Search results for "Tukey's range test"
showing 10 items of 10 documents
In vitro effectiveness of different endodontic irrigants on the reduction of Enterococcus faecalis in root canals
2010
Objective: To compare the reduction of E. faecalis counts in root canals produced by irrigation with distilled water, hydrogen peroxide, sodium hypochlorite, chlorhexidine, and combinations of solutions, in vitro. Study Design: Study sample included sixty mandibular premolar teeth mounted in dental stone. Root canals were prepared using crown down technique under distilled water irrigation. Specimens were sterilized overnight by ethylene oxide gas. Each canal was completely filled up with the E. faecalis suspension and incubated at 37ºC for 24 hours. Root canals were irrigated with the test solutions. A volume of 5 ml of the tested irrigant was used for each sample with an exposure period o…
Flexural strength and microhardness of anterior composites after accelerated aging
2016
Background This study aimed to evaluate the flexural strength and microhardness of three different anterior composites after 10 000 thermocycles. Material and Methods The mechanical properties of a nano-fill composite (Filtek Ultimate Universal Restorative (FUR) (Enamel)), a nano-hybrid composite (Clearfil Majesty ES2 (ES2) (Enamel)), and a micro-hybrid composite (G Aenial Anterior (GAA)) were investigated in this study. For the microhardness test, 8-mm diameter and 2-mm thickness composite discs were used (n = 10), and for the flexural strength test, 25x2x2 mm bar-shaped specimens were prepared (n = 13). The specimens were tested at 24 h and after 10 000 thermocycles. Data were analyzed us…
In vitro analysis of the pH stability of dental bleaching gels during in-office procedures
2021
Background Previous studies have shown that acidic bleaching gels could lead to worse collateral effects during an in-office bleaching procedure, while neutral or basic products leads towards a better experience. Considering this fact, the main purpose of this study was to evaluate the pH behavior of 6 in-office bleaching gels, compared to the information provided by their manufacturers. Material and methods Thirty enamel discs of bovine teeth were prepared, the initial colors of which were measured by a spectrophotometer and then divided into 6 groups. A pH meter was used to measure the pH every 30 seconds until the end of each procedure, when a new color evaluation was then made. The Tuke…
Effect of different solutions in reversing the damage caused by radiotherapy in dentin structure
2020
Background Previous studies have shown that radiotherapy of the head and neck region can cause direct changes in dental structure. This study evaluated the effect of different solutions on the dentin chemical composition and collagen structure of irradiated dentin. Material and Methods Sixty maxillary canines were distributed in 2 groups (n=30): non-irradiated and irradiated (radiotherapy: X-rays of 6 MV in 30 cycles of 2 Gy to 60 Gy). The teeth were sectioned, sanded, and polished to obtain 3x3x2 mm fragments, which were redistributed in 3 subgroups (n=10) according to the treatment employed: chlorhexidine 2% (CL), chitosan 0.2% (QT), and 0.5 M carbodiimide (EDC). The samples were analyzed…
Effect of alkaline ph on sealing ability of white mineral trioxide aggregate
2011
Objectives: The aim of this study was to evaluate microleakage of white mineral trioxide aggregate (WMTA) after its exposure to a range of alkaline environments during hydration. Study Design: Seventy single-rooted teeth were divided into 4 experimental and 2 control groups. All the teeth were instrumented, and their apices were resected. Root-end cavities were filled with WMTA in the experimental groups. In the control groups, root-end cavities were not filled. Root-end fillings were exposed to alkaline environments with pH values of 7.4, 8.4, 9.4, or 10.4 for 3 days. Microleakage was evaluated by bovine serum albumin. Evaluations were carried out at 24-hour intervals for 80 days. Data wer…
Solubility and pH of bioceramic root canal sealers: A comparative study
2017
Background This study compared the solubility and the pH of different root canal sealers in vitro. Material and Methods BioRoot™RCS, TotalFill BC Sealer, MTA Fillapex, SealapexTM, AH Plus, EasySeal, Pulp Canal Sealer™ and N2 were tested. Similar specimens were prepared using ring molds with an internal diameter of 20 ± 0,1 mm and a height of 1,5 ± 0,1 mm and digitally weighted to register the mass of each specimen before and after immersion in distilled water. Solubility was determined after 24 hours and statistically analysed using a one-way ANOVA test and post-hoc Tukey test. The pH value was measured by a digital pH meter after 3 and 24 hours from manipulation. Results BioRoot™RCS and To…
Correlation between alteration of enamel roughness and tooth color
2018
Background To establish the correlation between enamel roughness and color change of tooth. Material and Methods Enamel/dentin blocks (5 x 5 x 3.2 mm) were serially ground with the following abrasive paper: 1200-grit, 800-grit, and 600-grit SiC papers. In the paired model, the analyses of color (L*, a*, b*, ΔE) and roughness (Ra) were performed among the sandpaper exposure. The data were subjected to ANOVA using models for repeated measures followed by the Tukey test. The Pearson correlation test was used to determine whether there was a relationship between Ra values and color results (α = 0.05). Results The L* values decreased in accordance with the increase of Ra, with statistical differ…
Dimensional stability of contemporary irreversible hydrocolloids: humidor versus wet tissue storage.
2012
Statement of problem The storage time and conditions of irreversible hydrocolloid impressions affect their accuracy and in turn the precision of the definitive cast. Recommendations for proper storage are, however, based on theoretical assumptions rather than facts. Purpose The purpose of this study was to assess the influence of the 2 most common storage conditions on the dimensional stability of 7 contemporary irreversible hydrocolloids (IH) for a period of up to 7 days. Material and methods Twelve specimens per material (Blueprint, Cavex CA37, Cavex ColorChange, Jeltrate, Orthoprint, Cavex Orthotrace, and Tetrachrom) were fabricated according to ISO/CD 21563. The specimens were either st…
Stress distribution in fixed mandibular prostheses fabricated by CAD/CAM and conventional techniques: Photoelastic and strain gauge analyses
2019
Made available in DSpace on 2020-12-12T00:55:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-09-01 The aim of this study was to evaluate the distribution of stress in complete fixed mandibular prostheses with infrastructures (IE) fabricated with different materials and techniques, under compressive force. A model of an edentulous mandible, which received five 4x11 mm external hexagon implants between the mental foramens, was fabricated. The groups were divided into: Group I - IE in nickel-chromium with an acrylic resin occlusal coating; Group II - IE in nickel-chromium with a ceramic occlusal coating; Group III - IE milled in zirconia with a ceramic coating. For the photoelastic m…
Effect of two different tooth bleaching techniques on microhardness of giomer
2016
Background Tooth bleaching is a safe and conservative treatment modality to improve the esthetic appearance of discolored teeth. One of the problems with the use of bleaching agents is their possible effect on surface microhardness of resin-based materials. The present study was carried out to evaluate the effect of in-office and at-home bleaching on surface microhardness of giomer. Material and Methods Seventy-five disk-shaped giomer samples (Beautifil II) were prepared and cured with a light-curing unit. The samples were randomly assigned to three groups (n=25). In group 1 (control), the samples were stored in distilled water for 14 days. The samples in groups 2 and 3 underwent a bleachin…