Dental Materials Commons^™

Accuracy Of Digital Impressions At Varying Implant Depths: An In-Vitro Study, Vivia Sequeira

Graduate Theses, Dissertations, and Problem Reports

Introduction: Implants placed at variable depths may vary the amount of visible scannable surface of a scan body. Intraoral scanner technology uses advanced optical principles to record the surface of the scan body to accurately capture the implant position.

Purpose: To investigate the effect implant placement depth has on the accuracy of digital implant impressions using an intraoral scanner.

Materials & Methods: A partially edentulous gypsum master model was fabricated to allow the positioning of a single implant analog at different depths. Four groups based on the planned implant depths of 0, 3, 6 and 7mm and corresponding visibility of …

Effect Of Nanofiller Coating And Loading On Facial Elastomer Physical Properties, Rahmi K. Aulia

Theses & Dissertations

Current materials used for facial prostheses are far from being desirable, and improved properties with “skin-like” feel are needed. This study evaluates property changes induced by sequential additions of uncoated and hydrophobic-coated nano-SiO₂ to polydimethylsiloxane (PDMS) and compares them with those measured for conventional submicron SiO₂-filled materials. Each filler type was sequentially added to vinyl-terminated PDMS at 0%, 0.5%, 5%, 10%, and 15% by weight. Tensile, tear, Durometer hardness, translucency and viscoelastic properties were evaluated, with hardness and translucency also evaluated following 3000 hours of outdoor weathering. Results demonstrated that 15% coated nano-SiO₂-filled PDMS materials …

Metal Additive Manufacturing For Fixed Dental Prostheses, Mai El Najjar

Electronic Thesis and Dissertation Repository

The use of additive manufacturing (AM) in dentistry has gained momentum in recent years. However, high initial costs and uncertainty surrounding the quality of AM products are considered barriers to their use. This research compared dental substructures fabricated by AM versus conventional casting and milling.

Cobalt-chromium alloy rectangular bars and three-unit bridge substructures were fabricated by AM, casting or milling. Bars manufactured by AM exhibited superior flexural strength, shear bond strength of porcelain coating, and Vickers hardness. Bridge substructures fabricated by AM showed similar flexural stiffness to cast, similar flexural loads at failure to milled and cast, and overall accuracy …

Exploring The Use Of Pulsed Erbium Lasers To Retrieve A Zirconia Crown From A Zirconia Implant Abutment, Ahmed Elkharashi

Theses and Dissertations

Removal of zirconia crowns, commonly used as cement-retained implant fixed restorations, can be challenging. Conventional methods of crown removal are time consuming and often leave irreparable damage to the crown, which can be costly to patients and practitioners. This research explored the use of two different types of pulsed erbium lasers, erbium-doped yttrium aluminum garnet laser (Er:YAG) and erbium, chromium-doped yttrium, scandium, gallium and garnet (Er,Cr:YSGG), as non-invasive tools to retrieve cemented zirconia crowns from zirconia implant abutments. Times needed to remove the crowns were recorded and analyzed using ANOVA (��=0.05). No statistical differences between the debond times of each …

The Visual And Spectrophotometric Effect Of External Bleaching On Omnichroma Resin Composite And Natural Teeth, Michael Brian Evans

Graduate Theses, Dissertations, and Problem Reports

Objective: To determine the visual and spectrophotometric effect external tooth bleaching has on natural tooth structure and OMNiCHROMA composite at various number of treatments. Variables were compared to determine if there is a detectable difference between the composite and the tooth before and after bleaching.

Methods: Preparation and restoration of 25 previously extracted teeth was completed. OMNiCHROMA composite was used. Each tooth was measured visually with a VITA shade guide and a colorimeter. Measurements were recorded before bleaching, after 5 and 10 treatments. Statistical analysis was completed and ΔE values between the composite and tooth were compared between the 3 …

Evaluation Of Die Trim Morphology Made By Cad/Cam Technology, Pratiksha Agrawal

Master's Theses (2009 -)

