Operative, 11/1/11

Front 1

Advantages for indirect?

Back 1

Advantages: more durable
-material is better - durability, color and anatomical stability
-unlimited control: technique, visiblity
-some things must be indirect

Front 2

Disadvantages for indirect?

Back 2

-hard to be minimally invasive (in direct you can be minimally invasive)
-more time/ less convenience
-many interdependent steps: each step determines the others.
-lab tech/lab fee
-cement is a weak link! cement should occupy only a tiny part of the restoration.

Front 3

Intracoronal vs. extracoronal

Back 3

Extracoronal: uses external walls for resistance and retention. Crown is classic example.

Intracoronal: internal walls diverge slightly that provide most of resistance and retention. Like inlays.

Front 4

Protective vs. non protective

Back 4

Protective: must protect cusps or else they are susceptible to bending under function. the wider the inaly, the more flexion you'll get. Any prep that shoes all the cusps is called protective. No cuspal breakage under function.
Crown is extracoronal + protective

Non protective: leaves cusp tips exposed, and susceptible to bending and flexing. 2 surface inlay.

Front 5

Inlay

Back 5

Indirect restoration made outide the mouth and inserted into the mouth, and does not cover any cusps. 1, 2, 3 surface inlay. Class 5 inlay.

Front 6

Onlay

Back 6

restoration that is indirect that covers all of the cusps of a posterior tooth. Protective also.

Front 7

Inlay-onlay

Back 7

Only some of the cusps are covered. Another type of indirect restoration.

Front 8

Partial covereage and full crowns

Back 8

Partial coverage: one of the 4 axial walls is left unprepared or unrestored. The facial wall is usually not prepared for partial crown. Very good alternative to full crowns.

Front 9

Material choices

Back 9

-will be new materials for inlays and onlays.
-cast gold alloys (type 2, 3, or 4): old fashioned. still the gold standard. type 3 has enough gold. More gold is has the softer it is. type 2 is occasionally used for inlays since you can still burnish the margins.
-feldspathic porcelain (a glass ceramic): around for a long time. old fashioned porcelain but because of the properties, is not great in terms of fit. in oven it shrinks (even more so than composite). not as strong either.
-Leucite resinforced glass ceramic (IPS Empress) - first significant improvement over porcelain. fit better + broke less.
-lithium dislicate (e-max): 4X stronger than empress. easier to make, cheaper. nice esthetic result too. hottest one.
-Processed composite resin - bake in oven. Concept brand - super polymerized composite. internal surface has to be treated to make sure they etch properly.

Front 10

Fabrication choices

Back 10

-decide on how material is made.
-lost wax cast metal: good in terms of small amt of space that exists between restoration + tooth. good seating. centuries old.
-lost wax pressed ceramic: not melting gold but ceramic material.
molten glass is pushed by piston into the cast.
-fired feldspathic porcelain
-lab milled ceramic: trendy. block of material placed in cad/cam. diamond burrs grind in the block.
doesn't rely on personnel. less expensively.

Front 11

Cementation "choices"

Back 11

-conventional
-adhesive: must be placed this way, some are placed in either case.

Front 12

General preparation principles

Back 12

-path of insertion/withdrawal
-retention (height + taper)- need alittle bit so it doesn't fall off.
-depth (thickness) - all indirect have thickness requirement (at least 1 mm).
-resistance form - occluding surface of crown prep is flat.
-internal angles?? for metallic theoretically sharp intneral line angle is okay but sharp line angles for ceramics is not allowed. also for pfm
-cavo surface: every specific material has own set of requirements.
-outline form

Front 13

Path of insertion/path of withdrawal

Back 13

-for inlay: vertical slide in and out. should be perpendicular to plane of occlusion. should be parallel to long axis of tooth. if tooth is tipped, its more important that its perpendicular to occlusion.

Front 14

What's an "undercut"?

Back 14

Something is in the way of a smooth path of insertion.
1. Line up path of vision between one eye and tooth's path of insertion (directly above the tooth, perpendciular to plane of occlusion)
2. Are you lined up properly? Can you see all of the margins, and can you see the axial wall?
3. If there's an undercut..
a. remove tooth structure occlusal to the undercut.
b. blocking it out by filling it with a direct material (flowable composite). best done with a dentin undercut.