, resulting in arousal from sleep, sleep fragmentation, arterial oxygen desaturation. and daytime hypersomnolence.Clinical results demonstrate that total TMJ reconstruction with prosthesis is the surgical modality of choice to obtain the counterclockwise rotation and the advancement of the maxillomandibular complex, which significantly increase the volume of the oropharyngeal airway space in this kind of patients.