Current concepts in the pathogenesis of traumatic temporomandibular joint ankylosis

Is YouTube a reliable source of information for temporomandibular joint ankylosis?

PURPOSE

In the digital era, the internet is the go-to source of information, and patients often seek insights on medical conditions like TMJ ankylosis. YouTube, a popular platform, is widely used for this purpose. However, YouTube's lack of regulation means it can host unreliable content. Hence, the primary objective of this study is to assess the scientific quality of YouTube videos concerning TMJ ankylosis.

MATERIALS AND METHODS

This study analyzed 59 TMJ ankylosis-related videos. Two Oral and Maxillofacial Surgery specialists assessed these videos. Data on the video source, duration, upload date, the time elapsed since upload, total views, likes, dislikes and comments, Interaction index, and viewing rate were collected and analyzed. Video quality was assessed using the Global Quality Scale (GQS) and the Quality Criteria for Consumer Health Information (DISCERN), comparing health professionals and non-health professionals.

RESULTS

Health professional's videos were better in terms of GQS 3.21 ± 0.94 and DISCERN score 3.03 ± 0.75 as compared to the non-health professional videos GQS 3.0 ± 1.04, and DISCERN 2.81 ± 1.13. Health professional group videos had more reliability and better quality than the non-health professional group (p < 0.01).

CONCLUSION

YouTube should not be relied on as a trustworthy source for high-quality and reliable information regarding TMJ ankylosis videos. Healthcare professionals must be prepared to address any ambiguous or misleading information and to prioritize building trustworthy relationships with patients through accurate diagnostic and therapeutic processes.

Alloplastic TMJ replacement in the skeletally immature patient - A systematic review

This study assessed the current evidence for the use of TMJR reconstruction in skeletally immature patients. A systematic review was conducted according to PRISMA guidelines. An electronic search in PubMed and Embase was performed. Meta-analysis randomized controlled trials (RCTs), cohort studies, observational studies, case series, and case reports were eligible for inclusion. Case reports were also included due to the limited number of publications identified with the predefined terms. Exclusion criteria were: (1) studies written in a language other than English; (2) full-text unavailability (i.e., posters and conference abstracts). The selected studies were assessed for risk of bias. A meta-analysis was not performed as it necessitates a substantial between-study design homogeneity; hence, a descriptive synthesis of data was performed. There were 9 TMJR device reconstruction studies involving 14 subjects 13 years of age or younger. Follow-up ranged from 7 months to 120 months. All papers reported significant decrease in pain and improvement of diet. All prostheses were functional. No material failures of the prosthesis components were observed. The mandible continued to show limited growth following TMJR and most of the cases required no secondary or revision surgery even when the patient reached skeletal maturity. This systematic review had some limitations. The studies included had a low level of evidence and a high risk of bias. Most of the studies had a small patient sample, and no study had a control group. The literature reviewed supports the use of TMJR devices in the restoration of mandibular function and form in skeletally immature patients.

Peri-articular bone formation involving the temporomandibular joint: a narrative summary and Delphi consensus of a new classification system

Heterotopic ossification (HO) is defined as 'bone where it does not belong'. Given the historical variety of nomenclature and eponyms, there is significant confusion about the etiology, pathogenesis, classification, and treatment of HO related to the temporomandibular joint (TMJ). The existing classifications for TMJ HO have shortcomings: they relate to specific populations, use differing imaging studies and demographic data, do not universally include alloplastic/autologous replacements, are based variously on radiological and/or clinical presentations that cannot always be combined, and were largely developed to assist oral and maxillofacial surgeons in surgical management. These deficiencies make it problematic to compare studies, draw valid conclusions, and pursue research. The aim of this study was to develop a new, more inclusive classification for TMJ HO. Currently available classifications were evaluated and a Delphi-type system used to build consensus from clinicians and researchers to develop a new system. Fourteen unique classifications for TMJ ankylosis/HO were identified. In light of the biological specifics related to heterotopic calcification of extracellular matrix versus heterotopic formation of actual bone, the group recommends a more unambiguous term - peri-articular bone formation - and proposes a new classification. This will help clinicians and researchers to study, describe, and manage various types of ectopic bone associated with the TMJ.

The role of physiotherapy interventions in the management of temporomandibular joint ankylosis: a systematic review and meta-analysis : Running title: Physiotherapy in TMJ ankylosis

BACKGROUND

The main aim of this systematic review and meta-analysis was to identify peer-reviewed scholarly journal articles reporting the significance of physiotherapy interventions in managing TMJ ankylosis. In addition, this study aimed to critically appraise the existing evidence on the prevalence and clinical presentation, physiotherapy intervention approaches, efficacy of physiotherapy interventions, adverse effects, and safety of physiotherapy interventions in TMJ ankylosis management.

METHODS

An all-inclusive literature search was conducted using the PubMed, Google Scholar, and Scopus electronic databases. The researchers screened the potential articles and assessed for eligibility based on the reported inclusion and exclusion criteria. The quality evaluation tool for observational cohort and cross-sectional studies developed by the National Institutes of Health (NIH) and the Cochrane Collaboration's Risk of Bias Tool were used to assess the quality of the included studies. Researchers also comprehensively analyzed the data, reported the results, and discussed them according to the predominant themes.

RESULTS

The primary electronic database search yielded 409 articles, of which 25 were included in this review. A secondary search was conducted from citations of the included studies, yielding 74 articles, of which six were included in the study. A significantly higher prevalence of bony ankylosis than fibrous ankylosis, with an overall effect size of p < 0.00001. In addition, there were significantly more unilateral than bilateral presentations with an overall effect size of p < 0.00001. Moreover, there were 78 reported complications out of 245 subjects according to five included studies demonstrating a significant effect size with p = 0.001 following the treatment protocols.

CONCLUSION

This study highlighted the prevalence of bony ankylosis in temporomandibular joint ankylosis, emphasizing its impact on patients' well-being. On the other hand, the results show that physiotherapy is essential to optimize postoperative outcomes and minimize adverse events such as re-ankylosis. Practitioners and healthcare professionals must monitor postoperative recovery and ensure strict adherence to physiotherapy protocols for optimal outcomes.

Temporal gene expression profiling during early-stage traumatic temporomandibular joint bony ankylosis in a sheep model

BACKGROUND

Investigating the molecular biology underpinning the early-stage of traumatic temporomandibular joint (TMJ) ankylosis is crucial for discovering new ways to prevent the disease. This study aimed to explore the dynamic changes of transcriptome from the intra-articular hematoma or the newly generated ankylosed callus during the onset and early progression of TMJ ankylosis.

