Impact of Home-Based Work during the COVID-19 Pandemic on Mental and Physical Health in a German Population-Based Sample.

Background: The COVID-19 outbreak necessitated physical distancing, as part of secondary prevention, at a personal and professional level. Working from home (WFH) became increasingly important. In this study, the impact of the COVID-19 pandemic restrictions on physical and mental health is investigated, compared with pre-pandemic data, and with employees who WFH and are on-site. Methods: Data from the German Saxon longitudinal study population were used. Attitudes towards WFH as well as mental and physical health assessments during the COVID-19 pandemic were examined. Comparisons were made with corresponding pre-pandemic scores and between employees WFH and on-site in 2022. Results: In total, 319 participants with equal gender distribution were included. Of those, 86 worked from home stating better organizability of their work, more time for partnership, less stress, and greater work satisfaction. Compared to pre-pandemic data, the D-score, PHQ-4, G-Score, and PHQ-SSS-8 showed a significant increase. No difference in physical or mental health between employees WFH and on-site was observed. Conclusion: In general, COVID-19 restrictions had a negative impact on mental and physical health. Although WFH is well accepted, it did not show significant health benefits.

[Anxiety, Depression, Psychological Strain and Physical Complaints before and after the Covid-19 Pandemic in a German Longitudinal Study with Adults from Saxony]. / Ängstlichkeit, Depressivität, psychische Belastung und Körperbeschwerden vor und nach der Covid-19-Pandemie in einer deutschen Längsschnittstudie bei Erwachsenen aus Sachsen.

OBJECTIVE: The objective of the study was to investigate whether psychological distress increased in a German community sample from Saxony during the course of the Corona pandemic. METHODS: In 2017/2018 and 2022, N=289 participants (54.7% female) of the Saxon Longitudinal Study were interviewed about their psychological well-being using questionnaires (PHQ-4, SSS-8). RESULTS: There is a significant increase in complaints (anxiety, depression, psychological distress, physical complaints) compared to 2017/2018 to 2022 with effect sizes in the small and medium range (Cohens d=0.26-0.62). CONCLUSION: Data collection was not due to the pandemic but was routine as part of an ongoing long-term study. The Covid-19 pandemic led to an increase in psychological distress and physical complaints in a Saxonian, age-homogeneous population sample.

Psychological and Socio-Economical Determinants of Health: The Case of Inner German Migration.

A substantial body of research has shown worse health conditions for East- vs. West-Germany in the wake of reunification. In the present study, we investigate how these differences between the two formerly divided regions developed and what maintains them. Specifically, we consider the associations between health status, income satisfaction, and health-related locus of control. In a quasi-experimental and longitudinal study design, we are particularly interested in the differences between individuals who stayed in East-Germany and those who were born in the East but migrated to West-Germany. To this end, we examined data from seven waves of the Saxony Longitudinal Study (2003-2009). Specifically, we tested a cross-lagged panel model with random effects, which evinced very good model fit. Most parameters and processes were equivalent between individuals who stayed in East-Germany vs. moved to West-Germany. Crucially, there was the expected pattern of positive correlations between health, income, and locus of control. In addition, we found substantially lower values for all three of these variables for the individuals who stayed in East-Germany (vs. moved to West-Germany). A possible explanation is the increase in socio-economic status that the internal migrants experienced. These findings present an important contribution of research in order to foster a better understanding on the social dynamics in Germany related to internal/domestic migrants and implications in the context of health outcomes (e.g., significantly more unemployment in East vs. West-Germany), especially since almost 20-25% of East-German citizens migrated to West-Germany. Until now, there are no similar studies to the Saxony longitudinal project, since the data collection started in 1987 and almost every year an identical panel has been surveyed; which can be particularly useful for health authorities. The study mainly focuses on social science research and deals with the phenomenon of reunification, approaching several subjects such as mental and physical health, quality of life and the evaluation of the political system. Yet even though many people have experienced such a migration process, there has been little research on the subjects we approach. With our research we deepen the understanding of the health consequences of internal migration.

The long-lasting impact of unemployment on life satisfaction: results of a longitudinal study over 20 years in East Germany.

