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Biomedical subjects

L J Oesterle

Publications and source records attributed to L J Oesterle.

At least 19 recordsLinked to original sources
PubMed2001

Bracket bond strength with transillumination of a light-activated orthodontic adhesive.

The literature describes transillumination as a means of curing orthodontic light-cured composite adhesive. The literature also recommends a 2 to 3 times increase in light exposure time when light curing using transillumination. The purpose of this study was to determine the transmittance of the curing light through human enamel and the effect of transillumination on the bond strength of orthodontic brackets. One hundred extracted human maxillary incisors were used in this study. Brackets with orthodontic composite adhesive were placed on the labial surface of the incisors and light cured from either the labial or the lingual (transillumination). The control sample was cured from the labial for a total of 40 seconds of light exposure. Experimental samples were cured from the lingual (transillumination) for 20, 30, 40, or 50 seconds. The shear-peel bond strengths were tested at 30 minutes and 24 hours after light application. The results of this study demonstrated no statistically significant difference between 40 seconds of labial curing and most of the lingually cured groups. The only experimental group that differed statistically from the control group was the 40-second lingual cure group tested at 30 minutes after light application. Actual bond strengths, however, were lower for all experimental samples. The samples tested at 24 hours that received 50 seconds of transillumination were nearly the same as the control values. This study demonstrated that transillumination of maxillary incisors is an acceptable method of curing orthodontic adhesive, particularly if the exposure time is increased from 40 to 50 seconds.

Analysis of Variance↗
PubMed2001

Rapid curing of bonding composite with a xenon plasma arc light.

The use of light-cured orthodontic adhesives is an increasingly popular method for the bonding of orthodontic brackets. However, one of the disadvantages of light-cured adhesives is their long curing times. The xenon plasma arc curing light is purported to dramatically reduce the required curing time. The purpose of this study was to test the efficiency of a xenon plasma arc light versus a conventional tungsten-quartz halogen light in producing effective bond strengths for orthodontic brackets. Standardized brackets were bonded to bovine enamel with 3 different orthodontic bonding materials. The bonding materials were exposed to the tungsten-quartz halogen light for 40 seconds and to the xenon light for 3, 6, and 9 seconds. Bond strength was tested 30 minutes and 24 hours after light-curing. The results showed that bond strength with the application of the xenon light was greater with longer exposures. There were no statistically significant differences between the bond strengths of the brackets exposed to the tungsten-quartz halogen light for 40 seconds and those exposed to the xenon light for 3, 6, or 9 seconds. However, xenon light exposures of 6 or 9 seconds were required to create bond strengths equal to those produced by the tungsten-quartz halogen light. The xenon light produced equivalent bond strengths at very short light exposures.

Analysis of Variance↗
PubMed2001

Enhancing wire-composite bond strength of bonded retainers with wire surface treatment.

Bonded orthodontic retainers with wires embedded in composite resin are commonly used for orthodontic retention. The purpose of this study was to test, in vitro, various wire surface treatments to determine the optimal method of enhancing the wire-composite bond strength. Coaxial wires and stainless steel wires with different surface treatments were bonded to bovine enamel and then pulled along their long axes with an Instron universal testing machine. Wire surface treatments included placing a right-angle bend in the wire, microetching the wire, and treating the wire with adhesion promoters; combinations of treatments were also examined. The results demonstrated a 24-fold increase in the wire-composite bond strength of wire that was microetched (sandblasted), compared with that of untreated straight wire. The difference between the amount of force required to break the bond produced by microetching alone (246.1 +/- 46.0 MPa) and that required for the bonds produced by the retentive bend (87.8 +/- 16.3 MPa), the adhesion promoters (silane, 11.0 +/- 3.1 MPa; Metal Primer, 28.5 +/- 15.8 MPa), or for any combination of surface treatments, was statistically significant. Microetching a stainless steel wire produced a higher wire-composite bond strength than that obtained from a coaxial wire (113.5 +/- 27.5 MPa). The results of this study indicate that microetching or sandblasting a stainless steel wire significantly increases the strength of the wire-composite bond.

Animals↗
PubMed1999

Maxillary midline diastemas: a look at the causes.

