Medicine and Health Sciences Commons^™

Perspectives For Titanium-Derived Fillers Usage On Denture Base Composite Construction, Nidal Elshereksi

Nidal Elshereksi

Poly(methyl methacrylate) (PMMA) is an extensively used material in dentistry because of its aesthetics, processability, and reparability. However, PMMA is still far from being ideal in fulfilling the mechanical requirements of prosthesis. PMMA-based denture base polymers exhibit low fracture resistance and radiopacity behavior. Efforts to improve the mechanical and radiopacity properties of denture base materials through inclusion of silica-based fillers are ongoing. Although silane-treated siliceous fillers are commonly used, they are not sufficiently strong.They also exhibit cracks, which either cut through the glass fillers or propagate around the filler particles. This defect occurs when the dental composites are placed in …

Endodontic Repair Filling Materials: A Review Article., Ahmed A. Madfa

Ahmed A. Madfa

The emergence of Mineral Trioxide Aggregate (MTA) as endodontic repair filling material has generated a lot of interest due to its superior sealing ability and biocompatibility. Although MTA possesses superior sealing ability to traditional endodontic repair filling materials, such as calcium hydroxide, but it has poor handling characteristics. A novel endodontic repair filling materials with similar chemical composition, but improved handling characteristics, was recently developed. Recently, BioAggregate repair filling materials is claimed as biocompatible material and promotes cementogenesis and forms a hermetic seal inside the root canal. More recently, Biodentine and EndoSequence endodontic repair materials introduced to the market. Both …

Thermal Characterisation Of Poly(Methyl Methacrylate) Filled With Barium Titanate As Denture Base Material, Nidal Elshereksi

Nidal Elshereksi

No abstract provided.

Advantage Of Combined Amalgam-Composite Restoration: In Vitro Leakage Study, Ahmed A. Madfa

Ahmed A. Madfa

Purpose: Evalute the leakage of Class II box composite restorations and compared with composite lined by flowable composite and combined amalgam-composite restoration. Method: Fifty-four Class II box shaped cavities were on the distal (1 mm below CEJ) surfaces, 18 cavities for each. Scotchbond Multi-Purpose adhesive system, Filtek Z250 composite, and a metal band system were used for all. After thermocycling test (1000 cycles, 5–55°C with 30 s) and dye immersion, the teeth were sectioned longitudinally in a mesio-distal direction and dye penetration was recorded. Results: Combine amalgam-composite restorations showed less gingival leakage than composite alone and composite lined by flowable …

Application Of Calcium Phosphate Materials In Dentistry, Ahmed A. Madfa

Ahmed A. Madfa

Calcium phosphate materials are similar to bone in composition and in having bioactive and osteoconductive properties. Calcium phosphate materials in different forms, as cements, composites, and coatings, are used in many medical and dental applications. This paper reviews the applications of these materials in dentistry. It presents a brief history, dental applications, and methods for improving their mechanical properties. Notable research is highlighted regarding (1) application of calcium phosphate into various fields in dentistry; (2) improving mechanical properties of calcium phosphate; (3) biomimetic process and functionally graded materials. This paper deals with most common types of the calcium phosphate materials …

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 …

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 …

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 …

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.

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 …

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 …

Fracture Resistance Of Endodontically Teeth Restored With Functionally Graded Posts, Ahmed A. Madfa

Ahmed A. Madfa

Objectives: To evaluate the fracture resistance and failure mode of endodontically teeth restored with functionally graded structured (FGS) posts compared to titanium and cast posts. Methods: Single canals in 70 bovine incisors were instrumented, irrigated, obturated and divided into seven groups. They were then root restored with titanium, cast and 3 experimental FGS posts of different compositions; ZrO2-Ti-HA, Al2O3-Ti-HA and Ti-HA. Two control groups were also included; sound teeth and those root treated only. All posts were cemented with zinc phosphate cement and built up with composite core. Crowns margins of 1 mm chamfer finishing line were prepared to receive …

3d-Fe Analysis Of Functionally Graded Structured Dental Posts, Ahmed A. Madfa

Ahmed A. Madfa

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 …

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 …

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 …

Hydroxyl-Terminated Poly(Urethane Acrylate) As A Soft Liner In Dental Applications: Synthesis And Characterization, Selda Keskin

ABSTRACT: Hydroxyl-terminated poly(urethane acrylate) s were synthesized for use in biomedical applications. Acrylate end capping via an interesterification reaction was successfully achieved with methacryloyl chloride addition to the hydroxyl ends of the polyurethane at low temperatures. 2,4-Toluene diisocyanate, 1,6-hexane diisocyanate, and methylene diphenyl diisocyanate were used as diisocyanates for urethane synthesis, and they were end-capped with methyl methacrylate and hydroxyethyl methacrylate. The nature of the monomers that we used had an effect on the thermal and morphological properties that were interpreted in terms of the level of hydrogen bonding and the degree of phase separation. The synthesized polymers were characterized …

Microtensile Bond Strength Of Self-Adhesive Resin-Based Dental Cement, Selda Keskin