METHODS

Based on a well-established sheep model of TMJ bony ankylosis, the genome-wide microarray data were obtained from samples at postoperative Days 1, 4, 7, 9, 11, 14 and 28, with intra-articular hematoma at Day 1 serving as controls. Fold changes in gene expression values were measured, and genes were identified via clustering based on time series analysis and further categorised into three major temporal classes: increased, variable and decreased expression groups. The genes in these three temporal groups were further analysed to reveal pathways and establish their biological significance.

RESULTS

Osteoblastic and angiogenetic genes were found to be significantly expressed in the increased expression group. Genes linked to inflammation and osteoclasts were found in the decreased expression group. The various biological processes and pathways related to each temporal expression group were identified, and the increased expression group comprised genes exclusively involved in the following pathways: Hippo signaling pathway, Wnt signaling pathway and Rap 1 signaling pathway. The decreased expression group comprised genes exclusively involved in immune-related pathways and osteoclast differentiation. The variable expression group consisted of genes associated with DNA replication, DNA repair and DNA recombination. Significant biological pathways and transcription factors expressed at each time point postoperatively were also identified.

CONCLUSIONS

These data, for the first time, presented the temporal gene expression profiling and reveal the important process of molecular biology in the early-stage of traumatic TMJ bony ankylosis. The findings might contributed to identifying potential targets for the treatment of TMJ ankylosis.

Management of temporo-mandibular joint ankylosis using different surgical approaches

Comparison of gap arthroplasty (GAP), interpositional arthroplasty (IAP) and distraction osteogenesis (DO) simultaneous with interpositional arthroplasty (DO+IAP) in management of TMJ ankylosis is of interest to dentists. The study comprised 36 individuals with TMJ ankylosis, 16 of whom were female and 20 of whom were male. Both prior to and following surgery, the maximum inter-incisal opening (MIO) and facial pattern were noted. The postoperative MIO was 33.23 ± 1.23mm, 35.24 ± 1.11mm and 38.24 ± 1.34mm in GAP, IAP and DO+IAP respectively. Data is statistically significant with high MIO observed in DO+ IAP technique and low MIO in GAP technique (p < 0.005). In addition to lengthening the mandible, concurrently processed interpositional arthroplasty alongside DO for TMJ ankylosis corrects gross asymmetry of the face, occlusal mal-alignment, midline change, and creates room for previously un-erupted teeth to emerge.

Complications of Mandibular Fracture Repair

Mandible fracture management has evolved dramatically. Therefore, the variety of surgical complications associated with mandibular fractures, and their incidences, have continued to change as well. This article aims to assess the most common and most concerning complications that can occur secondary to management of mandibular fractures by examining categories of complication types. This article also explores factors and techniques associated with reduced rates of complications as well as the management of complications.

Traumatic temporomandibular joint bony ankylosis in growing rats

BACKGROUND

The pathogenesis of traumatic temporomandibular joint (TMJ) bony ankylosis remains unknown. This study aimed to explore the pathogenesis of traumatic TMJ bony ankylosis in a rat model.

METHODS

Twenty-four 3-week-old male Sprague-Dawley rats were used in this study. Excision of the whole disc, the fibrocartilage damage of the condyle and glenoid fossa, and narrowed joint space were performed in the left TMJ of the operation group to induce TMJ bony ankylosis (experimental side). The right TMJ underwent a sham operation (sham side). The control group did not undergo any operations. At 1, 4, and 8 weeks postoperatively, rats of the operation group were sacrificed and TMJ complexes were evaluated by gross observation, Micro-CT, histological examinations, and immunofluorescence microscopy. Total RNA of TMJ complexes in the operation group were analyzed using RNA-seq.

RESULTS

Gross observations revealed TMJ bony ankylosis on the experimental side. Micro-CT analysis demonstrated that compared to the sham side, the experimental side showed a larger volume of growth, and a considerable calcified bone callus formation in the narrowed joint space and on the rougher articular surfaces. Histological examinations indicated that endochondral ossification was observed on the experimental side, but not on the sham side. RNA-seq analysis and immunofluorescence revealed that Matrix metallopeptidase 13 (MMP13) and Runt-related transcription factor 2 (RUNX2) genes of endochondral ossification were significantly more downregulated on the experimental side than on the sham side. The primary pathways related to endochondral ossification were Parathyroid hormone synthesis, secretion and action, Relaxin signaling pathway, and IL-17 signaling pathway.

CONCLUSIONS

The present study provided an innovative and reliable rat model of TMJ bony ankylosis by compound trauma and narrowed joint space. Furthermore, we demonstrated the downregulation of MMP13 and RUNX2 in the process of endochondral ossification in TMJ bony ankylosis.

A Comparative Study on Sedation Efficacy Between General and Regional Anesthesia with Dexmedetomidine in Patients Under Maxillofacial Surgery

BACKGROUND AND OBJECTIVE

Securing the airway in the surgery of maxillofacial disorders and traumas is fundamental during the operation. The present study aims to investigate the beneficial sedative effects of dexmedetomidine (DEX) in patients who underwent maxillofacial surgery with regional anesthesia compared to general anesthesia.

METHODS

Fifty patients, aged 20-45 years old were randomly divided into two groups of regional anesthesia (RA) and general anesthesia (GA) (each n=25). The group RA received regional block with sedation (DEX: 1 μg/kg infused over 10 min followed by the maintenance dose of 0.5 μg/kg/h) and the group GA underwent general anesthesia (DEX: 0.1 μg/kg/min over 10 min followed by 0.4-0.7 μg/kg/h). Postoperative pain scores, anesthesia outcomes, hemodynamic parameters, the time of the post-anesthesia care unit (PACU) discharge and intra and postoperative complications were comparatively assessed in both groups.

RESULTS

The baseline characteristics of the patients (age, gender, BMI, and ASA physical status) showed no differences between the two groups (P>0.05). Although the duration of surgery and recovery time showed no differences between the groups, the duration of anesthesia and extubation time was remarkably lower in the RA group than in the GA group (P<0.01). Administration of nerve blocks demonstrated less pain and longer sleep time in the postoperative phase as compared to the GA group. Heart rate and mean arterial blood pressure were significantly less in the RA group at the end of the loading dose of DEX and incision time (P<0.05). SpO2, respiration rate and Ramsay sedation scale did not exhibit any significant differences between the two groups at all-time points (P>0.05). No significant differences were observed with regard to the adverse events between the two groups (P>0.05).

