Dental Materials Commons^™

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 …

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

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 …

A Pilot Study Comparing The Forces Applied : Using A Chin Cup And Three Types Of Protraction Headgear, Daniel Miles Beisiegel

Loma Linda University Electronic Theses, Dissertations & Projects

A pilot study comparing force distributions of a chin cup, the Great Lakes reverse pull headgear (RPHG), Ormco's adjustable dynamic RPHG, and Grummons RPHG was done. A skull from a 69 year old female which demonstrated a Class III malocclusion was used to perform the tests of force. Forces applied to and generated on the skull were measured using a water-filled balloon system. This method was tested and found to be reliable and accurate.

Repeated measurements of force were recorded for each of the areas of stress (forehead, cheeks, chin, and condyles, as well as the posterior and superior portions …

An In Vitro Quantitative Evaluation And Comparison Of A Custom And A Popular Stock Orthodontic Appliance, Richard Scott Anderw Schalo

Loma Linda University Electronic Theses, Dissertations & Projects

An in vitro performance evaluation and comparison of a patient individualized appliance (Elan, Ormco Corporation, Glendora, California) and a Roth prescription appliance ("A"- Company, San Diego, California) was made using the Ideal Tooth Relationship Index (ITRI).

The sample consisted of 19 duplicated sets of models for a total sample of 38. For each pair of models one set was bonded with an Elan appliance and a duplicated set was bonded with a Roth appliance. Bracket placement followed the manufacturers recommendations. The bracketed teeth from these models were sectioned out individually and the appliances allowed to fully express themselves on full …

Load Deformation Test Of Mini Twin Metal Brackets : A Comparative Study, Karl D. Peach

Loma Linda University Electronic Theses, Dissertations & Projects

The trend toward more esthetic brackets has led to smaller brackets being used by orthodontists. The purpose of this study was to determine the force required to deform these smaller brackets and calculate the stress in the metal by using a torsional wire bending force. Ten types of brackets were tested and the results analyzed to determine how bracket geometry, manufacturing method, or material selection affected the strength of brackets. Results showed a significant difference between manufacturing methods, material used, and bracket geometry. Brackets made of 17-4 PH SS and 303 SS withstood higher stress than 316 SS, and all …

An Evaluation Of Surface Enamel Damage Following The Debonding Of Ceramic Brackets : A Follow-Up Study, C. Steven Edney

Loma Linda University Electronic Theses, Dissertations & Projects

Surface enamel damage was evaluated after debonding ceramic brackets on forty-four bicuspid teeth. These teeth had been previously bonded with two different types of ceramic brackets. One of the brackets utilized a mechanical base for retention and the other bracket utilized a polycarbonate base for retention. The brackets were bonded to the respective teeth for a total of seven to ten days. After debonding, the teeth were extracted and evaluated with a scanning electron microscope. A metal bracket SEM scan was used for a control. The study concluded that: 1) all brackets alter the surface enamel, 2) metal brackets cause …

Retrofilling Materials : The Effects Of Two Setting Times On The Degree Of Dye Leakage Of Retrograde Filling Materials, Robert K. Higa

Loma Linda University Electronic Theses, Dissertations & Projects

Sealing of the root canal system is usually accomplished by the conservative endodontic approach. Cases where it is impossible to treat nonsurgically are usually treated surgically by an apicoectomy and retrofill. There is a lot of controversy in the literature over which retrofilling material is closest to ideal. Presently, the most popular materials seem to be Amalgam, Super EBA, and IRM. For this reason, these materials were chosen for this study to evaluate the leakage potential at two different time intervals to see if setting time of the material had any influence on the amount of leakage.

Seventy extracted single …

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 …

The Fracture Strength Of Ceramic Brackets : An Update And Comparison, Christian P. Manley

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to compare the fracture strength of ceramic brackets which are currently on the market with ceramic brackets tested in a previous study at Loma Linda. Fracture strengths of standard edgewise ceramic brackets vs. pre-torqued ceramic brackets and bicuspid ceramic brackets vs. central incisor ceramic brackets were also compared.

