Full Crown

Full Crow

n Module

Learner Level 1 M

astery of Tooth Preparation

Restoration / Tooth #

Full Gold C

rown (FG

C) / 30

Extensions: P

orcelain Fused to Metal (P

FM) / 12

All C

eramic / 8

Estimated Set U

p Time: 30 m

ins Estim

ated Com

pletion Time: 6 hours

I. Module Inform

ation In level 1 of the Full C

rown M

odule, we are going to apply all the principles of

preparing tooth to receive a full crown restoration. Y

ou will be guided w

ith the step by step procedures in preparing tooth #30 (Fig. 1) that is going to be restored w

ith a Full Gold C

rown (FG

C) (Fig. 2). A

n extension of the exercise is also included for further practice and efficiency.

Fig. 2. Prepared tooth #30 to receive FG

C

restoration Fig. 1. Pre-operative photo of tooth #30

II. Setting up of the Articulated Teeth

Since this is a sim

ulated exercise, tooth preparation should be done on a Frasaco

Model m

ounted on the simulator.

1. G

et a typhodont tooth # 30. 2. Y

ou may also start setting up for your extensions and m

ount teeth # 12 and #8

3. Screw

it on the space provided. 4. M

ake an alginate impression and pour it w

ith the microstone.

5. Mount the articulator in the sim

ulated patient. 6. P

repare silicone putty matrices of the tooth and the adjacent teeth

7. Prepare your instrum

ents (handpiece, burs and mouth m

irrors, etc,) 8. H

ave the evaluation criteria with you.

Full Crow

n Module: Learner Level 1

R

anier M. A

darve, DM

D, M

S, M

HP

E

University of M

innesota School of D

entistry 1

Clinical R

elevance A

s with any fixed prosthodontic procedure, you should alw

ays have a diagnostic cast to visualize your planned procedure. The silicone m

atrix will guide you during preparation as w

ell as help you determ

ine the adequacy of your tooth reduction. Take note that in some instances, silicone

matrix m

ay not be the best technique to use to evaluate your preparation. Other techniques, like

using a vacuum-form

ed matrix m

ay be more practical especially on teeth that are tilted, rotated or

deviated from norm

al position. We w

ill deal with these kinds of situation in the succeeding levels

of the Full Crow

n Module.

III. Preparing Tooth for Full Crow

n Restoration

In the succeeding steps, we w

ill be reducing the tooth structure per tooth surface. A

lthough the sequence of surface to be reduced may vary according to

operators preference, our recomm

ended steps would focus m

ore on the goal(s) of each procedure and the am

ount of tooth structure to be reduced. As you begin

your tooth preparation, read the full crown evaluation m

atrix to guide you in applying the principles of the tooth preparation. Instructors N

ote Full C

rown P

reparation requires the understanding of the fundamental principles. A

s a review,

these are: a.

Conservation of tooth structure

A

void weakening the tooth unnecessarily.

A

void comprom

ising the pulp. b.

Resistance form

Prevent dislodgm

ent of the restoration by apical or obliquely-directed forces. c.

Retention form

Prevent dislodgem

ent of the restoration by forces along the path of insertion, including the long axis of the tooth

d. S

tructural durability.

Provide enough space for the crow

n which is sufficiently thick to prevent

fracture, distortion or perforation. e.

Marginal integrity

P

repare a finish line to accomm

odate robust margin w

ith close adaptation to m

inimize m

icroleakage. f.

Preservation of the periodontium

Shape the preparation such that the crow

n is not over contoured and its m

argin is accessible for optimal oral hygiene.

g. E

sthetic Considerations

C

reate sufficient space for esthetic veneers where indicated

Make sure these principles m

ake sense to you for they will surely guide you in your procedures.

