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Materials/supplies
Vet Dentistry
| Question | Answer |
|---|---|
| what is the most commonly used chelating agent in root canal treatment? | EDTA: ethylenediaminetetraacetic acid |
| What is the purpose of a chelator | softens inorganic structures: softens internal dentinal surface so files can remove innermost layers that harbor bacteria Also acts as lubricant |
| What is the advantage of the urea peroxidase in RC Prep? | aids in dissolution of organic debris, provides some antibacterial activity |
| What is the most commonly used endo irrigant? | 5.25% sodium hypochlorite NaClO3 |
| Why is a sealer cement recommended in combo with the core filling material in root canal tx | To enhance the apical hermetic seal |
| what are the 2 components of ZOE | zinc oxide powder + eugenol |
| how does one evaluate the consistency of ZOE | draw up a thread of paste from the mixing slab, should be able to get 1-2 cm from slab |
| What are drawbacks of ZOE? | extrusion may cause mild irritation to periapical tissues ZOE can be resorbed over time (not a big pbm for dogs due to shorter lifespan) Composites cannot be used directly over eugenol b/c interferes w/setting time |
| Why are noneugenol sealer cements advocated by some dentists? | ZOE may eventually disintegrate, can be cytotoxic, and can be antigenic to living tissues |
| How are therapeutic sealer cements classified and what do they contain? | Biologically active (incorportate calcium hydroxide) |
| What are the requirements for an ideal root canal filling material? | non-irritating impervious to moisture radiopaque conformability to internal canal Easily removed Does not stain does not encourage bacterial growth |
| What is the shape/size difference of Type I vs. Type II Gutta percha points? | Type I: standard, sizes approximate files Type II: accessory/auxilliary. More tapered |
| What are 2 liquids that can be used to soften Gutta percha | Chloroform (carcinogenic) Oil of Eucalyptus |
| What are the ideal properties of a restorative material? | should chemically bind to dentin & enamel should not break, fatigue, or distort after placement should have the same coefficient of expansion as teeth should have high impact strength should wear at the same rate as teeth |
| What are disadvantages of acrylics as restoratives? | high shrinkage during polymerization lack of resistance to wear |
| What are acrylics useful for in dentistry? | Intraoral splints, orthodontic appliances, temporary crowns, denture bases, custom trays |
| What is the common organic polymer matrix component of composite restorative materials? | Bisphenol A-glycidyl methacrylate resin (Bis-GMA) which has a high molecular weight |
| What are unfilled resins used for? | to coat or line the area to be filled and to help decrease microleakage |
| What is the purpose of acid etching enamel? | Creates microporosities that unfilled resin or bonding agent can flow into to enhance bonding strength and increase retention and resistance to microleakage at the margin |
| What is the purpose of added fillers in composites? | Increase hardness, strength, resistance to temperature, ability to withstand wear, and control of shrinkage during polymerization |
| What other qualities to fillers contribute to composite materials? | Lower water absorption greater wear resistance alter polishability alter color |
| What determines most of the composite's characteristics? | Size of filler particles |
| What are the advantages of a microfill composite? | high polishability so it is esthetically advantageous in non-stressed areas |
| What are the categories of composites according to filler content? | microfill-->intermediate fill-->conventional fill. Also, hybrid products |
| What happens to strength and polymerization shrinkage of material as filler particle size increases? | bigger particles=increased strength and decreased shrinkage |
| What happens to polishability as filler particle size increases? | bigger particles=decreased polishability |
| What is the greatest advantage of light cure composites over self cure acrylics? | operator control of polymerization |
| Where on the teeth are glass ionomers most useful? | Non-occlusal areas (class V, Modified Black Classification) |
| How do glass ionomers bind to dentin and enamel? | chemically: ions form salts that bond to the calcium in the tooth |
| What are characteristics of type I Glass ionomer? what are they used for? | finely grained, used for luting and cementation of of crowns/bridges |
| What are characteristics of type II Glass ionomer? what are they used for? | coarser than type I, esthetic restorations |
