Temporomandibular Joint Anatomy Research Articles

Comparative evaulation of condylar guidance obtained by digital panoramic radiographic images with that of obtained during jaw relation and try-in using two different interocclusal record material in completely edentulous patients: an in vivo study

Background In completely edentulous patients, maintaining the patient’s temporomandibular joint (TMJ) health and intraoral components is very essential, which can be achieved by an accurate interocclusal record, which can be taken by various materials and also at various stages. Simulation of the temporomandibular joint anatomy and mandibular movements is possible on a semi-adjustable articulator, which is widely used in prosthodontics. Transferring the record on articulator is a critical step in the fabrication of complete dentures, so it should be done precisely to reduce chair side time and also to avoid complications for patients. This study examines which material is more accurate and records which stage gives more precision by comparing the Condylar guidance on radiographs. This is because it is a relatively consistent bony landmark and can be used to correlate with clinical methods in terms of verification. The objective is to determine the inter occlusal records created during the Jaw Relation stage and Try-in using reinforced wax and Polyvinyl siloxane and compare these values to the condylar guidance obtained by orthopantomogram (OPG). Methods Recording the Condylar Guidance value on OPG by tracing the Glenoid fossa, Articular eminence, and the Frankfurt Horizontal Plane. Followed by conventional steps in making complete dentures at jaw relation and try-in stage. We will record values of condylar guidance with the two different Interocclusal record materials. Expected result It will help the clinicians to gain knowledge about obtaining precise condylar inclination angle by using suitable interocclusal record materials. Conclusions This study will help us to obtain condylar inclination, which in turn helps the patient’s satisfaction as it preserves the intraoral components and health of TMJ.

Comparative evaulation of condylar guidance obtained by digital panoramic radiographic images with that of obtained during jaw relation and try-in using two different interocclusal record material in completely edentulous patients: an in vivo study

Background In completely edentulous patients, maintaining the patient's temporomandibular joint (TMJ) health and intraoral components is very important, which can be achieved by an accurate interocclusal record, which can we taken by various materials and also at various stages. Simulation of the temporomandibular joint anatomy and mandibular movements is possible on a semi-adjustable articulator, which is widely used in prosthodontics. Transferring the record on articulator is a critical step in the fabrication of complete dentures so it should be done precisely to reduce chair side time and also to avoid complications for patients. This study examines which material is more accurate and records which stage gives more precision, by comparing the Condylar guidance on radiographs. This is because it is a fairly consistent bony landmark and can be used for correlating with the clinical methods in terms of verification. The objective is to determine the inter occlusal records created during the Jaw Relation stage and Try-in using reinforced wax and Polyvinyl siloxane and compare these values to the condylar guidance obtained by oethopantomogram (OPG). Methods Recording the Condylar Guidance value on OPG by tracing the Glenoid fossa, Articular eminence and the Frankfurt Horizontal Plane. Followed by conventional steps in making complete dentures, at jaw relation and try-in stage. We will record values of condylar guidance with the two different Interocclusal record materials. Expected result It will help the clinicians to gain knowledge about obtaining precise condylar inclination angle by using suitable interocclusal record materials. Conclusions This study will help us to obtain condylar inclination which inturn helps the patients satisfaction as it preserves the intraoral components and health of TMJ.

