Αρχειοθήκη ιστολογίου

Τετάρτη 20 Ιουλίου 2022

Fatigue resistance and fracture strength of narrow‐diameter one‐piece zirconia implants with angled abutments

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Abstract

Objective

Zirconia implants are assumed to satisfy the esthetic requirements that titanium implants cannot meet, however, there are not enough studies in the literature about narrow-diameter and angled zirconia implants that can be preferred especially in the anterior region. This in vitro study aimed to evaluate the fatigue resistance and fracture strength of narrow-diameter zirconia implants with angled abutments.

Materials and Methods

Forty-eight one-piece experimental zirconia implants and monolithic zirconia crowns were produced from 3-YTZP blanks. The implant diameters (3.0 or 3.7 mm) and the restoration types were determined according to three intraoral regions (upper central incisors, lower central incisors, and upper canine), and abutments were designed as straight or 15° angled. The samples were subjected to chewing simulation corresponding to 5 years of clinical performance and then the static loading test. The survival rates of groups were measured by the Kaplan–Meier log-rank test, and the fracture load values were estimated by using Kruskal–Wallis and Mann–Whitney U tests (p < 0.05).

Results

All 3.0 mm diameter implants failed the fatigue test. The fatigue resistance of the implants with angled abutments was significantly lower than the straight abutments, and different crown designs were found to affect survival rates significantly. The fracture strengths of the surviving groups were above the maximum physiological chewing forces, and the differences were not significant.

Conclusions

The implant diameter, abutment angle, and restoration type have a significant effect on the fatigue behavior of zirconia implants.

Clinical Significance

The fracture strengths of the one-piece zirconia implants with a 3.7 mm diameter and a 15° abutment angle are above the chewing forces for the anterior intraoral region.

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Safety and efficacy of molnupiravir in SARS‐CoV‐2 infected patients: a real‐life experience

alexandrossfakianakis shared this article with you from Inoreader

Abstract

Introduction

Since the start of the SARS-CoV-2 pandemic, several treatments have been proposed to cure Coronavirus Disease 2019 (COVID-19) and prevent it. Molnupiravir is a ribonucleoside prodrug of N-hydroxycytidine with an in vitro e in vivo activity against SARS-CoV-2.

Methods

We conducted a retrospective cohort study including all people treated with Molnupiravir between the 10th of January and the 31th of March 2022 at the University Hospital of Sassari. Molnupiravir was prescribed, according to the Italian Agency of Drug indications, in patients with recent symptoms onset (≤5five days), no need of oxygen supplementation, and with a high risk of disease progression for the presence chronic diseases.

Results

We included 192 people with a mean age of 70.4±15.4 years; 144 (75%) patients were over 60 years. During the follow-up, 20 (10.4%) patients showed a disease progression. At the multivariate analysis, older age, having neurological dis ease, and having dyspnea at the onset of the symptoms, and acquiring SARS-CoV-2 infeciton during an hospital admission were associated with an increased risk of progression. On the contrary, early start of treatment was associated with a reduced risk of disease progression. Molnupiravir was also extremely safe since 13 (6.8%) adverse events were reported, with only one interruption.

Conclusion

Our study shows that Monlupiravir confirmed its efficacy and safety in a real-life cohort that included a high percentage of elderly people with a high comorbidity burden.

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A Comparative Study Assessing the Precision and Trueness of Digital and Printed Casts Produced From Several Intraoral and Extraoral Scanners in Full Arch and Short Span (3‐Unit FPD) Scanning: An In Vitro Study

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ABSTRACT

Purpose

: To compare precision and trueness of digital and printed casts produced from several intraoral and extraoral scanners in full arch and short span scanning.

Materials and Methods

: A fully dentate maxillary phantom cast was used to represent full arch scanning, and a mandibular phantom cast including posterior 3-unit fixed partial denture (FPD) preparations to represent short span scanning. Reference casts (RC) were fabricated and scanned 10 times by a reference extraoral scanner (Medit T510, Seoul, Korea) to provide reference digital casts (RD). RC was then scanned 10 times by 5 scanners: 2 intraoral scanners (Trios 3shape (Trios 3) and Dental Wings (DW)), and 3 extraoral scanners (3shape E3 (E3), S600 ARTI (S600), and Ceramill Map 600 (M600)). Digital STL files obtained from the 5 scanners were sent to a stereolithography 3D printer to fabricate printed casts. Trueness was obtained by comparing STL files of each digital/printed cast to the RC, while precision was obtained by comparing the digital/printed STL file of each scanner to the other files of same digital/printed group. The lower the precision and trueness values, the higher the accuracy of casts . Multivariate Analysis of Variance was performed to assess the association of precision and trueness with the type of scanner, type of cast, and scanning span.

