Medicine and Health Sciences Commons^™

Current Theories On The Cell Biology Associated With Tooth Movement, Mohamadreza Yazdi

Loma Linda University Electronic Theses, Dissertations & Projects

This article discusses the current information on the mechanism of the biological signaling that takes place to bring about orthodontic tooth movement.

Currently, there are two general theories as to how orthodontic mechanical force is translated to biologically meaningful signals for the cells of the periodontium. These include a cellular-humoral response and a bioelectric response.

There are various mechanisms utilized by the cells of the periodontium to bring about the cellular-humoral response. These include: The activation of the cells of the immune system to synthesize and release specific chemicals (cytokines) which affect cell function, direct effects of mechanical force on …

Mandibular Asymmetry In Unilateral Class Ii Malocclusion : A Cephalometric Study, Raed Z. Moussa

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study is to evaluate skeletal and dental asymmetry in unilateral class II malocclusion. A study group of 25 unilateral subdivision patients was compared to 25 class I malocclusion patients serving as the control group. Submento-vertical and frontal radiographs were used for the evaluation. Symmetry was evaluated by comparing measurements between right and left sides for both groups and matching the middle points with the midsagittal axis. Statistical paired and simple t-test were used to evaluate the difference between the two sides for both groups. The measurements showed no significant skeletal and dental asymmetries except for three …

An Immediate Implant Stability And Pull-Out Study Comparing Two Different Surgical Techniques : Conventional Drilling Versus Trabecular Compaction : A Pilot Study, Yong Chang Choi

Loma Linda University Electronic Theses, Dissertations & Projects

Poor bone quality at an implant site and the lack of initial implant immobilization are considered the two main factors for first stage implant failure. Modalities are needed to improve the initial stability of implants in poor bone quality situations. The purpose of this study was to compare the immediate implant stability and the pull-out force of implants placed in fresh frozen human alveolar jaw bones by two different surgical techniques: 1) a conventional drilling technique and 2) a trabecular compaction technique. The initial lateral stability (assessed by Periotest values, PTVs), the uniaxial pull-out force (measured by Instron machine) and …

Evaluation Of Nitric Oxide In Respiratory Distress Syndrome, Kimberly S. Myruski

Loma Linda University Electronic Theses, Dissertations & Projects

Little is known of the effects of low concentrations of inhaled nitric oxide (NO) on pulmonary mechanics and lung volumes in premature newborn infants with lung disease. Cardiopulmonary function tests including blood gas analyses were obtained from eleven premature lamb models with respiratory distress syndrome to determine if compliance, airways resistance, tidal volume, functional residual capacity, and gas exchange were affected. The effect of inhaled NO on the direction of shunting through the ductus arteriosus was determined using echocardiography.

Twin lambs were cannulated with arterial and venous catheters and intubated with an endotracheal tube before delivery on gestational day 126-130 …

Alveolar Bone And Cementum Regeneration Following Periodontal Reconstructive Therapy : A Review Of Histologic Observations In Man And Experimental Animals, Karen E. Rodden

Loma Linda University Electronic Theses, Dissertations & Projects

Periodontal regeneration includes the formation of both alveolar bone and cementum. Studies reporting histologic evidence of healing following periodontal reconstructive therapy were reviewed to determine whether regeneration of these structures improves with increasing healing interval, and whether they regenerate independently or whether regeneration of one structure is dependent upon regeneration of the other. Additionally, the review addresses whether specific reconstructive modalities predictably yield increased amounts of regeneration. Differences in regenerative potential between humans, nonhuman primates, and canines were also examined. Results of over a decade of studies of periodontal reconstructive therapy were tabulated by family (human, nonhuman primate, and canine) …

Predicting Intentions Of Physical Therapy Students To Practice Primary Prevention, Sharon Potter Anderson

