Dental Materials Final Study Guide | Answered with complete solutions

Dental Materials Final Study Guide | Answered with complete solutions List the three types of impressions that would be taken in a dental office. preliminary final occlusal Describe the types of impression trays and their characteristics of use. quadrant trays- impressions of specific quadrant of mouth section trays- impressions of specific sections of the mouth full arch- impression of the maxillary or mandibular arches of the mouth Discuss hydrocolloid impression materials, and describe their use, and application of material. hydrocolloid meaning water a gelatinous substance solid changed by chemical changes/ factor Discuss elastomeric impression materials, and describe their use, mixing techniques, and application of material. polysulfide- long working setting time polyether- better mechanical polysiloxane- high stability, low odor, low tear resistance silicane- condensation easy mix Describe the importance of an occlusal registration and its use. accurate impression of the prepared teeth A(n) ________ is a gelatinous material used to obtain impressions. Colloid __________ is the process of using your fingers to achieve a closer adaptation of the edges of an impression. border molding A(n) ________ material has elastic properties and is made from rubber. Elastomeric A foundation or basic ingredient of a material is the ________. Base To have something _____ is to have it centered, such as your maxillary teeth centered over your mandibular teeth. Centric ________ is a gelatin-type material derived from seaweed. Agar ________ is the loss of water, causing shrinkage. Synthesis __________ is to bring a material to a desired temperature and consistency. Tempering __________ describe a property of fluids with a high resistance to flow. Viscous __________ is the material of choice in dentistry for preliminary impressions. Alginate __________is to transform a material from one one physical state to another. Hystorsis ______ means water. Hydro A(n) __________ is a reproduction of someone's bite with the use of wax or elastomeric material. occlusal registration A(n) _________ is a substance that modifies or increases the rate of a chemical reaction. Catalyst _________ is the absorption of water, causing an object to swell. Imbibition An impression would be considered a ________. negative reproduction Of the three classifications of impressions, which of these would be considered an expanded function for the certified dental assistant? irreversible hydrocolloid Which of the three classifications of impressions would be used by the dental lab tech for the occlusal relationship? bite registration Which type of stock tray would you select to cover half of an arch? Quadrant Which type of tray allows impression material to mechanically lock on? Perforated Which typ e of tray is constructed to fit the mouth of a specific patient? custom __________ is used to extend the length of a tray to accommodate third molars. rope wax The organic substance of hydrocolloid material is _________. Seaweed Why would a fast-set alginate be selected for taking a preliminary impression? the patient has a strong gag reflex Give the powder/water ratio for a maxillary impression. 3 scoops of powder to 3 measures or water Hydro means ________. Water Another name for irreversible hydrocolloid is ___________. Alginate How is irreversible hydrocolloid mixed? mixing bowl Where is the reversible hydrocolloid material placed before the impression is taken? patient tray Elastomeric materials would be selected for what type(s) of impression? Final How are elastomeric materials supplied? paste cartridge putty Which viscosity of a final impression material is applied first to the prepared tooth or teeth? light body Another name for polysulfide is _______. rubber base What would the dentist use to express the light-body impression material around a prepared tooth? extruder with tip Discuss the types of safety precautions that should be taken when working in the dental laboratory. spatula and pad List the types of equipment commonly found in a dental laboratory, and describe their use. baseplate wax Define dental models, and explain their use in dentistry. gauze tray Discuss gypsum products and their use in fabricating dental models. Warmed Describe the three types of custom impression trays and their use in dentistry. readying the tray with heavy-body material Describe the types of dental waxes and their use in dentistry. rinsed, disinfected, wrapped in a moist paper towel, and placed in a precautionary bag A material that is uniform in quality and consistent throughout is said to be __________. Homogenous A(n) _______ is a machine used for cutting or polishing dental appliances. Lathe ________ is the mineral used in the formation of plaster of Paris and stone. Gypsum A substance is said to be _________ if it has an explosive property. Volatile When referring to a gypsum product, a(n) _______ indicates that there are two parts of water to every part of calcium sulfate. Dihydrate If an object is resistant to change in width, height, and length, it is said to be ________. dimensionally stable The _____ is the portion of an articulator used to measure the upper teeth and compare with the temporomandibular joint. facebow A(n) ______ is the compound of many molecules. Polymer _______ is a chemical process in which crystals form into a structure. Crystallization _______ is the removal of one-half part water to one part calcium sulfate to form the powder product of gypsum. Hemihydrate A(n) ______ is a replica of the maxillary and mandibular arches made from an impression. Model ___________ refers to the structural portion of a dental model. anatomic portion A(n) ________ is a dental laboratory device that simulates the movement of the mandible and the temporomandibular joint when models of the dental arches are attached. Articulator A(n) ________ is a molecule that when combined with others forms a