Browsing by Author "Baldwin, James J."
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Item A Bolton Analysis Comparison of Hispanic vs. Caucasian Samples in Indianapolis, Indiana(2004) Kutsch, Devon R.; Roberts, W. Eugene; Baldwin, James J.; Hohlt, William F.; Hathaway, Ronald R.; Shanks, James C.Although many studies examining tooth size discrepancy have been conducted, many were originally done on unknown populations and genders. They were also conducted on Class I ideal occlusions. Since that time, there have been many studies of the Caucasian population, but little has been done to compare the differences between Caucasian and Hispanic patients. The objective of this study was to establish whether there is a greater incidence of Bolton tooth mass discrepancies in the Hispanic population than in the Caucasian population of Indianapolis, Indiana. Secondly, the objective was to examine possible differences in the incidence of tooth mass discrepancy according to gender and dental malocclusion in the same sample. A sample of 292 pretreatment casts was measured to determine the incidence in both populations. The sample was composed of 146 Caucasian patients and 146 Hispanic patients. The patient sample was composed of 86 Caucasian females, 60 Caucasian males, 87 Hispanic females, and 59 Hispanic males. Patient's ethnicity was defined by photos and patient history. Individuals with a known mixed ethnicity were excluded. The sample was taken from patients in both the pre- and postdoctoral clinics at Indiana University School of Dentistry Section of Orthodontics, and the offices of selected private practitioners. Mesio-distal width of all teeth from first molar to first molar was measured with the mesio-buccal and disto-buccal contact areas normally being the widest area. The inter-incisal angle was evaluated utilizing lateral cephalometric radiographs. The molar and cuspid classification, overjet, overbite, and maxillary central incisor anterior-posterior dimension was measured from the dental casts. Results demonstrated that overjet, overbite, interincisal angle, molar class, and cuspid class did not have a significant effect on the Bolton discrepancy with each gender or between the two ethnic groups. Ethnicity did have a significant effect on the overall and anterior Bolton discrepancy with the ratio the Hispanics showing a significantly higher proportion of cases outside normal. Exploratory analysis also demonstrated which teeth were most discrepant. Clinicians are faced daily with the challenge of trying to produce ideal occlusions with optimal esthetics. Tooth mass discrepancies present an impediment to the clinician in trying to achieve this goal. By studying malocclusions common to a population, the clinician can more effectively treat his/her patients by being aware of potential problems that might compromise the final outcome. With the burgeoning Hispanic population in the US, this study was indicated using the Hispanic population as a patient base to ascertain how commonly used norms relate to the Hispanic population. This study demonstrated Hispanics have a significantly greater proportion of patients with a significant Bolton discrepancy. Being aware of this will allow the clinician to treat his/her patients more effectively and obtain an optimum esthetic and functional result.Item 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.Item 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.Item 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.Item Analysis of the Relationship Between Growth Hormone Receptor Polymorphism rs6180 and Craniofacial Morphological Changes Associated with Herbst Appliance Therapy(2007) Ellis, Lawrence Charles; Hartsfield, James K., Jr.; Baldwin, James J.; Foroud, Tatiana M.; Roberts, W. Eugene; Shanks, James C.Craniofacial growth results from both environmental and genetic factors over time. It would be exciting to isolate genetic factors that influence treatment responses from patients undergoing orthodontic treatment. Genetic genotyping and analysis of orthodontic patients is a new technologic advancement. The aim of this retrospective study is to examine the relationship of a specific single nucleotide polymorphism (SNP), rs6180, of the Growth Hormone Receptor (GHR) gene with various craniofacial length parameters in patients who have received Herbst appliance therapy as part of orthodontic treatment. An initial lateral cephalometric radiograph was taken along with two buccal cheek swabs. The cells obtained have undergone DNA isolation with the Puregene method in microcentrifuge tubes (Gentra Systems, Minneapolis, MN). Upon termination of functional appliance therapy (post-Herbst), a final lateral cephalometric radiograph was taken. To analyze the genetic polymorphism and determine genotype, polymerase chain reaction (PCR) and allelic discrimination were done using the 7000 Sequence Detection System (Applied Biosystems). Lateral cephalometric radiographs (initial, post-Herbst) of 25 patients were digitized and measured using the Dolphin Imaging program. Cephalometric measurements (S-N, S-A, Co-Go, Go-Gn, Ar-Gn, Go-Gn) were used to identify mandibular and craniofacial morphologic changes. Changes in Z-scores based on standards from the Michigan Growth Study were then converted to slow or normal growth status by slow being when the Z-score difference between the initial and final measurements is less than zero. The number of subjects with a slow versus normal growth status was compared to GHR polymorphism genotype. Statistical analysis of Hardy-Weinberg equilibrium and the changes in craniofacial length Z-scores in relation to a patient's genotype were performed using chi-square analysis. Results: The genotype frequencies were in Hardy-Weinberg equilibrium. Z-score differences for the S-A measurement was the only one found to be significant (p=0.005).Item 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.Item Assessment of Orthodontic Treatment Results: Two-Phase Treatment (Early Intervention) vs. One-Phase Treatment (Late Intervention)(2003) Hsieh, Tsung-Ju; Roberts, W. Eugene; Baldwin, James J.; Hohlt, William F.; Kowolik, Michael