Fixed Prosth- ABGD Flashcards
What are the implant space requirements for denture locators?
8-10 mm
Locator- 3-3.5
acrylic: 2mm
abutment cuff: 3mm
Overdenture with bar implant space rewuirement?
> 12mm
What is the space rewuirement for hybrid dentures?
> 15mm (10-12)
What is the space requirement for fixed implant?
8-12mm
What is the space requirement for cement retained implant?
8mm
What are the indications for tooth replacement?
Form
Function
Occlusal stability
Esthetics
Phonetics
What are diagnostic casts used for?
dx and tx planning, dx wax up, reduction and provision matrix fabrication, visualization of the anatmy and restorations, dx preparations, analysis of space and edentulous areas
What are the requirements of diagnostic cast mounting?
- accurate casts
- semi adjustable articulator
- facebow
- interocclusal records
- program the articulator- condyler inclination at 30 and bennet at 15
What does chemical erosion look like?
occlusal cupping, roun margins, lesions dont match ofpposing, islands of restorations, unstained and sensitive.
If you see a lot of wear on the L of the maxillary what are you thinking?
chronic regurgitation
what does occlusal wear look like?
wear facets, increased wear in the ant, restorations and teeth wear the same, think parafunction?
What is accuracy?
trueness(most like reality) +precision (consistently of results)
What does a brush/paste misuse look like?
sand blasted, wear on Canine and premolars
What is more accurate VPS or omnican?
very close, but VPS
what is more accurate for implant pick up
digital scan
What are the 7 purposes of diagnostic mounting?
- simulation of mandibular movement
- Analysis of occlusal plane
- Analysis of OCCLSUION and DISCLUSION
- Visualization of anatomy and restorations
- Diagnostic preparations
- Analysis of restorative SPACE
- Analysis of EDENTULOUS AREAS
What are the 5 diagnostic mounting requirements?
- Accurate casts
- SEMI-Adjustable articulator
- Facebow transfer record
- CR interocclusal records-bite reg
- Program articulator via condylar inclination and bennett angle
Alginate setting time is best controlled with?
water temp
What increases as the alginate sets (more time)?
tear strength and resistance to deformation
What is the best way to ensure full set of alginate?
use a timer
How much time does alginate require to set?
2-3 mon after initial set (loss oc tackiness)
What happens to alginate when it is removed from undercuts?
it is compressed
What will help decrease deformation with alginate?
less compression (less undercuts)
less time compressed
What is reasonable bulk for alginate?
5-7mm between tray and teeth
Should you increase or decrease the rate of removal to decrease tearing potential of alginate?
increase rate of removal “snap” removal
How does changing the water:power ratio affect strength??
Increase Water:power = DECREASE of strength
On gypsum casts what and why do they get degraded when sitting in alginate?
via syneresis, and with blood, saliva, water(dilutes stone)
What does it look like when stone is diluted by free water in an impression
soft and chaulky
What is it called when alginate absorbs water?
imbibition
What is it called when alginate shrinks due to loosing water?
syneresis- gel filaments contract and squeeze water out
How soon should you pour alginate?
ASAP. within 12 min
If you cant pour immedately, how should you store it?
in 100% humidity (plastic bag)
Should you ever wrap the alginate in towels or immerse it?
no
What is Celenza Class 1?
a simple holding device- such as hinge
What is celenza class II?
some vertical and horizonal movement - Galetti
although this is capable of excursives, it does not mimic condylar movement
Non-arcon
What is Celenza Class 3A?
Semi adjustable that can only accept protrusive records? HANAU
ARCON or Non-
What is Celenza Class 3B
semi adjustable- can accept lateral and protrusive records (ie Wipmix)
ARCON or Non-
What is Celenza Class 4a
highly adjustable/full adjustable- ARCON
Programmed with engravings
ie: TMJ articulator
Wha is Celenza Class 4b
highly adjustable/full adjustable- ARCON
Programmed with customized condylar paths usually pantograph
ie: stuart, Denar D5A
What is a facebow used to do (2)?
- records the spatial relationship of the max arch to 3 anatomic reference points
- Transfer this relationship to an articulator
What does the facebow record do for mounting?
positioned the maxillary cast in relation to the opening and closing axis of the mandible.
What are the traditional anatomic references for a facebow? What is it for Whip mix? Hanau?
- transverse horizonal axis and one other selected point
Whipmix: Nasion
Hanau: infraorbital rim
How accurate is the Whipmix earbow?
75% of the population is within 6mm of the true hinge axis
If using a Whipmix facebow- what do you set the condylar inclination at?
30 or FB
In centric relation what is the condyle position?
braced in a superior and anterior position.
Restricted to purely rotary movement about he transverse horizontal axis
Why do we use centric relation?
- repeatable
- stability of occlusion
- comfortable
- avoid eccentric interferences
- decrease trauma from occlusion
- Class 3 lever
- interruption of destructive forces on the joint
What kind of lever is the jaw?
Class III
When should you consider using CR?
if multiple (3+) postioer teeth are being restored, or there is evidence of occlusal pathology
What are 3 CR techniques?
- Chin point guidance
- bimanual manipulation- Dr. Dawson
- Lucia Jig - separating the posterior teeth so that the pterygoid muscle releases, allowing the condyles to be seated in the optimal position
- leaf gauge
What could you use for programing the articulator?
lateral or protrusive records (protrusive is more shallow, and “safer” bc ant wall of fossa is shallower than medial wall of the orbiting condyle)
can also match up wear facets
If the inclination on an articulator is steeper, how will that effect cusp creation?
cusps can be steeper if inclination is steeper
What is the static relationship between the incising or masticating surfaces of the maxillary or mandibular teeth ot teeth analogues?
occlusion
What is the static and dynamic contact relationship between the occlusal surfaces of the MAX or MAND teeth during function?
