MyoV: a deep learning-based tool for the automated quantification of muscle fibers.

Accurate approaches for quantifying muscle fibers are essential in biomedical research and meat production. In this study, we address the limitations of existing approaches for hematoxylin and eosin-stained muscle fibers by manually and semiautomatically labeling over 660 000 muscle fibers to create a large dataset. Subsequently, an automated image segmentation and quantification tool named MyoV is designed using mask regions with convolutional neural networks and a residual network and feature pyramid network as the backbone network. This design enables the tool to allow muscle fiber processing with different sizes and ages. MyoV, which achieves impressive detection rates of 0.93-0.96 and precision levels of 0.91-0.97, exhibits a superior performance in quantification, surpassing both manual methods and commonly employed algorithms and software, particularly for whole slide images (WSIs). Moreover, MyoV is proven as a powerful and suitable tool for various species with different muscle development, including mice, which are a crucial model for muscle disease diagnosis, and agricultural animals, which are a significant meat source for humans. Finally, we integrate this tool into visualization software with functions, such as segmentation, area determination and automatic labeling, allowing seamless processing for over 400 000 muscle fibers within a WSI, eliminating the model adjustment and providing researchers with an easy-to-use visual interface to browse functional options and realize muscle fiber quantification from WSIs.

The anthraquinone derivative KA-4s reduces energy metabolism and enhances the sensitivity of ovarian cancer cells to cisplatin.

Ovarian cancer is the leading cause of death from female gynecological cancers. Cisplatin (DDP) is a first-line drug for ovarian cancer treatment. Due to DDP resistance, there is an urgent need for novel therapeutic drugs with improved antitumor activity. AMPK-mediated metabolic regulatory pathways are related to tumor drug resistance. Our study aimed to determine the relationship between reversing DDP resistance with the anthraquinone derivative KA-4s and regulating AMPK energy metabolism in ovarian cancer. The results showed that KA-4s inhibited the proliferation of ovarian cancer cells. The combination of KA-4s with DDP effectively promoted drug-resistant ovarian cancer cell apoptosis and inhibited cell migration and invasion. Moreover, KA-4s decreased the intracellular ATP level and increased the calcium ion level, leading to AMPK phosphorylation. Further studies suggested that the AMPK signaling pathway may be involved in the mechanism through which KA-4s reduce drug resistance. KA-4s inhibited mitochondrial respiration and glycolysis; downregulated the glucose metabolism-related proteins GLUT1 and GLUT4; the lipid metabolism-related proteins SREBP1 and SCD1; and the drug resistance-related proteins P-gp, MRP1, and LRP. The inhibitory effect of KA-4s on GLUT1 was confirmed by the application of the GLUT1 inhibitor BAY-876. KA-4s combined with DDP significantly increased the expression of p-AMPK and reduced the expression of P-gp. In a xenograft model of ovarian cancer, treatment with KA-4s combined with DDP reduced energy metabolism and drug resistance, inducing tumor apoptosis. Consequently, KA-4s might be evaluated as a new agent for enhancing the chemotherapeutic efficacy of treatment for ovarian cancer.

Accuracy of open-sleeved vs. closed-sleeved static computer-assisted implant systems in immediate maxillary molar implant placement: An in vitro study.

OBJECTIVES: The objective of this study is (1) to compare the accuracy of an open-sleeved static computer-assisted implant system (sCAIS) with a closed-sleeve sCAIS and free-hand approach in immediate implant placement (IIP) of maxillary molar sites and (2) to investigate the influence of socket morphology on these approaches. MATERIALS AND METHODS: Ninety partially edentulous duplicated maxillary models simulating three different molar sockets (type A, B, and C based on Smith and Tarnow's classification) were investigated. Three modalities, including sCAIS with open-sleeves, sCAIS with closed-sleeves, and free-hand approach, were applied separately to 30 models with 120 sockets. A customized Python script automatically measured the deviations between the virtual and actual implant positions for all 360 implants. RESULTS: The 3D deviations of sCAIS were significantly influenced by the socket and sleeve types. Both guided groups exhibited significantly less deviation than the free-hand approach. Type A and C sockets resulted in better implant positions than type B socket sites. In type B sockets, the open-sleeve group achieved significantly less deviation compared to the closed-sleeve group, with respect to apical global (1.34 ± 0.53 vs. 1.84 ± 0.59 mm), coronal horizontal (0.68 ± 0.36 vs. 0.93 ± 0.34 mm), apical horizontal (1.21 ± 0.59 vs. 1.74 ± 0.63 mm), and angular (3.30 ± 1.41 vs. 4.41 ± 1.96°) deviations. CONCLUSIONS: Guided implant surgery significantly reduces deviations during molar IIP compared to free-hand procedures. Furthermore, the use of open-sleeve sCAIS appears to be more effective in minimizing deviations in type B sockets when compared with the closed-sleeve guided system.

