Fixed Prosth Midterm Study Guide

replacement, restoration

Fixed Prosthodontics is the branch of Prosthodontics concerned with the _________ and/or _______ of teeth by artificial substitutes that cannot be removed by the patient

Abutment

In a fixed partial denture, the retainer is on the __________ tooth

Replacement

In a fixed partial denture, the pontic is on the __________ tooth

Need for endodontic tx (3%)

(Porcelain Veneer Fracture: 3%; Loss of Retention: 2%)

What is the most common complication for single crowns?

Caries on abutment (18%)

(Need for Endodontic Tx: 11%; Loss of Retention: 7%)

What is the most common complication for FPD?

Debonding (23%)

(Tooth Discoloration: 18%; Caries: 7%)

What is the most common complication for Resin Bonded FPD?

1. Diagnosis + tx plan(s)

2. Actual treatment:

- Preparatory phase

- Operating phase

3. Post-operative, Maintenance and Recare

What is the order of treatment for single crowns?

- Serve as a complement tool in addition to clinical examination

- Provide a legal proof of pt’s current occlusion

- Allow clinician to modify occlusal pre-tx plan prior to establish a definitive Tx Plan

- Allow clinician to evaluate pt’s occlusion in centric + eccentric positions

- Allow clinician to determine inter arch distance, relationship between the teeth and alveolar ridge and allow clinician to make as many alteration to as clinician’s desire w/ absence of the patient

What is the purpose of mounting diagnostic casts on an articulator?

Irreversible hydrocolloid

The alginate hydrocolloid we use in lab is also know as __________

An irreversible hydrocolloid impression material used to make a negative reproduction of oral tissues for diagnostic casts

- Salt of alginic acid (Na or Ca alginate)

- Alingates are cell wall constituents of brown algae

- Most widely used impression material in dentistry

What is alginate?

1. Inexpensive

2. Easy manipulation

3. Pleasant taste

4. Able to displace blood and body fluids

5. Hydrophilic

6. Easily poured

7. Can be used with stock trays

8. Accurate if handled properly (for diagnostic casts)

8 advantages of alginate hydrocolloids

1. Low tear resistance

2. Must be poured immediately

3. Limited detail reproduction

4. Dimensionally unstable (syneresis vs imbibition)

5. Can only be used for single casts

6. Incompatible w/ epoxy resin die materials

6 disadvantages of alginate hydrocolloids

1 minute

How long should you mix for regular setting alginate?

45 seconds

How long should you mix for fast-set setting alginate?

3.5 minutes

What is the set time for alginate after mixing?

Lower

(alginate) Lower or Higher W/P ratio?

- Increase in strength

Lower

(alginate) Lower or Higher W/P ratio?

- Increase in tear strength

Lower

(alginate) Lower or Higher W/P ratio?

- "Better" consistency

Lower

(alginate) Lower or Higher W/P ratio?

- Decrease in working time

Lower

(alginate) Lower or Higher W/P ratio?

- Decrease in setting time

Lower

(alginate) Lower or Higher W/P ratio?

- Decreased flexibility

Higher

(alginate) Lower or Higher W/P ratio?

- Decrease in strength

Higher

(alginate) Lower or Higher W/P ratio?

- Decrease in tear strength

Higher

(alginate) Lower or Higher W/P ratio?

- Runny consistency

Higher

(alginate) Lower or Higher W/P ratio?

- Increase in working time

Higher

(alginate) Lower or Higher W/P ratio?

- Increase in setting time

Higher

(alginate) Lower or Higher W/P ratio?

- Increased flexibility

Increase

Cold water will ________ the working and setting times

Insufficient

_________ mixing results in a grainy mix and poor recording of details

100%, 30 minutes

Storage of impressions in either air (syneresis) or water (imbibition) results in significant dimensional change. If needed, impression materials should be stored in _____% humidity for _______ minutes prior to pouring

- Sodium hypochlorite

- Iodophors

Disinfectent of alginate hydrocolloids can be accomplished by immersion in ___________ or ___________

Syneresis

Define the following:

Loss of water due to dehydration that causes shrinkage

Imbibition

Define the following:

Tendency to absorb water that results in swelling

- Not centered with midline

- Voids

- Missing anatomy

What don't you like about this impression?

- Waited too long to pour stone

- Pour mixing spatulation

What do you think happen to this cast?

Type 1, white impression plaster

This is a dental gypsum specification of which type of stone?

- Setting expansion: 0-0.15%

- Compressive strength: 580-1160 psi

Type 2, white mounting plaster of paris

This is a dental gypsum specification of which type of stone? - Setting expansion: 0-0.30%

- Compressive strength: 1300 psi (minimum)

Type 3, yellow stone study cast

This is a dental gypsum specification of which type of stone?

- Setting expansion: 0-0.20%

- Compressive strength: 2900 psi (minimum)

Type 4, working cast for c&b

This is a dental gypsum specification of which type of stone?

- Setting expansion: 0-0.15%

- Compressive strength: 5100 psi (minimum)

Type 5, green working cast (Die Keen)

This is a dental gypsum specification of which type of stone?

- Setting expansion: 0.16-0.30%

- Compressive strength: 5100 psi (minimum)

Type 3

(allows expansion and acrylic shrinks)

What type of stone do you use when you are going to make an acrylic RPD?

Type 4

(does not expand - could be 5 but Dr. Nui said most likely 4)

What type of stone do you use when you are going to make a crown or bridge?

Type 3

What type of stone was this from?

Type 5

What type of stone was this from?

Yes

(Maxillary acrylic CD)

Did the student use proper type of dental stone to form this working cast for the dental prostheses?