BACKGROUND: Economic disruption in East Germany at the time of reunification (1990) resulted in a noticeable increase in unemployment. The present study provides data from a German cohort for over 20 years. The aim was to examine how the frequency of experiencing unemployment affects life satisfaction and whether their relationship changes over time. METHODS: In the Saxon Longitudinal Study, an age-homogeneous sample was surveyed annually from 1987 to 2016. Since 1996, 355 people (54% female) have been examined for issues related to unemployment. Life satisfaction was measured with both the Global Satisfaction with Life Scale and the Questions on Life SatisfactionModules questionnaire. RESULTS: In 1996, the participants were 23 years old and 50% of the sample was affected by unemployment. At all 16 different measuring points, participants who were never unemployed indicated higher life satisfaction than those who were once unemployed. The repeatedly unemployed consistently reported the lowest values of life satisfaction. In each year, there were significant differences with small to medium effect sizes. CONCLUSION: Our results support the notion that the adverse effects of unemployment on life satisfaction increase with the time spent unemployed. In 2016, only 2% of the cohort were currently unemployed, but differences between people with and without unemployment experience still exist. This indicates that the negative effect of the unemployment experience will last for a very long time. To the best of our knowledge, this is the first study that demonstrates the effect so persistently at so many measurement points for over 20 years.

High-resolution MR imaging for dental impressions: a feasibility study.

OBJECTIVES: Magnetic resonance imaging is an emerging technology in dental medicine. While low-resolution MRI has especially provided means to examine the temporomandibular joint due to its anatomic inaccessibility, it was the goal of this study to assess whether high-resolution MRI is capable of delivering a dataset sufficiently precise enough to serve as digital impression of human teeth. MATERIALS AND METHODS: An informed and consenting patient in need of dental restoration with fixed partial dentures was chosen as subject. Two prepared teeth were measured using MRI and the dataset subjected to mathematical processing before Fourier transformation. After reconstruction, a 3D file was generated which was fed into an existing industry standard CAD/CAM process. RESULTS: A framework for a fixed dental prosthesis was digitally modeled and manufactured by laser-sintering. The fit in situ was found to be acceptable by current clinical standards, which allowed permanent placement of the fixed prosthesis. CONCLUSIONS: Using a clinical whole-body MR scanner with the addition of custom add-on hardware, contrast enhancement, and data post-processing, resolution and signal-to-noise ratio were sufficiently achieved to allow fabrication of a dental restoration in an acquisition time comparable to the setting time of common dental impression materials. Furthermore, the measurement was well tolerated. CLINICAL RELEVANCE: The herein described method can be regarded as proof of principle that MRI is a promising option for digital impressions when fixed partial dentures are required.

High isotropic resolution magnetic resonance imaging of the mandibular canal at 1.5 T: a comparison of gradient and spin echo sequences.

OBJECTIVES: The precision of localizing the mandibular canal prior to surgical intervention depends on the achievable resolution, whereas identification of the nerve depends on the image contrast. In our study, we developed new protocols based on gradient and spin echo sequences. The results from both sequences were quantitatively compared for their agreement to identify the most suitable approach. METHODS: By limiting the field of view to one side of the mandible, three-dimensional acquisitions with T1 weighted gradient and spin echo sequences were performed with 0.5 × 0.5 × 0.5 mm3 resolution within 6.5 min covering the mandibular canal from the mandibular to the mental foramen. Aliasing artefacts were suppressed by different techniques. A manual segmentation of the mandibular canal from seven healthy volunteers was performed on this section by three different observers. The surface distance of the segmented volumes was computed between both sequences as well as between the different observers as a measure of equality. RESULTS: The quantitative comparison of the segmentation resulted in an average surface distance of 0.26 ± 0.05 mm between both sequences and an interobserver difference of 0.26 ± 0.08 mm for gradient and 0.29 ± 0.07 mm for spin echo data. By repeated evaluation, a difference of 0.15 ± 0.02 mm for gradient and 0.18 ± 0.03 mm for spin echo data was observed, indicating a slightly higher variability for spin echo images. CONCLUSIONS: Both sequences can be used to achieve high-resolution images with good contrast and can be used for precise localization of the mandibular canal. Despite a slightly increased difference for the spin echo data, the advantage of an easy and robust setup remains.

