Orthodontics and Orthodontology Commons^™

Civic Attitude And Activity Of Loma Linda University Dental Graduates, Gregory W. Olson

Loma Linda University Electronic Theses, Dissertations & Projects

Introduction: Dentistry is regarded as a profession and granted certain privileges, such as self-regulation. Associated with this status are stated and implied responsibilities which are widely debated. In recent years, dental professionalism seems to be on the decline. Evidence cited includes access-to-care issues and decreased public trust in dentists. In response, academia and professional organizations have developed curricula and statements intended to bolster professionalism. Meanwhile little is known about practicing dentists’ attitudes or participation in health-related civic matters. Objectives: This study seeks to examine the importance Loma Linda University (LLU) dental graduates place on public roles, their reported participation in …

The Influence Of Outdoor Air Quality On Vertical And Transverse Dental Dimensions, Vanessa Jenee Kaplan

Loma Linda University Electronic Theses, Dissertations & Projects

Introduction: Ambient air pollution exposure is significantly associated with increased posterior crossbite tendency. Purpose: The objectives of this study were to assess whether there was an association between exposure to ambient air pollution and skeletal and dental measurements of vertical and transverse dimension among adolescents in a clinical cohort in Southern California, and to determine what methods may be best suited for use in future research. Materials and Methods: 179 subjects’ addresses were geocoded and ambient air pollution exposure was calculated based on the Environmental Protection Agency’s (EPA) air quality and emissions databases. Vertical and transverse measurements made from subjects’ …

Facial Type Analysis Comparison Between Mri, Cbct, And Lateral Cephalometrics, Matthew A. Sanders

Loma Linda University Electronic Theses, Dissertations & Projects

Introduction: Single Cephalometric measurements are comparable between Cone Beam Computed Tomography (CBCT), Magnetic Resonance Imaging (MRl) and Conventional Lateral Cephalometric (LC) imaging methods. This study evaluated the agreement between the three imaging methods in facial type analysis (using a composite of 5 cephalometric measures).

Methods and Materials: Twenty-two subjects participated in this study. Cranial images were generated via three modalities: LC, CBCT and MRl. Cephalometric landmarks were identified on the three images per subject and a facial type analysis performed. An equally weighted facial type calculation composed of 5 cephalometric measurements (facial axis, facial depth, mandibular plane, lower face height, …

Work Of Fracture In Ceramic Bracket Bonding Systems, Tye A. Roylance

Loma Linda University Electronic Theses, Dissertations & Projects

Introduction: Work of fracture (WOE) is a method of analysis of the toughness or resilience of a bracket bonding system. It is an indication of a bracket bonding systems ability to withstand forces in the mouth below the force at which failure occurs. Work of fracture gives an indication of how much abuse the bracket/bonding system can withstand and still maintain an adequate adhesion to the tooth surface. This analysis incorporates shear bond strength and displacement and is determined in part by the elasticity and resilience of the specimen being studied.

Materials and Methods: One hundred and eighty bovine teeth …

Correlating The Slope Of The Vomer With Cephalometric Vectors Of Facial Growth, Ryan Michael Pulfer

Loma Linda University Electronic Theses, Dissertations & Projects

It is important for orthodontists to have a basic understanding of the growth and development of the face. Scott's nasal septal cartilage theory proposes that the cartilage of the nasal septum proliferates along the anterior slope of the vomer bone by interstitial growth, simultaneously pulling and displacing the maxilla downward and forward. It is therefore logical to conclude that the vector of nasomaxillary growth has a geometric correlation with the anterior slope of the vomer bone.

