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Cell adhesion molecules can predict liver hepatocellular carcinoma (LIHC) metastasis and determine prognosis, while the mechanism of the role of cell adhesion molecules in LIHC needs to be further explored. LIHC-related expression data were sourced from The Cancer Genome Atlas (TCGA) and the gene expression omnibus (GEO) databases, and genes related to cell adhesion were sourced from the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. First, the TCGA-LIHC dataset was clustered by the nonnegative matrix factorization (NMF) algorithm to find different subtypes of LIHC. Then the difference of prognosis and immune microenvironment between patients of different subtypes was evaluated. In addition, a prognostic risk model was obtained by least shrinkage and selection operator (LASSO) and Cox analysis, while a nomogram was drawn. Furthermore, functional enrichment analysis between high and low risk groups was conducted. Finally, the expressions of model genes were explored by quantitative real-time polymerase chain reaction (qRT-PCR). The 371 LIHC patients were classified into four subtypes by NMF clustering, and survival analysis revealed that disease-free survival (DFS) of these four subtypes were clearly different. Cancer-related pathways and immune microenvironment among these four subtypes were dysregulated. Moreover, 58 common differentially expressed genes (DEGs) between four subtypes were identified and were mainly associated with PPAR signaling pathway and amino acid metabolism. Furthermore, a prognostic model consisting of IGSF11, CD8A, ALCAM, CLDN6, JAM2, ITGB7, SDC3, CNTNAP1, and MPZ was built. A nomogram consisting of pathologic T and riskScore was built, and the calibration curve illustrated that the nomogram could better forecast LIHC prognosis. Gene Set Enrichment Analysis (GSEA) demonstrated that DEGs between high and low risk groups were mainly involved in cell cycle. Finally, the qRT-PCR illustrated the expressions of nine model genes between normal and LIHC tissue. A prognostic model consisting of IGSF11, CD8A, ALCAM, CLDN6, JAM2, ITGB7, SDC3, CNTNAP1, and MPZ was obtained, which provides an important reference for the molecular diagnosis of patient prognosis.

Copyright of International Journal of Computerized Dentistry is the property of Quintessence Publishing Company Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of International Journal of Computerized Dentistry is the property of Quintessence Publishing Company Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of International Journal of Computerized Dentistry is the property of Quintessence Publishing Company Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of International Journal of Computerized Dentistry is the property of Quintessence Publishing Company Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of International Journal of Computerized Dentistry is the property of Quintessence Publishing Company Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of International Journal of Computerized Dentistry is the property of Quintessence Publishing Company Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of International Journal of Computerized Dentistry is the property of Quintessence Publishing Company Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Craniomandibular Function is the property of Quintessence Publishing Company Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The present study was performed to compare the increase in maternal serum concentrations of four placental proteins during the first half of 240 normal pregnancies. The proteins were pregnancy-associated plasma protein-A (PAPP-A), human chorionic gonadotrophin (HCG), human placental lactogen (HPL) hormone, and pregnancy-specific beta 1-glycoprotein (PSG), all produced by trophoblast cells. The median increases were observed to be very close to exponential growth curves. Based on simple assumptions, these growth curves could be explained as being solely dependent on the growth of the placenta. The assumptions were that the proteins were produced in the placenta at a constant rate per gram of placental cell mass and secreted into the circulation shortly after synthesis. Our investigations showed that for two of the proteins, PSG and HPL, the rate constants were, in fact, close to the reported growth rate of the placenta, whereas the PAPP-A production rate constant was significantly higher than those of the others. The production curve for HCG was very different from that of the other proteins. PAPP-A and HCG must therefore have more complicated mechanisms for regulating the production. An equation was constructed that permitted estimation of the molar production of the placental proteins per gram of placental cell mass per day during the first half of normal pregnancy. The value was highest for HPL and lowest for PAPP-A. [ABSTRACT FROM AUTHOR]

Eleven women with small unruptured tubai pregnancies were treated by laparoscopically guided injection of prostaglandin F2α in the oviduct and in the ovary which contained the corpus luteum. They had no side effects of the treatment and were discharged from hospital 1–3 days later. In 10 women the serum concentration of human chorionic gonadotrophin (HCG) decreased to <20 IU/1 in a median time of 7.5 days, the range being 1–46 days. One woman required an operation 6 days after the treatment as her serum HCG level was stationary and she continued to have abdominal pain. Hysterosalpingography 3 months after the treatment showed patency of the oviduct on the side of the pregnancy in seven of the eight women who have been examined. We conclude that the injection of prostaglandin F2aα seems to promote the resolution of selected tubai pregnancies. [ABSTRACT FROM PUBLISHER]