This study investigated the effectiveness of bleaching agents on the micro tensile bond strength (mTBS) of self-adhesive luting cement and enamel. A total of 126 samples were prepared from the labial surfaces of permanent human maxillary central incisors and assigned into three groups with 42 samples each as: control, enamel bleached with 10% hydrogen peroxide (HP), and enamel bleached with 10% carbamide peroxide (CP). Rely X Unicem1 (3 M, ESPE) was used as self-adhesive resin cement. The total testing period for bleaching was selected as 14 days and the bleaching agents were applied 8 hours a day. The statistical one-way …

Effect Of Au And Au@Ag Core-Shell Nanoparticles On The Sers Of Bridging Organic Molecules., Remziye Guzel Dr., Zafer Ustundag Dr., Haslet Eksi, Selda Keskin Dr., Bilge Taner, Zeynep Durgun, Ali Osman Solak Prof. Dr.

No abstract provided.

New Generation Of The Dental Posts For Endodontic Application., Ahmed A. Madfa

Ahmed A. Madfa

Fabricated multilayer dental post with the functionally graded design is a novel product that exhibits graded properties varied from coronal to apical parts of the tooth. The new dental post definitely performs better than posts available in the market and improves the quality of human life

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 …

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 …

Effects Of Different Denture Cleansers On The Tensile Bond Strength Of Denture Liners, Selda Keskin

The effect of two denture cleansers (Polident1 and Protefix1) on the tensile bond strength between four soft liner materials (Molloplast B1, Permaflex1, Sofreliner Tough Medium1, and GC Reline Soft1) and a conventional denture base resin was investigated. For each of the liner materials 35 test specimens were prepared according to test the requirements and assigned into seven groups (n¼5). Before tensile testing, five of the liner specimens were kept in water or soaked in two cleansing solutions during 2 and 7 d. Five other samples served as a control group subjected directly to tensile testing. The bond strength values were …

Tensile Bond Strength Of A Highly Cross-Linked Denture Tooth To The, Selda Keskin

This study compared tensile bond strengths between conventional compressionmolded heat (HC)-, auto (AP)-, and microwave-polymerized (MC) poly(methyl methacrylate)-based denture resins and a relatively new injection-molded, microwave-polymerized polyurethane based resin (MI) bonded to a highly cross-linked denture tooth. In the first part of the experiments, denture teeth were used as received. In the second part, they were treated with dichloromethane to see its effect on bonding of conventional denture bases (HCS and APS). Bond strength was tested in tension according to ADA specification No.15. The results showed that the HC group failed cohesively because of higher interface bonding (49.95 MPa) compared …

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) …

A Finite Element Study Of The Multilayered Structured Dental Post, Ahmed A. Madfa

Ahmed A. Madfa

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) …

Effect Of Filler Incorporation On The Fracture Toughness Properties Of Denture Base Poly(Methyl Methacrylate), Nidal Elshereksi

Nidal Elshereksi

Poly(methyl methacrylate) (PMMA) is the material of choice for denture base construction. In spite of its many good qualities, the application of PMMA as an ideal dental base material is still restricted by a few limitations. One of these is the difficulty in achieving intrinsic radiopacity in the material. The aim of the present study is to investigate the possibility of using barium titanate (BaTiO3) as a radiopacifier in PMMA. The formulation used in this study composed of PMMA 89.5 wt%, BaTiO3 10 wt% and benzoyl peroxide (BPO) 0.5 wt% as an initiator, methyl methacrylate (MMA) 90 wt% as a …

Effect Of Filler Incorporation On The Fracture Toughness Properties Of Denture Base Poly(Methyl Methacrylate), Nidal Elshereksi

Nidal Elshereksi

Poly(methyl methacrylate) (PMMA) is the material of choice for denture base construction. In spite of its many good qualities, the application of PMMA as an ideal dental base material is still restricted by a few limitations. One of these is the difficulty in achieving intrinsic radiopacity in the material. The aim of the present study is to investigate the possibility of using barium titanate (BaTiO3) as a radiopacifier in PMMA. The formulation used in this study composed of PMMA 89.5 wt%, BaTiO3 10 wt% and benzoyl peroxide (BPO) 0.5 wt% as an initiator, methyl methacrylate (MMA) 90 wt% as a …

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 …

Synthesis And Characterization Of Poly(Allyl Methacrylate) Obtained By Free Radical Initiator., Selda Keskin

Allyl methacrylate was polymerized in CCl4 solution by a,a0-azoisobutyronitrile at 50, 60, and 708C. The kinetic curves were autoaccelarated types at 60 and 708C, but almost linear at 508C. Arrhenius activation energy was 77.5 kJ/mol. The polymer was insoluble in common organic solvents. It was characterized by FT-IR, NMR, DSC, TGA and XPS methods. About 98–99% of allyl side groups were remained as pendant even after completion of the polymerization. The spectroscopic and thermal results showed that polymerization is not a cyclopolymerization type, but may have end group cyclization. The high molecular weight is the main cause of a polymer …

The Evaluation Of Some Flexural Properties Of Denture Base Resin Reinforced With Various Aesthetic Fibers, Selda Keskin

No abstract provided.