Fixed Pros Lecture 25

Front 1

What is the Three Key Features of Ideal tooth preparation?

Back 1

-Provide sufficient "dimension of restorative material" for strength and esthetics
-Provide sufficient "remaining tooth structure" to maintain integrity of tooth (prevent dentin fracture)
-Provide "adequate R&R form to help maintain the crown in the oral cavity

Front 2

What is Retention form?

Back 2

-Features of tooth prep that prevent removal of the prosthesis along it's path of insertion (long axis of the preparation)

Front 3

What is resistance form?

Back 3

-Those features of tooth preparation that prevent dislodgement of the prosthesis from forces directed apically or obliquely against the prothesis (lateral forces of occlusion)

Front 4

What are biomechanical features of Retention Form?

Back 4

-Prep. taper (convergence)
-Length of prepared axial walls
-Surface roughness of preparation
-Surface area of preparation
-Mechanical properties of cement
-Casting/tooth prep for cementation
-Retention grooves/boxes

Front 5

Biomechanical features of Resistance form?

Back 5

-Preparation taper (convergence)
-Length of prepared axial walls
-Retention grooves/boxes
-Occlusal/incial tooth contours

Front 6

Crowns with short axial walls might require more axial parallelism (less TOC) than those with long axial walls (T/F)

Back 6

True

Front 7

Methods to Improve R&R?

Back 7

-Paralleling devices
-Crown extension surgery
-Rapid orthodontic extrusion
-Modification of existing tooth preparation by repreparation or placement various core foundation materials (endo/dowel/core,pin, amalgam., pin composite)
-Cementation factors

Front 8

Modificaiton of Existing Preparation?

Back 8

-Conversion of chamfer to shoulder (increases parallelism)
-Mesial/distal grooves/boxes (resists F-L displacements)
-Facial/Lingual grooves/boxes (resists M-D displacement)
-Occlusal morphology
-Placement of core foundation material

Front 9

Functional occlusion (lateral or protrusive functional movements) can dislodge a crown either:

Back 9

-Lingually for mandibular crown, or
-Facially for maxillary crown

Front 10

If the rotational arc, ____ ____ ____ ____ _____ _____, you have adequate resistance form.

Back 10

If rotational arc, from facial to lingual margin, passes through tooth structure, you have adequate resistance form.

Front 11

Over-tapered crown in M-D dimension is held in place (somewhat) by what?

Back 11

-Adjacent proximal contacts
-Should modify prep form chamfer to shoulder to have more parallel

Front 12

To maximize R&R form on anterior teeth, ____?

Back 12

-Place M-D resistance grooves

Front 13

What is the purpose of The patrix?

Back 13

-Molar is too severe mesial tipping. So you need to use a connector (Ney mini-rest, w/ patrix upside down)

Front 14

What are the cementation factors?

Back 14

-Cement selection (adhesive cements for situation with poor R7R form)
-Dentin preparation to enhance adhesion (surface roughness "diamond")

Front 15

What are the characteristics of cement selection?

Back 15

-Strength (shear, tensile, compressive)
-Solubility
-Film thickness (ADA=<25 microns)
-Adhesion to tooth structure

Front 16

How do you prep. dentin to enhance cement adhesion?

Back 16

-Diamond vs. carbide prep
-Cleaning dentin surface
-Etching/drying protocol
-Use of dentin bonding agents

Front 17

Prosthesis prep to enhance coment retention?

Back 17

-Microabrasion
-Silicoating or tin plating
-Adhesive cement selection
-Complete removal of "fit checkers"

Front 18

Often, F and L resistance grooves are indicated, especially when?

Back 18

-Especially on distal extension RPD survery crowns