There are no published studies comparing either the anterior or posterior slope of the vomer with any lateral cephalometric landmarks, the vectors of nasomaxillary …

Creating Prediction Models For Obstructive Sleep Apnea Based On Gender, Jeffrey Hwang

Loma Linda University Electronic Theses, Dissertations & Projects

Introduction: Obstructive sleep apnea (OSA) is a common chronic disorder that is characterized by repetitive episodes of airflow cessation or reduction occurring during sleep as a result of partial or complete upper airway obstruction. These recurrent events have a tremendous impact on the cardiovascular system with a multitude of dangerous consequences. Numerous studies have been conducted determining etiological risk factors for OSA including anatomical predictors which have been observed with multiple imaging techniques. Cone beam computed tomography (CBCT) is a low-radiation mode of imaging that can be used to accurately identify anatomical landmarks and measure craniofacial relationships and airway dimensions. …

Microct Study Of Critical-Sized Defects Restored With A New Rhbmp-2 Carrier, Joanne S. Kim

Loma Linda University Electronic Theses, Dissertations & Projects

Introduction: Regenerating bone in critical-sized maxillofacial osseous defects remains a challenge. The utilization of recombinant human bone morphogenetic protein-2 (rhBMP-2) to form new bone has been shown to be a promising alternative to autogenous bone grafts, and the development of a carrier matrix to effectively deliver the rhBMP-2 has been identified as the critical factor necessary for the successful clinical application of rhBMP-2. The objective of this study was to perform a microCT analysis to examine the density of reconstructed bone using different rhBMP-2 carriers in critical-sized defects.

Material and Methods: Critical-sized defects (approximately 2.5 cm) were created in the …

Effects Of Orthodontic Treatment On Social Perceptions, Sherry A. Caraveo

Loma Linda University Electronic Theses, Dissertations & Projects

Introduction: The purpose of this study was to record first impressions elicited by photographs of orthodontic patients before and after treatment to test the hypothesis that after treatment patients will elicit a more positive first impression.

Methods and Materials: Before (Tl) and After (T2) photographs of six orthodontic patients equally divided by gender and standardized for background facial attractiveness were selected. Three different malocclusions were represented: 1) Class 1 crowded, 2) Class 11 div 1, and 3) Class 111. 108 college students rated each photographed patient on three attributes: physical attractiveness, intelligence and social desirability. Participants recorded their responses on …

Effects Of Functional Appliances On The Tmj And Mandibular Length Of Skeletal Class Ii Patients: A Cone Beam Computed Tomography Study, David C. Lee

Loma Linda University Electronic Theses, Dissertations & Projects

Introduction: Functional appliances have been efficiently used in the treatment of Class II malocclusions caused by retrognathic mandibles. Cone beam computed tomography has enabled us to make more accurate linear measurements by eliminating superimposition of other structures and to analyze skeletal anatomic detail in all three planes of space. This retrospective study evaluated the osseous changes in the temporomandibular joint (TMJ) and length of the mandible in skeletal Class II malocclusion patients treated with the fixed functional appliances and compared measurements with Class I malocclusion patients treated with orthodontic mechanics that did not alter skeletal relationships.

Materials and Methods: Twelve …

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 …

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 …

Effects Of Functional Appliances On Pharyngeal Airway Dimensions: A Cone Beam Computed Tomography Study, Melissa K. Lee

Loma Linda University Electronic Theses, Dissertations & Projects

Introduction: Functional appliances are intended to correct by incremental advancement of the mandible for correction of skeletal Class 11 relationships. Similar in design to functional appliances, mandibular advancing devices (MAD) are used for obstructive sleep apnea (OSA) patients as they increase the size of the airway by drawing the tongue and soft palate forwards, and thus maintain its patency during sleep. It has been shown that significant increases in airway dimensions and decreases in airway resistance were gained in OSA patients while evaluated with a MAD in place. This retrospective study evaluated volumetric, cross-sectional area and linear changes in the …

Observer Reliability Of Cephalometric Landmark Identification On 3-D Mr Images, Michael S. Pollack

Loma Linda University Electronic Theses, Dissertations & Projects

Introduction: Cephalometric analysis is a cornerstone of orthodontic diagnosis, yet much information is lost when 3-dimensional structures are assessed with 2-dimensional methods. CBCT offers 3-dimensional imaging but at the cost of higher levels of ionizing radiation. Magnetic resonance imaging provides 3-dimensional imaging without ionizing radiation and additionally imparts visualization of soft tissue structures. Prior to employing MR images for cephalometric analysis, reliability of landmark identification must be assessed. The purpose of this study was to evaluate intra- and interobserver reliability in 3-dimensional landmark identification using MR images.