If you need further explanations of these principles, dont hesitate to ask your instructor. Full C

rown M

odule: Learner Level 1

Ranier M

. Adarve, D

MD

, MS

, MH

PE

U

niversity of Minnesota S

chool of Dentistry

2

A. O

cclusal Surface Reduction

A. O


The goal of occlusal reduction is to provide 1.0 mm

uniform reduction of occlusal

The goal of occlusal reduction is to provide

R

anier M. A

darve, DM

D, M

S, M

HP

E

University of M


entistry 3

1.0 mm

uniform reduction of occlusal

surface and following the contour of the tooth. This can be accom

plished with

the help of depth grooves.

1. With your round-end tapered diam

ond bur, place the depth grooves (Fig.3) in the follow

ing areas: a. prim

ary development grooves

b. crest of the trianglular ridges

Fig. 3. O

cclusal Surface Depth G

rooves/ G

uides

2. Orient the bur parallel to the inner inclines.

3. With the sw

eeping movem

ent, proceed to remove occlusal tooth structure

to the predetermined depth by rem

oving the islands of tooth structure betw

een depth grooves. 4. Follow

the up and down contours of the ridge and cusps inclines (Fig. 4).

a. Occlusal m

orphology is never flat. b. A

chieve Occlusal P

lanar Reduction-

-occlusal reduction following the planar contours of the tooth

as they are presented pre-operatively.

Fig. 4. Occlusal Planar R

eduction

Full Crow


R

anier M. A

darve, DM

D, M

S, M

HP

E

University of M


entistry 3

5. Verify the uniform

ity and the amount of occlusal reduction (Fig 5). This

can be done either by: 5. V

erify the uniformity and the am

ount of occlusal reduction (Fig 5). This can be done either by:

a. The silicone putty matrix


b. Articulating the m

axillary and the mandibular arch

b. Articulating the m

axillary and the mandibular arch

c. A

softened piece of wax

c. A

softened piece of wax

Fig. 5. O


Clinical R

elevance The am

ount of tooth structure removal including the am

ount of occlusal reduction depends on the type of restoration. For FG

C, 1.0 m

m reduction should be adequate to provide adequate space

for the metal thickness w

ithout interfering with occlusion. H

owever, in actual clinical cases, the

clearance may vary and m

ay require more tooth structure rem

oval. You can use any of the

suggested techniques to verify the adequacy of your reduction. B

. Buccal and Lingual Surfaces R

eductions The goals of B

uccal and Lingual reductions are to remove adequate am

ount of teeth structures to (1) rem

ove the natural undercut contour of the tooth and (2) achieve 6 degrees total occlusal convergence.

6. With your round-end tapered diam

ond bur, place the depth grooves in the follow

ing areas of the Buccal surface and extend apically upto 1.0 m

m to

the margin of the gingiva (Fig. 6).

a. development groove(s)

b. line angle(s)

Fig. 6. Buccal Surface D

epth Grooves /

Guides

Full Crow


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anier M. A

darve, DM

D, M

S, M

HP

E

University of M


entistry 4

R

anier M. A

darve, DM

D, M

S, M

HP

E

University of M


entistry 4

7. Orient the bur at 3 degrees from

the long axis of the tooth. 7. O

rient the bur at 3 degrees from the long axis of the tooth.

8. With the sw

eeping movem

ent, proceed to remove the buccal tooth

structures at a predetermined depth by rem

oving the islands of tooth structure betw

een depth grooves.

8. W

ith the sweeping m

ovement, proceed to rem

ove the buccal tooth structures at a predeterm

ined depth by removing the islands of tooth

structure between depth grooves.

9. Make sure you rem

ove all the natural undercut9.

Make sure you rem

ove

R

anier M. A

darve, DM

D, M

S, M

HP

E

University of M


entistry 5

all the natural undercut on unprepared tooth (Fig. 7).

Fig. 7. R

emoval of U

ndercuts

10. Re-orient your bur angulation to reduce the second plane of the buccal

surface. 11. Follow

the outline of the unprepared buccal contours (Fig. 8).

