Fixed Boards Flashcards
a prerequisite to fixed prosthodontic treatment
Healthy joint and supporting skeletal musculature
Normal maximal opening
53-58mm
restricted opening
less than 40mm
Class I lever
Class II lever
Class III lever
Class I -see-saw - work fulcrum force
Class II - wheel barrel - fulcrum work force
Class III- nut cracker - fulcrum force work
FMA angles
Normal - 25 +- 5
low - less than 20 - increase forces
high greater than 30 - decrease forces
biologic width
2mm from bottom of sulcus to alveolar crest.
1mm is junctional epithelium and 1mm is connective tissue
Tooth tapers
-anterior teeth: 30°
-premolars: 10°
-molars: 8°
6 indications for subgingival margins
caries
pre-existing restorations
esthetics
root sensitivity
cervical erosion
root fracture
Force on pontics 1, 2, 3
the force on 1 pontic is 1X the distance
the force on 2 pontics is 8X the distance
the force on 3 pontics is 27X the distance
Seibert Classification
Class 1 - BL
Class 2 - Apicocoronal
Class 3 - combination of both
Crown to root ratio
minimal: 1:1
best: 1:2
Ante’s Law
surface area of abutments should be equal to or exceed the area of the teeth to be replaced
Irreversible hydrocolloid ingredients
- sodium alignate
- CaSO4 2H2O
- Diatomaceous earth
- Potassium sulfate
- Trisodium phosphate
- glycols
7 wintergreen - disinfectants
alginate reaction
H20 + potassium alignate + CaSO4 2H2O -> Calcium algiante gel + KSO4
Functions of anterior deprogrammer
- relax musculature
eliminate engrams
place 20-30 mins
4 indications for a collarless metal-ceramic restoration
thin gingival tissues
high smile line
exposed root surfaces
areas where gingival recession is likely
3 principles of tooth preparation
biologic
mechanical
esthetic
4 biologic considerations
- Pulpal
- adjacent teeth
- periodontal
- conservation of tooth structure
4 indications for sub gingival margins
caries
retention/resistance form
esthetics
the need to end the margin on tooth structure and not restorative material.
3 mechanical considerations
- structural durability
- the effect of mastication forces on the cement
- retention and resistance form
Retention
path of insertion or withdrawal (should restrict the possible paths)
6 retention variables
taper
diameter
height
surface area
surface roughness
effects of boxes and grooves
Resistance
prevents dislodgment in a horizontal direction (lateral forces)
3 resistance variables
taper
diameter
height
4 esthetic considerations
retainer selection
amount of reduction
contour
placement of margin
4 ways to ensure you’re taking off the required amount of tooth structure when prepping
know the diameter of your bur
make depth cuts
use a template to evaluate your reduction
prep ½ the tooth at a time
9 functions of a provisional
pulp insulator
protects the periodontium
determines gingival tissue position at the preparation margins
maintains arch integrity
acts as a “road-test” for the final restoration
confirms esthetics of the diagnostic wax-up
confirms incisal lengths and position of teeth with regards to phonetics
a means to evaluate tooth reduction
communicates form, function, and dimensions to the lab
polymethyl-methacrylate (PMMA)-Jet acrylic
high strength
best wear resistance
the most exothermic
high shrinkage
low cost
polyethyl-methacrylate (PEMA)-Snap, Trim
-moderate strength
-high wear resistance
-short term color stability
-moderate exothermicity
-moderate shrinkage
-low cost
2 advantages of custom tapered cast post and cores:
high strength with a better fit
conserves more radicular tooth structure
3 disadvantages of custom tapered cast post and cores
not as retentive
greater chance of splitting the tooth (wedge)
multiple visits required
2 disadvantages of pre-fabricated, parallel sided, dowel with core
loss of tooth structure (makes tooth fit the post)
possible corrosion with stainless steel posts
2 indications for pre-fabricated, parallel sided, dowel with core
straight canals
circular canals in x-section
How much gutta percha should remain for post and core
4/5mm
goal of tissue displacement
achieve space for impression materials both vertically and laterally.
