IU Indianapolis ScholarWorks :: Browsing by Subject "Orthodontic Appliances"

Browsing by Subject "Orthodontic Appliances"

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A Torsional Analysis of Stainless Steel Orthodontic Wires
(1962) Mulligan, Thomas F.
Maximal torque and torque-twist rate were determined for straight lengths of wire. The effect of wire length on each was studied. Anti-rotational torque was determined for cuspid retraction springs, and finally, distal root torque produced by cuspid retraction springs and anterior retraction springs was determined. Torque watch gauges in combination with a Bunsen burner assembly and self-devised deflection scale were used to determine the data. Maximal torque was shown to be independent of wire length, and closely approximated the theoretically determined values, while twist was shown to be proportional to wire length. Pre-stressing followed by stress-relief produced the highest maximal torque values, while wires which received neither type of treatment exhibited the lowest values. Torque-twist rate was determined for a number of wires commonly used in orthodontics, both experimentally and theoretically. It was shown that anti-rotational torque produced by cuspid retraction springs used in the Segmented Arch Technique was not only capable of preventing cuspid rotation during distal tooth movement, but could actually move the distal of the cuspid labially on the basis of theoretical mechanics. Initial activation of anterior retraction springs used in the Segmented Arch Technique produces added distal root torque for the appliance when activated for distal tooth movement, while it appears that both cuspid and anterior retraction springs produce sufficient distal root torque to prevent forward root displacement.
An Evaluation of the Bond Strength of Recycled Orthodontic Bonded Brackets
(1981) Higgins, Duncan W.
This investigation was designed to determine the effects of recycling orthodontic bonded attachments on bond strength. It was hypothesised that the reduction of the bracket mesh wire diameter as a result of electro-polishing may affect the bond at the mesh-resin interface. Ten brackets with brazed mesh were bonded to extracted bicuspid teeth and after 24 hours the mesh-resin bond was tested to failure in tension. The brackets were recycled in an Esmadent bracket reconditioner and rebonded to 10 fresh teeth. The process was repeated until the brackets had been recycled six times each and the bond strength determined for a total of 70 teeth, with the following results. 1. The mean bond strengths for each group were not significantly different at the .05 probability level. 2. There was no significant correlation between the number of cycles and bond strength. 3. After the brackets had been recycled five times, there were areas of missing mesh around the periphery of same brackets. It can be concluded that the primary factor limiting the number of times a bracket can be reused is the widening of the bracket slot, rather than the decrease in band strength.
The Analysis of Three Space Closing Assemblies
(1976) Cook, Thomas Bowers; Garner, LaForrest D.; Shanks, James C.; Potter, Rosario H.; Dirlam, James H.; Barton, Paul
This investigation compared the spring characteristics of three space closing assemblies; the classic "Bull" loop and two new spring designs currently being used in the Department of Orthodontics at Indiana University. Using interbracket distance and the degree of gable preactivation as variables, a complete laboratory analysis was carried out on each spring design. A total of two hundred springs were tested. A statistical investigation was conducted to determine if the spring designs had significantly different load-deflection rates, moment to force ratios, and range of activation. The range of activation for all three spring designs was large enough to be of some minor importance in determining the difference in efficiency of each design. However, when the load-deflection rates and moment to force ratios of the "Bull" loop and the two new spring designs were compared, the new spring designs invariably proved to be superior. From this laboratory study, it was concluded that the two new spring designs have the potential of providing a more efficient method of orthodontic space closure.
Antero-Posterior Movement of the Maxillae with a Modified Sutural Expansion Device
(1967) Gersh, Gary Paul
It was the purpose of this study to discover if anteroposterior movement of the maxillary bones was possible. Seven cats were used as the experimental animals. An expansion device which produced a diagonal force from one maxillary cuspid to the opposite molar was inserted in five of the animals. Two animals were used as controls. The effects of the lateral and antero-posterior components of the force were studied by means of before and after models, oriented occlusal radiographs, and histologic sections. Antero-posterior movement did occur. The anterior movement was more evident than the posterior movement due to the response evoked in the premaxillary-maxillary and the maxillary-palatine sutures. The sutures which were compressed showed very little response when viewed in horizontal histologic sections as compared to the sutures which were under tension. The sutures under tension showed marked osteophytic production which generally grew parallel to the line of force application. This difference in response allowed one side to remain as an anchorage unit while the opposite side moved anteriorly. The lateral increase in width appeared to be stable. In one animal the force was removed for thirty six days prior to sacrifice. In this animal the stability of the antero-posterior movement was questionable.
Assessment of Orthodontic Treatment Results and Comparison between Fixed Lingual and Labial Appliances
(2001) Pinskaya, Yuliya B.; Roberts, W. Eugene; Baldwin, James J.; Hartsfield, James K., Jr.; Hohlt, William F.; Shanks, James C.