Background: It is still discussed whether occlusal wear (OW) affects the formation of non-carious cervical lesions (NCCLs)., Objective: To estimate effects of OW on the presence and development of NCCLs, using 16-year follow-up data from a cohort study., Methods: Occlusal and cervical defects were measured in 728 cast models (one from the upper jaw and one from the lower jaw) of 364 participants. Adjusted mixed-effects ordinal logistic models analysing estimated cross-sectional (N = 1308 teeth/291 subjects) and longitudinal (N = 718 teeth/226 subjects) associations of OW with NCCLs using tooth level data., Results: OW size was cross-sectionally (OR = 1.74; 95% CI: 1.27-2.38 for OW size; OR = 0.97; 95% CI: 0.94-0.99 for squared OW size), but not longitudinally (OR = 1.14; 95% CI: 0.99-1.30) associated with odds of higher NCCL sizes. For cross-sectional analyses, predicted probabilities of an NCCL size of 0 decreased from about 0.996 to 0.010 for OW sizes of 0 to 25., Conclusion: Results suggest an association between OW and NCCL size. However, as longitudinal results were non-significant, while consistent in direction, large-scaled cohort studies are demanded to more precisely estimate effect strength., (© 2024 The Authors. Journal of Oral Rehabilitation published by John Wiley & Sons Ltd.)

Aim: The aim of our investigations is to optimize the anatomical basis for the design of a sufficient occlusal relationship, especially in view of the innovative technologies by analyzing the occlusal contact point patterns at cusp structures according to A-, B-, C- localization tooth by tooth on the individual occlusal surfaces in the posterior region in static habitual occlusal position., Materials and Methods: In 3300 subjects of the population-based Study of Health in Pomerania (SHIP 1) the interocclusal registration in habitual intercuspation using silicone registration was used and analyzed by using the special evaluation software Greifswald Digital Analyzing System (GEDAS II). Chi square test was used to investigate whether the distribution of contact areas differed in the group of premolars or molars - each considered separately for maxilla and mandible - on the basis of the probability of error p < 0.05., Results: In 709 subjects (446 male with a mean age of 48.9 ± 13.04 years; 283 female with a mean age of 52.4 ± 14.23 years) the antagonistic situation was specifically considered on natural posterior teeth without conservative or restorative-prosthetic interventions, i.e. without caries, fillings, crowns or other restorations. On the basis of these subjects, the silicone registrations were analyzed using GEDAS II. For the first and second upper molars, the ABC contact distribution was the most frequent: 20.4 % for the first and 15.3 % for the second molar. The second most frequent contact area for maxillary molars was area 0. The upper molars had contact areas only at the maxillary palatal cusp (B-/C-contacts). This contact relationship was most frequent in the maxillary premolar (18.1-18.6 %). In mandibular premolars, with the buccal cusps areas A and B were frequently involved (15.4-16.7 %). Mandibular molars showed a frequent contact pattern involving all A-, B-, C- and 0- contact areas (13.3-24.2 %). To capture the possible influence of the antagonistic dentition situation, the antagonistic situation was specifically considered and except for the mandibular premolars (p < 0.05) the contact distribution did not differ for molars and maxillary premolars regarding the dental status of the antagonistic teeth. Natural posterior teeth without occlusal contacts were observed from 20.0 % in the second lower molars to 9.7 % in the first upper molars., Conclusion: Our results suggest a clinically relevant due to the fact, that this study is the first population-based epidemiological study to analyze the occlusal contact point patterns at cusp structures according to A-, B-, C- localization tooth by tooth on the individual occlusal surfaces in the posterior region in static habitual occlusal position in order to optimize the anatomical basis for the design of a sufficient occlusal relationship., Competing Interests: Declaration of Competing Interest All authors have read and approved the final version of this manuscript, and declare no conflict of interest in the making or publishing of this paper., (Copyright © 2023 Elsevier GmbH. All rights reserved.)

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. 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). 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. On average (median), the premolars had two occlusal contacts each, the posterior teeth had four to five, and tooth 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 affected. 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. 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.

