FP 16 - Partial Coverage Restorations (Dr. Filokyprou)

What are the 3 types of partial coverage restorations?

- Veneers

- Inlays

- Onlays

What are the following indications for?

- Missing cusps

- Gross caries causing an unsupported cusp

- Protection of posterior endodontically treated teeth

- Cracked teeth (to encircle the tooth)

- Caries associated with preexisting indirect restoration causing weakened cusps

- Worn teeth with moderate to severe dentin exposure

Indirect restorations

What are the following contraindications for?

- Patients with uncontrolled high caries risk

- Removing sound tooth structure that could be preserved

- Patients with TMD Symptoms

- Teeth with a poor or guarded prognosis

Indirect restorations

All of the following are indications for partial coverage restoration EXCEPT:

A. teeth with small to moderate loss of tooth structure

B. Class II restoration with low caries rate

C. Enamel preservation

D. Esthetic is not a concern

E. Cuspal coverage

D- ESTHETIC RESTORATION IS REQUIRED

All of the following are advantages of partial coverage restorations EXCEPT:

A. Conservation of tooth structure

B. Increased pulpal and periodontal insult

C. Less marginal leakage

E. Potential for chair-side fabrication (In-office milling)

E. Indirect fabrication

F. Eliminates potential operator error

G. Reduces polymerization shrinkage

B - REDUCED pulpal and periodontal insult

All of the following are contraindications of partial coverage restorations EXCEPT:

A. Patients with poor oral hygiene or active caries

B. Moderate bruxism

C. Insufficient remaining tooth structure/ More than 2/3 of the occlusal table requires restoration

B - SEVERE bruxism

All of the following are DISADVANTAGES of partial coverage restorations EXCEPT:

A. Technique sensitivity

B. Cost/ Associated lab fee

C. Less Visits

D. Potential abrasiveness

E. Wear of the composite resin luting agent

F. Challenging occlusal adjustment

G. Less accessible inter proximal area

C - MORE VISITS

What type of retention?

Rely on bonding to enamel, conservative technique (eg porcelain laminate veneers, ceramic inlays)

Adhesively retained

What type of retention?

Rely on opposing axial walls of certain geometric shapes within the tooth preparation for mechanical retention (eg. 3/4 crowns, gold inlays/ inlays)

Cohesively retained

What type of cast partial coverage restoration?

3/4 crown

What type of cast partial coverage restoration?

Modified 3/4 crown

What type of cast partial coverage restoration?

7/8 crown

What type of cast partial coverage restoration?

3/4 crown

What type of cast partial coverage restoration?

Pinledges

What type of material is typically used today for partial coverage restorations?

Ceramic

Define the following:

A restoration that restores one or more cusps and adjoining occlusal surfaces or the entire occlusal surface and is retained by mechanical or adhesive means

Onlay

What type of restoration?

Onlay

What type of restoration?

- Adhesively luted, characterized by a defect-specific, less retentive preparation

- Conservative preparation, reduced loss of hard tooth tissues

Onlay

What are the 3 materials used for inlays/onlays?

- Glass matrix ceramics (Leucite-based/ lithium disilicate)

- Polycrystalline (zirconia)

- Resin-matrix ceramics

All of the following are TRUE regarding onlay preparation EXCEPT:

a. Occlusal reduction 1.5-2mm

b. Preparation margin 1mm

c. Smooth surfaces

d. Rounded line angles

e. Precise, flowing finish lines

f. Distinct, smooth chamfer margins on enamel

g. The margins of the restoration should not be at a centric contact

h. Proximal clearance, supra gingival margins, no beveled margins

i. Ensure adequate material thickness

j. Remove/block undercuts

a. Occlusal reduction 1-1.5mm

What is the limit of most milling machines?

0.5-0.6mm

(Few manufacturers can use 0.3mm round burs during the milling of zirconia)

In onlay preparation, we want a cervico-occlusal wall divergence of ______ degrees

10-12 degrees

What are two direct ways for onlay temporization?

- Separating medium

- Clear template

What are the steps for onlay try in? (7)

- Check the shade

- Check inter proximal contacts

- Check internal fit using fit-checker

- Verify seating via BW radiograph

- Do NOT adjust occlusion —> fracture risk

- Polish all the adjusted areas

- Achieve isolation

Can occlusal adjustments for onlays be done at the try in before bonding?

No - do not adjust occlusion, FRACTURE RISK!!

Can occlusal adjustments for onlays be done after cementation?

Yes - adjust occlusion, polish margins, & adjusted areas

All of the following are onlay complications EXCEPT:

A) Marginal discoloration

B) Marginal crack formation

C) Occlusal wear

D) Biological complications

E) Debonding

F) Secondary caries

G) Need for endo tx

G) Need for endo tx

What is the onlay survivial rate after 5 years?

