Comparative analysis of different types of occlusal splints for the management of sleep bruxism: a systematic review

Temporomandibular disorders (TMD) are a group of conditions that cause pain and dysfunction in the temporomandibular joint (TMJ) and surrounding muscles [1]. TMDs are often associated with biomechanical issues such as malocclusion, in which the teeth are not properly aligned when the jaws are closed. TMD can also be caused by bruxism (long-term teeth grinding or clenching) and abnormal jaw growth patterns in children [2]. Sleep bruxism is commonly characterized by rhythmic or non-rhythmic grinding or clenching of the teeth while asleep [2, 3]. In otherwise healthy individuals, it is not considered a disorder but may be a risk factor for negative oral health consequences like TMD [4‐6]. In the study by Dias et al. [7], sleep bruxism was reported with a 67.6% occurrence of degenerative changes in the temporomandibular joint. These changes lead to pain, stiffness, reduced range of motion, and clicking or popping sounds in the jaw [7‐9]. Sleep bruxism is also reported to affect sleep patterns and the general quality of life [3, 10].

Several therapies, including occlusal splints, have been used to manage sleep bruxism and temporomandibular disorders, including occlusal splints [11]. Occlusal splints, often night guards, are dental appliances that function as protective barriers. Their primary purpose was to minimize the detrimental consequences of bruxism by obstructing tooth-to-tooth contact during sleep [11]. Various occlusal splints are available to accommodate individuals' specific requirements and preferences [12].

Occlusal or bite splints, used for the management of TMD, are typically made from materials like acrylic [11]. The splints provide a barrier between dental arches to minimize the impact of temporomandibular disorders. Since these disorders have adverse symptoms like pain, the cushioning effect of the splints helps improve comfort and minimizes accompanying symptoms [11, 13]. Splints are customized to suit the different needs of patients by taking impressions of patients' teeth, which are used to fabricate customized splints for specific bite patterns. Splints customization ensures optimal comfort and compliance [14].

Traditional acrylic splints are known to exhibit durability and can endure the stresses exerted during bruxism episodes [15]. Soft splints are often fabricated using soft substances such as silicone and are renowned for their exceptional comfort [16]. These splints provide a cushioning mechanism that mitigates the impact of clenching and grinding on the teeth and jaws [16]. There has been growing interest in using digital splints that include materials such as Polyether Ether Ketone (PEEK), owing to their precise nature and the ability to customize them according to individual patients [15]. The production of these splints utilizes sophisticated digital technology that guarantees a customized fit that maximizes both comfort and efficacy [15].

Besides occlusal splints, there are other methods employed in TMD management. These include massaging muscles surrounding the jaw, Botox Injections, transcutaneous electrical nerve stimulation (TENS), acupuncture, and low-level laser therapy (LLLT) [17‐21]. Additionally, biofeedback has been used to manage TMD to help patients learn to control their masticatory muscle activity and reduce pain [22, 23]. Biofeedback can also help promote relaxation and regulate muscle tension [22, 24].

The rationale for conducting this systematic review was based on the need to assess and compare different occlusal splints used to treat sleep bruxism [12]. Sleep bruxism has oral health implications, including tooth wear, fractures, and orofacial discomfort, which require effective interventions [10]. The utilization of occlusal splints has emerged as a significant treatment modality. Nevertheless, various splints exist, each possessing distinct benefits and drawbacks [25]. This review aimed to evaluate and compare the efficacy of several occlusal splints in managing sleep bruxism. This would provide valuable insights for clinical practitioners and contribute to evidence-based decision-making in treating sleep bruxism.

The main objective of this systematic review was to comprehensively evaluate and consolidate the current body of literature to compare the effectiveness of different occlusal splints in treating sleep bruxism. It further aims to address the following research questions:

The Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines [26] were used to identify published studies that explored and compared different occlusal splints for managing sleep bruxism. The protocol used for this systematic review was the registered International Platform of Registered Systematic Review and Meta-Analysis Protocols (INPLASY) (20231000489). To examine the existing information on various types of occlusal splints, the PICO framework [27] was defined as follows:

This systematic review presents a comparative examination of various occlusal splints utilized in managing sleep bruxism. This review demonstrated that adjustable splints, such as full-occlusion biofeedback splints, are more effective in reducing sleep bruxism episodes, improving patient-reported symptoms, and enhancing overall well-being. The impact of occlusal splints on electromyographic activity varies depending on the splint used and the individual's physiological reactions. Specific splints, such as the modified anterior splint, have shown greater efficacy in lowering muscle activity [37]. Conversely, soft occlusal splints have demonstrated varied outcomes. Therefore, the potential adverse effects should be considered on an individual basis. The selection of a splint should be well deliberated, considering individual requirements and preferences [44].

Critical analysis and synthesis of the results of multiple studies are essential for a comprehensive understanding of the effectiveness of occlusal splints in managing sleep bruxism. Bergmann et al. [36] showed that full-occlusion biofeedback splints effectively reduced sleep bruxism episodes. These results are consistent with previous research and the idea that splints may be an effective intervention to reduce the frequency of bruxism episodes during sleep [44].

Interestingly, other studies have shown no statistically significant differences in the impact of different splint devices on managing sleep bruxism [31, 33]. However, both splint devices significantly reduced the bruxism episodes upon their insertion. The lack of statistically significant differences may have been due to heterogeneity in the patient population. Bruxism is a complex condition influenced by stress, anxiety, and occlusal conditions. Including patients with varying degrees of bruxism may have affected their response to treatment.

De Paula Gomes et al. [35] and Kolcakoglu et al. [38] investigated sleep bruxism. They reported that improvement in the severity of signs and symptoms was associated with the use of combined therapies and soft occlusal splints. These findings highlight the possibility of integrating several therapies to mitigate the symptoms related to sleep bruxism and temporomandibular joint disorders [35]. Moreover, soft splints may more effectively mitigate symptoms in younger individuals diagnosed with bruxism [38]. In contrast, Dalewski et al. [32] discovered that Okeson's Stabilization Splint and Bimaxillary Splint had a comparable impact in reducing pain factors related to sleep bruxism. This implies that both splint designs can effectively alter the pressure pain threshold in patients diagnosed with bruxism [32].

Occlusal splints are also known to undergo changes over time. Their continuous contact with teeth during mastication and grinding leads to abrasion and changes in the splint's surfaces. The materials used in making both traditional and 3D-printed splints are also subject to aging. This is primarily due to exposure to oral fluids and temperature variations. Aging results in changes in the splints' mechanical and chemical properties, reducing their effectiveness [45]. The choice of the splint material thus plays a crucial role in determining splint longevity and performance. 3D-printed splints made of biocompatible polymers are preferred due to their proven stability in the oral environment [46, 47]. The better surface finish of 3D-printed splints also improves wear resistance and comfort.

This review provides valuable insights into the effectiveness of occlusal splints in managing sleep bruxism. Nevertheless, diverse therapies, limited follow-up durations, and inconsistent outcome measures across studies underscore the need for more extensive research in this field. The results of this study indicate that occlusal splint therapy is a viable treatment approach for sleep bruxism. However, further research is needed to understand its long-term effects, patient-reported outcomes, and adverse effects. The management of sleep bruxism requires careful consideration of several factors, highlighting the need to customize treatment approaches to suit the unique demands of each patient.