A total of 160 Polycrystalline brackets, 8 categories in groups if 20, were tested for fracture strength. Each bracket was tested using the same testing model that was used in the previous study at Loma Linda. The brackets were tested by torquing a wire within the …

The Impact Of Variations In Buccolingual Thickness Of Maxillary Anterior Dentition On First Order Arch Form Adjustments, Craig A. Andreiko

Loma Linda University Electronic Theses, Dissertations & Projects

Pre-adjusted bracket systems offer the clinician the convenience of working with both fewer in number and smaller magnitude adjustments in the archwire. The purpose of this study was to examine the normal variations in the thickness of the six maxillary anterior teeth and how this relates to anticipated first order bends in the archwire. A second purpose was to examine these same teeth for bilateral symmetry.

Thirty casts from the Loma Linda University completed treatment files were examined with respect to variations in the thicknesses of the crowns at the level of the archwire plane. From these, the mean difference …

Treatment Of Periodontal Furcation Defects, Michael Martin, Bernard Gantes

Loma Linda University Electronic Theses, Dissertations & Projects

[Note: Three parts in one.]

I. Review of the Literature and Description of a Regeneration Surgical Technique

This report provides an abbreviated review of the literature on treatment and prognosis of periodontal furcation lesions. In addition, it describes a surgical technique designed to accomplish bone regeneration in class II furcation defects, together with the rationale for the development of this procedure. Results of treatment of 30 defects with this technique are presented in a subsequent report (Gantes et al. 1987).

II. Bone Regeneration in Mandibular Class II Defects

A total of 30 mandibular, buccal class II furcation defects were treated …

A Comparison Of Liquid And Gel Etchants Determining Shear And Tensile Bond Strengths Of Four Orthodontic Adhesives, Gary M. Edgmon

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to compare liquid and gel etchants (37% phosphoric acid) by measuring tensile and shear bond strengths of four orthodontic adhesive systems.

Four orthodontic adhesives were tested on 287 extracted human teeth, 144 of which were etched with liquid and 143 with gel. The four adhesives tested were Concise-3M, Challenge-Ormco (new product), Unite-Unitek (no mix), and Fuji Glass-ionomer filling material or cement.

To eliminate the use of wire for bracket engagement during testing, two devices were designed and machined for direct attachment to the Instron testing machine: a rigid push rod for shear force and …

Histologic Host Response To Polyoxymethylene Prosthesis As A Temporomandibular Joint Condylar Replacement, Frederick R. Mathews

Loma Linda University Electronic Theses, Dissertations & Projects

Polyoxyinethylene (Delrin) is a polyacetyl homopolymer which has been used successfully in many orthopedic joint replacements. To determine histologic host response to Delrin as a temporomandibular joint condylar replacement condyles were removed from ten fully mature macaca fasicularis monkeys. The condyles were replaced with a total prosthetic Delrin condyle attached to a titanium mesh. Specimens obtained at one, two, and six months indicated total acceptance of the Delrin, remodeling of the glenoid fossa and formation of bone between the middle cranial fossa and the roof of the glenoid fossa. These findings would indicate Delrin is a viable option for condylar …

Analysis Of The Time-Dependent Force Loss Of Orthodontic Wires, David Jaekwan Jo

Loma Linda University Electronic Theses, Dissertations & Projects

In testing the force loss of five brands of orthodontic wire under a variety of stress modes, it was found that; 1) heat treatment reduced force loss in all the wires; 2) the amount of time-dependent force loss increased when the magnitude of force was raised.

A further indication was that a sharp bend on the tested wire did not affect force loss. Force applied to unwind a loop produced force losses from 180 to 350% above the loss that occurred when force was applied to wind a loop.

The force loss data collected during a 72-hour period was analyzed …

A Comparison Of Enamel Detachments After Debonding Between Unitek's "Dynalok" Bracket And A Foil-Mesh Bracket: A Scanning Electron Microscope Study, Robert E. Meister

Loma Linda University Electronic Theses, Dissertations & Projects

The intent of this paper was to: 1. Evaluate the mode of adhesive failure when debonding both flexible and rigid base orthodontic brackets. 2. Evaluate the bracket bases for enamel detachments. 3. Measure the enamel detachments.

After preforming shear test on flexible and rigid base orthodontic brackets mounted to extracted human teeth it was determined that failure occurred at the enamel/adhesive interface 30% of the time, at the bracket/adhesive interface 10% of the time and a combination of these 60% of the time for both groups.