Interest in objective assessment of orthodontic treatment outcomes and in quality control of orthodontic treatment is increasing. In recent years, the evaluation of orthodontic treatment results has been carried out with the help of various indices or different rating systems. No published studies have used the ABO Objective Grading System for evaluation of orthodontic treatment outcomes for all cases in the clinical series. There are also very few studies, conducted mainly in Europe, that have assessed treatment results in postgraduate orthodontic clinics. There is one known study comparing treatment results between fixed lingual and labial appliances. The objectives of the present study were: first, to assess treatment outcomes in the IUSD Graduate Orthodontic Clinic for three years (1998, 1999, and 2000); and second, to compare treatment results achieved with the use of fixed lingual and labial appliances. Pre and posttreatment records (study casts, panoramic and lateral cephalometric radiographs, and extraoral and intraoral photographs) of 521 patients treated in the IUSD Graduate Orthodontic Clinic were evaluated. Treatment outcomes were assessed for a 3-year period using the ABO Grading System and IUSD Comprehensive Clinical Assessment Criteria. Statistically significant differences were found for the majority of the evaluation criteria between the selected three years. The overall quality of finished cases decreased from 1998 to 2000. This trend may reflect preferential finishing of the cases that were going well and transferring all the other cases. No assumptions regarding the overall performance of the Clinic should be made based on the results of this study. It should be remembered that these three years were selected for a particular reason. In the fall of 1997, a clinical grading program was initiated. All active cases (1997-98 academic year) were to be finished within three years. The year 2000 was the deadline to finish all active long treatment time cases. Most of the cases that were in treatment for a long time were progressing poorly and were not finally finished until 2000. This group of difficult cases contributed to the decreased quality of the finished cases and longer treatment time during the year 2000 compared to 1998 and 1999. It is anticipated that treatment outcomes will improve in 2001 since the backlog o flong treatment time cases has been cleared. The evaluation of this three-year period (1998-2000) was the baseline evaluation for comparison of finished cases for subsequent years. When comparing treatment results between fixed lingual and labial appliances, significant differences were found for only 4 of 24 parameters. These outcome differences were, mainly, due to the inherent characteristics of the lingual appliance rather than to the treatment approach of the supervising instructor. Even though statistically significant differences were found for a few parameters between two types of appliances, they did not indicate the advantages of one appliance over the other. The present study suggests that the treatment results can be as good with lingual as with labial appliances. This study also has established a baseline for comparison of clinical outcomes in the IUSD Orthodontic Clinic for subsequent years.
Bacterial Microleakage of Cemented Orthodontic Bands
(1969) Mortensen, Donald W.
The sealing properties of cemented orthodontic bands to bacteria was studied in this investigation. Bands were constructed for 90 mandibular incisors. A hole was made from the facial surface of the tooth, beneath the band, to the pulp chamber. The band was cemented on the tooth which was then sealed in a plastic tube with epoxy resin. The banded tooth encased within the plastic tube was sterilized in ethylene oxide gas and then inserted in a glass centrifuge tube containing sterile broth. A broth culture of Serratia marcescens was placed in the plastic tube and microleakage was determined by a reddish turbidity in the centrifuge tube. The cemented bands were tested with and without temperature cycling. All of the cements tested exhibited varying degrees of microleakage. At the .05 level of significance, the zinc phosphate cement (thin consistency) was found to differ from zinc phosphate (standard consistency), Hydrophosphate and Silico-Phosphate cement. Temperature cycling had a minimal effect on the thin mix of Zinc Phosphate, Zinc Oxide-Eugenol, and Silico-Phosphate cement. All assemblies which exhibited microleakage were retested after their roots were sealed with epoxy resin. None showed growth in the centrifuge tube indicating that the path of bacterial penetration was via the opening beneath the cemented band.
Comparative Tensile Strengths of Brackets Bonded to Porcelain with Orthodontic Adhesives and Porcelain Repair Systems
(1986) Eustaquio, Robert I.; Garner, LaForrest D.; Barton, Paul; Hennon, David K.; Moore, B. Keith; Muñoz, Carlos; Shanks, James C.
