IU Indianapolis ScholarWorks :: Browsing by Author "Katona, Thomas R."

Browsing by Author "Katona, Thomas R."

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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.
An analytical approach to 3D orthodontic load systems
(The Angle Orthodontist, 2014-09) Katona, Thomas R.; Isikbay, Serkis C.; Chen, Jie; Department of Orthodontics and Oral Facial Genetics, IU School of Dentistry
OBJECTIVE: To present and demonstrate a pseudo three-dimensional (3D) analytical approach for the characterization of orthodontic load (force and moment) systems. MATERIALS AND METHODS: Previously measured 3D load systems were evaluated and compared using the traditional two-dimensional (2D) plane approach and the newly proposed vector method. RESULTS: Although both methods demonstrated that the loop designs were not ideal for translatory space closure, they did so for entirely different and conflicting reasons. CONCLUSIONS: The traditional 2D approach to the analysis of 3D load systems is flawed, but the established 2D orthodontic concepts can be substantially preserved and adapted to 3D with the use of a modified coordinate system that is aligned with the desired tooth translation.
Biology of biomechanics: Finite Element Analysis of a Statically Determinate System to Rotate the Occlusal Plane for Correction of Skeletal Class III Openbite Malocclusion
(Elsevier, 2015-12) Roberts, W. Eugene; Viecilli, Rodrigo F.; Chang, Chris; Katona, Thomas R.; Paydar, Nasser H.; Department of Orthodontics and Oral Facial Genetics, IU School of Dentistry
Introduction In the absence of adequate animal or in-vitro models, the biomechanics of human malocclusion must be studied indirectly. Finite element analysis (FEA) is emerging as a clinical technology to assist in diagnosis, treatment planning, and retrospective analysis. The hypothesis tested is that instantaneous FEA can retrospectively simulate long-term mandibular arch retraction and occlusal plane rotation for the correction of a skeletal Class III malocclusion. Methods Seventeen published case reports were selected of patients treated with statically determinate mechanics using posterior mandible or infrazygomatic crest bone screw anchorage to retract the mandibular arch. Two-dimensional measurements were made for incisor and molar movements, mandibular arch rotation, and retraction relative to the maxillary arch. A patient with cone-beam computed tomography imaging was selected for a retrospective FEA. Results The mean age for the sample was 23.3 ± 3.3 years; there were 7 men and 10 women. Mean incisor movements were 3.35 ± 1.55 mm of retraction and 2.18 ± 2.51 mm of extrusion. Corresponding molar movements were retractions of 4.85 ± 1.78 mm and intrusions of 0.85 ± 2.22 mm. Retraction of the mandibular arch relative to the maxillary arch was 4.88 ± 1.41 mm. Mean posterior rotation of the mandibular arch was –5.76° ± 4.77° (counterclockwise). The mean treatment time (n = 16) was 36.2 ± 15.3 months. Bone screws in the posterior mandibular region were more efficient for intruding molars and decreasing the vertical dimension of the occlusion to close an open bite. The full-cusp, skeletal Class III patient selected for FEA was treated to an American Board of Orthodontics Cast-Radiograph Evaluation score of 24 points in about 36 months by en-masse retraction and posterior rotation of the mandibular arch: the bilateral load on the mandibular segment was about 200 cN. The mandibular arch was retracted by about 5 mm, posterior rotation was about 16.5°, and molar intrusion was about 3 mm. There was a 4° decrease in the mandibular plane angle to close the skeletal open bite. Retrospective sequential iterations (FEA animation) simulated the clinical response, as documented with longitudinal cephalometrics. The level of periodontal ligament stress was relatively uniform (<5 kPa) for all teeth in the mandibular arch segment. Conclusions En-masse retraction of the mandibular arch is efficient for conservatively treating a skeletal Class III malocclusion. Posterior mandibular anchorage causes intrusion of the molars to close the vertical dimension of the occlusion and the mandibular plane angle. Instantaneous FEA as modeled here could be used to reasonably predict the clinical results of an applied load.