Five brackets from each group were evaluated for enamel detachments using energy dispersive x-ray …

An Evaluation Of 17-4 Precipitation-Hardenable Stainless Steel Alloy For Use As An Orthodontic Wire, Martin G. Martz

Loma Linda University Electronic Theses, Dissertations & Projects

17-4 precipitation-hardenable stainless steel, a high strength alloy developed for aircraft applications, has been examined for possible use in orthodontics. The effects of solution treatment, various refrigeration treatments, and various aging treatments on standard tensile properties were measured. Comparisons were made with the tensile properties of 18-8 stainless steel and a Co-Cr alloy presently used in orthodontics.

Solution treatment was found to decrease ultimate strength by 37.8%, 0.2% yield strength by 45.9%, and (YS)/E ratio by 36.7%, while having almost no effect on elastic modulus or percentage elongation. Refrigeration treatments had statistically significant but small effects on tensile properties. Aging …

A Comparison Of Two Rapid Palatal Expansion Appliances And Their Effect On Palatal Cross-Sectional Area, William D. Scott

Loma Linda University Electronic Theses, Dissertations & Projects

Two rapid palatal expansion appliances, acrylic-free and acrylic-reinforced, were compared for their effect on the cross-sectional area of the palate. Two groups, twenty-five patients in each, were selected so that they would match as closely as possible with regards to age and sex distribution. The pre-treatment and post-treatment maxillary models were duplicated, and this duplicate model was then trimmed in a specific manner to allow the cross-sectional area between the first permanent molars to be compared. The results indicate that there is no difference, at the five percent level of significance, between these two appliances. It is concluded that the …

Force Loss In Retraction Springs At 37°C As Affected By Time, Roger Edward Clawson

Loma Linda University Electronic Theses, Dissertations & Projects

Closed helix retraction springs fabricated from .016 X .016 inch Blue Elgiloy, Permachrome Standard stain less steel, and Multiphase orthodontic wire were tested at 37°C in their heat and nonheat treated condition to determine force relaxation properties. Electronic equipment consisting of load cells, regulated power supply, and an automatic recording device were used to measure force changes which occurred in the wire samples over a seven day period. A constant temperature was maintained by an ethylene glycol and water circulator. A temperature probe and an electronic thermometer monitored the 37°C water bath surrounding the wire samples. The data was graphed …

A Comparative Study Of Tensile Properties In Five Orthodontic Wires, Charles B. Mcdermott

Loma Linda University Electronic Theses, Dissertations & Projects

The tensile properties of .017 x .025" stainless steel. Multiphase, Blue Elgiloy, beta titanium, and Nitinol were tested and compared. All wires were tested in the "as received" condition. Fifteen samples of each type of wire were tested in order to determine the (1) modulus of elasticity, (2) .2% yield strength, (3) ultimate tensile strength, (4) percentage elongation and (5) maximum elastic deflection.

The modulus of elasticity and .2% yield strength are the most important properties to orthodontists because of their influence on the wire's stiffness, strength and range. The ratio of yield strength/modulus of elasticity, termed maximum elastic deflection, …

Toxicity Of Root Canal Filling Materials On Hela Cells And Fibroblasts, Eldon P. Carman

Loma Linda University Electronic Theses, Dissertations & Projects

A study was undertaken to determine the concentration at which a sealer reaches a point of nontoxicity. An in vitro model utilizing HeLa cells and human fibroblasts was used to observe the effect of various concentrations of eight freshly mixed and eight set root canal sealers. Evaluation of toxicity was determined by cell survival which was measured by incorporation of ³H-thymidine into the nucleic acid components of each cell type used. Each dilution tested was allowed direct contact with the cells for 24 hours before toxicity evaluation. The results indicate that all sealers at concentrations presently used are cytotoxic …

An Ultra-Violet Light Microscopic Study Of The Hydroxylapatite Ceramic-Bone Interface Phenomena, Leonard W. Pierce

Loma Linda University Electronic Theses, Dissertations & Projects

Preparations used in this study were obtained from an investigation which had undertaken the following:

Durapatite, a hydroxylapatite ceramic was implanted in 24 mature Beagle dogs to study its maintenance effect on the alveolar bone of the mandible.

After dividing the dogs into two groups, a fresh socket and a healed socket group, the posterior teeth were removed and alveolectomies were performed. Eight ceramic implants were then placed in the right mandible of each animal in each group. The healed group received the implants five weeks after tooth removal and the fresh socket group received implants immediately after extraction.

