IU Indianapolis ScholarWorks :: Browsing by Author "Moore, B. Keith"

Browsing by Author "Moore, B. Keith"

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A Comparison of Shear-Peel Bond Forces of Flattened and Unaltered Brackets on Flattened and Curved Enamel Surfaces
(2007) Wyatt, Tracy D.; Katona, Thomas R.; Baldwin, James J.; Hohlt, William F.; Moore, B. Keith; Shanks, James C.
One aspect of bond strength testing that varies among researchers is the contour of the tooth and bracket bases that are tested. Unaltered teeth with as-manufactured brackets are the most commonly used combination. Flattened teeth with unaltered bracket bases and mechanically flattened teeth and brackets are also used. The intended purpose of this project was to determine the effect of tooth and bracket contour combinations on the shear, tension and torsional bond forces of bonded brackets. The crowns of two-hundred and four bovine incisors were potted in acrylic tubes with their facial surfaces slightly protruding. The facial surfaces of half of them were ground flat on a Wehmer model trimmer (The Wehmer Corporation, Lombard, IL). The remainder were contoured on a Wehmer model trimmer using a jig that rotated the tooth's facial surface on a radius of approximately 3 inches. One-hundred and two maxillary right central incisor brackets (3M Unitek, Monrovia, CA. Victory Series, .022 slot) were flattened, ten at a time with a 2000 N force on a self-leveling plate in the MTS Bionix testing machine (MTS Systems Corporation, Eden Prarie, MN). Another 102 brackets were unaltered. The Day 1 data set samples (shear-peel loading) were etched with 35% phosphoric acid gel and bonded with Transbond XT Light Cured Adhesive Paste (3m Unitek). This provided 17 specimens for each of four groups: curved tooth/curved bracket (C/C), curved tooth/flat bracket (C/F), flat tooth/curved bracket (F/C), and flat tooth/flat bracket (F /F). The samples were de-bonded in the MTS Bionix testing machine with the force applied parallel to the bracket base, (i.e., in shear-peel) and the peak forces were recorded. Due to large variations in the results and low forces compared with previously published studies from this laboratory, the bonding protocol and loading were altered for Day 2 testing. Rather than torsion loading, the shear-peel debond set was repeated. The following changes were made to the bonding protocol. The samples were pumiced following sanding and stored in fresh de-ionized water prior to bonding. The samples were also dried with compressed air following etching and the primer was thinned with compressed air. Following preparation the samples were debonded in the MTS Bionix testing machine and peak forces were recorded. These results were also inexplicably variable and relatively low. Day 3 samples, intended for torsion debonding, were bonded the same as the Day 2 samples except that a 3 7% phosphoric acid liquid (Reliance, Itasca IL) was used to etch the samples and a new bottle and tube of Trans bond XT Light Cured Adhesive Primer and Transbond XT Light Cured Adhesive Paste (3M Unitek) were used. The samples were also debonded in shear-peel in the MTS Bionix testing machine and peak forces were recorded. Despite the outlined efforts, these results were also scattered and relatively lower than obtained previously. An analysis of variance model was used to evaluate the bond forces and showed no statistical difference among the groups except that in the Day 2 data set the C/C group was significantly weaker than the F/F group (p= .0452). In the Day 3 data set the C/C group was also weaker than the F/F group though the results were not significant (p=.0739). There is a trend to suggest that the bracket base and crown curvatures may be important factors in determining shear bond force.
A Comparison of Three Debonding Techniques Employing Two Different Cements
(2004) McCabe, Russell; Katona, Thomas R.; Baldwin, James J.; Hohlt, William F.; Moore, B. Keith; Shanks, James C.
