Medicine and Health Sciences Commons^™

Influence Of Stainless Steel Orthodontic Brackets On Magnetic Resonance Imaging, Christian James Hoybjerg

Loma Linda University Electronic Theses, Dissertations & Projects

Introduction: Magnetic resonance imaging (MRI) machines provide 2D as well as 3D images that are excellent in contrasting soft-tissue in the maxillofacial region and are void of ionizing radiation. The drawbacks include the lack of depiction of cortical bony detail and image degradation caused by substances in the scanned area. Specifically, in the orthodontic field stainless steel brackets cause more distortion of MR images then any other bracket material. It is unknown what type of stainless steel alloy causes the most MRI distortion. The purpose of this study is to evaluate the degree of craniofacial MR distortion caused by various …

The Influence Of Work Of Fracture On Six Orthodontic Bonding Systems, Tyler S. Pritchard

Loma Linda University Electronic Theses, Dissertations & Projects

Introduction: Bonding is the primary method of attaching brackets to teeth in modem orthodontics. Thus, many studies have focused on the maximum shear bond strength values of orthodontic adhesives. In contrast, very little research has been performed considering the work of fracture of orthodontic bonding systems. Work of Fracture is defined as the area under the curve of a stress-strain graph. Previous shear bond strength studies measured the force necessary to produce bond failure. The purpose of this study was to measure the maximum shear force and displacement of six bonding systems and to calculate the work of fracture.

Materials …

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 …

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 …

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 …