3. full coverage restorations - tooth preps

what happens in the 1st, 2nd, and 3rd visits in clinic vs in lab?

amalgam and composite restorations

direct

intracoronal and extracoronal

indirect

inlay and onlay

indirect intracoronal

gold and ceramic

indirect intracoronal onlay

full coverage and partial coverage

indirect extracoronal

• full cast metal crown

• metal ceramic or PFM

• all ceramic

indirect extracoronal full coverage

• cast metal ¾ crown

• veneer

• resin bonded restoration

indirect extracoronal partial coverage

what are the four types of crowns discussed?

• full cast metal

• PFM

• all ceramic

• partial coverage (3/4, 7/8)

why do we prep teeth for fixed prosth?

we reduce to make space to replace what is missing

advantages of which full coverage restoration?

full cast metal crown

advantages of which full coverage restoration?

PFM crown

advantages of which full coverage restoration?

all ceramic crown

disadvantages of which full coverage restoration?

full cast metal crown

disadvantages of which full coverage restoration?

PFM

disadvantages of which full coverage restoration?

all ceramic

what are some things to keep in mind with indications of different full coverage restorations?

• Conservativeness

• Strength

• Esthetics

• Occlusion

• Tooth structure

• Tooth condition

• Age

indications of which full coverage restoration?

full cast metal

indications of which full coverage restoration?

PFM

indications of which full coverage restoration?

all ceramic

contraindications of which full coverage restoration?

full cast metal

contraindications of which full coverage restoration?

PFM

contraindications of which full coverage restoration?

all ceramic

what are the three major principles of tooth prep?

biological, mechanical, esthetic

what are the three factors of the biological principles of tooth prep?

• preservation of tooth structure: temp, chemical, bacterial

• preservation of periodontium

• marginal integrity

what are the three factors of the mechanical principles of tooth prep?

• retention: path of insertion, undercut

• resistance

• structural durability

taper, occlusal inclines, and margin geometry which biological factor of tooth prep?

preservation of tooth structure

margin placement which biological factor of tooth prep?

preservation of periodontium

margin design which biological factor of tooth prep?

marginal integrity

geometry of tooth prep and therefore taper and surface area align with which mechanical factor of tooth prep?

retention

taper, width, height where h/w = 0.4 and at least 3mm AND groove and box align with which mechanical factor of tooth prep?

resistance

functional bevel and second plane reduction align with which mechanical factor of tooth prep?

structural durability

bio - preservation of the periodontium

what are the three options for margin placement?

• Supragingival: above gingival margin

• Equigingival: at gingival margin

• Subgingival: 0.5 mm below

which marginal placement is indicated for caries?

subgingival

bio - marginal integrity

shape of margin is determined by (?)

bur shape

which margin designs and related bur shape?

mechanical - retention and resistance

convergence of two opposing external walls of crown prep as viewed in a given plane (path of insertion), e.g. MD BL

taper

mechanical - retention and resistance

• any irregularity on the wall of a prepared tooth that prevents the withdrawal or seating of a crown or wax pattern

• when the divergence exists between the opposing axial wall or wall segment

undercut

what is the ideal taper and what is clinically acceptable?

• ideal: 6-10°

• clin acceptable: 10-20°

• round end of tapered diamond bur us 2-3° so 4-6 total

increasing taper (increases/decreases) retention and resistance

decreases

taper on which third of crown is most important?

cervical

• imaginary line along which the restoration is placed onto or removed from the prep

• the specific direction in which a prosthesis is placed on the residual alveolar ridge, abutment teeth, dental implant abutment(s), or attachments

path of insertion

describe how to check taper/undercut

what is the height : width ratio for geometry of tooth prep? (mechanical - resistance)

4:10 +

for lingual of anterior teeth and premolar axial wall height should be

3mm at taper <10°

for molars axial wall height should be

3.5-4mm

geometry of tooth prep

geometry of tooth prep

what is the most acceptable but not the only procedure flow for tooth prep?

1. Occlusal reduction

2. Buccal and lingual axial reduction

3. Proximal axial reduction

4. Finishing

5. Evaluation

start reducing slowly!

armamentarium for tooth prep

for our tooth prep where are we marking CEJ and where is the finish line?

for our tooth prep where are we positioned?

diameters of our burs