The theory and practice of bonding orthodontic brackets to enamel has become the accepted standard. However, regardless of the adhesive of choice, much controversy exists regarding bond strength values and testing protocols. Most bond strength testing has been done in either shear/shear-peel or tension. Some studies have used shear and tension and very few have used shear, tension and torsion. Some authors contend there is no difference in the stress required to produce bond failure by either tensile or shear test models. However, it has been shown that stress is not distributed uniformly during loading and each mode of strength testing produces unique stress patterns. Additionally, since in the oral cavity brackets are subject to shear, tensile and torsion forces, it seems logical that a complete picture of bond strength could not be formulated without all three test methods. Confounding the issue is the fact that adhesive research is being performed in non-standardized manners making it impossible to compare results among different researchers. Despite the vast amount of information presented in articles, this has resulted in a lack of consensus regarding clinical bond strength values. The purpose of this investigation was to evaluate the three debonding techniques (shear-peal, tension, torsion) using stainless steel brackets and two different bonding agents (traditional resin cement vs. resin reinforced glass ionomer). The hypotheses of this investigation were (1) the relative shear-peal, tensile and torsional bond strengths will show consistent results and (2) cement type will have a significant effect on the bond strengths. One hundred sixty-two bovine incisors were randomly assigned to 6 groups of 27 specimens per group. Teeth were bonded with either a resin composite adhesive or a resin reinforced glass ionomer cement following manufacturers' instructions. Bonding was performed under controlled temperature and humidity (71 °F± 2° and 56% RH± 5%). In addition, specimens were bonded utilizing a bonding jig that held the thickness of the adhesive constant at 0.006 inches. All groups were tested to failure using the MTS Bionix machine in shear, tension and torsion. The results showed that the resin composite had a significantly higher load at failure in shear and torque than the resin-modified glass ionomer. However, in tension, no significant difference was found between the two cements. Additionally, analysis of relative strength indicated a difference between shear strength and tension suggesting that testing mode influences bond strength values. It is the conclusion of this study that the load at failure for resin composite and resin-modified glass ionomer are not consistent and depend on the loading mode.
A Comparison of Three Debonding Techniques Employing Two Methods of Tooth Preparation
(2003) Long, Robert W.; Katona, Thomas R.; Baldwin, James J.; Hohlt, William F.; Moore, B. Keith; Shanks, James C.
Traditionally, orthodontic adhesive systems consisted of three separate agents: an enamel conditioner, a primer solution, and an adhesive resin. Newer systems have combined the conditioning and priming agents into a single acidic primer solution. The purpose of this investigation is to evaluate the three debonding techniques (shear-peel, tension, torsion) using stainless steel brackets and two different methods of tooth preparation (37% phosphoric acid+ primer vs. self-etching primer). The null hypotheses of this investigation are (1) the method of tooth preparation will not have a significant effect on the bond strengths and (2) the relative shear-peel, tensile and torsional bond strengths will show consistent results. One hundred and fifty bovine incisors were randomly assigned to 6 groups of 25 specimens per group. Teeth were prepared for bonding by employing either (1) acid-etching with 37% phosphoric acid+ primer or (2) self-etching primer. The brackets were bonded with a resin composite adhesive under controlled temperature and humidity conditions at 74°F ± 2 and 54% ± 5 RH. In addition, specimens were bonded utilizing a bonding jig that held the thickness of the adhesive constant at 0.152 mm. All groups were tested to failure using the MTS Bionix machine. Results from this study showed that the prime-etching method of tooth preparation had significantly greater mean shear-peel bond strength than did the self-etch method and that the prime-etching method had significantly less mean tensile bond strength than did the self-etch method; however there were no significant differences in torque strengths between the two methods of tooth preparation. In addition, results for the true ratio of mean forces showed shear-peel bond strengths lies clearly above the confidence intervals for the other debonding measures, thus the three measures of debonding are dissimilar in the comparison of the two tooth preparation methods. Thus, both null hypotheses were rejected.
A Frictional Evaluation of a New Surface-Modified Titanium Orthodontic Bracket
(2000) Olsen, Marc E.; Oshida, Yoshiki; Andres, Carl J.; Katona, Thomas R.; Moore, B. Keith; Roberts, W. Eugene; Shanks, James C.
Sliding mechanics is a popular method of moving teeth orthodontically. Sliding mechanics refers to the guiding of a tooth by means of the bracket slot along an archwire in response to some applied force. This concept of tooth movement is subject to both static and kinetic friction. An accurate evaluation of an appliance's frictional properties enables a clinician to identify applications where the utilization of a new appliance may be advantageous. The aim of this study was to evaluate the frictional properties of this new surface-modified titanium orthodontic bracket compared with a traditional stainless steel orthodontic bracket and a currently available non-surface modified titanium bracket. Fifteen brackets (5 Stainless steel, 5 Titanium, 5 Coated Titanium) were combined with five archwires from each material type (SS, NiTi, βTi). Frictional evaluation was completed on each bracket material utilizing .021" x .028" size archwire materials in a specially designed apparatus under wet conditions. The frictional resistance was measured on an Instron Universal Testing machine (Instron Corp, Canton, Mass). The brackets/archwire samples were tested one at a time individually. In addition, a single bracket/ archwire sample from each group was repeatedly tested five times. Measurements were made at every 0.1mm for 30mm via a computer attached to the testing machine. An ANOV A was used to determine differences between groups. The results indicate that stainless steel brackets exhibited significantly better static and kinetic frictional properties than the titanium brackets. Stainless steel wires possessed superior frictional properties to NiTi and β-Ti wires. NiTi wires were generally superior than β-Ti wires. As brackets and archwires were reused, the overall frictional values showed a distinct trend to increase.
