Orthodontics and Orthodontology Commons^™

The Role Of Gsk3 Alpha And Beta In Embryonic Craniofacial Development, Harman Jassar

Electronic Thesis and Dissertation Repository

Background: The GSK-3 genes (Gsk3a and Gsk3b) have been known to affect many cellular processes and signaling pathways some of which are implicated in the growth and development of the craniofacial skeleton.

Aim: The purpose of this study was to assess the effect of chondrocyte-specific deletion of Gsk3a and Gsk3b on the size of the mandible and craniofacial skeleton in embryonic mice.

Materials & Methods: Mice were bred to generate cartilage-specific Gsk3a and Gsk3b KO mice. On embryonic day 18.5 (E18.5) the offspring were gathered by caesarian section. Whole mount skeletal staining was completed on the specimens using …

Persistent Palatal Hypertrophy Associated With Rapid Maxillary Expansion Procedure: Report Of A Rare Case, Mehmet Melih Omezli, Damla Torul, Tolunay Avci

BioMedicine

Maxillary transversal deficiency (MTD) is a common skeletal problem. If not treated on time, MTD evolve to a more complex malocclusion. This problem can affect facial growth and development. Rapid maxillary expansion (RME) procedure frequently used for the management. This technique is usually successful in young individuals but as the age advances and the articulations of the maxilla with surrounding facial bones get more rigid, it becomes ineffective. Undesirable side effects or results have been reported after use of RME in skeletally mature patients such as buccal tipping of posterior teeth, extrusion, periodontal tissue recession, fenestration of buccal cortex, necrosis …

Changes In Airway Volume In Adult Patients Following Orthodontic Treatment With Premolar Extractions Versus Non-Extraction, Sunny Jisun Lee, Allison Kawata, Hayoung Michael Shin, David Chambers, Joorok Park, Heesoo Oh

Excellence Day

Recent concerns about the prevalence of obstructive sleep apnea (OSA) and its negative sequelae have led to investigations of how manipulation of the dentofacial complex may affect airway problems. CBCT can be used to measure airway dimensions of patients. Extraction of premolars is indicated as part of orthodontic treatment for patients who have severe crowding or protrusion of incisors. Some have suggested that the reduction in arch circumference after premolar extraction would lead to decreased airway volume, which may predispose a patient for sleep disordered breathing (SDB). The purpose of this study was to determine whether there is a significant …

Changes In Cephalometric Measurements In Adult Patients Following Orthodontic Treatment With Premolar Extractions Versus Non-Extraction, Byron Chou, David Dang, Adrienne Joy, David Chambers, Joorok Park, Heesoo Oh

Excellence Day

Extraction of premolars is indicated as part of orthodontic treatment for patients who have severe crowding or protrusion of incisors. CBCT can be used to locate cephalometric landmarks in 3D. The purpose of this study was to determine whether there are differences in sagittal, transverse, and vertical skeletal and dental dimensions for adult patients who were treated with premolar extractions in conjunction with orthodontic treatment compared to those who received orthodontic treatment without extractions.

Condylar Degeneration In Patients With Dental Open Bite Versus Skeletal Open Bite Utilizing Cbct, Alex Rauchle, Alston Trinh, Linda Phi, Brad Albertson, Joorok Park, Heesoo Oh

Excellence Day

Idiopathic condylar resorption (ICR) is a condition in which either one or both condyles undergo degeneration. Bilateral TMJ involvement presents as a clockwise rotation of the mandible in the posterior-inferior direction, resulting in an anterior open bite. The purpose of the study was to assess TMJ condylar degeneration in dental open bites compared to skeletal open bites.

