In a joint project, the Prof. Stehling Institute for Imaging Diagnostics and the ANOVA Institute for Regenerative Medicine have developed new diagnostic and treatment approaches for a previously poorly resolved medical problem: The chronically painful temporomandibular joint.
Due to the complexity of the temporomandibular joint and its diverse conditions, patients often suffer chronically, sometimes for decades, from pain and functional limitations without finding an adequate medical solution. This motivated us to combine modern diagnostic and therapeutic methods in order to provide patients with temporomandibular joint disorders an effective approach to treating their complaints.
Risk factors
- Iodine deficiency
- Family history
- Autoimmune diseases
- Radiation exposure
The temporomandibular joints
Cause of various complaints
The temporomandibular joints (TMJ) are the bilateral hinge joints through which the lower jaw is movably attached to the rest of the skull. The mobility of the lower jaw enables chewing and speaking.
Due to the strong masticatory muscles, the temporomandibular joint is exposed to strong forces, which can lead to mechanical malfunctions and accelerated wear, especially in the case of asymmetries in the jaw and tooth area.
With TMJ syndrome, patients notice intermittent pain in the joint in front of the ear or in the muscles around the joint when they speak or chew. In severe cases, patients can no longer open their mouth properly and chewing is no longer possible: food is swallowed unchewed or patients are limited to a liquid diet.
The complex structure and function of the temporomandibular joints is often poorly understood, even by doctors. The joint has four main components: Bone (with cartilage), discus, muscles and ligaments. Pathological changes in muscles and ligaments are often overlooked even by experienced doctors.
Dynamic MRI of the Tempromandibular Joints
Dynamic MRI of the temporomandibular joints reveals pathological changes at an early stage so that effective treatment can be initiated.
Bone, Cartilage and Articular Disc Conditions
First of all, the temporomandibular joint, like any other joint, has a cartilage covering that surrounds the joint. This articular cartilage ensures that the joint glides smoothly and acts as a protective cushion for the underlying bones where they meet as a joint.
In addition, as in the knee, there is a natural spacer in the joint called the “discus articularis” (articular disk of the temporomandibular joint). This is a structure similar to the “meniscus” in the knee, which moves with the joint-forming head of the lower jaw when the jaw is opened and closed and helps to evenly transfer the immense loads that can occur when chewing, thus protecting the joint.
As with any other joint in the body, the cartilage and/or the disc in the temporomandibular joint can be injured or damaged by wear and tear, leading to painful signs of wear and tear – osteoarthritis.
Treatment options
While joint replacement with an endoprosthesis (artificial joint) is now standard for other joints, this is difficult for the temporomandibular joint and is associated with unsatisfactory functional results.
Stem Cell Therapy for Temporomandibular Joint Arthrosis
One modern treatment option for temporomandibular joint degeneration is the use of stem cells. These can regenerate cartilage and the articular disc, or at least slow down the progression of osteoarthritis so that joint replacement can be delayed.
In cooperation with the ANOVA Institute for Regenerative Medicine, stem cell treatments of temporomandibular joints can be carried out. ANOVA IRM is the first and currently the only institution in Germany to have an official license for the production and treatment of corresponding stem cell products.
Diseases of Muscles and Ligaments
Another important component of the temporomandibular joint are the muscles that move it. When chewing, these muscles have to work together with millisecond precision to enable the teeth to open and close and make lateral grinding movements. Overloading or incorrect loading can disrupt the biomechanics of the muscles, for example through muscle cramps – permanent contractions of muscle parts, or through muscle fiber tears and associated inflammation. These dysfunctional muscle parts are also called “trigger points”. As in other muscles, these changes are associated with considerable pain.
The tendons through which the muscles attach to the corresponding bones can also develop tears, degenerative changes and inflammation due to overloading and incorrect loading, which can lead to pain and impaired biomechanics.
Ligaments stabilize the joint by guiding it and preventing excessive movements for which it is not designed. The temporomandibular joint has many ligaments that are often not taken into account in the treatment of TMJ disorders.
The last two key components, the muscles and ligaments, are often overlooked by doctors, even though they are the key to successful treatment of TMJ disorders.
Treatment Options
Targeted physiotherapeutic measures can work wonders for the temporomandibular joint. This first requires a detailed diagnosis, which is carried out using dynamic MRI and a dental examination of the temporomandibular joints, the upper and lower jaw and the teeth.
Phasiotherapeutic treatment should then be carried out by an expert specializing in the temporomandibular joints in order to bring about rapid relief of the symptoms and improvement in function.