Fig. 8. Second Plane of Buccal Surface

Full Crow


R

anier M. A

darve, DM

D, M

S, M

HP

E

University of M


entistry 5


ity and the amount of buccal reduction (Fig. 9) by:


ity and the amount of buccal reduction (Fig. 9) by:



Fig. 9. B

uccal Surface Reduction

13. R

epeat the same procedure on the lingual surface m

aking sure that the orientation of bur is at 3 degrees and extending the reduction apically upto 1.0 m

m to the m

argin of the gingiva. There is, however, no second plane

13. Repeat the sam

e procedure on the lingual surface making sure that the

orientation of bur is at 3 degrees and extending the reduction apically upto 1.0 m

m to the m

argin of the gingiva. There is, however,

R

anier M. A

darve, DM

D, M

S, M

HP

E

University of M


entistry 6

no second plane for the lingual surface (Fig. 10)

Fig. 10. Lingual Surface R

eduction

14. Verify the rem

oval of undercut (Fig. 11) and the amount of lingual

reduction by: a. The silicone putty m

atrix

Fig. 11. Rem

oval of Undercut

Full Crow


R

anier M. A

darve, DM

D, M

S, M

HP

E

University of M


entistry 6

15. At this point w

e can begin developing our cervical margin by extending

apically the margin from

1.0 mm

to 0.5mm

above the margin of the

gingiva. The margin configuration is cham

fer. How

ever, completion of the

cervical margin preparation can be done after reduction of all axial

surfaces of the tooth.

C

. Proximal Surface R

eduction The goals of proxim

al reduction are to (1) eliminate proxim

al contact with the

adjacent teeth, and (2) create sufficient convergence to the occlusal surface.

16. Initial proximal cuts can be m

ade with a sm

aller diameter round-end

tapered diamond bur (Fig.12).

Fig. 12. Initial Proxim

al Reduction w

ith sm

aller diameter bur

17. In a saw

ing motion the thin diam

eter diamond bur is w

orked through the proxim

al area in occlusogingival and buccolingual direction. You can do

this both in the mesial and distal surfaces.

18. Avoid contact w

ith the adjacent teeth. 19. O

nce sufficient maneuvering room

has been obtained, use the larger diam

eter round-end diamond bur to plane the w

alls and extending apically form

ing the chamfer m

argin at 0.5 mm

above the margins of the gingiva

(Fig. 13).

Fig. 13. Proximal R

eduction with larger

diameter bur

Full Crow


R

anier M. A

darve, DM

D, M

S, M

HP

E

University of M


entistry 7

20. Maintain the taper of each surface at 3 degrees.

20. Maintain the taper of each surface at 3 degrees.


ity and the amount of proxim

al reduction by visually exam

ining the 3 degrees taper, the 0.5mm

chamfer m

argin and absence of tooth contact on the adjacent teeth (Fig. 14).


ity and the amount of proxim

al reduction by visually exam

ining the 3 degrees taper, the 0.5mm

chamfer m

argin and absence of tooth contact on the adjacent teeth (Fig. 14).

Fig. 14. Proxim

al Surface Reduction

D. Functional C

usp Bevel

D. Functional C

usp Bevel

The goal of functional cusp bevel is to reduce further the cuspal height by 0.5 The goal of functional cusp bevel is to

R

anier M. A

darve, DM

D, M

S, M

HP

E

University of M


entistry 8

reduce further the cuspal height by 0.5 m

m on the functional cusp to provide adequate thickness of the restorative

material on the area of significant functional loading.

22. U

sing the round-end tapered bur, depth grooves are placed at 45 degrees to the long axis of the tooth at the line angle created betw

een the second plane of the buccal surface and occlusal surface (Fig. 15).

Fig. 15. B

ur Angulation for Functional C

usp Bevel

23. W

ith the sweeping m

ovement, proceed to rem

ove tooth structure to the predeterm

ined depth by removing the islands of tooth structure betw

een depth grooves.

Full Crow


R

anier M. A

darve, DM

D, M

S, M

HP

E

University of M


entistry 8

24. Follow the up and dow

n contours of the cusp heights. 24. Follow

the up and down contours of the cusp heights.

