Learning objectives
To give to the student the basic concepts for a skill biomaterials employ in dentistry. Especially important for the student to well understand physical and chemical laws undergoing to the biomaterials. The student has also to well know clinical employ of biomaterials in every dental treatment
Course unit content
MAIN GENERAL PHISICS AND MECHANICAL CONCEPTS
Hooke’s law, single and couple of forces. Physics characters of bodies. Metallic alloys and their chemical physical characters.
IMPRESSION MATERIALS Physical, chemical and clinical characters of the main impression materials as alginate, hydrocolloid, silicone etc.
CEMENTS AND GLASS-HYONOMERICS MATERIALS Physical, chemical and clinical characters of the cements as silicate, Zn oxide, eba, etc. and glass hyonomers
POLYMERIS Physical, chemical and clinical characters of the polymers as polisulphures, silicones, poliethers, polivinilsiloxanes, etc.
MATERIALS IN ORTHODONTICS
A short history of orthodontic materials. Brackets and bands. Different techniques: friction and frictionless appliances, continuous and segmented techniques. S.S., Co-Cr, Ni-Ti ecc. Alloys. Stiffness, strenght and range. Loops theory.
COMPOSITES AND RESINS
Physical, chemical and clinical characters of the composites and resins as bisfenologlicidilmetacrilate, hybrid composites, photo-activation, polimetilmetacrilate etc.
ADHESION
Different physics and chemical mechanisms of adhesion
CERAMICS
Physical, chemical and clinical characters of ceramics in dentistry.
Full programme
GENERAL CONCEPTS OF PHYSICS AND METALLURGY
Elasticity and Hooke's law. Individual forces and moments developed by steel wires in the three planes of space. Biofunctionality and biocompatibility. Solid body; stutture crystal; elementary cells, lattices. point defects, linear, extended. dendrites, precipitates, eutectic. -Metals and alloys. cohesive gold. phase diagrams. system-au cu. noble alloys. alloys for removable dentures, for metal-ceramics. steels. titanium. alloys Ni-Ti shape memory. system ag-sn. amalgams, phase 2, the components minority dimensional variation, mechanical and chemical properties, toxicity. properties of alloys. elastic deformation; resilience. hardness. chemical and electrochemical corrosion in the oral cavity.
IMPRESSION MATERIALS
elastic and non-elastic. composition and properties of plaster, wax, zinc oxide and eugenol paste. variation of hardness with the method of polymeric materials from shore to imprint during the reaction. reproducibility of the detail of impression materials. Reversible and irreversible hydrocolloids. sodium alginate; composition, setting reaction and properties. agar and its properties, properties of impression materials: dimensional variation, reproducibility of detail, hardness, wettability, adhesion, tear strength, viscosity, viscoelasticity, elastic recovery, permanent deformation, thixotropy. model voigt-maxwell
CEMENT.
cements phosphoric acid calcium hydroxide cements, silicate cements, cements the EBA. triossidi cements. -
Glass ionomers.
gic glass ionomers. salification reaction. the resin-modified glass ionomers rmgic; mechanisms of polymerization and hardening the glass ionomer triple-reaction. the glassy materials filling. reinforcing cariostatici. state diagram of ternary systems. microstructure and nanostructure. proton attack and fluoride release. dimensional variation, hardness, porosity, swelling in the mouth.
POLYMERS IN DENTISTRY
structure and general properties. properties of macromolecules. length, weight, and average size of a macromolecule. the macromolecule in solution and in the condensed state. amorphous and crystalline polymers. models of creep and viscoelasticity in the amorphous phase. mobility of macromolecules. stages of the polymerization. -Polycondensation. polysulfides, silicones by condensation composition and reaction. -Polyaddition. mechanisms of polyaddition. polivinilsilossani; polyethers; composition and reaction.
THE MATERIALS IN ORTHODONTICS
An outline of the historical evolution of the product category in orthodontics. The brackets and bands. Various techniques: the clutch and non-clutch, continuous and segmented arches. The pre-information. Steels, NiTi alloys, Co-Cr alloys, alloys thermal transition phase. Concepts of stiffness, strength and range. Theory of the loops.
Thermoplastic and thermosetting resins.
polymethylmethacrylate. resins for dental implants. resins based on polymethylmethacrylate termopolimerizzabili, self-curing, polymerizable microwave. hardening reaction properties. transitions of the first and second order. resins for rebasing of dentures. -Composite resins. nomenclature. composition.
COMPOSITE
based bisfenologlicidilmetacrilato. the reinforcing. Micro-filled composites. hybrid composites. curing mechanisms, self-activation; photoactivation. the system activator-initiator. polymerization by irradiation. the system camphorquinone-tertiary amine. degree of conversion polymer. color. hue, brightness, saturation. Munsell system .. primary and secondary colors. Additive and subtractive combination. system c.i.e ici chromaticity diagram •. practical exercises:
LIGHT BLUE.
lamps by radiation, optical and thermal properties. halogen light, plasma, l.e.d., laser. light intensity and mode of radiation used in dental practice. sequential irradiation. temperature-induced irradiation. dimensional variation of composite resins during polymerization with blue light. mechanical properties, dimensional change, absorption of oral fluids, fracture toughness and corrosion, porosity.
ACCESSION.
micromechanical adhesion, chemical bonding .. adhesion to enamel, dentin bonding. the etching; auxiliaries accession (primers) the dentin adhesives. classification of the cavity and c factor. polymerization shrinkage, seal marginal microleakage; hybrid layer; nanoinfiltrazione.
DENTAL CERAMICS.
porcelain low, medium, and high temperature cooking. composition. structure. • responsiveness of the phase vetrosa. hydroxyapatite. synthesis, structure, properties.
TOOTHPASTE.
composition; function of the constituents.
Bibliography
G. SPOTO e A.A. VARI.: M. MATERIOALI E TECNOLOGIE ODONTOSTOMATOLOGICHE. ED. ARIESDUE 2002
SIMIONATO. SCIENZA DEI MATERIALI DENTARI, ED. PICCIN 1995, VOL. 1 E 2
CRAIG. MATERIALI PER L’ODONTOIATRIA RESTAURATIVA, ED. MASSON, 1997.
NEGRI, DELLA VENTURA, ERAMO. MATERIALI DENTARI, ED. USES, 1992.