Band alignment and optical absorption in Ga(Sb)N alloys.

We extend the theory of band alignment proposed by Harrison to ternary and quaternary heteropolar semiconductors. Combining this with first-principles density functional theory incorporating the LDA/GGA+U formalism (LDA: local density approximation; GGA: generalized gradient approximation) can result in useful electronic structure predictions for new alloys. The practicality of this is demonstrated by application to the Ga(Sbx)N1-x alloys, where the feasibility of water splitting reaction under visible light irradiation is discussed.

Diagnosis of dental abnormalities in children using 3-dimensional magnetic resonance imaging.

PURPOSE: To assess the feasibility of magnetic resonance imaging (MRI) of dental abnormalities in children. MATERIALS AND METHODS: The study included 16 patients (mean age, 10.8 yr) prospectively selected from 1,500 orthodontic patients. The selected patients included 3 with a mesiodens, 9 with supernumerary teeth other than a mesiodens, 1 with gemination, 1 with dilacerations, 1 with transmigration, and 1 with transposition. Three-dimensional (3D) images were acquired on a 1.5-T MRI scanner using a 3D turbo spin echo pulse sequence with a voxel size of 0.8 × 0.8 × 1 mm. The measurement time was 4 to 5 minutes. RESULTS: Using natural MRI contrast, the teeth, dental pulp, mandibular canal, and cortical bone could be clearly delineated. The position and shape of malformed teeth could be assessed in all 3 spatial dimensions. CONCLUSION: MRI was found to be a well-tolerated imaging modality for the diagnosis of dental abnormalities in children and for orthodontic treatment and surgical planning. Compared with conventional radiography, dental MRI provides the advantage of 3-dimensionality and complete elimination of ionizing radiation, which is particularly relevant for repeated examinations in children.

Measurement of tooth and implant mobility under physiological loading conditions.

In vivo measurement of the mobility of teeth under physiological loading has been subject of research for years. Comparing the deflection under load of dental implants with teeth provides valuable input for designing restorations spanning both teeth and implants. Physiological force rise time of about 50-100 ms and displacement of 10-100 µm requires high spatial and temporal resolution of the measurement set-up. Using an optical system attached to the teeth/implants to be measured and a light source attached to a point of reference, displacement of teeth and implants under axial and lateral loading was measured on a series of volunteers. Axial displacement of teeth shows strong time dependence consistent with (hydraulic) damping not observed for lateral loads. Displacement under lateral loading was found to be about one order of magnitude higher than under axial load. For dental implants elastic deflection was observed in axial and lateral direction without measurable influence of the load rise time. For purely axial loading, dental implants and teeth show similar deflection under physiological force rise time but for lateral loading the considerably difference between teeth and implant may put some restrictions on the construction of tooth-implant-bridges, especially for teeth in the anterior region.

On precise localization of boundaries between extended uniform objects in MRI: tooth imaging as an example.

OBJECT: The purpose of this study was to investigate the achievable precision of localization of boundaries between extended uniform objects in MRI and to study the effect of zero-filling on reaching it. MATERIALS AND METHODS: A theoretical model of an object boundary in the presence of noise was introduced, and the error of localization was derived. The effect of zero-filling on reaching the achievable precision was assessed by computer simulations and experimentally on an extracted tooth in a signal-giving medium. RESULTS: With the help of the theoretical model, the achievable precision of localization of boundaries between two uniform extended objects was shown to surpass the nominal resolution by a factor equal to the contrast-to-noise ratio. In the simulations and phantom experiments, zero-filling followed by image segmentation allowed for approaching the theoretical value. As an application example, an MRI-based dental impression was performed in vivo, and a bridge was produced and permanently fixed to the volunteer's teeth. CONCLUSION: This work demonstrates that in an MRI experiment, the achievable precision of localization of object boundaries is not limited to the nominal resolution and can surpass it by an order of magnitude. Zero-filling is a simple and effective method of reaching it.

