Maximum voluntary bite force in patients with alloplastic total TMJ replacement – A prospective study

Alloplastic temporomandibular total joint replacement (TJR) for end-stage disease, congenital disorders and following ablative oncological surgery has been shown to reduce pain and improve function. The purpose was to assess the maximum voluntary bite force and maximum interincisal opening (MIO) in patients undergoing alloplastic total temporomandibular joint replacement (TJR).Seventeen patients with different diagnoses resulting in condylar hypomobility (8 patients; 15 joints) and condylar instability (9 patients; 12 joints) had undergone alloplastic TMJ reconstruction. Maximum voluntary bite force and MIO were measured at pre-operatively (T0), 2 (T1), 6 (T2) and 12 (T3) months. For ordinal data comparison at different time-points, the Wilcoxon signed-ranks test was used.There was a significant improvement in maximum voluntary bite force for both, patients with condylar hypomobility (P = 0.003) and condylar instability (P = 0.007). Analysis of MIO revealed a significant improvement at T3 (P = 0.002).Alloplastic TJR would appear to increase maximum voluntary bite force and MIO. Biomechanical integrity of the stomatognathic system and the ability of the patient to triturate food could be improved by alloplastic temporomandibular joint (TMJ) replacement.     

Groningen temporomandibular total joint prosthesis: An 8-year longitudinal follow-up on function and pain

Total temporomandibular joint replacement is a surgical procedure for patients with severe temporomandibular joint afflictions affecting quality of life, which have not responded beneficially to previous conventional surgery. The aim of this study was to assess the long-term outcome of the Groningen temporomandibular joint (TMJ) prosthesis in patients with chronic pain and mutilated temporomandibular joints following multiple surgical procedures, with respect to prosthesis failure, the patient's postoperative level of satisfaction and longitudinal changes in maximum mouth opening, functional mandibular impairment and pain. Eight female patients were studied in whom Groningen TMJ prostheses were inserted, two unilaterally and six bilaterally.The Groningen TMJ prosthesis was mechanically successful during 8 years of follow-up in seven out of eight patients with a disc dislocation being seen in one patient (7%). Patients were satisfied, despite the limited improvement of the maximum mouth opening, and pain scores.Although the decline of MFIQ scores during 8 years of follow-up was significant compared to baseline (p = 0.027), the effects of the prosthesis on maximum mouth opening, function and pain were limited. This may be due to persistent chronic pain and the adverse effects of multiple previous surgical procedures.     

Temporomandibular joint arthroscopy in advanced stages of internal derangement: a retrospective cohort study on the influence of age

The aim of this investigation was to evaluate the outcomes of patients with advanced internal derangement of the temporomandibular joint who underwent operative arthroscopy, according to age stratified into two groups: <45 years and ≥45 years. The study included a series of 194 patients. Outcome variables were pain intensity and mandibular mobility. Additionally, the difference in arthroscopic findings in these age groups was studied. The data analysis included the paired t-test, χ² test, and two-way analysis of variance, with a P-value <0.05 indicating statistical significance. A significant reduction in pain and an improvement in maximum inter-incisal opening (MIO) was observed in both groups starting at 1 month of follow-up (P < 0.01). However, the results for MIO were worse in the ≥ 45 years group (P = 0.036) at 12- and 18-months follow-up. Regarding arthroscopic findings, the study showed a higher prevalence of severe chondromalacia in the ≥45 years group (P = 0.031) and disc displacement without reduction in the <45 years group (P = 0.020). Analysis of variance showed a greater pain reduction if no obliteration of the articular space was observed (P = 0.039). In young and older patients, operative arthroscopy can be useful for short-term treatment in advanced stages of internal derangement of the temporomandibular joint.     

