Dentistry Commons^™

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 …

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. …

Comparison Of Microleakage In Three Sealant Placement Protocols Vs. The Enamel Loc System, Audrey T. Sheu

Loma Linda University Electronic Theses, Dissertations & Projects

PURPOSE: To evaluate sealant microleakage using four different application techniques.

METHODS: The four application techniques evaluated were acid etch only, Adper L-Pop bonding, Optibond bonding, and Enamel Loc One-Step Sealant. Sixty-four extracted third molar teeth were assigned on one of four application techniques (n=16) and Clinpro sealants applied according to the manufacturer's instructions. The teeth were thermocycled for 500 cycles, dyed, and embedded in resin. The samples were then sectioned and evaluated for microleakage on the buccal and lingual surfaces. Statistical methods employed to analyze the data were the Kruskal-Willis rank test and the Mann-Whitney U test.

RESULTS: No significant …

The Effect Of Mtad On Eight Strains Of E. Faecalis In Contaminated Root Canals, Bradley M. Newberry

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this investigation was to determine the antimicrobial effect of Biopure MTAD (a mixture of a tetracycline isomer, an acid, and a detergent) as a final irrigant on eight strains of Enterococcus faecalis (E. faecalis) in contaminated root canals of extracted human teeth. In addition, the Minimum Inhibitory Concentration (MIC) and Minimum Lethal Concentration (MLC) of MTAD were also measured on the same strains of bacteria. Two-hundred and forty extracted human teeth were instrumented using 1.3% NaOCl followed by 17% EDTA to remove the smear layer. The teeth were randomly contaminated with one of eight strains of E. …

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 …

Histological Comparison Of White And Gray Mta In Repair Of Furcation Perforations, Miguel Elias Mego

Loma Linda University Electronic Theses, Dissertations & Projects

Mineral trioxide aggregate (MTA) has been shown to promote regeneration of the periodontal apparatus when used as a repair material in furcation perforations. Two variations of MTA (Gray and White) have been introduced to the dental market. The purpose of this study was to histologically compare the in vivo response to immediate furcation perforation repair using gray or white MTA in beagle dogs.

Under general anesthesia, non-surgical root canal therapy and furcal perforations were performed on sixteen mandibular premolars of eight 2-year old beagle dogs. The perforations were immediately repaired with either white (n=8) or gray (n=8) MTA. The animals …

The Effect Of Topical Fluorides On The Microleakage Of Sealants, N. Jared Nation

Loma Linda University Electronic Theses, Dissertations & Projects

Purpose: The purpose of this study was to evaluate the possible microleakage found in two groups of sealants; a group bonded with a dentin bonding agent (DBA), and a group bonded without a DBA after exposure to a variety of topical fluorides.

Materials and Methods: Extracted, human molars were placed into 8 groups. Half of the groups contained sealants that were bonded with a DBA and the other remaining groups of sealants were bonded without a DBA. There were two control groups, one that had sealants bonded with a DBA and the other had sealants bonded without a DBA, but …

Effect Of Anti-Tgfß1 And Pycnogenol® On Scar Formation In Rats, Pilseong Kim

Loma Linda University Electronic Theses, Dissertations & Projects

Wound healing is a complex biologic process that involves chemotaxis and division of cells, neovascularization, synthesis of extracellular matrix proteins, and remodeling of the repaired tissues. Of equal importance is the restoration of normal tissue structure and function without scar formation. The aim of this study was to find out the clinical effects of anti-TGFß1 and Pycnogenol® on scarless wound healing on rat skin.

An acute incision wound model was used with 20 healthy rats. Four incisions were made on each rat's skin and 4 different variables were applied by local infiltration. The four variables were anti-TGFß1, Pycnogenol®, PBS, and …

Effects Of Various Hemostatic Agents On Bone, David Daryl Roland

Loma Linda University Electronic Theses, Dissertations & Projects

Previous studies have evaluated the effects of various hemostatic agents on radicular tissues following apical surgery. The purpose of this study was to examine the early osseous responses to seven hemostatic agents under identical conditions in rabbits. Sixteen adult male New Zealand white rabbits were used for this study. Following anesthesia, utilizing a midline submandibular incision, standardized bony defects were prepared on the lateral-superior regions of the mandible. Test materials were placed using standardized volumes and exposure times. Bone wax, Surgicel, Capset, alginate, Cut-Trol, Hemogin-L, and silver nitrate were compared to control sites irrigated with saline. Test materials or controls …

Identification Of Hard Tissue Using Dentin Sialoprotein (Dsp) As A Marker, Wallis E. Andeline

