: Ralf Janda
: Advanced Level of Dental Resins - Material Science& Technology 2nd Edtion / 2nd Version
: Tredition
: 9783347382237
: & Technology
: 1
: CHF 11.60
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: Zahnheilkunde
: English
: 748
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: PC/MAC/eReader/Tablet
: ePUB
Resin materials are broadly used in dentistry for almost all indications, and they will gain even more importance in the future. Especially, the increasing performance and efficiency of the CAD/CAM technology and 3D-printing open possibilities to use resins not used up to now in dentistry. Besides dentists, dental students or dental technicians, there are many other specialists such as researchers, material scientists, industrial developers or experts of adjoining professional disciplines who are technically engaged in dental resins. The idea of this e-Book series is to present a three-level textbook consisting of 'Basic Level', 'Advanced Level' and 'Expert Level' versions dealing with material science and technology of dental resins. Every level significantly expands the information and knowledge given by the respective preceding version. This book presents the 'Advanced Level' version. The 'Advanced Level' broadens the information given in the 'Basic Level' significantly and mainly addresses teachers of dental universities/schools, postgraduate students, PhD candidates, researchers, material scientists, industrial developers or experts of adjoining professional disciplines. The 'Advanced Level' gives a very profound insight into chemistry, physics, testing methods and toxicology of dental resins and their technical application.

Ralf Janda was born in 1953 in Berlin. He obtained his Abitur (secondary school-leaving examination in 1973 and pursued chemistry at the Free University Berlin (FUB) from 1973 to 1978, thereby obtaining the degree Diploma-Chemist (summa cum laude). While working as a scientific assistant and researcher at the FUB he wrote his doctoral thesis and graduated in 1979 as a natural science doctor, Dr. rer. nat. (summa cum laude). His professional career as a scientific assistant and lecturer at the FUB came to an end in 1980. Ralf Janda also joined the dental industry in this year as head of research and development. He worked for many internationally leading dental companies (Kulzer GmbH, Germany, Degussa AG-Dental Division, today Degudent/Dentsply GmbH, Germany, Dentsply/Detech GmbH, Germany, Dentsply INC., USA, Dentaurum GmbH& Co. KG, Germany) in different leading positions as head of: R&D, production, quality assurance, dental technology, worldwide project leader until 2003. During this time, he was a member of many dental standard commissions, and from 1987 to 2000, he was also a member of the drug commission A at the drug institute of the Federal Republic of Germany. In 2003, he joined the cosmetic industry specialized on light-curing artificial nail products and stayed there until 2017. In addition to his professional pursuits, Ralf Janda has maintained a lengthy and extensive scientific career as a researcher and lecturer at numerous universities, beginning at the FUB in 1978. From 1988 to 1990, he was a lecturer at the Faculty of Material Sciences of the Technical University Berlin, where he taught resin composite materials. From 1991 to 1999, he worked as a researcher and lecturer for non-metallic dental materials at the dental department of the Medical Faculty of the Johann Wolfgang Goethe-University, Frankfurt/M. In 1992, he obtained his Habilitation (qualification for a teaching career at universities) and the degree Privatdozent (associate professor) in dental material science at the same university. From 1999 to 2004, Ralf Janda was Privatdozent at the Center of Dental Medicine of the Medical Faculty, Charité, Humboldt-University Berlin. From 2004 to 2021 he worked as a researcher and lecturer at the dental clinic of the Medical Faculty of the Heinrich Heine University, Düsseldorf. In 2006, he was appointed as apl. Professor (adjunct professor) in dental material science. Since 2021 he put his focus on writing textbooks about dental materials.

Terms and Definitions

1 Chemistry/Polymer Chemistry

Terms and definitions important in the context of this ebook or the dental literature are explained in accordance with the IUPAC definitions [80-83] or with the literature [29-32,85,86].

Additive: Any type of substance that is added in very small quantities to a monomer, oligomer or polymer to improve, alter, and stabilize or to change its properties in any requested direction.

