Dental Materials Commons^™

The Management Of Aerosols With Airpolishing Delivery Systems, Caren M. Barnes

College of Dentistry: Faculty Publications

In summary. aerosol production is inherent with airpolishers. as well as other dental equipment such as handpieces, ultrasonic scalers, and air/water syringes. By practicing prudent infection control techniques and utilizing proper operating techniques, the clinician can continue to enjoy the time-efficient and efficacious benefits of airpolishers, while ensuring a maximum protection from aerosols for the patient and the operator.

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 …

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 …

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, …

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 …

The Development Of A New Appliance For The Third Stage Of Begg Treatment, Ronald C. Parker

Loma Linda University Electronic Theses, Dissertations & Projects

The third stage of Begg treatment can pose difficulties to the orthodontist. Some of the undesirable developments encountered are anchorage loss, unintentional tooth tipping, extrusion, intrusion, palatal and mandibular rotation, muscular strain and profile deficiency or procumbency. In the interest of eliminating or minimizing these developments a new appliance was developed for use during the third stage of treatment.

Simply described, the appliance consisted of a rigid vestibular arch that provided anchorage for flexible extensions to each tooth. Extraoral force was directed to the maxillary rigid arch to counter anterior root torquing forces.

Anchorage control, maxillary incisor torquing efficiency and …

Endodontic Sealing Properties Of Cavit, Chloro-Rosin Gutta Percha, N2, And Silver Cones Using Radioisotopes, Frank H. Beal

Loma Linda University Electronic Theses, Dissertations & Projects

The main purpose of this investigation was to test the endodontic sealing abilities of silver cones, N2, warm gutta percha, chemically softened gutta percha, laterally condensed gutta percha and Cavit under carefully controlled conditions. Evaluations were done by radiographic, macroscopic, microscopic, and autoradiographic examinations.

The four points which must be considered when evaluating the efficacy of sealing root canal systems, in vivo, were presented and discussed.

Cavit as a total endodontic filling material was presented, investigated and discussed.

An improvement of the chloro-rosin - gutta percha diffusion technique was presented.

The concept of surface as well as marginal leakage was …

A Clinical Evaluation Of A Technique Utilizing Plastic Modules For Cuspid And Incisor Retraction, Dwane I. Johnston

Loma Linda University Electronic Theses, Dissertations & Projects

In a clinical study, polyurethane-type plastic modules were evaluated for use in retracting cuspids and incisors in Class I extraction cases.

Seven patients were selected to be treated with a technique utilizing these plastic modules. All cases were in Class I molar relationship and were either bimaxillary, protrusive or had tooth-size, arch-length discrepancies.

Evaluation was based on rate of cuspid and incisor retraction and the control of molar anchorage during the retraction phase.

At four-week intervals data were collected on space closure. At the same time, such subjective data as amount and duration of pain, difficulty of appliance adjustment and …

Correlation Of The Actual Position Of The Root Canal Filling In Human Teeth To Its Apparent Location On The Radiograph, Dominic J. Niccoli

Loma Linda University Electronic Theses, Dissertations & Projects

Human teeth mounted in individual plaster blocks were studied to determine the actual location of the root canal filling when it appears to be exactly at the radiographic apex. The original sample consisted of 109 teeth treated during endodontic technique class by junior dental students at Loma Linda University. In the most ideal manner possible, these teeth were radiographed on a flat surface with the x-ray tube perpendicular to the film and blocked tooth.

Five dentists examined the radiographs, and each one independently listed the canals he judged filled exactly to the radiographic apex. The investigator sorted out the choices …

Accuracy Of The Indirect Method Evaluated By Mercury Micromeasurement, Estol C. Pruett

Loma Linda University Electronic Theses, Dissertations & Projects

Although the indirect method for preparing dental castings has been in use for over forty-five years, very little information has appeared in dental literature relative to its accuracy. The development of a precise and quantitative method for determining the adaptation of wax patterns or castings was necessary before such an evaluation could be considered valid. It was felt the Mercury Micromeasurement test, devised in 1958 by Hollenback, should meet these requirements. A description of the test had been published. However, at the time the project was begun, no data had appeared in the literature.

In order to establish a standard …