Dentistry School Theses and Dissertations
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Item Accuracy of Guided Endodontics in Simulated Perforated Teeth with Calcified Canals(2023) Eidelstein, Dyana; Spolnik, Kenneth; Ehrlich, Ygal; Dutra, Vinicius; Hine, Charles; Warner, NedItem Are new dentists prepared for clinical practice? A survey of the clinical abilities of new dental graduates in the U.S. military(2024) Chiodo, Kathleen; Cook, N. Blaine; Capin, Oriana; Diefenderfer, Kim; Adcook, RichardObjective: This study aimed to identify new dentists’ competence in preventive and restorative procedures, as self-assessed by the new dentists and evaluated by their clinical supervisors. Justification: Preventive and restorative dental procedures constitute the majority of treatment provided daily in a general dentistry practice. Exploring new dentist proficiency in these foundational skills within one year of dental school graduation provides crucial information regarding the knowledge and skills new dentists attain during dental school. The military dental system is structured so that all new dentists receive close clinical oversight during their first year following graduation. Hypotheses: (1) The majority of dentists who have graduated less than one year prior to this survey will self-assess their skills in basic preventive and restorative dental procedures as “competent” or higher. (2) The majority of supervisor evaluations of new dentists will also average a level of “competent” or higher. (3) New dentists will self-assess their competence levels higher than their supervisors will evaluate them. Methods: An electronic, anonymous Qualtrics survey was sent to U.S. Air Force, Army and Navy new dentists and their clinical supervisors November 2022. Using a modified-Dreyfus model of skill acquisition, new dentists completed a self-assessment of 20 preventive and restorative procedures. Their clinical supervisors also completed a survey evaluating the proficiency level of the new dentists they oversaw. Results: 60 new dentists and 25 supervisors, accounting for 151 new dentists, responded. The proportion of competence ratings at a level of “competent” or higher (“proficient,” “expert”) was estimated, along with a 95% confidence interval, and one-sample chi-square tests were used to compare the proportion against 50%. Supervisors’ ratings of the new dentists’ skill levels were significantly lower than the new dentists’ ratings for 19 of the 20 dental procedures. Supervisors’ ratings of competent or higher were significantly greater than 50% in caries diagnosis and treatment planning, caries risk assessment, Class III anterior composite resins and posterior composite resins. Overall, supervisors rated 71.3% of new dentists at Novice or Beginner skill level. Conclusion: Supervisor ratings of the new dentists’ skill levels were significantly lower than the dentists’ ratings for the majority of procedures. New dentists and supervisors significantly disagreed on new dentists’ skill levels in the treatment of class I and II amalgams, endodontically treated teeth without a post, and crown preparation and delivery. Overall, 28.7% of new dentists were evaluated as competent in preventive and restorative procedures during their first year following dental school graduation.Item The Integumental Profile : A Study of Black American Children(1974) Sturrup, Randolph W.; Garner, LaForrest D.; Shafer, William G.; Shanks, James C.; Potter, Roario H.; Barton, PaulThis study was undertaken to obtain standards on soft tissue facial contour in black American children, based on an analysis of cephalometric lateral headplates. A sample of black children (10 boys and 10 girls between 10 and 14 years of age) was compared to a white sample of comparable age. The following 20 profile measurements were made and subjected to statistical analysis: Upper lip protuberance, lower lip protuberance, soft tissue profile, anterior nose length, nasal angle, naso-labial angle, upper lip inclination, lower lip inclination, esthetic plane to upper lip, esthetic plane to lower lip, mandibular sulcus, maxillary sulcus, upper lip length, upper lip to upper incisor, lower lip length, height of soft tissue chin button, point A to subnasale, upper lip thickness, and soft tissue chin button. There were significant differences between the white and black samples in all but the following five measurements: Soft tissue convexity, maxillary sulcus depth, upper lip to upper incisor, and soft tissue chin button. There were no statistically significant differences between the measurements for black males and females except that the measurement from upper lip to maxillary incisor was significantly greater in the black male. On the basis of the findings in this limited study, it appears that morphologic standards derived from one ethnic group should not be applied to individuals of another ethnic group.Item Cell Kinetic Analysis of Osteoblast Histogenesis in the Rat Mandibular Condyle Following Exposure to Hard and Soft Diets(1991) Stenftenagel, Brenda Kay; Roberts, W. Eugene; Shanks, James