Dexamethasone Regulates Gene Expression Induced By The Mechanosensitive P2x7 Receptor In Osteoblasts, Meena Na

Electronic Thesis and Dissertation Repository

Orthodontic tooth movement involves activation of osteoblasts and osteoclasts in response to mechanical forces. Extracellular nucleotides, released in response to mechanical stimuli, signal through P2 receptors in osteoblasts. P2X7 receptors are ATP-gated cation channels implicated in mechanotransduction in bone. Corticosteroids such as dexamethasone exhibit anti-inflammatory effects and their chronic use has been linked to serious side-effects such as osteoporosis. We investigated gene expression following P2X7 receptor activation with benzoylbenzoyl-ATP (P2X7 receptor agonist) in osteoblast precursor cells in the presence or absence of dexamethasone. We hypothesized that dexamethasone inhibits the ability of ATP to stimulate the expression of anabolic (bone forming) …

Frictional Forces Of A Fixed, Esthetic Orthodontic Appliance System, Brady Michael Nance

UNLV Theses, Dissertations, Professional Papers, and Capstones

Purpose: The demands of an all esthetic fixed orthodontic appliance system are ever increasing in today's world. Frictional values of an esthetic, fixed orthodontic appliance system are needed to evaluate their clinical effectiveness for orthodontic treatment. The aim of this study is to evaluate the frictional values of various esthetic orthodontic archwires ligated to an esthetic orthodontic bracket.

Methods: Three types of stainless steel and nickel titanium alloy (niti) esthetic orthodontic archwires (epoxy, poly, plastic) in four sizes (.016, .018, .017 x .025, .019 x .025 inches) were ligated to both a stainless steel bracket system and a ceramic (esthetic) …

Hydrolysis Of Amelogenin By Matrix Metalloprotease-20 Accelerates Mineralization In Vitro, Vuk Uskoković, Feroz Khan, Haichuan Liu, Halina Ewa Witkowska, Li Zhu, Wu Li, Stefan Habelitz

Pharmacy Faculty Articles and Research

In the following respects, tooth enamel is a unique tissue in the mammalian body: (a) it is the most mineralized and hardest tissue in it comprising up to 95 wt% of apatite; (b) its microstructure is dominated by parallel rods composed of bundles of 40 – 60 nm wide apatite crystals with aspect ratios reaching up to 1:10,000 and (c) not only does the protein matrix that gives rise to enamel guides the crystal growth, but it also conducts its own degradation and removal in parallel. Hence, when mimicking the process of amelogenesis in vitro, crystal growth has to …

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 …

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 …

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 …

Condylar Remodeling After Distraction Osteogenesis And Bilateral Sagittal Split Osteotomy, Robert Barker Hoffman

Loma Linda University Electronic Theses, Dissertations & Projects

The present pilot study is a histological evaluation of mandibular condyles taken from minipigs that underwent either traditional mandibular advancement (bilateral sagittal split osteotomy), or a distraction osteogenesis procedure to advance the mandible. One pig received a bilateral sagittal split osteotomy with an immediate mandibular advancement of 14 mm, while another pig underwent distraction osteogenesis consisting of a gradual advancement of 2 mm per day to advance the mandible the same distance. The control animal received no surgery.

In the present study, the mandibular condyles of the three pigs (2 control, 2 bilateral sagittal split osteotomy, and 2 distraction osteogenesis) …

Comparison Of Bracket Bond Strength By Total, Self-Etch And Laser Treatment, Kyo Sung Shawn Kim

Loma Linda University Electronic Theses, Dissertations & Projects

Laser etching of enamel surfaces alters the physical and chemical characteristics of the enamel. These changes in characteristics enhance the bonding to enamel. The purpose of this study was to compare the shear and tensile bond strength of Er,Cr:YSGG hydrokinetic laser system (Biolase) with 37% phosphoric acid and self etching primer 30 minutes and 72 hours after bonding. Four different laser power output setting was observed: 1.5W, 2.0W, 2.5W, and 3.0W. Two hundred forty bovine teeth free of defect, caries, and dentin exposure were mounted in acrylic resin and divided into 24 groups of 10 teeth. Sixteen groups of 10 …

A Bond Strength Comparison Of Led And Halogen Light Curing Units, John Richard Kavanagh

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this research was to compare the tensile bond strength of orthodontic flat based buttons bonded to bovine teeth with four commercial light-emitting diode (LED) curing lights and one conventional quartz tungsten halogen (QTH) curing light.

