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Veneering composites for dental indirect restorations: a comparative study of physical and mechancial properties
2003 (English)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

The purpose of this study was to identify the microstructure and to compare mechanical and physical properties, wear properties and aging properties of ten commercial dental products for indirect dental restorations: belleGlass (KerrLab), Enamel Plus (GDF), Cristobal+ (Dentsply Ceramco), Targis (Ivoclar Vivadent), Dialog (Schütz-Dental), Adoro (Ivoclar Vivadent), Gradia (GC), Signum+ (Heraeus Kulzer), Solidex (Shofu), Sinfony (ESPE). The uniqueness of this study is the large number of commercial products investigated under the same testing conditions and that all ten materials are cured using the specific curing unit recommended by each manufacturer. This made it possible to carry out accurate comparisons of the different materials and to classify their performance in each test. Due to the advantage of the large number of materials, many correlations could be established between filler types, curing techniques and physical and mechanical properties. Based upon the identification of the microstructures of the materials, four different groups could be distinguished: 1) highly filled micro hybrids (belleGlass, Enamel Plus, Cristobal+ and Targis): 2) micro hybrids with prepolymers (Dialog, Gradia, Solidex): 3) microfilled materials (Adoro and Signum+): and 4) micro hybrids without prepolymers (Sinfony). Mechanical properties such as flexural strength, modulus of elasticity, fracture toughness, hardness and diametral tensile strength were determined and evaluated using one-way ANOVA and Tukey’s post hoc tests (p<0.05). it was observed that highly filled micro hybrids performed very well in basically all mechanical tests and that the least filled material (sinfony) showed very low mechanical properties. good correlations were found between filler content and most of the mechanical test results. however, in terms of other properties (chemical, physical or mechano-chemical properties) such as discolouration and wear, the microfilled (adoro and signum+) materials showed the best results due to their good surface properties and inert filler particles. the wear test also revealed that the higher filled micro hybrids did generally not perform very well in this wear simulation mostly due to higher surface roughness and filler particle leaching caused by the water that was present throughout the wear test. as a part of the study of long-time performance of the materials, aging tests were carried out and different aging media were evaluated for optimal aging simulations. mechanical properties as well as surface evaluations of the materials were performed in three different aging media (boling naf, ultraviolet light exposure and a 75% ethanol-water solution at 37°c) in order to investigate the chemical degradation of the materials. the greatest influence on the mechanical properties was caused by the ethanol solution. after aging in the boiling naf solution great particle losses were observed in basically all glass filled materials while the microfilled materials showed an almost unaffected surface structure after aging. another interesting result from the aging simulations was that the light-cured-only materials experienced further polymerisation due to high temperatures and/or high-intensity light during aging, indicating that their curing procedures do not lead to fully polymerised materials. according to the findings of this study, there does not exist any one material that performs well in all the different tests. the microstructure and filler content are fundamental in the explanation of the different behaviours, and depending on which material property is considered to be clinically most important, different classifications and rankings can be made. the ranking of the materials made in this report was based on the general opinions of dentists, dental technicians, dental material scientists and the conclusion revealed that microfilled materials showed the best overall performance and that out of the microfilled materials, adoro was the best performing.

Place, publisher, year, edition, pages
2003.
Keyword [en]
Technology, dental materials, composites, indirect restorations, aging, mechanical properties, physical properties
Keyword [sv]
Teknik
Identifiers
URN: urn:nbn:se:ltu:diva-59346ISRN: LTU-EX--03/277--SELocal ID: fe1a5466-9381-4902-928d-ed383ce02425OAI: oai:DiVA.org:ltu-59346DiVA: diva2:1032733
Subject / course
Student thesis, at least 30 credits
Educational program
Materials Engineering, master's level
Examiners
Note
Validerat; 20101217 (root)Available from: 2016-10-04 Created: 2016-10-04Bibliographically approved

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