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DH 160 - Materials > LO 7/8 > Flashcards

LO 7/8 Flashcards

1
Q

Describe type I, type II, and type III dental cements

A
  1. Type I - luting agents that glue indirect restorations, or cement/bond ortho bands/brackets (can be permanent or temporary)
  2. Type II - provisional/intermediate restorations, dental sealants
  3. Type III - bases or liners
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2
Q

Pulpal irritation may occur due to ________

A
  1. Caries
  2. Chemicals in restorative materials
  3. Preparing the tooth (drilling)
  4. Thermal changes
  5. Forces
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3
Q

What materials are used for pulpal protection?

A

Varnishes, liners, and bases

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4
Q

Describe cavity varnish

A
  1. Thin film applied in two or three layers
  2. Seals the tubules
  3. Only used under amalgam restorations
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5
Q

Describe liners

A
  1. Used when Denton no longer covers the pulp
  2. Low strength (Calcium hydroxide)
  3. Placed only in the deepest area
  4. Direct or indirect pulp capping
  5. Stimulates tertiary or secondary dentin
  6. Provides protection for the pulp (but minimal strength)
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6
Q

Describe bases

A
  1. High strength
  2. Thick consistency
  3. Usually placed if 2 mm or less Denton covering the pulp
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7
Q

Describe insulating bases

A
  1. Protects from thermal shock
  2. Placed under metal restorations
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8
Q

Describe sedative bases

A

Soothes a pulp that has been damaged by carries or irritated during the process of decay removal

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9
Q

Describe buildup

A
  1. A thick layer of cement or restorative material used to replace missing tooth structure in a badly broken down tooth and to act a support for a restoration such as a crown
  2. Mechanical support for restoration
  3. Foundation for a cast/indirect restoration
  4. Tooth becomes reinforced with the cement buildup
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10
Q

Describe luting of indirect restorations

A
  1. Low viscosity
  2. Placed between prepared tooth and restoration
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11
Q

_______ creates one of the strongest bonds and is often used for brackets

A

Resin cement

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12
Q

How are orthodontic bands and brackets attached?

A
  1. Brackets - are bonded directly to the intact tooth surface with resin cement
  2. Bands are usually cemented without bonding
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13
Q

Because of their lower strength/wear resistance and higher solubility, cements are not frequently chosen as permanent restorations. What are the exceptions and why are they used?

A
  1. Glass ionomer cement or resin-modified glass ionomer cement
  2. Used because of fluoride releasing properties
  3. They have low film thickness
  4. They are used for class V restorations and in primary dentition
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14
Q

Describe the use of provisional (temporary) and intermediate restorative cements

A
  1. Used in emergency situations when time/scheduling doesn’t allow for permanent restoration
  2. Placed when a tooth is symptomatic or has deep caries, when waiting on an indirect resoration, or between endodontic appointments
  3. Using a sedative provisional restoration allows the dentist to evaluate the response of the pulp before permanent restoration
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15
Q

Describe the materials used in root canals

A
  1. Gutta percha - rod-like plastic material used to fill the tooth after a root canal procedure
  2. May encompass calcium hydroxide, zinc oxide, resin, glass ionomer, calcium silicate, or mineral trioxide aggregate
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16
Q

Describe the use of surgical dressings

A
  1. Protection and support to surgical site
  2. Patient comfort
  3. Controls bleeding
  4. Can be self-cured or light cured
  5. Mixed to a soft putty like consistency
  6. Form a rigid covering over the site
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17
Q

Describe the properties of type I cements: luting agents

A
  1. No cement is ideal for every clinical situation, some cements are more ideal for metal, some are more ideal for ceramic or porcelain
  2. Important to know strength, solubility, viscosity, biocompatibility, anti-carogenic properties, retention, aesthetics, radio opacity, and the ease of manipulation
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18
Q

What is important to know about the viscosity and film thickness of luting cements?

A
  1. Needs to be applied in a very thin layer - flow easily throughout the preparation or indirect restoration
  2. If too thick, the restoration will not seat properly - leading to exposed magrins and therefore cement washing away, tooth sensitivity, recurrent decay, and staining
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19
Q

Describe the biocompatibility and anti-carogenic properties cements must have with an example

A
  1. Must not cause sensitivity or pulpal necrosis
  2. Eugenol - good sealing ability antibacterial properties and neutral pH
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20
Q

Describe the retention and adhesion of a good dental cement

A
  1. Minimizes micro leakage
  2. Has good mechanical or chemical adhesion
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21
Q

Why is radio opacity important for dental cements?

A

High radio opacity will allow the cement to show when examined with x-rays so that it will not be mistaken for Carrie’s or a void. Good radio opacity will also make excess cement easier to see

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22
Q

What are the classifications of luting agents?

