Midterm Exam Review Flashcards
What is an Inlay?
-does not include any cusps
-involves the proximal surface and occlusal surface
-stronger than a resin/amalgam restoration
- can be made out of metal (gold or porcelain
-placed in posterior
What is an Onlay?
- cusps are involved
-involves atleast one cusp, and most of the occlusal surface
-stonger than a resin/amalgam restoration - can be made out of metal (gold or porcelain)
-placed posterior
What is the main difference between an Inlay and Onlay?
Inlay does not include any cusps
Onlay involves atleast one cusp and most of the occlusal surface
What is a Veneer?
a thin shell of a tooth-coloured material. Used to improve esthetics due to chipping, excessive wear, heavy staining, close diastema spacing
What are the 2 types of veneers available?
Direct veneer - created directly in the patient’s mouth by applying resin material to facial surface
Indirect Veneer - created in the dental laboratory on the basis of an impression taken of the prepared tooth. PORCELAIN material is used, NOT resin
What is a Crown?
-indirect restorations that replace severe damaged tooth structure due to decay or fracture.
- often done after root canal treatment.
- cemented permanently into place and cannot be removed by the patient
-provides full coverage, adds strength to teeth
What are the 3 types of crowns?
Full Crowns (completly covers tooth)
Three-quarter Crown
Porcelain Fused to Metal (PFM)
When is a full crown used?
When a tooth has decay so severe, or a fracture that reconstruction can not be preforme dwith the use of a direct restoration
What is a three-quarter crown?
Covers the anatomic crown of a tooth but facial or buccal portion is unchanged
What is a PFM Crown?
- full metal crown with outer surfaces covered with a layer of procelain (for esthetic reasons) and inner layer covered with metal
-metal is added for strength and to prevent crown from fractures ue to heavy mastication
What is a bridge?
- an indirect restoration that replace either one or multiple teeth that are missing within the same quad or sextant
-consists of a series of units joined together for greater strength
-cemented permanently into place and cannot be removed by patient
What are the three components of a fixed bridge?
Unit
Pontic
Abutment
What is the Unit of the bridge described by?
The unit of the bridge is described by the total number of teeth involved in the fabrication
What is the Pontic of the bridge?
The missing tooth/artificial tooth is referred to as the Pontic
What is the Abutment of a bridge?
The tooth anchoring the bridge is referred to as the abutment.
- tooth must be stable enough to withstand bridge forces
How is the Abutment tooth prepared?
Outer layer of enamel will be removed, tooth will be reduced in size all circumference (all directions) by use of dental high-speed handpiece and bur.
What is a cantilever bridge?
-does not have an abutment on one end
-various materials can be used including metal/gold porcelain
What is a maryland bridge?
-consists of a pontic with wing like extensions from the mesial and distal sides on LINGUAL
-bonding of extensions to the lingual surfaces of the adjacent teeth supports the point.
-various materials can be used including metal, gold, or porcelain
What is an implant supported indirect restoration?
refers to artificial “root” replaced with the titanium component.
-titanium is anchored surgically into the bone.
- incorporates principles from both fixed and removable prosthodontics in conjuction with the use of bone-anchored implants
What are Endosteal implants?
- implant is surgically placed into the jawbone
-for one or more prosthetic teeth
-typically used for patients requiring a crown, bridge, or partial and full denture
What is a Subperiosteal implant?
is a metal frame that is palced under the periosteum and on top of the bone
- NOT placed into the bone
- indicated for patients who do not have enough alveolar ridge remaining
What is a Transosteal implant?
is inserted through the inferior border of the mandbile and into the edentulous area
- primarily used in patients with severely resorbed ridges
This describes a stable tooth to support the bridge
Abutment
This word is used when describing the number of teeth involved in the bridge
Unit
This restoration is offered to close the gap between the teeth - it calls itself the fifth wheel
cantilever
This restoration is offered to close the gap between the teeth
maryland
This describes a missing tooth within the bridge
pontic
This type of restoration is offered when cusps are involved
onlay
This type of restoration is offered when cusps are not involved
inlay
This tin shell of tooth-coloured material witll be placed on anterior teeth
veneer
when entire tooth is reduced in shape, dentist will call this restoration a ____
crown
Is an impression a negative or a positive reproduction?
