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Noor Hayaty Abu Kasim Abu Kasim N.H.

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Full-Text Articles in Dental Public Health and Education

Performance Of Melamine Modified Urea-Formaldehyde Microcapsules In A Dental Host Material, Noor Hayaty Abu Kasim Abu Kasim N.H. Nov 2011

Performance Of Melamine Modified Urea-Formaldehyde Microcapsules In A Dental Host Material, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

Urea-formaldehyde (UF) microcapsules filled with dicyclopentadiene (DCPD) show potential for making self-healing dental restorative materials. To enhance the physical properties of the capsules, the urea was partially replaced with 0-5% melamine. The microcapsules were analyzed by different microscopic techniques. DSC was used to examine the capsule shell, and the core content was confirmed by (1)H NMR spectroscopy. Capsules in the range of 50-300 mu m were then embedded in a dental composite matrix consisting of bisphenol-A-glycidyl dimethacrylate (Bis-GMA) and triethylene-glycol dimethacrylate (TEGDMA). Flexural strength, microhardness, and nanoindentation hardness measurements were performed on the light-cured specimens. Optical microscopy (OM) examination showed …

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Human Platelet Lysate Permits Scale-Up Of Dental Pulp Stromal Cells For Clinical Applications, Noor Hayaty Abu Kasim Abu Kasim N.H. Nov 2011

Human Platelet Lysate Permits Scale-Up Of Dental Pulp Stromal Cells For Clinical Applications, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

Background aims. Dental pulp stromal cells (DPSC) are considered to be a promising source of stem cells in the field of regenerative therapy. However, the usage of DPSC in transplantation requires large-scale expansion to cater for the need for clinical quantity without compromising current good manufacturing practice (cGMP). Existing protocols for cell culturing make use of fetal bovine serum (FBS) as a nutritional supplement. Unfortunately, FBS is an undesirable additive to cells because it carries the risk of transmitting viral and prion diseases. Therefore, the present study was undertaken to examine the efficacy of human platelet lysate (HPL) as a …

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Development Of Craniofacial Implants Produced By Metal Injection Molding Of Titanium Alloy Using Novel Binder System Based On Palm Oil, Noor Hayaty Abu Kasim Abu Kasim N.H. Oct 2011

Development Of Craniofacial Implants Produced By Metal Injection Molding Of Titanium Alloy Using Novel Binder System Based On Palm Oil, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

Metal Injection Molding (MIM) is a cost-effective technique for producing small, complex, precision parts in high volumes. MIM consists of four main processing steps: mixing, injection molding, debinding and sintering. In the mixing step, the powder titanium alloy (Ti6Al4V) medical grade is mixed with a binder system based on palm stearin to form a homogeneous feedstock. The rheological studies of the feedstock have been determined properly in order to success during injection into injection molding machine. After molding, the binder holds the particles in place. The binder systems then have to be removed completely through debinding step. Any contamination of …

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Porosity Reduction Model In Titanium - Hydroxyapatite Fgm Composites Using Shrinkage Measurement, Noor Hayaty Abu Kasim Abu Kasim N.H. Aug 2011

Porosity Reduction Model In Titanium - Hydroxyapatite Fgm Composites Using Shrinkage Measurement, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

A multilayered titanium (Ti)‐hydroxyapatite (HA) functionally graded material was produced via pressureless sintering at 1100°C. The initial and final porosities were determined via shrinkage measurements. The final porosity verification was carried out by the Archimedes method. The experimental porosity measurements were compared with two proposed models. The macroscopic and microstructure features and the measured porosities confirmed that the volume fraction porosity was associated with both matrix and reinforcing particles in all cases. The percolation threshold was observed at x = 0·75 in the xTi+(1−x)HA mixture.