Purpose: The purpose of this vitro study was to evaluate the accuracy of the morphology of digitally trimmed dies in comparison with the subgingival contour of a prepared tooth to be restored with a single crown. Materials and Methods: 20 human extracted teeth, 10 incisors and 10 molars were disinfected, mounted on dentoforms. The teeth were prepared for a single all ceramic restoration. Digital impressions of the preparations were made using the 3M Lava COS. With the data, the SLA models were fabricated with removable dies. The prepared tooth and the corresponding dies were then compared with the Rhino software. …

Effects Of Microwave Irradiation On The Dimensional Stability Of Complete Denture Bases, Miguel Pappaterra

Loma Linda University Electronic Theses, Dissertations & Projects

Introduction: Maintenance for complete dentures is a role that must be undertaken by the patient. It has been determined that two minutes of microwave irradiation at 650 Watts provides denture disinfection, and three minutes provide sterilization32,34. There is insufficient data on how this practice affects the long term dimensional stability of commonly used complete denture bases in the United States. Purpose: The purpose of this study was to perform an in-vitro investigation, testing and comparing the effects of microwave irradiation on the dimensional stability of three types of complete denture bases. Materials and Methods: An edentulous master cast with reference …

Virtual Three-Dimensional Analysis Of Dimensional Accuracy Of Dental Master Die Models Created By The Iterotm Electronic Impression Device And Those Made From A Polyvinyl Siloxane Impression Material, Polina P. Shcherbatov

Master's Theses

No abstract provided.

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) …

The Effect Of Auxiliary Preparation Elements On The Resistance Form Of Complete Metal Crowns, Mostafa Nazari

Loma Linda University Electronic Theses, Dissertations & Projects

This study measured the resistance to dislodgment of complete metal crowns when they were fabricated for tooth preparations lacking resistance form. These preparations were modified with four different auxiliary preparation features.

An Ivorine mandibular first molar was prepared on a milling machine with the following characteristics: 20 degrees of total occlusal convergence (TOC), 360 degrees shoulder finish line of 1.0 mm width, and axial wall of reduced height offering no geometric resistance form. The following tooth preparation modifications were studied:

1. Two proximal grooves (two lingually positioned grooves, one on the mesial and one on the distal surface) (design B) (Figures …

Effect Of Auxiliary Preparation Elements On Resistance Form Of Complete Crowns, Manuel H. Guevara

Loma Linda University Electronic Theses, Dissertations & Projects

This study compared the effectiveness of six different auxiliary preparation elements on the resistance to lateral dislodgment of complete crown preparation lacking resistance form.

An ivorine mandibular first molar was prepared with the following characteristics: 20° TOC, 360° shoulder finish line of 1.0 mm width and axial wall of reduced height offering no geometric resistance form (Group A: control). Preparation modifications were Group B: MD grooves, Group C: BL groves (sic), Group D: MDBL grooves, Group E: MD small boxes, Group F: MD large boxes and Group G: 8° TOC at the cervical 2 mm of the axial walls. Ten …

Immediate Loading Of Unsplinted Implants In The Anterior Mandible For Overdentures, Phillip Roe

Loma Linda University Electronic Theses, Dissertations & Projects

In this one-year prospective study, eight completely edentulous patients were selected from the Loma Linda University School of Dentistry (LLUSD) patient population to participate. There were five male and three female patients, between the ages of 58 and 82 (mean age of 69.1 years). All participants received new maxillary and mandibular complete dentures prior to implant placement. Two 4.0 mm x 13 mm threaded implants with a fluoride-modified, micro-roughened, titanium surface were placed mesial to each mandibular canine position. Locator abutments were connected and torqued to 25 Ncm and primary closure was achieved with a nonresorbable suture material. The Locator …

Short-Term Clinical Evaluation Of Nobelreplace® Tapered Groovy Implant, Manouchehr Pouresmail

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this clinical investigation was to make comparisons and to achieve estimates of the short-term implant success, marginal bone resorption, and soft tissue responses around the immediately loaded NobelReplace® Tapered groovy implant (with groove on a rough collar portion) as compared to an implant without a groove on the collar (Replace®Select Tapered). This was a randomized controlled and prospective investigation in which subjects were consecutively included according to strict inclusion/exclusion criteria. Single stage procedure was used with immediate function. Seventeen subjects were recruited, and were randomly divided in two groups. Each group was received the predetermined type of …

An In-Vitro Investigation Of The Physical Properties Of Alginate Alternatives, Rishi Dinesh Patel

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to evaluate the detail reproduction, gypsum compatibility and linear dimensional change of three recently introduced irreversible hydrocolloid (alginate) alternatives. The materials that were tested are Position Penta Quick® (3M ESPE™), Silgimix® (Sultan Dental) and Alginot® (Kerr™). These materials were tested in accordance with ANSI/ADA Specification No. 18 for Alginate Impression Materials and No. 19 for Dental Elastomeric Impression materials. The irreversible hydrocolloid impression material Jeltrate Plus antimicrobial® (Dentsply Caulk™) served as the control.