Study on the lateral pterygoid muscle status after artificial temporomandibular joint replacement

The purpose of this study was to explore the status of the lateral pterygoid muscle (LPM) after detachment in artificial temporomandibular joint replacement (TJR) surgery. Patient clinical and computed tomography imaging data were collected before and after unilateral artificial TJR with LPM detachment. The volume of the LPM on the operated and unoperated sides was measured before and after surgery (at 1, 3, 6, 12 months) using ProPlan CMF 3.0 software. The volumes of the LPM on both sides, the patient’s mandibular movements, quality of life (QoL), and pain and diet scores (visual analogue scales) were evaluated and compared at the different follow-up stages. Ten patients were included in the study. After surgery, the volume of the operated LPM was significantly reduced to 60.78% at 3 months (P = 0.007), and gradually stabilized to 51.58% at 6 months (P = 0.025) and 54.68% at 1 year postoperative (P = 0.002). There were no significant LPM volume changes on the unoperated side (P = 0.67). Lateral movement of the operated joint was significantly reduced (P = 0.021) and correlated with the LPM volume change after surgical detachment (P = 0.042). The LPM shrank after detachment in the artificial TJR surgery and the muscle detachment affected the movement of the replaced joint.     

Relationship between temporomandibular joint pain and magnetic resonance imaging findings in patients with temporomandibular joint disorders

The purpose of this study was to evaluate abnormal magnetic resonance imaging (MRI) findings related to temporomandibular joint (TMJ) pain. This study included 245 joints of 152 patients with temporomandibular disorders with anterior disc displacement; of these, 129 joints had joint pain whereas 116 joints had no joint pain. MRI was used to evaluate the reduction of anterior disc displacement, joint effusion, mandible condylar morphology, bone marrow oedema of the mandibular condyle, and signal intensity of the posterior disc attachment (PDA) on fat-suppressed T2-weighted images. The odds ratio (OR) for each MRI variable for the pain group versus the no pain group was computed using logistic regression analysis. Univariate logistic regression analysis showed significant correlations between TMJ pain and all MRI findings. Multivariate logistic regression analysis showed significant correlations with joint effusion (P = 0.03, OR 2.21), bone marrow oedema (P < 0.001, OR 11.75), and signal intensity of the PDA (P < 0.001, OR 6.21). These results suggest that bone marrow oedema, high signal intensity of the PDA on fat-suppressed T2-weighted images, and joint effusion, in descending order of influence, are factors related to TMJ pain.     

A ten-year experience and follow-up of three hundred patients fitted with the Biomet/Lorenz Microfixation TMJ replacement system

The purpose of this paper is to present the postoperative results obtained after full temporomandibular joint (TMJ) reconstruction employing the Biomet/Lorenz Microfixation TMJ replacement system (Jacksonville, FL, USA) in 300 patients (201 unilateral, 99 bilateral). Objective data (maximum inter-incisal opening; MIO) and subjective data (function and speech, diet, and pain) were collected preoperatively and at postoperative evaluations performed over a 10-year period (mean 3.5, standard deviation 2.1 years). The MIO measures were obtained using a calliper rule. Subjective data were evaluated using a visual analogue scale with scores ranging from 0 to 5 for each variable. The results were analyzed with the paired t-test (two-sided, α = 5%). Each patient showed significant improvements for all of the variables at evaluation on postoperative day 7. The results for MIO, function and speech, and diet, showed improvements at each postoperative evaluation over a maximum of 3 years, with stabilization of the results from the fourth year. Complaints of pain decreased considerably up to the 1-month postoperative evaluation, and no patient reported severe pain at 6 months after surgery. The results presented show that the reconstruction of the TMJ through the installation of the Biomet/Lorenz system prosthesis is a safe and effective option for proper reestablishment of the joint and stomatognathic system function; significant long-term improvements in mandibular range of motion are promoted and pain levels decrease.     

Relationships between disk displacement,joint effusion,and degenerative changes of the TMJ in TMD patients based on MRI findings

This study was performed to investigate the relationships between disk displacement, joint effusion, and degenerative changes in patients with temporomandibular disorders using MRI. Randomly selected MRIs of 508 temporomandibular joints of 254 patients (92 males and 162 females, mean age was 30.5 ± 12.0 years) were reviewed retrospectively. Seventy-eight percent (198 out of 254) of the patients complained of joint pain. Compared with joints with a normal disk position, the joints with anterior disk displacement with reduction showed a 2.01 odds ratio (P < 0.01) of degenerative changes and a 2.85 odds ratio (P < 0.001) of joint effusions. The joints with anterior disk displacement without reduction showed a 4.43 odds ratio (P < 0.001) of degenerative changes and a 4.61 odds ratio (P < 0.001) of joint effusions. These results clearly show that the risk of degenerative changes and joint effusions increase with displacement of the disk position in patients with temporomandibular disorders. Although all disk displacement situations do not progress to painful joints and/or degenerative joint diseases, the possibility of an increased risk of progression by a breakdown in the balance between a patient’s adaptive capacity and functional loading of the TMJ should be assessed in each and every patient through comprehensive evaluation of various contributing factors.     