BACKGROUND: Maxillary midline diastemas are a common esthetic problem that dentists must treat. Many innovative therapies have been used, varying from restorative procedures to surgery (frenectomies) and orthodontics. At times, these procedures have been performed by the dentist without full appreciation of the factors contributing to the diastemas. CASE DESCRIPTION: Before the practitioner can determine the optimal treatment, he or she must consider the contributing factors. These include normal growth and development, tooth-size discrepancies, excessive incisor vertical overlap of different causes, mesiodistal and labiolingual incisor angulation, generalized spacing and pathological conditions. A carefully developed differential diagnosis allows the practitioner to choose the most effective orthodontic and/or restorative treatment. CLINICAL IMPLICATIONS: The differential diagnosis leads to a treatment approach that most effectively addresses the patient's problem. By treating the cause of the diastema, rather than just the space, the dentist enhances both the patient's dental function and appearance.

Adolescent↗
PubMed1999

Uprighting molars without extrusion.

BACKGROUND: Orthodontic molar uprighting often results in extrusion of the molar, which is not always beneficial. The authors present a strategy for accomplishing molar uprighting without extrusion. DESCRIPTION OF THE PROCEDURE: The authors review and compare the benefits of molar uprighting with and without extrusion. The helical uprighting spring is probably the most popular appliance used for molar uprighting. It exerts an extrusive force on the molar during uprighting. The authors explain why this appliance produces an extrusive force and present a strategy to modify the appliance so that it can be used to upright without extrusion. CLINICAL IMPLICATIONS: The information presented in this article should help the dental practitioner select a suitable appliance, understand how it works and use it appropriately so that molar uprighting can be achieved without extrusion of the molar.

Dental Stress Analysis↗
PubMed1998

The use of bovine enamel in bonding studies.

Bovine enamel is commonly used in enamel bonding studies, therefore, a familiarity with some aspects of bovine enamel bonding are important in order to evaluate the studies. Bovine enamel has the advantages of easy attainability and similar microstructure to human enamel. In this study the strength of the enamel bond using an orthodontic adhesive was compared between deciduous bovine, permanent bovine, and human enamel, as well as, the effect on bond strength of multiple rebonding to bovine enamel. This study found that the bond strength to bovine enamel was 21% to 44% weaker than to human enamel, and the bond strength to deciduous bovine enamel was significantly greater than to permanent bovine enamel. Either all deciduous or all permanent bovine incisors should be used, or permanent and deciduous bovine incisors evenly distributed in sample groups. Bovine enamel was rebonded five times without significantly affecting bond strength, thus, bovine enamel can be reused in bonding studies without significantly affecting the results.

Analysis of Variance↗
PubMed1998

Orthodontic competency in predoctoral education in American dental schools.

Predoctoral orthodontic education is evolving in the United States to reflect the move towards competency-based education. This trend focuses on teaching to competency in an area or procedure. In orthodontics, this creates a dilemma for the educator in determining what orthodontic competency actually is and how to achieve it. A survey of United States orthodontic departments was conducted to aid in examining the change toward competency-based education in predoctoral clinical orthodontics. The results demonstrated a large amount of diversity regarding both the definition and the use of competencies. The most recent US accreditation standards and guidelines are moving away from specific treatment techniques and more towards management and recognition of malocclusions for the recently-graduated general dentist.

Clinical Competence↗
PubMed1998

Implant use in growing patients. Treatment planning concerns.

The dynamic relationship of dental and craniofacial development to the use of dental implants in a growing patient must be understood before this treatment is initiated. This article describes the three dimensions of maxillary, mandibular, and skeletal growth and their relationship to the placement of dental implants. Recommendations are made for the use of dental implants in the growing individual predicated on the above parameters of growth and development.

Bone Development↗
PubMed1997

Effective orthodontics: achieving objectives, avoiding misadventures.

The authors outline four principles that should be considered when planning orthodontic tooth movement. They suggest that dentists have clear treatment objectives, know the force requirements to achieve those objectives, choose the best equipment to provide the needed forces and prevent unwanted tooth movement during treatment. To illustrate use of these principles, the authors refer to a sample treatment scenario. They also provide a mnemonic device to help dentists recall these principles.

Dental Stress Analysis↗
PubMed1994

Cephalometric values for adult Mexican-Americans.

