IU Indianapolis ScholarWorks :: Browsing by Author "Roberts, W. Eugene"

Browsing by Author "Roberts, W. Eugene"

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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.
A Cephalometric Study of Non-Cleft Parents of Children with Cleft Lip, Cleft Lip and Palate, and Cleft Palate : Evidence to Support a Different Etiology for Isolated Cleft Palate Versus Cleft Lip?
(1993) Sadler, Charles A., Jr.; Ward, Richard E.; Bixler, David; Hathaway, Ronald R.; Shanks, James C.; Roberts, W. Eugene
Cleft lip with or without cleft palate (CLI P) and isolated cleft palate (CP) have been shown to be separate epidemiologic and embryologic entities. Furthermore, it has been proposed that noncleft biologic parents of children with facial clefts may demonstrate craniofacial differences genetically predisposing them to pass on the cleft phenotype to their offspring. With these two hypotheses in mind, the objective of the present study was to determine if differences exist in the craniofacial morphology between parents of CL/P children and parents of CP children. Twenty-seven measurements were obtained from anterior-posterior (AP) cephalograms on 127 biologic parents of sporadic CL/P and CP children. Each measurement was compared with sex and age-matched normals, and Z-scores were determined. The mean Z-scores for each group were tested for significant differences from normal and from each other. In agreement with past literature, the craniofacial morphology of parents of cleft children was generally found to have greater facial widths and shorter facial heights. Differences between the findings of the present study and the past literature are discussed. Although CL/P and CP are thought to be separate entities, differences between the parents of CL/P and CP children were not statistically evident.
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.
A Manpower Study of Orthodontic Specialists for the State of Indiana
(1992) Clark, David B.; Roberts, W. Eugene; Arbuckle, Gordon R.; Garner, LaForrest D.; Garetto, Lawrence P.; Shanks, James C.
Dental manpower has been studied at national, state and local levels.2, 4, 6, 11, 14, 15, 17-19 Manpower studies of orthodontic specialists also have been conducted,1, 5, 13, 16 but there has been no recent manpower study relative to orthodontic specialists in Indiana. The purpose of this study was to evaluate the busyness and distribution of orthodontic specialists in Indiana and project the need for orthodontists. In early 1990 a survey questionnaire was mailed to Indiana orthodontists. A telephone survey of orthodontic receptionists/appointment clerks was conducted during the same time period to obtain a separate source of data relative to practice busyness and to help evaluate the reliability of the mailed survey questionnaire. The distribution of orthodontists was evaluated by comparing the state population-to-orthodontist ratio to county and regional ratios. The response rate of the mailed survey questionnaire was 91 percent. The ages of orthodontists were evenly distributed with the exceptions of the 46-50 year age group and groups approaching retirement ages. The perceived level of busyness was low with a busyness index of 1.32. A relatively short wait was necessary to examine and start new patients, and few reported a waiting list. There was a high response emphasizing no need for additional orthodontists. Seventy percent felt that they were not busy enough; 99 percent reported that they would like more patients; and many desired large numbers of additional patients (41 or more). A large number of orthodontists had satellite offices or were considering establishing satellite offices with an insufficient patient base listed as the primary reason. There was a significant difference between the number of additional patients desired based on the age of the orthodontist. More orthodontists reported that patient loads were remaining the same or declining rather than increasing. The present data did not support the premise that the number of patients started was less than that seen in previous studies, suggesting that the low perception of busyness may be related to other factors such as a more recent decline in patient load, improved efficiency, decreased profitability or a combination of these or other factors. The telephone survey differed significantly from the mailed survey questionnaire indicating a possible bias in the survey questionnaire. A geographic maldistribution of orthodontists in Indiana was found. A slight increase in the number of orthodontists over the next decade would be necessary to maintain the present population-to-orthodontist ratio. However, the declining child population, representing the majority of orthodontic patients, will require a reduction in the number of orthodontists to maintain the present adjusted population-to-orthodontist ratio or patient-to orthodontist ratio over the next two decades.
A Study of Craniofacial Asymmetry in Monozygotic and Dizygotic Twins Using Posteroanterior Radiographs
(2002) Russell, Jennifer A.; Hartsfield, James K., Jr.; Everett, Eric T.; Roberts, W. Eugene; Shanks, James C.; Ward, Richard E.