3 types of cords
plain, braided, or knitted
Chemicals used in cords
-epinephrine
-potassium aluminum sulfate (ALUM)
-aluminum chloride (Hemodent)
-ferric sulfate
-zinc chloride
-tetrahydrozoline
3 advantages to using retraction cord
-gingival sulcus gets defined
-it acts as a blotter for heme and saliva
-prevents impression material from getting caught in the sulcus
Impression materials
-polysulfide
-condensation silicone
-addition silicone
-polyethers
-reversible hydrocolloid
7 Types of pontics
- ridge lap
- modified ridge lap
- sanitary
- bullet
- ovate
- perel
7 Porter
Hue
the name of the color (red, blue, green, etc.)
Value
the whiteness or blackness of a color
-a low value is closer to black and a high value is closer to white
-* this is probably the most important dimension to the dentist
Chroma
the saturation or intensity of the hue
metamerism
a phenomenon that occurs when 2 objects match in color under certain lighting conditions, but do not match under others. This occurs when objects have different spectral curves
responsible for interpreting brightness differences. Used for vision at low light levels.
Rods of retina
mediators of color vision
cones of retina
ideal luting agent properties
low viscosity and film thickness
long working time with rapid set
good resistance to water or acid attack
high compressive and tensile strength
adhesion to tooth structure and restorative material
cariostatic properties (fluoride release)
biologic compatibility
esthetics
5 categories of luting agents
- phosphate bonded (zinc phosphate)
- phenolate bonded (zinc oxide and eugenol)
3.polycarboxylate bonded (zinc polycarboxylate or glass ionomer) - resin composites
- Resin modified glass ionomer
3 advantages of ZnPO4
successful clinical record
low film thickness
easy to remove excess
4 disadvantages of ZnPO4
pulpal sensitivity (pH=3.0)
soluble in oral fluids (washout)
no chemical bond to tooth or restoration
it’s exothermic
2 advantages of ZOE
biocompatible with pulp
increased working time
4 disadvantages of ZOE
low strength
washout
experiences viscoelastic deformation
it’s exothermic
4 advantages of Zn polycarboxylate
low pulpal irritation
adheres to tooth
low film thickness
radiopaque
-5 disadvantages of Zn polycarboxylate
short working time
low strength
high microleakage
creep and plastic deformation
reaction is exothermic
5 advantages to GI
high strength
fluoride release
adhesion to enamel and dentin
biocompatibility
low film thickness
3 disadvantages to GI:
difficult manipulation
moisture sensitivity
can be dehydrated
4 advantages of self cured resins
high strength
low solubility
adhesion to tooth structure
low post-op sensitivity
2 disadvantages of self cured resins
high shrinkage
increased cement gap at margin
3 advantages of RMGIC
increased working time
fluoride release
bonds to tooth structure
2 disadvantages to RMGIC
lack of translucency
increase water sorption
Acron articulator
condylar elements on the lower member of the articulator and condylar paths are on the upper member. **This is anatomically correct
non-arcon
condylar paths are on the lower member of the articulator and condylar elements are on the upper member.
intercondylar distance
110mm
shear (non-functional) cusp
lingual on the mandible; buccal on the max
apexification
externally loading the condyles in centric relation
fremitus
vibration of the roots of teeth that close into contact.
engram
memorized pattern of muscle activity
crepitus
a crackling or grating noise in a joint during movement
Ways to determine VDO?
