Prosth 3 Final

Why do restorations need to be layered?

Achieve optimum esthetics

Complications of dental whitening

Cervical root resorption

Enamel/Dentin damage

inhibition of adhesive bonding

Gingival irritation

How do you improve shade of a tooth?

External bleaching

Internal Bleaching

Prosthodontic options

Chamfer margins on the lingual surface of lower teeth is usually attributed to?

Erosion

Prep dimensions occlusal/margin for 3Y, 4Y and 5Y zirconia

3Y- 1.0 mm occlusal, 0.6mm margin

4Y- 1.2mm occlusal, 0.8mm margin

5&- 1.5mm occlusal, 1.0mm margin

What is the dental surveyor used for during tx planning

Evaluate undercuts and their influence

Evaluate relative alignment of the long axis of teeth

Determine POI and interference

Sequence of fabricating retainer for RPD

Survey diagnostic cast

Retainers and Design RPD

Tooth Mod and verification (Guide planes, HOC, Rests)

Fabrication of surveyed crown (Prep, impression, bite reg, wax-up, casting)

Re-survey retainer and cementation

RPD impression

Prior to final impression for surveyed crown you need to:

make tooth modifications on other abutment teeth first and mods on all other teeth not receiving a crown first.

A minimum metal thickness of __ mm between rest seat and occlusal aspect of prepared tooth is advisable

1

What is important for tooth preparation for tilted tooth

Reduce side needing greatest reduction first, reduce other side only as much as necessary to achieve ideal taper

Framework design for metal-ceramic crown considerations (2)

Adequate thickness of metal (1mm) must remain between lateral walls of occlusal rest seat and junction

Occlusal rest seat should not be placed directly on porcelain (1mm from junction)

What is the purpose of the special finishing procedures of the milling process

Smooth even surface that is parallel to established POI

How much interocclusal space is required at mesial marginal ridge

2mm

What is highest priority for modifications on existing cast-metal restorations and the risk associated?

Sufficient space when preparing rest seats.

Perforation of the casting and exposing underlying tooth structure

What is the direct-Indirect technique when fabricating a crown under and existing RPD

a pattern is fabricated from an autopolymerizing acrylic resin and wax which contacts internal aspect of RPD and placed on a die which is waxed and then casted.

What is the disadvantage of indirect technique when fabricating a crown under an RPD

The partial RPD is required in the lab throughout crown fabrication

Advantages and disadvantages of attachment for RPD

Adv: Less liable to fracture, less bulky, better retention/stability, less food trap than clasps

Disadv: Complex design, fabrication and clinical tx, many are contraindicated for short abutments, components wear over time and need repair.

Min height of abutment for attachments for RPD

4-6 mm

Extracoronal attachment and considerations

Male (key on RPD) + female (keyway on abutment) components are positioned outside contour of abutment tooth.

Esthetic but place unfavorable stresses on abutment teeth + hygiene concern.

Prefabricated attachments and considerations

Precision milled male-female assembly

Retention from friction

Can be moved in only single direction

Eliminate unesthetic facial clasp

Lab made attachments and considerations

Referred to as dovetails, have limited amount of frictional retention

Majority are tapered for ease of fabrication

at least 1mm from MC junction

What 3 factors contribute to exposure

Shutter speed, aperture (opening) and ISO (light sensitivity)

3 benefits of low profile stud attachments

Additional support + retention for RPDs

Alleviate stress with remaining teeth in distal extension situations

Help guard periodontally or compromised teeth

A bar radiucular attachment should be placed ___mm from the tissue

2 mm

Key cause of attrition?

Tooth grinding

Factors contributing to abrasion

abrasives, stiff toothbrushes, vigorous tooth brushing

Extrinsic and intrinsic factors of erosion

Extrinsic - citrus, wine, soda

Intrinsic - GERD, vomiting, bulimia

The art of reproducing natural defects on restorations with stains or surface texture to make them blend in and achieve a natural appearance

Characterization

What is preferential for tooth display at rest and gingival display at smile?

TDAR : 3mm

GDAS : -2mm

How to calculate freeway space

VDR - 3mm

T/F There are plenty of studies to show effectively how true transverse horizontal axis is calculated in the software program.

False, unknown and need studies to assess accuracy

What is the most important factor in determining how much tooth reduction is needed for mechanics + esthetics?

path of placement

What is important for tooth preparation regarding mandibular molars

lingual inclination requires reducing slightly more in occlusal 2/3s of lingual axis surface to allow development of guide planes

Shade matching distance

25-35 cm or 10-14 in

T/F Keep the tab as dry as possible when comparing to tooth

False, both tab and tooth should be wet

Lamp specifications for proper shade matching

D65/D55 or similar
CRI of 90 or greater
1000-1500 lux

What % of males/females are color deficient

8% of males

0.5 % females

T/F Color deficient people are often referred to as colorblind

False