Study of Prevalence of Temporomandibular Disorders among Undergraduate Students

Temporo-mandibular joint function has been extensively studied for more despite extensive investigation, the complicated etiology of TMJ dysfunction has remained a mystery for more than a century. Temporomandibular disorder (TMD) is a sub - class of painful orofacial conditions characterized by complaints of pain in the region of the temporomandibular joint (TMJ), difficulty concentrating craniocervicofacial muscles, especially mastication muscles, limitations of mandibular movement, and the presence of articular clicking. Emotional stress, occlusal interferences, tooth loss, postural deviation, muscles of mastication neuromuscular both internal and external dysfunction anomalies in Temporo-mandibular joint anatomy, and the multiple interrelationships between these factors all contribute to the complicated etiology of TMD.Aim: Determine the prevalence of temporomandibular joint disorder between college students. The sample for this sectional potential study consisted of 691 college students (339 male and 352 female). Self-reported questionnaires were used to determine the incidence and severity of TMJ disorders. By virtue of the quantity and frequency of notable replies, the rankings were upgraded to an intensity ranking. Results:56.6% of students reported some level of TMD, including 39.7% with mild TMD, 12.2% with moderate TMD, and 4.6% with severe TMD. Historically, no significant correlation between gender and TMD severity was observed.Conclusion: This student population exhibited a high prevalence of TMD; however, the majority of cases were mild. The statistical significance of the association between TMD severity and gender is no longer proven. Despite having TMD. The students had little knowledge of their conditions.

Anatomic Characteristics of Ultrasound Imaging of the Temporomandibular Joint at Rest and in Various Jaw Positions in Healthy Individuals: A Descriptive Study

This study examined the temporomandibular joint (TMJ) anatomy and biomechanics using Ultrasound (US) imaging to examine the TMJ anatomy at rest and in various positions of normal jaw movement in healthy individuals. A secondary aim was to describe US imaging parameters used to visually observed the TMJ. The study included 11 participants (8 M and 3 F; 22.9 ± 3.4 yrs) University with no history of TMJ problems. All 11 participants had some atypical anatomy (flat mandibular head, altered articular disc shape, displacement or deformation of the disc during movement) while using US imagining. No participants had current pain or dysfunction and none met the Diagnostic Criteria for Temporomandibular Dysfunction (DC-TMD) classifications for the condition. Most participants denied symptoms during testing, although one participant did have pain with retrusion and another had popping without pain. This study in part has added to the growing interest of using US imaging as modality to investigate the anatomy and biomechanics of the TMJ and the relationship to TMD. Future studies are warranted to examine TMJ anatomy and biomechanics via US imaging in order to provide further recommendations on the techniques and settings for the modality for the end-user.

A Plastic Surgeon’s Guide to the Temporomandibular Joint: Part I, Anatomy

The temporomandibular joint (TMJ) is a critical articulation between the mandible and cranium. The unique anatomy allows for a multifaceted motion unlike any other joint in the human body. The bi-convex curvature of the bony prominences facilitates a compound hinging and sliding movement, which are driven by the muscles of mastication and constrained by various ligamentous connections surrounding the joint. Proper alignment and function of these structures are essential to ensure a relationship between the mandibular and maxillary dental arches and fluid motion of the mandible during mastication. While the versatile form and function of the TMJ allow for coordinated jaw movements, pathologic conditions can lead to dysfunction and pain. Therefore, understanding the anatomy and associated pathophysiology of the TMJ is critical for a plastic surgeon who manages craniomaxillofacial trauma and disorders. The present manuscript is the first of a 3-part series with an overview of the TMJ anatomy. Subsequent sections will address the pathology and the treatment of various TMJ disorders.

Complicated Relationships between Anterior and Condylar Guidance and Their Clinical Implications-Comparison by Cone Beam Computed Tomography and Electronic Axiography-An Observational Cohort Cross-Sectional Study.

A complex prosthodontic treatment is believed to be more successful when the condylar path is replicated using the articulator. However, there is an ongoing major disagreement between the researchers as the exact relationship between the posterior and anterior determinants has not been clear. The purpose of this study was to investigate whether the protrusive movement of the mandible does correlate with the temporomandibular joint (TMJ) anatomy or with incised features. Subjects (15 males and 15 females) were qualified for this study based on an initial interview including the following criteria: age 21-23 (+/-1), no history of trauma, orthodontic treatment, or temporomandibular disorders (TMD). For each patient, the angle of the condylar path, incisal guidance angle (IGA), interincisal angle, as well as overbite and overjet were measured on cone beam computed tomography (CBCT). This was followed by the examination with the Modjaw® electronic axiograph recording and calculating the functional sagittal condylar guidance angle (SCGA) for the right and left TMJ during the protrusion. The results show that the mean functional axiographic measurement of SCGA in protrusion significantly correlates with the TMJ anatomy presented on CBCT. Moreover, a significant correlation was found between the values of SCGA in the functional and anatomical measurements in all its variants. It turned out that, statistically, the AB measurement was the most accurate. Finally, results showed that incisal relationships of permanent teeth such as overbite, overjet, incisal guidance angle and interincisal angle do not correlate with TMJ anatomy, and therefore, regarding an analyzed study group, do not affect the TMJ formation in young adults.