A cohort study of patients with juvenile idiopathic arthritis and arthritis of the temporomandibular joint: outcome of arthrocentesis with and without the use of steroids

The purpose of this study was to evaluate the effects of intra-articular temporomandibular joint (TMJ) treatment in patients with juvenile idiopathic arthritis (JIA). The inclusion criteria were met by 21 patients (38 joints). Joints were randomly selected for either arthrocentesis alone (n = 17) or arthrocentesis with the additional use of triamcinolone hexacetonide (n = 21) using a closed single-needle system. Measurements of pain and function were performed at baseline and at follow-up after 3 and 8 months. Pain on opening and lateral excursion improved significantly after injections. Pain decreased significantly from baseline to first and second control on a visual analogue scale (VAS) for overall pain (49–18–8) and overall function (41–19–4). Significant improvement was recorded for pain on palpation of muscles and joints. There was no statistically significant difference between the treatment modalities, with or without glucocorticoid injection. Arthrocentesis in the TMJ treatment of patients with JIA may be beneficial and steroids had no additional effect. Further studies are needed to evaluate the long-term effects on the TMJ structures and on condylar growth from arthrocentesis and intra-articular steroid injections.     

Temporomandibular joint replacement: a New Zealand perspective

Alloplastic total temporomandibular joint replacement (TMJ TJR) has been performed in New Zealand utilizing the TMJ Concepts patient-fitted system since 2000. The data analysed in this study were collected retrospectively from questionnaires sent to all maxillofacial surgeons in New Zealand who had implanted TMJ Concepts devices between 2000 and 2011. A total of 63 devices were implanted in 42 patients (13 males, 29 females) during this 12-year period. The primary indication for TMJ TJR was end-stage joint disease resulting from ankylosis and arthritis. The mean age of the patients was 47 years (range 7–80 years). The most common complication reported was transient facial nerve impairment in 4.8% of the patients. Objective results, measured as the maximal incisional opening, improved by a mean of 17.3 mm (P < 0.01); 90% of patients reported improved quality of life. New Zealand oral and maxillofacial surgeons have concluded that TMJ TJR using the TMJ Concepts prosthesis is a reliable treatment option for the management of end-stage TMJ disease.     

Reconstruction of the temporomandibular joint: a comparison between prefabricated and customized alloplastic prosthetic total joint systems

The implantation of an alloplastic total temporomandibular joint (TMJ) prosthesis is an innovative approach for the treatment of end-stage TMJ disorders. Two types of system exist: prefabricated (stock) and customized computer-aided design/computer-aided manufacturing (CAD/CAM) devices. A clinical study was performed to evaluate the effectiveness of these two designs. Twenty-eight patients treated between 2015 and 2017 were included and assigned to two groups: stock prostheses (group 1) and customized CAD/CAM prostheses (group 2). Clinical evaluations were performed at five time-points up to 6 months postoperative. Parameters included maximum interincisal opening, pain, diet, complications, and subjective well-being at the end of follow-up. Differences between pre-surgery and 6-month post-surgery values were highly significant (P < 0.001). No patient required a liquid diet at the end of treatment, and 66% of group 1 patients and 100% of group 2 patients reported improved well-being. Complications were observed in 32% of patients and included temporary paralysis of the facial nerve. In conclusion, clinical outcomes of stock and CAD/CAM prostheses suggested great improvements in mouth opening and reduction of pain as a result of the rehabilitation of TMJ function. Results showed comparable data for the two types of prosthesis design at 6 months postoperative.     