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Differentiation Of Dental Pulp Stem Cells Into Islet-Like Aggregates, Noor Hayaty Abu Kasim Abu Kasim N.H. May 2011

Differentiation Of Dental Pulp Stem Cells Into Islet-Like Aggregates, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

The post-natal dental pulp tissue contains a population of multipotent mesenchymal progenitor cells known as dental pulp stromal/stem cells (DPSCs), with high proliferative potential for self-renewal. In this investigation, we explored the potential of DPSCs to differentiate into pancreatic cell lineage resembling islet-like cell aggregates (ICAs). We isolated, propagated, and characterized DPSCs and demonstrated that these could be differentiated into adipogenic, chondrogenic, and osteogenic lineage upon exposure to an appropriate cocktail of differentiating agents. Using a three-step protocol reported previously by our group, we succeeded in obtaining ICAs from DPSCs. The identity of ICAs was confirmed as islets by dithiozone-positive …

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Differentiation Of Dental Pulp Stem Cells Into Islet-Like Aggregates, Noor Hayaty Abu Kasim Abu Kasim N.H. Apr 2011

Differentiation Of Dental Pulp Stem Cells Into Islet-Like Aggregates, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

The post-natal dental pulp tissue contains a population of multipotent mesenchymal progenitor cells known as dental pulp stromal/stem cells (DPSCs), with high proliferative potential for self-renewal. In this investigation, we explored the potential of DPSCs to differentiate into pancreatic cell lineage resembling islet-like cell aggregates (ICAs). We isolated, propagated, and characterized DPSCs and demonstrated that these could be differentiated into adipogenic, chondrogenic, and osteogenic lineage upon exposure to an appropriate cocktail of differentiating agents. Using a three-step protocol reported previously by our group, we succeeded in obtaining ICAs from DPSCs. The identity of ICAs was confirmed as islets by dithiozone-positive …

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Structural And Compositional Characterization Of Silverfil Amalgam, Noor Hayaty Abu Kasim Abu Kasim N.H. Mar 2011

Structural And Compositional Characterization Of Silverfil Amalgam, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

SilverFil (Silverfildental Products, Malaysia) is another commercially available dental amalgam; however it is based on silver and mercury only. It is claimed that upon amalgamation, there is no excess mercury in SilverFil. Objectives: The objectives of this study were to determine the structural state and chemical composition of the starting materials and presence of mercury in the resulting amalgam. Methods: All the starting materials of SilverFil and the SilverFil amalgam specimens were characterize using Field Emission Scanning Electron Microscopy (FESEM-EDX), X-Ray Diffraction (XRD) and X-Ray Photoelectron Spectroscopy (XPS). Results: The FESEM images of the amalgam shows silver-mercury (Ag-Hg) clusters. The …

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Optimization Of Microencapsulation Process For Self-Healing Polymeric Material, Noor Hayaty Abu Kasim Abu Kasim N.H. Jan 2011

Optimization Of Microencapsulation Process For Self-Healing Polymeric Material, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

A series of poly(urea-formaldehyde) (PUF) microcapsules filled with dicyclopentadiene (DCPD) was successfully prepared by in situ polymerization. The effect of diverse process parameters and ingredients on the morphology of the microcapsules was observed by SEM, optical microscopy (OM) and digital microscopy. Different techniques for the characterization of the chemical structure and the core content were considered such as FT-IR and (1)H-NMR as well as the characterization of thermal properties by DSC. High yields of free flowing powder of spherical microcapsules were produced. The synthesized microcapsules can be incorporated into another polymeric host material. In the event the host material cracks …

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3d-Fe Analysis Of Functionally Graded Structured Dental Posts, Noor Hayaty Abu Kasim Abu Kasim N.H. Dec 2010

3d-Fe Analysis Of Functionally Graded Structured Dental Posts, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

This study aimed to compare the biomechanical behaviour of functionally graded structured posts (FGSPs) and homogenous-type posts in simulated models of a maxillary central incisor. Two models of FGSPs consisting of a multilayer xTi-yHA composite design, where zirconia and alumina was added as the first layer for models A and B respectively were compared to homogenous zirconia post (model C) and a titanium post (model D). The amount of Ti and HA in the FGSP models was varied in gradations. 3D-FEA was performed on all models and stress distributions were investigated along the dental post. In addition, interface stresses between …

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Thermo-Mechanical Stress In Multilayered Dental Post Due To Temperature Gradient, Noor Hayaty Abu Kasim Abu Kasim N.H. Sep 2010

Thermo-Mechanical Stress In Multilayered Dental Post Due To Temperature Gradient, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

Objective: To analyse thermo-mechanical stress in endodontically treated teeth restored with Multilayered Structured Dental Posts (MSDPs) under cold and hot conditions using Finite Element Analysis (FEM). Methods: Three MSDPs of multilayer design of xTi-yHA composition added to a zirconia layer (model A), an alumina layer (model B) and a titanium layer (model C) were compared with zirconia (model D) and titanium (model E) posts. The fractions of Ti and HA was varied gradually. Changes in temperature of an endodontically restored tooth model were calculated as a result of hot and cold response. The resulting thermo-mechanical stresses were analysed and compared …