Temporomandibular joint anatomy, function and clinical relevance.

The articulatory system comprises the temporomandibular joints (TMJs), intra-articular discs, mandibular/jaw muscles and occlusion. In the simplest terms, the TMJ is the articulation between the upper and lower jaws. The teeth form the contacts between the upper and lower jaws and the muscles are the motors that move the mandible. This system is unique in that the TMJs are paired; any stimulus that affects one joint or any other single part of the articulatory system can have a 'knock-on effect' in the rest of the system.It is important to have a good understanding of anatomy, not only to be able to differentiate between what is physiological and what is pathological, but also to understand the objectives of some treatment options. Sound knowledge of anatomy is essential and an appreciation of the anatomical features associated with the TMJ can serve as a foundation for understanding the clinical management of temporomandibular disorders.This article reviews the functional anatomical features of the articulatory system with a look at the clinical significance of this anatomy.

Navigation in surgical arthroscopy of the temporomandibular joint

Surgical navigation is a technique that has evolved greatly in recent years. It allows surgeons to navigate through the surgical field in real time, and helps to locate anatomical structures or lesions and to place devices in complex anatomical regions with relatively high accuracy. In this article, we describe the application of surgical navigation in temporomandibular joint (TMJ) arthroscopy using an optical surgical navigator for a more precise diagnosis and to accurately place instruments in the desired position, especially in lateral pterygoid myotomy. We believe this technique will extend our understanding of the TMJ anatomy and will improve functional results in TMJ arthroscopy.

A rabbit model to investigate temporomandibular joint osteochondral regeneration

The objective of this study was 2-fold: (1) to describe the rabbit temporomandibular joint (TMJ) anatomy and (2) to provide a detailed, step-by-step description of a minimally invasive approach to perform a standard osteochondral TMJ defect that can be used to investigate the regenerative potential of biomaterials. This study was performed in 2 steps. In the first, a total of 8 rabbit carcasses (n=16 joints) were used to study the normal TMJ anatomy and histology to develop a minimally invasive approach to access the articulating surface of the condyle to perform a standard osteochondral defect. In the second, the surgical procedure was performed in 10 live animals to evaluate the feasibility of the model and to evaluate the regenerative potential of a biodegradable light-cured hydrogel seeded with stem cells (results not shown). The cartilage of the mandibular condyle showed 4 layers: fibrous, proliferative, hypertrophic, and a zone of calcified cartilage. Positive safranin O staining was observed in the cartilage. The mean duration of the procedure (from incision to last stitch) was 35.5 (±9.21) minutes. All animals survived the procedures without any major complications. This animal model represents an easy and nonmorbid surgical approach to rabbit TMJ.

Radiographic Assessment of the Feline Temporomandibular Joint with Oblique Projections: A Preliminary Ex Vivo Study.