CONCLUSIONS

Although our findings revealed that both methods are suitable and safe methods for maxillofacial surgery, the outcomes of anesthesia with regional block and sedation include less pain in the postoperative phase, shorter extubation time and earlier discharge from the PACU demonstrated that this method is more reliable for maxillofacial surgery. Further controlled studies are needed to compare the effectiveness and safety profiles of two RA and GA techniques and also to compare DEX with other anesthetic agents to achieve optimum outcomes in maxillofacial surgeries.

Puricelli biconvex arthroplasty as an alternative for temporomandibular joint reconstruction: description of the technique and long-term case report

Background

There are several indications for partial or total replacement of the temporomandibular joint (TMJ), including neoplasms and severe bone resorptions. In this regard, several techniques have been suggested to increase the functionality and longevity of these prosthetic devices. This case report describes the treatment of a TMJ ankylosis patient with the Puricelli biconvex arthroplasty (ABiP) technique, with a long-term follow-up.

Case presentation

In 1978, a 33-year-old male polytraumatised patient developed painful symptoms in the right preauricular region, associated with restricted movement of the ipsilateral TMJ. Due to subcondylar fracture, an elastic maxillomandibular immobilisation (EMMI) was applied. Subsequently, the patient was referred for treatment when limitations of the interincisal opening (10 mm) and the presence of spontaneous pain that increased on palpation were confirmed. Imaging exams confirmed the fracture, with anteromedial displacement and bony ankylosis of the joint. Exeresis of the compromised tissues and their replacement through ABiP was indicated. The method uses conservative access (i.e., preauricular incision), partial resection of the ankylosed mass, and tissue replacement using two poly(methyl methacrylate) components, with minimal and stable contact between the convex surfaces. At the end of the procedure, joint stability and dental occlusion were tested. The patient showed significant improvement at the postoperative 6-month follow-up, with no pain and increased mouth opening range (30 mm). At the 43-year follow-up, no joint noises, pain or movement restrictions were reported (mouth opening of 36 mm). Imaging exams did not indicate tissue degeneration and showed the integrity of prosthetic components.

Conclusions

The present case report indicates that ABiP enables joint movements of the TMJ, allowing the remission of signs and symptoms over more than 40 years of follow-up. These data suggest that this technique is a simple and effective alternative when there is an indication for TMJ reconstruction in adult patients with ankylosis.

Contemporary perspectives on heterotopic ossification

Heterotopic ossification (HO) is the formation of ectopic bone that is primarily genetically driven (fibrodysplasia ossificans progressiva [FOP]) or acquired in the setting of trauma (tHO). HO has undergone intense investigation, especially over the last 50 years, as awareness has increased around improving clinical technologies and incidence, such as with ongoing wartime conflicts. Current treatments for tHO and FOP remain prophylactic and include NSAIDs and glucocorticoids, respectively, whereas other proposed therapeutic modalities exhibit prohibitive risk profiles. Contemporary studies have elucidated mechanisms behind tHO and FOP and have described new distinct niches independent of inflammation that regulate ectopic bone formation. These investigations have propagated a paradigm shift in the approach to treatment and management of a historically difficult surgical problem, with ongoing clinical trials and promising new targets.

Absorbance or organization into ankylosis: a microarray analysis of haemarthrosis in a sheep model of temporomandibular joint trauma

Background

Traumatic haemarthrosis was hypothesized to be the etiology of temporomandibular (TMJ) ankylosis. Here, taking haematoma absorbance as a control, we aimed to reveal the molecular mechanisms involved in haematoma organizing into ankylosis using transcriptome microarray profiles.

Material/methods

Disk removal was performed to building haematoma absorbance (HA) in one side of TMJ, while removal of disk and articular fibrous layers was performed to induced TMJ ankylosis through haematoma organization (HO) in the contralateral side in a sheep model. Haematoma tissues harvested at days 1, 4 and 7 postoperatively were examined by histology, and analyzed by Affymetrix OviGene-1_0-ST microarrays. The DAVID were recruited to perform the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis for the different expression genes (DEGs). The DEGs were also typed into protein–protein interaction (PPI) networks to get the interaction data. Six significant genes screened from PPI analysis, were confirmed by real-time PCR.

Results

We found 268, 223 and 17 DEGs at least twofold at days 1, 4 and 7, respectively. At day 1, genes promoting collagen ossification (POSTN, BGN, LUM, SPARC), cell proliferation (TGF-β), and osteogenic differentiation of mesenchymal stem cells (BMP-2) were up-regulated in the HO side. At day 4, several genes involved in angiogenesis (KDR, FIT1, TEK) shower higher expression in the HO side. While HA was characterized by a continuous immune and inflammatory reaction.

Conclusions

Our results provide a comprehensive understanding of the role of haematoma in the onset and progress of TMJ ankylosis. The study will contribute to explaining why few injured TMJs ankylose and most do not from the molecular level.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-021-02033-w.

Differences in the biological properties of mesenchymal stromal cells from traumatic temporomandibular joint fibrous and bony ankylosis: a comparative study

The aim of this study was to compare the functional characteristics of mesenchymal stromal cells (MSCs) from a sheep model of traumatic temporomandibular joint (TMJ) fibrous and bony ankylosis. A sheep model of bilateral TMJ trauma-induced fibrous ankylosis on one side and bony ankylosis on the contralateral side was used. MSCs from fibrous ankylosed callus (FA-MSCs) or bony ankylosed callus (BA-MSCs) at weeks 1, 2, 4, and 8 after surgery were isolated and cultured. MSCs derived from the bone marrow of the mandibular condyle (BM-MSCs) were used as controls. The MSCs from the different sources were characterized morphologically, phenotypically, and functionally. Adherence and trilineage differentiation potential were presented in the ovine MSCs. These cell populations highly positively expressed MSC-associated specific markers, namely CD29, CD44, and CD166, but lacked CD31 and CD45 expressions. The BA-MSCs had higher clonogenic and proliferative potentials than the FA-MSCs. The BA-MSCs also showed higher osteogenic and chondrogenic potentials, but lower adipogenic capacity than the FA-MSCs. In addition, the BA-MSCs demonstrated higher chondrogenic, but lower osteogenic capacity than the BM-MSCs. Our study suggests that inhibition of the osteogenic and chondrogenic differentiations of MSCs might be a promising strategy for preventing bony ankylosis in the future.