This project investigated craniofacial asymmetry in a prospective study among monozygotic (identical) versus dizygotic (fraternal) twins and sibling pairs. Posteroanterior radiographs that had previously been collected were used in this study and the zygosity of the twins had previously been determined. We hypothesized that in this study measuring craniofacial asymmetry there would be a greater concordance between monozygotic twins than between dizygotic twins for each of the variables measured. If there were some genetic component to asymmetry, we would expect to find a greater correlation between monozygotic versus dizygotic twins and sibling pairs since monozygotic twins are genetically identical and the dizygotic twins and siblings share on average fifty percent of their genes. If there are no statistically significant differences between the monozygotic and dizygotic twin correlations as shown from the heritability value, one could conclude that genetic factors are not important in the development of craniofacial asymmetry. This information is clinically significant. If we find that environment plays the predominant role in the development of asymmetry, one would conclude that clinicians should be vigilant about employing a treatment plan that will modify the environment while an asymmetry is developing. Since the zygomatico-frontal sutures and crista galli were found to be relatively symmetrical landmarks in a previous investigation by Harvold, a horizontal axis was constructed through the zygomatico-frontal sutures and a perpendicular vertical axis was constructed through crista galli. Perpendicular distances of ten bilateral structures were measured from the vertical reference line. Two methods of evaluating subjects' head positioning were used and compared. Any subject that was found to have excessive rotation of their head was excluded from the sample. After a preliminary analysis it was found that the horizontal distances were strongly correlated to patient positioning even after subjects determined to have excessive rotation of the head were eliminated from the sample. For this reason, vertical measurements of eight bilateral landmarks were made perpendicular to the reference line constructed through the zygomatico-frontal sutures. Using Statistical Package for the Social Sciences, the magnitude of craniofacial asymmetry was evaluated by calculating the absolute (non-signed) asymmetry values (IL-RI) for each of the ten horizontal and eight vertical variables. The horizontal and vertical variables were evaluated for any directional asymmetry to determine if the right or left side is consistently larger by calculating signed asymmetry values (L-R) for each of the ten horizontal and eight vertical variables. Since the subjects vary in size, relative differences were subsequently calculated. The relative difference was calculated by dividing the right-left absolute difference by half the sum of the right and left measurements [IL-Rlf.5(L+R)]. The relative difference of each of the ten horizontal and eight vertical variables was calculated for each individual. Using SAS software correlation coefficients were calculated for the relative asymmetry values of the monozygotic and dizygotic twin groups for each of the ten horizontal and eight vertical variables. Subsequently heritability values of craniofacial asymmetry were calculated for each of the eighteen variables using the standard formula h2= 2(rMz-rDz). The data revealed that head positioning had significantly affected our horizontal asymmetry values. We found a significant directionality in the horizontal and vertical dimension with the left side being larger horizontally and the right side being larger vertically. However the horizontal asymmetry values must be interpreted with caution as they are significantly affected by the rotation. After analyzing the data collected, the hypothesis was rejected. We were unable to demonstrate a significant difference in correlation values between monozygotic and dizygotic twins/sibling pairs for most craniofacial asymmetry values. The few variables that did show high heritability were in the horizontal plane. The results of the horizontal data must be interpreted with caution due to the significant effect of head rotation. In contrast it was found that vertical asymmetry values were not significantly correlated to rotation and none of these had notable estimates of heritability. These findings suggest that craniofacial asymmetry is more strongly influenced by environmental factors than genetics. This finding supports treatment by clinicians to improve or prevent developing asymmetries. While genetically controlled malformations can often be improved with treatment, environmentally induced malformations may respond well to treatment that changes the faulty developmental environment. Still it will be the capability of the patient to respond to the change in environment (treatment) that will determine the efficacy of the treatment. The interaction of genetic factors with this change in environment at a particular time as represented by the treatment may have a greater influence on the outcome of the treatment than how the problem was produced in the first place. Future studies analyzing asymmetry need to take extreme care in patient positioning and calibration of the x-ray machine, for they may lead to errors which overpower the data already subject to the error of a two-dimensional representation of a three dimensional object. Keeping these technical caveats in mind, future studies should focus on whether there are genetic factors that influence a patient's response (or the difference in response among patients) to the treatment of asymmetry.