Loma Linda University Electronic Theses, Dissertations & Projects

Physical therapy (PT) has traditionally been a hands-on, tertiary-care field. Although the American Physical Therapy Association has mandated a broader perspective, little primary prevention is yet being reported in the U. S. An attitude change toward prevention must occur if physical therapists can be expected to become involved in preventive physical therapy. The purpose of this project was to determine predictors of physical therapy student intention to perform primary prevention with a questionnaire based on Ajzen's Theory of Planned Behavior. The theory uses attitude, subjective norm and perceived control to predict intention based on beliefs and strength of beliefs in …

The Experimental Verification Of The Efficacy Of Finite Element Modeling To Dental Implant Systems, Thomas D. Baiamonte

Loma Linda University Electronic Theses, Dissertations & Projects

The finite element method has previously been used to evaluate the stress distribution surrounding the dental implant to bone interface. However, prior finite element analysis models used have not been validated for the bone to implant interface. The objective of this study is to investigate whether the current Ansys finite element analysis model is an accurate biological representation of the observed clinical conditions. This will be accomplished by comparing data obtained experimentally of stress versus strain and the three dimensional computer generated finite element model.

The results indicate finite element method using the Ansys program for modeling is in agreement …

Posttraumatic Stress Disorder In Parents Of Traumatic Brain Injury Patients, Carol Farr

Loma Linda University Electronic Theses, Dissertations & Projects

Traumatic Brain Injury (TBI) produces cognitive, behavioral, and affective deficits with resulting problems such as improper social behavior, increased aggression, emotional, personality and characterological changes. The impact upon the survivor, the sibling, as well as the parental subsystem has been well documented in the literature. Post-Traumatic Stress Disorder (PTSD) has been diagnosed in several different types of trauma survivors, although rarely have individual psychological symptoms been studied in parents.

This research examined the possible vulnerability factors that are associated with TBI and their potential influence upon PTSD symptomology. Questionnaires were mailed to 266 parents of TBI patients with a response …

Examination Of The Predictive Validity Of Risk Assessment Screening, Patricia Mary Morressy

Loma Linda University Electronic Theses, Dissertations & Projects

Child Protective Services ( CPS) have been under growing pressure to implement risk assessment systems over the past ten years (Dueck, H. J., English, D.J., Depanfilis, and Moote, G.T. (1993). This emphasis has come largely from the increasing number of reported allegations of child abuse and neglect (Doueck, et. al.) However, increasingly individuals involved in custody battles use the CPS reporting system to retaliate against one another. Because these reported cases require the action of CPS, the increase in allegations has overburdened the system. As a result, resources have diminished and challenges to screeners to make accurate risk assessments have …

Factors Associated With Successful Long-Term Weight Loss Maintenance In Women, Renie Del Ponte

Loma Linda University Electronic Theses, Dissertations & Projects

Abundant literature exist on interventions for weight loss documenting the existence of a weight loss maintenance problem (Wadden & Bell, 1990; Kay man et al., 1990; Wadden et al., 1989). Very few individuals are successful at maintaining their weight loss for at least two years for reasons that are not clearly understood. This retrospective study examined factors, identified in a review of the scientific literature, shown to be associated with weight loss maintenance. A screening questionnaire was presented to all female patients (n=271) entering physician offices for routine health maintenance care from February 1, 1994 through June 30, 1994. Fifty-three …

Ornithine Decarboxylase And Polyamines In Perinatal Hypoxia, Satyaseelan Packianathan

Loma Linda University Electronic Theses, Dissertations & Projects

Hypoxic and hypoxic/ischemic episodes contribute to various neurological aberrations, learning disabilities, et cetera in surviving infants. Despite major advances in understanding the pathophysiology of hypoxia, the cellular basis for hypoxic-mediated injury remains poorly understood. In addition, the role of developmentally essential enzymes vis á vis their contributions, or lack thereof, to hypoxic-mediated injury has not been adequately investigated. In the series of studies comprising this dissertation, we tested the hypothesis that acute and/or chronic hypoxia affect the activity of omithine decarboxylase (ODC; E.C. 4.1.1.17), the developmentally essential enzyme in polyamine biosynthesis, in the fetal and newborn rat brain. Fetal and …

Periodontal Repair In Dogs : Evaluation Of Rhbmp-2 Carriers, Lauralee Nygaard

Loma Linda University Electronic Theses, Dissertations & Projects

This study evaluated candidate carriers for recombinant human bone morphogenic protein-2 (rhBMP-2) in periodontal reconstructive surgery.

