Dental Materials Commons^™

Correlation Of Tooth Length Measurements Made On Cbct And 3t Mr Images, Andrew Scott Taylor

Loma Linda University Electronic Theses, Dissertations & Projects

Objective. This study compared tooth length measurements made on cone beam computed tomography (CBCT) scans and 3-Tesla (3T) magnetic resonance (MR) scans performed with and without an alginate bite registration surrounding the crowns of the teeth. Materials and Methods. One CBCT scan, one MR scan with alginate bite registration, and one MR scan without bite registration were performed on 12 subjects. The alginate bite registration was used to provide a proton-rich material to surround proton-poor teeth in an attempt to improve visualization of teeth. DICOM formatted images from each of the three scans for each subject were oriented in all …

Influence Of Low Temperature Degradation On Microstructural Integrity Of Zirconia Dental Implants, Mona Monzavi Rahimi

Loma Linda University Electronic Theses, Dissertations & Projects

Zirconia dental implants have become more popular in the field of implant dentistry. However, concerns have been raised regarding low temperature degradation and its influence on phase stability and micro-structural integrity in terms of increased micro-crack formation. In the case of dental implants, this could possibly result in delamination and interference with bone to implant contact and eventually lead to loss of integration and failure. Nevertheless, no study has reported the effects on commercially available Zirconia dental implants. The primary aims of this study was to determine if there is a correlation between ageing duration and 1) depth of tetragonal-monoclinic …

Effects Of Microwave Irradiation On The Dimensional Stability Of Complete Denture Bases, Miguel Pappaterra

Loma Linda University Electronic Theses, Dissertations & Projects

Introduction: Maintenance for complete dentures is a role that must be undertaken by the patient. It has been determined that two minutes of microwave irradiation at 650 Watts provides denture disinfection, and three minutes provide sterilization32,34. There is insufficient data on how this practice affects the long term dimensional stability of commonly used complete denture bases in the United States. Purpose: The purpose of this study was to perform an in-vitro investigation, testing and comparing the effects of microwave irradiation on the dimensional stability of three types of complete denture bases. Materials and Methods: An edentulous master cast with reference …

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 …

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 …

The Effect Of Auxiliary Preparation Elements On The Resistance Form Of Complete Metal Crowns, Mostafa Nazari

Loma Linda University Electronic Theses, Dissertations & Projects

This study measured the resistance to dislodgment of complete metal crowns when they were fabricated for tooth preparations lacking resistance form. These preparations were modified with four different auxiliary preparation features.

An Ivorine mandibular first molar was prepared on a milling machine with the following characteristics: 20 degrees of total occlusal convergence (TOC), 360 degrees shoulder finish line of 1.0 mm width, and axial wall of reduced height offering no geometric resistance form. The following tooth preparation modifications were studied:

1. Two proximal grooves (two lingually positioned grooves, one on the mesial and one on the distal surface) (design B) (Figures …

Effect Of Auxiliary Preparation Elements On Resistance Form Of Complete Crowns, Manuel H. Guevara

Loma Linda University Electronic Theses, Dissertations & Projects

This study compared the effectiveness of six different auxiliary preparation elements on the resistance to lateral dislodgment of complete crown preparation lacking resistance form.

An ivorine mandibular first molar was prepared with the following characteristics: 20° TOC, 360° shoulder finish line of 1.0 mm width and axial wall of reduced height offering no geometric resistance form (Group A: control). Preparation modifications were Group B: MD grooves, Group C: BL groves (sic), Group D: MDBL grooves, Group E: MD small boxes, Group F: MD large boxes and Group G: 8° TOC at the cervical 2 mm of the axial walls. Ten …

Immediate Loading Of Unsplinted Implants In The Anterior Mandible For Overdentures, Phillip Roe

Loma Linda University Electronic Theses, Dissertations & Projects

In this one-year prospective study, eight completely edentulous patients were selected from the Loma Linda University School of Dentistry (LLUSD) patient population to participate. There were five male and three female patients, between the ages of 58 and 82 (mean age of 69.1 years). All participants received new maxillary and mandibular complete dentures prior to implant placement. Two 4.0 mm x 13 mm threaded implants with a fluoride-modified, micro-roughened, titanium surface were placed mesial to each mandibular canine position. Locator abutments were connected and torqued to 25 Ncm and primary closure was achieved with a nonresorbable suture material. The Locator …

Short-Term Clinical Evaluation Of Nobelreplace® Tapered Groovy Implant, Manouchehr Pouresmail