Analysis of a TNFRSF11A Gene Polymorphism and External Apical Root Resorption During Orthodontic Treatment
(2005-07) French, Michael; Hartsfield, James K., Jr.; Al-Qawasmi, Riyad A.; Foroud, Tatiana M.; Roberts, W. Eugene; Shanks, James
External Apical Root Resorption (EARR) can be an undesirable side effect of orthodontic treatment. Several studies have already recognized a genetic predisposition to EARR, and some have suggested possible candidate genes that may be involved. The objective of this prospective study was to explore one possible candidate gene that may predispose individuals to EARR during orthodontic treatment. The TNFRSF11A gene encodes the receptor activator of nuclear factor-kappa β (RANK). Together with the RANK ligand, RANK mediates cell signaling that leads to osteoclastogenesis. A diallelic marker was used to investigate the possible relationship between a nonsynonymous TNFRSF11A (RANK) polymorphism and the individuals' development of EARR concurrent with orthodontic treatment. Buccal swab cells of 112 patients who had completed orthodontic treatment were collected for DNA isolation and analysis. EARR of the maxillary central incisors was calculated based on measurements from pre and post treatment occlusal radiographs. Linear regression analysis indicated that length of treatment, overjet, and molar classification are significant predictors of EARR (p=0.05). Other factors, including age, gender, and overbite, were not found to be significantly associated with EARR. An ANOVA was performed to examine the relationship of the genotyped TNFRSF11A marker with the dependent variable EARR. When individuals having at least one copy of allele 2 (1,2 and 2,3 genotypes) were pooled together, a marginally significant association was found between EARR and the marker. Further analysis using logistic regression revealed that individuals with a (1,1) genotype are 4.3 times more likely to be affected by EARR than a person with a (1,2) or (2,2) genotype. From these findings it was concluded that EARR is a complex condition influenced by several treatment variables with the TNFRSF11A gene and its product (RANK) contributing to the individuals' predisposition.
Analysis of Bone Remodeling in the Mandibular Condyle of Female Retired-Breeder Rabbits Following Altered Loading
(1992) Hunt, J. Todd; Garetto, Lawrence P.; Roberts, W. Eugene; Arbuckle, Gordon R.; Brown, David T.; Shanks, James C.
Previous studies have associated increased occlusal loads with degenerative changes of the temporomandibular joint (TMJ). The purpose of this study was to analyze effects of increased occlusal loads in adult animals. It was hypothesized that increased functional loading would cause degeneration of the mandibular condyle. Twelve female retired-breeder rabbits (mean age = three years, one month) were divided equally into three experimental groups and one control group. Each of the experimental rabbits received maxillary and mandibular light-cured anterior splints at the beginning of the study to create a bilateral posterior openbite (~2 mm). Theoretically, this should have resulted in increased loads to the TMJ. The first two groups wore the appliances for six and 12 weeks, respectively, prior to euthanasia. The third group wore the appliances for 12 weeks and then had them removed for 12 weeks prior to being euthanized. Fluorescent bone labels were utilized, and the specimens were analyzed histomorphometrically. The cartilage thickness was not statistically different between groups, nor were there any signs of cartilage degeneration. There was a trend, however, toward thinner condylar cartilage in the 12-week group. The six-week group showed significantly less labeled subchondral bone than the control group (0.5 ± 0.1 % versus 2.6 ± 0.3%, respectively; p<.05). The six- and 12-week groups both revealed significantly less periosteal surface label of the condylar neck than the control group (1.5 ± 0.8% and 5.3 ± 1. 7% versus 22.0 ± 3.5%, respectively; p<.05). Likewise, they both showed significantly more label at the cartilage-bone interface (1.0 ± 0.2% and 1.4 ± 0.2% versus 0.4 ± 0.2%, respectively; p<.05) and moderately more label along the trabecular surfaces than the control group. These results indicated that the increased loading of the mandibular condyle initially (at six weeks) depressed remodeling of the subchondral bone and decreased periosteal bone formation. Modeling increased at the cartilage-bone interface and potentially along the trabecular bone surfaces. With continued elevated occlusal loads (at 12 weeks), modeling still was quite active at the cartilage-bone interface and on the trabecular surfaces. Periosteal surface modeling remained depressed compared to the control group, but remodeling in the subchondral bone region increased to that of the control group. The 12/12-week group tended to show findings similar to the control group. This suggests that once loading was returned to normal, the condyle also returned toward preexperimental physiologic conditions. Although this study did not show the obvious degenerative changes one typically equates with osteoarthrosis, the elevated modeling at the cartilage-bone interface following increased joint loads was consistent with the early degenerative changes observed by Radin et al. in their joint-loading model. However, the rapid osseous changes seen in this study refute the theory that the adult TMJ is unable to adapt to altered functional loading.
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).
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.
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.

Browsing by Author "Roberts, W. Eugene"

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