Dentistry Commons^™

Comparison Of Mechanical And Optical Properties Between Three Different Cad/Cam Materials, Aasem Mutlaq Alhenaki

Student Theses, Dissertations and Capstones

Objective. This study aims to compare several mechanical and optical properties between three different CAD/CAM materials. The properties tested are: flexural strength, modulus of elasticity, hardness, translucency and surface gloss. Background. Typically, CAD/CAM restorations are either ceramic based or resin based. A new resin-ceramic hybrid material has recently been introduced and is thought to combine the advantages of both materials. Methods. Samples were divided into three groups, leucite-reinforced porcelain (IPS Empress CAD), lithium dicilicate (IPS e.max CAD) and resin-ceramic hybrid material (Vita Enamic). Twenty-six bar-shaped specimens were fabricated for each group by cutting standard CAD/CAM blocks. 3-point bending test and …

Effect Of Surface Preparation On The Shear Bond Strength Of Orthodontic Brackets Bonded To Zirconia : An In-Vitro Study, Nathaniel Wieder

Student Theses, Dissertations and Capstones

Objectives: The purpose of this in-vitro study was to evaluate the effects of three different surface preparation methods on the shear bond strength of orthodontic brackets bonded to zirconia and determine the most appropriate method. Methods: 45 zirconia and 30 leucite-reinforced porcelain mandibular premolar crowns were divided into 5 groups and received the following surface preparations: 37% phosphoric acid and non-hydrolyzed silane, 4% hydrofluoric acid and hydrolyzed silane, microetch with 50μ Al ₂ O₃ particles. A universal adhesive primer containing MDP was applied and the brackets were bonded with a bis-GMA composite resin. Shear bond strength (SBS) at bond …

Comparison Of The Effectiveness Of Mechanical And Chemical Procedures To Decontaminate Titanium Disks And To Promote Osteoblast Attachment, Flavia Goncalves

Student Theses, Dissertations and Capstones

Objective: This study was conducted to determine the effectiveness of physical and mechanical disinfection of P. gingivalis from implant disks and to evaluate bone cells growth and attachment to the disks. Background. Each year, over three million of Americans replacing missing teeth with dental implants. An inflammatory process around an implant that causes bone loss, characterizes peri-implantitis, first diagnosed in the 1980s. The prevalence is approximately 22%. To date, no treatment protocol of peri-implantitis has been proposed. Methods. 207 implants disks. Four different implant surfaces utilized. Disks were contaminated by p. gingivalis and consequentially disinfected by physical means (spraying prophy …

In Vitro Comparison Of Force Decay Between Three Orthodontic Sliding Retraction Methods, Pamela Steiger

Student Theses, Dissertations and Capstones

Objective: The purpose of this in vitro study was to determine if there is a difference in force decay between three sliding retraction methods under a standardized force delivery system (200 gm at 25 mm stretch) at 2, 4, 6, and 8 weeks. Background: In order to achieve proper esthetics, occlusion and stability, orthodontic treatment may require extractions. Elastomeric chains, Nickel Titanium (NiTi) coils, and active ligatures are commonly used to close these extraction spaces. Methods: Twenty samples of each retraction method (elastomeric chains, NiTi Coils and active ligatures) were evaluated under standardized conditions (200 gm at 25 mm). The …

Cephalometric Regional Superimpositions -- Digital Vs. Analog Accuracy And Precision : 3. The Cranial Base, Douglas Shaw

Student Theses, Dissertations and Capstones

Objective. To assess the accuracy and precision in measurement of pairwise implant displacement across three methods of cranial base superimposition. Background. Cephalometric superimposition is the principal radiographic method used to evaluate changes within the craniofacial skeleton. Many studies have examined the accuracy of software intended to produce cephalometric superimposition. Such studies have utilized anatomic landmarks, selected by the respective software manufacturers, as registration points for constructing superimpositions and their analysis. As a result, these studies are only as accurate as the stability and validity of anatomic registration landmarks used. To our knowledge, no other study has utilized metallic implants to …

Effect Of Cad/Cam Processing On Esthetic Characteristics Of Porcelain Veneers, Eduardo Cortes-Contreras

Student Theses, Dissertations and Capstones

Introduction: Dentistry has changed significantly during the last two decades. Patients are more aware and demanding of the latest technologies available in restorative dentistry. The purpose of this study was to determine any possible changes on the surface roughness, gloss and color change of CAD-CAM milled porcelain veneers following repeated milling times, before and after a glazing process. Methods: A Teflon disk-shaped mold was used as a cast to take a digital impression (BlueCam) in order to fabricate cylindrical-shaped specimens. A total of one hundred (N=100) specimens porcelain veneers using Empress CAD (I10) block, were milled using the CAD/CAM CEREC-SIRONA …

Evaluation Of The Effect Of Enamel Deproteinization On Shear Bond Strength Of Orthodontic Adhesives And Resulting White Spot Lesion Formation, Kelly Chioffe

Student Theses, Dissertations and Capstones

A thesis submitted to the College of Dental Medicine of Nova Southeastern University of the degree of Master of Science in Dentistry.