Bond strength evaluation of two resin cements with two adhesives and analysis of mode of failure
(2009) Mohan, Preethi; Platt, Jeffrey A.; Chu, Tien-Min Gabriel; Moore, B. Keith; Taskonak, Burak; Matis, Bruce A.; Cochran, Michael A.
Cementing of indirect restorations with resin cements generally requires the pre-treatment of dentin with an adhesive. When dual-cured or chemical-cured resin cements are used with these single-step adhesives, incompatibility issues exist. This has resulted in manufacturers making chemical changes in their products. Kerr Dental markets a new resin cement, Nexus Third generation (NX3), which utilizes a proprietary redox system different from the second generation of composite luting agent (NX2). The aim of this study was to evaluate microtensile bond strength and mode of failure of NX3 and NX2 with two different adhesive systems (total-etch and self-etch) after 1 week and after 3 months of storage. Methods: Sixty-four non-carious teeth were sectioned to expose the dentin using a low-speed saw. Dentin surfaces were ground with 320-grit SiC paper. The adhesives Optibond Solo Plus (SOL), and Optibond All In One (AIO) were applied, and resin cements (NX2, NX3) were used to lute 4-mm composite discs to the treated dentin surfaces. Microtensile bond strength was determined at 1 week (IM) and after 3 months (3MON) of storage using a universal testing machine (MTS). All specimens were examined under the stereomicroscope to determine the mode of failure. Random specimens from each failure group were examined using scanning electron microscopy. Statistical Analysis: Comparisons between the treatment combinations for differences in microtensile bond strength were performed using Weibull-distribution survival analysis. Comparisons between the treatment combinations for differences in the failure mode were performed using Fisher’s Exact tests. The group NX3 SOL IM (30.5 MPa) had significantly higher bond strength than NX3 SOL 3MON (13.4 MPa); NX3 AIO IM (11.3MPa); NX3 AIO 3MON (8.2 MPa; NX2 AIO 3MON (5.8 MPa); NX2 SOL IM (6.3 MPa), and NX2 SOL 3MON (3.2 MPa). The group NX2 AIO IM (19.3 MPa) was not significantly different from NX3 SOL IM. The group NX2 SOL 3MON and group NX2 SOL IM had a significantly higher percentage of teeth with mixed failure than all of the other groups. None of the other groups had significantly different failure mode. The group NX3 SOL IM had 90-percent beam survival beyond 17 MPa, and NX2 AIO IM had 50 percent of beams surviving beyond 17 MPa, a better performance. For all the other groups, more than 50 percent of beams failed below 17 MPa. Results show high evidence of degradation for all groups considered in this investigation. The use of these types of cement adhesive combinations in clinical situations should be used with this understanding.
Clinical Evaluation of Glass Ionomer Cement as an Adhesive for the Bonding of Orthodontic Brackets
(1988) Miller, James R.; Garner, LaForrest D.; Moore, B. Keith; Shanks, James C., Jr.; Barton, Paul; Potter, Rosario H.
Glass ionomer cement has been shown in previous studies to retard decalcification and caries formation. This cement would be valuable in orthodontics if it proved to have adequate adhesive properties. Therefore, this study was designed to determine if there is a significant difference in the failure rate of brackets attached to teeth using a glass ionomer cement, Ketac-fil, and the failure rate of brackets attached to teeth using a conventional orthodontic adhesive system, Rely-a-bond. Six patients in the Department of Orthodontics at Indiana University School of Dentistry participated in this study. Each patient had 16 to 20 teeth available for bracketing. Direct-bond orthodontic brackets were attached to one-half of each participant's available teeth using Ketac-fil. Rely-a-bond was used to bond brackets to the remaining half of the teeth. Fifty-three brackets were placed with Ketac-fil, and 53 with Rely-a-bond. This study lasted a minimum of ten weeks for each patient. The following observations were made: 1) The failure rates for brackets attached with Ketac-fil and those attached with Rely-a-bond. 2) The type of bracket failure for brackets bonded with Ketac-fil. 3) Pre-study and post-study decalcification patterns of teeth with brackets attached with Ketac-fil. The bracket failure rate was 3.77% for the Ketac-fil group and 5.66% for the Rely-a-bond group. There was no significant difference between the failure rates of these two groups at the alpha = 0.05 level when tested with the Fisher Exact Probability Test. Of the two brackets that failed in the Ketac-fil group, only one was available for examination and it demonstrated a definite adhesive type of bracket failure. With respect to decalcification patterns, no obvious change in pattern occurred for teeth in the Ketac-fil group. There was no statistical difference between the failure rates of brackets attached with Ketac-fil and those attached with Rely-a-bond. Previous studies have shown that glass ionomer cements release fluoride and that this may retard decalcification and caries formation. Decalcification and caries formation around the margins of orthodontic brackets have been identified as potential risks of orthodontic treatment. Thus, the use of a glass ionomer cement as a bonding agent in orthodontics might reduce these potential risks without compromising the attachment of the brackets to teeth. This study provides the basis for more extensive clinical trials of glass ionomer cements as bonding agents for direct-bond orthodontic brackets.