Mutations in the osteoprotegerin-encoding gene are associated with temporomandibular joint ankylosis

OBJECTIVE

This study aimed to investigate genetic variations in the osteoprotegerin-encoding gene (TNFRSF11B) in patients with temporomandibular joint ankylosis (TMJA).

STUDY DESIGN

The sample comprised 17 patients diagnosed with TMJA, of both sexes with ages ranging from 6 to 57 years old. TNFRSF11B mutational analysis was performed using the Sanger sequencing method with DNA extracted from oral cells, and the functional impact prediction of the variants was assessed using bioinformatic analysis.

RESULTS

Sequencing analysis identified 15 (88.23%) patients that presented at least 1 genetic variant in TNFRSF11B. The mutation rs202090603 (p.E33K) was found in 6 individuals, and rs140782326 (p.V281M), rs11573942 (p.L295), and rs1375250340 (p.I389T) were identified in 1 subject each. According to the pathogenicity potential of mutations, 3 variants were considered of low impact (rs2073618, rs202090603, and rs2228568) and 3 as disease causing (rs140782326, rs11573942, and rs1375250340). The variant rs202090603 (p.E33K) was found in the first cysteine domain with differences in the loop positions of p.E33K mutated the 3D structure of osteoprotegerin.

CONCLUSION

Two polymorphisms (rs2073618 and rs2228568) and the mutations rs202090603 (p.E33K), rs140782326 (p.V281M), rs11573942 (p.L295), and rs1375250340 (p.I389T) in the TNFRSF11B gene may be associated with TMJA.

Microarray Analysis of Differential Gene Expression Between Traumatic Temporomandibular Joint Fibrous and Bony Ankylosis in a Sheep Model

Background

The type of traumatic temporomandibular joint (TMJ) ankylosis depends on the degree of severity of TMJ trauma. Here, we performed comprehensive differential molecular profiling between TMJ fibrous and bony ankylosis.

Material/Methods

Six sheep were used and a bilateral different degree of TMJ trauma was performed to induce fibrous ankylosis in one side and bony ankylosis in the other side. The ankylosed calluses were harvested at days 14 and 28 postoperatively and analyzed by Affymetrix OviGene-1_0-ST microarrays. DAVID was used to perform the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis for the different expression genes (DEGs). The DEGs were also typed into protein–protein interaction (PPI) networks to get the interaction data. Ten DEGs, including 7 hub genes from PPI analysis, were confirmed by real-time PCR.

Results

We found 90 and 323 DEGs at least 2-fold at days 14 and 28, respectively. At day 14, bony ankylosis showed upregulated DEGs, such as TLR8, SYK, NFKBIA, PTPRC, CD86, ITGAM, and ITGAL, indicating a stronger immune and inflammatory response and cell adhesion, while genes associated with anti-adhesion (PRG4) and inhibition of osteoblast differentiation (SFRP1) had higher expression in fibrous ankylosis. At day 28, bony ankylosis showed increased biological process related to new bone formation, while fibrous ankylosis was characterized by a prolonged immune and inflammatory reaction.

Conclusions

This study provides a differential gene expression profile between TMJ fibrous and bony ankylosis. Further study of these key genes may provide new ideas for future treatment of TMJ bony ankylosis.

Comparison of unilateral rostral, middle and caudal segmental mandibulectomies as an alternative treatment for unilateral temporomandibular joint ankylosis in cats: an ex vivo study

OBJECTIVES

Temporomandibular joint ankylosis (TMJA) is the partial or complete inability to open the mouth due to intra- or extra-articular fibrous, bony or fibro-osseous tissue proliferation. Surgical procedures such as gap arthroplasty, condylectomy or wide extra-articular osteotomy have been recommended to treat this condition; these techniques are challenging, time-consuming and have been occasionally associated with postoperative recurrence, severe periarticular neurovascular iatrogenic trauma and death. Segmental mandibulectomy had previously been recommended as an alternative option for unilateral TMJA, but the location of mandibulectomy and extent of bone removal from the mandible region have not been mentioned in the literature. This study aimed to validate the area of the mandibular body (rostral, middle or caudal) and amount of bony tissue that should be osteotomized during a segmental mandibulectomy for treatment of unilateral TMJA in cats.

METHODS

In this block study, 30 cadaver heads of domestic shorthair cats were randomly divided into three groups of 10 specimens each based on the mandibular region that would undergo segmental mandibulectomy (rostral, middle and caudal). The size of the removed mandibular segment and pre- and postoperative vertical range of mandibular motion were compared for statistical purposes.

RESULTS

A significant statistical difference was observed between the pre- and postoperative vertical range of mandibular motion between the rostral, middle and caudal segmental mandibulectomies (P <0.001). The mean postoperative recovered range of mandibular motion for the rostral, middle and caudal segmental mandibulectomies was 50.4%, 81.9% and 90.4%, respectively.

CONCLUSIONS AND RELEVANCE

The caudal segmental mandibulectomy showed the highest postoperative vertical range of mandibular motion. The removal of a minimum of 1.2 cm of the caudal mandibular body was required to achieve nearly full recovery of presurgical mouth opening in the specimens of this study. The caudal segmental mandibulectomy may eliminate the risk of iatrogenic periarticular neurovascular damage inherent to more invasive surgeries performed at the temporomandibular joint area. When performed unilaterally, the caudal segmental mandibulectomy is a viable surgical alternative that may show a similar outcome to other surgical techniques.

Three-dimensional morphological analysis of neocondyle bone growth after fibula free flap reconstruction

The aim of this retrospective study was to verify the three-dimensional morphological change in neocondyle bone growth after fibula free flap (FFF) reconstruction. The independent variables were age, sex, and diagnosis. Outcome variables included the direction and volume of neocondyle bone growth, and the time to a stable neocondyle following bone growth. The outcome variables were measured on postoperative computed tomography scans using iPlan 3.0. Of the 35 patients included, 25 showed neocondyle bone growth. The direction of neocondyle bone growth included the direction of lateral pterygoid traction (DLPT) and the direction towards the glenoid fossa (DGF). The bone growth of the neocondyle showed three patterns: only DLPT (eight patients), only DGF (two patients), and a combination of DLPT and DGF (15 patients). The average volume of bone growth in the 25 patients was 0.479 ± 0.380 cm³. The average volume of neocondyle bone growth was significantly greater in patients aged <18 years (0.746 ± 0.346 cm³) than in patients aged >18 years (0.219 ± 0.191 cm³) (P < 0.001). The time to a stable neocondyle following bone growth was 5.6 months postoperatively. In conclusion, neocondyle bone growth after FFF reconstruction occurred in two different directions, DLPT and DGF. Osteogenesis of the lateral pterygoid muscle affects neocondyle growth with DLPT. Neocondyle bone growth is more marked in paediatric patients than in adults.