95%

What is the onlay survivial rate after 10 years?

91%

What is the overall onlay survivial rate?

95.27%

Define the following:

The layer of material placed over a tooth, which improves the esthetics of smile and/or protects the tooth's surface from damage

Veneer

The following are indications for ______

- Discoloration

- Major morphologic modifications

- Malpositioned teeth

- Enamel defects

- Aging

- Generalized congenital and acquired malformations

Ceramic veneers

What are some examples of discoloration that indicates a ceramic veneer? (5)

- Tetracycline staining

- Fluorosis

- Extrinsic Staining

- Aging

- Teeth resistant to bleaching

What are two examples of morphological modifications that indicate a ceramic veneer?

- Diastema and Interdental Triangles

- Augmentation of the Incisal length and prominence

With aging, a thinner enamal indicates _______ flexure

More

What are three examples of enamel defects that indicate a ceramic veneer?

- Hypoplasia

- Malformations (Peg laterals)

- Loss of tooth structure

What are two examples of malpositioned teeth that indicate a ceramic veneer?

- Rotated or malpositioned

- Orthodontic can be an alternative or adjunctive treatment option, but many patients do not wish to undergo longer treatment with orthodontics

What direction is the path of insertion for veneers?

Horizontal

What direction is the path of insertion for crowns?

Vertical

What are the 2 workflows for creating veneers?

- Direct

- Indirect

What are the disadvantages of direct veneers?

- Microleakage

- Susceptibility to stain

- Poor wear resistance

- Technique sensitive

Advantages of Indirect Ceramic Veneers:

- Color

- Bond Strength

- Periodontal Health

- Resistance to abrasion

- Inherent porcelain strength

- Resistance to fluid absorption

- Esthetics

Disadvantages of Indirect Ceramic Veneers:

- Time

- Repair

- Technique-sensitive

- Color

- Tooth preparation

- Fragility

- Cost

All of the following are contraindications for veneers EXCEPT:

A. Sufficient enamel

B. Oral habits

C. Bruxism

D. Insufficient tooth structure

a - INSUFFICENT ENAMEL

What are the three indirect veneer materials?

- Feldspathic porcelain

- Lithium Disilicate (pressed or CAD)

- Polycrystalline (Zirconia)

What are three methods of fabrication for indirect veneer materials?

- Sintering technology on a platinum foil or a refractory die

- Pressing techniques

- CAD/CAM

What method of fabrication for indirect veneer materials?

- Superior esthetics

- Relatively low strength

Sintering on platinum foil or refractory dies

What method of fabrication for indirect veneer materials?

- Reduced esthetics

- Highest strength

Monolithic, stained (Pressed or CAD/CAM)

What method of fabrication for indirect veneer materials?

- Good esthetics

- High strength

- Reduced space

Cut-back technique, minimal veneering on a framework designed as a dentin core (Pressed or CAD/CAM)

What method of fabrication for indirect veneer materials?

- Very good esthetics

- High strength

- More space available

Layered with extensive veneer of a framework (Pressed or CAD/CAM)

What could we make to check esthetics, function, and show an example to the patient?

Mock up

What are you analyzing for the following?

- Interpupillary line

- Intercommissure line

- Facial midline

Frontal extra-oral evaluation

What are you analyzing for the following?

- Rickett's E Plane

- NSP (Nasiolabial angle)

Profile

What are you analyzing for the following?

- Maxillary midline

- Incisal plane

Smile analysis (extra-oral)

What are you analyzing for the following?

- Phonetics

- VDO

Functional

What are you analyzing for the following?

- Buccal corridors

- Smile line

- Gums

- Lips

Smile analysis (intra-oral)

What are you analyzing for the following?

- Gingival zenith

- Gingival levels

- Papilla

Gingiva

What are you analyzing for the following?

- Propotions

- Long Axis

- IDC

- Line Angles

- Shape

- Surface Texture

- Shade

- Incisal plane curve

- Incisal plane

Teeth

The following are objective criteria for what?

- Gingival Health

- Balance of gingival levels

- Gingival zenith

- Interdental closure

- Level of interdental contact

- Tooth axis

- Relative tooth dimensions

- Basic features of tooth form

- Tooth characterization

- Surface texture

- Color

- Incisal edge configuration

- Lower lip line

- Smile symmetry

- Midline and occlusal plane orientation

Dental esthetics

What factors go into diagnosis and treatment planning for veneers?

- Checking each tooth individually

- Facial and smile analysis

- Occlusal analysis

- Patient's expectations

The following are objectives for what?