swallowing (Shannahan)
Closest speaking space (Silverman)
Ridge parallelism
Physiological rest (Niswonger)
Tactile (Lytle)
Bitefore (Boos)
Why did you use blue mouse
Initially dead soft, fast set, sets rigid, dimensionally stable, unaffected by disinfectants, can be
trimmed
What are the four methods of obtaining CR? (CR)
1) Static Recordings; Direct interocclusal records
2) Graphic recordings; started with Balkwill but Gysi first to record mandibular movement and
CR, pantograph, coble balancer (Hardy and Pleasure)
3) Functional Records: myomonitor, swallowing with compound cones, stereograph (TMJarticulator-
Swanson and Swif); chew-in Myers
4) Cephlometrics- Atwood
What are 4 ways of guiding patient? (CR)
1) swallowing (.4mm error); Shannahan (static)
2) chin point guidance (.14 error); Gnathology (static)
3) chin point w/ ant jig (.07 error); Lucia (static)
4) bimanual manipulation (.05 error); Dawson (static)
Caries definition
Infectious microbiological disease of the teeth that results in localized dissolution and destruction of calcified tissues
What bacteria for caries
Strep mutans - onset
lactobacilli - progression
Gypsum equation
Ca sulfate hemihydrate + water = calcium sulfate dehydrate + heat
Stone categories
Type 1 - impression plaster
Type 2 - model plaster
Type 3 - dental stone
Type 4 improved stone
Type 5 - high strength
PVS composition
base: dimethyl siloxane with silane groups
accelerator: vinyl terminated siloxane
Chloroplatinic acid
Filler: copper carbonate
What types of erosion are there
Rumination Erosion (6-10% in institutionalized patients)
●Bulemia Erosion: Max anterior palatal
●Alcoholics
●Citrus Fruit Erosion/Carbonated beverages: incisal 1/3 max anterior
Abrasion
wearing away of tooth through mechanical process
Erosion
loss of tooth substance by chemical processes that do no involve bacterial action
Abfraction
The cause is multifactorial, it is thought to be due to tooth flexure from biomechanical
loading forces and chemical fatigue degradation of enamel
Turner Categories of wear
1 - excessive wear with loss of VDO
2 - excessive wear without loss of VDO and available space
3 - excessive wear without loss of VDO and limited space
Celenza classification
Class I: simple holding
Class II: vertical and horizontal movement, but not related to TMJ
A: motion unrelated to pt
B: motion based on theories
C: motion based on patient
Class III: condylar pathways using average anatomic values
A: static protrusive records
B: accepts lateral records
Class IV: 3-D registrations
A: paths formed by patient (TMJ)
B: paths from settings and inserts (D5A)
Bodily shift in the mandible in the direction of the working side
Laterotrusion
Long centric
The anterior teeth should immediately disclude the posterior teeth but at a controlled angulation so that you don’t lock the patient in. The patient must have an unimpeded path to centric relation. PMS
Detrusion, surtrusion, retrusion definitions
Laterodetrusion: lat and down on working side
Laterosurtrusion: lat and up on working side; greatest effect since it brings arches closer together
Lateroretrusion: lat and back on working side
PVS composition
Base: dimethyl siloxane with silane groups
Fillers such as copper carbonate which control consistency
Accelerator: vinyl terminated siloxane Chloroplatinic acid
Alginate composition
Potassium alginate
Calcium sulfate dehydrate
K Phosphate
Na Phosphate
Diatemaceous Earth
Glycols
Gypsum classifications
Type I Impression Plaster - 15% exp
Type II Model Plaster - .30% exp
Type III Dental Stone - .20% exp
Type IV Improved stone - .10 exp
Type V High Strength, Exp - .30 exp
Specs for microstone
ISO Type 3
Brand:Premium dental stone
40ml/140g water to powder
5-7min working time 15 min set time
0.12% expansion
Compressive strength (MPA) after 1 hr 31 after 48 hr 59
Specs for mounting plaster
ISO type 1
Brand: “low expansion fast setting plaster”
63ml/100g water powder
60-90s working time 3 mins setting time
.09% expansion
Compressive strength (MPA) 1 hr 4 after 48 hrs 12
How did you program articulator for HCI and laterotrusion
HCI - protrusive check bite
Laterotrusion - Hanau formula or lateral check bite
What does UTS stand for
Universal transferbow system