A
  1. Water-based luting cements - undergo an acid-base neutralization reaction
  2. Resin based luting cements
  3. Oil-based luting cements
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23
Q

Give four examples of water-based luting cements

A
  1. Zinc phosphate cement - one of the oldest, can cause hypersensitivity, pretty soluble, not used widely but sometimes under metal
  2. Zinc polycarbonate cement - often used as long-term temporary cements
  3. Traditional glass ionomer cement - high biocompatibility
  4. Resin modified glass ionomer cements - used for metal based restorations, endodontic metal posts, orthodontic bands and brackets, are stronger ceramics such as zirconia or lithium disilicate
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24
Q

_____ resin cements are low viscosity resins derived from composite resin.

A

Esthetic

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25
Q

_______ resin cements have wide applications for luting metal, ceramo-metal, and all ceramic restorations but are not used for porcelain veneers

A

Adhesive

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26
Q

While adhesive resin cements require separate bonding agents to bond to tooth or restoration surfaces, ________ resin cements eliminate the need for separate etching and priming for bonding

A

Self-adhesive

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27
Q

_______ resin cements are used to temporarily retain provisional crowns, bridges, or other indirect provisional restorations

A

Provisional

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28
Q

_______ cements are somewhere between resin cements and glass ionomer cements in their composition since they contain some of the components from each type

A

Compomer

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29
Q

Describe the oil-based luting cement zinc oxide eugenol

A
  1. Commonly referred to as ZOE cements and have been widely used for many years
  2. Generally, they do not have the strength needed to be permanent cements or high strength bases
  3. Used for provisional cementation, provisional and intermediate restorations, low strength bases, and root canal sealers and periodontal dressings
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30
Q

Describe bioactive cements

A
  1. Relatively new category
  2. Stimulate living tissue
  3. Used to stimulate reparative dentin
  4. Two categories - calcium silicate & calcium aluminate
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31
Q

What are the two categories of bioactive cements?

A
  1. Calcium silicates - pulp capping and vital pulpotomies
  2. Calcium aluminate - permanent luting agents
32
Q

What should you know about mixing cements?

A
  1. YOU MUST FOLLOW THE MANUFACTURER’S DIRECTIONS
  2. Cements are supplied in - liquid and powder, predosed capsules, syringes, auto mixing cartridges
  3. Observe proper ratios if you have to measure
  4. Pay attention to working and setting times
  5. Can be self-cured, light cured, or dual cured
33
Q

Describe zinc phosphate

A
  1. It is the oldest cement used in dentistry, but not widely used today
  2. Comes in a powder / liquid
  3. Can only be mixed on a cool glass slab because of exothermic reaction
  4. Has acidic pH which can be irritating to the pulp
  5. Highly soluble
  6. provides thermal insulation to the pulp
34
Q

Describe zinc polycarboxylate

A
  1. Adheres to tooth structures
  2. Non irritating to the pulp
  3. Easy to use, but short working time
  4. Used for final cementation of cast restorations
  5. Highly soluble
  6. Low strength
35
Q

Describe glass ionomer cements

A
  1. Chemically bonds to the tooth and metal
  2. Fluoride releasing
  3. Easy to mix
  4. Moisture sensitive
  5. Used for permanent luting agent, liner, base, restorative
36
Q

Describe resin based cements

A
  1. Adheres directly to tooth structure
  2. Can Bond all ceramic restorations
  3. Various shades available
  4. Insoluble
  5. High strength
37
Q

Describe zinc oxide eugenol

A
  1. Low strength
  2. High solubility
  3. Acts as a sedative to the pulp
  4. Easily manipulated
  5. Cannot be used in combination with resins
38
Q

What are impressions?

A

A “negative” reproduction of the mouth

39
Q

Final impression materials are used for _______

A

Crowns, veneers, etc.

40
Q

Preliminary impression materials are used for ______

A

Sports guards, whitening trays etc

41
Q

What are the three basic types of impressions?

A
  1. Preliminary
  2. Final
  3. Bite (occlusal) registration
42
Q

What are preliminary impressions with examples?

A
  1. They are used for planning other treatments - study casts
  2. Alginate is used
  3. Used to create - custom impression trays, whitening trays, sports guards, orthodontic appliances (removable)
43
Q

What are final impressions with examples?

A
  1. Produce the most accurate reproduction of the teeth and surrounding tissues
  2. Polyvinyl siloxane and polyether are most commonly used
  3. They are used to give the lab technician details on fabrication of indirect restorations, full or partial dentures etc
44
Q

What are bite registrations with examples?