Aim: The present prospective clinical study aimed to validate the Greifswald Digital Analyzing System (GEDAS) as a method for digital assessment of the occlusion in primary and mixed dentition., Materials and Methods: The reproducibility of GEDAS in primary and mixed dentition was assessed using the intraclass correlation coefficient (ICC). In addition, the acceptability of the method to the dentist, the child, and the parent/caregiver was assessed using a modified visual analog scale of faces, the Frankl behavior scale, and the 10-point Likert scale. In total, 20 participants aged between 3 and 9 years (mean age: 6; standard deviation: ± 1.74) with primary (n = 10) and mixed (n = 10) dentition were recruited., Results: The ICC for the number of contact points in all teeth was 0.94 and for the area of contact points was 0.97, indicating good to excellent reproducibility. The average total number of contacts per bite registration per arch in the primary and mixed dentition was 36.5 (17 to 66) and 37.9 (9 to 74), respectively. The average of the total area of interocclusal contact area in the primary and mixed dentition was 25.55 mm2 (5.39 to 70.20) and 29.59 mm2 (2.80 to 78.53), respectively. During the procedure, the majority of dentists reported the child's behavior to be positive (85%) and found the procedure easy to perform (80%), short (6.0 min), and tolerable (80%)., Conclusion: GEDAS is an occlusal analysis tool with good acceptability and reproducibility in children and could be considered for the planning and assessment of restorative and orthodontic treatment in the intermediate stages.

A hands-on method for instrument-based occlusal analysis with digital technology is presented using a patient case example. The method is based on new software for digital occlusal analysis that includes a new measuring system for recording mandibular function (Jaw Motion Analyser Optic System/oJMA). With the new system, occlusal contact patterns in the real movement function of the mandible are captured and analyzed digitally with regard to occlusal interferences or a suitable therapeutic position of the mandible. For this purpose, scans of both jaws are brought together with the movement recordings by means of a special coupling tray and then visualized together as one complete image. Since the movement paths of the temporomandibular joints (TMJs) are also captured, the new system makes it possible to define a suitable therapeutic position specifically aimed at relieving the TMJs, and a therapeutic change in the jaw relation can be adjusted, for instance, by using an occlusal splint. Dedicated software modules provide a layer-by-layer analysis of the intercuspation relationship and the generation of 'envelopes' for occlusal gliding movements. This system is used to gain a deeper and more comprehensive understanding of the relationship between the structure and function of the occlusion. Interfaces to CAD software have also been established.

When recording condylar movement paths with the aid of electronic measuring systems, it is often found that, especially in jaw opening and closing movements, excursive and incursive paths of movement are not congruent but run separately, independently of one another to a greater or lesser degree. The objective of the study was to investigate this phenomenon in the context of rotation vs translation behavior, also taking into consideration additional side-specific condylar movement patterns. For this purpose, the electronic movement records of habitual jaw opening of 259 participants of the associated project of the population-representative basic study SHIP 0 were evaluated. The condylar movement path (condylar tracing, ConTrac) at the arbitrary axis point, the excursion vs incursion behavior in the condylar tracing grid (ExInGrid), and the rotation vs translation behavior (RotTrans) were classified, and the translational condylar path and the maximum angle of rotation were determined metrically. Relationships between the parameters ConTrac, ExInGrid, and RotTrans were statistically analyzed using cross tabulations and Spearman's correlation coefficient. Only about 18% of ConTrac showed congruence of excursive and incursive movement path components, while 39% demonstrated noncongruent paths, and 43% showed further conspicuous features in the movement path. For the parameter ExInGrid, recognizable to highly pronounced loop formation patterns to a degree of 89% were observed in the condylar tracing grid. An average of 12.5 mm (min 2.1 mm, max 21.7 mm) was determined for the purely translational component of the condylar movement path, and 32.1 degrees (min 12 degrees, max 45 degrees) for the maximum angle of rotation. Concerning the rotation vs translation behavior, the linear basic pattern occurred at around 9%; the sigmoidal pattern at 28%; and the hysteretic, loopy or irregular pattern at 63%. The parameters RotTrans and ExInGrid showed a strong correlation, whereas the strength of the correlation for ConTrac and ExInGrid or RotTrans and ConTrac was evaluated as weak or very weak. The rotation vs translation behavior influences condylar movement paths in the positional relationship of excursive and incursive components. The visualization of several condylar movement paths in the form of a condylar tracing grid helps to capture complex rotational and translational motion components of the real condyles more effectively than the assessment of a single condylar movement path.