Bracket, ligation, and misaligned straight wires effects on load systems during orthodontic sliding mechanics
(2015-07) Hannah, Richard D.; Katona, Thomas R.
Objective: The objectives of this study were to measure and compare the complete, not solely friction, load components (forces and moments) experienced by brackets as they slide along straight wires that are angled relative to the path of bracket travel. Materials and Methods: Three types of brackets (stainless steel mandibular canine and central incisor, and an all-ceramic mandibular canine) were ligated with stainless steel or elastomeric modules to 2 sizes of stainless steel wire (0.021” x 0.021” and 0.016” x 0.016”) at 0°, 1° and 2° bracket-wire misalignments. All 3 force and 3 moment components experienced by the brackets were measured as they slid along the wire. Results: Overall, all 36 permutations of the 3 brackets, 2 ligations, 2 wires and 3 alignments produced statistically different (predominantly P < .0001) load components on the bracket. Conclusions: The type of bracket, wire, ligation, and relatively small misalignments (1° and 2°) between bracket and wire affect all force and moment components applied to the bracket. Traditional friction-focused “pull through” studies miss the attendant effects on the other 5 load components.
Cell Kinetics of Osteoblast Histogenesis in Evolving Rabbit Secondary Haversian Systems Using a Double Labeling Technique with [³H]-Thymidine and Bromodeoxyuridine
(1995) Sim, Yeongsuk; Roberts, Eugene; Garetto, Lawrence P.; Katona, Thomas R.; McDonald, James L.; Seifert, Mark F.
The mechanism for internal cortical bone remodeling is orchestrated by the evolving secondary Haversian systems (SHSs), which originate on the surfaces of Volkmann's canals. During this coupled process, a cortical tunnel advances by the cutting cone of osteoclasts and closes by the bone-forming trail of osteoblasts. This study investigated the hypothesis that osteoblast histogenesis, within evolving SHSs of larger animals, is a vascular-related process, i.e., less differentiated osteogenic cells reside in close proximity to the advancing central blood vessel (CBV) while differentiating osteoblast precursors migrate toward the bone surface and become osteoblasts. Using a double-labeling method with [3 H]-thymidine and bromodeoxyuridine (BrdU), this study examined cell kinetics in 120 SHSs per rabbit at 12 hour intervals up to 72 hours after labeling. A total of 7 rabbits were injected with alizarin complexone (-1 O days: 20 mg/kg/day), tetracycline (-3 days: 10 mg/kg/day), [3H]-thymidine (time zero: 0.25 μCi/gm), and BrdU (1 hour before sacrifice: 25 mg/kg). The femoral midshaft was used for undecalcified fluorescent microscopic analysis of new bone vs. old bone and two adjacent diaphyseal tissues were demineralized for nuclear volume morphometric analysis of cells via light microscopy. Evolving SHSs demonstrating intense remodeling activity were selected for detailed cell kinetic analysis. The results showed that BrdU labeled cells were consistently located at the leading edge of the CBV (within 160 μm of its tip) and that the [3H]thymidine labeled cells were progressively left behind the advancing CBV (160 μm from the tip of CBV by 72 hours). The labeling indices (sampled 1 hour after labeling) between BrdU (10.6 ± 0.3 %) and [3H]-thymidine (14.4 ± 1.3 %) were comparable. Lightly labeled A+A' cells (identified as osteoprogenitor cells) remained in close approximation to the surface of the CBV (within 25 μm) and C+D cells (preosteoblasts) were located closer to bone-forming surfaces (~50 μm away from the CBV). The number of osteoblasts were increased up to 60 hours and about 22.5 ± 6.6 % of them survived to become osteocytes. The B cell compartment, characteristic of osteogenic tissues with a dense connective tissue component such as the periodontal ligament (POL), was essentially absent in the SHSs in this study. Although the direction of evolving SHSs was highly variable (caudally directed: 53.4 ± 11.2 % and rostrally directed: 41.6 ± 8.1 %), the osteogenic process along the advancing CBV was remarkably consistent. These results support the hypothesis that osteoblast histogenesis, associated with cortical bone remodeling, is a vascular-oriented differentiation process closely related to the internal angiogenesis within the evolving SHS. The primary proliferating region supporting osteogenesis was consistently located at the advancing tip of the CBV, suggesting the presence of a self-renewing, perivascular proliferative pool of cells accompanying the advancing vessel. In addition, a secondary proliferating region of cells trails the advancing CBV, providing for lateral migration of preosteoblasts to bone surfaces where they complete their development into functional osteoblasts. This study provides further insight into the similarities and differences in osteoblast histogenesis within evolving SHSs from adult rabbits and the more extensively studied rat POL model.
