7. Onlay Procedure Flashcards by J L

An onlay is:
vA restoration that restores the ____ surface of the tooth as well as one or more ____
vA restoration that restores the ____ and ____ surfaces of the crown of the tooth
vA restoration that involves one or both ____ surfaces

occlusal
cusps
internal
external
proximal

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An onlay is:
vConsidered an ____ and ____ restoration
vIt is an ____ procedure

intracoronal
extracoronal
indirect

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Extracoronal Restorations and Occlusion:

vOcclusal forces transmitted through an onlay restoration, tend to hold the cusps together because the ____ have been incorporated into the restoration

cusps

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Onlay Indications

v Indicated when the buccal or lingual isthmus outline is ____ the distance from the central groove toward the cusp tip

two-thirds

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Onlay Indications
v Indicated when the buccal-lingual isthmus width is more than ____ the distance between the buccal and lingual cusp tips

half

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Onlay Indications
v Necessary for adequate ____ form – to overlay a ____ cusp

or a ____ cusp

resistance
weakened
broken

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Onlay Indications

v Can replace broken cusps when there still is remaining enamel supported by ____ on the buccal and/or lingual surfaces.

dentin

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Onlay vs. Crown

v Can be a ____ alternative to a full coverage crown

conservative

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Onlay Preparation vs. Crown Preparation
v A more ____ preparation than a crown preparation
v Onlay has ____ margins -
vless ____ to gingiva than full crown preparation

conservative
supragingival
irritating

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Onlay Contraindications

Choose full coverage crown when:
v The onlay preparation final margin areas would be in areas of ____
v The remaining buccal and lingual tooth structure is without ____

decalcification

supporting dentin

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Advantages
v Preserves ____ structure – less reduction than a crown
v Prevents the ____ that may lead to fracturing of fragile cusps
vMore precise ____ over contours and contacts
vImproved access and visibility
• Fabricated on a ____ outside the mouth

tooth
stresses
control
die

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Disadvantages of an Onlay
v Multiple \_\_\_\_
v \_\_\_\_ (interim) restoration 
v Laboratory \_\_\_\_
v \_\_\_\_ sensitive

appointments
provisional
cost
technique

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Onlay Options
v ____
v ____

cast gold

porcelain

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Porcelain Onlay
Porcelain onlay preparation maxillary first molar

Buccal view of completed onlay

YAY

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Porcelain Onlay

Indications specific to Porcelain Onlays:
v Areas of ____ importance
v Areas of ____ defects or failing previous restorations
v ____ sized lesions

esthetic
large
moderate

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Porcelain Onlay

Contraindications specific to Porcelain Onlays
v Areas of heavy ____ wear
v ____ history
v Lack of ____ enamel
v Inability to maintain a ____ field
v Deep ____ preparations
• Want gingival margins in ____ – best bond

occlusal
bruxism
occlusal
dry
subgingival
enamel

Specific Advantages of Porcelain Onlays
Ability to strengthen remaining tooth structure
v____ bonded
vReduced ____ vs large composite restoration

adhesively

polymerization shrinkage

Specific Disadvantages of Porcelain Onlays
v ____ of porcelain onlays:
vCeramic can fracture without adequate ____ vCan fracture during ____ in or after cementation
vWears ____ dentition and restorations
• Particularly if ____ and unpolished

brittleness
thickness
try
opposing
rough

Porcelain Onlay Preparation

vTooth reduction varies between ____ and non functional cusps
vReduction will mimic ____ anatomy of the cusp being reduced
vAll areas should have a common ____
• All walls are ____

functional
original
path of draw
divergent

Porcelain Onlay Preparation

1. Prepare an “overcut” MOD preparation 
\_\_\_\_ or tapered diamond bur
\_\_\_\_ mm isthmus buccolingually
\_\_\_\_ mm depth
\_\_\_\_ walls
2. Use tapered fissure bur remove \_\_\_\_
3. Internally \_\_\_\_ angles are important

171
2-3
2
divergent
undercuts
rounded

Porcelain Onlay Preparation

Proximally, extend to just break ____
Check all areas have common path of
draw-____
NO ____ - ____
joint cavosurface
NO ____ contacts in MIC directly on ____ areas

contact
divergent
bevels
butt
occlusal
margin

Porcelain Onlay Preparation

9. Occlusal reduction/cusp reduction:
v use tapered fissure bur (171)
v Follow \_\_\_\_ planes of occlusal anatomy 
v Reduction:
• Functional cusp: \_\_\_\_ mm
• Non functional cusp: \_\_\_\_ mm

geometric
2
1.5

Porcelain Onlay Preparation
Occlusal reduction
v Follow original ____ contours

cuspal

Porcelain Onlay Preparation

Check occlusal reduction in MIP and excursion
-Use a softened piece of ____ to check the bite: Make an imprint of the bite in MIP and measure the wax ____ with a periodontal probe where the cusp used to be

pink wax

thickness

Porcelain Onlay Preparation 10. Occlusal shoulder - On the ____ surface of the cusp being covered v Added with tapered fissure bur v ____ mm wide axially v Placed in the ____ third of the cusp O/G v ____ joint – NO ____

``` outer 1-1.5 middle butt bevels ```

Porcelain Onlay Preparation ____ external and internal angles ____ mm axial reduction ____ joint shoulder margin ____ mm non functional (L) cusp occlusal reduction

rounded 1-1.5 butt 1.5

Procedure for Porcelain Onlay ____ mm non functional cusp (L) shoulder reduction Check with ____ mm hatchet width ____ mm proximal contact opening Check with ____ mm hatchet thickness

1 small 1 0.75 small 1.0

Procedure for Porcelain Onlay ____ mm non functional cusp (L) occlusal reduction Check with ____ in MIP to measure occlusal reduction

1.5 | pink wax

Summary v An excellent alternative to direct composite restorations v More ____ than full-coverage restorations v Very ____ sensitive • Proper case selection • Operator skill • Attention to detail

conservative | technique

Provisional Restoration vAn ____ restoration cemented into the preparation until the final restoration is delivered v“Temporary” – ____ more correct vMade of ____ or composite materials

interim provisional acryclic

Provisional Restoration A Provisional should: v____ the tooth vmaintain the health of periodontium vmaintain the ____ of the prepared tooth in the arch vmaintain position of ____ and opposing teeth

protect position adjacent

``` Provisional Restoration A Provisional should (continued): vprovide ____, phonetic, and masticatory functions vhave adequate ____ and retention vnot be ____ ```

esthetic strength irritating

Provisional Restoration Composite Resin Procedure vBefore tooth preparation, roll hard body ____ putty into a hot dog shape and place it on the tooth being prepared to make an impression. vCapture the tooth and both ____ teeth in the impression v“____”

polyvinyl siloxane adjacent putty shell

Provisional Restoration Composite Resin Procedure vLubricate preparation with ____. Use a brush and coat the tooth well vPlace composite provisional material into molded putty shell

vaseline

Provisional Restoration Composite Resin Procedure vSeat Putty shell fully onto preparation vWait ____ minutes -Remove putty shell from arch -Refine Carefully trim away excess

1.5-2

Provisional Restoration Composite Resin Procedure vVERY carefully perform minor last adjustments on the prepared tooth vDO NOT DAMAGE THE TOOTH OR THE PREPARATION

YAY

Provisional Restoration Composite Resin Procedure Final try in and margin check Check and adjust occlusion

YAY

Provisional Restoration Composite Resin Procedure Provisional is cemented with a “temporary” ____ cement

non-eugenol