Dysregulated healing response participates in the pathophysiology of temporomandibular joint ankylosis

This study aimed to characterize samples from patients diagnosed with TMJ ankylosis, using both clinical and histological data. Both clinical and histological analyses of retrieved tissue samples from patients with primary TMJ ankyloses were performed retrospectively (1980-2012). All patients had been subjected to primary arthroplasty. Our study analyzed connective tissue differentiation, ossification patterns, and bone resorption, using histology and immunohistochemistry. Fifteen case records, with a sex ratio of 4:1 (men:woman) and a median age of 8 years, were collected. Six patient samples reported a previous inflammatory event. Histologically, 15 samples exhibited fibrous tissue. Among these, 13 displayed bone at different stages of maturity (fibrous/bony ankylosis). Eleven samples showed aberrant cartilage, characterized by hypertrophic chondrocyte-like cells at the bone/cartilage interface. Four samples revealed inflammatory infiltrate; in one case, this was organized as a lymphoid follicle. Eleven samples showed bone resorption by attached osteoclasts. Interestingly, non-attached osteoclasts were detected, suggesting locally impaired bone remodeling. An association between the presence of mature/lamellar bone and the presence of osteoclasts was observed (p = 0.03). No association was found between previous history of either trauma or infection and the histological type of ankylosis (p = 0.74). There was no association between the histological presence of inflammation or infection and the type of ankylosis (p = 0.63 and p = 0.87, respectively). Retrieved TMJ ankylosis tissues displayed both aberrant ossification and reduced focal bone resorption, suggesting a dysregulated healing response.

Temporomandibular Joint Ankylosis among Patients at Saint Paul's Hospital Millennium Medical College, Ethiopia: A 9-Year Retrospective Study

Background

Temporomandibular joint ankylosis (TMJA) is a gradually developing pathological condition manifested by a limited mouth opening. It can result in an extremely disabling deformity that may affect mastication, swallowing, speech, oral hygiene, and facial cosmetic appearance. The present study aimed to determine the pattern of TMJA at St. Paul's Hospital millennium medical college (SPHMMC), Addis Ababa, Ethiopia.

Methods

A retrospective descriptive study design was conducted at SPHMMC. All medical records of patients with the diagnosis of TMJA that visited the Maxillofacial Surgery unit from September 2010 through August 2019 were reviewed. Sociodemographic and clinical data including age, sex, place of residency, duration of TMJA cases, etiology, clinical presentations, imaging results, type of surgical operation, and complications after surgery were collected and analyzed using IBM SPSS software version 20 for Windows (Armonk, NY, USA: IBM Corp) computer program.

Results

A total of 130 patients' medical records were reviewed. Out of this, 95 were included in the study. Forty-two (44.2%) of the TMJA cases were males, while the remaining 53 (55.8%) were females with a male to female ratio of 0.79 : 1. 20-29-year-old patients were the most affected, 36 (37.9%), followed by the 30 to 39 years age group, 33 (34.7%). Trauma (77.9%) was identified as the most common cause of TMJA. Notably, bilateral ankylosis (72.6%) was more common than unilateral (27.3%), and micrognathia was the most common (23.0%) deformity observed. The majority 52 (54.7%) of TMJA patients were treated with gap arthroplasty.

Conclusions

TMJA was predominant among females than their male counterparts. Of note, 20-29-year-old patients were the most affected group. The majority of TMJA cases were treated by gap arthroplasty with almost no postoperative complications. Early detection and intervention to release the ankylosed joint is needed to improve patients' quality of life.

Lateral pterygoid muscle enthesis reconstruction in total temporomandibular joint replacement: An animal experiment with radiological correlation

A novel total temporomandibular joint replacement (TMJR) was developed with CADskills BV (Ghent, Belgium), aiming to achieve reinsertion of the (LPM) onto a scaffold in the implant. In order to investigate the possibility of reinsertion of the LPM, an animal experiment was conducted. An in vivo sheep experiment was conducted, which involved implanting sheep with a TMJR. Clinical parameters were recorded regularly and computed tomography (CT) scan images of two randomly selected sheep per scan were made at 1, 3, and 6 months. After 9.5 months, the sheep were euthanized, and CT scans of all animals were performed in order to evaluate the LPM's enthesis. A total of 13 sheep were implanted with a TMJR. One sheep was used as a sham. Radiographs revealed four outcome types of enthesis reconstruction. In four sheep, there was no reconstruction between the implant and the LPM. In three sheep, there was a purely soft tissue connection of 0.5-0.9 mm (average 0.7 mm) between the ostectomized bony LPM insertion and the implant's lattice structure. A combination of partial bony and partial soft tissue enthesis attachment (0.3-0.5 mm, average 0.4 mm) was found in three sheep. A bony ingrowth of the enthesis into the scaffold occurred in two sheep. A secondary bony connection between the mandible and the insertion of the LPM was found in 10 of 13 sheep. Four fossa components were found to be displaced, yet TMJ function remained in these ewes. The heterotopic ossification that was seen may be a confounding factor in these results. This in vivo experiment showed promising results for improving the current approach to TMJR with the possibility of restoring the laterotrusive function. The fossa displacement was considered to be due to insufficient fixation and predominant laterotrusive force not allowing for proper osseointegration. Further optimization of the reattachment technique, scaffold position and surface area should be done, as well as trials in humans to evaluate the effect of proper revalidation.

Pathogenesis of traumatic temporomandibular joint ankylosis: a narrative review

OBJECTIVE

To comprehensively review the literature and summarize the results from human and animal studies related to the possible causes and pathogenesis of traumatic temporomandibular joint ankylosis (TMJA).

MATERIALS AND METHODS

The Google Scholar, Embase, and Web of Science databases were used to search for articles related to traumatic TMJA from 2011 to 2020. All articles were screened according to the inclusion and exclusion criteria, collected, and analyzed.