This study evaluated the feasibility of bonding brackets to porcelain for orthodontic purposes by measuring and comparing tensile strengths of five silane-based adhesive systems. Each adhesive system bonded mesh pad brackets to 10 glazed and 10 deglazed metal-ceramic crowns and the specimens were then thermocycled between 16 degrees and 56 degrees for 2500 cycles. Clinically relevant bond strengths, comparable to those of adhesives bonding brackets to enamel, were recorded for four of the systems compared. System l+ and Porcelain Primer had the highest mean values followed by Lee's Enamelite 500, then Vivadent's Silanit, Contact-Resin and Isopast, then 3M's Concise and Scotchprime. Most, if not all, failure sites for the four were at the bracket-resin interface. Two-way factorial analysis of variance demonstrated significant differences at P<.001 among the four adhesives but no contribution of surface effect, whether glazed or deglazed, was suggested statistically. Neuman-Keul sequential range tests showed significant differences between System l+ and the three other systems but no significant differences among the three were detected. Den-Mat's Ultrabond recorded extremely low tensile strength values and was of dubious clinical value. A t-test suggested that deglazing porcelain contributed no significant difference in strength compared with intact, glazed porcelain. All failure sites were at the porcelain-resin interface for this product. Since resin may remain bonded to porcelain following debonding, George Taub's diamond polishing paste and Shofu porcelain polishing wheels were compared as to their ability in restoring the porcelain to its original state. Because of the great adhesive bond of the resin to porcelain, craters, pits or tears may be created when resin is cleaned from porcelain with conventional scalers and pliers. The diamond paste gave a better restorative finish than the stones but the end result depended on the extent of original damage following cleaning. Orthodontists should take this point into account when considering bonding to porcelain crowns or veneers for esthetics sake where final risks may outweigh initial benefits. In a limited survey of 100 orthodontists responding to a questionnaire, 89% indicated that they have bonded or contemplated bonding to composite restored teeth, and 83% indicated that they have bonded or contemplated bonding to porcelain.
A Comparison of Frictional Forces During Simulated Cuspid Retraction on a Continuous Edgewise Archwire
(1982) Allai, W. Wesley; Garner, LaForrest D.; Sondhi, Anoop; Shanks, James C.; Swartz, Marjorie L.; Barton, Paul
This investigation was designed to compare the force (grams) required to overcome a simulated cuspid retraction assembly capable of three dimensional control during the retraction process. It was hypothesized that a significant difference in the mean retraction values exists between the newer orthodontic alloys of Nitinol, Beta-Titanium, as well as Stainless Steel. One hundred eighty bracket and archwire combinations were examined as follows: Sample # Wire Cross-section Wire Material 30 .016”x.022” Stainless Steel 30 .017”x.025” ” 30 .016”x.022” Nitinol 30 .017”x.025” ” 30 .016”x.022 Beta-Titanium (TMA) 30 .017”x.025” ” A statistically significant difference was shown to exist between all six groups examined regarding the variables of wire size and wire material. The statistical analysis revealed that increasing rectangular archwire cross-sectional size from .016"x.022" to .017"x.025” rectangular wire when simulating canine retraction using an .018" slotted Lewis bracket will lead to significantly greater functional forces. The analysis of wire materials indicated that a significant difference (p=.01) exists between rectangular Beta-Titanium (TMA), Nitinol, and stainless steel during simulated cuspid retraction utilizing a narrow .018" Lewis bracket ligated with A-lastik ligatures. The least frictional force was observed with the .016"x.022" stainless steel test cells. The largest frictional force was found in the .017”'x.025" Beta-Titanium retraction specimens. Nitinol revealed force data intermediate between stainless steel and Beta-Titanium. The maximum resistance assembly developed 2.3 times the minimum frictional force observed. The mean grams of frictional force within these test cells ranged from 55.03 grams for the .016"x.022" retraction assembly to 132.68 grams for the .017"x.025" Beta-Titanium assembly. A topographical scanning electron microscope survey of the brackets and archwires utilized was included to provide qualitative insights into the quantitative results described.
Displacement of Anchorage in Controlled Root Movement at Various Force Values
(1970) Winkler, Robert A.; Cunningham, Donald; Garner, LaForrest; Mitchel, David; Norman, Richard; Shanks, Jim
Effects of Positions and Magnitudes of Preactivation Bends on the Force Systems Generated by Orthodontic Stainless Steel T-Loop Springs
(2000) Park, Bo Young; Chen, Jie; Baldwin, James J.; Hohlt, William F.; Katona, Thomas R.; Shanks, James C.
Space closure of any kind in orthodontic treatment first needs a determination of the anchorage requirement. The clinician should control the force system accurately to achieve the differential space closure depending upon the diagnosis and treatment goals. Orthodontic T-loops have been used widely to close spaces. Several modifications have been made to achieve differential space closure. However, each modification has some clinical limitation and disadvantage. The purpose of this study is to look at the effects of preactivation bend position and magnitude on the force system and the possible implications in differential space closure. Five groups of orthodontic T-loops were studied. Each experimental group consisted of 20 T-loops and the positions or magnitudes of the preactivation bends were changed in each group. The forces and moments were measured, and the M/F ratios were computed. This study showed that the magnitude of the moment increased if (a) the preactivation position move closer to the bracket, or (b) the magnitude of preactivation is increased. There were extrusive forces acting on the side where the preactivation bends were closer to the bracket, or where the greater magnitude of preactivation existed.

Browsing by Subject "Orthodontic Appliances"

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