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Inherent Differential Propensity Of Dental Pulp Stem Cells Derived From Human Deciduous And Permanent Teeth, Noor Hayaty Abu Kasim Abu Kasim N.H. Aug 2010

Inherent Differential Propensity Of Dental Pulp Stem Cells Derived From Human Deciduous And Permanent Teeth, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

Introduction: Lately, several new stem cell sources and their effective isolation have been reported that claim to have potential for therapeutic applications. However, it is not yet clear which type of stem cell sources are most potent and best for targeted therapy. Lack of understanding of nature of these cells and their lineage-specific propensity might hinder their full potential. Therefore, understanding the gene expression profile that indicates their lineage-specific proclivity is fundamental to the development of successful cell-based therapies. Methods: We compared proliferation rate, gene expression profile, and lineage-specific propensity of stem cells derived from human deciduous (SCD) and permanent …

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Cytotoxicity Of Polyurethane Dimethacrylate Derived From Palm Oil Polyol., Noor Hayaty Abu Kasim Abu Kasim N.H. Jan 2010

Cytotoxicity Of Polyurethane Dimethacrylate Derived From Palm Oil Polyol., Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

Objective: The aim of this study was to investigate the cytotoxicity effect of polyurethane dimethacrylate monomer derived from palm oil polyol (PUDMA) and 2 experimental composite resins based on these monomer PUDMA- based composites) compared to an experimental Bis-GMA/TEGDMA-based composite and EsthetX flowable composite (Dentsply, Caulk, USA). Methods: The experimental composite resins were prepared by mixing 0.25% and 0.75% by weight camphorquinone and ethyl (4-dimethyl amino) benzoate with 60% filler for each of the following monomer systems; I) PUDMA monomer (PUDMA-based composite resin), II) Bis-GMA/TEGDMA at ratio of 75:25 by weight, III) PUDMA/BisGMA-TEGDMA at ratio of 50:50 by weight. Eight …

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Surface Reproduction Of Elastomeric Materials: Viscosity And Groove Shape Effects, Noor Hayaty Abu Kasim Abu Kasim N.H. Jan 2010

Surface Reproduction Of Elastomeric Materials: Viscosity And Groove Shape Effects, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

Objective: To evaluate the effect of viscosity and type of grooves on surface detail reproduction of elastomeric impression materials. Methods: Express putty/light-, Impregum medium- and heavy/light-bodied and Aquasil medium- and putty/light-bodied elastomeric impression materials were chosen for this study. Five impressions were made using a cylindrical aluminum reference block with U- and V- shaped grooves and to produce 35 master dies. Each master die was immersed in distilled water at 370 C for 5 minutes prior to the impression making on moist surfaces. Surface topography of the dies and impressions were captured using Alicona Imaging System. The mean difference in …

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A Finite Element Study Of The Multilayered Structured Dental Post, Noor Hayaty Abu Kasim Abu Kasim N.H. Sep 2009

A Finite Element Study Of The Multilayered Structured Dental Post, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

Ideally, dental post should have stiffness that is similar to the crown at the coronal part and stiffness similar to the dentine at the apical part. This will reduce stress concentration at either coronal or the apical parts of the dentine and minimize the chance of interfacial loosening and enhance the reliability of post. Objective: To investigate the biomechanical behaviour of Multilayered Structured Dental Posts (MSDPs) using finite element analysis (FEA). Methods: Two models of MSDPs consist of multilayer design of xTi-yHA composition added to a zirconia layer (model A) and the same compositions added to alumina layer (model B) …

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The Current Status Of The Case Report: Terminal Or Viable, Noor Hayaty Abu Kasim Abu Kasim N.H. Jan 2009

The Current Status Of The Case Report: Terminal Or Viable, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

The case report, which has a long history in medicine, has seen its fortune wax and wane with time. We discuss the challenges facing the continued survival of the case report, including the inability of journals to cope with the increased load and increased cost of publication, ethical issues, the impact factor and the rise of evidence-based medicine. We highlight the important role that the case report will continue to play in medical research and education, as a means of sharing information and detecting novelty through observations. Most importantly, the case report serves as a stepping stone for young physicians …