Radiographic assessment of the temporomandibular joint in the domestic cat using conventional radiographic views can be challenging due to superimposition of overlying structures and the complex anatomy of the skull. The use of computed tomography, magnetic resonance imaging, and cone beam computed tomography to assess the temporomandibular joint in the cat has increased, but these modalities are not always available in general veterinary practices. Conventional radiography is still commonly used for first line assessment of the temporomandibular joint. The aim of this preliminary study was to determine optimal angle of obliquity of lateroventral-laterodorsal and laterorostral-laterocaudal (nose up lateral oblique) oblique radiographic views in the assessment of the temporomandibular joints in five feline mesaticephalic dry skulls. Visibility of the mandibular head, mandibular fossa, retroarticular process, and temporomandibular joint space were evaluated and scored by two veterinary radiologists. The results of this study identified that the dependent temporomandibular joint anatomy was best seen on the latero-10°-ventral-laterodorsal, latero-15°-ventral-laterodorsal, and latero-20°-ventral-laterodorsal, oblique views, and opposite lateral oblique views at these angulations may be helpful in characterization of this anatomy in clinical patients. The results also indicate that the laterorostral-laterocaudal (nose up lateral oblique) oblique view did not allow adequate discrimination of all TMJ anatomy at any angle, and is not recommended.

Structure-function relationships of TMJ lateral capsule-ligament complex

The human temporomandibular joint (TMJ) lateral capsule ligament (LCL) complex is debated as a fibrous capsule with distinct ligaments or ligamentous thickening, necessitating further evaluation of the complex and its role in TMJ anatomy and mechanics. This study explores the ultrastructural arrangement, biomechanical tensile properties, and biochemical composition of the human LCL complex including region-specific differences to explore the presence of a distinct temporomandibular ligament and sex-specific differences to inform evaluations of potential etiological mechanisms. LCL complex ultrastructural arrangement, biomechanical properties, and biochemical composition were determined using cadaveric samples. Statistical modeling assessed sex- and region-specific effects on LCL complex tissue properties. Collagen fiber coherency, collagen fiber bundle size, and elastin fiber count did not differ between sexes, but females trended higher in elastin fiber count. LCL complex water and sGAG content did not differ between sexes or regions, but collagen content was higher in the anterior region (311.0 ± 185.6 μg/mg) compared to the posterior region (221.0 ± 124.9 μg/mg) (p = 0.045) across sexes and in males (339.6 ± 170.6 μg/mg) compared to females (204.5 ± 130.7 μg/mg) (p = 0.006) across regions. Anterior failure stress (1.1 ± 0.7 MPa) was larger than posterior failure stress (0.6 ± 0.4 MPa) (p = 0.024). Regional differences confirm the presence of a mechanically and compositionally distinct temporomandibular ligament. Baseline sex-specific differences are critical for etiological investigations of sex disparities in TMJ disorders. These results have important biomechanical and clinical ramifications, providing critical baseline tissue material properties, informing the development of TMJ musculoskeletal models, and identifying new areas for etiologic investigations for temporomandibular disorders.

Digital anatomy table in teaching-learning process of the temporomandibular joint anatomy.

The use of teaching resources and digital objects has gradually been incorporated into dental schools. This study aimed to evaluate the digital anatomy table in teaching-learning process of the temporomandibular joint (TMJ) anatomy and the student's perception regarding this resource. A cross-sectional study was conducted on 41 undergraduate dental students. Knowledge assessment tests were applied at different time intervals: before and after the TMJ theoretical class, after the practical class on prosected specimens and after the use of digital anatomy table. The medians of the scores obtained in the three groups (theoretical class, practical class and digital table) were descriptively analysed and submitted to Wilcoxon, Kruskal-Wallis and Student-Newman-Keuls statistical tests. The perception survey was conducted at the end of the study. When the teaching strategies were compared amongst each other, the medians of the scores with the digital anatomy table were significantly higher than after the theoretical and practical classes. At the end of the research, there were no differences amongst the three groups (theoretical class, practical class and digital table). Regarding the perception, the majority of the students reported that the digital anatomy table helped them to understand the content of the theoretical class. It was concluded that learning with the use of the digital anatomy table did not increase the knowledge of dental students with respect to the TMJ anatomy. The students' perceptions of the digital anatomy table were positive and that it could be used as an additional resource in the teaching-learning process.