Accuracy of edentulous full-arch implant impression: An in vitro comparison between conventional impression, intraoral scan with and without splinting, and photogrammetry.

OBJECTIVES: The purpose of this in vitro study was to compare the trueness and precision of complete arch implant impressions using conventional impression, intraoral scanning with and without splinting, and stereophotogrammetry. MATERIALS AND METHODS: An edentulous model with six implants was used in this study. Four implant impression techniques were compared: the conventional impression (CI), intraoral scanning (IOS) without splinting, intraoral scanning with splinting (MIOS), and stereophotogrammetry (SPG). An industrial blue light scanner was used to generate the baseline scan from the model. The CI was captured with a laboratory scanner. The reference best-fit method was then applied in the computer-aided design (CAD) software to compute the three-dimensional, angular, and linear discrepancies among the four impression techniques. The root mean square (RMS) 3D discrepancies in trueness and precision between the four impression groups were analyzed with a Kruskal-Wallis test. Trueness and precision between single analogs were assessed using generalized estimating equations. RESULTS: Significant differences in the overall trueness (p = .017) and precision (p < .001) were observed across four impression groups. The SPG group exhibited significantly smaller RMS 3D deviations than the CI, IOS, and MIOS groups (p < .05), with no significant difference detected among the latter three groups (p > .05). CONCLUSIONS: Stereophotogrammetry showed superior trueness and precision, meeting misfit thresholds for implant-supported complete arch prostheses. Intraoral scanning, while accurate like conventional impressions, exhibited cross-arch angular and linear deviations. Adding a splint to the scan body did not improve intraoral scanning accuracy.

Tubular TMEM16A promotes tubulointerstitial fibrosis by suppressing PGC-1α-mediated mitochondrial homeostasis in diabetic kidney disease.

Tubulointerstitial fibrosis (TIF) plays a crucial role in the progression of diabetic kidney disease (DKD). However, the underlying molecular mechanisms remain obscure. The present study aimed to examine whether transmembrane member 16A (TMEM16A), a Ca2+-activated chloride channel, contributes to the development of TIF in DKD. Interestingly, we found that TMEM16A expression was significantly up-regulated in tubule of murine model of DKD, which was associated with development of TIF. In vivo inhibition of TMEM16A channel activity with specific inhibitors Ani9 effectively protects against TIF. Then, we found that TMEM16A activation induces tubular mitochondrial dysfunction in in vivo and in vitro models, with the evidence of the TMEM16A inhibition with specific inhibitor. Mechanically, TMEM16A mediated tubular mitochondrial dysfunction through inhibiting PGC-1α, whereas overexpression of PGC-1α could rescue the changes. In addition, TMEM16A-induced fibrogenesis was dependent on increased intracellular Cl-, and reducing intracellular Cl- significantly blunted high glucose-induced PGC-1α and profibrotic factors expression. Taken together, our studies demonstrated that tubular TMEM16A promotes TIF by suppressing PGC-1α-mediated mitochondrial homeostasis in DKD. Blockade of TMEM16A may serve as a novel therapeutic approach to ameliorate TIF.

Effect of melatonin on cryopreservation of Beijing you chicken (gallus gallus) spermatozoa.