High-resolution 3D magnetic resonance imaging and quantification of carious lesions and dental pulp in vivo.

OBJECTIVE: The purpose of the study was to assess the feasibility of MRI of three-dimensional visualization and quantification of carious lesions, as well as measurement of the distance between the lesion and dental pulp in vivo. MATERIALS AND METHODS: High-resolution 3D MRI was performed to measure seven carious lesions in vivo using gelatinous gadolinium-based oral contrast medium in combination with an intraoral radio frequency receiver coil on a clinical 1.5 T MRI scanner. Extension of the carious lesion in three spatial dimensions and the minimum distance between the lesion and dental pulp were quantified. When possible, the result was compared to an X-ray projection and an impression of the lesion taken using a plastic impression material before and after dental treatment. RESULTS: Carious lesions, including pit and fissure, approximal lesions, and occult dentin caries, could be visualized due to the MRI signal rise in the porous affected dentin. The minimum distance between the carious lesion and dental pulp could be determined in all cases. CONCLUSION: The results presented demonstrate the feasibility of high-resolution dental MRI to three-dimensionally visualize and quantify carious lesions, including approximal and occult caries lesions, and measure the minimum distance to the dental pulp.

The effects of recombinant human growth/differentiation factor-5 (rhGDF-5) on bone regeneration around titanium dental implants in barrier membrane-protected defects: a pilot study in the mandible of beagle dogs.

PURPOSE: This dog study sought to evaluate guided bone regeneration (GBR) in peri-implant defects following implantation of beta-tricalcium phosphate (beta-TCP) with and without osteoinductive recombinant human growth/differentiation factor-5 (rhGDF-5). MATERIALS AND METHODS: In five beagle dogs, all mandibular premolars and the first molar were extracted. After 2 months, six buccolingual critical-size defects were created, and an implant was inserted into the center of each defect. One defect was filled with beta-TCP coated with rhGDF-5 (600 microg/g beta-TCP) and covered with a titanium-reinforced e-PTFE membrane (GDF group). A second defect received the same treatment, but pure uncoated beta-TCP was used (TCP group). A third defect was filled with beta-TCP mixed with autograft and not protected with a membrane (control group). The remaining three defects were filled with other biomaterials. After 2 months, total new bone area, regenerated bone height, and residual amount of beta-TCP were determined histomorphometrically. RESULTS: All implants osseointegrated. One membrane in each group became exposed. Mean new bone area for GDF, TCP, and control sites was 43.9 +/- 18.7 mm2, 32.3 +/- 16.1 mm2, and 13.1 +/- 4.0 mm2, respectively, with a significant difference between GDF and control groups. Mean regenerated bone height was 103.8 +/- 29.7%, 75.4 +/- 36.6%, and 67.2 +/- 19.1% for the GDF, TCP, and control groups, respectively. Mean residual matrix volumes were 25.9 +/- 13.6%, 30.0 +/- 13.0%, and 13.4 +/- 6.5%, respectively. Membrane protection of peri-implant defects filled with beta-TCP resulted in a stronger effect on bone regeneration, although this was not statistically significant. The most pronounced regenerative results were achieved in rhGDF-5/beta-TCP filled membrane-protected defects. CONCLUSION: Delivery of rhGDF-5 on beta-TCP might have the potential to enhance the results of GBR in peri-implant defects.

Fracture characteristics of anterior resin-bonded zirconia-fixed partial dentures.