The articulation parameters, especially the horizontal condylar inclination angle (HCI), the Bennett angle (BA), and the immediate side shift (ISS) were determined in 259 subjects (100 males; 159 females) of the associated project with reference to the population-representative baseline study (Study of Health in Pomerania, SHIP 0). The evaluations were based on a clinical functional status and electronic motion recording with the ultrasonic measuring system Jaw Motion Analyser (JMA, Zebris, Isny, Germany). The reference plane, to which all measured values were represented and the HCI calculated, was the hinge axis infraorbital plane (HA-IOP). The HCI was determined after an excursive movement with a length of 4 mm to the HA-IOP in the sagittal view and the BA after a mediotrusive excursion movement of 6 mm in the horizontal view to the midsagittal plane. For the standard and limit values, the average value in addition to the standard deviation and the 10th and 90th percentile value (10th percentile value, 90th percentile value) were determined: HCI right 52.1 ± 10.14 degrees (39.4 degrees, 64.0 degrees), HCI left 53.1 ± 9.67 degrees (42.3 degrees, 67.0 degrees), BA right 15.2 ± 7.53 degrees (6.7 degrees, 25.0 degrees), BA left 14.2 ± 7.84 degrees (5.4 degrees, 24.1 degrees). The HCI was approximately 2 to 3 degrees larger in females (males: right 50.5 ± 9.47 degrees, left 51.9 ± 8.99 degrees; females: right 53.1 ± 10.42 degrees, left 53.8 ± 10.03 degrees). Likewise, the BA in the age group ≥ 40 years (males: right 14.4 ± 6.62 degrees, left 13.1 ± 7.14 degrees; females: right 17.0 ± 9.02 degrees, left 16.9 ± 8.72 degrees). The latter proved to be statistically significant in the t test for independent samples, assuming variance equivalence on the right, with P = 0.009, and with rejection of the variant equivalence on the left, with P = 0.002. The right and left HCI and BA joint values showed highly significant linear dependence at P < 0.001, but rather low, however, for the HCI with r2 = 0.175 for the HCI and r2 = 0.228 for the BA. In 46% of cases, the right and left HCI values differed up to 5 degrees only; a further 20.9% were in an interval difference of between 5 and 10 degrees. The following results were shown for the differences in the BA: 56.4% of the cases were between 0 and 5 degrees, and 26.2% were in the interval ranges of 5 to 10 degrees. ISS occurred in 18.1% of cases on the right side of the joint, and in 27.8% of cases on the left side. On both sides of the joint it was significantly more frequent in the age group ≥ 40 years with assumed variance equality than in the age group < 40 years (P = 0.002 right, P = 0.003 left). The groups relating to the Helkimo index (HI) did not differ significantly in all function-specific parameters. If it is assumed that there is no significant influence on the occlusion if the HCI values differ by 7 to 8 degrees from the average value, only approximately one third of all cases (35.1%) were characterized by a purely average value setting in the articulator. In 41.7% of cases, one joint value was situated outside the average value range; in 23.2% of the cases both values were outside the average value range. Without a measurement of the condylar path inclination, however, it is impossible to decide to what extent the HCI deviates from the average value, and which joint side is larger or smaller than the other and to what extent. These results suggest that in extensive and complex cases, the articulator should be adjusted according to individual, function-specific joint values.