Beijing You Chicken, a valuable local chicken breed from Beijing, China, was once listed as an endangered breed. From the point of view of conservation, the preservation of this breed is an important task for the local researchers. Semen cryopreservation is a popular method to maintain valuable species. However, during cryopreservation, semen is susceptible to oxidative damage. Melatonin is a potent antioxidant and free radical scavenger, so it has been selected to improve the efficiency of sperm cryopreservation. In this study, the chicken semen was treated with different concentrations of melatonin in the cryopreservation solution. The results showed that melatonin at concentrations of 10-3 M and 10-5 M significantly improved sperm progressive motility and total motility, respectively, compared to the control (P < 0.05). Melatonin at 10-3 M also significantly improved the plasma membrane and acrosome integrity of spermatozoa compared to the control. The mechanisms are that melatonin significantly reduces the level of ROS and preserves sperm mitochondrial membrane potential. Most importantly, the melatonin-treated cryopreserved chicken sperm after artificial insemination significantly increased the hatching rate of chicks compared to the control (p < 0.05). The results show that melatonin has a positive effect on the quality of the cryopreserved spermatozoa. These results provide the theoretical and practical basis for using melatonin to improve Beijing You Chicken conservation, and they may also be applicable to poultry as a whole.

New online dynamic nomograms to predict recurrence-free and overall survival after resection of endometrial cancer: a single-institution retrospective cohort study.

PURPOSE: The significant global burden of endometrial cancer (EC) and the challenges associated with predicting EC recurrence indicate the need for a dynamic prediction model. This study aimed to propose nomograms based on clinicopathological variables to predict recurrence-free survival (RFS) and overall survival (OS) after surgical resection for EC. METHODS: This single-institution retrospective cohort study included patients who underwent surgical resection for EC. Web-based nomograms were developed to predict RFS and OS following resection for EC, and their discriminative and calibration abilities were assessed. RESULTS: This study included 289 patients (median age, 56 years). At a median follow-up of 51.1 (range, 4.1-128.3) months, 13.5% (39/289) of patients showed relapse or died, and 10.7% (31/289) had non-endometrioid tumors (median size: 2.8 cm). Positive peritoneal cytology result (hazard ratio [HR], 35.06; 95% confidence interval [CI], 1.12-1095.64; P = 0.0428), age-adjusted Charlson comorbidity index (AACCI) (HR, 52.08; 95% CI, 12.35-219.61; P < 0.001), and FIGO (Federation of Gynecology and Obstetrics) stage IV (HR, 138.33; 95% CI, 17.38-1101.05; P < 0.001) were predictors of RFS. Similarly, depth of myometrial invasion ≥ 1/2 (HR, 1; 95% CI, 0.46-2.19; P = 0.995), AACCI (HR, 93.63; 95% CI, 14.87-589.44; P < 0.001), and FIGO stage IV (HR, 608.26; 95% CI, 73.41-5039.66; P < 0.001) were predictors of OS. The nomograms showed good predictive capability, positive discriminative ability, and calibration (RFS: 0.895 and OS: 0.891). CONCLUSION: The nomograms performed well in internal validation when patients were stratified into prognostic groups, offering a personalized approach for risk stratification and treatment decision-making.

Temperature-induced embryonic diapause in chickens is mediated by PKC-NF-κB-IRF1 signaling.

BACKGROUND: Embryonic diapause (dormancy) is a state of temporary arrest of embryonic development that is triggered by unfavorable conditions and serves as an evolutionary strategy to ensure reproductive survival. Unlike maternally-controlled embryonic diapause in mammals, chicken embryonic diapause is critically dependent on the environmental temperature. However, the molecular control of diapause in avian species remains largely uncharacterized. In this study, we evaluated the dynamic transcriptomic and phosphoproteomic profiles of chicken embryos in pre-diapause, diapause, and reactivated states. RESULTS: Our data demonstrated a characteristic gene expression pattern in effects on cell survival-associated and stress response signaling pathways. Unlike mammalian diapause, mTOR signaling is not responsible for chicken diapause. However, cold stress responsive genes, such as IRF1, were identified as key regulators of diapause. Further in vitro investigation showed that cold stress-induced transcription of IRF1 was dependent on the PKC-NF-κB signaling pathway, providing a mechanism for proliferation arrest during diapause. Consistently, in vivo overexpression of IRF1 in diapause embryos blocked reactivation after restoration of developmental temperatures. CONCLUSIONS: We concluded that embryonic diapause in chicken is characterized by proliferation arrest, which is the same with other spices. However, chicken embryonic diapause is strictly correlated with the cold stress signal and mediated by PKC-NF-κB-IRF1 signaling, which distinguish chicken diapause from the mTOR based diapause in mammals.

