Browsing by Author "Scully, A."

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    Mechanical property evaluation of porous 13-93 Bioactive Glass and GL1550 Borate Glass 3D scaffolds
    (Office of the Vice Chancellor for Research, 2013-04-05) Li, D.; Scully, A.; Chu, Tien-Min Gabriel
    Reconstructing large craniofacial defects is clinically challenging and current engineered scaffolds are inadequate in either mechanical or biologic properties. Borate bioactive-glass (BBG) is a promising material for scaffolds due to its higher solubility compared to traditional 13-93 bioactive glass. The main objective of the research is to compare the mechanical properties (σfailure, Pb) of scaffolds made from 13-93 bioactive-glass (A) and GL1550 borate bioactive-glass (B) powders, at different sintering temperatures, and with/without polymer coatings. In this paper, dense scaffolds are made via dry-pressing while porous scaffolds are made via a sol casting method using polymers to promote porosity (d=6mm, t=3-4mm). All the scaffolds were sintered in a tube furnace. The temperature increased 10˚C/min until reaching the sintering temperature which varied from 500oC and 700oC. All the samples were cooled in the furnace. The mechanical properties were measured using a diametral test on a Universal Testing Machine (MTS Sintech Renew, Model 1123, Minnesota, USA). For each group and temperature, at least 3 samples were tested. The mechanical properties (σfailure, Pb) of scaffolds made from 13-93 bioactive-glass and GL1550 bioactive-glass powders are compared. Samples are then coated with 1% or 5% PLLA. Effects of porosity, sintering temperature, and polymer coating are related to mechanical properties to find the optimal heat treatment procedures and polymer concentration. Balanced with the porosity, the optimal sintering temperature was set to be 540˚C for GL1550 bioactive-glass powder and 690˚C for 13-93 bioactive glass. At the optimal sintering temperature, Pb=14.516±2.075N, σf=0.487±0.036MPa for borate glass scaffold with ~67% porosity, and Pb=36.725±5.786N, σf=1.280±0.276MPa for 13-93 bioactive glass scaffold with ~50% porosity. The 5% coating of PLLA offers a good balance between maintaining a high level of porosity and mechanical property improvement. The processing conditions will be used for their future in vivo evaluations.
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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.