A clinical study of sealants polymerized with two different light sources
(2004) White, Marcia Stoddart; Avery, David R.; Platt, Jeffrey A., 1958-; Moore, B. Keith; Weddell, James A. (James Arthur), 1949-; Sanders, Brian J.; Matis, Bruce A.
This clinical study investigated the efficacy of the new LED LCU technology when compared to that of the QTH LCU by evaluating retention and wear of Clinpro (3M ESPE) sealant material over six months of function. This study was designed as a split mouth, randomized clinical study. Sealants were placed and polymerized on contralateral teeth of 35 patients, 33 of which successfully completed the study. The sealants were evaluated for clinical retention at baseline, three months, and six months by two evaluators. For the wear analysis, the area of the sealant wear at six months is reported. Nine pairs of molars and 22 pairs of premolar teeth were used. This sample size is smaller than the original sample used for clinical evaluation, because a number of the baseline impressions had to be discarded due to poor impression quality. Subsequent impressions were taken at three months, and six months. Epoxy replicas were made from the impressions and the occlusal surface of each replica was digitized using SigmaScan software. A cummulative legit model was applied to the clinical data, and a linear model was applied to the wear analysis. The results for clinical retention over the six months of function were as follows. At Baseline, for the QTH, 97.3 percent of the teeth received an Alpha score; 2.7 percent received a score of B. For the LED, 87.7 percent received a score of A; 12.3 percent received a score of B. At three months follow-up, for the QTH, 93.1 percent received a score of A; 6.9 percent received a score of B. For the LED, 86.1 percent received a score of A; 12.5 percent received a score of B, and 1.14 percent received a score of C. At six months follow-up, for QTH; 91.7 percent received a score of A; 8.3 percent received a score of B. For the LED, 83.3 percent received a score of A; 15.3 percent received a score of B, and 1.14 percent received a score of C. The hypothesis was that there would be no significant difference in clinical retention and wear of Clinpro's sealant polymerized with the QTH or the LED light sources over six months of function. Based on the results of this clinical study, the following conclusions can be made: 1) At baseline, Clinpro's sealant polymerized with QTH light source showed marginally significant better retention than LED light source (p-value 0.05001). 2) There was no significant difference between light sources for sealant clinical retention at three-month and six-month follow up visits. 3) Wear analysis resulted in marginally significant more wear for molar sealants polymerized with LED LCU (p-value 0.0755). 4) Wear analysis showed no significant difference for premolar sealants polymerized with either light source.