Barriers and facilitators in implementing early essential newborn care of well-born babies in low- and middle-income countries: A mixed-method systematic review.

BACKGROUND: Evidences have demonstrated the effectiveness of early essential newborn care. However, the implementation of early essential newborn care is suboptimal. The aim is to identify and synthesise the barriers and facilitators impacting the implementation of early essential newborn care in low- and middle-income countries. DATA SOURCES: PubMed, EMBASE, Cochrane Central Register of Controlled Trials, PsycINFO, CINAHL, CNKI, Wan Fang Data, SinoMed and Google Scholar. METHODS: Two authors independently screened, performed quality assessment using the Mixed Methods Appraisal Tool and extracted data. This review includes papers that reported the barriers and facilitators of implementing early essential newborn care in low- and middle-income countries from the view of healthcare providers. Barriers and facilitators were coded according to the consolidated framework for implementation research in a deductive way and then been inducted into five common themes. This review followed synthesis without meta-analysis reporting guideline. RESULTS: A total of 28 studies were included. Five inductive common themes influencing implementing early essential newborn care in low- and middle-income countries were system-level healthcare factors, healthcare providers' knowledge and beliefs, the requirements of mothers or families, adapting to routine practice and the working climate of organisation. CONCLUSION: The factors were from system level, facility level and individual level and were inducted into five themes. Based on this review, decision-makers could tailor implementing strategies to narrow the gap between the evidence and implementation. RELEVANCE TO CLINICAL PRACTICE: The study offers guidance for health professionals to identify barriers and facilitators in implementing early essential newborn care and make tailored strategies when implementing early essential newborn care. PATIENT OR PUBLIC CONTRIBUTION: No patient or public contributions.

Psychological distress in adult women of reproductive age at different stages after breast cancer diagnosis: A qualitative study.

AIM: To explore the actual experience of psychological distress of adult women of reproductive age at different stages after breast cancer diagnosis. DESIGN: Qualitative. METHODS: Eighty-one patients with breast cancer-related distress thermometer scores >4 were selected using a purposive sampling method. Patients were divided into newly diagnosed and 1-, 3-, 6-, 9- and 12-month groups according to time since diagnosis and then interviewed. A phenomenological approach was adopted to analyse interview content, and different themes were extracted. RESULTS: Women exhibited different levels of psychological distress depending on the time since diagnosis, with newly diagnosed patients showing the highest distress. Within 1 year post-diagnosis, different events caused patients distress. Themes extracted at new diagnosis and 1-, 3-, 6-, 9- and 12 months post-diagnosis included sadness and disbelief, loss of control, optimistic but concerned, physical and mental exhaustion, difficulties returning to society and limited sexual intimacy, respectively; all groups expressed reproductive concerns. CONCLUSION: Clinical nurses should focus on different psychologically distressing events to provide targeted interventions at distinct phases. For women of childbearing age, clinical nurses should pay particular attention to patients' marriage and reproductive concerns. IMPLICATIONS FOR THE PROFESSION AND/OR PATIENT CARE: During the year after a breast cancer diagnosis, patients of childbearing age experience events that cause psychological distress that differ depending on time since diagnosis. Nurses should focus on core stressful events and perform specific nursing interventions. IMPACT: To provide holistic care, nurses should consider the psychological and emotional changes patients may undergo. For women of childbearing age, clinical nurses should pay particular attention to patients' marriage and fertility concerns, and be able to provide evidence-based professional guidance on reproductive preservation techniques. REPORTING METHOD: The study was reported using the consolidated criteria for reporting qualitative research guidelines. PATIENT OR PUBLIC CONTRIBUTION: Patients contributed to data collection through interviews.

Reversible Thermally Driven Phase Change of Layered In2Se3 for Integrated Photonics.