Strategies to reduce re-ankylosis in temporomandibular joint ankylosis patients

The purpose of the study was to define a protocol for the prevention of re-ankylosis after surgical management of temporomandibular joint ankylosis (TMJA). The investigators designed a retrospective study on all TMJA patients treated with different treatment modalities from 2013 to 2019. The investigators observed that complete removal of the ankylotic mass particularly on the medial side; use of a piezoelectric scalpel for a clean and smooth osteotomy with copious irrigation to remove bone chips and slurry; less trauma to the local tissue; osteotomy design parallel and inferior osteotomy at the narrowest part, which mostly corresponds to the condylar neck; performance of a coronoidectomy (if mouth opening is <30 mm), fat interposition; no intraoperative correction of any pre-existing chin deviation when treated with costochondral graft; patient motivation; and aggressive physiotherapy, and use of a vacuum drain are all important to prevent re-ankylosis, irrespective of the treatment modality. A total of 114 patients (n = 152 joints), [bilateral (n = 38), unilateral (n = 76)] were evaluated retrospectively. Interpositional arthroplasty with fat was performed in n = 43, CCG was used for reconstruction in n = 30 and total joint replacement (TJR) was done in n = 41 patients. Re-ankylosis was seen in n = 3 (2.6%) patients (2 in CCG and 1 patient in interpositional arthroplasty). The follow-up ranged from 12-80 months. The results conclude that following the suggested best practice protocol is effective in reducing re-ankylosis.     

Does closed treatment of paediatric mandibular condyle fractures result in restitutional remodelling?

The treatment of paediatric mandibular condylar fracture (PMCF) is typically non-operative. The purpose of this study was to determine if non-operative management of PMCF results in a new condylar process of normal morphology to regenerate after closed treatment (restitutional remodelling). The specific aim of the study was to observe restitutional remodelling (RM) in PMCF and review the literature. The investigators designed and implemented a retrospective study on paediatric patients (age < 12) with unilateral or bilateral condyle fractures treated with non-operative treatment between January 2005 and July 2015. Patients with complete records and at least 1-year follow-up were included in the study. Primary outcome variable was RM and secondary outcome variables were occlusion, maximal incisal opening (MIO), displacement, infection, facial asymmetry, and signs of temporomandibular joint ankylosis (TMJA). The study evaluated 41 patients {n = 57 PMCF, (m:f-35:6)} of unilateral (n = 25) and bilateral (n = 16) PMCF. Fractured condyles remodelled to normal morphology in all the cases at follow-up. The Wilcoxon test revealed a statistically significant difference in MIO from the preoperative value to postoperative (p = 0.001). Occlusion (except 1) was satisfactory in all cases, at follow-up with no gross facial asymmetry. There was no sign of infection at the surgical site (anterior mandible). None of the patients showed signs of TMJA at follow-up. The result of the present study demonstrates that RM of condylar fracture occurs with non-operative management. Non-operative management should be the point of care in PMCF, owing to the rapid RM, bone regeneration, and satisfactory outcome. Review of the literature also supports closed treatment.     

Analysis of outcomes after revision replacement of failed total temporomandibular joint prostheses

End-stage disease of the temporomandibular joint (TMJ) can be managed successfully with alloplastic total replacements, but these can fail because of allergy, infection, wear, fracture, and heterotopic development of bone. We prospectively reviewed the outcome data of all patients who required revision of previously placed replacement joints between 2004 and 2016. Data included pain and diet scores using 100 mm visual analogue scales (VAS), and interincisal distance recorded before, and at six weeks, six months and 12 months after operation. The reasons for failure and the number of previous procedures were also noted.Twenty patients (26 joints) had revisions. The reasons included infection (n = 9), reankylosis (n = 5), wear of the existing prosthesis (n = 2), fracture of the prosthesis (n = 2), foreign body reaction (n = 1), and allergy to the prosthesis (n = 1). The mean (range) age of the patients was 53.3 (47-68) years, and 15 were female and five male. Preoperatively, the mean (SD) pain score was 73.1 (22.4), mouth opening was 20.9 (10.2) mm, and diet score 41.7 (23.6). At 12-month follow up, all the measurements had improved significantly (p ≤ 0.05), with the pain score improving to a mean (SD) of 18.4 (25.2), mouth opening to 32.2 (9.3) mm, and diet score to 89.4 (18.5). Revision replacements done by an experienced team result in considerably improved outcomes with limited complications, but the improvements in function and pain are not as marked as they are after primary replacement.     