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 hardness and abrasion resistance of two sealant materials after polymerization from different distances by different light sources
(2008) Ritchie, Craig D.; Dean, Jeffrey A.; Avery, David R.; Sanders, Brian J.; Weddell, James A. (James Arthur), 1949-; Platt, Jeffrey A., 1958-; Tomlin, Angela; Moore, B. Keith
BACKGROUND The efficacy of sealants to aid in the prevention of pit and fissure caries is well documented. In order for the sealants to be effective, they must be placed properly and retained for as long as possible. Clinicians must be aware that the proper placement of sealants is technique-sensitive and must be well controlled in order to achieve the best results. This study aims to determine if certain variables have an effect on curing of the sealant material to a degree that would compromise its integrity, strength, and longevity. METHODS AND MATERIALS Two commonly used sealant materials Ultraseal XT (Ultradent Products Inc., South Jordan, UT) and Delton (Dentsply International, Woodbridge, Ontario, Canada) were chosen and tested for microhardness and abrasion resistance after they were polymerized. This study did not focus on the materials themselves, but rather the technique by which they were polymerized and what effect this had on the materials. Three separate light sources, a traditional halogen light (QHL 75, Dentsply International, Woodbridge, Ontario, Canada), and two newer LED lights (Ultralume LED, Ultradent Products Inc., South Jordan, UT; and 3M Freelight LED, 3M Corp, St Paul, MN) were used in this study. The materials were then cured with each light at each of three different distances: contact (0.5 mm), 2 mm, and 10 mm. The effects of light source variation and distance from the material at the time of polymerization was then evaluated for any significance to sealant placement technique. Specimens were tested for each variable combination of sealant material, light source, and distance between the two while curing. Six samples were tested for each variable grouping for abrasion resistance, and four separate san1ples were tested fron1 the san1e grouping for Knoop hardness. The results were analyzed for significance to determine if certain techniques are or could be beneficial or damaging to the quality of care provided by today's practitioners. RESULTS It was found that materials and light sources varied in combination and with different techniques (e.g., distance). In general, the top surface polymerized best when cured at a distance of 2 mm to 10 mm, while the bottom surface polymerized best at a distance of 0.5 mm. The halogen light consistently outperformed the two LED lights, with the 3M LED consistently producing the worst results. CONCLUSIONS The halogen curing light used in this study outperformed the LED lights in almost every category, despite the LED light manufacturer's claims of equality. For more reliable polymerization, the halogen light should be used. SIGNIFICANCE The practitioner must be aware of the material that he/she is using and how the chosen light source polymerizes that material. Manufacturers' claims and recommendations cannot be trusted to accurately produce the best results with every product on the market today, sometimes not even with the manufacturers' own products. It is crucial for practitioners to be well versed and knowledgeable about the products that they use, based on current research and not manufacturers' claims.
Comparison of Tensile Bond Strengths of Glass Ionomer Cements Using Hydroxyapatite Coated and Uncoated Orthodontic Brackets
(1993) Ng, Richard I. Cheng Hin; Hohlt, William F.; Moore, B. Keith; Oshida, Yoshiki; Garetto, Lawrence P.; Roberts, W. Eugene; Shanks, James C.
The use of glass ionomer cements (GIC) in orthodontics as a bonding agent has been receiving considerable attention due to its favorable properties, ie., physico-chemical adhesion to enamel, fluoride leaching capabilities and less traumatic bonding procedure to tooth structure. GIC ability to bond to the hydroxyapatite (HA) in the tooth enamel was tested utilizing an HA coated bracket developed by American Orthodontics. This study compared in vitro tensile bond strengths of four dental adhesives: Ketac-cem™ (KC), Vitrebond™ (VB), Transbond™ (TB) or Unite™ (UN), when used to bond to HA coated brackets and non-HA coated brackets. Bovine incisors were divided into eight groups of 20 specimens each. Each group included either an HA coated or non-HA coated bracket and one of the four adhesives. The brackets are manufactured with a Tricalcium Phosphate (TPC) coating, which is converted to an HA coating by the addition of -OH during autoclaving. The coated and non-coated brackets were bonded to the bovine teeth, which were embedded in epoxy resin blocks to fabricate the testing specimen. All of the specimens were stored in distilled water at room temperature for two weeks. This was followed by thermocycling after which the specimens were returned to water storage for an additional two weeks. The specimens were tested in tension on an lnstron Testing Machine until bond failure occurred. Mode of bond failure was determined visually by light microscope. The mean tensile bond strengths for KC and VB were each significantly less (p< 0.05) than the other three materials, while UN and TB were not significantly different. KC was the weakest at 0.68± 0.31 MPa, while UN was the strongest, 4.38±0.84 MPa. When comparing the GIG alone, there was a significant difference (p<0.0001) between the VB and the KC. The resins were not significantly different from each other. Differences between coated and non-coated were significant at p<0.05 with the noncoated brackets having the higher strength. Adhesive failure at the bracket interface for the two bracket types showed no difference for KC. TB and UN showed this type of failure significantly more with the coated brackets (p<0.05), and VB showed the opposite and more failure with non-coated brackets (p<0.01). The tensile bond strength of GIG continues to be significantly less than those of existing resins. The bond failure also revealed a high degree of within group variability. Trends relating failure mode to tensile bond strength could not be established. Greater bond strengths with the coated brackets and the GIG were not shown; however in the case of VB, the tendency for the coated brackets to fail less frequently at the bracket adhesive interface shows some promise. Further studies of these coated brackets are still warranted.

Browsing by Author "Moore, B. Keith"

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