Two-dimensional In2Se3, an unconventional phase-change material, has drawn considerable attention for polymorphic phase transitions and electronic device applications. However, its reversible thermally driven phase transitions and potential use in photonic devices have yet to be explored. In this study, we observe the thermally driven reversible phase transitions between α and ß' phases with the assistance of local strain from surface wrinkles and ripples, as well as reversible phase changes within the ß phase family. These transitions lead to changes in the refractive index and other optoelectronic properties with minimal optical loss at telecommunication bands, which are crucial in integrated photonic applications such as postfabrication phase trimming. Additionally, multilayer ß'-In2Se3 working as a transparent microheater proves to be a viable option for efficient thermo-optic modulation. This prototype design for layered In2Se3 offers immense potential for integrated photonics and paves the way for multilevel, nonvolatile optical memory applications.

Integrated Flexible Microscale Mechanical Sensors Based on Cascaded Free Spectral Range-Free Cavities.

Photonic mechanical sensors offer several advantages over their electronic counterparts, including immunity to electromagnetic interference, increased sensitivity, and measurement accuracy. Exploring flexible mechanical sensors on deformable substrates provides new opportunities for strain-optical coupling operations. Nevertheless, existing flexible photonics strategies often require cumbersome signal collection and analysis with bulky setups, limiting their portability and affordability. To address these challenges, we propose a waveguide-integrated flexible mechanical sensor based on cascaded photonic crystal microcavities with inherent deformation and biaxial tensile state analysis. Leveraging the advanced multiplexing capability of the sensor, for the first time, we successfully demonstrate 2D shape reconstruction and quasi-distributed strain sensing with 110 µm spatial resolution. Our microscale mechanical sensor also exhibits exceptional sensitivity with a detected force level as low as 13.6 µN in real-time measurements. This sensing platform has potential applications in various fields, including biomedical sensing, surgical catheters, aircraft and spacecraft engineering, and robotic photonic skin development.

What can be done to protect toddlers from air pollution: Current evidence.

PROBLEM: Toddlers are more prone to exposure to widely distributed air pollution and to health damage from it. However, systematic summaries of evidence on protective behaviors against air pollution for toddlers are lacking. OBJECTIVE: To identify currently available evidence on protective behaviors against air pollution for toddlers. METHODS: The literature retrieval was performed in selected databases, limited from 2002 to 2022. Studies meeting the following criteria were included and praised: 1) clinical practice guideline, systematic review, expert consensus, recommended practice, randomized control test (RCT) or cohort study published in Chinese or English; 2) studies reporting effects of protective behaviors against air pollution on toddlers' health outcomes or providing recommendation on these behaviors. The evidence in the included studies was extracted, synthesized and graded for evidence summary. RESULTS: Studies (N = 19) were used for evidence summary development and 35 pieces of best evidence were synthesized, which were divided into three categories, including "avoiding or reducing air pollution generation", "removing existing air pollution", and "avoiding or reducing exposure to existing air pollution". CONCLUSIONS: More evidence is needed to identify protective measures against outdoor air pollution and tobacco smoke. Research in the future should focus on the safety, effectiveness and feasibility of universal measures implemented in toddlers, and try to develop protective measures specific to toddlers which highlight their special nature. IMPLICATIONS: The results of this study can help pediatric nurses provide individualized advice and assistance for toddlers and their families, and conduct research on the effectiveness of toddler-targeting protective behaviors more efficiently.

Identification of Candidate Genes for Red-Eyed (Albinism) Domestic Guppies Using Genomic and Transcriptomic Analyses.

Guppies are small tropical fish with brightly colored bodies and variable tail shapes. There are two phenotypes of domestic guppy eye color: red and black. The wild type is black-eyed. The main object of this study was to identify candidate genes for the red-eyed phenotype in domestic guppies. We hope to provide molecular genetic information for the development of new domestic guppy strains. Additionally, the results also contribute to basic research concerning guppies. In this study, 121 domestic guppies were used for genomic analysis (GWAS), and 44 genes were identified. Furthermore, 21 domestic guppies were used for transcriptomic analysis, and 874 differentially expressed genes (DEGs) were identified, including 357 upregulated and 517 downregulated genes. Through GO and KEGG enrichment, we identified some important terms or pathways mainly related to melanin biosynthesis and ion transport. qRT-PCR was also performed to verify the differential expression levels of four important candidate genes (TYR, OCA2, SLC45A2, and SLC24A5) between red-eyed and black-eyed guppies. Based on the results of genomic and transcriptomic analyses, we propose that OCA2 is the most important candidate gene for the red-eyed phenotype in guppies.