Yes

(Mandibular metal base RPD)

Did the student use proper type of dental stone to form this working cast for the dental prostheses?

No - should use type 3

Treatment plan is for a mandibular Resin Base RPD. Did the student use proper type of dental stone to form this working cast for the dental prostheses?

No - should use type 3

Treatment plan is for Immediate Max CD/Mand Resin Base RPD. Did the student use proper type of dental stone to form this working cast for the dental prostheses?

Type 3

What type of dental stone allows expansion to compensate for acrylic shrinkage?

Type 4 or 5

What type of dental stone provides limited expansion—good for prosthese that require high precision such as crown and bridge or Fixed Dental prostheses including dental implant restorations, and metal base RPD Framework?

A gypsum product made from calcined calcium sulfate hemihydrate, used to create positive casts from impressions

What is dental stone?

Exothermic

The setting reaction of the hemihydrate (gypsum) is the reverse of the first stage of dehydration and is ___________

Density of powder

Why do plaster, stone, and high-strength stone have differences in water requirement?

47 ml per 100 g powder

What is the water/powder ratio of laboratory plaster (type 2)?

30 ml per 100 g powder

What is the water/powder ratio of dental stone (type 3)?

26 ml per 100 g powder

What is the water/powder ratio of mounting stone (type 3)?

28 ml per 100 g powder

What is the water/powder ratio of microstone (type 3)?

21 ml per 100 g powder

What is the water/powder ratio of Die-Keen (type 4)?

Increase

An __________ in temperature of gypsum will decrease setting time

Low

_________ water/powder ratio of gypsum harden more quickly, and will produce less microporosities related to residual unreacted water. It will, however, increase microporosity related to crystal growth

Faster

The more you spatulate/faster you spatulate gypsum, the _________ the setting time

Hand

Setting time increases when mixed by hand or by vacuum mix for gypsum?

Vacuum

Is compressive strength higher when mixed by hand or by vacuum mix for gypsum?

Hand

Is there a greater expansion % at 2 hours when mixed by hand or vacuum mix for gypsum?

Hand

Is viscosity increased when mixed by hand or vacuum for gypsum?

Inversely

Setting expansion is _________ proportional to the water-powder ratio for gypsum

true

t/f: air moisture contamination can affect the setting time and expansion of gypsum

K2SO4 or Sodium Citate

Setting expansion of gypsum can be controlled with the use of additives in the powder, such as what?

inversely

strength of gypsum is _________ proportional to the water/powder ratio

increases

using a low water/powder ratio of gypsum for maximum strength also _________ setting expansion

doubles

Removal of uncombined water from cast gypsum by low-temperature drying approximately _________ the strength

True

T/F: Drying of gypsum should be carefully controlled, otherwise shrinkage and reduction of strength can occur

Saturated solution of calcium sulfate

Long-term immersion of gypsum in water is contraindicated; if needed, what can you use instead?

Increase

(gypsum) Increase in water/powder ratio will ______ setting time

Decrease

(this originally said increase but I believe he said it should be DECREASE)

(gypsum) Increase in water/powder ratio will ______ consistency

Decrease

(gypsum) Increase in water/powder ratio will ______ setting expansion

Decrease

(gypsum) Increase in water/powder ratio will ______ compressive strength

Decrease

(gypsum) increase rate of spatulation will ______ setting time

Decrease

(gypsum) increase rate of spatulation will ______ consistency

Increase

(gypsum) increase rate of spatulation will ______ setting expansion

Not effect

(gypsum) increase rate of spatulation will ______ compressive strength

Decrease

(gypsum) increase water temperature of mixing water will ______ setting time

Decrease

(gypsum) increase water temperature of mixing water will ______ consistency

Increase

(gypsum) increase water temperature of mixing water will ______ setting expansion

Not effect

(gypsum) increase water temperature of mixing water will ______ compressive strength

- Capture all vital anatomic landmarks necessary for tx plan

- No nodules or blebs

- No voids

- Good surface characters

- Be able to articulate and both arches should have same occlusion as typodont (or simulated patient's occlusion)

How should you assess your casts?

True

T/F: DO NOT DROP MIXED ALGINATE or MIXED DENTAL STONE FALL INTO THE SINK DRAIN

Maximum Intercuspal Position (MIP)

Which occlusal relationship?

The complete intercuspation of the opposing teeth independent of condylar position, referred to as the best fit of the teeth regardless of the condylar position

- Can be used when at least 3 non-aligned pairs of teeth occluding

Centric relation (CR)

Which occlusal relationship?

A maxillo-mandibular relationship (MMR) in which the condyles articulate w/ the thinnest avascular portion of their respective disks with the complex in the anterior-superior position against the posterior slopes of the articular eminencies

Centric relation (CR)

Which occlusal relationship?

- Unstrained, physiologic position

- Repeatable. the mandible is restricted to a pure rotary movement

- A ligament position

- Independent of tooth contact

MIP

MIP or CR?

- Dependent of tooth contact

MIP

MIP or CR?

- Independent of condylar position

MIP

MIP or CR?

- "Simple"

CR

MIP or CR?

- Independent of tooth contact

CR

MIP or CR?

- Reproducible

CR

MIP or CR?

- Provides anatomic / physiologic stability

Articulation

Define the following:

The static and dynamic contact relationship between the occlusal surfaces of the teeth during function

Sagittal

This is a trajectory of how the mandible moves in what plane?

Horizontal

This is a trajectory of how the mandible moves in what plane?

Frontal

This is a trajectory of how the mandible moves in what plane?