polymer. Monomer _________ is a mixture of gypsum and water used in the finishing of models. Slurry Where would you commonly find the dental lab in a dental office? in a separate place away from patient care Which specialty practice(s) might have a more extensive laboratory setup? fixed prosthodontics orthodontics An example of a contaminated item that could be found in the dental lab would be a(n) ________. Impression Which piece of lab equipment would be used to grind away plaster or stone? model trimmer Which piece of lab equipment would be dentist use to determine centric relation from a diagnostic model? articulator The size of the wax spatula most commonly used in the laboratory is a ______. #7 Another name for a dental model is _______. dental cast What dental material would be selected to fabricate dental model? Gypsum Which form of gypsum is used to fabricate a die for making an indirect restoration? high-strength stone The powder/water ratio of plaster for pouring a dental model is ________. 50/100 When a gypsum material is mixed, how is the powder and water incorporated? add powder to the water How are gypsum materials mixed? using a spatula and rubber bowl Which of the following is a section of a dental model? anatomic art When pouring an impression, where would you begin placing the gypsum material in a mandibular impression? most posterior tooth How long should you wait before you separate a model from its impression? 40 to 60 minutes Which of the two models (maxillary or mandibular) do you begin trimming first? Maxillary What is the one specific area of a dental model in which the maxillary and mandibular models aren’t trimmed differently? anterior portion What should be placed between the two models when they are trimmed together? wax bite Of the three types of custom trays discussed in the chapter, which technique uses a volatile hazardous material? acrylic resin What type of custom tray would be made for a vital bleaching procedure? thermoplastic resin How is self-cured acrylic resin supplied for the fabrication of custom trays? powder and liquid What type of wax is used to form a wall around a preliminary impression when it is poured up? boxing wax To extend an impression tray, what type of wax is used? rope utility wax What type of wax is used to get a patient's bite? baseplate wax Articulate to match the maxillary to the mandibular occlusion together Articulator a mechanical hinge and frame that holds models of the patients teeth to maintain the occlusion representing his or her jaws Calcination the process of removing water from hard stone to create gypsum material Die stone used in in the dental laboratory for fabrication of crown and bridges Gypsum rock- derived product delivered in a fine powder; used for a variety of dental procedures, including replicating oral structures Study model a replica of the patients oral structures poured in gypsum for use in prosthetics or orthodontics Plaster of paris one of the oldest gypsum products used in dentistry Model trimmer dental equipment piece used to trim prosthetics Lathe polish or fine trimming Vibrator used to evenly mix stone and plaster materials Why should a dental assistant place and rotate the bowl on the vibrator platform? allows the bubbles to rise to the surface Why should the dental assistant avoid covering any margins of the periphery of the impression tray with plaster? because it will be trimmed off and when removing the plaster from the impression the plaster may crack or break Why should the dental assistant soak the models in water-filled rubber mixing bowls for 5 minutes, prior to trimming them? helps the grinding wheel on the model trimmer work more efficiently and with less friction Which dental procedures are study models used in? prosthodontics and orthodontics What is the correct water to powder ratio for type 1 impression plaster? 60 ml water to 100 grams powder What is the correct water to powder ratio for type 2 laboratory or model plaster? 50 ml of water to 100 grams powder What is the correct water to powder ratio for type 3 laboratory stone? 30 ml of water to 100 grams of powder What is the correct water to powder ratio for type 4 die stone? 24 ml of water to 100 grams of powder What is the correct water to powder ratio for type 5 high strength stone? 18-22 ml of water to 100 grams of powder The setting time for type 1 impression plaster is __________ minutes. 4-5 minutes Impression registration (bite wax) used to record a patients centric occlusion Pattern wax sometimes referred to as inlay wax used on a die which is a positive replica of a prepared tooth poured in stone Processing wax those most commonly used in dentistry includes boxing wax, utility wax, and sticky wax Study wax hard wax manufactured in blocks used primarily for educational purposes to teach carving of teeth and dental anatomy Undercut wax used to fill undercuts of dental structures prior to taking impressions Why must the dental assistant take great care to store dental waxes away from excessive heat? because of dental waxes low melting point When taking a wax bite, why must the wax bite registration material be heated in a bowl of water first? to make wax pliable When taking a wax bite registration, why might the dental assistant be asked to apply compressed air to the wax while the patient holds it in centric position? facilitate cooling of the wax ______ wax is hard and brittle. It is heated to form the initial base in processing dentures. Sticky ______ wax is used to bead around the periphery or impression trays to extend them to ease patient comfort. Utility Gel semisolid state of a hydrocolloid Hydrocolloid impression material used for taking preliminary impressions of the oral structures; may be either irreversible or reversible Polyether impression material used in prosthodontics Polysiloxane/polyvinyl a dental impression material used when sharp detail is required; most often used in crown and bridge cases and for the fabrication of dental implant prosthesis