An impression is a negative reproduction
Which of the three classifications of impressions is used for occlusal relationships?
The bite registration is used for occlusal relationships
Which type of impression tray covers half the arch?
A quadrant tray covers half the arch
Which type of tray allows impression material to lock on mechanically?
A perforated tray allows the impression material to lock on mechanically.
Which type of tray is designed to fit a specific patient.
A custom tray is designed to fit a specific patient
What is used to extend the length of a tray?
Utility wax is used to extend the length of a tray
What is the most widely used irreversible hydrocolloid for preliminary impressions?
Another name for irreversible hydrocolloid is alginate.
What is the organic substance within hydrocolloid materias?
The organic substance within hydrocolloid is alginate, which is derived from seaweed/
Why would you select a fast set alginate over a normal-set alginate?
You would select a fast-set alginate if the patient had a strong gag reflex.
What is the water-to-powder ratio for taking a maxillary impression?
The water-to-powder ratio for taking a maxillary impression is three scoops of powder to three measures of water.
Do you mix irreversible hydrocolloid on a paper pad or in a mixing bowl?
Irreversible hydrocolloid is mixed in a rubber mixing bowl.
Before an impression is taken with *reversible hydrocolloid, where is the material kept?
Before an impression is taken with reversible hydrocolloid, the material is kept in a conditioning bath.
Is an elastomeric material used for preliminary impressions or final impressions?
Elastomeric material is used for final impressions.
In which three forms are elastomeric materials supplied?
Elastomeric materials are supplied as light-bodied, regular, and heavy-bodied.
What technique is used to place light-bodied material placed around a prepared tooth?
A special syringe, or extruder, is used to place light-bodied material.
What impression material will the dentist first apply to a prepared tooth—the heavy-bodied or the light-bodied form?
The dentist first applies the light-bodied material to the teeth.
What system completes the mixing of final impression material for you?
An automix system completes the mixing of final impressions.
What is another term for polysulfide?
Another term for polysulfide is rubber base.
What type of tray is used when ZOE bite registration paste is applied?
A gauze bite tray is used when ZOE bite registration paste is applied.
Do you cool or warm the wax before placing the tray in the patient’s mouth for a bite registration?
You warm the wax to soften it before placement in the patient’s mouth.
A(n) __________ is a gel or sol substance with its particles suspended in a water-based medium.
colloid
_____ is the process of using the fingers to acheive a closer adaptation of the edges of an impression.
Border molding
A(n) ______ impression material has flexible properties and is made from rubber.
elastomeric
A foundation or main ingredient of a material is the _______.
base
To have something _______ is to have it aligned, such as the maxillary teeth centered over the mandibular teeth.
centric
______ is a gelatin-type material derived from seaweed found in reversible hydrocolloid material.
Agar
Irreversible Hydrocolloid vs. Reversible Hydrocolloid?
Reversible hydrocolloids change from a liquid to a gel-like consistency through physical means, while irreversible hydrocolloids change through a chemical reaction. Both are types of impression material used in dentistry.
___________ is the loss of water, which causes shrinkage
syneresis
______________ is a way of bringing a material to a desired temperature and consistency.
Tempering
_____ describes a property of fluids with a high resistance to flow.
viscosity
______ is the material of choice in dentistry for preliminary impressions.
Alginate
_______ is to transform a material from one physical state to another.
Hysteresis
A(n) ____________ is a reproduction of someone’s bite with the use of wax or an elastomeric material.
Occlusal registration
A(n) ________ is a substance that modifies or increases the rate of chemical reaction.
catylyst
____ is the absorption of water, which causes an object to swell.
Imbibition
If a patient has periodontal disease, but good dental hygiene habits. Are they a canditate for prosthodontics?