C.; Garetto, Lawrence P.; Hohlt, William H.; Schaaf, Jack E.Microgravity of spaceflight has been associated with inhibition of bone formation, decreased number of osteoblasts (Ob), and suppression of Ob histogenesis. This study was designed to study Ob histogenesis, i.e., the proliferation and differentiation of cells producing Ob. Inhibition of Ob formation seems to be a principal factor in osteopenia induced by spaceflight. Osteoblast histogenesis is a stress/strain mediated mechanism and appears to be gravity dependent under certain conditions. On Spacelab-3 (SL-3), the rat mandibular condyle was evaluated as a model for space study. Data indicated an increase in A+ A' cells (noncommitted and committed self-perpetuating precursor cells), and a decrease in C + D type cells (preosteoblasts that are in the G1 or G2 stage of the cell cycle), accompanied by a decrease in Obs. A stress/strain mediated increase in nuclear volume (A'=> C) is an important rate-limiting step in Ob differentiation. It is hypothesized that this step is inhibited in microgravity. Additional ground studies are needed to confirm these data and define the mechanism of action. Studies have shown that a soft diet decreases overall mechanical loading of the masticatory apparatus. A soft diet was used in this study to simulate the potential microgravity-like effects of decreased mechanical loading on the mandibular condyle, i.e., a decreased masticatory force was used as a model for microgravity. Eighteen male, Sprague-Dawley rats (six to eight weeks of age) were divided into three groups: 1) the experimental group maintained on a soft paste diet; 2) a control group, pair fed equal amounts of food as the experimental group; and 3) a control group fed ad libitum. Both control groups were fed standard Purina TM Rat Chow (sPRC) pellets. The experimental diet consisted of sPRC, crushed and mixed with sufficient water to form a paste. After two weeks on their respective diets, each animal was injected i.p. with xylenol orange, a bone label. One week later calcein green was administered similarly. Two days after the last label, animals were injected i.p. with 3H-thymidine at 8 a.m. One hour later each animal was anesthesized with ketamine and decapitated. Mandibles were fixed for 72 hours. Nuclear morphometry and labeling index data were collected from autoradiographs prepared from demineralized sections. Due to technique problems, only three paste group condyles and five condyles from each of the control groups could be examined. Results showed no significant differences at p < 0.05 in labeling index. Nuclear morphometry data indicated a significant difference in L, A+ A', C, and C + D cells. Rats fed a paste diet had on the average 12 percent more type A+ A' cells, and 17-25 percent less C + D combined cells than the two control groups. These data indicate a similar shift in Ob histogenesis to the left (more A + A' cells) as that found in the POL and the condyle of rats flown in space. These findings support the hypothesis that osteopenia induced in spaceflight may be the result of a reduction in a local mechanical component, or a lack of anti-gravity posturing. Therefore, it may be concluded that a soft paste diet mimics microgravity by decreasing mechanical loading and inhibiting the stress/strain mediated increase in nuclear volume (A'=> C). The condyle from rats fed a soft diet may be a valuable model for studying osteopenia.Item Evaluation of IL-1 B (+3954) Gene Polymorphism and External Apical Root Resporption Associated with Orthodontic Treatment(2005) Smith, Elizabeth Dockerty; Hartsfield, James K., Jr.; Al-Qawasmi, Riyad A.; Foroud, Tatiana M.; Roberts, W. Eugene; Shanks, JamesThe purpose of this prospective study was to examine the external apical root resorption (EARR) status and genetic marker composition of 100 Caucasian patients (59 females and 41 males) who have undergone orthodontic treatment at the private practice office of Dr. James V. Macri. A diallelic polymorphism marker for IL-1B +3954 within the candidate gene IL-1B was used to investigate the difference in relative risk for EARR. EARR measurements taken on pre and post treatment occlusal radiographs were then used to determine any association with genotype. Using linear regression analysis, length of treatment, overjet and molar classification were found to be significant predictors of EARR (p<0.05). The findings indicated that increased length of treatment or overjet is associated with increased EARR. Furthermore, those subjects with a class II molar classification were less likely to experience EARR compared to those with either a class I or class III molar classification. An ANOV A test was performed to examine the relationship of the IL-1B marker with the dependent variable EARR. There was no statistically significant association between the IL-1B genotype and EARR (p=0.53). Finally, a chi-square test was used to evaluate the association of the IL-1B genotypes in the affected (>5mm EARR) and unaffected (<5mm EARR) groups. There was no significant association between affection status and