Antioxidant: A substance that inhibits or reduces the oxidation of other molecules or macromolecules, respectively.Primary andsecondary antioxidants are differentiated.Primary antioxidants (mostly sterically hindered phenols or amine derivatives of higher molecular mass) are radical scavengers butsecondary are not.Secondary antioxidants (sterically hindered phenols of lower molecular mass, organic phosphites or organic sulfides) decompose hydroperoxides to form stable alcohols and, thereby, chain branching can be avoided. It is the common purpose of all antioxidants to hinder or to diminish polymer degradation due to oxidative processes and to preserve the polymer’s properties.

Catalyst: Atoms, molecules or ions which diminish the activation energy with the result that a specific chemical reaction can occur. The catalyst does not participate in the reaction but exists before and after the reaction in the same chemical condition.

Comonomer: A second monomer added to the main monomer.

Constitutional unit: A species of atoms or atomic groups in a macromolecule, polymer or oligomer.

Composite resin/composite plastic: A resin/plastic that contains organic and/or inorganic fillers in all kinds of shapes (fibers, splinters, platelets, crystals, spheres, ligaments, etc.).

Copolymer: A polymer derived from more than one species of monomer.

Copolymerization: Polymerization of more than one species of monomer in which a copolymer is formed.

Cross-linkers: Cross-linkers are multifunctional monomers which form covalent chemical bonds between two separately growing polymeric chains to form a firm polymeric network. For polymerization reaction at least bifunctional monomers are requested, for polyaddition and polycondensation the monomers must be trifunctional at least.

Degree of crystallinity: The percentage of crystalline amount in a thermoplastic polymer.

Degree of conversion: The percentage of monomers that polymerize and form the polymer.

Degree of cross-linking: Relates to the number of groups that interconnect two materials. It is generally expressed in mole percent (mol%).

Degree of polymerization: The number of monomeric units/repeat units in a macromolecule, an oligomer or chain. For homopolymers the number of monomeric units corresponds with the number of repeat units. For copolymers this is not always true and sometimes the degree of polymerization is defined as the number of repeat units. Considering polyamide 66 (PA 66), for instance, the repeat unit consists of two monomeric units (-NH-(CH2)6-NH-OC-(CH2)4-CO-) with the result that a chain of two thousand monomeric units have only one thousand repeat units.

Functional group: A group of atoms in a molecule which significantly determines the reactivity or properties of the molecule (e.g. double bonds, triple bonds, aromatic compounds and hydroxyl or carboxyl groups).

Homopolymer: A polymer derived from only one specific monomer.

Inhibitor = Stabilizer: A molecule which deactivates radicals to inhibit a premature or unintended free radical polymerization. Inhibitors/stabilizers act similar to primary antioxidants.

Initiator: One or more molecules or ions forming radicals under the influence of energy and, thereby, start the free radical polymerization. The initiator takes part in the reaction and is consumed. In case the energy involved is light the initiator is called photoinitiator or light-initiator, in case it is heat it is called thermal or heat initiator, and in case it is “chemical” energy it is called redox initiator.

Ligand: Atom, molecule, ion or radical chemically bonded to a central atom.

Macromolecule/polymer molecule: A molecule of high relative molecular mass, the structure of which derives essentially of the multiple repetitions of molecule units with relatively low molecular mass.

Macroradical: A macromolecule which is a radical.

Matrix resin: Unpolymerized monomer/oligomer blend or polymerized material that may contain different types of fillers (organic or inorganic), initiators, catalysts, stabilizers, pigments or various types of other additives.

Molecule: Two or more identical or different atoms chemically bonded to each other.

Monomer molecule, functionality: It is differentiated between mono-, bi-, tri-, tetra- or penta-functional monomer molecules. Monofunctional molecules have one reactive group, bifunctional have two, trifunctional have three and so on reactive groups to run a polyreaction. Monomers with more than one functional group are also called multifunctional or higher functional monomers; they function as cross-linkers.

Monomer molecule: A molecule which can polymerize and contributes a constitutional unit to the structure of a macromolecule. In other words: the smallest molecule which repeats oneself during a polymerization to form a polymer/macromolecule.

Monomer: A substance composed of molecules each of which can provide one or more constitutional units to a polymer.

Monomeric unit/monomer unit: The largest constitutional unit contributed by a single monomer molecule in a polymerization process to the structure of a macromolecule or oligomer molecule.

Oligomer molecule: A substance of intermediate relative molecular mass composed of a few or more constitutional units repetitively linked to each other. The properties of an oligomer vary with the additio