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this clinical investigation was to make comparisons and to achieve estimates of the short-term implant success, marginal bone resorption, and soft tissue responses around the immediately loaded NobelReplace® Tapered groovy implant (with groove on a rough collar portion) as compared to an implant without a groove on the collar (Replace®Select Tapered). This was a randomized controlled and prospective investigation in which subjects were consecutively included according to strict inclusion/exclusion criteria. Single stage procedure was used with immediate function. Seventeen subjects were recruited, and were randomly divided in two groups. Each group was received the predetermined type of …

An In-Vitro Investigation Of The Physical Properties Of Alginate Alternatives, Rishi Dinesh Patel

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to evaluate the detail reproduction, gypsum compatibility and linear dimensional change of three recently introduced irreversible hydrocolloid (alginate) alternatives. The materials that were tested are Position Penta Quick® (3M ESPE™), Silgimix® (Sultan Dental) and Alginot® (Kerr™). These materials were tested in accordance with ANSI/ADA Specification No. 18 for Alginate Impression Materials and No. 19 for Dental Elastomeric Impression materials. The irreversible hydrocolloid impression material Jeltrate Plus antimicrobial® (Dentsply Caulk™) served as the control.

MATERIALS AND METHODS: The ADA specification die was used to undertake the testing of the new materials. The parameters of detail …

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 …

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 …

Immediate Provisionalization Of Single 3.0 Mm Diameter Implant In Maxillary And Mandibular Anterior Region, Kotaro Oyama

Loma Linda University Electronic Theses, Dissertations & Projects

Immediate provisionalization of single implants with standard (3.75 - 4.5 mm) and wide diameter (> 4.5 mm) has been well documented. When the space is limited, small diameter implants (3.0 mm) must be used. Although high success rates have been reported, they were limited to healed site and were placed as staged procedures. The purpose of this prospective study was to evaluate the success rate and peri-implant tissue response of small diameter (3.0 mm) implants undergoing immediate provisionalization in the esthetic area.

Eleven patients who had missing maxillary lateral incisor(s) and/or mandibular incisor(s) participated in this study. Thirteen 3.0 mm …

Effect Of Gutta Percha On The Retention Of A Post Using Different Cements, Saeda H. Basta

Loma Linda University Electronic Theses, Dissertations & Projects

This study evaluated the effect of residual gutta percha on the retention strength of prefabricated post cemented with four different cements. Forty intact mandibular single canal canines or premolars were selected for standardized size and quality, endodontically treated, and decoronated to the cementoenamel junction. A post space was prepared to accommodate Para post XP size 4 (Coltene, Whaledent Inc., Cuy Falls, Ohio) to a depth of 8 mm. The Obtura heated gutta percha system was used to inject a very thin line of gutta percha along one lateral wall to the depth of the future post. Forty obturated teeth were …

Veneer Failure On Preveneered Primary Posterior Stainless Steel Crowns, Matthew H. Gustafsson

Loma Linda University Electronic Theses, Dissertations & Projects

PURPOSE: The purpose of this study was to determine the amount of force required to fracture or dislodge the veneered facings from three veneered lower primary molar stainless steel crowns (SSC) and to characterize the veneer failures.

METHODS: The following veneered crowns were used in this study: NuSmile crowns, Kinder Krowns, and EC crowns. Twenty lower right primary first molar crowns were used from each manufacturer, for a total of 60 crowns. All crowns were cemented with glass ionomer cement to a custom fabricated die. Twenty-four hours following cementation, each die with the cemented crown was placed into a custom …

Comparison Of Laser And Phosphoric Acid Etching On Sealant Shear Bond Strength, Seth David Latimer

Loma Linda University Electronic Theses, Dissertations & Projects

PURPOSE: To compare the effect of traditional phosphoric acid etching with Er,Cr:YSGG laser enamel etching on the shear bond strength of sealant material.

METHODS: Extracted healthy third molars were mounted in acrylic exposing the flattest surface available. Three groups of twenty teeth were used to evaluate traditional acid etching with 37% phosphoric acid as a control group as well as two different laser settings. The sealant material was attached using specialized jigs and then subjected to shear bond strength testing utilizing the ultradent method (MTS machine). Statistical methods employed were the Kruskal-Wallis rank test and the Mann-Whitney U test.