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to identify the early hard tissue formed in experimental pulp exposures capped with calcium hydroxide, mineral trioxide aggregate (MTA) or bone morphogenetic protein-7 (BMP-7) using dentin sialoprotein (DSP) as a marker. The pulps of eighty-five maxillary first, second and third molar teeth from twenty male rats were experimentally exposed. The exposed pulps were capped with calcium hydroxide followed by restoration with amalgam (n = 20), with MTA alone as a pulp capping agent and final restoration (n = 20) or with BMP-7 followed by restoration with MTA (n = 20). Ten teeth with Class …

Microleakage Of Various Restorative Materials Used For Preventive Resin Restorations, Jenny Chung Lee

Loma Linda University Electronic Theses, Dissertations & Projects

Introduction: This research was designed to compare the microleakage of various restorative materials used for preventive resin restorations and two methods of cavity preparation. The purpose of this study was: (1) to compare microleakage of four different restorative materials using two different type of preparation methods (bur and air particle abrasion) and (2) whether the use of a pit and fissure sealant over the restoration decreases microleakage.

Methods: One hundred and twenty eight, permanent human molars were randomly divided into four groups and restored with four restorative materials. Each group had been randomly divided into two subgroups. The teeth in …

Hard Tissue Forming Potential Of Mta Compared To Common Root-End Filling Materials, Nooshin Noghreian

Loma Linda University Electronic Theses, Dissertations & Projects

An ideal characteristic of root-end filling materials used in endodontics is the ability to enhance hard tissue formation. Studies have shown that MTA has the potential to enhance hard tissue formation when placed in contact with periradicular tissues. The mechanisms involved in hard tissue formation of MTA and other root-end filling materials have not been completely elucidated. The purpose of this investigation was to study the mechanism of hard tissue formation of commonly used root-end filling materials and MTA by evaluating alkaline phosphatase (ALP) activity and cell layer protein. Extracts of materials tested in this experiment were added to the …

Periradicular Response Of Immunodeficient Rats To Mechanical Pulpal Exposure, James E. Stich

Loma Linda University Electronic Theses, Dissertations & Projects

Periradicular lesions develop as a result of the interaction between root canal irritants and the immune system. The purpose of this study was to investigate the periradicular response of immunodeficient rats to their oral flora. Twenty Sprague-Dawley rats received a total body irradiation dose of 750 cGy one week prior to the investigation. The pulps of the mandibular first molars of these animals and six nonirradiated rats were exposed mechanically with a ½ round bur and left open to the oral cavity. Additional irradiation (350 cGy) was administered bi-weekly to maintain immunosuppression. Periradicular specimens were obtained after two and four …

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, …

The Effect Of Root End Demineralization On Cementogenesis : A Long Term Investigation, Hamid R. Abedi

Loma Linda University Electronic Theses, Dissertations & Projects

Craig and Harrison¹² examined the effect of demineralization of resected root ends on wound healing following periradicular surgery. Based on its microscopic evaluations from 4-45 days, it was proposed that demineralization of resected root ends enhances cementogenesis. The purpose of this study was to investigate the longer term effects of demineralization on cementogenesis using Mineral Trioxide Aggregate (MTA) or amalgam as root end filling materials. After completion of root canal therapy and endodontic surgery on seventy-two roots of mandibular second, third and fourth premolars of six beagle dogs, 32/72 of the root ends at random were etched with 50% …

An Animal Model For Development Of Pulpal Inflammation, John W. Masters

Loma Linda University Electronic Theses, Dissertations & Projects

Several animal models have been proposed to develop pulpal inflammation. Procedures recommended in these models have many variables and have not produced consistent results. The purpose of this study was to create pulpal inflammation using the Nd:YAG laser.

Forty-five cuspids of 12-18 month old beagle dogs were lased at 5, 7.5, and 10 watts (W) for 20 seconds with a 600 micron contact probe. Five cuspids were not lased but were used as controls. Following laser application, the teeth were extracted at intervals of 3, 7, and 30 days. They were then fixed in 10% formalin, decalcified, sectioned, and stained …

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 …

The Effect Of Guidor™ And Hop-1 On Hard Tissue Healing : Following Periradicular Surgery In Cats, Hugh Maguire

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to evaluate the effects of the resorbable membrane Guidor™ and the osteogenic protein hOP-1 on hard tissue healing following periradicular surgery in cats.

Surgical endodontic therapy was performed on the maxillary canine teeth of twelve cats. After orthograde root canal therapy, flap reflection, osteotomy, resection of the root end, root end cavity preparation and the placement of a root end filling, eight of the surgical sites were treated with Guidor™ and eight with hOP-1. The remaining eight sites received no further treatment and served as controls.

The animals were sacrificed at twelve weeks following …

Bone Morphogenetic Proteins And Periodontal Repair, Michael B. Lee

Loma Linda University Electronic Theses, Dissertations & Projects

For over thirty years now, research has been carried out to isolate and purify bone morphogenetic protein (BMP), a substance which has been shown to induce heterotopic bone formation in various animal species. Recent advances in the fields of developmental biology, molecular biology and genetics, have shown that the BMPs not only are responsible for postfetal bone induction (including normal bone remodeling, healing and repair), but are also critical during embryogenesis - not only in regards to the skeletal system, but quite possibly in the morphogenesis and pattern formation of other tissues and organs as well.

