https://medisij.com 31 Shopova et al. (2023). Occlusal splints, retainers and the relation between them – a review article, MEDIS - Medical Science and Research, 2(3), 31-37. doi: 10.35120/medisij020331s UDK: 616.314-008.28-76 Occlusal splints: Bruxism, a common parafunctional habit, arises from a variety of factors including biological, physiological, and exogenous infuences. It can signifcantly impact individuals’ quality of life by leading to dental issues such as tooth wear, frequent dental restoration fractures, and orofacial pain. Clinically, it manifests through symptoms like muscle fatigue in the masseter area, temporomandibular joint pain, ear discomfort, tingling sensations, soreness, or a sense of teeth instability. Despite its prevalence, there isn’t a defnitive and cost-effective clinical method for diagnosing bruxism with reliable diagnostic and technical validity [Koyano]. Two types of bruxism are recognized: static (involving compression only) and dynamic (involving compression and horizontal movements). It can occur during both daytime (primarily static clenching) and nighttime (dynamic grinding) [Okeson]. The term “splint,” according to orthodontic terminology, refers to various devices, appliances, or apparatus employed to stabilize or support teeth or bones. These devices resist motion or displacement of fractured or injured structures [Jacobson]. In the literature, two main categories of splints are described: Okeson splints and Stabilization appliances. The latter category includes Anterior Repositioning Appliances (ARA) or Mandibular Orthopedic Repositioning Appliances (MORA) [Okeson]. Additional types encompass Anterior/Posterior bite planes, Pivoting appliances, and Soft/Resilient appliances made from materials like silicone [Moin, Dhannawat]. Dawson’s classifcation further breaks down splints into permissive splints/muscle deprogrammers, non-permissive splints/directive splints, and pseudo-permissive splints (e.g., Soft splints, Hydrostatic splints) [Dhannawat, Dawson]. The stabilization splint is primarily used to address symptoms related to masticatory dysfunction, encompassing issues like muscle pain, temporomandibular joint (TMJ) pain, clicking, crepitation, restricted movement, and coordination diffculties. This type of splint is typically recommended for continuous wear, except during meals, and can be positioned on either the upper or lower jaw [Al-Ani]. On the other hand, a repositioning splint is employed to address alterations in intermaxillary relationships and muscle function. Joint clicking could result from swift changes in disc or condyle positions during condylar translation. The classic repositioning splint involves placing a vestibular arch on the frontal teeth area, with smooth surfaces distally [Wiliamson]. Anterior bite splints, featuring a horizontal plane at the front, are worn on the upper jaw and only occlude with the lower front teeth. They are used to manage muscular dysfunction and disturbances in occlusal relationships. Additionally, they can serve orthodontic purposes for treating deep bites [Farha]. Posterior bite splints, with a bilateral distal horizontal plane, are crafted for the lower jaw, often with both halves connected by a metal connector. They are indicated for addressing lower third OCCLUSAL SPLINTS, RETAINERS AND THE RELATION BETWEEN THEM – A REVIEW ARTICLE Dobromira Shopova 1* , Desislava Bakova 2 , Miroslava Yordanova 3 , Svetlana Yordanova 3 1 Department of Prosthetic Dentistry, Faculty of Dental Medicine, Medical University-Plovdiv, Bulgaria e-mail: dent.shopova@gmail.com 2 Department of Health Care Management, Faculty of Public Health, Medical University-Plovdiv, Bulgaria, e-mail: desislavabakova@abv.bg 3 Department of Orthodontics, Faculty of Dental Medicine, Medical University-Plovdiv, Bulgaria e-mail: mirajord@gmail.com; svetlaj@gmail.com Abstract: This article reviews different types of occlusal splints and retainers, and current trends of their creation by digital technologies. They were systematically searched by key words, single or combined. The key words were: bruxism, retainer, modifcation of occlusal splints, modifcation of retainers, 3D printing, CAD/CAM. It was used peer-reviewed articles published in Google scholar until July 2023. The articles were in English with available at least abstract with clear conclusion part. Paid for the reader articles are not included in the review. In this article are presented main and additional types of occlusal splints, different types of retainers and their modifcations, the contact point between splints and retainers and their digital creation. Keywords: Occlusal splints, retainers, digital technologies, CAD/CAM technology, 3D printing. Field: Medical Sciences and Health © 2023 by the authors. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). * Corresponding author: dent.shopova@gmail.com