Retarder a material used t make final impressions comprised of a base and lead peroxide accelerator Sol a liquid Imbibition enlargement due to the absorption of fluid Syneresis shrinkage due to loss of water content from heat, dryness, or exposure to air Bite registration an occlusal record of the relationship between the upper and lower teeth Why are three scopes of alginate powder and three increments of water required for each maxillary full-arch impression instead of two each as for the mandibular arch? because the maxillary arch impression includes the surface area of the hard palate When both maxillary and mandibular impressions are required, the mandibular impression is taken first. Why? is to introduce the patient to the impression procedure as well as because patients are more likely to experience a gag reflex when the maxillary impression is taken What are some of the disadvantages of using polysulfide rubber-base impression material? must be poured within 30 minutes shrinkage difficult to spatulate relatively long time to set sulfur like odor (rotten eggs) color lacks esthetics What are some of the advantages of polyvinylsiloxanes? must be poured within 30 minutes poor tear strength shorter shelf life must not contact latex gloves may produce hydrogen gas on setting that could affect pouring the cast shorter spatulation and working time What is the purpose of taking a bite registration? to record the patients normal occlusion when closing the maxillary and mandibular jaws When mixing alginate, as the water temperature increases, the working time. Decrease Mixing time for type 1 alginate takes _______ seconds. 60- 120 Alginate impressions are used routinely in dentistry to make upper and lower study models for: fixed and removable prosthetics, orthodontics, appliances, mouth guards, bleaching trays, provisional restorations, and custom acrylic trays When removing any type of impression tray from the oral cavity, the operator should place his or her fingers of the opposing hand on the patient's opposite arch to: insure the arch is evenly set and that the motion of pulling out will not break the arch Which disinfectants are recommended by the ADA for alginate impression? spraying and wrapping in diluted hydrochlorite, iodophor, or glystradhyde with phenioc buffer ______ is any push or pull on an object, the result is resistance Force The ability of a material to withstand forces of tensile stress without failing or becoming altered __________. Ductility ______ the change produced within the material that occurs as the result of stress. Strain ______ pulls and stretches the material tensile stress A patient reports clenching his teeth when he is concentrating hard at work (which stress is this)? shearing stress _____ occurs when the dental material is subjected to heat; and the dental material shrinks, then expands when the heat source is removed. Expansion Why is knowledge of dental properties important to the dental assistant? to where she or he can perform well alone if qualifications say okay and can assist the dentist to the very brief possible What does the term universal (standard) precautions mean, and why is it important to all members of the clinical dental team? treating everyone who enters your office as if they have a communicable disease What is the single most important component of PPE? Gloves Why is it important for the dental assistant or office manager to be familiar with dental material supply ordering and inventory management? so that they save money and have all supplies needed to do operations Armamentarium being able to set up equipment and supplies PPE personal protective equipment Universal standard precaution treat all patients as if infected with a communicable disease Shelf life amount of time dental material is usable prior to the expiration date marked on the packaging label Toxicity degree to which a material is harmful Dimensional change change of length of volume of dental material Ductility ability of material to withstand tensile stress without fabrication Malleability metal being compressed permanently without rupturing Viscosity ability of a liquid to flow Wettability ability of a liquid to flow over a hard or solid surface Initiator a substance that contains molecules that cause or initiate a polymerization reaction Activator a chemical, usually an a mine compound that causes initiator molecules to become active and to begin a polymerization reaction Bonding agents a low viscosity resin used to improve retention between two objects Acid etch technique a phospheric acid is applied to s tooth which allows for adhesion of dental materials What is the primary use of calcium hydroxide cavity liner? a cavity liner, cement base Calcium hydroxide liner is supplied in the following forms: powder/ liquid two paste system Cavity varnish is ________ in the oral cavity. Insoluble Cavity varnish is usually applied in two coats, within ________ seconds to ensure a uniform coating and sealing of the dentinal tubules. 20-30 The dental assistant should regularly add______ quantities of solvent to cavity varnish to keep it diluted. Medium How is etching gel supplied? bottles or syringes When properly etched, the natural tooth will have a/an _____ appearance. Rough Bonding agents are an effective method of sealing resin restorations. True Exothermic reaction a chemical reaction which heat is released Luting to cement the process of attaching one structure to another Liner a material placed in a thin layer on the walls and floor of a cavity preparation Seadative/ palliative effect a soothing effect Base material applied in a putty or thick layer between the tooth Why is it important to use a cool, dry glass slab when mixing zinc phosphate cement? heat can cause more or less water which may cause the material not to sit properly dry is because extra water may dilute the material How is zinc phosphate supplied? powder/liquid When zinc phosphate cement is mixed it gives off what type of reaction?