the IL-1B genotype (p=0.87).Item 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.Item Cephalometric Study of Human Mandibular Proportions and Relationships in Normal Occlusion(1947) Stoner, Morris M.Item A Cephalometric Study of Velar Height as a Function of Voice Fundamental Frequency in the Normal Speaker(1975) Simons, Charles MorrisAn understanding of velar activity during vowel utterance has resulted from the use of several methods of study and observation. Both acoustic and perceptual methods have been used to describe velar activity. Acoustic characteristics have been related to nasality. Perceptual studies have enumerated variation in judged severity of nasality. Cinefluorographic techniques have been used to investigate the effects of vocal effort and fundamental frequency on velar movement. Intra-oral photographic techniques have also been employed to understand this relationship. Due to conflicting reports from the several techniques, the present study was undertaken to utilize a new approach of still cephalometric radiographs during sound production. The purpose of the present study was to use a cephalometric procedure to investigate velar height and velopharyngeal gap as a function of fundamental frequency in normal subjects. Four levels of fundamental frequency (10%, 25%, 50%, and 75% of the subject's total vocal range) at constant vocal effort were performed by 11 normal adult males on sequences of the vowel /a/. Each subject was carefully trained to utter the vowel sound at each of the four pitch levels as computed by a Honeywell Visicorder. A v-u meter indicated constancy of vocal effort. A lateral cephalometric headplate was taken under each of the four vocal pitch conditions. Velar height and velopharyngeal gap were measured by means of an acetate tracing from each headplate. The measurements were submitted for statistical interpretation. Major findings included: 1. Tracings and measurements could be done accurately. 2. Vocal fundamental frequency productions were accurate. 3. Vocal effort could be maintained constant. 4. No significant difference between pitch levels for either velar height or velopharyngeal gap was indicated. 5. Highly significant differences in measurements of velar height and velopharyngeal gap were noted between subjects. 6. No significant correlation between 75% and 10% pitch levels was indicated by a Pearson product-moment correlation. 7. A significant correlation between 25%, 50% and 75% levels was evidenced.Item A Cephalometric Appraisal of Dentofacial Changes Following the Insertion of Artificial Dentures(1955) Starr, Richard; Muhler, Joseph; Phillips, RalphItem Treatment of Enamel Demineralization Following Orthodontic Therapy(1997) Stoll, Lana R.; Garetto, Lawrence P.; Analoui, Mostafa; Dunipace, Ann J.; Hohlt, William F.; Schemehorn, Bruce R.; Shanks, JamesThe early-stage, carious, white-spot lesion is a common finding on teeth in patients who have received orthodontic treatment. Recently, a calciumphosphate (Ca-P) treatment was developed to enhance remineralization of white spot lesions. We hypothesized that a rinse containing the Ca-P would promote greater remineralization of demineralized enamel in vivo than a fluoride (F)-containing rinse or a placebo rinse. Thirty post-treatment orthodontic patients with demineralized white spot lesions on one or more of the six maxillary anterior teeth were selected and randomly assigned to three equal groups for a double-blind study. One group was given the placebo rinse. Another group was given a rinse with the same ingredients as the placebo rinse plus 0.055% F. The third group was given a rinse with the same ingredients as the F rinse plus calcium, phosphate, and magnesium salts. In addition, all subjects used a 0.011% F dentifrice before rinsing. Two different methods were used to determine the initial extent and subsequent de- or remineralization of the white spot lesions at the debonding appointment (baseline), and at one, three, and six months after the baseline reading: 1) visual inspection, in which two examiners estimated the severity and location of the lesions, and 2) quantitative laser fluorescence (QLF), in which the depth and area of the lesions were determined more objectively. Lnterexaminer agreement was almost perfect for the clinical exams. All three groups were significantly different with regards to reduction of number of white spots according to the clinical scoring. The placebo rinse group had the greatest reduction followed by the Ca-P group and the fluoride group. The QLF data showed no significant overall group differences for any of the measurements except total lesion depth. The placebo group had a significantly greater reduction of total lesion depth at the last examination than the Ca-P group (p < 0.05). The data suggested that different mechanisms may exist for remineralization of large and small lesions and that remineralization of a lesion with a lower concentration of fluoride, such as that used with the placebo rinse and the fluoride dentifrice, may result in greater remineralization of white-spot lesions.