Improved access in minimally invasive temporomandibular joint surgery through a novel endaural template

BackgroundDigitally designed surgical templates for minimally invasive temporomandibular joint (TMJ) surgery (MITMJS) are a promising tool for improving the safety of these procedures. Given the TMJ anatomy, the template fitting and intraoperative overview are the most important issues for a safe surgery. This article is a technical advance article that aims to describe an endaural surgical template based on the Moses approach as a possible solution in TMJ surgery.MethodsThree patients with internal derangement were treated with the guidance of a MITMJS template based on cone beam computed tomography (CBCT) and a surface imprint of the periauricular region. None of the patients needed an additional open surgical procedure. Fitting of the templates was judged in terms of position and rotational stability. Surgical side effects and complications were recorded for each patient.ResultsThe template design and clinical use were satisfactory for MITMJS. The templates showed satisfying fit and good visibility. In the study cohort, no bleeding, facial nerve injury, or other complications occurred after the procedure, and no visible scars were noted postoperatively.ConclusionOur feasibility report on template-guided MITMJS shows a promising new application of templates. It points to improved access in arthroscopy or arthrocentesis of TMJ surgery through endaural access with an increased level of safety during surgery.

Temporomandibular joint anatomy: Ultrasonographic appearances and sexual dimorphism.

Temporomandibular joint (TMJ) dysfunction is common, with a greater prevalence in females. While magnetic resonance imaging (MRI) is commonly used for clinical investigation, ultrasonography represents a potential alternative in some clinical scenarios. We designed a protocol for ultrasonographic evaluation of the TMJ and assessed its reliability. Presentation was compared between the sexes to establish whether an anatomical dichotomy underlies the female preponderance of TMJ dysfunction. Ultrasound imaging of the TMJ was carried out in the longitudinal and oblique planes. Standard images were produced using model skulls and healthy volunteers. Measurements were made between the temporal bone, mandibular condyle, joint capsule and overlying skin, as well as of condylar translation during mouth opening. Both joints were scanned in 50 healthy volunteers. Measurements were repeated to evaluate reliability. A novel classification system was used to assess lateral condylar morphology. The protocol facilitated reliable visualization of key anatomical features of the TMJ (average intraclass correlation coefficient=0.75, =5.4E-03). Distribution of condylar morphology differed between the sexes. The capsular-cutaneous distance ('joint depth') and condylar-temporal bone distance ('interarticular distance') were significantly greater in males than in females. Ultrasonography provides reliable views of the TMJ in two planes: longitudinal and oblique. Observed sexual dimorphism in TMJ anatomy might be associated with the female preponderance of dysfunction. With a standardized scanning protocol, ultrasound could provide a rapid, cost-effective alternative to MRI as a point-of-care imaging tool in TMJ clinics.

Acupuncture in Temporomandibular Disorders Painful Symptomatology: An Evidence-Based Case Report.

Temporomandibular dysfunction (TMD) is complex and multifactorial. Its etiology involves various factors, such as malocclusion, psychological patterns, parafunctional habits, and the temporomandibular joint anatomy. Symptoms include myofascial pain, joint clicking, mouth opening limitation, headaches, earaches, and neck pain, comprising one of the greatest causes of nondental pain. Acupuncture has been used to treat these conditions by acting locally both in muscle relaxation and pain management as well as reaching physical, mental, and emotional balance. The aim of this study is to present a brief literature review reporting the efficacy of acupuncture on TMDs and a case report in which the painful symptomatology of TMD was treated with a systemic protocol, based on scientific evidence and concepts of traditional Chinese medicine. Acupuncture may be a complementary treatment for TMD, and in this case report, it eliminated the patient’s painful symptomatology.

Total Temporomandibular Joint Replacement and Simultaneous Orthognathic Surgery Using Computer-Assisted Surgery.

