For more than a century, dentists have been using occlusal splints (OSs) for treating jaw fractures, muscle, and temporomandibular disorders (TMDs). However, there is still a lack of clarity and substantial disagreements on the type, indication, and prognostic value of these splints. Positive outcomes such as reduced pain and improved mouth opening are the commonly reported results in a wide range of publication types. These outcomes are particularly important, as they may impact the patient’s quality of life considerably, and may have an effect on overall health. OS are synonymously referred to as dental splints, bite guards, oral orthotics, orthotic appliances, temporomandibular joint (TMJ) stabilization appliances or permissive splints, and oral orthopedic appliances, among others. OS is generally considered to be a conservative management method for TMDs. A conclusive evidence-based concept is yet to emerge. ^, Evidence seems to be lacking as to the most desired and efficient splint designs.

Numerous studies suggest only limited evidence supporting the utility of OS in treating TMDs. The modest effectiveness sometimes observed may be attributed to coupling effects of adjunctive therapies, such as physical therapy, behavioral modifications, or pharmacologic interventions, rather than the OS itself. More robust literature is desired in this regard to have a clearer understanding of their mechanisms. ^,,, The aim of this narrative review is to explore literature from the days the word “splint” was coined, initially in orthopedic literature and then later, “occlusal splint” in the dental literature. The article covers the historic background of OS since the mid-seventeenth century to the present, their various types, proposed modes of action on myogenous and intracapsular TMDs. We also looked at their indications in parafunctional habits and preventive prosthodontics, along with the evidence for their efficacy. The authors searched 6 major electronic databases, namely PubMed, Google Scholar, Web of Science, Embase, Medline-Ovid, and Scopus for articles on OS, oral splints/oral orthotics, and oral orthopedic devices. The types of studies included review articles, case series, systematic and scoping reviews, and meta-analysis published in the English language. The time range of the search was from 1964 through May 31, 2025. The “current literature” mentioned in this article henceforth would indicate literature review from year 2000 onward. Duplicates and nonfocused articles were eliminated. Considerable controversy regarding the use of terminologies such as “splint” or “orthotics” exists in literature. The terminology of “orthotic” may be more desirable than the term “splint.” In general, for the ease of communication, the term “occlusal splints” will be used in this study, to represent all types of oral appliances/splints/orthotics, and so forth.

Various definitions of OS are found in the literature. Interestingly, the uses, as they are defined by medical and dental specialties and specialty organizations, vastly vary as well, which are summarized in Table 1 in the chronologic order.

The evolution of splints dates back to the time of the ancient Egyptians and Aztecs around 1500 bc. They used large leaves secured with leather straps or resin paste and wooden splints for the treatment of fractures. In the fifth century bc , Hippocrates developed a manual method for immobilizing mandibular fractures. Furthermore, Hippocrates created a distraction splint to reduce tibial fractures.

OS have evolved over the past several decades. The use of the term “occlusal splints” for the management of TMDs came into existence in the mid-1930s. After World War II, dentists incorporated the use of OS in the management of TMDs. However, the current therapeutic approaches for TMDs are evolving from traditional mechanistic dental concepts to evidence-based biopsychosocial models that prioritize interdisciplinary and multimodality management. The evolutionary timeline of OS and related concepts detailed in Fig. 1 depicts the time range from fifth century bc to year 2000. Tables 2 and 3 summarize current literature from year 2000 onward till date. These tables compare the levels of evidence between conclusive and nonconclusive articles regarding the effectiveness of splints in managing temporomandibular disorders (TMDs).

Occlusal splints: evolutionary timeline of occlusal splints and related concepts. CR, centric relation; NTI-TSS, nociceptive trigeminal inhibition tension suppression system; TMD, temporomandibular disorder.

• 1.

  Full arch (maxillary or mandibular) splints:

  • a.

    Flat plane stabilization splints (SSs)

  • b.

    Mandibular anterior repositioning splint/mandibular advancement device

  • c.

    Night guard

• 2.

  Sectional arch coverage splints:

  • a.

    Anterior bite plane splints

  • b.

    Pivot splints/posterior bite plane splints

  • c.

    Deprogrammer

  • d.

    Nociceptive trigeminal inhibition tension suppression system (NTI-TSS)

Multiple designs of OS have been used and described in the literature, and it seems that a full coverage hard acrylic appliance that rests either on mandibular or maxillary arches, with bilateral equal contacts against the opposing arch, may have the most stable therapeutic outcomes, with minimal chances of occlusal changes. Full-arch HSS is better than the sectional splint (eg, NTI-TSS), as side effects such as partial covering, occlusal discrepancies, open bites, traumatic movement, and possible aspiration hazards are associated with sectional splints, according to the literature. ^, Studies revealing the effectiveness of sectional appliances show significant operator bias, with weak evidence supporting this claim.

