Dentistry Commons^™

The Effect Of Tooth Presence On Identification Of Tooth Socket Lamina Dura Surface: A Cbct Study, Morse Stonecypher

Loma Linda University Electronic Theses, Dissertations & Projects

Aim: The accuracy in identifying anatomical landmarks on CBCT images can be affected by the presence of surrounding anatomical structures with similar radiodensity. The purpose of this study was to evaluate the effect of the presence of tooth structure on the accuracy in identifying the lamina dura surface, facial bone surface, facial and lingual bone margins, socket apex, as well as in facial bone thickness measurement. Materials & Methods: Three fresh cadaver heads were scanned using a NewTom 5G CBCT at 0.100 mm voxel size at three time-points: before extraction (T1), after extraction and reinsertion (T2), and after tooth removal …

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, …

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 …

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. …

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 …

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 …

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 …

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 …

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 …

Using Cone Beam Computed Tomography To Identify A Prediction Model For Obstructive Sleep Apnea, Jodi Parker

Loma Linda University Electronic Theses, Dissertations & Projects

Introduction: Obstructive Sleep Apnea (OSA) patients have increased risk of morbidity and mortality. Early diagnosis may reduce morbidity and mortality. Prediction of OSA from imaging may help to identify OSA patients earlier in life. CBCT can be used for OSA diagnostic imaging due to its three-dimensional (3D) visualization of the upper airway and craniofacial complex. Magnification associated with conventional 2D radiography is eliminated with CBCT, and radiation to the patient is significantly less than previous modalities used to measure craniofacial & airway measurements associated with OSA. During a CBCT scan, the patient's image is taken supine, rather than the upright …

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 …

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 …

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 …

The Comparative Radiopacity Between Primary And Permanent Teeth, Robert C. Lee

Loma Linda University Electronic Theses, Dissertations & Projects

Purpose: This in vitro study compared the radiopacity between human primary and permanent enamel and dentin. It also compared the radiopacity between human anterior and posterior teeth.

Methods: Extracted primary and permanent teeth were used in this study. One mm enamel and one mm dentin slices were cut from each extracted tooth. Radiographs were taken of each enamel and dentin specimen 1 mm in thickness along with an aluminum step-wedge using procedures specified in International Standards Organization (ISO) 4049:2000. A densitometer was used to measure the Optical Density (OD) of the radiographs of the specimen and the accompanying aluminum step-wedge. …

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 …

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 …

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 …

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 …

Reproducibility Of Two Non-Consecutive Scans Using A Newtom 3g; In Vitro Model, Hyoung Jin Park

Loma Linda University Electronic Theses, Dissertations & Projects

Purpose: The aim of this study was to evaluate the reproducibility of mineral density measurement expressed in Hounsfield Units (HU) using a phantom device with known mineral densities and the NewTom 3G Cone Beam Computerized Tomography (CBCT).

Materials and Methods: A phantom device made of 21 HA cylindrical disks with known densities was fabricated. The phantom was scanned in 6, 9, and 12 inch fields of view using a NewTom 3G CBCT. The scans were repeated at non-consecutive sessions. Volumetric data in each of the scans were formatted to DICOM images. HU values of the regions of interest were retrieved …

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 …

Implant Success In Distracted Bone Versus Autogenous Bone-Grafted Sites, Jeffrey Allan Elo

Loma Linda University Electronic Theses, Dissertations & Projects

Endosseous implants are the treatment of choice for restoring function and reconstructing edentulous areas of the maxilla and mandible. Alveolar defects can be reconstructed by either distraction osteogenesis or autogenous bone grafting. After alveolar reconstruction, endosseous implants are used to support and retain the prosthesis for restoration of form and function. We retrospectively analyzed the success rates of endosseous implant placement in distracted versus autogenous bone graft reconstruction sites in our patient population at Loma Linda University Medical Center, Department of Oral and Maxillofacial Surgery. 82 consecutive patients requiring alveolar augmentation prior to implant placement were evaluated. All patients were …

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 …

Effects Of Diabetes Mellitus On The Healing Of The Dental Pulp, Stuart Evan Garber

Loma Linda University Electronic Theses, Dissertations & Projects

Diabetes Mellitus (DM) has been implicated as a factor affecting healing. The purpose of this study was to use the healing of experimentally exposed pulps subsequent to pulp capping as a model to determine the effect of DM on healing.

