Association Between Occlusal Interferences and Signs and Symptoms of Temporomandibular Disorders in Orthodontically Treated Young Adults-An In-vivo Study
This cross-sectional study of 201 orthodontically treated young adults found a high prevalence and substantial co-occurrence of occlusal interferences and temporomandibular disorder signs and symptoms, though the presence of interferences without TMD suggests a multifactorial etiology rather than a direct causal relationship.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
The human mouth is a complex machine designed for eating, speaking, and breathing, built from bones, muscles, and joints that must work in perfect harmony. At the heart of this system lies the temporomandibular joint, the hinge connecting the lower jaw to the skull. This joint allows the jaw to rotate and slide, enabling the wide range of motion needed for daily life. Sometimes, however, this system develops problems known as temporomandibular disorders. These issues can manifest as pain, difficulty moving the jaw, or audible clicking sounds when opening and closing the mouth. The causes of these disorders are often debated, with one long-standing theory suggesting that the way teeth fit together—specifically, if they hit each other in the wrong order during movement—might be a primary trigger. Orthodontic treatment, commonly known as braces, aims to align teeth into a stable, comfortable bite, yet it remains unclear whether these treatments prevent jaw problems or, in some cases, contribute to them.
A team of researchers at Yenepoya University set out to investigate this relationship by examining young adults who had recently completed orthodontic treatment. They focused on two specific things: the presence of "occlusal interferences," which are moments when teeth collide in an unnatural way during side-to-side or forward jaw movements, and the signs and symptoms of temporomandibular disorders. The study involved 201 participants between the ages of 18 and 30. To find the interferences, the researchers used a simple but precise method: they had patients bite down on dental floss, thin metal foil, and colored marking paper while moving their jaws in various directions. This allowed them to spot exactly where teeth were hitting prematurely. Simultaneously, they assessed the patients for physical signs of jaw trouble, such as joint noises or tenderness, and asked them about symptoms like pain or difficulty opening their mouths.
The results revealed a high frequency of both issues within this group. Nearly 79 percent of the participants showed evidence of occlusal interferences, meaning that even after their teeth were straightened, their jaws still encountered awkward contacts during movement. At the same time, about 69 percent of the group displayed clinical signs of temporomandibular disorders, with the most common finding being a clicking sound in the joint. Just over half of the participants reported experiencing symptoms like pain or trouble opening their mouths. When the researchers looked at the overlap between these two groups, they found a strong connection: the majority of people with jaw interferences also had signs or symptoms of the disorder. For instance, among those with interferences, nearly 87 percent showed clinical signs of the condition.
However, the study also uncovered a crucial detail that challenges the idea that bad tooth contacts are the sole cause of jaw pain. A significant portion of the participants—about 24 percent—had occlusal interferences but reported no symptoms of a disorder. This finding suggests that while misaligned tooth contacts often appear alongside jaw problems, they are not sufficient on their own to cause the disorder. The researchers concluded that the development of temporomandibular disorders is likely multifactorial, meaning it arises from a combination of factors including genetics, stress, and individual physical adaptation, rather than just the way teeth meet. The presence of a jaw problem in someone with perfect tooth contacts, and the absence of a problem in someone with imperfect contacts, indicates that the human body can often adapt to minor dental irregularities without developing pain.
This research does not prove that orthodontic treatment causes jaw disorders, nor does it confirm that fixing the bite will cure them. Instead, it highlights that even after successful treatment, many young adults still have dynamic bite irregularities and a high rate of jaw symptoms. The study emphasizes that while the relationship between tooth alignment and jaw health is significant, it is not a simple cause-and-effect scenario. The authors suggest that future studies should follow patients over time to understand how these factors interact as people age, noting that a single snapshot in time cannot reveal the full story of how these conditions develop. For now, the data supports the view that a comprehensive approach to jaw health must look beyond just the static position of teeth to consider the complex, living system of the jaw and its many influences.
Drowning in papers in your field?
Get daily digests of the most novel papers matching your research keywords — with technical summaries, in your language.