Disorders of the temporomandibular joint (TMJ) are frequent and are usually associated with other disorders of the facial skeleton. Surgery might be needed to correct TMJ anatomy and function and, in cases where pathologies coexist, a two-stage corrective surgery might be needed. However, the current fashion of single-stage procedures is feasible with the aid of new technologies such as computer-assisted surgery (CAS). This is a step forward toward performing complex procedures such as a TMJ replacement with simultaneous orthognathic surgery. CAS allows designing patient-fitted prosthesis and more predictable and accurate surgeries. Moreover, intraoperative development can be controlled in real time with intraoperative navigation, and postoperative results can be measured and compared afterwards. The primary purpose of this article is to present the protocol used in our institution for orthognathic surgery associated with unilateral and bilateral TMJ replacement with patient-fitted prostheses guided with CAS. We present two cases to illustrate our protocol and its results. In the first case, the difference in millimeters between planning and surgical outcomes was 1.72 mm for the glenoid component and 2.16 mm for the condylar prosthesis; for the second case, differences in the right side were 2.59 mm for the glenoid component and 2.06 mm for the ramus, and in the left side, due to the anatomy the difference was a little greater, without clinical significance. Combined surgery of the midface and mandible with total TMJ replacement is feasible and beneficial for the patient. CAS facilitates the planning and design of custom-fit prosthesis and execution of these procedures.

Protocol for fully digital and customized management of concomitant temporomandibular joint replacement and orthognathic surgery

End-stage temporomandibular joint (TMJ) disease is caused by a multitude of pathological processes that impair TMJ anatomy and function. In many cases, end-stage TMJ disease and dentofacial skeletal deformities coexist. The optimal treatment for such conditions is total alloplastic joint replacement and orthognathic surgery. Such procedures have historically been conducted in two separate stages. Furthermore, while technological improvements resulting from the widespread adoption of virtual reality initially led to significant improvements in the field of orthognathic planning, the adoption of virtual design techniques to optimize TMJ reconstruction was a later achievement. Therefore, planning for TMJ replacement and orthognathic surgery did not develop in parallel, leading to various combinations of planning for orthognathic surgery and TMJ replacement with the aim of performing both procedures simultaneously in one stage. Nowadays, improvements in virtual planning and three-dimensional printing have allowed these procedures to be conducted in the same surgical step based on fully digital planning and entirely customized surgery. This paper introduces a fully digital protocol for the treatment of end-stage TMJ disease and associated acquired dentofacial deformities, in which all surgical steps are customized and the whole surgery is performed in succession using automated procedures, thanks to the combined use of virtual surgical planning, surgical guides, custom-designed TMJ prostheses, and patient-fitted osteosynthesis devices.

Effect of Sustained Joint Loading on TMJ Disc Nutrient Environment

The temporomandibular joint (TMJ) disc nutrient environment profoundly affects cell energy metabolism, proliferation, and biosynthesis. Due to technical challenges of in vivo measurements, the human TMJ disc extracellular nutrient environment under load, which depends on metabolic rates, solute diffusion, and disc morphometry, remains unknown. Therefore, the study objective was to predict the TMJ disc nutrient environment under loading conditions using combined experimental and computational modeling approaches. Specifically, glucose consumption and lactate production rates of porcine TMJ discs were measured under varying tissue culture conditions (n = 40 discs), and mechanical strain-dependent glucose and lactate diffusivities were measured using a custom diffusion chamber (n = 6 discs). TMJ anatomy and loading area were obtained from magnetic resonance imaging of healthy human volunteers (n = 11, male, 30 ± 9 y). Using experimentally determined nutrient metabolic rates, solute diffusivities, TMJ anatomy, and loading areas, subject-specific finite element (FE) models were developed to predict the 3-dimensional nutrient profiles in unloaded and loaded TMJ discs (unloaded, 0% strain, 20% strain). From the FE models, glucose, lactate, and oxygen concentration ranges for unloaded healthy human TMJ discs were 0.6 to 4.0 mM, 0.9 to 5.0 mM, and 0% to 6%, respectively, with steep gradients in the anterior and posterior bands. Sustained mechanical loading significantly reduced nutrient levels (P < 0.001), with a critical zone in which cells may die representing approximately 13.5% of the total disc volume. In conclusion, this study experimentally determined TMJ disc metabolic rates, solute diffusivities, and disc morphometry, and through subject-specific FE modeling, revealed critical interactions between mechanical loading and nutrient supply and metabolism for the in vivo human TMJ disc. The results suggest that TMJ disc homeostasis may be vulnerable to pathological loading (e.g., clenching, bruxism), which impedes nutrient supply. Given difficulties associated with direct in vivo measurements, this study provides a new approach to systematically investigate homeostatic and degenerative mechanisms associated with the TMJ disc.