Recommendations for successful virtual patient-assisted esthetic implant rehabilitation: A guide for optimal function and clinical efficiency.

OBJECTIVE: Complete arch implant rehabilitation necessitates meticulous treatment planning and high-level collaboration between surgical and prosthetic dental teams. Emerging virtual technologies hold considerable promise in streamlining this process. The aim of this article is to extend recommendations to clinicians venturing into the virtual patient-assisted esthetic implant rehabilitation workflow. OVERVIEW: This article summarizes recommendations for virtual patient-assisted esthetic implant rehabilitation in the following five aspects: three-dimensional data handling and superimposition, occlusion and virtual articulator integration in creating virtual patients, streamlined face- and prosthetic-driven surgical planning, reuse of presurgical data ("Copy & Paste"), and final impression for passive fitting of final restoration. To illustrate these principles, a case with complete-mouth implant rehabilitation completed within six visits using this virtual patient workflow is presented. CONCLUSION: The virtual patient workflow serves as an invaluable tool to perform treatment planning, enhance efficiency, and ensure predictable outcomes in esthetic complete arch implant rehabilitation. CLINICAL SIGNIFICANCE: Virtual workflows are increasingly prevalent in esthetic implant rehabilitation. Nevertheless, these workflows necessitate a distinct set of knowledge and tools divergent from conventional dentistry practices. This article offers guidelines and recommendations for dental clinicians who are new to this field.

Regulation of Follicular Development in Chickens: WIF1 Modulates Granulosa Cell Proliferation and Progesterone Synthesis via Wnt/ß-Catenin Signaling Pathway.

Proliferation, apoptosis, and steroid hormone secretion by granulosa cells (GCs) and theca cells (TCs) are essential for maintaining the fate of chicken follicles. Our previous study showed that the Wnt inhibitor factor 1 (WIF1) plays a role in follicle selection. However, the significance of WIF1 in GC- and TC-associated follicular development was not explicitly investigated. This study found that WIF1 expression was strongly downregulated during follicle selection (p < 0.05) and was significantly higher in GCs than in TCs (p < 0.05). WIF1 inhibits proliferation and promotes apoptosis in GCs. Additionally, it promotes progesterone secretion in prehierarchal GCs (pre-GCs, 1.16 ± 0.05 ng/mg vs. 1.58 ng/mg ± 0.12, p < 0.05) and hierarchal GCs (hie-GCs, 395.00 ng/mg ± 34.73 vs. 527.77 ng/mg ± 27.19, p < 0.05) with the participation of the follicle-stimulating hormone (FSH). WIF1 affected canonical Wnt pathways and phosphorylated ß-catenin expression in GCs. Furthermore, 604 upregulated differentially expressed genes (DEGs) and 360 downregulated DEGs in WIF1-overexpressed GCs were found through RNA-seq analysis (criteria: |log2⁡(FoldChange)| > 1 and p_adj < 0.05). Cytokine-cytokine receptor interaction and the steroid hormone biosynthesis pathway were identified. In addition, the transcript of estrogen receptor 2 (ESR2) increased significantly (log2⁡(FoldChange) = 1.27, p_adj < 0.05). Furthermore, we found that WIF1 regulated progesterone synthesis by upregulating ESR2 expression in GCs. Additionally, WIF1 suppressed proliferation and promoted apoptosis in TCs. Taken together, these results reveal that WIF1 stimulates follicle development by promoting GC differentiation and progesterone synthesis, which provides an insight into the molecular mechanism of follicle selection and egg-laying performance in poultry.

Superimposing digital arch scans onto cone beam computed tomography scans with metallic artifacts by applying a radiopaque occlusal registration material: A chairside dental technique.

Precise alignment between digital arch scans and cone beam computed tomography (CBCT) scans is a crucial step in computer-aided implant planning and placement. However, clinicians frequently encounter challenges during this process when imaging patients with existing metal restorations or orthodontic devices, as these can introduce metallic artifacts on CBCT scans that lead to alignment deviations. The presented technique describes a straightforward approach using a radiopaque occlusal registration material as a radiographic marker to facilitate the alignment between digital arch scans and CBCT scans with metallic artifacts. This technique simplifies the clinical workflow by eliminating the need for additional radiographic templates or specialized devices, offering a cost-effective option for clinicians.