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Modification Of Pmma Dental Resin With Palm Oil Based Polyol, Noor Hayaty Abu Kasim Abu Kasim N.H. Jan 2008

Modification Of Pmma Dental Resin With Palm Oil Based Polyol, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

Objectives: This study is an attempt to enhance the properties of conventional PMMA denture material by incorporation of a polyfunctional polyol derived from palm oil by copolymerization with methyl methacrylate monomer to overcome the low fatigue resistance property of PMMA. Methods: A series of copolymerizations of palm oil polyol with MMA was performed in solution. The polyol was added from 40-20 %, MMA from 20-40% , benzoyl peroxide as initiator was at 0.04% and toluene used as solvent was at 60 % of the total weight. The copolymerization was carried out in a 500ml-round-bottom reaction flask, equipped with a magnetic …

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Conversion Of A New Monomer For Dental Resin Application, Noor Hayaty Abu Kasim Abu Kasim N.H. Jan 2008

Conversion Of A New Monomer For Dental Resin Application, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

Objective: The aim of this study was to investigate the degree of conversion and cross-linking of polyurethane dimethacrylate (PUDMA), derived from palm oil polyol, for dental resin application. Methods: Polyurethane dimethacrylate was synthesized by reacting excess amount of Methylene diphenyl diisocyanate (MDI) with palm oil polyol. The resulting isocyanate polyurethane prepolymer was then acrylated using hydroxymethacrylate (HEMA). Fourier transform infrared spectroscopy was used to ascertain the formation of PUDMA, and to determine the degree of conversion (DC) of: I) PUDMA, II) Bis-GMA, III)Bis-EMA,IV) Bis-GMA/TEGDMA (3:1), V) Bis-GMA/TEGDMA(3:1)/Bis-EMA (3:1), VI) PUDMA/Bis-EMA (3:1), VII) Bis-GMA/TEGDMA(3:1)/PUDMA (1:1), and VIII) Bis-GMA/TEGDMA(3:1)/PUDMA/Bis-EMA (1-1-1). The photo …

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Flexural Strength Of Pmma Modified With Palm-Oil Based Polyol, Noor Hayaty Abu Kasim Abu Kasim N.H. Jan 2008

Flexural Strength Of Pmma Modified With Palm-Oil Based Polyol, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

Objectives:Biocompatibility is an important desirable property for a dental polymer and it can be achieved by utilizing more materials from natural sources. The flexural strength of an experimental polymer prepared from MMA monomer modified with palm-oil polyol was compared to two commercial resins,namely the Lucitone 199® (Dentsply Trubyte, USA) and Impact (Ivoclar Vivadent, Liechtenstein). Methods: The experimental polymer was prepared by copolymerizing MMA monomer and palm oil polyol. The resulting polymer was cast into a plate form and sectioned using a precision diamond saw (Buhler, Germany) to form 10 specimens of dimension, 65mm x 11mm x 5mm. These specimens were …

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Demineralization Potential Of Qat Extracts At Composite Restoration Interface, Noor Hayaty Abu Kasim Abu Kasim N.H. Jan 2008

Demineralization Potential Of Qat Extracts At Composite Restoration Interface, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

Objective: To evaluate the demineralization potential of qat extracts at composite restoration interface. Methods: Class V cavities were prepared on the buccal surface of thirty extracted sound premolars and were restored with a nanohybrid composite (Grandio, VOCO, Germany). Specimens were subsequently coated with nail varnish exposing 2mm of enamel around the restoration margin. The specimens were divided into three equal groups of 10 and were then immersed in acid gel and qat extracts (10% and 20%) for 4 weeks. All specimens were removed and washed using deionized water and later examined by direct vision and stereomicroscope prior to sectioning. Specimens …

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Finite Element Analysis Of An Automated Rapid Maxillary Expander (Arme), Noor Hayaty Abu Kasim Abu Kasim N.H. Jan 2008

Finite Element Analysis Of An Automated Rapid Maxillary Expander (Arme), Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

An Automated Rapid Maxillary Expander (ARME), is a specially designed orthodontic appliance to overcome the shortcomings imposed by the traditional butterfly expansion appliance. It operates by automatically widening the maxilla (upper jaw) by expanding the midpalatal suture [1]. This procedure is not feasible after late teenage years due to more rigid facial skeleton features. According to the study by Cozzani [2], the activation of the device could produce 0.25 mm of expansion per day. Over the period of 2 weeks, the expansion produced is up to 7 mm in total [1]. For this study, we explored the mechanism involved in …

