Faculty Publications - Faculty of Dentistry
Permanent URI for this collectionhttps://hdl.handle.net/1807/90867
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Item Artificial Enamel Wear after Prolonged Chewing Simulation against Monolithic Y-TZP Crowns(2018) Vedana, Deborah; Vedana, Leonardo; Martins, Emerson Alves; Brodersen, Peter; De Souza, Grace M.Item Effect of tooth whitening strips on fatigue resistance and flexural strength of bovine dentin in vitro(2017) Tam, Laura E; Kim, Namhee; De Souza, Grace MTo determine the effects of whitening strips on bovine dentin fatigue resistance and flexural strength in vitro.Item Matrix metalloproteinase inhibitor modulates esterase-catalyzed degradation of resin-dentin interfaces(2016) Serkies, Kyle B; Garcha, Reena; Tam, Laura E; De Souza, Grace M; Finer, YoavAssess the modulating effect of matrix metalloproteinase (MMP) inhibition on simulated human salivary enzyme (SHSE)-catalyzed degradation of interfacial fracture-toughness (FT) of self-etched and total-etched resin-dentin interfaces.Item Different Strategies to Bond Bis-GMA-based Resin Cement to Zirconia(2016) Lopes, Guilherme Carpena; Spohr, Ana Maria; De Souza, Grace MTo evaluate the effect of different bonding strategies on short- and long-term bis-GMA-based resin cement bond strengths to zirconia.Item Fracture Strength of Aged Monolithic and Bilayer Zirconia-Based Crowns(2015) Lameira, Deborah Pacheco; Buarque e Silva, Wilkens Aurélio; Andrade e Silva, Frederico; De Souza, Grace MThe purpose of this study was to evaluate the effect of design and surface finishing on fracture strength of yttria-tetragonal zirconia polycrystal (Y-TZP) crowns in monolithic (1.5 mm thickness) and bilayer (0.8 mm zirconia coping and 0.7 mm porcelain veneer) configuration after artificial aging. Bovine incisors received crown preparation and Y-TZP crowns were manufactured using CAD/CAM technique, according to the following groups (n = 10): Polished monolithic zirconia crowns (PM); Glazed monolithic zirconia crowns (GM); Bi-layer crowns (BL). Crowns were cemented with resin cement, submitted to artificial aging in a chewing simulator (2.5 million cycles/80 N/artificial saliva/37 °C), and tested for fracture strength. Two remaining crowns referring to PM and GM groups were submitted to a chemical composition analysis to measure the level of yttrium after aging. One-way ANOVA and Tukey's test (P = .05) indicated that monolithic zirconia crowns presented similar fracture strength (PM = 3476.2 N ± 791.7; GM = 3561.5 N ± 991.6), which was higher than bilayer crowns (2060.4 N ± 810.6). There was no difference in the yttrium content among the three surfaces evaluated in the monolithic crowns. Thus, monolithic zirconia crowns present higher fracture strength than bilayer veneered zirconia after artificial aging and surface finishing does not affect their fracture strength.Item Correlation between clinical performance and degree of conversion of resin cements: a literature review(2015) De Souza, Grace; Braga, Roberto Ruggiero; Cesar, Paulo Francisco; Lopes, Guilherme CarpenaResin-based cements have been frequently employed in clinical practice to lute indirect restorations. However, there are numerous factors that may compromise the clinical performance of those cements. The aim of this literature review is to present and discuss some of the clinical factors that may affect the performance of current resin-based luting systems. Resin cements may have three different curing mechanisms: chemical curing, photo curing or a combination of both. Chemically cured systems are recommended to be used under opaque or thick restorations, due to the reduced access of the light. Photo-cured cements are mainly indicated for translucent veneers, due to the possibility of light transmission through the restoration. Dual-cured are more versatile systems and, theoretically, can be used in either situation, since the presence of both curing mechanisms might guarantee a high degree of conversion (DC) under every condition. However, it has been demonstrated that clinical procedures and characteristics of the materials may have many different implications in the DC of currently available resin cements, affecting their mechanical properties, bond strength to the substrate and the esthetic results of the restoration. Factors such as curing mechanism, choice of adhesive system, indirect restorative material and light-curing device may affect the degree of conversion of the cement and, therefore, have an effect on the clinical performance of resin-based cements. Specific measures are to be taken to ensure a higher DC of the luting system to be used.Item Effect of Training Method on Dental Students' Light-Curing Performance(2018-08) De Souza, Grace M; El-Badrawy, Wafa; Tam, Laura EThe aims of this study were to evaluate 1) the effect of different light-curing training methods on first-year dental students' light-curing performance immediately after and one year after training and 2) the effect of dental student year (first vs. third year) and different light-curing training methods on students' light-curing efficacy. The study was organized into two parts, conducted in 2013 and 2014. In the first part, all students (N=66) in the first-year restorative course at a Canadian dental school were invited to participate in a light-curing activity immediately after training; after 12 months, those students (now in their second year) were asked to again perform the light-curing activity. In the second part, all the subsequent first-year students (N=75) and third-year students (N=95) were invited to perform the same light-curing activity after training. Each class was divided into three groups: the Control group received a lecture; the Tips group received the same lecture plus tips on "7 Steps to Ensure Better Light Curing"; and the Simulator group received the lecture, tips, and hands-on training using the patient simulator. In the first part of the study, all 66 students participated in the first year; 39 of those participated a year later. In the second part, all students in both years participated. For the first part, time had a significant effect on light-curing performance, with significantly higher results in the second year. When the first-year students' results were isolated, training method had a significant effect on mean and maximum irradiance values. The second part found a significant effect of training on mean (p=0.003) and maximum (p=0.021) irradiance. The interaction DDS*training was significant (p=0.037) when the after-training values were analyzed. These results point to the need for further research to determine the most effective light-curing training methods.Item The Role of a MDP/VBATDT-Primer Composition on Resin Bonding to Zirconia(2018) Aggarwal, Anuj; De Souza, Grace