NO, because of the patients periodontal disease
How many appointments are commonly required for a crown or bridge?
2 Appointments
What is the difference between an onlay & a three-quarter crown?
An onlay covers most of the occlusal and proximal surfaces (involves atleast 1 cusp)
A three quarter crown covers other surfaces such as the facial or buccal surface
How does a dentist convey to a dental laborartory technichian the type of crown or bridge theat they should be making?
Laboratory prescription
What type of indirect retoration is placed to improve the appearance of the facial surfaces of the teeth?
Veneers
An impression would be considered a ________.
negative reproduction
Of the 3 classifications of impressions, which of these could be an expanded function for the certified dental assistant?
Preliminary & Bite Registration
*not final!
Of the 3 classifications of impressions, which would be used by the dental lab tech for determining occlusal relationship?
Bite registration
Which type of stock tray would be selected and prepared to cover half of an arch?
Quadrant
Which type of impression tray allows the impression material to mechanically lock on?
Perforated
Which type of tray is constructed to fit the mouth of a specific patient?
Custom
_____ would be used to extend the length of a tray to accomodate third molars.
Utility wax
The organic substance of a hydrocolloid material is ______.
seaweed
Why would a fast-set alginate be indicated when taking a preliminary impression?
The patient has a strong gag reflex
The powder/water ratio for a maxillary preliminary impression is ___________.
3 scoops of powder to 3 measures of water
Hydro- means _______.
water
Irreversible hydrocolloid material is also referred to as _______.
alginate
Irreversible hydrocolloid material is mixed in/on a/an ____________.
mixing bowl
Where would a reversible hydrocolloid material be placed prior to taking the impression?
Conditioning bath
Elastomeric materials are intended for what type of impression?
Final & Bite Registrations
How is an elastomeric material supplied?
As a paste, putty or cartridge
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
How is the light-body impression material applied during the final impression procedure?
Extruder with tip
What additional method can be used to mix final impression material instead of an extruder?
Spatula and pad
_______________ is the material universally used for taking a bite registration.
Baseplate wax
What type of tray is most commony selected when zinc oxide-eugenol bite registration material is used?
Gauze
Baseplate wax is _____________ before being placed in the patient’s mouth for a bite registration.
warmed
While the dentist is dispensing the syringe material around the prepared tooth, what should the dental assistant be doing during a final impression procedure?
Readying the tray with heavy-body material
A preliminary impression is ________ before being transported to the lab for pouring up.
rinsed, disenfected, wrapped in a moist paper towel, and placed in a precautionary bag
Where would the dental laboratory be located in a dental office?
The dental laboratory would be a separate space, away from the patient treatment areas.
What piece of equipment is used to grind away plaster or stone?
A model trimmer is used to grind away plaster and stone.
What piece of eqipment does the dentist use to determine centric relation on a diagnostic model?
A face bow is used to determine centric relation
What is the most common wax spatula size used in the laboratory?
The #7 wax spatula is used most often in the laboratory.
What is another term for a dental model?
Study cast
What dental materials are used to make dental models?
Gypsum products are used to make dental models
What are the three forms of gypsum?
The three forms of gypsum are model plaster, dental stone, and high-strength stone
What is the water to powder (g/ml) ratio of plaster?
100g of powder to 45-50 ml of water
When mixing gypsum materials, do you add the “powder to the water” or the “water to the powder”?
You add the powder to the water
What are gypsum materials mixed in ?
A specialized rubber bowl
What are the two parts of a dental model?
the anatomic parts and the art portions
When pouring an impression, where in the maxillary impression do you begin to place the gypsum material?
Near the most posterior tooth
How long should you wait before you separate the model from the impression?
45 - 60 minutes
Which of the two models (maxillary or mandibular) do you begin measuring and trimming first?
The maxillary model is measured and trimmed first
What area on the maxillary and mandibular model is trimmed different?
The anterior portion of the maxillary and mandibular model is trimmed differenlt
What should be placed between the maxillary and mandibular cast when trimming them together?