RESULTS: …

Detoxification Of Lipopolysaccharide By Endodontic Sealers, Dominic Côté

Loma Linda University Electronic Theses, Dissertations & Projects

Bacterial lipopolysaccharide (LPS) has been implicated in the pathogenesis of pulpal and periapical diseases. Several studies have evaluated the ability of various medicaments and irrigants used during root canal therapy to chemically detoxify LPS. The purpose of this study was to evaluate the ability of some endodontic sealers to detoxify LPS. This investigation compared the quantities of TNF-α released by human monocytes exposed to LPS or LPS pre-treated with sealers. The sealers tested were: Pulp Canal Sealer EWT (PCS), AH Plus (AH), and Sealapex (SA). Ca(OH)₂ and water (H2O) were respectively used as the positive and negative control materials. …

Resorbable Barrier Effect In Sinus Graft Using Anorganic Bone, Kyung-Soo Choi

Loma Linda University Electronic Theses, Dissertations & Projects

The effect of a resorbable membrane on new bone formation in human maxillary sinus augmentation using anorganic bovine material is unclear at the present time. As a pilot study, six patients who required bilateral maxillary sinus augmentations for endoessous dental implant treatment were grafted with anorganic bovine bone material. All six patients had a resorbable collagen membrane placed over the graft material on only one side for the sinus augmentation. At the time of implant placement, a minimum of 8 months following sinus graft healing, a biopsy was made of each side to permit histomorphometric analysis.

Similar amounts of new …

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 …

The Effect Of Calcium Hydroxide Pastes On Root Dentin Fracture Resistance, Kurt W. Sturz

Loma Linda University Electronic Theses, Dissertations & Projects

Calcium hydroxide is a common intracanal medicament used in the treatment of immature teeth that have been subjected to trauma or decay prior to root canal therapy. The effect of calcium hydroxide on immature root dentin is important. One area of concern is the effect that calcium hydroxide has on the fracture resistance of an immature tooth. It is the aim of this study to compare the effect of four different commercially available calcium hydroxide pastes on the fracture resistance of bovine teeth. Seventy-five freshly extracted, intact bovine incisors were prepared according to a modified Haapasalo and Orstavik technique. Each …

Bone Morphogenic Protein Induced Repair Of The Premaxillary Cleft, Rick J. Rawson

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study is to evaluate the bony augmentation of premaxillary clefts in humans using recombinant bone morphogenic protein (rhBMP-2) in a collagen sponge carrier. 12 patients with unilateral cleft alveolar ridges were evaluated pre- and 4 months postoperatively. 10 patients were repaired with rhBMP-2 while two others were grafted with anterior iliac crest particulate marrow cancellous bone (PMCB). Computed tomographic studies were used to evaluate preoperative alveolar cleft volumes, postoperative bone bridge volumes, and pre/post operative volume ratios.

A pre/post operative volume ratio for patients repaired with rhBMP-2 ranged from 24.1% to 90.6% with a mean of …

Mineralized Bone Allograft In Maxillary Sinuses Histology And Histomorphometry, Sammy Stefan Noumbissi

Loma Linda University Electronic Theses, Dissertations & Projects

Background: Demineralized freeze-dried bone allografts (DFDBA) and deproteinized bovine bone xenografts (DMBBX) have been used for sinus augmentation for many years with varying results, but very little has been reported on the clinical efficacy or the histological analysis of mineralized solvent dehydrated bone allografts (MSDBA) as sinus graft materials. This study histologically and histomorphometrically evaluated an MSDBA material called PUROS to augment atrophic human maxillary sinuses.

Materials & Methods: Seven partially and completely edentulous patients requiring unilateral (n=4) or bilateral (n=3) sinus grafts prior to implant placement were selected for this study. Test grafts consisted of MSDBA, and control …

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 …

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, …

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 …

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

Loma Linda University Electronic Theses, Dissertations & Projects

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

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 …

Resonance Frequency Analysis As A Determinant Of Implant Initial Stability, Negar Tabandeh

Loma Linda University Electronic Theses, Dissertations & Projects

Introduction: The clinicians' decision regarding immediate loading is largely determined by the assessment of initial stability of the dental implant. Computed tomographic assessment of recipient site bone quality, insertion resistance torque and post-insertion resonance frequency are currently the only objective methods of measurement establishing initial stability.

Purpose: A study was designed to measure resonance frequency of root form dental implants placed in cadaver jaws. The resonance frequency values were compared to previous subjective and objective data reported in prior studies in the series.

Materials and Methods: Resonance frequency measurements were secured using the Osstell ™ mentor unit on 4.0 X …

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 …