Term
Which of the following will decrease polymerization shrinkage:
1. Using composite with less filler particles to resin matrix ratio
2. Using a self-cure composite
3. Bulk fill with light-cure composite |
|
Definition
2. Using a self-cure composite
HIGHER filler particle ratio causes less polymerization shrinkage, while Bulk filling will increase polymerization shrinkage |
|
|
Term
| What is the difference between and inlay and an onlay? |
|
Definition
| Inlays are used when no cusp tips are involved. Onlays are for when you have missing cusps, but you still have at least one cusp left. |
|
|
Term
The following are all reasons to avoid using an onlay, EXCEPT one:
1. Para-functional habits
2. short teeth
3. You have a conservative preparation
4. pin placement is indicated |
|
Definition
4. pin placement is indicated
Short teeth do not allow for the room necessary to seat and adhere onlays. |
|
|
Term
Which of the following reasons is not a "selling point" about onlays:
1. Better contours and occlusal anatomy.
2. Higher mechanical properties
3. tooth structure preservation
4. Better esthetics |
|
Definition
3. Tooth structure preservation.
You normally have to have large preparations to do onlays. However, after the onlay is in, it reinforces the remaining tooth structure. |
|
|
Term
Which is not a desirable characteristic of impressions?
Accuracy
dimensional stability
Elastic recovery
hydrophobicity
strong tear strength |
|
Definition
| hydrophobicity. We need the impression material to by hydrophilic. |
|
|
Term
| What type of acid do we use to to etch teeth? |
|
Definition
| Phosphoric acid in gel form |
|
|
Term
| What are itera and lava used for? |
|
Definition
| Taking digital impressions. Cerec does this too. These can tell the CAD/CAM how to shape it's cast |
|
|
Term
2 part T/F
1. Food impaction is more common in ceramics than composite cerec onlays
2. You should etch the portions of a ceramic onlay that will come in contact with the tooth. |
|
Definition
| Both True. 1- This is caused by higher failure rate of the ceramics to establish regular proximal contact when compared to composite. 2- etching provides and irregular surface that will bind much better. |
|
|
Term
| Which substance allows for a better bond at the hybrid layer in ceramic-enamel interface? |
|
Definition
| Silane-silanes are used as coupling agents to adhere glass fibers to a polymer matrix, stabilizing the composite material. In other words, silane coats the glass fibers to create better adhesion to the polymer chain. |
|
|
Term
| Why is it counterproductive to etch dentin longer than 10-15 seconds? |
|
Definition
| Because it will dehydrate the collagen. Collagen, without water, doesn't perk up and binding strength is diminished. This also explains why we wet the dentin. |
|
|
Term
| What are the two most frequent problems in restorative dentistry for composites? |
|
Definition
| Secondary caries and restoration fracture. |
|
|
Term
| Elderly populations are more susceptible to ___________ caries. It is important that these are restored with (Malleable /or/ polishable) materials. |
|
Definition
|
|
Term
| Why use fluoride varnishes? |
|
Definition
| Fluoride will form a shield around the tooth of fluoroapatite, which is less susceptible to dissolvation under acidic conditions than our natural enamel. |
|
|
Term
| What purpose do sodium alginate and methylcellulose provide to toothpaste? |
|
Definition
| They are colloidal binding agents. They help keep everything together over time. They maintain homogeneity. |
|
|
Term
2 part T/F
1. Preservatives prevent breakdown of flavoring agents by catalase.
2. Abrasives help remove plaque, stain, and calculus. |
|
Definition
1 False- Preservatives main goal is to inhibit bacterial growth.
2- True |
|
|
Term
| What substance in toothpastes acts to reduces surface tension and enhance removal of debris from the tooth? |
|
Definition
| Sodium lauryl sulfate (a detergent) |
|
|
Term
| What are the two determinants of fluoride uptake in teeth? |
|
Definition
| the concentration of fluoride, and the exposure time of fluoride to the tooth. |
|
|
Term
| Tarter control has the addition of which important element? |
|
Definition
| Pyrophosphates, which are designed to retard apatite crystal growth in calculus. This can help control perio problems |
|
|
Term
| Some toothpastes are incorporating peroxides. Why? |
|
Definition
| To aid in whitening teeth. |
|
|
Term
2 part T/F:
1. Surfactants aren't used in mouthwash
2. Those with gum infections and gingivitis should choose a chlorhexidine over a fluoride mouthwash |
|
Definition
1- False, you still need a surfactant
2- True- chlorhexidine is a strong antibacterial. |
|
|
Term
Which is a better method of dealing with pit and fissures:
