Journal of Craniomandibular Function, 02/2022

Initial therapy with occlusal splints (splints) is a key stage of complex prosthetic rehabilitation due to changes in the vertical dimension of occlusion. Good patient compliance is crucial to the success of treatment. In addition to the desire for minimally invasive treatments, patients have increasingly demanding expectations regarding esthetic and functional outcomes, even in the provisional stages of treatment, which are inadequately met by traditional splints. This requires a shift in thinking in routine clinical practice. If irreversible treatments are required, sufficient initial functional and esthetic testing is needed to increase their predictability. The advent of new dental materials and digital technologies has led to the development of new treatment concepts for prosthetic dentistry. This article presents a case example illustrating dental applications for polycarbonate as a ‘new’ splint fabrication material. The special material properties of polycarbonate enable the manufacture of fully anatomical, tooth-colored splints that closely simulate the final prosthetic restoration. The Munich splint concept takes functional, phonetic, esthetic, and minimal invasiveness expectations into account and is therefore an innovative and flexible pretreatment strategy. Keywords: Munich splint, polycarbonate splint, vertical dimension of occlusion (VDO), splint therapy, reconstruction, erosion

Sufficient occlusion is a basic prerequisite for the functional efficiency of the occlusal surfaces. Exactly where and in what number the occlusal contacts in the posterior region should be present for this purpose is controversial. Aim: The present study investigated the number and location of occlusal contacts on posterior teeth without dental findings, ie, without caries or restorative restorations such as fillings, crowns, etc. Such natural posterior teeth were present in 709 subjects (males [m] = 446: 48.9 ± 13.04 years, females [f] = 283: 52.4 ± 14.23 years) of a subject collective of 1223 subjects (m = 648, f = 575) of the regional baseline study ‘Study of Health in Pomerania 1’ (SHIP-1). Materials and method: Silicone bite registrations in habitual intercuspation (IP) were evaluated, whereby the test persons were asked to fix the bite block with biting force without biting firmly. The registrations were scanned with a document scanner in incident and transmitted light; a calibration strip was used to determine the transparency threshold of a layer thickness of 20 μm, below and equal to which the transparent zone was considered as a contact or contact area. The Greifswald Digital Analyzing System 2 (GEDAS 2) software was used to determine the number and location of occlusal contact areas tooth by tooth. To define the localization of the contacts, a cross with two concentric circles symmetric to the longitudinal fissure was superimposed on the occlusal surface; this resulted in four inner and four outer quadrants. Thus, the number of pixels in occlusal contact areas per inner and outer quadrant could be determined. The image resolution was 300 dpi. Results: On average (median), the premolars had two occlusal contacts each, the posterior teeth had four to five, and Vieltooth 46 had six contacts. The right and left teeth did not differ in the frequency of occlusal contacts in the Mann-Whitney U test for independent samples. In the maxillary premolars, frequent contact areas were primarily located mesially on the inner and outer slopes of the palatal cusp. In the maxillary molars, the palatal slope of the distopalatal cusp and the inner slopes of the mesiopalatal and distopalatal cusps were frequently addressed. On the mandibular premolars, the inner slopes of the buccal cusps and the buccal slope of the distobuccal cusp were particularly frequently addressed; in teeth 35 and 45, the buccal slope of the mesiobuccal cusp was also somewhat more frequently addressed. Teeth 36 and 46 frequently had contact areas on the buccal slope of the distobuccal cusp as well as on the inner slopes of the distal cusps (distobuccal and distolingual), whereas teeth 37 and 47 tended to behave similarly. Conclusion: Epidemiologically, the focus of the frequent contact areas on the respective supporting cusps of the maxillary and mandibular posterior teeth and a distribution of contacts stabilizing the tooth in its position in the dental arch through the interlocking were confirmed. It makes sense to take this into account when designing occlusal surfaces in the posterior region. Keywords: occlusion, occlusal contacts, posterior teeth, epidemiology

A digital workflow was used to fabricate complete dentures with different concepts of occlusion for a 65-year-old female patient using the Zirkonzahn digital denture system (Zirkonzahn, Gais, Italy). By using CAD/CAM technology and the related potentials for adjusting occlusal parameters, it was possible to develop dentures with a custom-adapted concept of occlusion based on the individual patient parameters in a time- and cost-efficient manner. After several weeks of trial wear, the patient preferred the complete dentures with sequential guidance in laterotrusion (with canine/premolar dominance) and 15-degree cusp angles due to better wearing comfort and masticatory performance. In summary, the digital workflow presented in the present article integrated important aspects of the patient’s dental history and enabled the creation of an occlusal concept individually adapted to her masticatory system. Keywords: digital complete dentures, computer-aided design and manufacturing, CAD/CAM, bilateral balanced occlusion, sequential group function occlusion, mastication, patient comfort