- Determine Incisal Edge Position

- - Length

- - Bucco-lingual position

- Incisal Plane & Occlusal plane

- Esthetic Proportions

- Establish adequate occlusal scheme

Smile Design/ Diagnostic Wax Up

What options do you have in determining the incisal edge Position for a patient?

- Free-hand

- Wax-up

- CAD

How can you check a mock-up? (4)

- Check the design intra-orally (esthetics & function)

- Making changes and finalizing the design

- Communication with the patient and motivation

- Defining tooth preparation

When preparing a tooth for veneers, all margins should be finished on:

A) Enamel

B) Dentin

C) Pulp

D) Cementum

A) Enamel

If margins for veneers are located on ______, complete coverage restoration is recommended

Cementum

What is the suggested preparation reduction for the incisal edge for a veneer?

1-2mm

What is the suggested preparation reduction at the cervical 1/3 for a veneer?

0.3mm

What is the suggested preparation reduction at the middle 1/3 for a veneer?

0.5-0.7mm

What is the suggested preparation for the chamfer margin for veneers?

0.3-0.5mm

What are two ways to do a guided preparation? (2)

- Preparation guide

- Preparation through the mock up

Generally a depth of ____mm is needed to change the color of the tooth by one shade

0.2mm

When using a depth cutter, to reach the necessary depth in Cervical and incisal thirds, the bur should be used in __ different angulations/planes

3

What has the following characteristics?

- Can only penetrate until the non-cutting shaft is flush with the tooth surface

- To reach the necessary depth in cervical and incisal thirds the bur should be used in three different angulations

Depth cutters

What type of incisal preparation?

Feathered incisal edge (window or bevel)

What type of incisal preparation?

Butt joint or mini chamfer

What type of incisal preparation?

Palatal chamfer

For an incisal preparation, it is important to avoid the contact point at least ___mm above or below

1mm

Feathered edge and palatal chamfer preparations caused a reduction in the ________ of the teeth

Strength

_________ preparation was more susceptible to ceramic fractures

Palatal chamfer

Which preparation least affected the strength of teeth?

Butt joint

Incisal edge reduction should be done to create a butt incisal finish line with lingual inclination of ___⁰. This improves esthetics & Improves mechanical properties

75°

For Suprangingival, Equigingival, Intrasulcular, there should be a shallow, thin chamfer finish line of ____-____mm

0.3-0.5mm

Define the following:

The most apical point of the gingival contour, which lies distal to the main tooth axis

Zenith of gingival margin

Where should the cervical preparation be placed for veneers?

Equigingival or up to 0.5mm intrasulcular preparation is recommended

Define the following:

This preparation is suitable for more extensive morphologic changes, for closing interdental spaces, for covering exposed dentin/ root or existing composite fillings, or when a considerable difference in color exists

Intrasulcular preparation

What can you use as a guide to prepare the facial/labial surface of a veneer?

Horizontal depth cuts

Where should a short wrap occur for interproximal preparation for veneers?

Facial to the contact area, visible

What does a medium wrap do for interproximal preparation for veneers?

Hides the margin in the inter proximal niches but retains the contact points

What does a long wrap do for interproximal preparation for veneers?

Opens the contact points, indicated when major changes of form, closures of diastema/ interdental triangles are planned

Preparation of the proximal surface should be extended to include the _______ area

Proximal sub-contact

Define the following:

- Shade of the tooth after preparation

- This will give the lab tech an idea about the darkness of the substructure to determine the amount of the opaque layer needed to mask

Stump shade

Which of the following is paired CORRECTLY?

A) Facial to the contact area, visible = short wrap

B) Hides the margin in the inter proximal niches but retains the contact points = medium wrap

C) Opens the contact points, indicated when major changes of form, closures of diastema/interdental triangles are planned = long wrap

ALL ANSWER CHOICES

What is the suggested prep depth for a veneer if you want to shade change from A4 to A1?

0.9mm

What is the suggested prep depth for a veneer if you want to shade change from A2 to A1?

0.5mm

What is the suggested prep depth for a veneer if you want to shade change from A1 to A1, just fixing the shape?

0.3mm

What has the following characteristics?

- Silicon mold of the wax-up

- Cover prepared teeth with separating medium

- Apply temporary material

Provisionalisation

What has the following steps?

1) Spot etching with 37% PA for 20''

2) Rinse with water and air-dry

3) Apply dentin bonding agent, light cure for 10 seconds

4) Clean the intaglio of temporaries

5) Rinse with water and air-dry

6) Apply dentin bonding agent on intaglio surface and then flowable resin composite

Provisionalisation

Fracture resistance of ceramics bonded with resin cements is significantly ________

Increased

What type of cements are recommended for veneer cementation?

Light-cured only cements

Why are light-cured only cements recommended for veneer cementation?

Amines in self-cure materials discolor