Student Research

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    The Effect of the Kalirin Gene on Osteoid Development
    (2020) Holland, R.; Hong, J.M.; Bruzzaniti, Angela
    Lrp5 Gene Over-expression Leads to Decreased Tooth Movement. R. Holland*, C. Bain, A. Robling, A. Utreja. (Indiana University School of Dentistry) Lrp5 (Low-density lipoprotein receptor-related protein 5) is a co-receptor of the Wnt intracellular signaling system. The Wnt system is known to play an important role in bone biology. Increased activity of the Wnt system leads to an increase in bone mass. The aim of this study was to compare tooth movement in genetically modified Lrp5 knock-in mice to control mice. Thirty-six C57BL/6 wildtype mice were utilized. Eighteen possessed a A214V mutation and eighteen possessed a G171V mutation in the Lrp5 gene. Eighteen wild type C57BL/6 mice served as control. Experimental tooth movement was produced by attaching a 3mm closed-coil nickel-titanium spring from the first molar to the incisors. Tooth movement occurred for three weeks prior to sacrifice. For all but six mice, a microchromotagraphy scan was taken after sacrifice followed by a histologic analysis. The remaining six mice were Mice were injected with Calcin, Alizeren and Tetracycline at eight, four and two days pre-sacrifice respectively. These mice were processed in plastic and analyzed with fluorescent microscopy. Genetic knock-in mice showed higher percent bone volume (BV/TV), lower bone surface/volume ratio (BS/BV) and increased trabecular thickness (Tb.Th) compared to the control group. Cellular expression of the Sclerostin gene was higher per unit area in the genetic knock-in mice compared to the control mice. Fluorescent microscopy showed decrease in bone turnover in the genetic knock-in mice compared to the control. This study demonstrates that overexpression of the Lrp5 gene leads to an increased bone density, decreased bone turnover and a decreased rate of tooth movement in mice. Further study should be completed on the Wnt signaling pathway as this could lead to improvement of future orthodontic treatments.
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    Longevity of Crown Margin Repair Using Glass Ionomer: A Retrospective Study
    (International Association for Dental Research, 2020) Watson, Justin; Tang, Qing; Patel, Jay; Diefenderfer, Kim E.; Thyvalikakath, Thankam; Cook, N. Blaine
    Objectives: Repair of crown margins may extend the functional life of existing crowns. However, the longevity of such treatment is unknown. This study determined the survival time of crown margin repairs (CMR) with glass-ionomer (GI) and resin-modified glass-ionomer cements. Methods: We queried axiUm (Exan Group, Coquitlam, BC, Canada) database for permanent teeth that underwent CMR in the Graduate Operative Dentistry Clinic, Indiana University School of Dentistry (IUSD), Indianapolis, Ind., USA, from January 1, 2006 through January 1, 2018. Since there is no CDT code for the CMR procedure, CDT codes for resin-composite and GI restorations (D23XX) were queried; these patients also had treatment notes that indicated CMR. The final data set included patient ID, birth date, gender, dates of treatments, CDT codes, tooth type, tooth surface and existing findings. Two examiners developed guidelines for record review and manually reviewed the clinical notes of patient records to confirm CMR. Only records that were confirmed with the presence of CMR were retained in the final dataset for survival analysis. Survival time was calculated by Kaplan-Meier statistics and a Cox Proportional Hazards model was performed to assess the influence of selected variables (p < 0.05). Results: 214 teeth (115 patients) with CMR were evaluated. Patient average age was 69.4  11.7 years old. Posterior teeth accounted for 78.5 percent (n = 168) of teeth treated. CMRs using GI had a projected 5-year survival rate of 62.9 percent (K-M Analysis) and an 8.9 percent annual failure rate. Cox Proportional Hazards Regression analysis revealed that none of the factors examined (age, gender, tooth type) affected time to failure. Conclusion: CMRs may extend the longevity of crowns with defective margins. Larger EHR studies or case control studies are needed to investigate other variables, such as the caries risk status or the severity of defects that may affect the survival rate of CMR.
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    Using Asynchronous, Limited-facilitation Case-based Exercises to Enhance Dental Student Learning
    (2020) Scully, A.
    Case-based learning strategies have been used in education for decades. Studies suggest case-based learning can promote a deeper understanding of material and better retention. However, traditional case-based learning has several disadvantages including increased faculty time requirements and student scheduling challenges. Objectives: The aim of this study is to assess if asynchronous, limited-facilitation cases are a potentially viable method to enhance dental students’ perceived understanding of pediatric dentistry. Methods: 9 novel, distinct clinical cases were created to cover integrated topics including anatomy, physiology, pharmacology, cariology, diagnosis and treatment planning for the pediatric patient. Students enrolled in the pediatric dental clinic were required to take a survey consisting of Likert scale questions prior to completing each case and immediately after the case. The cases were completed during clinic rotations in pediatric dentistry, either alone or in small groups, in PowerPoint slideshow mode. Faculty provided guidance when questions arose. The baseline and immediate post-survey results were summarized and Wilcoxon rank sum tests were used to compare matching questions with a 5% significance level. Results: 120 third year dental students and 109 fourth year dental students participated in at least one case exercise. Baseline survey results showed that the average confidence of the students generally ranged between a 3.5 and a 4.0 on a 5 point scale, although the range of averages was between 2.3 and 4.3 depending on the subject of the question. The Wilcoxon rank sum tests showed that for 58 of the 62 questions there was a statistically significant increase from the baseline survey to the immediate post-exercise survey. 6-month post survey data results are pending. Conclusion: Asynchronous, non-facilitated cases may be beneficial as an adjunct to dental student perceived understanding of integrated dental concepts.