A wax bite should be placed between two models when trimming.
Of the 3 types of custom trays discussed, which technique uses a more hazardous material in the fabrication of the tray?
A more hazardous material is used in acrylic resin trays. The liquid monomer used in this tray is highly volatile.
Which type of custom tray is made for a vital bleaching procedure?
A vacuum-formed tray is made for a bleaching procedure.
Name two ways that acrylic resin can harden
Self-cure and light cure
Which type of material is used for a vacuum-formed custom tray?
Thermoplastic resin is used for a vacuum-formed tray
What is the purpose of a spacer?
A spacer is used to create room in a tray for the impression material.
How are the undercuts corrected on a model when a custom tray is prepared?
Undercuts are corrected by filling in with wax or molding material.
What type of wax could be used to form a wall around a preliminary impression when pouring it up?
Boxing wax is used to form a wall around a preliminary impression
To extend an impression tray, what type of wax?
Utility wax
What type of wax would you use to obtain a patient’s bite impression?
Bite registration wax is used to obtain a patient’s bite.
What is the most common wax used to create a pattern for an indirect restoration?
Inlay casting wax is most often used to create a pattern for an indirect restoration.
A dental material that is uniform in mixture and consistent throughout is said to be ________.
homogenous
A(n) ___________ is a dental lab machine used for cutting, grinding, and polishing dental appliances.
lathe
______ is a type of 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
A _____________ is a compound of a gypsum product with two parts water to one part calcium sulfate.
dihydrate
If an object is resistant to change in width, height, and length it is said to be _______.
dimensionally stable
The ________ is a portion of an articulator used to transfer the relationship of the upper teeth and the temporomandibular joint to a cast.
Face Bow
A(n) ______ is a compound of many molecules.
polymer
______ is a chemical process in which crystals form into a structure.
crystalization
_____ is the removal of one-half part water to one-part calcium sulfate to form the powde product of gypsum.
hemihydrate
A __________ is a replica of the maxillary and mandibular arches fabricated from an impression.
model
________ refers to the structural portion of a dental model/cast.
anatomic portion
A(n) _________ is a dental laboratory device that stimulates the movement of the mandible and the TMJ 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 to be used in the finishing of models.
slurry
Where would you commonly find the lab in a dental office?
Separate, but in proximity to the clinical operatory
Which specialty practice would have a more extensive laboratory set up?
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 the dentist use to determine centric relation from a diagnostic model?
face bow
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 is used in creating a dental model?
gypsum
Which type of gypsum is used to fabricate a replica for an inlay or crown?
die stone
The powder (g) / water (ml) ratio of model plaster for pouring a dental model is …
30 g powder / 100 ml water
When a gypsum material is mixed, how is the powder and water incorporated?
Add the powder to the water.
Gypsum materials are mixed using a(n) __________.
spatula and rubber bowl
Which of the following terms are the description of the portions of a dental model?
Anatomic / Art
Base / Teeth
When pouring up 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 rom its impression?
45 to 60 minutes
Which model (maxillary or mandibular) should you begin trimming first?
maxillary
What is the one specific area of a dental model where the maxillary and mandibular models are trimmed differently?
anterior portion
What should be placed between the two models during trimming?
wax bite
Digital models and traditional plaster models have the same advantages listed below except:
Diagnosing and treatment planning **
Same advantages:
-unbreakble
-shows a 3-d image
-accuracy
Of the 3 types of custom trays discussed in the chapter, which technique uses a volatile hazardous material?
thermoplastic resin
What type of custom tray would be made for a vital bleaching procedure?
acrylic resin
What type of wax is used to form a barrier around a preliminary impression when it is poured up?
boxing wax
What is placed to prevent a tray from seating too deeply onto the arch or quadrant?
spacer stops
What is the purpose of placing the water before putting in the alginate powder in mixing bowl?
Adding the powder to the water ensures that the powder particles are wet evenly. IF mixed in the reverse, the chemical reaction will start early with some particles setting faster than others.
Is an impression a negative or a postive reproduction of the teeth?
