TMJ disorders often cause pain and limit jaw function. A common treatment involves an oral splint, a custom-made orthotic device worn over the teeth to stabilize the bite and reduce strain on the jaw. This appliance guides the jaw into a more relaxed position, mitigating the effects of clenching or grinding. The appearance and structural variations of these splints relate directly to the materials used and their specific therapeutic goals.
Basic Appearance and Construction
A typical TMJ splint is a clear, custom-fitted dental appliance that covers the biting surfaces of an entire dental arch, usually the upper one. These devices are fabricated in a dental laboratory from an impression of the patient’s teeth, ensuring a snug, precise fit that distinguishes them from generic, over-the-counter mouthguards. The material most commonly used is durable acrylic resin, which is often transparent or slightly tinted to make the splint less noticeable.
The thickness of a custom hard splint is usually a minimum of 2 millimeters, providing enough rigidity to maintain the intended jaw position and withstand forces from clenching. When placed in the mouth, the splint resembles a thick, high-quality retainer, conforming exactly to the contours of the teeth and gums.
Key Visual Differences: Hard vs. Soft Splints
The most immediate visual distinction between splints is based on the rigidity of their construction material. Hard splints are fabricated entirely from strong, rigid acrylic or co-polyester, giving them a polished, glass-like appearance. They are translucent and maintain sharp, defined edges.
Soft or resilient splints, sometimes made from elastic rubber sheets or thermoplastic materials, look more pliable and rubbery. These appliances appear more opaque and may seem slightly bulkier than hard splints. Another variant is the soft-hard splint, which features a soft, cushioning inner layer that rests against the teeth and gums, visually contrasting with a clearer, harder acrylic outer shell.
Distinguishing Features of Functional Types
Beyond material differences, the splint’s intended function dictates its most significant visual features, particularly the design of the biting surface.
Stabilization Splints
Stabilization splints, also known as flat plane splints, cover all teeth in the arch and present a smooth, uniform surface for the opposing teeth to contact.
Anterior Repositioning Splints (ARS)
ARS are visually more complex because they incorporate ramps or inclined surfaces on the biting plane. These features guide the lower jaw forward into a predetermined therapeutic position. The presence of these slopes and ledges makes the ARS appear less uniform and more three-dimensionally contoured than a stabilization splint.
Nociceptive Trigeminal Inhibition (NTI) Splints
A visually distinct appliance is the NTI splint, which is a minimal-coverage device. This type is significantly smaller, covering only the two or four front teeth, typically on the upper arch. The NTI design is characterized by a small acrylic platform or “discluding element” that only allows the opposing front teeth to make contact, preventing the back teeth from touching.