Browsing by Author "Hathaway, Ronald"

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    Assessment of Dental Asymmetry Utilizing Orthodontic Study Casts Comparing Tooth Positions to the Midpalatal Raphe and Tooth Size Among Antimeres
    (2002) Sprowls, Matthew W.; Hartsfield, James K., Jr.; Baldwin, James; Everett, Eric T.; Hathaway, Ronald; Shanks, James C.; Ward, Richard E.
    Several studies have been conducted in relation to the treatment and etiologies of craniofacial and dental asymmetries in the orthodontic scientific literature. However, limited research has attempted to correlate asymmetry in dental traits to each other. The purpose of this research study was to develop a better understanding of the correlations between dental arch asymmetry and dental tooth size asymmetry and their underlying causes. Understanding asymmetries is essential in orthodontic diagnosis and treatment planning. An orthodontist cannot obtain an optimal occlusal and functional result without properly balancing skeletal and dental relationships. Pretreatment dental study casts of 86 sequential patients from the postgraduate orthodontic clinic at the Indiana University School of Dentistry were used for the analysis. Each patient was analyzed in a single blind fashion to minimize bias. The Adobe Photoshop® ruler and Chicago® brand electronic digital calipers accurate to the nearest tenth of a millimeter were used for digital measurements. Measurements were made to determine the amount and direction of asymmetry along the dental midlines relative to the median palatine raphe. Transverse and sagittal measurements were made to record asymmetries in canine and molar positioning. Furthermore, three sets of antimeric maxillary teeth were measured for length and width. These included the central incisors, the canines, and the first molars. Fluctuating asymmetry was present in all measurements, except molar distance to median palatal raphe. This was found to be directional to the left in the entire sample group. Statistical analysis was subsequently performed and the results showed significant correlations in the individuals in the subsample dentition group. Subjects belonging to this group with a measurable degree of fluctuating asymmetry had a greater tendency toward transverse maxillary discrepancies as measured from the canines and first maxillary molars relative to the median palatal raphe. Moreover, individuals in the subsample group with above average total weighted fluctuating asymmetry values according to the parameters analyzed in this study appeared more likely to have decreased developmental stability leading to the clinical expression of more severe malocclusions.
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    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.
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    The Effect of Nicotine on Human Lymphocyte IL-6 Production
    (2001) Zhang, Shaobin; Olson, Byron L.; Gregory, Richard L.; Hathaway, Ronald; Shanks, James; Katona, Thomas
    Studies have suggested that the immune system may play important roles in the regulation of bone remodeling through cytokines secreted by inflammatory cells migrating from periodontal ligament capillaries after orthodontic force application. There is evidence that tobacco usage has profound effects on bone metabolism. The mechanism of nicotine on bone metabolism is not fully understood. One possibility may be related to certain cytokines. Cytokines are hormone-like molecules. They are important in regulating the development of the immune system and mediating immune responses. Interleukin 6 is an important cytokine secreted by activated T cells. IL-6 is a multifunctional interleukin with significant effects on different cell types. IL-6 can regulate the development and function of osteoblasts and osteoclasts, and thus play important roles in bone remodeling during orthodontic tooth movement. Nicotine is the major pharmacological component of tobacco. It can exert effects directly on lymphocytes by signaling through nicotinic acetylcholine receptors. Nicotine has profound effects on cytokine production in the immune system. The effect of nicotine on T cell IL-6 production may have an important impact on bone remodeling. However, the effects of nicotine on human T cell IL-6 production have not been extensively studied. The purpose of this study was to determine whether nicotine affects T cell proliferation and IL-6 production by activated T cells. Also the effect of nicotine on T cell activation was studied. The H9 cell line derived from a human cutaneous T cell lymphoma was used as the human T cells in this study. 2x106/ml T cells cultured with different mitogens were stimulated with nicotine for 24, 48, and 72 hr. The chosen nicotine concentrations were 0; 1; 10; 100; 1,000; 3,000; and 10,000 ug/ml. The effects of nicotine on T cell proliferation, T cell metabolic activity, and IL-6 production were studied. Also, the effects of different mitogens on T cell activation were studied. The results demonstrated that high concentrations of nicotine (1,000; 3,000; and 10,000 ug/ml) significantly decreased T cell proliferation, T cell metabolic activity, and IL-6 production. A medium concentration of nicotine (100 ug/ml) slightly increased IL-6 production. This study also demonstrated that TP A is essential in induction of IL-6 from activated T cells. PHA has synergistic effects on TPA induced IL-6 production. ConA, PHA, PHA+ IL β and nicotine did not induce IL-6 production from T cells. Signal transduction is probably involved in this complex process. The results of this study suggested that nicotine has adverse effects on T cell functions.