Negative
What type of immpression is used to record occlusal relatinoship?
Bite registration
Which type of impresstion tray covers have the arch?
Quadrant tray
What is Tisodium phosphate role within irreversible hydrocolloid?
Slows down the reaction time for mixing
The purpsoe of tripple tray impression is too….?
Record: upper occlusion, lower occlusion and bite registration
Why Dental Models Are Required?
-Diagnostic cast/mouth guards/ whitening trays
-Custom Trays
-Provisional coverage
-Orhtodontic appliances
-Visual presentation of dental treatment
What is the Art porition of a dental model?
The base - on max and mand
What is the Anatomic Portion of a Dental Model?
Teeth, Oral Mucosa, and muscle attachments
What are Dental Models?
Three Dimensional reproductions of the teeth and the surrounding soft tissue. They are also referred to as study casts
What is the reason for ginvial cord placement?
To retract gingival tissue so you can see the margins of crown
This “ ingredient” is added to alginate to prevent impression tearing apart by making the material stronger.
Potassium Alginate
This “ ingredient” is added to alginate to form a gel like consistency when the material is set.
Calcium Sulfate
This “ ingredient” is added to alginate to help you mix in 45 sec vs 10 sec, it slows down the reaction time for mixing.
Trisodium phosphate
This “ ingredient” is added to alginate to make look alginate fuller/ denser in consistency.
Diatomaceious Earth
This “ ingredient” is added to alginate to create bulk like appearance.
Zinc Oxide
Another word for AGAR is ____
Reversible Hydrocolloid
Another word for alginate is ____
Irreversible Hydrocolloid
When hydrocolloid is more liquid state it is referred to as:
Sol
You left alginate impression on the counter for a few days, alginate looks dry and did shrunk . What process appeared?
Syneresis
You left alginate impression on the counter, covered in water, wrapped in sealed plastic bag. It appears impression is twice a big now as it was before! What process appeared?
Imbibition
What do you call hydrocolloid in a rubbery or semi-hard state?
Gel
One of the reasons to take preliminary impressions is to create “precise” image of the tooth. True or False?
True
Preliminary impressions are used to make study models, whitening trays and sport guards. True or False?
True
Preliminary impression are used to make orthodontic appliances. True or False?
True
When setting up for an impression appointment, distilled water is required to mix the powder. True or False?
False
When choosing the correct tray for preliminary impressions, the following should be considered: presence of all teeth, size of the oral cavity, presence/absence of the mobile teeth, bony growth and height of the palate. True or False?
True
Utility wax is used to adapt an impression tray to accommodate anatomical variations such a high palate or bony growth ( tori). True or False?
True
Mixing alginate powder and water requires “feather like touch”. True or False?
False
Taking occlusal bite impression by using dental wax is more accurate then using polyvinyl siloxane. True or False?
False
When charting entries for recording preliminary impressions, type and size of the tray used is written. True or False?
True
Impression trays should be disinfected one at the time. True or False?
False
What are Pre-Op instructions for preliminary impressions?
What to expect during impression recording: sensation, drooling
Identify approx. time impression stays in the mouth: as per manufacture instructions
Ask patient to follow directions closely during impression taking
Explain briefly purpose of tray size fitting
What are Post-Op Instructions for Preliminary impressions?
Instruct patient to rinse with water to remove any access alginate
Provide patient with tissue to clean impression debris from around the face
Use of floss by be required to remove alginate
Patient can eat and drink right away
What patient mangement techniques can you use while recording a prelim impression?
Ask patient to lift tongue when asked (during mandibular tray seating)
Ask patient to breathe to nose (during maxillary tray seating)
Ask patient to lean forward when advised
List 3 different methods of pouring preliminary impressions.
- Double Pour
- Boxing Method
- Inverted Pour (what we do!)
What speed should be used for vibrating plate?
Turn dial to medium
Why do you need a tongue spacer for mandibular
To be able to separate tray from the stone
How long do I mix stone and water to pour anatomy portion?
