Rapid developments in digital dentistry, such as digital workflows and CAD/CAM systems, have led to questions about digital occlusion, including the capabilities of occlusal analysis. There is a need for clear definitions and terminology. What do we mean when we talk about “occlusion” in the context of digitization, especially in the case of digital models? What are the capabilities of digital occlusal analysis? The following article presents our initial thoughts on this important topic, which may be useful in the development of future guideline. Keywords: digital occlusion, digital occlusion analysis, virtual articulator, digital articulator, digital patient, digital functionally generated path technique (FGP technique)

Rapid developments in digital dentistry, such as digital workflows and CAD/CAM systems, have led to questions about digital occlusion, including the capabilities of occlusal analysis. There ist a need for clear definitions and terminology. What do we mean when we talk about “occlusion” in the context of digitization, especially in the case of digital models? What are the capabilities of digital occlusal analysis? The following article presents our initial thoughts on this important topic, which may be useful in the development of future guideline.

Aim: To test four different measurement methods to evaluate deviations between planned and actual implant positions within a digital workflow applying 3D-printed surgical guides. Materials and methods: A fully digital workflow was applied to simulate the single implant insertion to replace a maxillary missing central incisor and first molar in 10 gypsum casts (n = 10). Surgical guides (n = 10 per site) were printed by digital light processing for implant bed preparation and implant insertion. Four methods were used to analyze 3D deviations between the planned (target) and achieved implant positions: Methods 1 and 2 used an automated computer program (ACP) to assess deviations between the initial planning file and a file that represented the actual implant position either by the implant bed [ACP_BED] or by the inserted implant [ACP_IMP]. For Method 3, a standard tessellation language dataset representing the actual implant position was used and equipped with reference planes. This dataset was registered with the target planning, allowing manual measurements [MAN_MEAS]. Method 4 used a reverse engineering approach based on 3D high-resolution scans [REVERSE]. Results: Mean 3D deviations, including for anterior and posterior implant sites, ranged between 0.26 ± 0.11 mm [REVERSE] and 0.40 ± 0.09 mm [ACP_BED] at the implant shoulder, between 0.52 ± 0.24 mm [REVERSE] and 0.91 ± 0.24 mm [ACP_BED] at the implant apex, and between 1.68 and 2.35 degrees in angular deviation. Implant sites did not differ significantly, while some of the evaluation methods differed for shoulder and apex. Conclusion: [REVERSE] revealed the smallest deviations between planned and actual implant position. 3D implant deviations were comparable with findings in the literature or even lower. Keywords: digital light processing (DLP), 3D printing, static computer-aided implant surgery (s-CAIS), implant surgical guides, accuracy, trueness, evaluation methods

An increasing number of accuracy studies on 3D digitizing systems, especially intraoral scanning devices, are being published in scientific and educational journals. The methods, measurement values, and statistical parameters of these studies vary. Certain inconsistencies exist, which lead to difficulty in terms of interpretation and sometimes even questionable conclusions being drawn. These issues make it almost impossible to compare the results of such studies. One aspect inherent in this is the mutable use of basic terms describing the quality of measurement outcomes. A clear definition of such terms and clear instructions as to their respective calculation processes is essential for communication among scientists as well as for reporting measurement results to the dental community. Therefore, the aim of the present guideline is to provide a clear definition of the accuracy, trueness, and precision as the basic terms in the context of digital dentistry. The survey for this guideline included the application of ISO Norms and their expansion to special aspects concerning 3D data acquisition and, in particular, surface meshes. Additionally, the literature was screened to collect approaches, which can be seen as useful for dealing with these terms when performing different kinds of studies. Keywords: intraoral scanning, accuracy, precision, trueness, ISO standard, 3D evaluation

Das Ziel dieser Studie bestand in der Evaluation der klinischen Qualität und Langzeitstabilität von chairside-hergestellten Lithiumdisilikatkeramikkronen nach 10 Jahren. Keywords: Digitalisierung, Langlebigkeit, Vollkeramik, monolithische Kronen

The present application report describes a cast-free and chairside workflow that enables the manufacturing of monolithic restorations on custom-made abutments without damaging the periimplant soft tissue for impression taking. An easily achievable checklist for the individualization of standard abutments is presented so that the shape of the abutment is compatible with especially developed software after optical impressions. The principle of the method contains an extraoral impression of the finish line of the abutment and an intraoral impression that indicates the abutment position in relation to the adjacent teeth. The software needed for the semi-automated registration of the intra- and extraoral impression operates with .stl data and can be provided by the corresponding author on request. Keywords: customized abutments, chairside, cast-free, registration, intraoral, scanner, software, finish line

An entirely digital concept has previously been proposed for the reconstruction of the occlusal plane in the case of wear-induced loss of the vertical dimension of occlusion (VDO). The concept, however, calls for a face scan. Since this technology is less frequently available than a facebow, the concept discussed in this article proposes a combination of analog and digital techniques. It takes into account the problem of redefining the occlusal plane in the case of occlusal alteration, and tries to avoid a situation where the chairside digital design of the occlusal surfaces is performed without any anatomical references. Such a situation poses a significant risk if the treatment indication for bite elevation exists in both the maxilla and the mandible. Keywords: vertical relation, bite raising, chairside, CAD/CAM, planes, facebow, alternating, ceramic, composite

Aim: The aim of this in vivo study was to measure antagonist wear caused by polished monolithic posterior zirconia crowns over a 24-month period using the intraoral digital impression (IDI) technique. Materials and methods: Thirteen zirconia crowns were placed in nine patients. The crowns and adjacent teeth were captured using an intraoral scanner (Lava C.O.S.). The corresponding antagonist teeth and the respective neighboring teeth were also scanned. Scanning was performed immediately after the restoration (baseline) as well as 12 and 24 months after crown placement. Geomagic Qualify software was used to superimpose the follow-up data sets onto the corresponding baseline data set, identify wear sites, and measure maximum vertical height loss in each individual wear site. Overall antagonist wear was then determined as the mean of wear rates measured in all of the individual antagonist units. In addition, wear rates in enamel and ceramic antagonists were analyzed as part of the scope of this study. Results: The maximum mean wear with standard deviation (SD) in the overall sample with a total of nine patients, 13 antagonist units, and 98 evaluable wear sites was 86 ± 23 µm at 12 months, and 103 ± 39 µm at 24 months. The maximum mean wear in the enamel antagonist subgroup was 87 ± 41 µm at 12 months, and 115 ± 71 µm at 24 months; and in the ceramic antagonist subgroup 107 ± 22 µm at 12 months, and 120 ± 27 µm at 24 months. Conclusions: The wear rates determined in this study are comparable to those of existing studies. The IDI technique of wear analysis can be carried out in a practical manner and produces useful results. Keywords: wear, zirconia, monolithic, antagonist, clinical, digital, intraoral scan