Stabilization Splint

Currently, the most commonly prescribed splints seem to be SS, traditionally indicated for masticatory myalgia and arthralgia “to protect the dentition and/or dental prosthesis and supporting structures from potential deleterious effects of bruxism.” ^,,,, The first challenge while looking at this literature is to predictably define the term “stabilization.” What are we exactly stabilizing? Is it the disc, the TMJ, the condyle, or the entire mandible? The apparent fallacies of these studies seem to emanate from the lack of homogeneity, standardization, and calibration of such terms, as they are applied in research.

The most general definition of joint stability is the ability of a joint to maintain an appropriate functional position throughout its range of motion. A joint is stable if it can carry the required functional loads without pain and produce joint contact forces of normal intensity on the joint surfaces. Stable joints have one position of joint equilibrium for any particular functional loading situation. A similar analogy of stabilizing the TMJ, with the aid of SS, has been proposed to potentially reduce the “parafunctional load” on TMJ and masticatory muscles. Establishing proper occlusal guidance with SS is proposed to be effective for patients with bruxism, local myalgia, and occlusal wear facets without psychological and systemic contributory factors. ^,, However, there is a significant lack of evidence as to the scientific merit of these “guidelines.” There seems to be a lack of concrete evidence as to the exact mechanism of action or the effects of SS on the masticatory apparatus.

It is possible (and even probable) that SS distributes parafunctional occlusal forces, limits muscle strain, and protects the teeth from further wear. SS is proposed to be beneficial when bruxism and myalgia coexist with a significant stress component, and the benefit may be primarily mechanical in terms of dissipation of parafunctional forces. These appliances may further help facilitate active control over the patient’s daytime parafunctional habits (primarily by increasing awareness and alertness) and further help reduce the sleep bruxism movements. ^, Improvements in joint sounds, headaches, joint and muscle pain, posture, and neck discomfort have also been reported at the 1 year follow-up mark with SS therapy. ^,

It has been reported that masseter muscle activity shows reduction (as measured by surface electromyogram [EMG]) for a short term of 1 month. Further, it has been hypothesized that this reduction may aid in symptom relief of TMD-associated joint and muscle pain. However, these apparent results are subject to significant variations in their interpretations. ^,, In addition, multiple highly validated studies, including systematic reviews with meta-analysis, failed to reveal any such possible correlations. ^,,,,,,,, The current literature review on SSs is given in Table 4 .

Table 4

Stabilization splints: review of the current literature

Author, Year	Type of Study	Diagnosis	Splint Type/Time	Result	Level of Evidence a
Katyayan et al, 2014	RCT	TMDs	SS ± CSL and MME/6 mo	SS is no more beneficial than CSL + MME over 6 mo	I
Nagata et al, 2015	RCT	TMDs	NS ± SS	SS’s superiority over multimodal therapy was not confirmed	I
Qvintus et al, 2015	RCT	TMD-related facial pain	CSL + MME ± SS/1 year	SS is not effective compared to CSL + MME alone	I
Wahlund et al, 2015	RCT	Myofascial pain	SS/6 mo	SS is more effective than RT for adolescents with TMD pain on self-assessment of therapeutic improvement	I
Devi et al, 2017	Single blinded RCT	ADDwR	ARS vs HSS vs SSS/10 wk	HSS splint can be used in ADDwR for quicker and more effective results	I
Pficer, 2017	Meta-analysis	TMJ arthralgia/myofascial pain	SS vs NOS, PT, BT, CSL, and so forth	SS only provided temporary relief for TMDs. Long-term results were comparable to those of other modalities	I
Al-Moraissi et al, 2020	Meta- analysis of RCTs	TMJ arthralgia	OS with multimodal treatment (CSL + HSS)	Moderate to low-quality evidence supports OS’s effectiveness in managing TMDs, suggesting multimodal therapy may yield maximum relief	I
Honnef et al, 2024	Systematic review	Myogenous TMDs	SS	The effectiveness of SS in reducing myogenous TMDs remains unproven	I

Abbreviations: ADDwR, anterior disc displacement with reduction; ARS, anterior repositioning splint; BT, behavioral therapy; CSL, counseling therapy; HSS, hard stabilization splint; MME, masticatory muscle exercise; NOS, nonoccluding splint; NS, nonsplint multimodal therapy; OS, occlusal splint; PT, physical therapy; RCT, randomized control trial; RT, relaxation therapy; SS, stabilization splint; SSS, soft stabilization splint; TMD, temporomandibular disorder; TMJ, temporomandibular joint.

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