RESULTS

Nineteen relevant articles were collected. These articles were classified into three groups: predisposing and etiological factors, cellular studies, and molecular studies.

CONCLUSION

The pathological mechanisms are similar between TMJA and nonunion hypertrophy. Aberrant structural and etiological factors as well as disordered cellular and molecular mechanisms might contribute to TMJA formation. Although preclinical and clinical data have provided new evidence on the pathogenesis of traumatic TMJA, the molecular mechanisms and biological events require further exploration.

Efficacy of temporomandibular joint arthroplasty and insertion of a Matthews device as treatment for ankylosis of the joint: a case series

Temporomandibular joint (TMJ) ankylosis is a condition in which bony or fibrous adhesion of the anatomical joint components results in loss of function. This is particularly distressing and debilitating for patients who struggle to maintain good oral hygiene, which results in additional pain, oral disease, and ultimately, a poor aesthetic profile. A retrospective chart review was carried out to document the cases of three patients who attended a single centre for the management of ankylosis of the TMJ. Consent for chart review and use of photographs was gained from each one. Charts were obtained, records reviewed, and each of the cases written up for presentation in a case series. All three underwent arthroplasty of the TMJ and insertion of Matthews devices (two patients unilateral, one bilateral). All were followed up postoperatively. They experienced significant improvements in vertical mouth opening which have been maintained to the present. The Matthews device allows movement and physiotherapy postoperatively whilst maintaining the surgically created space. This prevents impingement on the tissues placed between the glenoid fossa and mandible, and appears to prevent relapse and further ankylosis. To our knowledge, few studies to date have documented the use of the Matthews device following interpositional arthroplasty of the TMJ.

Stimulating Factors and Origins of Precursor Cells in Traumatic Heterotopic Ossification Around the Temporomandibular Joint in Mice

The contributing factors and the origins of precursor cells in traumatic heterotopic ossification around the temporomandibular joint (THO-TMJ), which causes obvious restriction of mouth opening and maxillofacial malformation, remain unclear. In this study, our findings demonstrated that injured chondrocytes in the condylar cartilage, but not osteoblasts in the injured subchondral bone, played definite roles in the development of THO-TMJ in mice. Injured condylar chondrocytes without articular disc reserves might secrete growth factors, such as IGF1 and TGFβ2, that stimulate precursor cells, such as endothelial cells and muscle-derived cells, to differentiate into chondrocytes or osteoblasts and induce THO-TMJ. Preserved articular discs can alleviate the pressure on the injured cartilage and inhibit the development of THO-TMJ by inhibiting the secretion of these growth factors from injured chondrocytes. However, the exact molecular relationships among trauma, the injured condylar cartilage, growth factors such as TGFβ2, and pressure need to be explored in detail in the future.

Intra- and Extra-articular Features of Temporomandibular Joint Ankylosis in the Cat (Felis catus)

Temporomandibular joint (TMJ) ankylosis is an uncommon clinical entity in human and veterinary medicine. However, the condition is severely debilitating and is life-limiting if not treated. This study sought to characterize the intra- and extra-articular features of naturally occurring TMJ ankylosis in cats. TMJs from client-owned cats (n = 5) that underwent bilateral TMJ gap arthroplasty were examined and compared with TMJs from healthy, age-matched feline cadavers (n = 2) by cone-beam computed tomography (CBCT), micro-computed tomography (μCT) and histologically. Features of bilateral intra- and extra-articular ankylosis compounded by degenerative joint lesions were identified radiographically and histologically in all affected cats. Features of TMJ 'true' ankylosis included variable intracapsular fibro-osseous bridging, degeneration of the disc and the articular surfaces, narrowing of the joint space and flattening of the condylar process of the mandible. Extra-articular features of TMJ ankylosis included periarticular bone formation and fibro-osseous bridging between the mandible, zygomatic arch and coronoid process. In addition, subchondral bone loss or sclerosis, irregular and altered joint contours and irregularly increased density of the medullary bone characterized the degenerative changes of the osseous components of the TMJ. Complex radiological and histological features of both ankylosis and pseudoankylosis were identified that clinically manifested in complete inability to open the mouth.

Which of the fibrous layer is more important in the genesis of traumatic temporomanibular joint ankylosis: The mandibular condyle or the glenoid fossa?

INTRODUCTION

The aim of this experimental study was to investigate, under the premise of discectomy, whether damage to either the fibrous layer of the condyle or that of the glenoid fossa, could induce temporomanibular joint (TMJ) ankylosis. And if not, which of the fibrous layer was more important in the genesis of TMJ ankylosis.

MATERIALS AND METHODS

Bilateral TMJ surgery was performed in 6 growing Xiao-wei Han sheep. Disk and condylar fibrous layer removal (DCFLR) was performed on the left TMJ, and disk and glenoid fibrous layer removal (DGFLR) was performed on the right TMJ. All animals were sacrificed at 3 months postoperatively. The TMJ complexes were examined by histological evaluation.

RESULTS

Partial fibrous ankylosis was achieved on the DCFLR side in the 6 sheep at 3 months after surgery. On the DGFLR side, pathologic characteristics of TMJ osteoarthritis could be seen; however, no evidence of ankylosis was observed. The scores of TMJ ankylosis for the DGFLR side were significantly lower than those for the DCFLR side (P<0.05).

CONCLUSION

This study demonstrated that removal of the condylar fibrous layer, not the glenoid fibrous layer, combined with discectomy could lead to traumatic TMJ ankylosis.