| What are characteristics of type III Glass ionomer? what are they used for? | base and liner materials: it can be acid etched and a composite an then be bonded to it for a sandwich effect (i.e. to separate composite from ZOE) Used as restorative in tx of feline dental dz |
| What are characteristics of type IV Glass ionomer? what are they used for? | contain metal admixtures: silver, amalgam, gold, titanium sometimes used for cores/build-ups but they're weaker than composites |
| How is amalgam advantageous compared to glass ionomers? | Amalgam has better strength and resistance to wear and fracture |
| What is the composition of amalgam? | Finely powdered metals mixed with mercury which is a liquid at room temps |
| What are typical components of amalgam? | silver, tin, copper, zinc |
| What type of metal should constitute <0.01% of amalgam used to restore apicoectomy sites? why? | zinc. it reacts with moisture in periapical tissues and forms bubbles of hydrogen gas |
| What is the problem with undermixing amalgam | results in a grainy, dull marterial with a roughened, weakened surface and potentially more exposed to mercury |
| What is the problem with over mixing amalgam | causes the alloy to set up too quickly |
| How is amalgam retained as a restoration? | relies on undercuts for mechanical retention. It doesn't chemically bond to dentin or enamel and it doesn't flow into mircroporosities after acid etching |
| What eliminates microleakage at the margins of an amalgam restoration? | corrosional products i.e. tin and silver sulfides |
| With what restoration material are cavity varnishes CONTRA-indicated? | composites |
| With what restoration material are cavity varnishes indicated? why? | amalgams: protect irritation of the pulp, provide a marginal seal to reduce microleakage, reduce seepage of corrosive amalgam that causes discoloration |
| What type of material is used to apply orthodontic brackets, appliances, crowns, or other prosthodontic devices? | cements Type I (fine particle size) zinc phosphate for precision appliances/crowns Type II (medium particle size) orthodontic bands |
| How do calcium hydroxide liners induce repairative dentin bridge formation? What is the purpose of this? | irritate odontoblasts. protects the pulp |
| When is it indicated to use CaOH liner? | When there is </= 0.5 mm dentin covering the pulp |
| What are advantages of using Glass Ionomer liner over CaOH? What type should be used? | Greater tensile & compressive strength bonds to dentin releases flouride: cariostatic can be acid etched to bond to composite Type II or type I (which has lower viscosity) |
| What are two types of cements? | Zinc phosphate polycarboxylate |
| What is a disadvantage of Zinc phosphate cement in vital teeth? | Phosphoric acid component can penetrate through dentinal tubules to irritate or kill the pulp |
| What are disadvantages of polycarboxylate cements? advantages? | weak bonding to gold and porcelains good adhesive bond to enamel, dentin, stainless steel Less acidic, possb. less irritating to vital pulp tissue short working time thick consistency |
| What determines the success of function and fit of orthodontic and prosthodontic appliances? | Accuracy of the model in replicating the oral tissues, which depends on the accuracy of the impressionn/placement plasticity when placed flowability to enter/record fine details reasonable working/setting times |
| What are desirable qualities of impression material? | nontoxic nonirritating clean to use acceptable taste/odor good shelf life economical ease of maniupation elasticity to allow easy removal of the model retention of dimensional stability |
| What are the 4 main groups of NONELASTIC Impression materials? | Impression plaster Impression compound (THERMAPLASTIC) Impression ZOE Impression waxes |
| What are non-elastic impression materials generally used for? | Edentulous areas Impression waxes used for bite registration |
| What are 2 categories of elastic impression materials? | Hydrocolloids synthetic elastomers |
| What are 2 types of hydrocolloids? | Alginate (irreversible hydrocolloid) Agar (reversible hydrocolloid) |
| What are 3 types of synthetic elastomers? | Polysulfides polyethers silicones (silicone rubber, polysiloxane) |
| What are the two types of alginates? what are their setting times? | Type I: fast setting (1-2 minutes) Type II: regular-setting (2-4.5 minutes) |
| What does using cool water do to the set time of alginate | prolongs it |
| What are advantages of synthetic elastomer compared to hydrocolloids? Disadvantages? | Better tear resistance and dimensional stability BUT more $$$ |