Materials and Methods: Fifteen cranial MR images (3.0 T, MP-RAGE) from subjects between …

Comparison Of Mandibular Alveolar Bone With Facial Type Using Cbct, Jason M. Loop

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to evaluate the relationship between facial type and cortical bone thickness (mm), cortical bone density (rHU) and trabecular bone density (rHU) in the mandibular alveolar bone. Twenty-five consecutive dolichofacial, 25 consecutive mesiofacial, and 25 consecutive brachyfacial patients with T1 lateral cephalograms and CBCT scans were used in this study. A Ricketts analysis was used to compute the VERT index for each patient. All statistical analyses were performed at the significance level of α = 0.05. The one-way ANOVA and LSD post hoc tests indicated there was a statistically significant relationship between facial type and …

Buccal Bone Changes Following Rapid Maxillary Expansion (Rmf), Long-Term Results, Elena S. Iacob

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to use Cone Beam Computed Tomography (CBCT) images to quantitatively evaluate buccal bone changes of maxillary first premolar (P1), second premolar (P2) and first molar (M1) shortly after Rapid Maxillary Expansion (RME) and at the end of orthodontic treatment, as well as to evaluate the variables that may be associated with the short-term and long-term changes. Forty-seven consecutive patients (25 males and 22 females) with a mean age of 14.5years and who required RME as part of their orthodontic treatment and had pre-RME (T1) and post-RME (T2) CBCT images available were used for the …

Cephalometric Analysis Using Magnetic Resonance Imaging, Wade A. Williams

Loma Linda University Electronic Theses, Dissertations & Projects

Purpose: The purpose of this study was to determine if T1-weighted 3D magnetic resonance images performed at 3.0 Tesla could be used to conduct routine orthodontic cephalometric analysis.

Methods: Three cranial imaging methods were compared using sixteen non-growing subjects (10 male and 6 female) who were not claustrophobic, did not have any metallic restorations on the distal of first molars, had no medical implants and the female subjects were not pregnant. Sagittal cranial images were produced by three methods: (1) a digital lateral cephalometric (LC) radiograph (Orthophos XG Plus, Sirona^TM, Bensheim, Germany), (2) a 12-inch FOV cone beam …

Orthodontic Mini-Implant Failure: Assessing The Relationship To Bone Quality Using Qcbct, Joshua Schneider

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to evaluate the cortical bone thickness (mm), cortical bone density (HU), and trabecular bone density (HU) of mini-implants sites in both the maxilla and mandible using QCBCT to determine if they had any effect on mini-implant failure rate. Patient characteristics (age, gender, facial type), mini-implant characteristics (date of placement, manufacturer, length, and diameter), and the mini-implant site (region) were also evaluated. One hundred and six mini-implants in 50 consecutive patients with complete patient records, CBCT information, and T1 radiographs were included in the study. Thirty-four of the 106 mini-implants were considered "failures" resulting in …

Recognizing A Dysfunctional Swallowing Pattern Using Surface Electromyography (Semg), Michelle F. Couto

Loma Linda University Electronic Theses, Dissertations & Projects

Purpose: The purpose of this study was to determine if a surface electromyography (sEMG) assessment of swallowing is better at identifying Oral Muscular Dysfunction (OMD) than a clinical evaluation (observation & digital palpation) of swallowing. The assessment was conducted on children ages 9 to 17, who were patients at the Orthodontic Department at Loma Linda University, School of Dentistry. Additionally, the prevalence of a “perceived” swallowing dysfunction was assessed.