J.; Shanks, James C.There is still a lack of consensus among orthodontists regarding the degree of success of different treatment modalities applied during the early to late mixed dentition stages. The purpose of this study was to compare the treatment outcome of one-phase with two-phase treatment with objective evaluation criteria. The null hypothesis is that there is no difference in the treatment quality between early and late treatment groups, among cases finished in year 1998, 1999 and 2000 or among three Angle's Classes or between extraction and non-extraction cases. Pre-treatment and post-treatment records of all patients treated in the orthodontic clinic at the Indiana University School of Dentistry who had their treatment completed during the three years (1998, 1999, 2000) were evaluated by American Board of Orthodontics (ABO) objective grading system and clinical assessment criteria developed in the IUSD orthodontic section. The results of the study showed that there were 512 cases finished in these 3 years. Among these 512 cases the treatment was most often started at age 12, followed by age 13. Poor occlusal contact and improper third order of molars, longer treatment time, and poor dentition were major contributors that made the treatment quality poor. Early debond tended to occur more often with boys than girls. Generally Angle's Class I cases and the cases finished in year 1998 had better treatment results. Although the early treatment group had longer treatment time than late treatment group, the final treatment quality was comparable with that of the late treatment group.Item 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.Item Comparison of Root Resorption in Patients Treated With .018 Slot Brackets Versus Those Treated With .022 Slot Brackets(2002) Bailey, Spencer S.; Hohlt, William F.; Hathaway, Ronald; Baldwin, James J.; Parks, Edwin T.; Shanks, James C.Understanding the factors that increase patients susceptibility to orthodontically induced root resorption is of the utmost importance to the practicing clinician. Numerous studies have been conducted that investigated contributing and etiological factors that tend to increase the amount of external apical root resorption a patient may incur during orthodontic treatment. However, there has been little research that has attempted to determine if patients treated with different slot size orthodontic brackets exhibit the same amount of external apical root resorption. The purpose of this research was to determine if patients treated with the 0.018 x 0.025 slot size bracket and patients treated with the 0.022 x 0.028 exhibited similar amounts of external apical root resorption during orthodontic treatment. Pre and Post treatment panoramic films from 91 consecutively treated orthodontic patients from a private orthodontic practice were used for this study. Each case that was included in the study had been treated with standard edgewise brackets using the Tweed-Merrifield philosophy of treatment. Forty-three cases from the 0.018 group and 48 from the 0.022 group were obtained. Each film that was analyzed was blinded prior to measuring to minimize observer bias. Mitutoyo Digimatic® calipers accurate to the nearest tenth of a millimeter were used for obtaining tooth measurements. Measurements were made from the Cemento-enamel junction and from incisal/occlusal to most apical portion of each incisor and all first molars. Statistical analysis was performed and the results showed no significant correlation between the size of the bracket and the amount of root resorption. No significant correlations existed between the groups for patient age, time in treatment, gender, and angle classification. Statistically significant differences were noted for cases in which extraction of four bicuspids was performed. Subjects belonging to the extraction group demonstrated significantly more external apical root resorption than those in which extractions were not done. This study demonstrated that the incidence of EARR that a patient may incur during treatment is independent of the size of the slot of the orthodontic bracket.Item A Comparison of the Force-Moment Systems Generated by Orthodontic Stainless Steel T-loop and Triangular Springs(1999) Albright, David A.; Chen, Jie; Baldwin, James J.; Hohlt, William F.; Katona, Thomas R.; Shanks, James C.The force-moment systems of orthodontic T-loops have been widely described and investigated. A simpler triangular loop spring design has been employed in the graduate orthodontic clinic at Indiana University School of Dentistry. To date, no investigators have specifically examined and compared the force systems generated by these two loop configurations. The objective of this study was to compare the force systems generated by a T-loop and two different geometric shapes of triangular loops. A sample of 20 T-loops and 40 triangular loop springs were studied. The triangular loops were constructed in two different geometric configurations (n = 20 in each group) utilizing the same linear amount of wire as used in the T-loop fabrication. One set of triangular loops was the same height as the T-loop (isosceles shape); the other set was the same width as the T-loop (equilateral shape). Force and moment components along three mutually perpendicular axes (x, y, and z) were analyzed, with particular emphasis on the force system generated in the sagittal plane. The force-moment systems generated upon mesio-distal (x axis) activation were measured by a transducer connected to a computer for data collection and analysis. Statistical analysis utilized repeated measures of variance models (ANOVA). Multiple comparisons were made using Fisher's Protected Least Significant Differences at a 95-percent overall confidence level. On initial ligation, there were no significant differences between the loops in the M/F ratios in the sagittal plane (p = 0.75). For all other activation distances, the equilateral triangular loops produced greater M/F ratios than both the isosceles and T-loops (p = 0.0001), and the isosceles triangular loops generated greater M/F ratios than the T-loops (p < 0.0035).