| What are advantages of polysulfide rubber impression materials? | good accuracy and tear resistance |
| What are disadvantages of polysulfide rubber impression materials? | long setting time (10 min) and contain lead odorous and can cause dental staining |
| How is viscosity described in synthetic elastomers? | Light body Medium or regular body Heavy body |
| When using vinyl polysiloxane, should one wear gloves? | no because the powder or vinyl can interfere with setting of the material |
| What is the main disadvantage of vinyl polysiloxane? | cost |
| What is Gypsum? Give an example | chalky, porous white mineral: calcium sulfate dihydrate Plaster of Paris |
| What is the dental powder product that is used to make models? | calcium sulfate hemihydrate (when mixed with water,reacts to form CaSO4 dihydrate and heat) |
| What is the main difference between plaster and stone? | The shape of the calcium sulfate crystals |
| What is the shape of crystals in plaster? how does it affect properties of the material? | irregular crystals are weak and require more water to return to the dihydrate form |
| What is the shape of crystals in stone? How does it affect properties of the material? | WELL FORMED, DENSE CRYSTALS REQUIRE LES WATER TO FORM DIHYDRATE CRYSTALS RESULTING IN DENSER AND HEAVIER MATERIAL WITH GREATER COMPRESSIVE STRENGTH AND RESISTANCE TO ABRASION |
| How does increasing speed or time of spatulation change setting time? | Increased spatulation decreases setting time by fracturing crystals to form more nuclei for increased spread of the setting rxn |
| How can one decrease air bubble formation during spatulation of stone? | by adding powder to water (premeasured) |
| What are inlay waxes used for? | fabricating wax patterns for crowns, bridges, and some other dental appliances |
| What are 2 kinds of inlay waxes? | Type I: direct Type II: indirect |
| What are necessary characteristics of Direct inlay waxes? | Low flowability b/c of warm temp in mouth (result is a harder wax) |
| What are advantages of Indirect inlay wax? | Can have higher flowability b/c working at lower temps, softer wax easier to carve |
| What technique is used to fabricate the actual restoration/appliance once the wax pattern is created? | "Lost wax technique" |
| What are casting waxes used for? | to produce patterns for metallic framework of removable partial dentures, orthodontic frames |
| How are casting waxes different than inlay wax? | More tacky (maint. position on model) greater ductility for pliability (bend w/o breaking) |
| What is sticky wax used for? | to temporarily stick or fix various dental appliances to stone or plaster dental models |
| What is BOXING WAX used for? | to hold freshly mixed plaster or stone solution in and on the impression when poured. |
| What is another name for BOXING WAX? | carding wax |
| What is UTILITY WAX used for? | increasing height of impression tray cover rough edges on orthodontic appliances to protect mucous membranes |
| How is BITE REGISTRATION WAX used? | A rolled sheet is placed behind the 1st premolars and the bite is closed to imprint the articulation |
| What are 2 topical protective periodontal medicaments? | Orabase Tincture of Myrrh & Benzoin |
| What do protective periodontal medicaments do? | provide a protective barrier, sooth discomfort, carry or seal other drugs in the gingival sulcus |
| What are periodontal packs used for? | Adhesive putty applied over perio sx sites to reduce pain, hemorrhage, trauma, and debris packing due to mastication while acting as a barrier to bacteria and support for mobile teeth-->promote healing |
| What is the most common non-epinephrine hemostatic solution? | Aluminum chloride |
| How does aluminum chloride work? | Acts as an astringent to produce contraction of the tissues and reduce sulcal secretions and minor hemorrhage |
| What benefits are provided by fluoride? | has asdverse effects on some of the types of bacteria that are found in caries and periodontal lesions can inhibit plaque formation can reduce dental sensitivity |
| What are problems associated with excess fluoride? | Adverse effects on Calcium metabolism Adverse effects on the GI system nephrotoxic possibly genotoxic |
| What are advantages of chlorhexidine solutions? digluconate, gluconate, and possibly acetate) | inhibit development of plaque/calculus inhibit onset of gingivitis |
| What are DIS advantages of chlorhexidine solutions? | bitter taste can cause skin & mucosal irritation if prolonged contact time or high concentration can stain oral tissues and appliances brown irritating to eyes ototoxic--->deafness if contacts middle ear |
