Statement Of Problem: Studies analyzing the accuracy of intraoral scanners (IOSs) for fabricating veneer restorations are scarce. Also, the space between tooth preparations significantly impacts the accuracy of IOSs. The influence of interdental space on the accuracy of veneer preparations digitized by using IOSs remains uncertain.
Purpose: The purpose of the present in vitro study was to assess the influence of interdental spaces and operator experience on the accuracy, scanning time, and number of photograms of an IOS for acquiring the virtual definitive casts for fabricating 2 adjacent veneer restorations.
Material And Methods: A maxillary model with the 6 anterior teeth with a veneer preparation on both central incisors was virtually design. Three casts were printed each with a different interdental space between the preparations: 0.5, 1.0, and 1.5 mm. Each cast was scanned with an IOS (TRIOS 3) by an experienced and an inexperienced operator (n=10). The scanning time and number of photograms were registered. Linear measurements were obtained between the mesial surfaces of both veneer preparations in the virtual reference casts and experimental scans aiming to assess the interspace reproduction capabilities of each subgroup tested. Specimens with a bridge scanning error were registered. Two-way ANOVA and pairwise multiple comparisons were used to analyze trueness, scanning time, and number of photograms (α=.05). Levene and pairwise comparisons using Wilcoxon Rank sum tests were used to analyze precision (α=.05).
Results: All the specimens of the InExp-0.5 subgroup and 30% of scans in the InExp-0.5 subgroup had a bridge scanning error. Significant trueness, precision, scanning time, and number of photograms discrepancies were found among the groups (P<.001) and subgroups (P<.001), with a significant interaction between group×subgroup (P<.001). In the 0.5 group, there were trueness (P<.001) and precision discrepancies between the experienced and inexperienced operator. The experienced operator demonstrated better trueness and precision scanning the 0.5-mm cast when compared with the other reference casts (P<.001). The inexperienced operator revealed lower trueness when scanning the 0.5-mm cast when compared with the 1.0- (P<.001) and 1.5-mm (P<.001) casts. Scanning time discrepancies were revealed between the operators in the 1.0 (P<.001) and 1.5 groups (P<.001). For the inexperienced operator, the 1.0 and 1.5 groups (P<.001) were significantly different. Number of photogram discrepancies were revealed between the operators in the 1.0 group (P<.001) and 1.5 group (P<.001). Additionally, for the inexperienced operator, the 1.0 and 1.5 groups were significantly different (P<.001).
Conclusions: The interdental spaces and operator experience impacted the scanning accuracy, scanning time, and number of photograms of the IOS tested. The inexperienced operator was unable to scan the 0.5-mm interdental space and demonstrated similar scanning trueness and precision when scanning the 1.0- and 1.5-mm reference casts, but higher scanning time and number of photograms when compared with the experienced operator.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.prosdent.2025.02.011 | DOI Listing |
J Glaucoma
March 2025
Department of Ophthalmology, Harvey and Bernice Jones Eye Institute, University of Arkansas for Medical Sciences, Little Rock, AR.
Precis: In this prospective multicenter study, eyes with primary congenital glaucoma exhibited lower retinal vascular parameters compared to healthy controls, as assessed by optical coherence tomography angiography fractal dimension analysis.
Purpose: To study the retino-choroidal peripapillary microvascular pattern in primary congenital glaucoma (PCG) using fractal dimension (FD) analysis and compare it to healthy controls.
Methods: This was a prospective multicenter comparative study.
The instant crystallization of semi-crystalline polymers has become possible following the recent advances in Fast Scanning Calorimetry (FSC) and enables us to make a bridge between the time scale available experimentally with those accessible with computer simulations. Although the FSC observations have provided new information on the crystallization kinetics and evolution of the crystals, the molecular details on the chain exchange events between the ordered and disordered domains of crystals have remained elusive. Using molecular dynamics simulations, we examined the detailed chain dynamics and thermodynamics of polyamide 6 (PA6) system under two heating treatments: (i) quenching PA6 melt deeply below the melting temperature Tm and (ii) annealing the resulting quenched system to a temperature close to Tm.
View Article and Find Full Text PDFRheumatology (Oxford)
March 2025
Section of Cardiorespiratory Medicine, Victor Phillip Dahdaleh Heart and Lung Research Institute, University of Cambridge, Cambridge, UK.
Imaging plays an important role in the clinical management of patients with large-vessel vasculitis (LVV), both to confirm the diagnosis at the time of initial presentation and to identify disease relapses in individuals with established disease. The big advantage of PET imaging over other non-invasive imaging modalities is the ability to employ targeted radionuclide probes to localize and track cellular pathways, providing in vivo assessments of disease activity. While 18F-fluorodeoxyglucose (FDG) has good diagnostic accuracy for LVV, this tracer is taken up by all glucose metabolizing cells in the vessel wall and so non-specific arterial uptake that is often unrelated to inflammatory disease activity can occur in patients despite a good clinical response to treatment.
View Article and Find Full Text PDFWearable Technol
March 2025
Department of Mechanical Engineering, Northwestern University, Evanston, IL, USA.
Eye gaze tracking is increasingly popular due to improved technology and availability. In the domain of assistive device control, however, eye gaze tracking is often used in discrete ways (e.g.
View Article and Find Full Text PDFSovrem Tekhnologii Med
March 2025
MD, PhD, Senior Researcher, Laboratory of Cell Technologies; Federal Scientific and Clinical Center of the Federal Medical Biological Agency of Russia, 28 Orekhovy Blvd., Moscow, 115682, Russia; Head of the Laboratory of Solid Tumor Immunotherapy; Federal Center of Brain Research and Neurotechnologies of the Federal Medical Biological Agency of Russia, 1, Bldg. 10, Ostrovityanova St., Moscow, 117513, Russia; Senior Researcher, Laboratory of Molecular Regeneration Mechanisms; Engelhardt Institute of Molecular Biology of the Russian Academy of Sciences, 32 Vavilov St., Moscow, 119991, Russia.
Unlabelled: One of the alternative approaches to glioblastoma treatment is cellular immunotherapy based on natural killer cells (NK cells). To enhance their cytotoxic effect on tumor cells, new NK cell lines are being created using genetic engineering techniques. was to evaluate the impact efficacy of "enhanced" NK cells on early metabolic rearrangements and the viability of glioblastoma cells in a patient using a tumor spheroid model.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!