Due to their bone …

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 …

Healing Potential Of Osteotomies Of The Nasal Sinus In The Dog, Roderick W. Tataryn

Loma Linda University Electronic Theses, Dissertations & Projects

Maxillary sinus osteotomy is sometimes indicated for transantral surgical approaches to palatal roots of maxillary molars. A search of the literature showed an absence of any report on the healing potential of such defects. The purpose of this study was to determine histologically the reparative process of the nasal sinus of dogs following small and large surgical antral perforations. After anesthetizing six beagle dogs, full thickness periosteal flaps were raised overlying the maxillary buccal cortical plates. A 5x5 mm diameter perforation was created with a trephine bur above the second maxillary premolar on one side of each animal. On the …

Development Of Periapical Lesions In Immunosuppressed Rats, Phillip A. Waterman Jr.

Loma Linda University Electronic Theses, Dissertations & Projects

The pathogenesis of periapical lesions is the interaction of the oral flora with the existing host defenses. The role of bacteria has been established in endodontic disease but the contribution of the host defenses in periapical lesion formation is less clear. The purpose of this study was to compare periapical lesion development in immunosuppressed rats with that in normal rats. Thirty-five, eight-week old Sprague-Dawley rats were equally divided into seven groups. Groups 1, 2, and 3 were given weekly injections of Cytoxan, an immunosuppressive agent. Groups 4, 5, and 6 received no immunosuppressive therapy. Group 7 served as a control, …

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 …

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 …

The Role Of T Cells In The Pathogenesis Of Periapical Lesions, John B. Wallstrom

Loma Linda University Electronic Theses, Dissertations & Projects

The pulps of mandibular molars of 15 athymic and 15 conventional rats were surgically exposed and left open to their oral flora. Each group was divided into 3 subgroups of 5 animals each. The rats were sacrificed after their pulps were exposed for 2, 4, or 8 weeks. After fixing, decalcifying, and embedding, the specimens were sectioned and stained with H and E. They were then examined under a microscopic grid and quantified by percentages of surface areas of bone, connective tissue, bone marrow, intrabony spaces, periapical lesions, and numbers of osteoclasts. This was done using a DataVoice computerized data …

The Effect Of An Anti-Osteoclastic Agent And A Collagen Sponge On Root Resorption Following Regenerative Periodontal Surgery In The Dog, Rudolf Hahn

Loma Linda University Electronic Theses, Dissertations & Projects

Previous studies indicate that root resorption is a frequent sequela to significant amounts of periodontal repair following experimental regenerative periodontal surgical procedures in animal models. To study if root resorption can be reduced or prevented, periodontal repair was evaluated in large horizontal circumferential defects in the dog in the absence of influence from the oral environment. Diphosphonate (Cl₂ MDP) applied topically to the root surfaces prior to wound closure as well as the use of a collagen sponge membrane (Helistat®) draped over the root surfaces and a control with no additional treatment after defect creation were the modalities employed. …

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

Loma Linda University Electronic Theses, Dissertations & Projects

[Abstract Not Included]

The Effects Of Certain Oral Bacteria On The In Vitro Growth Of Bacteroides Gingivalis, Steven G. Morrow

Loma Linda University Electronic Theses, Dissertations & Projects

The effect of nine gram positive and grain negative cocci and bacilli, which are indigenous to the oral cavity, on the in vitro growth of Bacteroides gingivalis was examined in this study. A pure culture of B. gingivalis is was obtained from the American Type Culture Collection. The nine oral test organisms were Streptococcus mitis, Streptococcus mutans, Streptococcus faecalis, Staphylococcus epidermidis, Staphylococcus aureus, Corynebacteriurn hofmanii, Lactobacillus acidophilus, Branhamella catarrhalis, and Escherichia coli. The effect on the growth of B. gingivalis of the nine test organisms was evaluated on a solid medium by use of …

The Effect Of Folic Acid Supplementation On Gingival Healing After Oral Hygiene Therapy, Marilyn J. Wankier

Loma Linda University Electronic Theses, Dissertations & Projects

To determine the effect of folic acid supplementation on gingival healing after oral hygiene therapy, eight teeth (#3, 4, 5, 6, 11, 12, 13, 14) of sixteen human subjects with moderate levels of gingival irritation were studied. Clinical parameters included measurement of gingival fluid, pocket depth, bleeding upon probing, and plaque. Serum and red blood cell folic acid levels were determined using radioimmunoassay (RIA). Based on clinical parameters and serum folate levels, two similarly matched groups were established. The teeth were scaled and polished. Brushing and flossing instructions were given.

After one week of oral hygiene therapy alone, the experimental …

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 …