Occlusal splints for TMD can now be digitally planned and fabricated. This article describes the process from impression to finished splint.
Digital workflow for fabricating occlusal splints considering orthopedic principles.
The Occlusal Splint: The First Step in Treating Temporomandibular Disorders
When teeth are being straightened, the visible alignment is often the primary focus. However, it is equally important that the teeth meet correctly at the end and that the temporomandibular joints function harmoniously. This is precisely where the occlusal splint comes in. For temporomandibular joint disorders (temporomandibular disorder, or TMD), it is often the first, conservative treatment step — even before actual tooth correction.1 The underlying specialist publication describes this approach and the modern, digital fabrication of the splint. Below, we explain the key points in understandable terms.
What Is an Occlusal Splint?
An occlusal splint is a removable appliance made of rigid acrylic, usually worn in the lower jaw. It deliberately adjusts how the upper and lower jaws relate to each other. In professional terminology, it is also called a craniomandibular orthopedic repositioning appliance (COPA)2 because it guides the mandible and the condyles (the rounded ends of the jaw joint) into a relieved position. Its main purposes are the treatment of TMD and the protection of enamel and the periodontal apparatus.
Why the Splint First—and Only Then the Orthodontic Correction?
Ideally, every orthodontic treatment should be planned from a healthy, physiological position of the temporomandibular joints — professionally called “centric relation” (CR) — and not from the habitual bite position where the teeth currently fit together (the “habitual intercuspation,” CO).3 When a functional disorder is present, there is often a gap between these two positions. The occlusal splint is a reversible measure — meaning it is completely reversible — that first establishes and verifies this healthy joint position. Only when it is clear from which position treatment should proceed does the actual tooth correction begin.
How Is the Correct Position Determined?
The process begins with a thorough functional diagnostic assessment. It starts with a standardized brief test (the “Short Screening Test”)4 and an examination of the interplay between the jaw, musculature, and body posture.5 If abnormal findings emerge, further examinations follow, including imaging procedures if necessary. Based on this foundation, the individual, relieved jaw position is determined, in which the splint is then fabricated.
What Does the Science Say?
The effectiveness of splints for TMD is well documented. A comprehensive review (meta-analysis) showed that stabilizing splints can noticeably reduce pain in both joint-related and muscle-related conditions6 – partly supported by accompanying measures. Splint therapy is thus an established, evidence-based component of TMD treatment.
Fabrication in the Digital Workflow
Modern occlusal splints are increasingly fabricated digitally. First, the upper and lower jaws are captured contact-free in 3D using an intraoral scanner, then the relieving jaw relation is registered. The practitioner plans the splint with millimeter precision on the computer – important here are good, but not excessive, friction (retention) and sufficient material thickness to keep the splint stable. It is fabricated by 3D printing from biocompatible plastic.7 The advantage: very high precision of fit, and a spare splint can be printed alongside without difficulty.
What comes after the splint?
Once the temporomandibular joints are relieved and the healthy position is established, the actual orthodontic correction can begin – today usually with nearly invisible clear aligners. How this function-oriented planning can then be implemented using a virtual articulator is explained in detail in our article on virtual articulators in aligner orthodontics. You can also learn more about the treatment of temporomandibular disorders on our page about TMD treatment. What follows after successful splint therapy – that is, how the established jaw position is permanently stabilized – can be found in our professional publication on follow-up treatment after initial splint therapy. How such a splint is created in practice is shown in our treatment example: TMD pain with digitally fabricated splint.
Sources
- Okeson, J. P. (2015). Evolution of occlusion and temporomandibular disorder in orthodontics: Past, present, and future. American Journal of Orthodontics and Dentofacial Orthopedics, 147(5), S216–S223. https://doi.org/10.1016/j.ajodo.2015.02.007
- Boisserée, W., & Schupp, W. (Hrsg.). (2012). Kraniomandibuläres und muskuloskelettales System. Quintessenz.
- Schupp, W., & Funke, J. (2018). Continuing diagnostics and therapy of the temporomandibular and musculoskeletal system: The rest position of the temporomandibular joint (TMJ) and the therapeutic construction bite vs. the centric bite. Journal of Aligner Orthodontics, 2, 267–281.
- Meyer, G. (2018). Short clinical screening procedure for initial diagnosis of temporomandibular disorders. Journal of Aligner Orthodontics, 2, 91–98.
- Schupp, W., Funke, J., Boisserée, W., et al. (2018). Continuing diagnostics of the temporomandibular and musculoskeletal system (TMS/MSS). Journal of Aligner Orthodontics, 2, 199–213.
- Al-Moraissi, E. A., Farea, R., Qasem, K. A., Al-Wadeai, M. S., Al-Sabahi, M. E., & Al-Iryani, G. M. (2020). Effectiveness of occlusal splint therapy in the management of temporomandibular disorders: Network meta-analysis of randomized controlled trials. International Journal of Oral and Maxillofacial Surgery, 49(8), 1042–1056. https://doi.org/10.1016/j.ijom.2020.01.004
- Lin, R., Yu, C. H., & Sun, J. (2019). Mechanical properties and cytotoxicity of three-dimensional printing polycarbonate for occlusal splints. Shanghai Kou Qiang Yi Xue, 28, 467–471.
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