Resins are __________ used for dentures, partial dentures, maxillofacial prosthetics, reline material, tissue conditioning, repair of prosthetics, denture teeth,
polymers
What are multiple "monomer" chemically bonded together, larger/longer chain molecules?
polymer
Polymerization is the act of forming polymers using _________ bonds
carbon
What are the 2 different types of polymerization?
addition
condensation
What is the most common form of polymerization for dental materials, has three stages, and occurs when the free radical opens bond between carbon atoms of the monomer?
addition polymerization
What are the 3 different stages of the addition plymerization?
initiation
propagation
termination
The polymerization process produces ___________
HEAT
What happens of the heat from polymerization is too high?
it causes the monomor to vaporize causing porosity
The combination of what two materials causes polymerization for acrylic resins (plastics)?
liquid monomer mixed with small plymer powder
The end product of polymerization of liquid monomer mixed with small polymer powder in acrylic resins (plastics); or the polymerized resin is called what?
poly methyl methacrylate (PMMA)
What are 3 sources of dimensional change of acrylic resins (plastics)?
polymerization shrinkage
water sorption
thermal expantion
The coefficient of thermal expansion in acrylic resins is more than ________ that of composite resins
twice
Is the chemically cured or heat cured acrylic resin weaker, softer, more porous, and less color stable?
chemically cured
The chemically cured acrylic resin has more residual monomers than the heat cure, these residual monomers can cause what to tissues?
inflammation
acrylic resins that are chemically cured can undergo dimensional change in the first __________ hours
12-24 hours
What is it in polymerized acrylic resin that is characterized by the presence of many small or microscopic voids or pores?
porosity
What property of acrylic resins cause them to collect debris and microorganisms that give them stain and smell?
porosity
What is a result of loss of monomer or inadequate pressure during processing?
porosity
What property helps keep the monomer from evaporating during polymerization and creates a denser acrylic?
PRESSURE
At what pressure are acrylic monomers polymerized?
in a pressure pot at about 15-20 lbs of air
If acrylic resins are polymerized at 15-20 lbs of pressure it will result in what 3 positive characteristics for the acrylic resin?
denser acrylic
stronger acrylic
less porosity
Acrylic resins polymerize by an ___________ reaction
addition
Acrylic resins that polymerize by an addition reaction are supplied as what 2 substances? What are each of them mostly made up of?
powder: PMMA (polymethyl methacrylate) and benzoyl peroxide (the initiator)
Liquid: mainly MMA (methylmethacrylate)
Why is the liquid portion of the acrylic resin stored in dark brown bottles?
to prevent ultraviolet light from initiating polymerization during storage
Chemically cured liquid acrylic resins have ___________________ as an activator.
tertiary amine
Name and describe the 4 stages of chemically cured resins.
sandy stage: powder and liquid mixture; grainy
stringy stage: powder absorbs liquid into their surface
dough stage: more powder in solution
rubber stage: no longer can be manipulated
In what type of resin cure does polymerization occur when liquid's tertiary amine activates the benzoyl peroxide in the powder; causing free radicals to develop?
chemically cured resins
chemically-cured resin polymerization is what type of reaction? (it produces heat)
exothermic
What is the most common method for processing denture bases?
heat-cured resins: uses head and pressure during polymerization
In the heat-cured polymerization of acrylic resins, heat activates, what which causes the formation of ree radicals and allows polymerization?
benzoyl peroxide
Polymerization shrinkage is the most evident in what part of the dentures?
palatal area
What is a problem with long term soft liners that may cause them to separate from the denture base at the edges and leak between the liner and the denture base?
long-term soft liners do not form a good bond to the old acrylic
Long-term soft liners can be made from one of what 2 substances that have been made pliable by the addition of PLASTICIZERS?
silicone rubber
acrylics
The silicone liners for the use of long-term soft liners are more stable over the long term than the acrylic because they do not have softeners to leach out; however, they can be difficult to what?
adjust
Which type of long-term soft liner material support the growth of yeasts? What is a common yeast that may cause tissue irritation and requiring antifungal therapy?
silicone
candida albicans
Which type of cure for the long-term soft liner has the best physical properties?
laboratory heat-cured
cleaning long term soft liners with what type of solution will help reduce the formation of yeasts?
benzalkonium chloride
Which type of denture liners are tissue conditioners, usually performed chairside, readapt to pts tissues under NORMAL occlusion; and are applied to primed denture base; reseated in the pts mouth for border molding?
short-term soft liners (tissue conditioners)
How long do short-term soft liners usually last?
1-4 weeks
Dentures become loose over time due to what?
bony ridges resorbing
Which type of hard liner must you be careful while performing because it causes an exothermic reaction and can burn the tissue?
chairside reline
which type of hard liner is heat and pressure processed?
laboratory liner
What are they two types of material used to make denture teeth?
plastic: acrylic resin
porcelain
Which material of teeth used for denture teeth chemically bond to the acrylic base of the denture; and do NOT wear opposing natural or artificial teeth or restorations?
Plastic: acrylic resin
Are plastic (acrylic) teeth or porcelain teeth used for dentures softer and wear more rapidly, but don't stress bony ridges as much, and are more resilient?
acrylic teeth: plastic
Porcelain teeth do NOT bond to the denture acrylic and need what to hold them in?
mechanical retention
Porcelain teeth for dentures are contraindicated in what situation?
if they are coming against natural teeth, they will wear them down
Which type of denture teeth transmit heavier occlusal force which may cause pt discomfort, denture sores, and accelerate ridge resorption?
porcelain
What are 3 advantages of using porcelain denture teeth?
hard
esthetic
stain resistant
a specialized aspect of a prosthodontic practice may include the fabrication of ________________ prosthesis to replace facial tissues, lost as the result of trauma, disease, surgery, or birth defects
maxillofacial
In which type of denture repair are the pieces held together by sticky wax during the repair; plaster or stone is poured around the prostheses for stabilization; cut fracture line with acrylic bur; wet and prime roughened with monomer like chair-side reline?
chemical cured acrylic REPAIR material
What are used to establixh the proper dimension between upper and lower arches for dentures?
record bases
In homecare for dentures, they should be cleaned with a denture brush with what material? (3)
liquid soap
mild hand soap
non-abrasive denture cleaner: some commercial denture cleansors are too abrasive
Why is it important to rinse dentures thoroughly after meals?
because they need to be cleaned of debris before being placed in a denture soak
Calculus on dentures can often be softened by soaking it in what solution?
1:1 ratio of water and white vinegar
What solution should you absolutely NOT soak dentures in? Why?
undiluted household bleach
It will: fade color from acrylic
attack metal framework on partial dentures: metal will turn dark and corrode; NO commercial cleaner with bleach should be used for metal partials
true or false. Calculus will accumulate on dentures in the same places as natural dentition
true
Where are the most common areas for calculus to develop on dentures?
maxillary molars
mandibular incisors
(same as natural dentition)
Describe the 2 processes of cleaning calculus off of dentures at a DH appointment.
place in zippered bag with denture cleaning solution and place in ultrasonic cleaner
Carefully hand scale: polish with flour pumice, then tin oxide, or acrylic polishing compound
How should acrylics be stored and why? Where should they NOT be stored and why?
stored in water to keep them wet: because acrylics hydrophobic and sensitive to water loss which may cause dimmensional change
Do NOT store dentures containing soft liners in mouthwash with alcohol: it may adversely affect the properties of the soft liner