The dental market has recently been introduced to a number of commercially available light-emitting diode (LED) curing lights. Tensile bond strength was evaluated for LED curing lights (Rembrandt® Allegro^TM, Den-Mat Corp, Santa Maria, CA), (LEDemetron, Kerr/Demetron Corp, Danbury, Conn), (Ortholux LED, 3M^TMESPE^TM, St. Paul, MN),and (FLASH-lite 1001, Discus Dental, Culver City, CA) are compared with one …

The Histological Effects Of Mandibular Distraction Osteogenesis On Rabbit Condyles, Eunice Jungmin Hong

Loma Linda University Electronic Theses, Dissertations & Projects

The present study is a histological evaluation of condyles taken from rabbits that underwent either a midline or paramedian distraction osteogenesis procedure on the mandibles. Fifteen rabbits were originally operated on and eight of these fifteen successfully made it through both the distraction osteogenesis procedure and the 1 month holding period that followed. There was one control animal.

In the present study, the condyles from these nine rabbits (1 control, 2 midline distraction osteogenesis, 6 paramedian distraction osteogenesis) were prepared for histological evaluation (18 total). Step serial sections were cut along the coronal plane and the sections from the anterior …

Synovial Fluid Hydrostatic Pressure In The Tmj After Mandibular Advancement In Sus Scrofa, Samuel A. Demirdji

Loma Linda University Electronic Theses, Dissertations & Projects

Mandibular advancement is performed in patients routinely by traditional bilateral sagittal split osteotomy (BSSO) or less commonly by distraction osteogenesis (DO). The influence of mandibular advancement on the temporomandibular joint (TMJ) is well recognized but not fully explored. This study involved the direct measurement of synovial fluid hydrostatic pressure (SFHP) in the TMJ after mandibular advancement by either BSSO or DO in two male mature minipigs, Sus scrofa. Titanium pressure transducers were inserted into the right superior temporomandibular joint spaces of the minipigs and the measurements were displayed on an AC/DC amplifier. The first minipig underwent BSSO, which involved immediate …

Optimum Bonding Time Of Four Different Curing Lights, Nathan Don Cotten

Loma Linda University Electronic Theses, Dissertations & Projects

With the development of new high-intensity curing lights, the time required to bond orthodontic brackets is steadily decreasing. The objective of this study was to determine the optimum curing time for bonding orthodontic brackets using four different visible curing lights (Standard Optilux 501, High Intensity Optilux 501 with Turbo Tip, Virtuoso Plasma Arc, and ESPE LED light). This study also tested the new generation of light emitting diode (LED) lights to determine if they can be used for bonding orthodontic brackets. Three hundred freshly extracted bovine teeth were mounted in acrylic resin and divided into 20 groups of 15 teeth …

Post-Treatment Evaluation Of Isometric Function Of The Elevator Muscles, Margaret Barbara Kowalczyk

Loma Linda University Electronic Theses, Dissertations & Projects

This study mainly examined neuromuscular function, occlusal index, and centric relation-centric occlusion (CR-CO) discrepancy of 23 orthodontically treated patients. Phase I, craniofacial anomalous, and orthognathnic surgery cases were excluded from the study. Record taking was done in 2 sessions: (1) at the time of deband and (2) 3-4 months later. Records taken at each session included facial and intraoral photographs, impressions, CR wax bites, a facebow, and surface EMG (sEMG) recordings.

For the sEMG recordings, electrodes were placed on the upper hyoid, masseter, and anterior temporalis muscles. Subjects were asked to perform numerous tests; these included baseline, clenching to test …

A Pilot Study Testing A Proprietary Sealant For Plaque Reduction, Jennifer Rowland

Loma Linda University Electronic Theses, Dissertations & Projects

Enamel demineralization due to increased plaque accumulation is a well-recognized problem associated with fixed orthodontic appliances. The purpose of this study was to evaluate the efficacy of a proprietary product to be marketed by 3M Unitek for the reduction of plaque accumulation and thereby reduce enamel demineralization.

