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Unless otherwise noted, the content of this course material is licensed under a Creative Commons Attribution 3.0 License. Copyright 2008, Dr. Stephen Bayne.

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Presentation on theme: "Unless otherwise noted, the content of this course material is licensed under a Creative Commons Attribution 3.0 License. Copyright 2008, Dr. Stephen Bayne."— Presentation transcript:

1 Unless otherwise noted, the content of this course material is licensed under a Creative Commons Attribution 3.0 License. Copyright 2008, Dr. Stephen Bayne. The following information is intended to inform and educate and is not a tool for self-diagnosis or a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional. You should speak to your physician or make an appointment to be seen if you have questions or concerns about this information or your medical condition. You assume all responsibility for use and potential liability associated with any use of the material. Material contains copyrighted content, used in accordance with U.S. law. Copyright holders of content included in this material should contact open.michigan@umich.edu with any questions, corrections, or clarifications regarding the use of content. The Regents of the University of Michigan do not license the use of third party content posted to this site unless such a license is specifically granted in connection with particular content objects. Users of content are responsible for their compliance with applicable law. See http://www.dent.umich.edu/license/ for more information. http://www.dent.umich.edu/license/ Mention of specific products in this recording solely represents the opinion of the speaker and does not represent an endorsement by the University of Michigan. Viewer discretion advised: Material may contain medical images that may be disturbing to some viewers.

2 LABORATORYWAXES Stephen C. Bayne University of Michigan School of Dentistry Ann Arbor, Michigan sbayne@umich.edu

3 OVERVIEW OF DENTAL WAXES 1.Definition of dental wax = thermoplastic molding material that is solid at room temperature. 2.General Composition of Waxes: a.BASE Wax: (1) Hydrocarbon [eg, PARAFFIN] or ester types; (2) High or low MW b.MODIFIER Waxes: (1) Hydrocarbon or ester types; (2) High or low MW c.COLORANT:

4 BASE AND MODIFIER WAXES Name:Origin:Composition:Melting (  C) Density (20  C) PARAFFINMineralHydrocarbon mixture50-570.90 CERESINMineralComplex hydrocarbons61-780.91-0.92 BEESWAXAnimalEster mixture62-650.95-0.96 CANDELILLAPlantC 21 hydrocarbons68-700.95-0.99 CARNAUBAPlantHydrocarbon, Ester, Fatty Acid82-860.99-0.999 GUM DAMMARPlantAromatic resinca 1201.040-1.120 ROSINPlantAromatic resin acid100-1501.08 INLAY WAX = Paraffin + Carnuba + Ceresin + Beeswax + Colorants

5 CLASSIFICATION OF DENTAL WAXES

6 INLAY WAX 1.Overview: a.Objective: Pattern material to accurately represent desired mold space for inlays, onlays, and crowns. b.Requirements for Inlay Waxes: (1)Good adaptation to dies (2)Thermal stability at low temperatures (3)Complete pyrolysis at high temperatures 2.Inlay Wax Composition: a.60% Paraffin Wax= BASE Wax b.25% Carnuba Wax= MODIFIER Wax c.10% Ceresin= MODIFIER Wax d. 5% Beeswax= MODIFIER Wax e.<1% Colorants= COLORANT

7 COMPOSITION (%) TEMPERATURE (C) ParaffinCarnuba 40 30 20 60 50 70 80 90 255075100 LIQUID LIQUID + SOLID SOLID Melting Onset (Solidus) Melting Completion (Liquidus) INLAY WAX Physical Properties – Melting Range Image and graph source: Steve Bayne, University of Michigan, 2008

8 250 ppm/  C Paraffin Carnuba Beeswax 0253040453550 0 1.2 1.0 0.8 0.6 0.4 0.2 TEMPERATURE (C) EXPANSION (%) KERR HARD WAX INLAY WAX Physical Properties – Thermal Expansion of Components Graph source: Steve Bayne, University of Michigan, 2008

9 Mechanical Properties:  Flow < 1%  Ductility = moderate  Residual Stress = none INLAY WAX Mechanical Properties and Chemical Properties Chemical Properties:  Homogeneity = good  Contact Angle = low  Oxidation = complete

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