25. A w

ide bevel should have been created on the area (Fig. 16). 25. A

wide bevel should have been created on the area (Fig. 16).

Fig. 16. Functional C

usp Bevel

E. M

argin Preparation E. M

argin Preparation The goal of m

argin preparation is to establish a visible termination of the

The goal of margin preparation is to

R

anier M. A

darve, DM

D, M

S, M

HP

E

University of M


entistry 9

establish a visible termination of the

preparation that provides a definite finish line configuration. A cham

fer configuration is required for FG

C. The dim

ension is 0.5 mm

and is placed 0.5m

m supragingival all around the cervical area of the prepared tooth.

26. W

ith a depth of 0.5mm

, placed the round-end tapered bur 0.5 mm

above the m

argin of the gingiva and define the rough removal of teeth structure

previously performed along the cervical m

argin of the tooth. 27. Follow

the contour of the margin of the gingiva.

28. Rem

ove any rough and uneven surface along the margin.

29. Assure a sm

ooth, even, definite chamfer m

argin (Fig. 17).

Fig. 17. Cham

fer Margin Preparation

Full Crow


R

anier M. A

darve, DM

D, M

S, M

HP

E

University of M


entistry 9

F. Finishing the Preparation F. Finishing the Preparation The goals of finishing the preparation are to (1)establish a sm

ooth preparationThe goals of finishing the preparation are to

R

anier M. A

darve, DM

D, M

S, M

HP

E

University of M


entistry 10

(1)establish a smooth preparation

devoid of irregularities (2) establish a well-defined and sm

ooth margin

configuration.

30. With the round-end tapered bur, sm

oothen all the axial surfaces of the preparation particularly rem

oving all surface irregularities. 31. R

ound off all the sharp corners and areas 32. For the m

argins, use the round-end tapered finishing bur (fine-grit), to rem

ove surface irregularities and provide smooth and w

ell-defined margin

finish (Fig.18).

Fig. 18. Finishing the Preparation

Fig. 19 A. B

uccal View

Fig. 19 B. Lingual View

Fig. 19 A to C

. Tooth P

reparation on Tooth # 30 to receive Full G

old Crow

n

Fig. 19 C. O

cclusal View

Full Crow


R

anier M. A

darve, DM

D, M

S, M

HP

E

University of M


entistry 10

O

cclusal Reduction

1.0 m

m

P

rovide Adequate

Occlusal C

learance

Occlusal P

lanar R

eduction

FGC

#30

Preparation Finish

Rem

ove sharp area

Sm

ooth the surfaces

Functional Cusp B

evel

Additional 0.5 m

m reduction

Located at Functional C

usp

Second Plane of B

uccal R

eduction

Follows the anatom

ical contour

Lingual R

eduction

Rem

ove anatomical

undercut

3-de gree taper

B

uccal Reduction

R

emove anatom

ical undercut

3-de gree taper

Cham

fer Margin (Lingual)

0.5 m

m reduction

0.5 m

m above the

margin of the gingiva

Cham

fer Margin (B

uccal)

0.5 mm

reduction

0.5 mm

above the margin

of the gingiva

C

hamfer M

argin (Interproxima)

Follow

s the anatomical

contour of the margin of

gingiva

Provide sm

ooth transition in the interproxim

al area

G

eneral Features of Full G

old Crow

n (FGC

) Preparation for Posterior

Teeth

Full Crow


R

anier M. A

darve, DM

D, M

S, M

HP

E

University of M


entistry 11

R

anier M. A

darve, DM

D, M

S, M

HP

E

University of M


entistry 11

IV. Evaluating the Preparation C

heck your preparation using your silicone putty matrix. V

isually inspect your preparation and evaluate your reductions on all the surfaces. U

se the evaluation criteria. B

elow are som

e guide questions that may be helpful to determ

ine the correctness of your preparation. Y

ou may go back to your preparation if there is

a need to modify.

1. O

cclusal Reduction

a. Do you have 1.0 m

m occlusal reduction? M

ore? Less? b. D

id you follow the contours of the occlusal surface? Is it flat?