Not long, just under 1 min. Mix should look thick like ice cream
Material with high amount of hemihydrate crystals will make the pour very strong. True or False?
True
Plaster products are typically classified based on their composition, with different types designed for specific uses like study models or casts. True or False?
True
When pouring gypsum anatomical part for study models, it’s important to mix the plaster to a consistency that is thick enough to allow for adequate detail capture and to avoid runniness, which could cause air bubbles or incomplete impressions. True or False?
True
Once a gypsum cast is poured, it should be left to set for a period of time before separating it from the impression to ensure a strong, durable cast. True or False?
True
Evaluating a gypsum cast includes checking for defects like cracks or incomplete areas, which should be repaired before the cast is used for any further procedures. True or False?
True
For pouring study models and casts, it’s crucial to have the proper armamentarium, including a mixing bowl, spatula, and rubber bowl for proper consistency. True or False?
True
Gypsum products should be stored in tightly sealed containers to prevent them from absorbing moisture from the air, which can interfere with their properties.
True
What material contains hemihydrate crystals.
Stone
Below types of gypsums:
Impression plaster (Type I), Model plaster ( Type II), Dental stone
(Type III) contain high amount of hemihydrate crystals. True or False?
False -
Type IV & V have higher amount of hemihydrate crystals
Can you explain the functions of trimming equipment?
Used to trim, & shape gypsum products such as stone or plaster.
What is one essential maintenance step for a model trimmer?
Water flow should be edquate to keep the abrasive wheel clean when in use.
Trimming wheel/disc may need to be sprayed and/or brushed to remove any built-up gypsum sludge
You are about the trim cast for a study model. What should you do to make your trimming easier?
It is recommended to soak the art portion (base) of the modle in a bowl of water for atleast 5 minutes. This will produce softer model/cast which will make trimming easier.
Why is “occlusal plane” important when trimming dental models?
When in occlusion, the bases of the models should be parallel to the occlusal plane
What personal protective equipment (PPE) should be worn when trimming models?
Safety glasses/sheilds, face mask, and lab coat
(NOT GLOVES)
What is one important factor to assess when evaluating an articulated study model?
Are the angle and length of each heel cuts equal on both sides of the model? Do they match the opposing model?
Did you accidentally remove any portion of tooth or any other anatomy?
What are the guidelines to trim anterior part for the maxillary model?
Trim Base
Trim Posterior borders
Trim the lateral sides
Trim heel cuts
Trim anterior borders (cut is angled from the right canine to left canine)
How are study models labeled?
Label both model/casts
include the month/day/ year impression was taken
include patients full name
write clearly and printed with permanent marker
Study models should be trimmed by following the sequence as this will produce symmetrical cast. List the order of trimming steps.
Do max first
Trim Base
Trim Posterior borders
Trim the lateral sides
Trim heel cuts
Trim anterior borders (cut is angled from the right canine to left canine)
List the steps for trimming the mandibular model/cast (done second)
-Occlude the mandibular model with the maxillary model, using the wax bite is recommended as wax will keep accurate occlusion during trimming
Trim base until it is even with the maxillary model
Trim lateral cuts
Trim heel cuts
Trim anterior borders (cut is angled from the right canine to the left canine) This part is trimmed by its self
Why would a dentist request study models?
Used to evaluate patient bite, shape of the teeth, and surrounding tissue.
What additional tools are available to help with diagnosis alongside study models?
Face bow and articulator
What are the types of impression materials available?
Preliminary - reversible (agar) & irreversible (alginate) hydrocolloid
Bite registration / occlusal - bite registration using wax or PVS (polyvinyl siloxane)
What type of impression trays are available?
full trays/ stock trays
kwik tray / sextant trays
triple tray for sextant or quadrant
To prevent impression material from peeling away from the tray during separation, what can be done?
Add adhesive to tray
Use perforated trays
Why are you looking into a mouth prior to taking an impression?
To access oral cavity health status
To determine tray sizes
Should the impression tray fit loose or tight?