Sixty four bovine teeth were divided equally into an untreated control group and a group treated with the proprietary sealant product. Both groups were subsequently immersed in a Streptococcus mutans culture. Plaque deposits from each group were removed, suspended in trypticase soy broth, serially diluted, and plated on trypticase soy agar at 1, …

In Vitro Plaque Formation On Orthodontic Resin Sealants, Leland W. Pack

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to examine in vitro plaque formation on sealant coated enamel. The plaque growth on different types of sealants placed on enamel was compared to each other and to an unsealed enamel control. The antimicrobial properties of sealants were also studied.

Sealant coated bovine enamel disks were immersed in a S. mutans culture medium for four days. The amount of bacterial plaque formation was quantified by removing the deposit, suspending it in solution with subsequent serial dilution. Aliquots of the dilutions were then spread on blood agar plates and incubated for 48 hours. The number …

A Non-Human Primate Model For Evaluating A Fenestration Corticotomy Technique, Philip G. M. Khng

Loma Linda University Electronic Theses, Dissertations & Projects

A study model has been designed to evaluate the effectiveness of a new fenestration corticotomy procedure in two non-human primates Macaca fasicularis.

The objective of this study was to evaluate the efficacy of a new conservative corticotomy procedure to facilitate dental translation using fenestrations. This pilot study compared treatment and control quadrants of each individual animal's maxilla and mandible with both having the same retraction appliance and force on the 2nd premolar following extraction of the 1st molars. The null hypothesis stated that there was no significant statistical difference between the new conservative corticotomy procedure (fenestrations) when compared with …

An Evaluation Of Surface Enamel Damage Following The Debonding Of Ceramic Brackets : A Follow-Up Study, B. Scott Hood

Loma Linda University Electronic Theses, Dissertations & Projects

To evaluate surface enamel damage after debonding ceramic brackets using their manufacturer's recommended methods, sixty four bicuspid teeth were bonded with three different types of ceramic brackets and one type of metal bracket. All the brackets tested utilized mechanical retention only. The brackets were debonded in the mouth seven to ten days after bonding, extracted and evaluated with a scanning electron microscope. The study concluded that: 1) all brackets alter the surface enamel, 2) there is a significant difference in surface enamel damage between the metal bracket and the ceramic brackets utilizing a tensile debonding method, 3) there is no …

New In Vivo And In Vitro Techniques For Quantification Of Lateral Force Levels That Cause Implants To Fail : A Progress Report On Monkey Research, V. Leroy Leggitt

Loma Linda University Electronic Theses, Dissertations & Projects

Two new techniques for quantification of forces generated by an expansion screw apparatus placed between pairs of cylindrical endosseous titanium implants are described, along with preliminary data gained from their use in Macaca rhesus monkeys. Strain gages were bonded to the expansion apparatus and were calibrated either directly by micro load cell, or indirectly by Instron Machine to reflect the applied force.

Immediate loads of up to 6 kilograms have been applied to the implants with no increase in mobility as verified by a Periotest device. No previous studies on the orthodontic uses of implants have evaluated in vivo forces …

Histomorphometric Analysis Of Primate Periodontal Tissues Following Corticotomy In Orthodontics, Wuiteng Koh

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to evaluate the prevalence of specific cell types and structures at the active tooth movement site in corticotomized and non-corticotomized specimens obtained from a previous study, and to consider the hypothesis that corticotomy facilitated orthodontics is efficacious due to an inflammatory response rather than tooth-bone block movement. Specimens from 3 monkeys, each of which had a treatment and control quadrant in each arch, were sectioned, mounted on glass slides, and stained with Giemsa, haematoxylin, and Safranin stains. A histomorphometric analysis was performed with DataVoice™, a voice activated computer system which allowed for digitization of …