2. Buccal and Lingual R

eductions a. Is there an undercut left/ created? b. D

o you have 3 degrees taper on each surface? More? Less?

c. D

o you have the second plane on your buccal surface? 3. P

roximal R

eduction a. D

id you eliminate the contact w

ith the adjacent teeth? b. D

o you have sufficient occlusal convergence? 4. Functional C

usp Bevel

a. Did you provide an additional 0.5 m

m reduction on the

functional cusp? b. Is it located in the area w

here functional loading occur? 5. M

argin Preparation

a. Do you have a 0.5 m

m cham

fer margin configuration?

b. Is located 0.5 mm

above the margin of the gingiva and follow

ing its contour?

6. Finishing the preparation a. Is your preparation sm

ooth and devoid of irregularities? b. Is your m

argin well-defined and sm

ooth C

ON

GR

ATU

LATIO

NS! You m

ade it! You have finished Level 1 of the Full

Crow

n Module. Y

ou may proceed doing the M

odule Extensions. In the

extensions, you will prepare different teeth to receive different type of

restorations. This will expand your understanding of the principles that w

ere covered in this m

odule and provide you with further practice and develop

efficiency. Carry on!

Full Crow


R

anier M. A

darve, DM

D, M

S, M

HP

E

University of M


entistry 12

Instructors Notes on M

odule Extensions Level 1 The m

odule extensions in level 1 are designed to further enhance your dexterity skills in teeth preparation not only for posterior teeth but also for anterior teeth. A

lso more im

portantly, for you to have an understanding of the difference of the preparation design for the specific type of restorative m

aterial (FGC

, PFM

, all-ceramic). In a nut-shell, each preparation varies in the

amount of tooth reduction and the m

argin design , and I want you to take note of that.

Porcelain Fused to Metal (PFM

) / 12

1. Set up your articulated tooth. Fabricate a silicone index.

2. Prepare your tooth. The preparation for full crow

n on tooth #12 to receive a P

FM follow

s the same steps and sequence as the

preparation for FGC

in this module. H

owever, the am

ount of reduction is generally greater than FG

C. The follow

ing are the major differences:

a. Occlusal reduction 1.5 m

m

b. Buccal reductions-

- 1.3 mm

and 3-degree taper -

Two-plane reduction required

c. Lingual reductions- 1.0 m

m and 3-dgree taper

d. Proxim

al reductions- no proximal contact, no undercut and

sufficient convergence e. Functional cusp bevel- 0.5 m

m m

ore on the functional cusp f.

Margin preparation-

- 1.3 mm

shoulder margin on the facial

- 0.5 m

m cham

fer margin on the lingual

- 0.5 m

m above the m

argin of gingiva -

Sm

ooth transition of chamfer and shoulder m

argins along the interproxim

al area g. Finishing your preparation round off sharp angles and provide

a smooth finish on the tooth.

3. Evaluate your preparation

C

linical Relevance

Porcelain Fused to M

etal (PFM

) crown is a restoration that covers the entire clinical crow

n of a tooth w

ith both metal and porcelain m

aterial. Porcelain is incorporated in the area w

here there is esthetic concern. This is generally on the labial area, proxim

al area (most often on the m

esial), occlusal area but rarely on the lingual cervical area. The porcelain coverage thus requires m

ore teeth reduction to provide adequate thickness for strength and esthetics. M

inimal tooth reduction

is required on the lingual where there is no porcelain coverage and thus conserves m

ore tooth structures. Full C

rown M


Ranier M

. Adarve, D

MD

, MS

, MH

PE

U


chool of Dentistry

13

M

argin Junction (Interproxima)