Objective: The objectives of this study were 1) to evaluate the effect of enamel deproteinization on the shear bond strength(SBS) of orthodontic brackets bonded with a resin modified glass-ionomer (RMGI) adhesive and a composite resin, 2) to determine the mode of bond failure according to the adhesive remnant index (ARI) and 3) to evaluate the effect of these adhesives in the prevention of white spot lesions (WSLs). Background: WSLs are a concern for orthodontic patients. RMGI orthodontic adhesives …

Bmp2 Induced Osteogenic Differentiation Of Human Umbilical Cord Stem Cells In A Peptide-Based Hydrogel Scaffold, Shruthi Lakshmana

Student Theses, Dissertations and Capstones

Craniofacial tissue loss due to traumatic injuries and congenital defects is a major clinical problem around the world. Cleft palate is the second most common congenital malformation in the United States occurring with an incidence of 1 in 700. Some of the problems associated with this defect are feeding difficulties, speech abnormalities and dentofacial anomalies. Current treatment protocol offers repeated surgeries with extended healing time. Our long-term goal is to regenerate bone in the palatal region using tissue-engineering approaches. Bone tissue engineering utilizes osteogenic cells, osteoconductive scaffolds and osteoinductive signals. Mesenchymal stem cells derived from human umbilical cord (HUMSCs) are …

Influence Of Immediate Dentin Sealing On The Bond Strength Of Indirect Bonded Restorations, Alexander Duque

Student Theses, Dissertations and Capstones

Introduction: A critical issue and concern that has been documented in dentistry is the complexity of bonding to dentin, a fact that has been referred to as a less reliable technique due to the intrinsic characteristics of the dentin substrate. Effectiveness on dentin bonding is a clinical important approach for indirect bonded restorations in order to achieve a good adhesion that can surpass the test of time. Long-term clinical trials have shown that indirect bonded restorations have an increased risk of failure when using dentin as the major substrate. Consequently, an effort should be made to improve techniques and materials …

Cephalometric Regional Superimpositions -- Digital Vs. Analog Accuracy And Precision : 1. The Maxilla, Glenn Krieger

Student Theses, Dissertations and Capstones

Introduction: The purpose of this study was to measure the displacement of defined dental structures, as a result of superimposition of cephalometric images across paired time-points by both digital and analog methods. The magnitudes of such displacements across three methods of superimposition were compared to each other and to a reference method constructed by registering superimposed cephalometric images on tantalum markers implanted in the study participants' maxillae. The defined dental structures were: 1) First molar mesial contact point; 2) First molar apical root bisection; 3) Central incisor root apex; 4) Central incisor crown incisal edge. Methods: Lateral cephalograms of 22 …

Effect Of Resin Cement, Aging Process And Root Level On The Bond Strength Of The Resin-Fiber Posts, Khalid Almulhim

Student Theses, Dissertations and Capstones

Background . Little is known about the long-term clinical bonding effectiveness of the Fiber-reinforced composite (FRC) posts cemented with self-etch adhesive systems. Bond stability and longevity of the cemented post are adversely affected by physical and chemical factors over time, such as expansion and contraction stresses caused by thermal changes and occlusal load. This clinical condition can be simulated in vitro by thermocyclic loading; and bonding effectiveness can be evaluated by applying the micropush out test. Therefore, more in vitro studies are needed to evaluate the bond strength of the fiber posts cemented with different resin cement systems after simulating …

Fluoride Release, Recharge, And Re-Release From Four Orthodontic Bonding Systems, Amy Bouvier

Student Theses, Dissertations and Capstones

A thesis submitted to the College of Dental Medicine of Nova Southeastern University of the degree of Master of Science in Dentistry.

Objectives: To determine the amount of initial fluoride release from four orthodontic bonding systems over a period of four weeks, and then to subject these materials to an external source of fluoride for recharge in order to measure the amount of fluoride re-release over another four-week interval. Additionally the surface morphology of these materials was analyzed under the scanning electron microscope in order to identify microscopic changes in the materials that may have occurred during the experiment. Methods: …

Effects Of Synthetic Cortical Bone Thickness And Force Vector Application On Temporary Anchorage Device Pull-Out Strength As Related To Clinical Perspectives Of Practicing Orthodontists, Ira Rothstein

Student Theses, Dissertations and Capstones

December 2011.

A thesis submitted to the College of Dental Medicine of Nova Southeastern University of the degree of Master of Science in Dentistry.

Background: Temporary anchorage devices (TADs) provide a versatile means by which orthodontic anchorage can be established without the need for patient compliance and complex force systems. Their use is predicated on their ability to remain stable throughout the course of treatment in which they are needed. This has been shown to be the result of "primary stability" which is achieved through mechanical interlocking of the screw threads with the surrounding bone immediately upon placement. Therefore, evaluating …