Cephalometric studies of adult Mexican-Americans are incomplete. The purpose of this study was to evaluate whether significant cephalometric differences exist between adult Mexican-American, black American, and white patients. Lateral cephalometric radiographs were taken of 48 Mexican-American adults (23 men, 25 women). All subjects met the following criteria: parents, grandparents, or great-grandparents were born in Mexico; 18 to 50 years of age; Class I occlusion with minor or no crowding; good facial balance; no significant medical history or history of facial trauma; no previous orthodontic treatment or maxillofacial surgery. Twenty-five cephalometric measurements were analyzed. Significant racial and sexual differences were found in the following areas: skeletal measurement (SNA, ANB, PO-N perpendicular, Co-A, Co-Gn, ANS-Me, MP-FH, MP-SN); dental measurement (U1-A perpendicular, L1-APo, U1-L1, IMPA); soft tissue measurement (NLA, FCA, UFH (pu), ULL). Orthodontists and oral surgeons will find the cephalometric values of help in the diagnosis and treatment planning of potential orthognathic surgery patients.

Adolescent↗
PubMed1994

Ceramic bracket bonding: a comparison of shear, tensile, and torsional bond strengths of ceramic brackets.

The purpose of this study was to evaluate whether shear, tensile, or torsional forces were best suited for debonding ceramic brackets. Four commercially available ceramic brackets were evaluated. The brackets included both polycrystalline and monocrystalline types with either chemical or mechanical retention in the bracket bases. The ceramic brackets were bonded to one hundred and twenty bovine teeth, using Concise. The brackets were stressed until bond or bracket failure occurred with either shear, tensile, or torsional forces on the Instron machine. The maximum bond strength and the site of bond failure was recorded. Starfire TMB brackets fractured 30% of the time during shear debonding, whereas, Quasar 1000, Lumina, and Transcend 2000 brackets exhibited no bracket fractures. The shear bond strengths of Quasar 1000 brackets were significantly higher than Starfire TMB brackets. Starfire TMB was the only bracket type that exhibited no bracket fractures with tensile force. Tensile bond strengths were not significantly different between the four bracket types. In torsion, Lumina was the only bracket type that did not exhibit any bracket failures. Shear and tensile bond strengths of chemically retained brackets were not significantly different than mechanically retained brackets. Torsional bond strength of chemically retained brackets was significantly higher than mechanically retained brackets. The results suggest Quasar 1000, Lumina, and Transcend 2000 are best removed with shear or tensile forces. Starfire TMB is best removed with tensile forces.

Animals↗
PubMed1993

Maxillary implants and the growing patient.

Maxillary skeletal and dental growth results in dramatic changes in all three dimensions during active growth. Experimental evidence and the behavior of ankylosed teeth suggest that an osseointegrated object remains stationary in the bone surrounding it and does not move or adapt to bone remodeling. Growth changes may result in the burying or loss of implants depending on the placement site. Hence, implants placed in the early mixed dentition have a poor prognosis of continued usefulness through puberty. When placed early, implants may disturb growth or have to be replaced. Implants placed during late puberty or early adulthood have the best change for long-term usefulness.

Adolescent↗
PubMed1991

Raising the root. A look at orthodontic extrusion.

A simple technique using bonded wires to establish anchorage and an attachment to a tooth requires a minimum of special materials or advanced skills in orthodontics. The bonded wire stabilizes the anchor unit and avoids any adverse tooth movement.

Humans↗
PubMed1988

Individuality of human palatal rugae.

Investigators have implied that palatal rugae are unique to each individual. However, these researchers have disagreed as to whether or not legal identification could be based solely on palatal rugae. Previous studies used poor duplicating materials and may not have considered the effects of growth, extractions, palatal expansion, or some combination of these. The inadvertent use of other features of the cast, such as teeth, edentulous ridge morphology, muscle attachments, vestibular depth, or some combination of these, to aid in the identification, may have influenced their results. The purpose of this investigation was to determine if palatal rugae can be relied upon for identification. Twenty-five orthodontic cases were selected with pre- and post-treatment casts; orthodontic treatment had taken eighteen to sixty months. One hundred casts were randomly selected as variables. All casts were trimmed so that all areas except for the rugae area of the hard palate were removed. The twenty-five post-orthodontic casts were dispersed within 100 randomly selected casts. Nine investigators were given the twenty-five pre-orthodontic casts and asked to compare them to the other one hundred and twenty-five casts for possible matches. Data were collected as to percentage of correct matches and time required for comparison. Each set of pre- and post-orthodontic casts was properly identified (100%) by 8 investigators, and the remaining investigator correctly matched 22 out of 25 casts (88%). These conclusions were drawn.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