Objectives: In a double-blinded randomized controlled clinical trial, the impact of face-bow registration for remounting complete dentures (CDs) on the occlusal parameters (part I) was evaluated., Materials and Methods: New CDs of 32 patients were duplicated and mounted after intraoral pin registration according to mean settings (group 1) and (group 2) using a face-bow (arbitrary hinge axis). The vertical dimension was reduced to the first occlusal contact point, and a bite record was fabricated in the articulator. The number of contacts and the number of teeth in contact were evaluated by a computer program (laboratory result). After randomization, half of the CDs were adjusted according to protocol of group 1 and group 2 and delivered to the patients. After 3 days (T1) and 84 days (T2), clinical static contact points and teeth in contact were counted. Contact points and teeth in contact of both groups (laboratory results) and at different moments (clinical results) were analyzed statistically with the F test and bootstrapping., Results: Laboratory: No. 2 (face-bow) showed more occlusal contact points than no. 1 (mean setting), p > 0.05. The number of teeth with at least one occlusal contact was significantly higher in no. 2 (p = 0.027). Clinic: The mean number of teeth with at least one clinical contact point was significantly higher in no. 1 (no. 1 = 7.13, no. 2 = 5.31; p = 0.042). Extent of the vertical shift poorly correlated with number of laboratory occlusal contact points (R 2  = 0.017)., Conclusions: Considering the complex multistep study design, a limited number of participants, and referring to one specific arbitrary face-bow, the following conclusion could be drawn: no substantial difference by the use of the arbitrary face-bow compared to a mean setting could be determined, when changing the vertical dimension in the articulator within a remounting procedure of complete dentures., Clinical Relevance: Further research is necessary to determine the effects of different arbitrary face-bows on the fabrication and adaptation of removable dentures.

Introduction: The decision to consolidate European higher education was reached by the Bologna Conference. Based on the Anglo-American system, a two-cycle degree program (Bachelor and Master) has been introduced. Subjects culminating in a state examination, such as Medicine and Dentistry, were excluded from this reform. Since the state examination is already comparable in its caliber to a Master's degree in Medicine or Dentistry, only advanced Master's degree programs with post-graduate specializations come into consideration for these subjects. In the field of dentistry numerous post-graduate study programs are increasingly coming into existence. Many different models and approaches are being pursued., Method: Since the 2004-2005 winter semester, the University of Greifswald has offered the Master's degree program in Dental Functional Analysis and Therapy. Two and a half years in duration, this program is structured to allow program participation while working and targets licensed dentists who wish to attain certified skills for the future in state-of-the-art functional analysis and therapy., Aim: The design of this post-graduate program and the initial results of the evaluation by alumni are presented here., Conclusion: Our experiences show that the conceptual idea of an advanced Master's program has proved successful. The program covers a specialty which leads to increased confidence in handling challenging patient cases. The sharing of experiences among colleagues was evaluated as being especially important.

Diagnostic imaging and jaw motion tracking are among the most important technologies used to document and assess the functional status of the stomatognathic system and to plan complex prosthetic restorations. However, the two technologies have not been used together until now. This article introduces SICAT Function (SICAT, Bonn, Germany), a new software application that directly combines and merges three-dimensional cone beam computed tomography (CBCT) and electronic jaw motion tracking (JMT) data. The software can also import digital impressions acquired with intraoral scanners and integrate them in functional movement displays. The result is an anatomically precise yet real-dynamic rendering of jaw movement, ready for comprehensive evaluation and analysis. Moreover, changes in the joint space (gap between the condyle and mandibular fossa) at defined mandibular resting positions or during mandibular movements can be directly measured and displayed. Only one CBCT scan is needed for patient-specific assessment of condylar positions (centric and therapeutic), which are displayed together with the joint space. All other positions are derived via correlation with electronic measurements.

Occlusal performance is a substantial determinant of the quality of dental prosthetic restorations. In the follow-up (SHIP 1) to the Study of Health in Pomerania (SHIP), a representative population of 3300 subjects was studied in the first exploratory evaluation of the occlusion of artificial teeth in the chewing center (first molar region) of partial dentures. A digital analysis of interocclusal records of habitual intercuspation position (ICP) was performed using the Greifswald Digital Analyzing System (GEDAS), a software package that identifies contact points as transparent areas. 562 subjects (280 men aged 61.7 ± 11.9 years and 282 women aged 60.7 ± 10.7 years) had maxillary removable partial dentures (RPDs), and 619 (271 men aged 65.0 ± 11.5 years and 348 women aged 62.4 ± 10.6 years) had mandibular RPDs. Most RPDs were retained with either attachment retainers (11.7% maxilla, 11.7% mandible), cast clasps (38.4% maxilla, 40.7% mandible), telescopes with double crowns (15.7% maxilla, 19.1% mandible), or wrought wire clasps (16.4% maxilla, 8.2% mandible). Some had a combination of different retention elements. The mean number of artificial teeth was 7.8 ± 2.9 in the maxilla and 7.5 ± 3.0 in the mandible. Only the artificial teeth (first molars) in mandibular partial dentures showed differences in the frequency of occlusal contacts between groups (chi-square test). Of these, telescopic crown-retained RPDs had the highest frequency of occlusal contacts (74.4% at tooth 36 and 77.1% at tooth 46), and wrought wire-retained RPDs had the lowest (48.4% at tooth 36 and 45.2% at tooth 46). The results for RPDs with a free-end saddle were comparable and analogous; contact frequencies for those with an interdental saddle did not differ significantly. Notably, the overall frequency of occlusal contacts was greater for tooth 46 (62.9%) than for tooth 36. In conclusion, when replacing teeth in the chewing center, particularly in the mandible, telescopic crown-retained RPDs offer a distinct advantage in terms of occlusal contacts and thus provide better occlusal stability.