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Acquiring Anatomical Representation Of Human Maxilla For Rapid Maxillary Expansion, Noor Hayaty Abu Kasim Abu Kasim N.H. Jan 2008

Acquiring Anatomical Representation Of Human Maxilla For Rapid Maxillary Expansion, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

The purpose of the study is to model and provide a better understanding of maxilla bone involved in the treatment for rapid maxillary expander (RME) for dento-facial applications. The treatment is recommended for patients presented with an arch width deficiency named cross bites. Cross bites often cause abnormal physical forces that disrupt the balance of the occlusal relationship. More commonly, the maxilla or the upper jaw appears to be narrow and contributes to significant degree of crowding in the mouth. Early investigators [1-4] discovered that rapid maxillary expansion resulted in a splitting of the median palatal suture. The expansion is …

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The Effect Of Light Curing Tip Angulations On The Shear Bond Strength Of An Orthodontic Adhesive, Noor Hayaty Abu Kasim Abu Kasim N.H. Jan 2008

The Effect Of Light Curing Tip Angulations On The Shear Bond Strength Of An Orthodontic Adhesive, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

The purpose of this study was to investigate the effect of light curing tip angulations on the shear bond strength of an orthodontic adhesive. Three groups of thirty premolar teeth had brackets attached in a standardized manner using Transbond XT. The orthodontic adhesive were cured with a Blue LED light curing unit for 40 seconds using three different angulations 0 degrees, 45 degrees and 9 degrees at a standardized 3 mm distance. The debonding force was measured using an Instron Universal Testing Machine. Data were computed and analysed using SPSS version 12.0. Kruskal-Wallis test was employed to compare the shear …

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Validation Of Cone Beam Ct Scan For Measurement Of Palatal Depth In Study Casts, Noor Hayaty Abu Kasim Abu Kasim N.H. Jan 2008

Validation Of Cone Beam Ct Scan For Measurement Of Palatal Depth In Study Casts, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

The purpose of this study was to validate the use of digital dental study casts obtained from Cone beam CT Scan (CBCT) against gold standard; that is traditional dental study cast measured with digital caliper. Thirty-four study casts of Malaysian Aborigines were selected from Centre of Malaysian Pribumi Studies Databank. Palatal depth of each study casts were measured using Mitutoyo digital caliper. Subsequently, all the study models were scanned using i-CAT CBCT and the palatal depth were measured using i-CAT software. Data were analysed using SPSS version 12.0 where Intraclass correlation and paired T-test were employed. There was no significant …

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Cutting Efficiency Of Dental Burs-A Pilot Study, Noor Hayaty Abu Kasim Abu Kasim N.H. Dec 2007

Cutting Efficiency Of Dental Burs-A Pilot Study, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

Objectives: This study aim to evaluate the cutting efficiency of tungsten carbide burs (TC) and rotary diamond instruments by measuring their rake angle and visual examination of their cutting surfaces respectively, using scanning electron microscopy (SEM). Materials and Method: 60 short and long head pear-shaped TC and 18 round rotary diamond instruments that had been used to prepare < than 5, > than 5 and > than 10 cavities were selected from the 3rd & 4th year dental students, Dental Faculty, University of Malaya. 12 cylindrical and flame rotary diamond instruments were also selected from the 5th year students. The rake angle of TC was …

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Push-Out Bond Strength Of Luting Agents To Fibre-Reinforced Post: An In Vitro Study, Noor Hayaty Abu Kasim Abu Kasim N.H. Dec 2007

Push-Out Bond Strength Of Luting Agents To Fibre-Reinforced Post: An In Vitro Study, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

The objective of this study was to investigate the effect of various luting agents on bond strength of fibre-reinforced posts to root canal dentine. 40 extracted single rooted sound premolar teeth were root filled, decoronated and randomly divided into four groups. Fibre posts, Aestheti-Plus (TM) (Bisco,Inc. Schaumburg, IL, USA) were cemented using four luting agents: Group A (control): Elite 1000 Zinc phosphate (GC Corp, Japan), Group B: Calibra (TM) Esthetic Resin Cement (Dentsply Caulk, USA), Group C: RelyX ARC Adhesive Resin (3M ESPE), Group D: RelyX Unicem Aplicap (3M ESPE). Each roots were sliced into 2 discs representing the coronal …

