ABSTRACT
This study investigated the influence of mechanical cycling on screwed-in and tappedin implants restored with screw-retained metallic crowns. Three implant-abutmentcrown systems were evaluated: T1 (multi abutment) and T2 (standard abutment) received tapped-in abutments and S received a screwed-in abutment. The specimens were subjected to two million cycles of 0-150 N load, at 2 Hz, 30° inclination in a dry medium, and torque evaluation. Survival and removal torque were analyzed using chisquare, ANOVA, followed by Tukey's test. Differences between installation and removal torque were determined using a T-test for dependent samples. Analyses were performed in SPSS, considering α = 0.05. All specimens survived mechanical cycling in S, 40% in T1, 80% in T2 (p=0.008). Failures occurred due to loosening of the crown screw. A significant decrease in torque (p=0.000) was found. Group T1 had the lowest removal torque (1.6 ± 0.84 N.Cm²), followed by T2 (3 ± 1.49 N.Cm²) and S (6.3 ± 1.16 N. Cm²), and a statistical difference was found between Groups T1 and S. Both types of implantabutment connections were stable and can be considered for rehabilitative treatment, but failure and removal torque were influenced by the design of prosthetic abutment. Crowns were more susceptible to becoming loose in tapped-in systems.
Subject(s)
Dental Implant-Abutment Design , Dental Implants , Torque , Dental Abutments , Dental Stress Analysis , Crowns , Bone Screws , Materials TestingABSTRACT
BACKGROUND AND AIMS: Introduction: The familial hypercholesterolemia (FH) is one of the main causes of cardiovascular diseases, and it is mainly caused by genetic variants at the low-density lipoprotein receptor (LDLR). Although ultrasequencing technology has allowed the identification of several genetic variants, few of them was functional analyzed. The CRISPR/ Cas9 tool promotes precise genetic editing and allows the creation of experimental models, therefore contributing to the functional validation process. Aim: To use the CRISPR/Cas9 tool to perform in vitro functional analysis of LDLR variants identified in FH patients. METHODS: Two missense LDLR variants were selected within a group of variants identified in FH patients, based on in silico data, the affected protein domain and MAF. Three sgRNAs were designed for each of the variants c.551G>A and c.1118G>A, to analyze the accuracy of the sgRNAs. The sgRNAs were inserted on PX458 plasmid, cloned, purified in E. coli DH5a, and then co-transfected with the DNA template at HepG2 cells. The DNAs templates were designed to contain the selected variants. RESULTS: HepG2 cells co-transfected with PX458 constructs and DNA templates showed considerably transfection rate, being possible to visualize it at fluorescence microscopy. However, it was noted that single transfection of sgRNAs showed a higher transfection efficiency than cotransfection. CONCLUSIONS: We designed sgRNA for c.551G>A and c.1118G>A variants, being able to analyze the transfection efficiency. In further steps, we will select new sgRNAs for LDLR variants that have not been described yet, and functional analysis will be performed to determine the clinical relevance of these variants.
Subject(s)
Hyperlipoproteinemia Type II , Lipids , Lipoproteins, HDL , GeneticsABSTRACT
The Education for All Handicapped Children Act of 1975, PL 94-142, will cause mildly handicapped children to be integrated into mainstream academic classes including health education. Because of the disparate needs of these children, health educators will have to provide for a diverse group of learners. Since it is clear that health education encompasses topics crucial to the overall social and personal development of the handicapped, it is essential that health educators become prepared to maximize learning opportunities for the handicapped child in the mainstream.