Stem Cell Therapy for Arthritis of the Temporomandibular Joint
Muscles, vision and ligaments can also benefit from stem cell treatment. This must be decided on a case-by-case basis. Stem cell therapy can help with inflammatory changes and loss of muscle mass (atrophy) in particular.
Precise diagnostics are the key to understanding temporomandibular joint disorders – and their successful treatment
Magnetic resonance imaging (MRI) is the key to the precise diagnosis of diseases of the temporomandibular joints (TMJ). In contrast to X-rays and computed tomography (CT), which only depict the bony structures of the TMJ, MRI provides comprehensive information about all anatomical elements of the TMJ. Particularly important in diagnostics are the imaging of the articular disc, ligaments, joint capsule, as well as the muscles and tendons of the TMJ.
However, there are only a few specialists in the world who are able to examine the TMJ with MRI and analyze this complex data. Dr. Markus Sens is one of these experts and has worked intensively on the diagnosis and treatment of TMJ over the last few decades.
Dynamic MRI of the Temporomandibular Joints
State-of-the-art diagnostics show pathological functional states of the temporomandibular joints in movement studies
However, MRI makes even more possible. Using dynamic examination techniques, the complex movement of the TMJ when opening and closing the mouth can be visualized in real time. In particular, the movement of the discus articularis, which is often malformed and displaced in diseases of the TMJ, can be assessed.
Figure a) shows an example of such a dynamic MRI. The MRI images were taken in close temporal sequence when opening and closing the mouth. The movement study shows in detail the forward displacement of the temporomandibular joint head from the articular fossa onto the articular tubercle, whereby the sliding movement is accompanied by the articular disc. Overall, the mouth opening normally represents not only a rotation in the TMJ, but also a forward translation. This is what makes an effective grinding movement of the teeth possible in the first place.
Dynamic MRI of the left temporomandibular joint shows the complex forward and backward movement of the mandible with the condyle and the articular disc in and out of the socket.
Stem cell therapies enable pain reduction, improved function and regeneration of the temporomandibular joints without surgery
In the meantime, numerous scientific studies have shown that stem cell therapies can be successfully used to treat temporomandibular joint wear – also known as osteoarthritis. This is not really a surprise, as stem cells have also been used successfully for years to treat osteoarthritis in other joints.
In a study published in 2020 from the Klinikum Hamburg Eppendorf, German scientists were able to show that mesenchymal stem cells (mesenchymal stromal cells – MSC) injected into arthritic temporomandibular joints, together with or without hyaluronic acid, had a statistically significant positive effect on the regeneration of articular cartilage in the TMJs treated with them. Notably, a significant regeneration of the joint cartilage could be detected after a single application.
However, not all stem cells are the same. So far, mesenchymal stem cells, whose anti-inflammatory and regenerative effects have been scientifically proven in animal models as well as in initial clinical studies, have been the most frequently investigated.
Bone marrow stem cells, which can be obtained as a bone marrow concentrate from the pelvic bone, have also been used successfully for years to treat osteoarthritis, e.g. of the shoulder, hip and knee joints. Recent studies show that they are also effective in osteoarthritis of the TMJ.
As early as 2017, Zaki and colleagues, among others, were able to show that bone marrow stem cells can lead to extensive freedom from inflammation and normalization of the TMJ in cases of experimentally induced arthritis of the temporomandibular joints in experimental animals. This is due to the pronounced anti-inflammatory effect of the stem cells and the regeneration of the joint cartilage and the articular disc that they induce.
ANOVA Institute for Regenerative Medicine
Germany’s first institution with a manufacturing license for mesenchymal stem cell secretome
The latest approach is the use of the so-called “stem cell secretome”, also referred to by experts as stem cell therapy 2.0. The stem cells are stimulated in the laboratory, outside the body, to secrete large quantities of their secretome. This secretome is the active ingredient of stem cells, with the help of which they exert their anti-inflammatory and regenerative effect. The secretome contains hundreds of bioactive substances, cytokines and microRNAs through which the stem cells act. The original idea that stem cells applied to the body replace damaged or dead cells in the body is now outdated.
The advantage of treatment with stem cell secretome is that it is cell-free and therefore easy to store. In addition, the formation of tumors that is often feared in stem cell treatments is thus ruled out.
In a study published in 2019, Zhang and colleagues showed that exosomes secreted by mesenchymal stem cells, a part of the stem cell secretome, are an effective treatment method for osteoarthritic changes of the temporomandibular joint.