Reducing macrophage numbers alleviates temporomandibular joint ankylosis

Temporomandibular joint (TMJ) ankylosis is a severe joint disease mainly caused by trauma that leads to a series of oral and maxillofacial function disorders and psychological problems. Our series of studies indicate that TMJ ankylosis development is similar to fracture healing and that severe trauma results in bony ankylosis instead of fibrous ankylosis. Macrophages are early infiltrating inflammatory cells in fracture and play a critical role in initiating fracture repair. We hypothesize that the large numbers of macrophages in the early phase of TMJ ankylosis trigger ankylosed bone mass formation and that the depletion of these macrophages in the early phase could inhibit the development of TMJ ankylosis. By analysing human TMJ ankylosis specimens, we found large numbers of infiltrated macrophages in the less-than-1-year ankylosis samples. A rabbit model of TMJ bony ankylosis was established and large numbers of infiltrated macrophages were found at 4 days post-operation. Local clodronate liposome (CLD-lip) injection, which depleted macrophages, alleviated the severity of ankylosis compared with local phosphate-buffered saline (PBS)-loaded liposome (PBS-lip) injection (macrophage number, PBS-lips vs. CLD-lips: 626.03 ± 164.53 vs. 341.4 ± 108.88 n/mm²; ankylosis calcification score, PBS-lips vs. CLD-lips: 2.11 ± 0.78 vs. 0.78 ± 0.66). Histological results showed that the cartilage area was reduced in the CLD-lip-treated side (PBS-lips vs. CLD-lips: 6.82 ± 4.42% vs. 2.71 ± 2.78%) and that the Wnt signalling regulating cartilage formation was disrupted (Wnt5a expression decreased 60% and Wnt4 expression decreased 73%). Thus, our study showed that large numbers of macrophages infiltrated during the early phase of ankylosis and that reducing macrophage numbers alleviated ankylosis development by reducing cartilage formation.

Differential regulation of blood vessel formation between traumatic temporomandibular joint fibrous ankylosis and bony ankylosis in a sheep model

OBJECTIVES

Clinical and experimental studies show that the etiology of traumatic temporomandibular joint (TMJ) fibrous ankylosis and bony ankylosis are associated with the severity of trauma. However, how the injury severity affects the tissue differentiation is not clear. We tested the hypothesis that angiogenesis affects the outcomes of TMJ trauma, and that enhanced neovascularization after severe TMJ trauma would promote the development of bony ankylosis.

METHODS

Bilateral condylar sagittal fracture and discectomy were performed for each sheep, with the glenoid fossa receiving either severe trauma to induce bony ankylosis or minor trauma to induce fibrous ankylosis. At days 7, 14, 28, and 56 after surgery, total RNA was extracted from the ankylosed callus. Temporal gene expressions of several molecules functionally important for blood vessel formation were studied by real-time PCR.

RESULTS

Histological examination revealed a prolonged hematoma phase and a lack of cartilage formation in fibrous ankylosis. mRNA expression levels of HIF-1α, VEGF, VEGFR2, SDF1, Ang1, Tie2, vWF, CYR61, FGF2, TIMP1, MMP2, and MMP9 were distinctly lower in fibrous ankylosis compared with bony ankylosis at several time points.

CONCLUSIONS

Our study indicates that inhibition of angiogenesis after TMJ trauma might be a promising strategy for preventing bony ankylosis in the future.

Association between the clinical features of and types of temporomandibular joint ankylosis based on a modified classification system

This study aimed to describe the clinical features of different types of traumatic temporomandibular joint (TMJ) ankylosis. Seventy-one patients with 102 ankylosed joints were retrospectively reviewed and categorized into four groups according to the grades of severity: type I, non-bony ankylosis of the joint with almost-normal joint space; type II, lateral bony ankylosis marked by a normal joint space that coexists with a radiolucent line; type III, complete bony ankylosis of the joint characterized by only a radiolucent line; and type IV, extensive bony ankylosis without any radiolucent line. The period of ankylosis, maximal mouth opening (MMO), rate of complications, and histopathological changes were compared among groups. Intergroup comparison showed significant differences in the clinical features of MMO and the incidence of complications (p < 0.05). Younger trauma patients tended to develop more severe types of ankylosis than older patients. Additionally, long post-trauma periods were related to the development of severe ankylosis. MMO was highly negatively correlated with the severity of ankylosis. Significant differences were noted among the four types of ankylosis. Younger trauma patients with long post-trauma periods tended to develop more severe TMJ ankylosis, experience more complications, and face more challenges in treatment than older patients.

Removal of the articular fibrous layers with discectomy leads to temporomandibular joint ankylosis

OBJECTIVE

The aim of this study was to investigate whether direct damage of the articular fibrous layers without condylar fracture, combined with discectomy, was enough to induce temporomandibular joint (TMJ) ankylosis.

STUDY DESIGN

Bilateral TMJ surgery was performed in 8 growing sheep. Disk removal (DR) was performed in the lateral two-thirds on the control side, and disk and articular fibrous layers removal (DFLR) was performed in the lateral two-thirds on the experimental side. Four animals were sacrificed for each side at 1 and 3 months postoperatively.

RESULTS

Fibrous ankylosis was achieved on the DFLR side in 2 of 4 sheep and fibro-osseous ankylosis in the other 2 sheep at 1 month after surgery. Fibro-osseous ankylosis developed on the DFLR side in 4 sheep at 3 months postoperatively. On the DR side, pathologic characteristics of TMJ osteoarthritis could be seen; however, no evidence of ankylosis was observed. The scores of TMJ ankylosis for the DR side were significantly lower than those for the DFLR side at different time points (P < .05).

CONCLUSIONS

This study demonstrated that removal of articular fibrous layers combined with discectomy can lead to traumatic TMJ ankylosis.

Preserving the Fibrous Layer of the Mandibular Condyle Reduces the Risk of Ankylosis in a Sheep Model of Intracapsular Condylar Fracture

PURPOSE

The aim of this experimental study was to investigate the role of the fibrous layer of the condylar head in the formation of temporomandibular joint (TMJ) ankylosis in a sheep model of intracapsular condylar fracture.

MATERIALS AND METHODS

Six growing Xiao-wei Han sheep were used in the study, and bilateral TMJ surgery was performed in each sheep. In the left TMJ, sagittal fracture of the condyle, removal of the fibrous layer of the condylar head, excision of two thirds of the disc, and removal of the fibrous zone of the glenoid fossa were performed. In the right TMJ, the same surgical management was performed, except that in each sheep, the fibrous layer of the condylar head was preserved. Three sheep were killed humanely at 1 month postoperatively, and the other 3 sheep were killed humanely at 3 months postoperatively. The TMJ complexes were examined by histologic evaluation.

RESULTS

Fibrous ankylosis was observed on the left side in 3 sheep at 1 month postoperatively and in 2 of 3 sheep at 3 months postoperatively. Fibro-osseous ankylosis was achieved on the left side in 1 sheep at 3 months postoperatively. In the right TMJ, the main postoperative histologic findings included condylar fracture healing, topical rupture or exfoliation of the fibrous layer of the condyle, and fissure between the fibrous layer and the proliferative zone of the condyle. However, no evidence of ankylosis was observed. The TMJ ankylosis scores on the right side were significantly lower than those on the left side at different time points (P < .05).