Loose - we need space for impression material
Use bigger tray vs smaller
Upon reviewing CO you determined that patient has a moderate bony growth like tori present L-Q 3. To make the tray more comfortable during impression taking, what material should you use and why?
- add utililty wax to soften the tray rim
- wax is placed on lingual border of Q3
What chemical ingredient controls alginate setting time?
Trisodium phosphate - slows down the reaction time for mixing
Our current alginate does not have lots of it as we have under 45 secs to mix
What chemicl ingredient within the alginate makes the material thick?
Potassium Alginate
What chemical ingredient within the alginate prevents material from breaking apart when removing from the mouth?
Potassium titanum - provides strength
Due to patient having a strong gag reflex, what techniques should you use during appointment?
-breath through your nose, head forward, distraction, nitrous gas, drooling is normal
- do not mention gag reflex, no negative words
Explain the technique for placing impression material on a mandibular and maxillary impression tray.
Mandibular - load from lingual borders of the tray, place more anterior
Maxillary - load from back border of the tray, place more anterior
How should impression tray be seated: anterior to posterior or posteror to anterior and why?
Posterior to anterior (back to front) as this allows access material to move away not only from the gag reflex but also forms vestibular roll
Just seconds before seating maxillary tray in
your patients’ mouth, she grabs your hand and tells
you “STOP, I am not ready” What should you do?
Stop and reassure patient its going to be okay!
* you can always remix
* do not let patient remove tray when impression is
setting
Both impressions had been taken, what IPC steps
should be done prior pour and what office space will
be used to pour them?
2 methods available (with gloves or without 1 glove)
-rinse impression under cool tap water
-disinfect (follow manufacture instructions)
-rinse again under cool tap water
-follow manufactures instructions for each product
Impresson criteria for Study Models… what is a MUST?
-tray is seated fully (bone height is fully visible)
-proper extension over mandible retromolar area is present (distal of most posterior tooth recorded)
-Proper extension over maxillary tuberosity area is present (distal of most posterior tooth recorded)
-Sharp anatomical detail is present
-adequate tray size chosen
-tray is centered
-peripheral roll is present throughout
-no voids or tears interproximal
-alginate is smooth, not grainy
Dr. Lind asked you to fabricate a study models. What type of Stone Type will you
use ?
Type 1, 2 or 3.
1 and 2 may be white in appearance, less crystals and not as strong. Type 3 is yellow in color, more crystals = little more stronger)
What is Type 4 stone?
Die stone (not used by assistants, used by lab techs)
What is Type 5 Stone?
High strength stone (not used by assistants, used by lab techs)
Can you give more examples when study models
can be used?
Study models
whitening trays (base not needed)
Sports guard (1 upper impression only, thin base)
Which type of stone has an abundance of hemihydrate crystals?
die stone (type Iv)
high strength stone (type 5)
Lots of hemihydrate crystals will make the material weaker or stronger?
stronger
Little of hemihydrate crystals presence willl make material weaker or stronger?
Weaker
What are the 3 types of wax?
Occlusal / bite registration wax
Boxing wax - used with boxed pour method
Unity wax/used with impressions to extend or soften trays border
What is double pour method?
2 mixes are made
everything can be poured with this methodW
What is box and pour method?
- wax wall is made around the border
- one mix is made
-not used for study models, works for sports guards and whitening trays
What ist he inverted pour method?
1 mix is made, flipped into the base
-everything can be poured with this method
What does the anatomic portion include?
teeth, oral mucosa, and muscle attachments (2/3)
What type of wax is used to extend the impression tray or make it more comfortable?
Impression wax - utility
What does the prefix hydro mean?
Water
What type of impression tray covers half the arch?
quadrant tray
What other system completes the mixing of impression material for you?
Automix system
List the 5 kinds of gypsum products that are used in dentistry, and which one is the strongest?
Used by Dental Assistant:
Type I - Impression plaster
Type II - Dental Plaster
Type III - Dental stone
Used by Lab Tech:
Type IV - die stone
Type V - high-strength