MATERIALS AND METHODS: The ADA specification die was used to undertake the testing of the new materials. The parameters of detail …

Immediate Provionalization Of Single Threaded Oxidized Implants On Maxillary Premolars Healed Sites: One-Year Study, Kiyotaka Umezu

Loma Linda University Electronic Theses, Dissertations & Projects

Osseointegrated endosseous implants have been widely used and become a predictable treatment option for completely and partially edentulous patients. The viability and predictability of this treatment modality have been supported with the high success rates in numerous studies. Clinical guideline requires a healing period of 3 to 6 months without functional loading to achieve osseointegration with machine surface implants. Therefore, numerous studies on immediately loaded implants have been conducted in an attempt to minimize or eliminate this healing period. The purpose of this study was to evaluate the success rate of the immediately provisionalized oxidized-surface implants in healed sites supporting …

Immediate Provisionalization Of Single 3.0 Mm Diameter Implant In Maxillary And Mandibular Anterior Region, Kotaro Oyama

Loma Linda University Electronic Theses, Dissertations & Projects

Immediate provisionalization of single implants with standard (3.75 - 4.5 mm) and wide diameter (> 4.5 mm) has been well documented. When the space is limited, small diameter implants (3.0 mm) must be used. Although high success rates have been reported, they were limited to healed site and were placed as staged procedures. The purpose of this prospective study was to evaluate the success rate and peri-implant tissue response of small diameter (3.0 mm) implants undergoing immediate provisionalization in the esthetic area.

Eleven patients who had missing maxillary lateral incisor(s) and/or mandibular incisor(s) participated in this study. Thirteen 3.0 mm …

Effect Of Gutta Percha On The Retention Of A Post Using Different Cements, Saeda H. Basta

Loma Linda University Electronic Theses, Dissertations & Projects

This study evaluated the effect of residual gutta percha on the retention strength of prefabricated post cemented with four different cements. Forty intact mandibular single canal canines or premolars were selected for standardized size and quality, endodontically treated, and decoronated to the cementoenamel junction. A post space was prepared to accommodate Para post XP size 4 (Coltene, Whaledent Inc., Cuy Falls, Ohio) to a depth of 8 mm. The Obtura heated gutta percha system was used to inject a very thin line of gutta percha along one lateral wall to the depth of the future post. Forty obturated teeth were …

Evaluation Of Three Bonding Agents In The Repair Of Fractured Veneered Stainless Steel Crowns, Jennifer Liane Hoffer

Loma Linda University Electronic Theses, Dissertations & Projects

Dentists have long been challenged with finding an esthetic yet durable treatment option to restore badly carious anterior teeth. Veneered stainless steel crowns have become one of these options, but these restorations often return with the veneer fractured. To help restore esthetics, the crown may either be replaced or the veneer must be repaired. The purpose of this study was to evaluate the use of three bonding agents (PQ1, C&B Metabond, and Panavia) and one restorative material (Filtek Z250, 3M) in the repair of these fractured stainless steel crown veneers. The clinical significance is to determine the best methods of …

Accuracy Of The Indirect Method Evaluated By Mercury Micromeasurement, Estol C. Pruett

Loma Linda University Electronic Theses, Dissertations & Projects

Although the indirect method for preparing dental castings has been in use for over forty-five years, very little information has appeared in dental literature relative to its accuracy. The development of a precise and quantitative method for determining the adaptation of wax patterns or castings was necessary before such an evaluation could be considered valid. It was felt the Mercury Micromeasurement test, devised in 1958 by Hollenback, should meet these requirements. A description of the test had been published. However, at the time the project was begun, no data had appeared in the literature.

In order to establish a standard …