Dental Restorations: Inlay and Onlay

Study Flashcards Play Quiz

Questions and Answers

Why is it not necessary to remove undermined enamel when preparing a tooth for a composite resin restoration?

Because it can be blocked out with glass ionomer prior to final preparation and impression

What is the purpose of providing convenience access for the restoration?

To facilitate easy restoration and maintenance

What is the recommended reduction for a functional cusp?

2.0 - 2.5 mm

Why is it important to evaluate affected dentin?

To determine the extent of caries Signup and view all the answers

How should the margins be finished in both capping and shoeing?

Flat and smooth Signup and view all the answers

What is the ideal width of the isthmus?

1.5 - 2.0 mm Signup and view all the answers

What determines the depth of the pulpal floor?

The planned restored anatomy Signup and view all the answers

What is the purpose of divergent axial walls in preparations?

All of the above Signup and view all the answers

Why may the fossa areas need to be deeper?

To accommodate a deeper depth of the restoration Signup and view all the answers

Why do walls not need to be parallel in these preparations?

Due to retention by adhesion Signup and view all the answers

What determines the proximal extensions of the preparation?

The extent of caries or previous restoration Signup and view all the answers

What is the benefit of increased taper in preparations?

All of the above Signup and view all the answers

What is the purpose of temporization after final impression?

To prevent shifting of teeth and sensitivity Signup and view all the answers

What is the ideal gingival floor depth?

1.0-1.5 mm Signup and view all the answers

What is used to create a temporary fabrication?

All of the above Signup and view all the answers

What is used for directly temporizing a preparation?

A light-cured temporary resin material Signup and view all the answers

What should be done if the restoration does not seat easily?

Check for residual provisional material Signup and view all the answers

How should marginal integrity be checked?

With a sharp explorer Signup and view all the answers

What affects the color of the ceramic restoration?

Shade selection, opacity versus translucency of the ceramic restoration, and opacity versus translucency of the resin luting cement Signup and view all the answers

Why should occlusal contacts be checked after the restoration has been seated?

To prevent restoration fracture Signup and view all the answers

What is the purpose of the silane coupling agent?

To make the etched ceramic reactive to chemically bond to the composite resin Signup and view all the answers

What type of resin is used to link the tooth and restoration interfaces?

Dual cured hybrid resin Signup and view all the answers

What should be done to the restoration after it is received from the lab?

All of the above Signup and view all the answers

What is the purpose of the try-in process?

To test the fit of the restoration Signup and view all the answers

What is the purpose of using a wet slurry of flour pumice, soft bristle brush, or micro air abrasion in cavity preparation?

To clean the cavity preparation Signup and view all the answers

How long should 37% phosphoric acid be applied to the enamel?

15 seconds Signup and view all the answers

What is the purpose of applying a thin layer of unfilled resin or enamel bonding agent?

To allow the reactive silane to bond with the surface Signup and view all the answers

Why is a dual cure capacity composite resin luting agent used for onlay/inlay restorations?

Because of the thickness and opacity of the restoration Signup and view all the answers

What is the minimum thickness of ceramic required in the central fossa?

1.5 mm Signup and view all the answers

What is the purpose of 'tacking' the restoration onto the tooth?

To hold the restoration in place while excess cement is removed Signup and view all the answers

Why is it necessary to avoid pooling during the application of the luting agent?

To prevent the restoration from seating Signup and view all the answers

What is the purpose of applying a thin layer of resin bonding agent to the etched surface of the restoration?

To allow the composite resin luting agent to bond with the surface Signup and view all the answers

What type of restoration is indicated for an extensive preparation that requires strength greater than a composite or amalgam restoration but does not require cuspal coverage?

Inlay Signup and view all the answers

What is the primary difference between an inlay and an onlay?

The extent of cuspal coverage Signup and view all the answers

What is the purpose of beveling the gingival cavosurface?

To remove weakened enamel Signup and view all the answers

What is the ideal degree of beveling for the gingival cavosurface?

30 degrees Signup and view all the answers

What is the purpose of the occlusal dovetail?

To provide additional retention Signup and view all the answers

What is the reduction of nonfunctional cusps for an onlay?

0.75-1.0 mm Signup and view all the answers

What is the recommended height of the shoulder following the lingual or facial axial walls of the cusp?

2.0-3.0 mm Signup and view all the answers

What is the purpose of 'tacking' the restoration onto the tooth?

To hold restoration in place during cementation Signup and view all the answers

What type of resin is used for linking the tooth and restoration interfaces?

