Dentistry Commons^™

Bacterial Adherence Of Streptococcus Mutans And Lactobacillus Acidophilus On Poly-Methyl Methacrylate And Thermoplastic Polypropene Used In Orthodontic Retention, Lindsay Ann Pfepper

UNLV Theses, Dissertations, Professional Papers, and Capstones

Retention is required in the majority of orthodontic patients throughout the remainder of their life. The two primary removable appliances are known as the traditional Hawley retainer or the vacuum formed retainer. These appliances were developed to maintain the position of the dentition without sacrificing oral health. The orthodontic population is at a higher risk for caries due to plaque accumulation from poor diet, suboptimal oral hygiene and often lack of motivation. These two retainers occupy different niches and are comprised of different materials; therefore the retainers' effect on oral health could be very different. An understanding of which bacteria …

Practicing Orthodontists' Use And Perceived Efficacy Of Self-Ligating Brackets, John-David Beuhler

UNLV Theses, Dissertations, Professional Papers, and Capstones

Introduction.

The purpose of this study was to compare perceptions of efficacy and efficiency of Self-Ligating Brackets vs. conventional brackets between practicing Orthodontists and Orthodontic Residents.

Methods.

Cross-sectional survey research using a three-wave emailing of addresses from the current American Association of Orthodontists directory. The directors of all orthodontic residency programs in the US were asked to also distribute to all residents. The survey included five sections: (1) respondents' experience, (2) factors that influence, (3) positive or negative factors, (4) the perceived efficiency/efficacy, and (5) demographics. A 39% response rate (N=707) was obtained.

Results.

Over half (51.8%) …

Effect Of Toothbrush Abrasion On Frictional Resistance Of Aesthetic Orthodontic Archwires, Stephen Alexander Yamodis

UNLV Theses, Dissertations, Professional Papers, and Capstones

Fixed orthodontic appliances (braces) are one of the most widely used appliances to correct malocclusion, however many patients prefer less metal display. To meet this demand more esthetically pleasing brackets and archwires have been developed. These esthetic components are often clear, white or tooth colored. Coatings of various types are commonly used to produce an esthetic archwire. However, these coating materials tend to wear and degrade, which may cause binding and increased resistance to friction, thereby potentially reducing the efficiency of tooth movement. Therefore, in vitro testing of tooth brush abrasion on frictional resistance of various aesthetic archwires was tested. …

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 …

In Vivo Measurement Of Color Relationships Between The Maxillary Central Incisor And Canine As A Function Of Age, Marie E. Falcone

Master's Theses

Abstract

Introduction

It has long been taught that the basic shade (hue) of the patient can be taken from the canine (i.e. that tooth thought to have the highest chroma of a particular hue) and then that hue can be applied to other anterior teeth but at a lower chroma. However, this concept does not appear to derive from published measurements or observations. This study documented the color relationship between in vivo maxillary central incisors and canines to examine: (1) whether they share the same hue, but have different chromas (as commonly taught); and, (2) whether color differences (∆E values) …

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 …

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 …

Frictional Resistance Of Aesthetic Orthodontic Arch Wires Compared To Traditional Arch Wires Before And After Toothbrush Abrasion, Stephen Yamodis, Jeremy Manuele, Adam Kessler, Brendan O'Toole, James Mah, Bob Martin

Festival of Communities: UG Symposium (Posters)

Our objective was to compare frictional resistance evident in aesthetic archwires to traditional (non-aesthetic) archwires. Methods: Archwires ligated with elasatics to fixed brackets were pulled through these brackets while frictional resistance (in lbf) was measured. Results: There were no confirmed significant differences between the frictional resistance of the aesthetic arch wires compared to the traditional non-coated wires for all wire sizes tested Conclusions: Our data suggests that a sacrifice of clinical performance with these aesthetic archwires as compared to traditional archwires is not likely

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 …

The Evolution Of Prophy Paste, Caren M. Barnes

College of Dentistry: Faculty Publications

Dental hygienists have many products to choose from when deciding which prophy paste is best for each patient. To date, the evidence supporting prophy pastes formulated to remineralize enamel or eliminate dentinal hypersensitivity is somewhat unclear. Most of the research has been conducted in vitro among environments that do not accurately simulate clinical conditions. Additional clinical research performed in vivo is needed to provide the evidence base necessary for effective clinical decision making.

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 …

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 …