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Rolling Ball Contact As A Method For Testing Surface Fatigue Of Resin Based Restorative Materials, Noor Hayaty Abu Kasim Abu Kasim N.H. Jan 2007

Rolling Ball Contact As A Method For Testing Surface Fatigue Of Resin Based Restorative Materials, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

It has been recognised that compressive, tensile and flexural strength do not accurately determine the durability of dental restorations and that fatigue induced failure plays an important role. Fatigue caused by cyclic loading is thought to be responsible for the failure of composites restorations described by chipping, localized or generalized wear and fracture. The main aim of this work is to develop and evaluate the rolling ball contact as a method for testing surface fatigue of resin-based restorative materials. The results showed that material loss during the testing period mimic that of a fatigue failure process occurring in rolling elements. …

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Silverfil: Its Physical Characterization, Noor Hayaty Abu Kasim Abu Kasim N.H. Jan 2007

Silverfil: Its Physical Characterization, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

This article focuses on the physical characterization of Silverfil (R) amalgam. Analysis of the amalgamated material semi-quantitatively showed that Silverfil (R) comprised of approximately two thirds mercury and one third silver. No other elements were detected. Examination of the amalgamated material by x ray mapping and metallographically showed no evidence of free mercury present. Silverfil (R) has strong affinity towards the mercury ion. X-ray Diffraction analysis showed that the amalgamated Silverfil (R) is similar to a mineral in nature called "Moschellandsbergite". The advantages of Silverfil (R) over conventional amalgam were highlighted.

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Fabrication Of 316l Stainless Steel Parts By Injection Moulding For Biomedical Application Using A Novel Binder, Noor Hayaty Abu Kasim Abu Kasim N.H. Jan 2007

Fabrication Of 316l Stainless Steel Parts By Injection Moulding For Biomedical Application Using A Novel Binder, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

This paper focuses on the usage of a novel binder system base on palm oil product to produce sintered parts of stainless steel 316L produced by vertical injection molding technique for biomedical application. The stainless steel 316L powder was mixed using z-blade mixer with the thermoplastic binder system comprising of polyethylene, paraffin wax, stearic acid and palm stearin which was derived from palm oil at different volume percent (%). The feedstock then was studied in term of viscosity and shear rate using capillary rheometer. The feedstock was molded using vertical injection molding machine. After molding, the green molded part was …

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Standardization Of Distance And Angulation Of Light Curing Unit Tip Using Distometer, Noor Hayaty Abu Kasim Abu Kasim N.H. Jan 2007

Standardization Of Distance And Angulation Of Light Curing Unit Tip Using Distometer, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

The purpose of this study was to investigate the light intensity of selected light curing unit with varying distance and angulation of the light curing tip and lightmeter. Four types of light units; Spectrum 800 (Dentsply), Coltulux 3 (Coltene), Elipar FreeLight 2 (3M Espe) and Starlight Pro (Mectron) were evaluated for light intensity at various distance between the light curing tip and the lightometer Cure Rite Denstply (0, 1, 3, 5, 10 and 15 mm). The light curing units were angulated at 45 degrees, 60 degrees and 90 degrees at a standardized 5 mm distance. The intensity of light curing …

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Effect Of Mouthrinses On Surface Microhardness Of Selected Dental Composites, Noor Hayaty Abu Kasim Abu Kasim N.H. Jan 2006

Effect Of Mouthrinses On Surface Microhardness Of Selected Dental Composites, Noor Hayaty Abu Kasim Abu Kasim N.H.

Noor Hayaty Abu Kasim Abu Kasim N.H.

Objective: To compare the surface microhardness of composites(Spectrum®TPH, Filtek™Z350, Ceram•X mono and Ceram•X duo-enamel shade) before and after immersion in alcohol containing mouthrinses (Listerine), alcohol-free mouthrinses (Oral-B) and experimental herbal mouthrinses based on plant extract (mouthrinses X, Y and Z). Methods: 60 disc-shaped specimens of approximately 10mm x 2mm were perpared from various composites using perspex split mould and was cured for 40 seconds. The irradiated surface was polished using Sof-Lex pop-on polishing discs. The specimens were randomly divided to 6 groups. Microhardness was recorded before immersion (control group) using a load of 200g for 15 seconds using Vickers microhardness …

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