Twenty-two Sprague-Dawley rats were divided into two groups of eleven animals each. In one group, DM was induced by injection of 70 mg/KG of streptozotocin. In the other group, the animals were injected with sterile saline. Under anesthesia with Ketamine and Xylazine, the pulps of the maxillary first molars of all rats were exposed using a 1/16 round bur under …

Influence Of Keratinized Mucosa, Bone Dimensions On Mucosal Recession And Bone Loss, Jeanette Keng Ling Chua

Loma Linda University Electronic Theses, Dissertations & Projects

Background: To accomplish successful esthetic outcome, it would be an advantage if some pre-implant placement conditions could be identified which would predict soft and hard tissue outcomes post-implant placement. This study was designed to evaluate the influence of 1) height of mid-buccal keratinized mucosa at implant surgery and 2) thickness of mid-buccal bone after osteotomy on the amounts of mid-buccal mucosal recession and bone loss during the first year after implant treatment. This report presents the initial 3-month follow-up.

Materials and methods: Nine patients scheduled for surgical placement of a total of 11 single-staged implants, without adjacent teeth and planned …

Vital Pulp Therapy With Mineral Trioxide Aggregate: An Outcomes Study, Heather H. Lauer

Loma Linda University Electronic Theses, Dissertations & Projects

Mineral trioxide aggregate (MTA) is used in a variety of endodontic procedures. MTA is proven to provide good marginal adaption to dentin, to be biocompatible, and to stimulate dentin bridge formation through animal studies. These properties make MTA a potentially useful material to be used in vital pulp therapy. Clinical data on the use of MTA as a vital pulp medicament is sparse. The purpose of this study was to evaluate the clinical outcome of vital pulp therapy using MTA as the pulp medicament. Inclusion criteria for patient selection for recall was based on pulp treatment necessary from carious pulp …

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 …

Stability Of The Miniscrew-Bone Interface: Reverse Torque Values In Rabbits, Daniel John Drye

Loma Linda University Electronic Theses, Dissertations & Projects

Introduction: Miniscrews are used in orthodontics as practical temporary anchorage devices (TAD's). The purpose of this animal study was to measure reverse torque values for Absoanchor 1.2 mm and Micerium 1.5mm miniscrews at 0, 2, and 12 weeks under loaded and unloaded conditions.

Methods: Ninety-six miniscrews were placed in the femora of twelve rabbits and allowed to heal for either two or twelve weeks. Half of the fixtures were loaded immediately with NiTi open coil springs producing a force of 150-200g and the other half served as unloaded controls. For each of the healing times, two and twelve weeks, …

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™. …

The Outcome Of Mta As A Root End Filling Material: A Long Term Evaluation, Christopher M. Sechrist

Loma Linda University Electronic Theses, Dissertations & Projects

Periradicular surgery is a viable option to save natural teeth when non-surgical treatment fails or when endodontic retreatment is not feasible or contraindicated. Laboratory and animal studies have demonstrated that MTA is biocompatible, provides an excellent seal against penetrating bacteria, and promotes hard tissue healing. The purpose of this study was to provide long term (>3 years) clinical evidence for its use as a root-end filling material in endodontics. The clinical records of 294 patients who had MTA used during endodontic treatment from 1996 to 2001 were reviewed. From these, 75 patients whose root end cavities had been filled …

Treatment Outcome Of Root Perforations Repaired With Mineral Trioxide Aggregate, Stephen H. Paik

Loma Linda University Electronic Theses, Dissertations & Projects

Root perforations during root canal therapy have a significant negative impact on long-term prognosis of teeth. Proper treatment is critical in managing these accidental procedures. Laboratory and animal studies have demonstrated that Mineral Trioxide Aggregate (MTA) is biocompatible, provides an excellent seal against penetrating bacteria, and promotes hard tissue healing. The purpose of this study was to determine the long term treatment outcome of root perforations repaired with MTA.

Ninety-nine records from the Graduate Endodontic Clinic at Loma Linda University School of Dentistry from 1996 to 2001 were reviewed. Clinical and radiographic evaluations were completed. Three independent examiners evaluated digitized …