Will they fit? Determinants of the adaptability of stock TMJ prostheses where custom TMJ prostheses were utilized

Currently only two alloplastic temporomandibular joint (TMJ) total joint replacement (TJR) systems are available in the United States. The aim of this study was to define variables that determine whether a Biomet stock prosthesis could have been used to reconstruct a TMJ previously reconstructed with a TMJ Concepts patient-fitted prosthesis. All of the TMJ Concepts prostheses placed between 2010 and 2018 at the University of Texas – Health at San Antonio were analyzed retrospectively. There were 128 cases (241 joints) with intact stereolithographic models analyzed for successful adaptation of the Biomet stock TMJ prosthesis. Anatomical, demographic, etiological, and perioperative data were gathered for each joint to investigate possible causes of failure of stock adaptation. The majority of joints, 74% (178/241), could have had a stock prosthesis adapt. All joints with ≥40 mm gap arthroplasty failed stock prosthesis adaptation. Only 50% (32/64) of the joints with at least one previous open TMJ surgery and 60% (58/96) of the joints with concomitant orthognathic surgery could have had a stock TMJ prosthesis. The stock prosthesis could not be adapted for any of the patients requiring TMJ replacement for congenital disorders or those requiring TMJ salvage. Overall, the majority of cases treated with a patient-specific TMJ TJR could have been treated with a stock prosthesis.     

Intraoperative real-time navigation and intraoperative three-dimensional imaging for patient-specific total temporomandibular joint replacement

Customized solutions for replacement of the temporomandibular joint (TMJ) along with surgical guides enable precise and fast transfer of the virtual plan to the patient. However, these guides lack information on screw vectors and length, and well-defined borders for bony resections towards the medial skull base. This retrospective study was performed to investigate the feasibility and benefit of real-time navigation and intraoperative three-dimensional imaging during total TMJ replacement (TJR), as well as patient clinical outcomes. Between 2016 and 2020, 26 customized prostheses were implanted in 21 patients either with or without real-time navigation and instrument tracking. The clinical, surgical, radiological, and navigational data were analysed. The accuracy of navigation registration with instrument tracking, precision of screw insertion, and implant and screw positions were analysed by fusion of the virtual plan and surgical outcome. Real-time navigation aided orientation during lateral skull base dissection and resection. However, the results of real-time navigation-aided drilling were inconclusive regarding vector and length control. At a mean 15.3 ± 3.0 months of follow-up, average mouth opening had improved from 21.69 ± 2.80 mm to 36.40 ± 1.25 mm; the average pain score decreased from 6.18 ± 0.74 to 1.06 ± 0.52. Thus, intraoperative real-time navigation for TJR assists lateral skull base dissection and resection.     

Efficiency of arthrocentesis treatment for different temporomandibular joint disorders

This study was performed to determine whether arthrocentesis therapy has different outcomes in three groups of patients with different temporomandibular disorders (TMDs). A clinical trial was conducted including 45 patients with 45 unilaterally affected joints divided into three groups (n = 15): osteoarthritis (OA), disc displacement with reduction (DDWR), and disc displacement without reduction (DDWoR). All patients underwent the same arthrocentesis treatment protocol. The outcome variables, including visual analogue scale evaluations and measurements of mandibular motion (in millimetres), were recorded at baseline and at 1 and 6 months postoperative. Inter-group assessments showed significant short-term differences in joint sounds (P = 0.016) and significant long-term differences in masticatory efficiency (P = 0.046) and protrusive movement (P = 0.048). The estimation of mean changes between baseline and long-term follow-up revealed significant differences in joint sounds (P < 0.001), disruption in daily activities (P = 0.002), maximum mouth opening (P = 0.008), and protrusive movement (P = 0.002) between the groups. Arthrocentesis therapy may be useful to improve clinical symptoms and range of mandibular movement in patients with all three types of TMD. However, the benefit of arthrocentesis may be greater for patients with DDWoR than for those in the other groups.     