Methods: This study included 39 randomly selected subjects from the orthodontic patients at Loma Linda University. Each subject’s “dry” swallow was evaluated using two separate methods: (a) sEMG and (b) digital …

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 …

Precision Of Temporary Anchorage Device Placement With 2d Vs. 3d Diagnostic Tools And Surgical Guides, Howard Lee

Loma Linda University Electronic Theses, Dissertations & Projects

Current methods of temporary anchorage device (TAD) planning and placement are performed by radiographic analysis in a two-dimensional plane that lends itself to inaccuracy secondary to variations in the angle from which the radiograph is taken, as well as the magnification of the radiographic image, resulting in an increased likelihood of placement errors. The purpose of this study was to compare a three-dimensional (3D) TAD planning and placement technique to a traditional two-dimensional (2D) technique. In the 2D group, periapical radiographs and pre-fabricated wire guides were used for planning and placement of TADs on five plastic models. For the 3D …

Influence Of Mandibular Fixed Retainers On Diagnostic Quality Of Cranial Mri, Norman E. Carter

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to evaluate the diagnostic quality of MR images taken on subjects with different types of orthodontic lingual retainers in place. The study provides guidelines and recommendations for use of lingual retainer materials in those patients who are or may potentially undergo routine magnetic resonance imaging. Ten subjects had impressions taken and models made for retainer tray fabrication. Removable trays with each lingual retainer material incorporated in them were fabricated from the models. Subjects underwent scans with each of the five test trays in place. T1 sagittal (T1), T2 axial (T2), gradient echo (GRE), and …

Distraction Of Heterotopic Bone Formed With Bmp-2 In A Rat Model: The Technique, Stacie Dawn Fenderson

Loma Linda University Electronic Theses, Dissertations & Projects

Multiple studies have shown that ectopic bone forms when bone morphogenic proteins (for example BMP-2 and BMP-7) and a collagen matrix are surgically placed in a rat model either orthotopically or heterotopically. Bone begins to form by the 14 day, and is at it maximum calcified state by the 21st day. The purpose of this study is to observe and quantify the effect of distraction osteogenesis on the ectopic bone. First, a preliminary procedure was performed by surgically placing a titanium cage into the back of a rat just caudal to the thoracic vertebrae. The anterior corners were sutured to …

Detection Of Simulated Apical Root Resorption Using Three Cone Beam Ct Machines, Marcus Paulson

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to determine orthodontists' ability to discriminate small differences of simulated apical root resorption (SARR) on extracted teeth, using the output from three cone beam computed tomography (CBCT) machines. Twenty-four unrestored maxillary anterior teeth exhibiting normal morphology, were collected. The teeth were scanned by three CBCT machines: 1) the NewTom 3G (AFP imaging, USA), 2) the iCAT (Imaging Sciences, USA) 3) and the MicroCAT II (Siemens Medical, USA). Using a sandblaster the apical portion of each tooth was reduced in 0.5 mm increments up to a total reduction of 1.5 mm. Each root modification was …

Variability In Selecting Lateral Cephalometric Landmarks In Two Cbct Image Modes, Dana Nguyen

Loma Linda University Electronic Theses, Dissertations & Projects

Purpose: The purpose of this study was to determine the variability of lateral cephalometric landmark selection in two cone beam computed tomography (CBCT) lateral cephalometric simulations: 1) a mean projection image (MPI) and 2) a serial sagittal slice image (SSSI).