Resin-bonded fixed partial dentures (RBFPD) are used as a minimal invasive, tooth-preventing alternative for replacing anterior teeth. Zirconia cantilever restorations were supposed to show sufficient strength for a clinical application. The aim of this investigation was to determine the fracture characteristics of cantilever and two-retainer RBFPD, which are fabricated by computer-manufactured high-strength zirconia. Human incisors and canines were used to form three groups of 14 RBFPDs with different types of preparation: group 1, an invasive cantilever; group 2, a minimal-invasive cantilever and group 3, a two-retainer RBFPD control. After thermal cycling and mechanical loading, which was performed to simulate oral service, all restorations were loaded to fracture in a universal testing machine. One half of the specimens were investigated as a control without simulated service. Mode of failure was determined for the three designs. Both cantilever groups showed comparable fracture resistance of 227 N (no. 1) and 210 N (no. 2) before thermal cycling and mechanical loading. The resistance after aging was reduced to 210 N for the invasive cantilever RBFPD and to 179 N for the minimal invasive group. Three-unit RBFPDs showed a significantly higher (p < 0.02) fracture resistance than cantilever bridges before (426 N) as well as after aging (360 N). Predominant failure was FPD and retainer fracture for the invasive cantilever design, debonding for the minimal cantilever design and RBFPD fracture for the two-retainer design. The present study revealed a significantly higher fracture resistance for two-retainer RBFPDs than for cantilever RBFPDs. The frequency of adhesive debonding increased for non-retentive prepared cantilever RBFPDs.

Influence of microgap location and configuration on the periimplant bone morphology in submerged implants. An experimental study in dogs.

OBJECTIVES: The vertical location of the implant-abutment connection influences the periimplant bone morphology. It is unknown, however, whether different microgap configurations cause different bone reactions. Therefore, in this study the bone morphologies of two different implant systems were compared. MATERIAL AND METHODS: Three months after tooth extraction in eight mongrel dogs, two grit-blasted screw implants with internal Morse taper connection (ANK group) were placed on one side whereas the contralateral side received two oxidized screw implants with external hex (TIU group). One implant on each side was placed level with the bone (equicrestal), the second implant was inserted 1.5 mm below bone level (subcrestal). After 3 months the implants were uncovered. Three months after stage two surgery, histometrical evaluations were performed in order to assess the periimplant bone levels (PBL), the first bone-to-implant contact points (BICP), the width (HBD) and the steepness (SLO) of the bone defect. RESULTS: All implants osseointegrated clinically and histologically. Bone overgrowth of the microgap was seen in ANK implants only. No significant differences between ANK and TIU could be detected in neither vertical position for PBL and BICP. However, a tendency in favor of ANK was visible when the implants were placed subcrestally. In the parameters HBD (ANK equicrestal -0.23 mm; TIU equicrestal -0.51 mm; ANK subcrestal +0.19 mm; TIU subcrestal -0.57 mm) and SLO (ANK equicrestal 35.36 degrees; TIU equicrestal 63.22 degrees; ANK subcrestal 20.40 degrees; TIU subcrestal 44.43 degrees) more pronounced and significant differences were noted. CONCLUSIONS: Within the limits of this study, it is concluded that different microgap designs cause different shapes and sizes of the periimplant ('dish-shaped') bone defect in submerged implants both in equicrestal and subcrestal positions.

A new design for post and core restorations implementing positive locking.

The design of a post and core restoration is a trade-off between a series of requirements to achieve stability of the post itself, the surrounding root dentine and the joint between tooth and post, while maintaining a sufficient apical seal of the remaining root canal filling. Post and core restoration systems come in a variety of different designs and dimensions, where each has its specific strength and weakness. With the exception of threaded versions, posts normally rely on either chemical and/or frictional locking between the post and the remaining root. Failure due to fatigue of the joint or root fracture due to overloading of the dentine is a frequent failure mode, especially for posts anchoring removable prostheses. Perforation of the root in an attempt to maximize the post length is a main cause for failure, too. A new design is proposed which uses a short but large diameter post. The risk of decementation is reduced by positive locking. A cavity with an undercut is prepared into the root, into which the post is fitted. Once joined, the post cannot be separated from the tooth without destruction of either the root or the post. The principle of the new design uses preparation tools and a post which is spread at the bottom. A cylindrically prepared hole is re-shaped to a defined inverse taper with the wider diameter at the bottom of the hole. A cylindrical post is inserted and spread at the bottom to a matching shape after placement. A first in vitro test of the stability showed that the positive locking provides at least as good extraction resistance as conventional post without the critical reliance on the luting/bonding agent.

Effect of load angulation and crown shape on forces acting on post and core restored teeth: an in vitro study.