Follow

s the anatomical

contour of the margin of

gingiva

Provide sm

ooth transition betw

een shoulder and cham

fer in the interproximal

area

R

anier M. A

darve, DM

D, M

S, M

HP

E

University of M


entistry 14

PFM #12

Occlusal R

eduction

1.5 mm

Provide A

dequate O

cclusal Clearance

O

cclusal Planar

Reduction

Lingual Reduction

R

emove anatom

ical undercut

3-de gree taper

Buccal R

eduction

Rem

ove anatomical

undercut

3-de gree taper

Shoulder Margin (B

uccal)

1.3 mm

reduction

0.5 mm

above the margin

of the gingiva C

hamfer M

argin (Lingual)

0.5 mm

reduction

0.5 mm

above the m

argin of the gingiva

Second Plane of Buccal

Reduction

Follow

s the anatomical

contour Functional C

usp Bevel

A

dditional 0.5 mm

reduction

Located at Functional C

usp

Preparation Finish

Rem

ove sharp area

Sm

ooth the surfaces

General Features of

Porcelain Fused to Metal

(PFM) C

rown Preparation for

Posterior Teeth

Full Crow


R

anier M. A

darve, DM

D, M

S, M

HP

E

University of M


entistry 14

All C

eramic C

rown / 8

1. S

et up your articulated tooth. Fabricate a silicone index. 2. P

repare your tooth. The preparation for full crown on tooth #8 to

receive an All C

eramic restoration follow

s the same steps and

sequence as the preparation for FGC

in this module. H

owever, the

amount of reduction is generally greater than FG

C. The follow

ing are the m

ajor differences: a. Incisal reduction 2.0 m

m

b. Labial reductions- -1.5 m

m and 3-degree taper

-Two-plane labial reduction required

c. Lingual Fossa reductions- 1.3 m

m

d. Cingulum

Reduction- 1.5 m

m on m

argin and preserve as much

cingulum height

e. Proxim

al reductions- no proximal contact, no undercut and

sufficient convergence f.

Margin preparation-

- 1.5 m

m shoulder m

argin on the labial -

1.5 mm

shoulder margin on the lingual

- 0.5 mm

above the margin of gingiva

- Sm

ooth transition margins along the

interproximal area

g. Finishing your preparation round off sharp angles and provide a sm

ooth finish on the tooth. h. E

valuate your preparation

Clinical R

elevance A

ll ceramic restoration is an esthetic restoration. It is a restoration of choice for patients that

demands higher esthetic requirem

ents. Esthetics can be achieved w

ith this type of restoration because unlike P

FM, it does not have a m

etal substructure that affects the light translucency and can have the potential to m

imic the translucency of a natural tooth. H

owever, the m

ain drawback

of this restoration is its fracture resistance. It fractures easily thus care should be done in preparing the tooth and you should provide adequate thickness of porcelain for strength. Its use is recom

mended for anterior teeth though it can also be indicated for posterior teeth in w

ell selected clinical cases. Full C

rown M


Ranier M

. Adarve, D

MD

, MS

, MH

PE

U


chool of Dentistry

15

Margin Junction (Interproxim

a)

Follows the anatom

ical contour of the m

argin of gingiva

P

rovide smooth transition in

the interproximal area

Incisal Reduction

2.0 m

m

P

rovide Adequate Incisal

Clearance

Cingulum

Reduction

P

reserve Cingulum

H

eight and taper

Second Plane of Labial R

eduction

Follows the anatom

ical contour

Lingual Fossa Reduction

1.3 m

m reduction

Shoulder Margin (B

uccal)

1.5 mm

reduction

0.5 mm

above the m

argin of the gingiva

Shoulder Margin (Lingual)

1.5 m

m reduction

0.5 m

m above the

margin of the gingiva

Labial Reduction

R

emove anatom

ical undercut

3-de gree taper

Preparation Finish

Rem

ove sharp area

Sm

ooth the surfaces

General Features of A

ll C

eramic C

rown Preparation

for Anterior Teeth

ALL C

ERA

MIC

#8

Full Crow


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anier M. A

darve, DM

D, M

S, M

HP

E

University of M


entistry 16

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anier M. A

darve, DM

D, M

S, M

HP

E

University of M


entistry 16

Full Crown

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