Articulation
What is centric occlusion?
the occlusion when the jaw is in CR
Which cusps are the stamp cusps?
max L
Mand B
Which cusps are the sheering cusps?
Max B
Mand L
What are the advantages of cups to fossa occlusion?
- forces in line with the long axis of teeth
- eliminates the “plunger cusp” effect
- Greater stability of the dental arch
- less tendency towards tooth mobility
What kind of contacts allow for cusp/fossa occlusion?
tripodal- each cusp contacts 3 point on the opposing tooth
What are the contacts in tripodal contact?
B/L Stability: (A, B, C)
M/D stability: closer stoppers and equalizers
What are the A contacts? in Bucco -lingual stability
Shearing cusps of the maxillary teeth occlude with the stamp cusps of the mandibular teeth (B cusps)
What are the B contacts in B/L stability?
Stamp cusps of the max teeth occlude with Stamp cusps of Mand teeth
What are the C contacts in B/L stability?
stamp cosps of max with shearing cupss of mand (L cusps)
Is it stable? A+B contacts
Stability
Is it stable? C+B contacts
Stability
Is it stable? A+B+C contacts
Stability
Is it stable? A+C contacts
max teeth move buccally, mand move L
Is it stable? B contacts only
Max teeth move L, Mand teeth move B
What is the purpose of closure stoppers?
stops the closure of the mandible.
neutralizes forces exerted by equalizers
What is arcon vs non-arcon
Arcon- condylar element on on lower part
non-arcon- condylar element is max
What articulator do you use?
Whipmix 4000
semi-adjustable
Arcon
Celenza Class 3b
What is condylar inclination and what the the standard setting?
angle ofthe condyle translation down the articular eminence, which is either steep or shallow
steep= teeth come back together quickly
shallow- teeth are slower to disclose
Standard is 30 degrees
What is the bennett angle and what is the standard setting?
Progressive side shit
standard is 10-15
How do you take a record for the bennet angle?
Obtaining a lateral record is accomplished by having the patient move their jaw to the left and right. At the end of each movement the clinician will use registration material to capture the position which will register the patients Bennett Angle/Lateral Condylar Guidance. This record will be placed between the mounted maxillary and mandibular casts independently to program the lateral setting on the articulator
What to do if you have a pier abutment?
consider implant or use of a semi-precision (looser) attachment
Male portion= PATRIX= Tennon–> on the MESIAL aspect of the distal Pontic
female portion=MARTRIX=mortise–> on the DISTAL access of the retainer on the pier abutment which acts as a for breaker
What is Y-ZTP and what are the benefits/advantages?
Yttria-stabilized tetragonal zirconia polycrstal
yittrium oxide is added to zirconia to stabilze the structure and prevent cracking allowing for more tetra phase.
transition from tera to monoclinic creates a 3-5% increase of volume- sleaing the crack.
white color, great physical properties, transformation toughening, cad/cam capable, more accurate milling due to 25% decrease in size post sintering,
disadvantages: opaque, more sintering, questionable bonding, wears if not polished
What causes B/L and M/D stability?
BL: ABC
M/D equalizers and closure stoppers
What are the different types of ceramics?
Feldspathic,
Lithium Disilicate
Zirconia
Resin infused ceramics (like enamic)
conventional
CAD/CAM
Identify the impression coping…. L=, and R=?
Nobel Biocare external hex
L= open tray pick up
R= closed tray pick up
Difference between closed and open tray?
open = hole cut in ray to unscrew impression copings before removal. Used for multiple implant impressions and eliminates the need to reinsert the impression coping manually after the impression is removed
Flexing of the mandible and implant placement- are we concerned about it and why? Where are most forces placed
why? damage to the implant, loosening of the parts
most forces are at the crest of the bone
Describe MIP. CO, CR
MIP: where all the teeth fit together. Maximum intercuspation postion
CO: centric occlusion- occlusion that = CR when the teeth just contact.
CR: most anterior and superior position of the condyle in the fossa(against the slope of the articular eminence) where the disc is thinnest and avascular- max/mand relationship.
What is the restorative space for implants for screw retained
6-7mm
How to you pre-treat feldspathic for seating?
5.5% HF x 60 secs
silane, MPS primer, Monobond plus
How do you pre-treat lithium disilicate before seating?
5.5% HF x 20 secs, then silane, MPS primer, Monobond plus
What is mutually protected articulation?
The posterior teeth protect the anterior teeth in MIP and the ant teeth protect the post teeth in excursive
what are the characteristics of MIP?
MIP occurs with condyles in centric relation (no slip from CO to MIP) post teeth hold shim, while Ant teeth drag shim
immediate separation of post teeth in any eccentric movement
Ant guidance- ant teeth provide separation of post teeth in eccentric movements.
What is group function?
unilateral shared guidence with ant and post.
forces shared among the teeth
no no-working interferences in eccentric movements
What is balanced articulation?
Simultaneous cross arch contacts in MIP and eccentric movements- indicated for dentures
What are the primary determinants of retention?
total occlusal convergence: taper 10-22°
-prep height:
Anteriors- 3.0mm
Posteriors - 4.0mm
-Prep height/width ratio: >0.4
What is the ideal and minimum Crown:root ratio
ideal: 2:3
minimum: 1:1
What re the requirements for a provisional restoration?
pulpal protection
positional stability
occlusal function
cleansability
non-impinging margins
strength and retention
esthetics
What are the goals of gingival retraction?
vertical access for impression materials
horizontal volume for impression material
crevicular fluid control
maintain and protect the periodontium
facilitate axial contour
What are ways you can expose the finish line for your crown prep?
Retractions: copings, bands, cord, pastes,
Curettage
rotary, electrosurgical, laser