To assess the usefulness of different post and core materials and systems, in vitro testing of fracture strength and fatigue resistance is a useful tool. However, the literature does not present coherent results as to which system can withstand the highest loads. With a geometrical model, the effects of load angulation and contact point location on the generated forces were calculated. To validate the mathematical model, a set of measurements was performed with a set-up that made it possible to measure the critical forces on a post and core restoration. A high level of correlation between the predictions of the model and the measurements was found. It was shown that the resulting forces are strongly dependent on the precise design of the test set-up and results from different geometries cannot be compared directly. Very strong sensitivity to small misalignment was found, all of which serves to explain the large differences in the literature.

Failure analysis of a new post-and-core restoration system using the finite element method.

Human teeth with substantial coronal defects are subject to reconstruction by means of post-and-core restorations. Typically, such a restoration comprises a slightly cylindrical post onto which an abutment of varying shape, depending on the designated restoration, is attached. As clinical results are not satisfactory to date, a new post-and-core design which makes use of positive locking (rather than relying on chemical bonding agents for retention in the residual root) was proposed. Using proprietary burs, an inversely conical hole is machined into the root, into which the prefabricated post-and-core restoration is inserted. This part can be spread at the bottom to match the cavity's undercut form, resulting in a positive lock which can only be separated by destruction of root, restoration or both. Another key feature of this system is a ring/groove geometry which is able to absorb the wedging forces created by said spreading and the stress of loading of the restoration which arises from mascatory forces. To assess the properties, especially in terms of the stress imposed on the remaining tooth at highest possible loading, both finite element simulations and in vitro failure tests were performed and the findings compared. The results suggest that the parameters of the finite element simulations are in good agreement with reality. As calculated and measured force levels immediately before failure of the restoration are high, the introduced new geometry has significant advantages over the classical restoration.

The influence of the root cross-section on the stress distribution in teeth restored with a positive-locking post and core design: a finite element study.

Human teeth with substantial coronal defects are subject to reconstruction by means of post and core restorations. Typically, such a restoration comprises a slightly cylindrical post onto which an abutment of varying shape, depending on the designated restoration, is attached. As clinical results are not satisfactory to date, we proposed a new proprietary post and core design which makes use of positive locking. As this prefabricated system is not customised to an individual root's cross-sectional geometry (usually oval), a varying amount of radicular dentin is left in periphery of the core's outer edge. The aim of this study was to assess the implications of this fact, i.e., whether the root has to endure higher overall stress levels which ultimately may lead to failure of one of the components involved. A series of finite element simulations were performed to evaluate stress and strain on the system, in which the proposed post and core was embedded into a virtual dentin cylinder of different diameters, ranging from flush mounting of the restoration to a dentin excess of 4 mm, and subsequently loaded with forces with two angles of attack (90 degrees and 130 degrees ). The results show that flush mounting yields an agreeable stress and strain distribution within the radicular dentin, but overall stress levels drop significantly with an excess of 0.5 mm of surrounding dentin. More than 1 mm excess was not found to have profound positive effects.

Surface conductivity of hydrogenated diamond films.

The experimentally observed high surface conductivity of hydrogenated diamond films is explained through ab initio results as well as model calculations based on the tight-binding molecular dynamics method. Our results support the previously reported experimental results indicating that the surface conductivity of the hydrogenated diamond surfaces is due to the surface adsorption of a H(3)O(+) monolayer. Specifically, it is shown that the presence of the H(3)O(+) adlayer results in the formation of an electrostatic surface dipole moment which makes the potential of the surface H layer effectively more attractive. This, in turn, ignites charge transfer from the diamond lattice to the surface layer creating, thus, the necessary charge carriers (holes) for the observed high conductivity.

Oscillatory band gap behavior in small diameter Si-clathrate nanowires.

Electronic structure analysis of small cagelike silicon nanowires is carried out and reveals many surprising features. The band gap values for all the nanowires are found to be smaller than their bulk counterparts. The most intriguing aspect appears to be the alternating sequence of direct and indirect band gaps as the diameter changes. This is attributed to the type of surface geometry. We illustrate this with two well-known clathrate forms as well as a new hexagonal clathrate structure with a direct band gap in the optical region.