The …

Methodology In Measurement Of Load Loss Or Gain In Orthodontic Wires : A Pilot Study, Merton S. Lacy

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this investigation was to develop methods and equipment to measure and record over any desired length of time the loss or gain in force of any material used in orthodontics that can produce a force upon an object. The material and the object being acted upon should not be disturbed while measuring that force.

Holding devices were designed and constructed in two basic forms. For intrusive and extrusive type forces, a load cell was fixed horizontally in such a position that an adjustable tube with a set screw to hold the wire could be rotated to cause …

Fatigue Properties Of Orthodontic Wire, Kirkland B. Reuer

Loma Linda University Electronic Theses, Dissertations & Projects

Fracture of orthodontic appliances can be a problem because of the time involved to replace and repair them. It has been shown that most failures have been a result of fatigue fracture, i.e., failure resulting from cyclic loading.

The purpose of this study was to determine what effect variation of the type of orthodontic wire and heat treatment had on fatigue resistance. A device was constructed to put a cyclic load on a piece of wire until fracture. Two types of cobalt-chromium alloy wire (Blue and Green Elgiloy from Rocky Mountain Orthodontics) and three types of stain less steel wire …

Effects Of Heat Treatment On The Mechanical Properties Of Chromium-Cobalt Alloy Wire, Robert L. Nations

Loma Linda University Electronic Theses, Dissertations & Projects

Since virtually all stages of orthodontic treatment involve forces obtained from deformed metallic materials, an understanding of properties of metals is an important part of orthodontics. The use of chromium-cobalt alloy for arch wires is relatively new to the field, and more needs to be known about its use in order to get the most from this product.

Many clinicians feel that advantages can be gained through a low temperature heat-treatment to change certain mechanical properties of the material. A tensile test was chosen in the attempt to learn more about this alloy in the untreated form as well as …

A Clinical Method For Predicting Orthodontic Band Sizes, Robert P. Mohr

Loma Linda University Electronic Theses, Dissertations & Projects

A correlation was established among the orthodontic band sizes in a given individual. The original sample contained 258 data sets (Unitek Corp. band sizes from first molar through the first molar in both arches) which were computer analyzed. The maxillary right central incisor band size was selected as the "predictor size" for a band size prediction table developed from this study.

An additional 56 data sets were tabulated and became the test sample to test the accuracy of the band size prediction table. Band sizes of the test sample were predicted within ±1 band size 66% of the time and …

Tensile Properties Of Stainless Steel Orthodontic Wire, Elbert E. Jackson

Loma Linda University Electronic Theses, Dissertations & Projects

Ten types of .020 inch stainless steel wire were compared using a tensile test. The wires were tested in the as-received condition and after heat treatment at 750°F for eleven minutes. The data were then analyzed statistically using the general linear hypothesis.

In the as-received condition each of four mechanical properties--elastic modulus, 0.2 per cent yield strength, tensile strength, and percent elongation--was found to vary significantly from one type to another.

When subjected to heat treatment, the elastic modulus proved to be the most stable of the four properties, changing only slightly in three cases. There was no significant change …

Determination Of Lead Content In Apical Tissue Following Root Canal Obturation With Sargenti's Formula, G. Merle Hickok

Loma Linda University Electronic Theses, Dissertations & Projects

Four Stump-tail monkeys were used to help determine if the lead in Sargenti's formula diffuses out into the apical tissue while confined entirely within the root canal. In each animal two teeth were filled with Sargenti's formula 1-2 millimeters short of the radiographic apex, and two teeth were filled with gutta percha and Proco-Sol sealer for controls, making a total sample size of sixteen. The time ranged from 48 hours to 120 days. Lead analysis using the spectrophotometric method showed a higher lead content in the teeth filled with Sargenti's formula than with the gutta percha controls.

An Evaluation Of A Precipitation Hardened Stainless Steel Alloy As An Alternate To Chrome Cobalt Alloys For Orthodontic Purposes, Joseph M. Caruso

Loma Linda University Electronic Theses, Dissertations & Projects

The intent of this paper was to evaluate a precipitation hardenable stainless steel (Alloy I) as an alternate to chromium cobalt alloys (Alloy II) for orthodontic purposes.

After evaluating several heat treatments of alloy I it was determined that solution treatment produced a wire that was soft initially and had similar properties found with alloy II. After solution treatment of alloy I a 330 gram load was required to deform the wire 1.0 mm which proved to be similar to the 295 gram force required for alloy II for the same deformation and only an 11% increase in resistance of …