The 4D virtual patient: A proof of concept in digital dentistry.

This dental technique article updates the 3-dimensional (3D) virtual patient digital workflow by introducing the space-time information acquired with jaw tracking motion. The direct digital procedure involved scanning the interim prostheses, creating virtual casts, and transferring the digital facebow, virtual articulation, and jaw-tracking motion. All 3D files and records from the intraoral scanner, cone beam computed tomography, extraoral scanner, and jaw tracking motion were superimposed using existing teeth as the connecting link in all data sets and adopting the best-fit alignment. The main advantages of the technique were creating a 4-dimensional virtual patient and standardizing the introduction of clinical space-time information (the fourth dimension) beyond the static condition.

Digital cross-mounting of intraoral scan casts from a virtual articulator to a mechanical articulator by using a custom transfer plate: A dental technique.

With the development of digital dental technologies, a complete digital workflow without using physical casts has become possible. However, for certain clinical and dental laboratory procedures, especially in complex rehabilitation treatments, physically mounted casts in an ideal location in a mechanical articulator are still necessary for treatment planning and restoration fabrication. This technique report describes a digital approach to fabricating a custom transfer plate to cross mount intraoral scan casts from a virtual articulator to the corresponding mechanical articulator. This technique eliminates the need for conventional physical facebow transfer processes and offers a straightforward approach to integrating virtual procedures with analog workflows.

Influence of apical finish line location of tooth preparations on the scanning accuracy of intraoral scanners with various focal lengths and scanning technologies.

STATEMENT OF PROBLEM: Limited studies have reported the influence of finish line location on the accuracy of intraoral scanners (IOSs). Focal length is a hardware characteristic of IOSs. Whether there is a relationship between scanning accuracy of tooth preparations with the finish located at different apical positions and focal length and IOS technology or system remains uncertain. PURPOSE: The purpose of the present in vitro study was to assess the influence of the apical finish line location of tooth preparations on the accuracy of 4 IOSs with various focal lengths and scanning technologies. MATERIAL AND METHODS: A maxillary typodont with a crown preparation on the left first molar was digitized (T710). Afterwards, a removable die was created on the prepared first molar of the virtual cast and duplicated to create 4 dies with different apical finish line locations: 2- or 1-mm supragingival, 0-mm or equigingival, and -0.5-mm or intracrevicular. The cast and die designs were additively fabricated (Asiga Pro 4K with Keystone Model Ultra). Each die was independently scanned by using the same laboratory scanner (reference scans). Four groups were created: TRIOS 5, i700, iTero, and Primescan. Four subgroups were developed depending on the apical position of the finish line (n=15). In each subgroup, the cast was assembled by positioning the corresponding die into the cast. The cast was then scanned by using the corresponding IOS. The reference scans were used as a control to compute the root mean square (RMS) error discrepancies with each experimental scan on the preparation and margin of the preparation areas. Two-way ANOVA and pairwise comparisons were used to analyze trueness (α=.05). The Levene and pairwise comparisons using the Wilcoxon Rank sum test were used to analyze precision (α=.05). RESULTS: Trueness discrepancies in the preparation area were found among the groups (P=.010) and subgroups (P<.001), with a significant interaction between group×subgroup (P<.001). The -0.5 mm location obtained significantly worse trueness in the preparation area. The TRIOS 5 and i700 obtained the best trueness in the preparation area. Trueness discrepancies in the margin area were found among the groups (P=.002) and subgroups (P<.001), with a significant interaction between group×subgroup (P=.004). The -0.5 mm location obtained the worst trueness in the margin area. The i700 and Primescan obtained the best trueness in the margin area. Precision discrepancies were found in the preparation area (P<.001). The TRIOS 5 obtained the best precision in the preparation area (P=.001). Precision discrepancies in the margin area were obtained (P<.001). The 1-mm subgroup obtained the best precision (P=.001). CONCLUSIONS: The apical position of the finish line of the tooth preparation tested affected the trueness and precision of the IOSs tested.