A
  1. Replication of the patient’s occlusion - records the relationship of the maxillary Arch to the mandibular Arch
  2. Wax or polyvinyl siloxane is used
  3. They are used to - Mount diagnostic casts on an articulator, establish proper relation between the restoration or prosthesis and the opposing arch - casts can be made to reflect patient’s natural bite
45
Q

Describe impression trays

A
  1. Can be stock or custom
  2. Used to carry the impression material to the mouth
  3. Support the impression material until it has set
  4. Supports the gypsum when poured
  5. Must be rigid to prevent distortion
  6. There are a variety of trays to choose from depending on the impression being obtained
  7. Periphery wax may be used to adopt the periphery of the tray - make it less painful on soft tissues
46
Q

Describe custom impression trays

A
  1. Custom fit to the patient
  2. Made in the lab - chemical cured material, light cured material, thermoplastic resin
  3. Created on casts of the teeth
47
Q

Describe bite registration trays

A
  1. A plastic frame with thin fiber mesh stretched between the sides of the frame
  2. The mesh retains the impression material and is thin enough not to interfere with closure
  3. The patient closes in centric occlusion until the material is set
  4. Can be used for final impressions - triple tray
48
Q

What is a triple tray?

A

It is a type of bite registration tray that is used to make an impression of the teeth being treated and the opposing teeth at the same time. If used properly, it will capture the correct centric occlusion of the patient. Used for final impressions

49
Q

What are the three types of impression materials?

A
  1. Elastic - hydrocolloids (agar and alginate), elastomers
  2. Digital
  3. Inelastic - impression wax, impression plaster, zinc oxide eugenol
50
Q

What are the three key properties of impressions materials?

A
  1. Accuracy - must adopt and flow over the teeth etc
  2. Tear resistance - prevents tearing when removed from the mouth
  3. Dimensional stability - must remain stable so that casts and dies are accurate
51
Q

Describe hydrocolloids

A
  1. Hydro=water; colloid=gelatinous
  2. Changes from a sol (solution) to a gel (solid or semi-solid)
  3. Elastic impression materials
  4. Some materials are hydrophobic and some are hydrophilic
52
Q

Agar hydrocolloid is _______

A

Reversible

53
Q

Alginate hydrocolloid is _______

A

Irreversible

54
Q

Describe reversible hydrocolloids

A
  1. Can go from a solution to a gel to a solution if needed
  2. Done by means of heating the materials to bring them to a solution to place them in impression trays
  3. Materials thicken and becomes a gel
  4. If the impression is not adequate, the material can be heated again to bring it to a solution to retake the impression
  5. Not used much today
55
Q

Describe irreversible hydrocolloids

A
  1. Alginate
  2. Cannot return to a solution after it becomes a gel
  3. Chemical reaction between the water and powder
  4. Not accurate enough for making crowns, onlays, etc - does not capture fine details
  5. Thick and doesn’t flow well
  6. Derivative of seaweed
56
Q

What two issues is the completed impression sensitive to?

A
  1. Synerises - moisture loss causes the impression material to shrink
  2. Imbibition - moisture saturation causes the impression material to expand
57
Q

What is the proper way to handle an impression right after taking?

A
  1. Rinse under running water
  2. Disinfect with a spray-sodium hypochlorite and water for 3 minutes
  3. Rap in a moist paper towel and place in a zippered plastic bag labeled with a client’s name
  4. Should be poured within an hour - it is dimensionally unstable
  5. Must be rinsed thoroughly prior to pouring
58
Q

Describe an acceptable alginate impression

A
  1. All teeth and alveolar process included
  2. Peripheral role and frena included
  3. No voids or bubbles
  4. Alginate firmly attached to the tray
  5. Good reproduction of detail
  6. Palatal vault recorded
  7. Retro molar / tuberosity areas included
59
Q

Describe elastomers

A
  1. Used as final impression materials
  2. Highly accurate and used for the fabrication of - crowns and bridges, ceramic or cast material restorations, partial and complete dentures
  3. Not sensitive to syneresis or imbibition
  4. PVS most commonly used
60
Q

Describe digital impressions

A
  1. Taken with an intraoral scanner and read using a cad/cam system
  2. Advantages - permanent 3D models, no impression materials / pouring, electronic transmission to lab
  3. Disadvantages-cost, training, limitation for small mouths
  4. Soft tissue management is required if tissues need to be retracted for scan
61
Q

Describe inelastic materials

A
  1. Wax/compound wax lacks accuracy, multiple when heated but distorts easily
  2. Impression plaster - no longer used
  3. Zinc oxide eugenol paste - rarely used
62
Q

Describe proper disinfection of impressions

A
  1. All impressions (preliminary, final, bite registrations) are considered contaminated
  2. Microorganisms can get into the gypsum and survive for 7 days - spore survive much longer
  3. Disinfection should be done chairside after removal from the mouth
  4. The disinfectant used must be compatible with impression material
63
Q

