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Impact of in-vitro aging on mechanical and optical properties of veneering composites


Egli, R E. Impact of in-vitro aging on mechanical and optical properties of veneering composites. 2010, University of Zurich, Faculty of Medicine.

Abstract

State of Problem: Flexural strength, hardness, surface roughness, discoloration and abrasion stability are important properties of veneering composites. The second-generation of veneering composite systems are said to have enhanced mechanical properties due to their composition. Purpose of study: This study tested and compared the impact of aging on three different veneering composites. Material and methods: Indirect composites: GC Gradia, VITA VM LC and Sinfony, were prepared for flexural strength (N=495; n=165 per composite), Martens hardness (N=30, n=10 per composite), surface roughness (N=30, n=10 per composite), discoloration measurement (N=90, n=30 per composite) and abrasion stability (N=18, n=6 per composite). After the initial flexural strength was measured, half of all remaining specimens were stored in water and the other half was subjected to thermocycling for 1, 7, 28, 90 or 180 days. Hardness and surface roughness (water stored: n=5 of each composite und thermocycling: n=5 of each composite) were tested before and after 1, 7, 28, 90, and 180 days aging. The discoloration specimens were randomly divided in three groups (coffee: n=10 per composite, black tea: n=10 per composite and red wine: n=10 per composite), aged and discoloration was measured. Abrasion stability was determined after 120 000, 240 000, 640 000 and 1 200 000 cycles in the chewing simulator. Data were analyzed with one-way ANOVA followed by a post-hoc Scheffé test and t-test. The longitudinal observations were analysed using linear mixed models (alpha=0.05). Results: In summary, when considering all 10 tested different properties Sinfony revealed the best results (5 positive assessements) followed by GC Gradia (2 positive, 1 negative) and VITA VM LC (2 positive, 3 negative). Conclusion: The veneering composite Sinfony showed the most stable tested properties.

Abstract

State of Problem: Flexural strength, hardness, surface roughness, discoloration and abrasion stability are important properties of veneering composites. The second-generation of veneering composite systems are said to have enhanced mechanical properties due to their composition. Purpose of study: This study tested and compared the impact of aging on three different veneering composites. Material and methods: Indirect composites: GC Gradia, VITA VM LC and Sinfony, were prepared for flexural strength (N=495; n=165 per composite), Martens hardness (N=30, n=10 per composite), surface roughness (N=30, n=10 per composite), discoloration measurement (N=90, n=30 per composite) and abrasion stability (N=18, n=6 per composite). After the initial flexural strength was measured, half of all remaining specimens were stored in water and the other half was subjected to thermocycling for 1, 7, 28, 90 or 180 days. Hardness and surface roughness (water stored: n=5 of each composite und thermocycling: n=5 of each composite) were tested before and after 1, 7, 28, 90, and 180 days aging. The discoloration specimens were randomly divided in three groups (coffee: n=10 per composite, black tea: n=10 per composite and red wine: n=10 per composite), aged and discoloration was measured. Abrasion stability was determined after 120 000, 240 000, 640 000 and 1 200 000 cycles in the chewing simulator. Data were analyzed with one-way ANOVA followed by a post-hoc Scheffé test and t-test. The longitudinal observations were analysed using linear mixed models (alpha=0.05). Results: In summary, when considering all 10 tested different properties Sinfony revealed the best results (5 positive assessements) followed by GC Gradia (2 positive, 1 negative) and VITA VM LC (2 positive, 3 negative). Conclusion: The veneering composite Sinfony showed the most stable tested properties.

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Additional indexing

Item Type:Dissertation
Referees:Hämmerle C H F
Communities & Collections:04 Faculty of Medicine > Center for Dental Medicine > Clinic for Fixed and Removable Prosthodontics
Dewey Decimal Classification:610 Medicine & health
Language:English
Date:2010
Deposited On:22 Jan 2011 18:55
Last Modified:26 Jan 2017 08:48
Number of Pages:39

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