| What are benefits of ZINC ASCORBATE solutions? What veterinary product uses this solution? | Support collagen synthesis (stimulate healing post-op) and reduce oral mal-odor Maxiguard Oral Cleansing Gel |
| Stabilized chlorine dioxide is used in which product? | Oxyfresh, reduces oral malodor |
| What are lactoperoxidase and glucose oxidase? What do they do? | enzymes that augment normal salivary peroxidase production mild antiplaque and antibacterial effect |
| How are lactoperoxidase and glucose oxidase used? | added to dentrifice to improve performance with less mechanical action |
| What happens to the germicidal effect of hydrogen peroxide when it contacts tissues? | it is diminished b/c hydrogen peroxide rapidly deteriorates in the presence of organic matter |
| What is a die? JVD Summer 2013 | An especially accurate replica of a single tooth used in the manufacture of crowns |
| What is a study model? JVD Summer 2013 | positive reproduction--replica--used to evaluate disease and plan tx (orthodontics) |
| What is a cast? JVD summer 2013 | positive reproduction--replica of oral tissues used to manufacture orthodontic appliances or fabricate crowns |
| What is the property of thixotropy? JVD Summer 2013 | viscous under normal conditions but become less viscous, allowing better flow when stressed or agitated |
| How long does it take Type I alginates to set? Type II? | Type I = fast set (1--2 min) Type II = regular set (2-4 min) |
| impression materials make a ______ reproduction of a structure JVD Summer 2013 | negative |
| gypsum or epoxy are used to make a replica, or _____ reproduction of a structure from impressions JVD Summer 2013 | positive |
| Name 3 inelastic impression materials JVD Summer 2013 | Impression compound, impression plaster, zinc oxide-eugenol |
| Name 6 elastic impression materials JVD Summer 2013 | Agar hydrocolloid, alginate hydrocolloid, polysulfide, condensation silicone, polyether, addition silicone (PVS) |
| What are 5 important qualities of impression materials? JVD Summer 2013 | Accuracy, elastic recovery, dimensional stability, flow/flexibility, hydrophilicity/wettability |
| To what level of detail are low viscosity (light body) impression materials required to record? High viscosity (putty)? i.e. accuracy | 25 um vs 75 um |
| What kind of impression materials can successfully record an undercut? JVD Summer 2013 | elastic |
| Which impression materials possess ideal dimensional stability? why? JVD Summer 2013 | PVS. they have no by-product in the chemical setting reaction |
| What properties of alginate give it poor dimensional stability? JVD Summer 2013 | syneresis (H20 evap'n) & imbibition (H20 absorp'n) |
| Within what time frame should an alginate impression be poured up? JVD Summer 2013 | < 1 hour |
| What is THIXOTROPY (property of impression material)? JVD Summer 2013 | viscous under normal conditions and becomes less viscous allowing better flow when stressed/agitated |
| Which is the most flexible impression material? JVD Summer 2013 | alginate |
| What are the two classes of hydrocolloid impression materials? JVD Summer 2013 | reversible (agar) vs. irreversible (alginate) |
| How long should a regular set alginate be spatulated? JVD Summer 2013 | 45 sec |
| What is the difference in hydrophilicity/wettability of alginates compared to VPS? JVD Summer 2013 | alginates are more wettable, better to use on moist teeth (or will bond to enamel and increase risk of tearing). VPS are not wettable, work better on dry teeth |
| monocryl and vicryl are available now with a coat of ___ to create a zone of inhibition around the suture line JVD fall 2014 | triclosan |
| What is triclosan? JVD fall 2014 | broad-spectrum antibmicrobial agent (even effective against methicillin resistant bacteria) |
| What material is used to make 'gut' suture? JVD fall 2014 | cow intestinal serosa, sheep intestinal submucosa |
| How is gut suture treated to make it longer lasting? JVD fall 2014 | coated with chromium salts & glycerol |
| How is gut suture absorbed? JVD fall 2014 | 2 stages: collagenolysis, then proteolytic enzyme digestion |
| What is the longest lasting synthetic absorbable suture? JVD fall 2014 | Polydioxanone (PDS) 182 days |
| How does zinc polycarboxylate chemically bond to dental tissue? | carboxyl group appears to bond to Ca2+ ion at the surface of the tooth enamel or dentine |
| What is the advantage of zinc polycraboxylate cement over zinc phosphate cement? | zinc polycarboxylate cement chemically bonds to the tooth surface |
Created by:
lamarron
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