1: Chemical Therapeutic applications and hygeine
2: Mechanical stoppage |
|
Definition
2. Mechanical stoppage.
Often hygeine procedures and therapeutic agents just can't provide the same prevention that sealants do. |
|
|
Term
| What is the most common resin sealant? |
|
Definition
| Bis-GMA resin, which are more flowable than glass ionomer sealants. |
|
|
Term
| Mixing a solution of resin and peroxide, with a resin and amine mixture confers what property? |
|
Definition
|
|
Term
| Which will have better wear resistance, flowable composites or your run in the mill resin sealant? |
|
Definition
| Flowable composite due to the filler level, which, although it is low in flowable composites, is still higher that the filler level or resin sealants. |
|
|
Term
| What is the powder used in glass ionomer cements? |
|
Definition
| Ion-leachable fluoroaluminosilicate glass. |
|
|
Term
| Polymethacrylic acid is used in which restorative material |
|
Definition
| It is the liquid portion of glass ionomer cements |
|
|
Term
| Explain how Glass Ionomer cements set. |
|
Definition
| The aluminum and Calcium from the powder will form bridges with the acids that were present in the aqueous solution |
|
|
Term
| How do Glass ionomer cements adhere to tooth structure? |
|
Definition
| The calcium in hydroxyapatite cross-bridges (chelates) with GIC (glass ionomer cement) ions |
|
|
Term
2 part T/F
1. The full setting of Glass ionomer is 24 hours
2. The ionomer cement should be finished no sooner 48 hours after placement. |
|
Definition
1. False- it takes 48 hours to fully set
2. False- You can finish after 24 hours |
|
|
Term
| Which cavity type is a more ideal place to put glass ionomer cements: Class I, II, IV, or V? |
|
Definition
| Class V- GIC doesn't have suitalbe load-bearing strength and is opaque, so it shouldn't be used on Class I, II, or IV |
|
|
Term
| Which type of filling materials are implicated for each of the caries classes? |
|
Definition
|
|
Term
| What is synonymous with the term "hybrid ionomer"? |
|
Definition
| Resin-Modified Glass Ionomer |
|
|
Term
Which isn't true of RMGI compared to GIC:
-RMGI Set quicker
-Higher flexural strength
-Improved mehanical and physical properties
-Improved esthetics
-Fewer S. mutans exist adjacent to RMGIs
-RMGI, but not GICs are dual cure |
|
Definition
| -Fewer S. mutans exist adjacent to RMGIs. This describes GIC |
|
|
Term
2 part T/F
1 RMGI have powder and liquid.
2 The liquid is like GIC liquid, but it has resin monomers, polyacids, and water. |
|
Definition
|
|
Term
| Compomers do have an acid base reaction, but this doesn't occur until placement even though they are a single paste capsule system. Why? |
|
Definition
| Because there is no water in the compomer. Once water is available the acid-base reaction will take place. NOTE: The major setting is photo-activated polymerization. |
|
|
Term
Which is the only one below that binds to teeth without bonding agent?
-Compomer
-GIC
-RMGI |
|
Definition
|
|
Term
2 part T/F
1 Fluoride releasing capacity is typically inversely related to flexural strength of the restorative material.
2 Some studies actually show that RMGI absorb and release more fluoride than traditional GICs. |
|
Definition
|
|
Term
| How do mouth protectors work? |
|
Definition
| They distribute the energy of blows uniformly across the arch, so that one tooth doesn't get all the force at once. |
|
|
Term
| What temperature water should you use when cleaning the mouth guard? |
|
Definition
| Use cold water so the mouthguard doesn't deform. don't use abrasives or alcohol |
|
|
Term
| What type of bond is between "mer"s in a polymer? |
|
Definition
| a covalent bond, usually carbon-carbon |
|
|
Term
You have Bis-GMA and you want it adheres will to polymer X. Which is more likely polymer X?
1. n-CH3CH2CH2OH
2. n-CH3CH2CH3 |
|
Definition
| 2. n-CH3CH2CH3- which is hydrophobic will bind to Bis-GMA, which is also hydrophobic |
|
|
Term
The following pattern of a polymer represents what type of distribution?