Methods: A MPI is a two-dimensional (2D) image obtained from the NewTom 3G^TM CBCT that resembles the conventional lateral cephalogram. A SSSI is a 2D image also obtained from CBCT data, but is created by superimposing a series of selected thin sagittal slices containing the required cephalometric landmarks. This study compared the Ricketts and Steiner analysis of the MPI …

Influence Of Common Orthodontic Appliances On Magnetic Resonance Imaging, Joseph Matthew Elison

Loma Linda University Electronic Theses, Dissertations & Projects

Magnetic resonance imaging (MRI) is an essential diagnostic tool in modern medicine. Conditions such as cerebral vascular accidents, epilepsy and other seizure disorders, autism, cancer, migraine and cluster headaches benefit from its use. It has been discovered that 4-10% of all children and adolescents will experience a seizure at some point (Hauser, 1994) and MRI is one of the most common imaging modalities for seizure and epilepsy diagnosis. Unfortunately, some orthodontic materials cause distortion on MR images. Radiologists would probably require the removal of any distortion-causing orthodontic appliance prior to MR imaging. It is questionable whether radiologists would be comfortable …

Dynamic Determinants Of Incisal Display, Shawn Paul Pesh

Loma Linda University Electronic Theses, Dissertations & Projects

The principal objective of this study was to use computer aided design (CAD) to better illustrate and quantify the relationship of mandibular arch depth, mandibular arch width, overbite, and overjet in the presence of mandibular dental crowding. To date, there has been no research examining how changes in the mandibular arch limit the orthodontist's ability to control overbite and overjet. Understanding how to effectively manage overbite and overjet are crucial to the clinician's ability to manipulate incisal display. Polyvinyl siloxane impressions of both maxillary and mandibular arches of a Caucasian patient were taken and used to pour dental stone models. …

Accuracy Of The Newtom 3g™ In Measuring The Angle Of The Articular Eminence, Rehana Khan

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to determine the accuracy of the Newtom 3G™ in determining the angulation of the articular eminence. The benefits of conducting this study were to provide additional uses for the standard records that are taken for the purposes of orthodontic treatment, as well as evaluate the Newtom 3G™ for accuracy in measuring the anatomy of the glenoid fossa. This study required 20 participants that volunteered to allow their records to be used. Records evaluated were the Newtom 3G™, impressions, and wax check bite registrations. The wax record was taken using the 'forced bite' technique to …

Ricketts And Steiner Analysis Using Newtom 3g™ Scout Images, James I. Gibson Iii

Loma Linda University Electronic Theses, Dissertations & Projects

NewTom 3G™ scout images have the general appearance of traditional lateral cephalometric radiographs. The purpose of this research was to determine if Ricketts and Steiner analyses could be accomplished on NewTom 3G™ scout images.

This was a retrospective study comparing the use of NewTom 3G™ scans in DICOM (Digital Imaging and Communications in Medicine) format to scout images from 25 consecutive patients of the Loma Linda University School of Dentistry Department of Orthodontics, three of these patients did not meet the inclusion criteria. The DICOM images were used to create controls. The controls and scout images were digitized using QuickCeph™. …

Magnification In Images Produced By Five Popular Digital Lateral Cephalometric Machines, Gretchen Marie Schnepper

Loma Linda University Electronic Theses, Dissertations & Projects

Modern digital lateral cephalometric images are produced by machines that vary in a number of critical features such as: 1) machine geometry, 2) movement (or lack of movement) of the x-ray source, 3) movement (or lack of movement) or x-ray detectors, 4) cephalostat geometry and 5) digital data manipulations by proprietary software. The purpose of this study was to evaluate the magnification characteristics of images produced by five commercial digital lateral cephalometric machines. These digital image magnification characteristics were then compared with images produced by an analog cephalometric machine. The two goals of this study were to: 1) measure the …

De-Bonding 4 Brands Of Ceramic Brackets With The Waterlase Er,Cr;Ysgg Laser, Carter A. Lane

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to determine if the Biolase Waterlase Er,Cr:YSGG laser could be used as a safe and effective tool to de-bond four currently available orthodontic ceramic brackets. Changes in interpulpal temperature, enamel surface conditions and the amount of time the laser was activated to debond (sic) the ceramic brackets were evaluated. Forty human maxillary premolars were divided into four groups of ten. Prior to direct bonding, all extracted teeth were impressed and duplicated in Araldite epoxy resin as the control surface. Identical techniques were used to bond 10 ceramic brackets from each manufacturer. Three of the …