Electromagnetic Field Variations In The Activation Of Bone Cell Synthesis, Gary Ketcherside

Loma Linda University Electronic Theses, Dissertations & Projects

[Abstract Not Included]

A Non-Human Primate Model For Studying Corticotomy-Facilitated Orthodontic Tooth Movement, R. David Rynearson

Loma Linda University Electronic Theses, Dissertations & Projects

This study was undertaken to test the hypothesis that a corticotomised tooth moves as a tooth-bone unit when under orthodontic force. A non-human primate model was designed to test the hypothesis. The non-human primate selected was Macaca fasicularis. Three adult males with erupted third molars were chosen so that extrapolation could be made to the adult human. The methods employed included the following: 1) Each animal had one treatment quadrant and one control quadrant per arch; 2) Pre-op and post-op study models were made; 3) All 2nd premolars, 2nd molars, and 3rd molars were banded; 4) A full-thickness flap …

Effects Of Lateral Mandibular Expansion On Mandibular Morphology In The Growing Rat : A Comparative Study Of Treatment Effects With Orthopaedic And/Or Surgical Procedures, Eric Looi

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to investigate the effects of mandibular expansion by orthopaedic and surgical procedures in the growing rat mandible.

Sixty-four 35 day old Sprague Dawley Harlan rats were divided into four groups of 16 rats each and categorized as the control, orthopaedic expansion, surgery without graft and surgery with graft respectively. Prefabricated appliances were used for orthopaedic expansion of the mandibles and maintaining surgical expansion at the symphysis in the respective groups. Oxytetracycline were given intraperitoneally to mark areas of bone remodeling. Half the number of rats from each group were sacrificed at the end of …

Stability In Mechanical Expansion Of The Maxilla With Surgical/Mechanical Expansion Of The Mandible In An Adult Baboon, Robert D. Mitchell

Loma Linda University Electronic Theses, Dissertations & Projects

Expansion of the maxilla at the midpalatal suture has had much investigation and is a recognized option in orthodontic therapy. Lateral expansions of the mandible through surgical separation at the symphysis have been done in animal studies. A combination of these procedures has not yet been done together.

The purpose of this study was to expand both the maxilla and the mandible of a baboon simultaneously while maintaining occlusion. The amount of expansion and stability was studied using photographs, models, cephalograms, and tetracycline bone labels using U.V. microscopy.

A young adult baboon with full dentition and normal occlusion was used. …

The Effects Of Orthodontic Repositioning Into A Surgically Expanded Site On Bone Formation And Tooth Mobility In A Baboon, Anthony B. Lier

Loma Linda University Electronic Theses, Dissertations & Projects

For sometime, expansion of the maxillary arch, by means of surgical and mechanical procedures, have been acknowledged with minimal attention directed toward the mandible. In this pilot study a surgical technique was employed in separating the mandible, A-P, at the symphysis. The interosseous void, approximately 10 mm., was then filled with autogenous bone marrow collected from the greater trochanter and the crest of the ilium.

The surgical site was then maintained for a period of eight (8) weeks with the aid of a precast chromium-cobalt splint and titanium mesh placed intradentally and at the symphysis, respectively. Following the stabilization period …

Orthognathic Surgical Expansion Procedure Of The Mandible Of Female Baboon Papio Sp?, Willis L. Schlenker

Loma Linda University Electronic Theses, Dissertations & Projects

Expansion of the maxillae is a well recognized procedure in orthodontics. Little is known about Mandibular Expansion. This project is a pure research of the possibility of expanding the mandible laterally at the symphysis on a baboon.

The symphysis was cut A-P and expanded laterally 11 mm, then held and stabilized with a titanium mesh work screwed to the inferior border of the mandible. The defect area was filled with a bone graft of marrow and cancellous bone fragments taken from the greater trochanter and the crest of the ilium. New bone did fill in the defect and the expansion …