A-B-A-B-A-B-A-B |
|
Definition
| Alternating. Others include random (statistical), block (AAABBBAAABBB) and graft |
|
|
Term
|
Definition
| Polydisperity arises because not all the polymers are of identical molecules, so some polymerization molecules are bigger than others. You can measure this by the weighted average over the total average mass. |
|
|
Term
Which of the following words means the following: coiled irregular shape of polymer chains:
Amorphous polymer
Semicrystalline polymer |
|
Definition
| Amorphous. Semicrystalline are polymer domains with regular structure acting as cross-links. |
|
|
Term
| Which is most likely to decompose when heated: linear polymers, branched polymers or cross-linked polymers? |
|
Definition
| Cross-linked. These are not able to reshape after they have been heated and will remain insoluble in organic liquids. |
|
|
Term
| What is the word that describes the ability for linear and branched polymers to allow flow and reshaping upon heating? |
|
Definition
|
|
Term
| Many shoes are are vulcanized. what qualities does this confer to the shoes? |
|
Definition
| Rubber, like elastic recover under low strain. This is the reaction of linear macromolecules are bridged by limited polymerization and this allows for elastomer creation, which act like rubber. |
|
|
Term
| Gutta percha and natural rubber is made from 2-methyl-1,30butadiene what is the difference between these two? |
|
Definition
| Gutta percha is trans, while natural rubber is the cis version of poly(1,2-isoprene) |
|
|
Term
| Which has higher molecular weight, addition polymerization, or step-growth polymerization? |
|
Definition
| Addition polymerization typically result in higher weight molecules. |
|
|
Term
Which isn't a quality of addition polymerization:
-it is fast
-it is hot
-High molecular weight polymers are formed
-Uses 2 functional groups |
|
Definition
-Uses 2 functional groups
This is an important characteristic of step-growth polymerization |
|
|
Term
| What are the three types of addition polymerizations? |
|
Definition
| Free-radical (unpaired electron on carbon), cationic (acid, positively charged) and anionic (nucleophile, negative charge) |
|
|
Term
| What are the two types of step-growth polymerization? |
|
Definition
| Polycondensation and polyaddition |
|
|
Term
| What is initiation/induction in terms of radical polymerization? |
|
Definition
| When you have an initiator-initiator complex that is broken up into two initiators, both having an electron radical that will attach double bonds of monomers. |
|
|
Term
|
Definition
| Where the initiator-"mer" radical will elongate to generate a new active center. |
|
|
Term
| When a radical meets another radical and they form a sigma bond with the two radical electrons, what is this termed? |
|
Definition
|
|
Term
Which isn't true of Methyl methacrylate polymers?
-Easy to shape
-It is fairly rigid, strong, and wear resistant
-Poor color retention
-biocompatible |
|
Definition
| -Poor color retention. MMA is very similar to tooth tissue translucency and color. |
|
|
Term
| What is % of polymerization contraction of MMA? |
|
Definition
|
|
Term
| Is MMA soluble in water or organic solvents? |
|
Definition
| Only organic solvents, not water |
|
|
Term
| What is the term for a molecule that will rapidly react with radicals to form stable compounds, thus halting propagation. |
|
Definition
|
|
Term
| What is the difference between and inhibitor and a retarder? |
|
Definition
| The avidity and speed at which they react with radicals to stop polymerization |
|
|
Term
Which isn't a reason to add inhibitors into a polymerized substance?