Canine demineralized bone matrix (DBM), bovine inorganic crystallene bone matrix (Bio-Oss), bovine derived microfibrillar collagen matrix (Helistat), poly (D,L-lactide-coglycolide) micropaiticles (PLGA), and polylactic acid granules (Drilac) were used with rhBMP-2 (20 (µg/100 µl implant volume) in routine critical size canine supraalveolar periodontal defects. Contralateral defects in six beagle dogs were randomly assigned to receive: DBM/rhBMP-2, DBM-control, Bio-Oss/rhBMP-2, Helistat/rhBMP-2, PLGA/rhBMP-2, or Drilac/rhBMP-2, all with autologous blood except for Helistat and PLGA. Animals were sacrificed eight weeks post-surgery and block sections of the defects were processed …

A Comparison Of Retentive Strengths Of Two Types Of Inner Surface Treatments Of Orthodontic Bands, Jean M. Rathbun

Loma Linda University Electronic Theses, Dissertations & Projects

Band failure during orthodontic treatment results in a potential for decalcification and/or caries and may cause a prolonged treatment time. An increase in the bond strength at the cement/band interface would likely decrease clinical band failure. Sand-blasting and photo-etching have been suggested to improve this bond.

This study investigated the retentive strengths of untreated orthodontic bands, sand-blasted bands and photo-etched bands when cemented with glass polyalkenoate cement on extracted human molars. The sand-blasted bands and photo-etched bands were both found to have significantly stronger bond strengths (p

Space Closure Efficiency With Modified Ceramic Brackets : A Comparative Study, Kirk A. Specht

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to determine if the rate of extraction site closure was determined by the type of ceramic bracket used. A new ceramic bracket with a metal archwire slot was compared with a conventional ceramic bracket. Twenty patients were randomly assigned the metal slot ceramic bracket and conventional ceramic to one half of their maxillary arch respectively. The distribution was even left and right.

Retraction was started and completed on an 0.016" stainless steel round continuous archwire. One hundred gram sentalloy springs provided a uniform retraction force and were reactivated every four weeks to maintain a …

Modulation Of Neutrophil Functions By Neurotransmitters Implicated In Stress, Chok Ping Wan

Loma Linda University Electronic Theses, Dissertations & Projects

Stress has long been implicated in immune modulation. People under chronic stress have no change in the circulating basal levels of catecholamines while plasma levels of neuropeptide Y (NPY) are significantly increased. Sympathetic nerve fibers with NPY have been found to innervate immune organs. It was hypothesized that NPY might be a mediator in immune modulation in people under chronic stress. Human neutrophils were used as a model to study the effects of NPY alone or together with norepinephrine on the immune system. We now report that NPY modulates oxidative burst (OB) triggered by zymosan in human neutrophils while it …

Regulation Of The Insulin-Like Growth Factor System By Retinoic Acid In Human Osteoblast Cells, Yuehua Zhou

Loma Linda University Electronic Theses, Dissertations & Projects

Retinoic acid (RA) is an important regulator of growth and differentiation in many cell types, including bone. However, its effects on human osteoblast cell growth and differentiation have not been well studied. Therefore, I investigated the effect of RA on proliferation and differentiation of normal human bone cells (HBCs) and human osteosarcoma, SaOS-2 cells. RA decreased baseline as well as serum-stimulated proliferation in normal HBCs. To determine the effect of RA on differentiation, expression of several osteoblastic differentiation markers were studied. RA decreased type I procollagen mRNA levels and l,25(OH)₂D₃-stimulated osteocalcin and alkaline phosphatase (ALP) mRNA …

The Effects Of Rapid Palatal Expansion Therapy On The Periodontal Tissues Of The Central Incisors, Richard Gutierrez

