Background: Numerous studies showed that the CONVERGENCE angle (CA) of prepared teeth for fixed prosthodontics in the clinical practice is greater than the recommended values.Objectives: This cross-sectional study aimed to compare the total occlusal CONVERGENCE (TOC) ANGLES of metal ceramic fixed prosthodontics among dental students [final-year undergraduate (UG) and Master Prosthodontics (MS) students] and general practitioners (GP) in their private clinics with the recommended value (£12 degrees).Methods: The buccolingual (BL) and mesiodistal (MD) TOC of 114, 90, and 111 stone dies referred to UG, MS, and GP, respectively, were measured. These dies included incisors, premolars, and molars. One sample Wilcoxon signed rank test, Mann-Whitney U test, Kruskal-Wallis, and Fisher exact test were used for statistical analysis.Results: Mean values of TOC for UG were 27.8 degrees BL and 20.9 degrees MD, whereas they were 30.6 degrees BL and 18.2 degrees MD for MS. GP had TOC of 35.5 degrees BL and 24 degrees MD. GP had significantly higher TOC values than the other groups (0.001>P value £0.007). In each group, TOC did not differ when calculated for partial fixed prosthodontic and single crown abutments (0.117£ P value £0.797). Molars in general had the highest TOC values. Only 0.9%, 3.3%, and 0.9% of UG, MS, and GP, respectively, respected the TOC £12 degrees.Conclusions: In all the groups, tooth preparations were inconsistent with the recommended TOC values, even among specialists in fixed prosthodontics. These results support the existing literature that the recommended values were rarely achieved and may require reconsideration.Clinical Significance: Clinically, the CA values of prepared teeth for fixed prosthodontics exceed the recommended values in most cases, not only among general practitioners, but also among students in academic institutes. Thus, the effects of teeth preparations with CA greater than the recommended values on the longevity of the prosthodontics should be further investigated.

BACKGROUND AND OBJECTIVE: One of the important factors in the longevity of fixed restorations is fundamental considerations of tooth preparation. One of these fundamentals is axial walls preparation with minimum tapering for retention and resistance form. The aim of this study was to assess CONVERGENCE ANGLES of tooth preparation for Porcelain Fused to Metal (PFM) restorations by general dentists. METHODS: Referring to Mashhad dental laboratories, 600 die patterns were collected, and divided into five groups including maxillary and mandibular anterior teeth, premolars, maxillary and mandibular molars (120 in each group). Photographic views of the samples were taken by a digital camera (EOS-450D model) to exactly examine the CONVERGENCE of the tooth walls. One photograph was taken from the facial surface, and the other taken from the proximal. ANGLES related to the tapering of axial walls, in mesiodistal and faciolingual dimensions were measured by using engineering software (AutoCAD 2008) for each die. Also, the inclination of buccal and lingual walls of posterior teeth was measured separately and then assessed and compared with the standards.FINDINGS: Mean M-D and F-L CONVERGENCE angle for maxillary and mandibular molars, premolar, maxillary and mandibular teeth were (31.02±10.72, 28.48±11.92), (32.06±9.98, 37.14±11.92), (21.83±7.46, 24.25±11.72), (28.66±13.18, 15.51±8.98) and (31.31±13.78, 18.11±7.95) degrees, respectively. M-D and F-L tapering in all groups have statistical significant difference with optimum degree of tooth preparation taper. Also there was a significant difference between M-D and F-L tapering in all groups (p<0.001). Inclination of preparation in posterior teeth's also measured buccal inclination is bigger than of lingual walls in posterior teeth (p<0.001). CONCLUSION: According to results of this study, in all cases the tapering ANGLES were more than normal. M-D and F-L tapering in mandibular molars were more than the others. Tendency of dentists was to more tapering in buccal than lingual surfaces in posterior teeth.

Purpose: The present study aims to identify and explain the futures of Iranian provinces in the competition for the development of NBIC technological CONVERGENCE (synergy between nanotechnology, biotechnology, information technology and cognitive sciences) with a focus on Yazd province. Method: This research, which has been conducted with a qualitative and descriptive approach, is classified as an exploratory futures-study. In this way, the relevant research records were first reviewed to compile a list of drivers in the development of convergent technologies. The list was then refined and prioritized to identify two key drivers, with the Delphi process attended by fourteen experts. By intersecting the uncertainties of these two drivers, four scenarios of the province's future in technological CONVERGENCE competition emerged. Findings: The two key drivers affecting the success of the province in the competition for convergent technologies are: the rate of development of the innovation ecosystem and the amount of financial resources allocated to this process. Based on this, four scenarios of the future situation of the province in this field were identified, which have been named as "Vanguard", "Buyer", "Remnant" and "Hired". Conclusion: In order for the provinces to be able to succeed in the forthcoming competitions in the production and operation of convergent technologies, it is necessary to plan for strengthening the ecosystem infrastructure from now; at the same time, it is necessary to make efficient efforts to provide sufficient financial resources for the research and commercialization of these technologies.