Long-term evaluation of single-puncture temporomandibular joint arthrocentesis in patients with unilateral temporomandibular disorders

The purpose of this study was to evaluate the long-term effects of the single-puncture arthrocentesis (SPA) technique. Forty-two patients with unilateral temporomandibular joint disorders (TMDs) were treated by SPA. Thirty-eight of these patients completed 1–24 months of follow-up (short-term group) and 21 completed 11 months or longer of follow-up (long-term group). The two groups were evaluated statistically for pain (visual analogue scale), maximum mouth opening, lateral excursion, and protrusion. Both follow-up duration groups showed significant improvements when compared to baseline levels for almost all of the outcome variables (P < 0.05). Single puncture temporomandibular joint arthrocentesis is an effective treatment method over both the short and long term.     

Benign temporomandibular joint tumours with extension to infratemporal fossa and skull base: condyle preserving approach

This article introduces a modified surgical approach combining condylotomy with posterior disc attachment release for the resection of large non-malignant masses located in the infratemporal fossa and involving the skull base. This retrospective study included 14 patients treated at Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University between January 2010 and December 2016. Clinical evaluations (visual analogue scale (VAS) for pain, maximum inter-incisal opening (MIO), and complications) and radiological findings (magnetic resonance imaging (MRI) and computed tomography (CT)) were collected pre- and postoperatively. All patients had satisfactory surgical exposure and complete resection of the neoplasms. During an average follow-up of 54.8 months, no clinical or radiographic signs of recurrence were reported. MIO increased from 28 mm preoperatively to 35.4 mm postoperatively (P < 0.001). The pain VAS score changed from 5.4 preoperatively to 0.7 postoperatively (P < 0.001). Neural function was normal for all patients. Postoperative MRI and CT scans showed a satisfactory disc position and condyle morphology, with no resorption. Three-dimensional reconstruction of the postoperative CT scan also demonstrated healing of the skull base defects. The modified surgical approach combining condylotomy with posterior disc attachment release is suitable for the removal of large non-malignant masses involving the infratemporal fossa and skull base.     

Total reconstruction of the temporomandibular joint. Up to 8 years of follow-up of patients treated with Biomet® total joint prostheses

12 patients underwent temporomandibular joint (TMJ) reconstruction with Biomet total joint prostheses. Indications for TMJ reconstruction included ankylosis, rheumatoid arthritis, degenerative joint disease and condylar resorption. Five patients had unilateral procedures, seven had bilateral. The follow-up ranged between 2 and 8 years. Amongst the ankylotic patients the mean jaw-opening capacity increased from 3.8 mm preoperatively to 30.2 mm 1 year after surgery, and in most of those patients the opening capacity remained stable over the years. The other patients maintained a mean opening capacity of more than 35 mm. Joint related pain and interference with eating were eliminated after TMJ reconstruction. There were no permanent facial nerve disturbance, no postoperative infections and no device related complications. The outcome supports prosthetic TMJ reconstruction as a useful treatment modality in patients with advanced TMJ disease.     

Alterations of mandibular movement patterns after total joint replacement: a case series of long-term outcomes in patients with total alloplastic temporomandibular joint reconstructions

According to recognized guidelines, a total alloplastic replacement may be indicated to resolve temporomandibular pain and functional limitations in cases where conservative and less aggressive surgical management strategies have failed. It is broadly believed that, as a result of the surgical procedure, the function of the lateral pterygoid muscle is lost and so are the laterotrusive and protrusive jaw movements. Furthermore, the joint prosthesis design may not be conducive to lateral and protrusive movements. Using a dynamic stereometry technique, it was possible to perform a quantitative analysis of kinematics in TJR patients. The cases of four patients who showed preserved lateral and/or protrusive motion are presented here. During mouth opening, prosthetic condyle translation ranged from 3.18 mm to 10.09 mm and it was also possible to observe this clinically. It has been suggested that changes in prosthesis design may have improved postoperative jaw kinematics. Considering the large diversity in treatment outcomes, it is recommended that the individual prognosis should always be discussed with the patient prior to surgery.