Search results for "Operative dentistry"
showing 10 items of 204 documents
Fracture resistance of tooth restored with four glass fiber post systems of varying surface geometries-An in vitro study
2016
Background The purpose of this study was to relate the fracture resistance of endodontically treated teeth in relation to post geometry. Material and methods Forty single rooted mandibular premolars were instrumented by step - back technique and obturated by lateral condensation. Forty teeth were randomly divided into four groups: Reforpost glass fiber X-ray®, RelyX®, Exacto conical® and Parapost Fiber Lux®. The post spaces were prepared using respective drills and luted. The core build up was done and metal crowns were luted. Fracture resistance was determined in universal testing machine. The statistical analysis was done using one way ANOVA and post hoc Tukey Kramer test. Results The tee…
Effect of different polishing techniques on surface roughness and bacterial adhesion of three glass ionomer-based restorative materials : in vitro st…
2020
Background Although many reports concluded that polishing of glass ionomers is crucial for smoother surface and limiting the adhesion of cariogenic bacteria, there is no specific surface treatment protocol recommended. A novel material in the same category was released recently claimed to have surface smoothness comparable to resin composite and bacterial adhesion less than other types of glass ionomers. In this study, different polishing systems were tested with three glass ionomers one of them is the novel material to find the most appropriate polishing protocol. Objectives: To evaluate and compare the surface roughness and bacterial adhesion to resin modified glass ionomer, bioactive ion…
Intensity output and effectiveness of light curing units in dental offices
2018
Background The aims of the study were measuring the light intensity of light curing units used in Qazvin's dental offices, determining the relationship between the clinical age of these units and their light intensity, and identifying the reasons for repairing them. Material and Methods In this cross-sectional study, the output intensity of 95 light curing devices was evaluated using a radiometer. The average output intensity was divided up into four categories (less than 200, 200-299, 300-500, and more than 500 mW/cm2). In addition, a questionnaire was designed to obtain information mainly about the type, clinical age, and frequency of maintenance of the units and the reasons for fixing th…
Influence of different thermopolymerization methods on composite resin microhardness
2020
Background Additional heat polymerization in composite resins allows greater effectiveness of microhardness, flexural strength, fracture toughness, wear resistance, and increased color stability. Material and Methods 150 composite resin specimens were made using a 4 mm diameter and 2 mm thick bipartite steel matrix. Five resins composed of different compositions were tested (Brilliant Everglow/Coltene, Filtek One BulkFill/3M, Filtek P60/3M, Filtek Z350XT/3M, Filtek Z250XT/3M), and for each of them three types of polymerization were tested: light curing only (n=50); photopolymerization + autoclave thermopolymerization (n=50) and photopolymerization + microwave thermopolymerization (n=50). …
The effect of short polyethylene fiber with different weight percentages on diametral tensile strength of conventional and resin modified glass ionom…
2017
Background The aim of this study was to investigate the effect of polyethylene fiber on diametral tensile strength of conventional and resin modified glass ionomer cements. Material and Methods 60 specimens in 6 groups (n=10) were prepared. In group 1 conventional glass ionomer (Fuji GC) and in group 2 resin modified glass ionomer (Fuji LC) were as control groups. In group 3 and 4 conventional glass ionomers mixed with short polyethylene fibers in proportion of 1 wt% and 3 wt%, respectively. In fifth and sixth groups, resin modified glass ionomer and short polyethylene fibers were mixed in 1 and 3% wt, respectively. Samples were prepared in a round brass mold (6.5×2.5 mm). After thermo-cycl…
Comparison between the effect of adding microhydroxyapatite and chitosan on surface roughness and Microhardness of resin modified and conventional gl…
2019
Background This study aimed to compare the effect of chitosan (CH) and hydroxyapatite (HP) on the surface roughness and microhardness of a conventional glass ionomer cement (CGIC) and a resin modified glass ionomer cement (RMGIC). Material and Methods 60 disk-shaped specimens (2mm x 6mm) were prepared in 6 groups; group I: CGIC, group II: RMGIC, group III: CGIC + 15% volume CH solution in liquid, group IV: CGIC +10% weight micro-HP in powder, group V: RMGIC + 15% volume CH, group VI: RMGIC + 10% weight micro-HP. After storage in deionized water at room temperature for 24 hours, the surface roughness and microhardness of the specimens were measured using a surface profilometer and Vickers mi…
Effect of resin thickness, and curing time on the micro-hardness of bulk-fill resin composites
2015
Background: Bulk-fill resin composite has been introduced, their manufacturers claimed that they can be applied in bulks of 4mm, without necessitating a prolonged curing time, or a light curing unit with increased irradiance. Thus this study was conducted to evaluate the effect of resin thickness, and curing time on the micro-hardness of two bulk -fill resin composites; Tetric Evo-Ceram [TE], and X-trafil [XF]. Material and Methods: 120 cylindrical specimens were prepared, and divided into 24 groups (n=5/group), representing the two bulk-fill resin composites, three different material thicknesses (2, 3 and 4 mm) and the four curing times used in the study (10, 20, 40, and 60 seconds). The s…
Efficacy of three methods for inserting calcium hydroxide-based paste in root canals
2017
BACKGROUND: To compare the quality of calcium hydroxide paste fillings performed by three different techniques. MATERIAL AND METHODS: Sixty extracted maxillary central incisors, with previous root canal treatment, were decoronated and the gutta-percha was completely removed from the root canals. Subsequently, the canals were filled with a calcium hydroxide-based paste composed of calcium hydroxide, bismuth carbonate, and glycerin. The study samples were divided into the following three groups on the basis of three insertion techniques (n = 20, each): conventional technique using a hand instrument (MAN), rotary Lentulo spiral (LEN) technique, and a combined technique combining conventional h…
Effect of root canal rinsing protocol on dentin bond strength of two resin cements using three different method of test
2015
Background Different studies have used different tests to evaluate bond strength of resin cements to root dentin. In this in vitrostudy, three different tests were used to evaluate the bond strength of two resin cements to root dentin using two root dentin irrigation protocols. Material and Methods Ninety-six intact single-rooted teeth were selected for this study. Forty-eight teeth, with a root length of 15mm, were randomly divided into two groups and irrigated with normal saline or 2.5% sodium hypochlorite solutions during root canal preparation, respectively. For each 12 specimens from each group, fiber post #1 was bonded using an etch-and-rinse (Duo-Link) and a self-adhesive (BisCem) re…
Effect of the several epoxy resin-based sealer compositions on adhesion interface in radicular dentin after calcium hydroxide intracanal medication r…
2021
Made available in DSpace on 2022-04-29T08:32:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-09-01 Background: This study evaluated the effects of several epoxy resin-based sealer compositions (AHP, AH Plus; ADS, Adseal; SPL, Sealer Plus) on bond strength and intratubular dentin penetration of the endodontic obturation, in root canal previously treated with calcium hydroxide intracanal medication (CH) and removed by continuous ultrasonic irrigation (CUI). Material and Methods: Forty-five maxillary canines were prepared up to F5 (ProTaper system), filled with CH, coronally sealed, and stored at 37ºC. After 1 week, CH was removed using 2.5% sodium hypochlorite energized by CUI. The …