Introduction: Different factors can affect the retention of full veneer crowns such as clinical length of crown, diameter of tooth, angle of CONVERGENCE, type of restoration and the cement. The aim of this study was assessment of the CONVERGENCE ANGLES of tooth preparations for full coverage crown among dentistry students.Methods and materials: In this observational- cross sectional study, 210 dies from prepared anterior and posterior teeth by under graduate and postgraduate students were randomly selected. In the two groups, the mesiodistal and buccolingual ANGLES of the dies were measured with stereomicroscope and moticam camera and compared with each other. The results were analyzed by t-test via SPSS- 11.5 software.Results: The total average CONVERGENCE angle was 23.8 ± 8.6 degrees for the preparations performed by undergraduate students and 22.4 ± 9.0 for postgraduate group. The average CONVERGENCE angle for anterior preparations was 24.4 ± 8.1 degrees in undergraduate group and 20.2 ± 7.7 degrees in postgraduate group and for posterior preparations it was 23.6 ± 8.8 degrees in under graduate group and 24.1 ± 9.6 degrees in other group. Differences in CONVERGENCE ANGLES of anterior preparations between two groups were significant (p value = 0.02), but for posterior preparations and other preparation were not statistically significant.Conclusion: The total average CONVERGENCE angle of all preparations and posterior preparations in two groups were the same, But it was significantly greater in anterior preparations prepared by undergraduate students. In any case, the findings were similar to some of previous studies.

Face recognition from digital images is used for surveillance and authentication in cities, organizations, and personal devices. Internet of Things (IoT)-powered face recognition systems use multiple sensors and one or more servers to process data. All sensor data from initial methods was sent to the central server for processing, raising concerns about sensitive data disclosure. The main concern was that all data from all sectors that could contain confidential information was placed in a central server. Federated learning can solve this problem by using several local model training servers for each region and a central aggregation server to form a global model in IoT networks. This article presents a novel approach to optimize data transfer and CONVERGENCE time in federated learning for a face recognition task using Non-dominated Sorting Genetic Algorithm II (NSGA II). The aim of the study is to balance the trade-off between training time and model accuracy in a federated learning environment. The results demonstrate the effectiveness of the proposed approach in reducing data transfer and CONVERGENCE time, leading to improved performance in face recognition accuracy. This research provides insights for researchers and practitioners to enhance the efficiency of federated learning in real-world applications.

Background and aim: Mechanical fracture is a common cause for the failure of three-unit dental bridges, particularly the all-ceramic ones.The goal of the present study was to evaluate the effects of convergent ANGLES of the abutments on the peak and distribution of mechanical stresses within the prosthesis and at the restoration abutment interface of a three-unit all-ceramic bridge using finite element method.Materials and Methods: The cloud points of three-D geometrical data of the second premolar and first and second molar teeth were obtaind using ATOS Scanner system and utilized for the reconstruction of a surface model of the three-unit bridge in CATIA software. Data were than transferred to I-DEAS software for mesh generation and finite element analysis. Two EF models were developed with convergent ANGLES corresponding to the up and low defined range including 171900 and 168700 tetraherdal solid four-node elements, respectively.The models were subjected to two different prosthesis materials and three different load cases.Results: The maximum tensile stresses occurred on the gingival surface of the second premolar retainer and at the tooth/restoration interface on the marginal distal surface of the second molar abutment. The peak tensile stress was relatively lower for the model with the higher convergent angle but the difference was not significant. Changing the prosthesis material from IE2 to Dicor decreased the stresses within the prosthesis.Conclusion: Higher safety factor was found for IE2 due to its higher mechanical strength. Moreover, it was proved that load condition played an important role on the mechanical stress observed.

Glaucoma is the leading cause of irreversible blindness worldwide. Among all glaucoma types, primary angle closure glaucoma (PACG) affects approximately 23 million people worldwide, and is responsible for 50% of glaucoma-related blindness, highlighting the devastating consequences of this disease. The main mechanism of PACG is relative pupillary block. High-risk populations are female gender, Asian ethnicity, high hyperopia, short axial length, and a thick/anteriorly positioned lens. This review discusses the clinical diagnosis, classification, and management of patients with a narrow angle with and without intraocular pressure (IOP) elevation and glaucomatous optic nerve damage, including laser peripheral iridotomy (LPI), endocycloplasty (ECPL), lens extraction, and goniosynechialysis.