We are currently developing new software for simultaneous visualisation and analysis of computerized recorded masticatory function and masticatory muscle activity. With the software, motion data recorded using the Jaw Motion Analyser and EMG data on masseter muscle activity can be uploaded in order to evaluate chewing activity immediately proximal to the occlusal surfaces. The software successfully differentiated between jaw opening and closing movements and filtered out muscle activity peaks, which were graphically depicted in the respective movement trajectories. This tracking strategy made it possible to visualize the movement sectors where chewing forces were effective and to estimate the strength of these forces. In the future, this software should improve our ability to analyze and assess the development of chewing forces. Therefore, it could provide a tool for optimal planning of implant-supported or CAD/CAM restorations.

Virtual articulation makes it possible to overcome the limitations of mechanical articulation. Novel visualization techniques have great advantages. In this study, the occlusal surfaces of the upper and lower teeth were digitized with a 3D scanner, and real functional movements of the mandible were recorded using the Jaw Motion Analyzer (JMA), an ultrasonic measurement system. A coupling component designed for clinical use in the patient's mouth was utilized for precise referencing of the movement and scan data. Similar to a two-sided impression tray, the coupling tray is used to take a joint impression of the upper and lower arches. The JMA records the positions of the mandible and the coupling component in space. The virtual articulator was designed for visualization of jaw relationships during mastication. For analysis of intercuspation, the system generates dynamic images on which closing movements/ dynamic occlusion and contact areas are highlighted. The jaw movement data are plotted to create an envelope surface representing the maximum possible space occupied by the mandible. Such an envelope surface is a type of virtual FGP (functionally generated path) bite registration. It can be applied to design virtual tooth restorations and helps to quantify the occlusal space in a virtual environment. This system can be used to individually register and utilize the variability of occlusal function.

The following article describes a method for the clinical depiction and documentation of the strength, extent, and location of occlusal contact areas on the basis of digitized bite records. Bite records made of low-viscosity, addition-cured silicone in centric occlusion are digitized in a document scanner using incident and transmitted light scanning. Layer thicknesses < 20 microm were interpreted as occlusal contacts and classified as belonging to the anatomical structures of the occlusal surfaces. This procedure is of particular significance for epidemiological studies, but also of interest for dental practices and laboratories, since it can be used as a simple method of continuous quality control, documentation, and archiving of the patient's current occlusal contact situation.

Visualization of the dynamic occlusion is one of the central tasks in both clinical dentistry and dental engineering. Many aspects of dynamic occlusion, such as the interocclusal function in the posterior region, cannot be seen directly clinically and at best can be recorded with contact paper. Therefore, analyses of the dynamic occlusion using mounted models in the articulator are unavoidable in many cases for reproduction of dynamic occlusion. However, the reproduction of dynamic occlusion in the mechanical articulator has clear restrictions inherent to the process, but also caused by biological variability. Virtual articulators can expediently supplement mechanical articulators, since with them it is possible to display in relation to time unusual and extraordinary perspectives, such as sectional images and flowing, sliding contact points. One of the latest developments in the field of virtual articulation is the 3D virtual articulation system module of the Zebris company, D-Isny. By means of a specially developed coupling tray, 3D-scanned rows of teeth can be matched with computerized motion recordings of mandibular function. The software displays the movements of the 3D-scanned rows of teeth not only with jaw motion but also with chewing motion--therefore movements under chewing pressure--in real time and facilitates special analytical methods transcending mechanical occlusion analysis in conventional articulators: This includes displays of the strength of the contact points and surfaces, the occurrence of the contact points in relation to time, sectional images of the dentition, analyses of the interocclusal gap in the occlusal region, etc. This software and its possibilities are described and explained by reference to individual cases.