CONCLUSIONS

This study showed that the presence of the fibrous layer of the condylar head prevented the development of TMJ ankylosis in a sheep model of intracapsular condylar fracture.

Current thinking about the management of dysfunction of the temporomandibular joint: a review

Increasingly the management of TMJ pathology is becoming a subspecialist interest. The number of patients having TMJ joint replacement had steadily increased over the last decade and there is now NICE guidance on this matter. Whilst the evidence of the management of TMJ disease is limited and there are few randomised controlled trials, the incidence of TMJ pathology has not changed and there is a requirement for guidance on the management. Whilst previously patients with TMJ pain were managed surgically, this is changing, and the vast bulk of initial management is non-surgical/medical. This paper will review the literature on TMD and provide guidance for management.

Temporomandibular joint ankylosis after condylar dislocation into the middle cranial fossa: A case report

INTRODUCTION

Dislocation of the mandibular condyle into the middle cranial fossa after a trauma is a rare event. The lack of appropriate treatment can lead to ankylosis of the temporomandibular joint (TMJ). We report about a case of TMJ ankylosis following intracranial dislocation of the mandibular condyle through the roof of the articular fossa.

CASE REPORT

A 9-year-old patient was referred for a severe limitation of mouth opening that began progressively one year before. A history of chin injury due to an accidental fall was found. Preoperative CT scan showed a TMJ ankylosis on the right side combined with a dislocation of the mandibular condyle into the middle cranial fossa. Treatment consisted in an intracranial resection of the mandibular condyle, partial removal of the ankylosis block and TMJ arthroplasty.

DISCUSSION

Our case is the second case of TMJ ankylosis following intracranial dislocation of the mandibular condyle and treated with arthroplasty alone published in the English literature. There is no consensus regarding the pathophysiology of TMJ ankylosis and regarding the attitude towards the ankylosis block. In our case, no recurrence was noticed after a one-year follow-up. An interdisciplinary approach is needed, including maxillofacial surgeon, neurosurgeon, physiotherapist and orthodontist.

Management of Young Patients with Temporomandibular Joint Ankylosis-a Surgical and Anesthetic Challenge

Temporomandibular joint ankylosis is a unique disease where fracture of the mandibular condyle or any other cause leading to ankylosis of the joint can lead to multiple problems if not detected and treated early. If affected in early years of life, it may cause facial dysmorphism, restricted mouth opening, and difficulty in eating, speech, and sleep. Early surgery and physiotherapy can restore the joint function to a great extent. Anesthetizing a pediatric patient with this disorder is a definite challenge which needs expertise in difficult airway management.

A comparative study of different surgical methods in the treatment of traumatic temporomandibular joint ankylosis

Two different surgical methods for the treatment of unilateral traumatic temporomandibular joint (TMJ) ankylosis with a medially displaced residual condyle are described. Eighteen patients with unilateral traumatic TMJ ankylosis and a medially displaced residual condyle, treated between 2008 and 2013, were included in this study. Group A patients (n=10) were treated with an autogenous coronoid process graft (ACPG) for reconstruction of the mandibular condyle, while group B patients (n=8) were treated by lateral arthroplasty (LAP); a temporalis myofascial flap (TMF) was used as interpositional material in both groups. The long-term results of the two treatments were compared through postoperative computed tomography and clinical follow-up examinations. The two groups were compared in terms of the recurrence rate, facial pattern change, and improvement in maximum inter-incisal opening (MIO) using SPSS 18.0 software. All patients were followed up for 12-24 months. Two patients in group A (20%) had reankylosis; no reankylosis was observed in group B patients. Compared with the ACPG, LAP improved the facial pattern and MIO significantly (P<0.05). LAP is a feasible and effective surgical method for the treatment of unilateral traumatic TMJ ankylosis when the displaced residual condyle is bigger than one third of the condylar head.

Influence of the lateral pterygoid muscle on traumatic temporomandibular joint bony ankylosis

BACKGROUND

The pathogenesis of traumatic TMJ ankylosis remains unclear. This study aimed to verify the role of the lateral pterygoid muscle in the pathogenesis of traumatic temporomandibular joint (TMJ) bony ankylosis.

METHODS

Eight 6-month-old male sheep were used in this study. Bilateral TMJ osteotomies were performed to induce sagittal fractures of the mandibular condyle. The lateral one-fourth segment of the disc was removed to establish a model of TMJ bony ankylosis. Subsequently, the function of the left and right lateral pterygoid muscles was blocked (experimental group) or maintained (control group), respectively. At 12 weeks postoperatively, animals were sacrificed and TMJ complex samples were evaluated by gross observation, spiral computed tomography (CT), micro-CT, and histological examinations.

RESULTS

Gross observation revealed bony ankylosis in the control TMJs and fibrous adhesions in the experimental TMJs. Spiral CT and micro-CT demonstrated that, compared to the experimental group, the control group showed calcified callus formation in the joint space and roughened articular surfaces after new bone formation, which protruded into the joint space. Maximum mediolateral and anteroposterior condylar diameters were significantly larger in the control group than in the experimental group. Micro-CT also showed that the primary growth orientation of new trabeculae was consistent with the direction of lateral pterygoid traction in the control group, but not in the experimental group. Histological examination showed fibro-osseous ankylosis in the control group, but not in the experimental group.

CONCLUSIONS

The lateral pterygoid simulates the effects of distraction osteogenesis, which is an important factor in the pathogenesis of TMJ bony ankylosis during the healing of sagittal condylar fractures.

A Case of Glenoid Fossa Fracture, Progressive Ankylosis, Total Joint Reconstruction with Alloplastic Prosthesis to Normalized Function Including Evaluation with F18-PET/CT-a Four Year Follow-up

Temporomandibular joint replacement (TJR) with alloplastic prosthesis has shown promising long-term results in end stage joint disorders. We present a case of young woman with painful ankylosis that where reconstructed with TJR, due to a complex mandibular fracture with dislocation of the left condyle into the middle cranial fossa two years earlier. At the age of 18 the subject underwent a total joint replacement with custom-made alloplastic TMJ prosthesis. To determine the bone response and remodeling activity around the prosthesis, a F18 PET/CT-scan was used. No sign of increased remodeling or pathology were seen in the imaging after the reconstruction. Four years postoperatively the subject reports no pain and excellent jaw function.