Nearthrosis in true long-standing temporomandibular joint dislocation; a report on pathogenesis and clinical features with review of literature

The behavior and function of the condyle are not the same in every type of temporomandibular joint (TMJ) dislocation. Acute displacement or dislocation of the condyle is not a rare incident, and the treatment modalities have been well known by physicians for a long time. Chronic dislocation of the condyle is considered a relatively common entity for which treatment may indispensably be surgical intervention. Type of dislocation, duration and the number of episodes are taken into account while constructing the treatment plan.Chronic dislocation that has been left untreated for a long time is a relatively less often encountered type exhibiting difficult clinical conditions for treatment. This type of dislocation is usually seen in elderly patients with poor general health conditions and can be classified as “long-standing dislocation.” In this clinical condition, after having some chronic dislocation episodes, the condyle leaves the original fossa, sits in the anterior part of the eminence permanently, creates a new fossa and never gets back to the original place again. Duration is the most important criterion in classifying long-standing dislocations and has a great effect on decisions regarding the type of management. The relevant literature includes few reports, most of which speculate upon “duration,” which varies on a large scale ranging from 5 weeks to 33 years. There has been neither an agreement on time span within which long-standing dislocation develops, nor a universally accepted definition for what “long-standing” is indeed meant to be. On the other hand, in some cases, the condition has been named “true long-standing dislocation” due to some permanent pathological changes that the TMJ undergoes, such as pseudoarticulation/nearthrosis/false joint/neo-joint.In this paper, management of true long-standing/permanent dislocation in two patients, whose conditions lasted more than 1 year and resulted in permanent changes in TMJ anatomy, is presented. Due to the poor general health condition of the two elderly patients, they were treated in the most conservative way possible. In one of the patients, eminectomy and head-gear application were used to attain gradual relocation of the condyles. Rehabilitation of masticatory function of the other patient was improved prosthetically.

In vivo prediction of temporomandibular joint disc thickness and position changes for different jaw positions.

Temporomandibular joint disorders (TMD) are common dysfunctions of the masticatory region and are often linked to dislocation or changes of the temporomandibular joint (TMJ) disc. Magnetic resonance imaging (MRI) is the gold standard for TMJ imaging but standard clinical sequences do not deliver a sufficient resolution and contrast for the creation of detailed meshes of the TMJ disc. Additionally, bony structures cannot be captured appropriately using standard MRI sequences due to their low signal intensity. The objective of this study was to enable researchers to create high resolution representations of all structures of the TMJ and consequently investigate morphological as well as positional changes of the masticatory system. To create meshes of the bony structures, a single computed tomography (CT) scan was acquired. In addition, a high-resolution MRI sequence was produced, which is used to collect the thickness and position change of the disc for various static postures using bite blocks. Changes in thickness of the TMJ disc as well as disc translation were measured. The newly developed workflow successfully allows researchers to create high resolution models of all structures of the TMJ for various static positions, enabling the investigation of TMJ disc translation and deformation. Discs were thinnest in the lateral part and moved mainly anteriorly and slightly medially. The procedure offers the most comprehensive picture of disc positioning and thickness changes reported to date. The presented data can be used for the development of a biomechanical computer model of TMJ anatomy and to investigate dynamic and static loads on the components of the system, which could be useful for the prediction of TMD onset.