The combined effects of salivas and occlusal indicators on occlusal contact forces
(Wiley, 2019) Beninati, Christopher J.; Katona, Thomas R.; Orthodontics and Oral Facial Genetics, School of Dentistry
Background Some occlusal detection products are designed for use on dry teeth, but this is not always achieved. Others are suited for dry and wet applications. Objective The objective of this study is to assess the combined effects, on occlusal contact forces, of two previously studied affecting variables—occlusal detection products and saliva. Methods We used a full‐arch dentiform with three occlusal detection products (an articulating film, an articulation paper and T‐Scan) in combination with human (HS) and an artificial saliva. The maxillary arch assembly, weighing ~54 N (the maximum bite force), was lowered onto (occlusion) and lifted off (disclusion) of the mandibular arch through 10 cycles by a mechanical testing machine. The forces and moments acting on the mandibular arch were continuously recorded by a load cell that supported it. Results The maximum values of Flateral (the in‐occlusal plane component of the occlusal contact force) were analysed by occlusion/disclusion separately using one‐way ANOVA, with factor for group type to identify the significant effect of salivas on products, effect of products, effect of salivas with products, effect of human saliva. A difference in occlusion and/or in disclusion was considered different. Statistical differences (P < 0.0001) in Flateral were found in: dry product vs product + HS, dry product vs product + artificial saliva (with articulating film and T‐Scan) and HS vs product + HS (with articulation paper and T‐Scan). Conclusion All products were affected by the salivas, except articulation paper by artificial saliva.
Comparing a New Rating of Malocclusion to the PAR Index and to the Subjective Evaluation of Experienced Orthodontists
(2003) Benedict, Brian W.; Roberts, W. Eugene; Baldwin, James J.; Hohlt, William F.; Katona, Thomas R.; Shanks, James C.
Indices to assess malocclusion have been developed for either rating the 'severity of malocclusion' or for prioritizing a patient's need for orthodontic treatment. Most of these indices evaluate the malocclusion through examination of one or two of the following diagnostic records: dental casts, photographs, or clinical exam. However, no prior research had attempted to incorporate all of the above pretreatment orthodontic diagnostic records routinely taken for treatment evaluation. Pretreatment records (dental casts, intra-oral photographs, extra-oral photographs, panoramic radiograph, and a cephalogram, of sufficient quality to be reliably assessed) of 50 completed subjects treated at IUSD Graduate Orthodontic Clinic were evaluated. Subject criteria were a complete set of pretreatment orthodontic records, white non-Hispanic descent in the permanent dentition, absence of any craniofacial anomalies and known pathology. The 3M Unitek TM cephalometric protractor and electronic digital calipers accurate to the nearest tenth of a millimeter were used for measurements. Thirty-six measurements (11 cephalometric, 4 panoramic, 13 dental cast, and 8 photographic) were scored and combined into a total score that represents the new index. The peer assessment rating index (PAR Index) and a subjective ranking of 3 experienced orthodontists (each having more than 20 years of clinical orthodontic experience) were completed on all subjects for determining validity of the new index. All scoring methods were repeated on a subset of 10 random subjects to determine reliability. Statistical analysis showed significant correlations for the ability of the new index to detect severity of malocclusion. Also, the study showed a higher correlation for the new index in representing the experts' rankings than did the PAR index. It is the conclusion of this investigation that the new index is a valid index of malocclusion that more closely reflects experienced orthodontists rankings than the PAR index.

Browsing by Author "Katona, Thomas R."

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