Results

: There was a significant difference in precision and trueness of casts produced from different scanners (p <0.001). The lowest precision and trueness were demonstrated by casts produced from DW. Digital casts showed significantly higher precision and trueness compared to 3D printed casts (p <0.001). Regarding the scanning span, full arch scanning showed significantly lower precision and trueness than short span scanning (p <0.001).

Conclusions

: Extraoral scanners exhibited higher trueness and precision than intraoral scanners. Trios 3 showed comparable accuracy to that of the studied extraoral scanners in the case of short span scanning. DW was the least accurate scanner in all studied groups, while E3 showed the highest accuracy level among the mentioned scanners. Digital casts showed higher trueness and precision compared to 3D printed casts.

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Tracking and recording the lip dynamics for the integration of a dynamic virtual patient: A novel dental technique

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Abstract

A step-by-step technique for tracking and recording in real-time the lip dynamics of the patient and for integrating this lip dynamics into the 3D virtual patient representation by using facial trackers and motion engine software programs is described. The main advantage of this technique is that it enables capturing of the lip movements of the patient in real time; therefore, the lip movements are not simulated from a previously recorded video of the patient by using animation software programs.

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Understanding spatio-temporal human mobility patterns for malaria control using a multi-agent mobility simulation model

alexandrossfakianakis shared this article with you from Inoreader

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ABSTRACT
Background
More details about human movement patterns are needed to evaluate relationships between daily travel and malaria risk at finer scales. A multi-agent mobility simulation model was built to simulate the movements of villagers between home and their workplaces in two townships in Myanmar.
Methods
An agent-based model (ABM) was built to simulate daily travel to and from work based on responses to a travel survey. Key elements for the ABM were lan dcover, travel time, travel mode, occupation, malaria prevalence, and a detailed road network. Most visited network segments (MVS) for different occupations and for malaria-positive cases were extracted and compared. Data from a separate survey was used to validate the simulation.
Results
Mobility characteristics for different occupation groups showed that while certain patterns were shared among some groups, there were also patterns that were unique to an occupation group. Forest workers were estimated to be the most mobile occupation group, and also had the highest potential malaria exposure associated with their daily travel in Ann Township. In Singu Township, forest workers were not the most mobile group; however, they were estimated to visit regions that had higher prevalence of malaria infection over other occupation groups.
Conclusions
Using an ABM to simulate daily travel generated mobility patterns for different occupation groups. These spatial patterns va ried by occupation. Our simulation identified occupations at a higher risk of being exposed to malaria and where these exposures were more likely to occur.
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Differential survival of potentially pathogenic, septicemia- and meningitis-causing E. coli across the wastewater treatment train

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Pediatric hematology providers’ contraceptive practices for female adolescents and young adults with sickle cell disease: A national survey

alexandrossfakianakis shared this article with you from Inoreader

Abstract

Background

Adolescent and young adult (AYA) women with sickle cell disease (SCD) have increased pregnancy-related health risks and are prescribed potentially teratogenic medications, yet limited data are available regarding pediatric SCD provider contraceptive practices. We aimed to assess pediatric hematology providers' beliefs, practices, motivators, and barriers for providing contraceptive care to female AYAs with SCD.

Methods

Guided by the Health Belief Model (HBM), we developed a 25-question, web-based survey to assess practices. Survey links were distributed nationwide to pediatric SCD and/or general hematology providers through their publicly available emails and by request to directors of U.S.-accredited Pediatric Hematology-Oncology fellowship programs for distribution to their SCD providers. Data analysis included descriptive statistics, chi-square analysis, and logistic regression.

Results

Of 177 respondents, 160 surveys meeting inclusion criteria were analyzed. Most providers reported counseling (77.5%) and referring female AYA patients for contraception (90.8%), but fewer reported prescribing contraception (41.8%). Proportionally fewer trainees provided counseling compared with established providers (54% vs. 85%, p < .001), with a similar trend for prescribing (p = .05). Prescription practices did not differ significantly by provider beliefs regarding potential teratogenicity of hydroxyurea. Key motivators included patient request and disclosure of sexual activity. Key barriers included inadequate provider training, limited visit time, and perceived patient/parent interest.

Conclusion

Provider contraceptive practices for female AYAs with SCD varied, especially by provider status. Health beliefs regarding teratogenic potential of hydroxyurea did not correlate with contraceptive practices. Clinical guidelines, provider training, and patient/parent decision-making tools may be tested to assess whether provider contraceptive practices could be improved.

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