1 to extend shelf life of products
2 to decreases sensitivity to ambient light
3 to prevent luting
4 To prolong working time |
|
Definition
| 3 to prevent luting. This answer has nothing to do with polymerization |
|
|
Term
| Cross-linking PMMA helps to improve hardness and stiffness, does it also increase crazing? |
|
Definition
| No, it increases the wear and solvent resistence, although brittleness in increased. |
|
|
Term
| Which is easier to do 1 polish a non cross-linked PMMA or 2 polish a cross-linked PMMA? |
|
Definition
| It is easier to polish a cross-linked PMMA, which will have increased thermal resistance. |
|
|
Term
| Why would you add a plasticizer to a PMMA? |
|
Definition
| If you wanted to decrease the stiffness of a polymer, or make it flexible. |
|
|
Term
| During what procedure is it important to use dual cure polymers? |
|
Definition
| when performing a core build up, which are deeper than 2 mm deep. |
|
|
Term
| What role do regulators play in polymerization? |
|
Definition
| They decrease the rate of polymerization heat release |
|
|
Term
| Is PMMA in the powder or liquid usually? |
|
Definition
| It is usually in the powder. MMA monomers are in hte liquid, with cross-linkers, inhibitors, accelerators and UV absorbers |
|
|
Term
| List accelerators of chemically activated resins. |
|
Definition
Tertiary aromatic amines
Barbituric acid
Sodium toluene-sulfinate
Copper ions. |
|
|
Term
| When you compare heat activated to chemically activated resins, what will you see in the chemically activated resins? |
|
Definition
| Less color stability, lower molecular weight, higher amount of free monomer. |
|
|
Term
| What is the name of the magical light activated molecule that is responsible for light cure polymerization? |
|
Definition
|
|
Term
| Would you rather see bioactivity in a ceramic crown or a dental implant? |
|
Definition
| In an implant, this bioactivity is highly desirable (provides interlock or bonding to bone). If a crown is bioactive, it is probably due to inflammation. |
|
|
Term
| If you are near the pulp will there be a higher number of tubules per square mm or will the tubules be bigger, or both? |
|
Definition
| Both the tubules enlarge and get closer together as you near the pulp |
|
|
Term
| The tubules are filled with ______________ ____________ of cells that are inside the pulp. |
|
Definition
|
|
Term
| What is the change in tubular diameter between the DEJ and the pulp? |
|
Definition
| From .5 micM at the DEJ to 2.5 micM at the pulp |
|
|
Term
| What is the difference in tubule density from the DEJ to the pulp? |
|
Definition
| 20k/mm2 at the DEJ to 50k/mm2 at the pulp |
|
|
Term
| Pulpal hypersensitivity is due to what? |
|
Definition
| Positive or negative displacement of the serum-like fluid that resides in the dentinal tubules. |
|
|
Term
| What is the major component of organic material in the dentin? |
|
Definition
| Collagen (85%), The rest is osteocalcin and osteopontin |
|
|
Term
| What are the inorganic percentages of enamel v Dentin? |
|
Definition
| Enamel is 96% while dentin is 70% inorganic. |
|
|
Term
| What are the only substances that are permeable to the enamel? |
|
Definition
| Peroxides (that is why you can get bleaching related hypersensitivity) |
|
|
Term
| According to the biocompatibility, what is the proper way to get rid of the smear layer? |
|
Definition
| 37% phosphoric acid for 5 seconds. |
|
|
Term
| What is the hybrid layer made out of? |
|
Definition
| collagen from the dentin with adhesive resin. |
|
|
Term
| What is the difference between fluid convection and diffusion through the dentin? |
|
Definition
| convection is when fluid goes through tubules, whereas diffusion is related to dentin thickness as ions move through a diffusion gradient through the dentin material. |
|
|
Term
| If you get a cavity liner, sealer, or bonding agent placed on top of dentinal tubules, what would you see a more drastic reduction: convection or diffusion? |
|
Definition
| Convection- the tubules have been occluded. |
|
|
Term
| Which are more primarily composed of compact bone, long or short bones? |
|
Definition
| Long bones. Short bones are primarily spongy bone, covered by compact bone. |
|
|
Term
| What is the result of stress-shielding? |
|
Definition
| loss of bone. This is what occurs when astronauts go to space and come back with osteoporosis. |
|
|
Term
| Why is it important that epithelial cells attach to implants? |
|
Definition
| So that inflammatory issues in the mouth and gingiva don't continue downward causing periodontal disease. |
|
|
Term
| What is the name of the inflammatory disease where bacteria attach to implants and exist near the gingiva causing infection |
|
Definition
|
|
Term
| What are the pros and cons of in vitro, in vivo, and usage tests? |
|
Definition
|
|
Term
| What are the two types of cells used in in vitro tests? |
|
Definition
| Primary cells and cell lines. Primary cells are those coming directly from the subject, cell lines come from immortalized ever-growing and standardized cells. |
|
|
Term
| What are the pros and cons with using primary cells? |
|
Definition
Pro: They are more like the cells that will be targeted with the therapy. (relevant)
Con: They are not helpful when doing comparisons among studies (less consistant) |
|
|
Term
| What can you to to turn primary cells into an immortalized cell line? |
|
Definition
| Add a carcinogen like benzene, or expose it to UV light. these could destroy division regulation and cause immortalization. |
|
|
Term
| What cytotoxic test results would you expect from a product that passed the test? |
|
Definition
| Numerous cells stained for live cell stain and few cells stained with the dead cell stain. |
|
|
Term
|
Definition
| Create pores. A porogen that Xu introduced in class was Mannitol |
|
|
Term
| What test uses a dentin disc with an influx and efflux of cells on the opposite side of the disc as the dental material? |
|
Definition
| The Dentin Barrier test. This measure is important in predicting the biocompatability with the pulp. You want the cells to live that are on the opposite side of the dentin disk as the material in quesiton. |
|
|
Term
| Does testing negative in genotoxic tests mean that a material is not carcinogenic? |
|
Definition
| NO! It could cause epigenetic mutations, or the agent itself may not be carcinogenic but may cause cancer when it is in a fibrin form |
|
|
Term
| What is the major difference between animal tests and usage tests? |
|
Definition
| That the material isn't being used in the exact regard to its final use during animal tests, but it must be during usage tests. |
|
|
Term
Which isn't a cost of animal testing?