Describe proper sterilization of trays

A
  1. All metal trays must be properly cleaned and sterilized and if the tray has been tried but not used, it must also be sterilized
  2. Custom trays should be discarded
  3. Some plastic trays can withstand heat sterilization, if not specified, they must be discarded
64
Q

Describe extrinsic stains and their causes

A
  1. On the outside of the tooth surface
  2. Caused by - food and drink, poor oral hygiene with pigment producing bacteria, tobacco products, antimicrobial mouth rinses
  3. Removed by brushing, scaling, or air polishing
  4. Stubborn stains may require whitening products
65
Q

Describe intrinsic stains and their causes

A
  1. Stains within the tooth structure
  2. Causes can be pre-eruptive/during tooth development. Including: trauma to developing tooth, illness with high fever, excessive fluoride intake, certain medication
  3. Causes can be post-eruptive, including: age-related (yellowing, light brown, dark grey), endodontically treated tooth, amalgam staining, caries
66
Q

Explain how whitening works

A
  1. Enamel is composed of minerals with microscopic spaces between the rods the contain water, stains accumulate in these spaces over time and may also reach the dentin
  2. Whitening agents pass through the spaces and reach the dentin - releases oxygen that oxidizes the stains and lightens the color of the dentin, irritation may result in open carries / lesions
67
Q

What are the most widely used whitening materials?

A
  1. Hydrogen peroxide and carbamide peroxide
  2. Some products contain potassium nitrate and fluoride
68
Q

Describe home whitening (carbamide peroxide)

A
  1. Carbamide peroxide is urea peroxide and hydrogen peroxide combined
  2. 10%-44% concentrations
  3. Weaker oxidizing agent
  4. 10% carbamide peroxide is equal to 3.5% hydrogen peroxide
69
Q

What are the three methods of teeth whitening?

A
  1. In the dental office
  2. At home with a prescribed product from the dental office with professional supervision
  3. At home with over the counter whitening products without professional supervision
70
Q

Describe in office whitening

A
  1. A stronger solution is used
  2. A dental dam is necessary
  3. “Power whitening”
  4. May require a high intensity light
  5. Maybe given custom trays and whitening material to use at home to touch up after the initial treatment
71
Q

Describe whitening non-vital (dead) teeth

A
  1. The pulp becomes necrotic causing dentin to stain from blood
  2. Tooth requires endodontic treatment
  3. Once the tooth is treated, in office whutening can be done
  4. The tooth is isolated with a dental dam
  5. Glass ionomer is placed to seal the access to the canals
  6. 30% to 35% hydrogen peroxide is placed into the pulp chamber
72
Q

Describe walking bleach

A
  1. A method for non-vital (dead teeth)
  2. Done on an endodontically treated tooth
  3. Endo access is opened up
  4. Whitening gel is placed inside the pulp chamber and sealed with a temporary restoration
  5. The patient returns in 2 to 7 days
  6. The temporary restoration is removed and a permanent restoration is placed
73
Q

Describe home whitening prescribed by the dental office

A
  1. 10% to 45% carbamide peroxide or 6% to 15% hydrogen peroxide is used
  2. Some have potassium nitrate added
  3. Preliminary impressions are taken and custom whitening trays are fabricated
  4. Whitening usually takes 2 to 4 weeks and product is most effective in the first two to four hours
  5. Patient returns to have shade checked
74
Q

Describe the procedure for home whitening

A
  1. Appointment one - intraoral assessments, obtain consent, record clients tooth shade using natural light and shade guide, select impression trays, take mandibular and maxillary alginate impressions, disinfect impressions, bring to lab, pour impressions using dental stone, fabricate trays
  2. Appointment two - insert trays to ensure proper fit and comfort, demonstrate loading tray with gel, transition, and removal of excess gel, provide verbal and written instructions following manufacturers instructions, schedule a follow-up appointment in 2 to 3 weeks
75
Q

What are the contraindications for whitening?

A

Allergy to the products, pregnancy or nursing, open carious lesions, cracked enamel, restorations on front teeth, actively leaking restorations, sensitive teeth, use of meds causing photosensitivity, inability to follow directions, unrealistic expectations, under the age of 15

76
Q

Describe the over-the-counter whitening products available

A
  1. Whitening strips - 10% peroxide gel
  2. Paint on - often washes off with saliva
  3. Tray whitening - 10% to 22% carbamide peroxide
  4. Whitening toothpaste-remove surface stains, use a silica or calcium carbonate abrasives
  5. Rinses- hydrogen peroxide

DH 160 - Materials (8 decks)

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