Loma Linda University Electronic Theses, Dissertations & Projects

The periodontal structures around the maxillary central incisors in thirty-nine post-orthodontically treated patients, twenty-five of these patients had experienced Rapid Palatal Expansion (RPE), were examined to determine the periodontal consequences associated with two ways of managing the resultant diastema. In fourteen patients the diastema closure was assisted by elastomeric chain and in eleven patients the diastema closure was not assisted. Fourteen non-RPE orthodontically treated patients served as controls. Height of attached gingiva, gingival sulcus depth, attachment level, and alveolar bone level were recorded. One examiner, using calibrated techniques, performed all the measurements. The RPE groups and the control group all …

Plastic Deformation Of A Polycarbonate Bracket : Utilizing A New Testing Apparatus, Terri L. Alfred

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to investigate the plastic (permanent) deformation of a polycarbonate bracket (Miura, RMO) under the following different conditions: (1) untreated, (2) immersed in 37°C-water for 120 days, and (3) immersed in 60°C-water for 24 hours. Ten brackets for each condition were tested, with a total of 30 brackets tested. Each bracket was bonded to a metal mesh pad which was tack welded to a solid stainless steel ring. The assembly was placed under a loading frame. This loading frame removes variables such as bond adhesive strengths, distortion of a wire used to deform the bracket …

Experimental Peri-Implant Tissue Breakdown In Rhesus Monkeys, Oliver Hanisch

Loma Linda University Electronic Theses, Dissertations & Projects

The aim of this investigation was to characterize peri-implant tissue breakdown following ligature-induced plaque accumulation around osseointegrated implants in the rhesus monkey. Two hydroxyapatite-coated cylindrical implants were inserted bilaterally in the second premolar and first molar region of both mandible and maxilla in four non-human primates (Macaca mulatto). The implants were left submerged to osseointegrate for one year. Eight weeks after healing abutment connection, a two-month plaque control program was initiated. At the end of this period, clinical and radiographic recordings were carried out, and peri-implant subgingival microbial samples were obtained (baseline). Subsequently, cotton ligatures were placed around …

A Model Of Cytomegalovirus Association With The Development Of Heart Graft Atherosclerosis, Evan Skowronski

Loma Linda University Electronic Theses, Dissertations & Projects

The development of graft atherosclerosis in heart transplant recipients has been associated with the development of post-transplant cytomegalovirus infection. The mechanism of this involvement, however, remains unclear. I undertook a study to determine the role of cytomegalovirus in the development of graft atherosclerosis. First, a rapid method of detecting cytomegalovirus based on capillary polymerase chain reaction and gel electrophoresis was employed to determine the presence of cytomegalovirus in a wide variety of clinical samples. Detection of cytomegalovirus is a lengthy procedure under normal conditions, and timely detection of cytomegalovirus in transplant recipients may allow intervention early enough to block the …

Identification Of Variables Influencing Women's Breast Cancer Detection, Sherri Duckworth Kemp

Loma Linda University Electronic Theses, Dissertations & Projects

This study investigated the variables influencing women's breast cancer detection behavior. Using social learning theory as an organizing framework. factors influencing women's decisions to seek breast cancer detection and the respondent's personal demographics were examined for their contribution to explaining women's decisions to seek breast cancer detection.

A [convience] sample from a university medical center provided data for the study. Data were gathered with a voluntary questionnaire. A total of 25 employees from the medical center participated in the study during the winter quarter of 1994.

The findings of the study provide insight into some of the variables affecting women's …

The Rotations Of Maxillary Molars, Mandibular Molars, And Maxillary First Premolars In Acceptable Occlusions, G. Kristian Hansen

Loma Linda University Electronic Theses, Dissertations & Projects

The rotation of the maxillary molars is considered important in the orthodontic treatment of malocclusions. In this study a computer analysis program was developed to examine the rotations of maxillary molars, mandibular molars, and maxillary first premolars in casts of permanent dentitions with acceptable occlusions. Ninety three sets of untreated "acceptable occlusion" models from the collection of the Foundation for Orthodontic Research (FOR) were scanned on a flat bed scanner at 600 dots per inch (dpi). The images were analyzed using custom software on a computer. Measurements were made by relating maxillary first permanent molars to the midline, the archform, …