-They are expensive
-They are time consuming
-Uncertain relevance
-Results are often not repeatable |
|
Definition
| -Results are often not repeatable. The other answers were all good description of the cons of animal tests. |
|
|
Term
Which is a sign that is indicative of implantation success?
1 apical radiolucency
2 Mobility
3 osseous integration
4 fibrous capsule |
|
Definition
| 3 osseous integration. We want the implant to be integrated into the bone. Fibrous capsules indicate that the implant is being treated as foreign. |
|
|
Term
Do the following characteristics describe slight, moderate or severe dental pulp irritation?
increase in inflammatory cels, hyperemia, slight disruption of odontoblastic zone. |
|
Definition
|
|
Term
| How do you perform a dental pulp irritation test? |
|
Definition
| Place the material in a class 5 cavity prep and leave it there for 1-8 weeks. |
|
|
Term
| What is the major difficulaty of mucosa and gingival usage tests? |
|
Definition
| Pre-existing inflammation. Usually you perform a subgingival cavity prep and bacteria can get in. For this reason it is important to perform a prophylaxis and wait 8-14 days before the test. |
|
|
Term
| Sealing with which compound caused less pulpal irritation and more dentin bridging? |
|
Definition
|
|
Term
| How deep can acid get through dentin? What is the effect on pulpal inflammation? |
|
Definition
| It can penetrate under 100 micM. Acid acting on pulp coulc cause inflammation for 8 weeks or less. |
|
|
Term
Bonding can cause cytotoxic effects. Which of the following is more cytotoxic?
1 HEMA
2 Bis-GMA |
|
Definition
| 1 Bis-GMA- which is hydrophobic. |
|
|
Term
| When will amalgam cause pulpal reaction? |
|
Definition
| When it is in deep, unlined cavities. This is why you should line cavities with less than .5-1mm of remaining dentin thickness. |
|
|
Term
| Is the fluoride release of glass ionomers cytotoxic? |
|
Definition
| Yes and no. It is not cytotoxic in vivo, where it plays a role as caries inhibitors, but it is cytotoxic in vitro. GIC are very mildly cytotoxic. |
|
|
Term
| What are the two main actions of calcium hydroxide that make it a good pulp capper? |
|
Definition
| It causes coagulation of pulp hemorrhage (reparative dentin bridge forms adjacent to CaOH2), and it is bacteriocidal with a high pH. |
|
|
Term
| This agent has been claimed to potentially cause estrogenic reactions, although such claims seem doubtful. |
|
Definition
|
|
Term
| What is the only issue of biocompatability in casting alloys? |
|
Definition
| It contains nickel, so those with nickel allergies (10-20% of females) react. |
|
|
Term
| Titanium implants have thin film of __________ that prevents corrosion and allows for osseointegration. |
|
Definition
|
|
Term
What is the main source of adhesion between tooth and adhesive?
Chemical
Mechanical
Physical |
|
Definition
|
|
Term
What is the chief type of bonding that holds the adhesive and the restorative material together:
Chemical
Mechanical
Physical |
|
Definition
|
|
Term
| What is the main way that primer increases adhesion? |
|
Definition
| It increases the surface energy of the tooth by removing water from the surface |
|
|
Term
| In which system of etchant, primer, bonding is the smear layer not taken off? |
|
Definition
| In self-etch systems where the etch and primer (with or without bonding) are used in one. |
|
|
Term
| In which adhesive scheme is post-operative sensitivity less? |
|
Definition
| Self-etch systems because the smear layer will block the tubules. |
|
|
Term
| Where does bonding happen in enamel? |
|
Definition
|
|
Term
| Where does bonding happen in dentin? |
|
Definition
| In the intertubular dentin forming a hybrid layer, not in the tubular resin tags! |
|
|
Term
| What are the five requisites of bonding? |
|
Definition
| Cleaning adherend, good wetting, intimate adaptation, bonding, good curing |
|
|