Unfilled resin or enamel bonding agent Signup and view all the answers

Why is a dual cure capacity composite resin luting agent used for onlay/inlay restorations?

Due to the thickness and opacity of the onlay/inlay Signup and view all the answers

How long should 37% phosphoric acid be applied to the enamel?

15 seconds Signup and view all the answers

What is the purpose of applying a thin layer of unfilled resin or enamel bonding agent?

To avoid pooling during the application of the luting agent Signup and view all the answers

What is the minimum thickness of ceramic required in the central fossa?

1.5 mm Signup and view all the answers

Why is it necessary to avoid pooling during the application of the luting agent?

To ensure proper seating of the restoration Signup and view all the answers

What is the purpose of applying a thin layer of resin bonding agent to the etched surface of the restoration?

To create a bond between the restoration and the tooth Signup and view all the answers

What is the minimum recommended width of the isthmus to avoid fracture?

2.0 mm Signup and view all the answers

What type of walls are recommended for onlay and inlay preparations?

Divergent Signup and view all the answers

Why are thin areas of ceramic prone to fracture?

Due to insufficient thickness Signup and view all the answers

What is the purpose of rounding all line angles in onlay and inlay preparations?

To reduce stress concentrations Signup and view all the answers

Why is it important to avoid concavities and divots in the floors and walls of onlay and inlay preparations?

To reduce stress concentrations Signup and view all the answers

What is the retention mechanism for onlay and inlay restorations?

Adhesion of resin cement to dentin and enamel Signup and view all the answers

Why are cavosurface margins placed to avoid contact with opposing teeth?

To prevent interferences Signup and view all the answers

What is the characteristic of the prep for onlay and inlay restorations?

Nonmechanically retentive Signup and view all the answers

Why should occlusal contacts be analyzed after the restoration has been seated?

To prevent restoration fracture Signup and view all the answers

What is the purpose of trying in a restoration with a light transmitting medium?

To check the opacity versus translucency of the ceramic restoration Signup and view all the answers

What should be done if the restoration does not seat easily?

Check for residual provisional material Signup and view all the answers

What affects the color of the ceramic restoration?

Shade selection and opacity versus translucency of the resin luting cement Signup and view all the answers

What is the purpose of applying a silane coupling agent to the restoration?

To make the etched ceramic reactive to chemically bond to the unfilled resin layer Signup and view all the answers

What links the tooth and restoration interfaces?

A dual cured hybrid resin luting cement Signup and view all the answers

What should be done to the restoration after it is received from the lab?

Clean the restoration of any debris and coat it with a silane coupling agent Signup and view all the answers

Why is it important to check for residual provisional material?

To prevent the restoration from not seating easily Signup and view all the answers

What is the recommended reduction for a functional cusp in onlay restorations?

2.0 – 2.5 mm Signup and view all the answers

What is the purpose of temporization after final impression?

To avoid shifting of the teeth and sensitivity Signup and view all the answers

What is used to create a temporary fabrication in indirect temporary cementation?

Poured model Signup and view all the answers

How should the margins be finished in both capping and shoeing?

Follow the contour of the cusp tip and ridges Signup and view all the answers

What is the benefit of using a hollow-ground chamfer in onlay restorations?

Better blending of the restoration with tooth structure Signup and view all the answers

What is the purpose of using a non-eugenol temporary cement in indirect temporary cementation?

To allow for easy removal Signup and view all the answers

What is the recommended method for directly temporizing a preparation?

Using light-cured temporary resin material Signup and view all the answers

Why is it important to have divergent axial walls in onlay preparations?

To allow for easier placement and removal Signup and view all the answers

What is the primary indication for an onlay restoration?

Preparations requiring strength greater than composite or amalgam Signup and view all the answers

What is the purpose of beveling the gingival cavosurface?

To remove weakened enamel Signup and view all the answers

What is the ideal degree of beveling for the gingival cavosurface?

30 degrees Signup and view all the answers

What is the purpose of the occlusal dovetail?

To facilitate proximal box preparation Signup and view all the answers

What is the reduction of nonfunctional cusps for an onlay?

0.75-1.0 mm Signup and view all the answers

What is the recommended height of the shoulder following the lingual or facial axial walls of the cusp?

2.0-3.0 mm Signup and view all the answers

What type of restoration is indicated for compromised teeth in high-stress areas?

Gold/metallic onlays Signup and view all the answers

What is the primary difference between an inlay and an onlay?

Onlays require cuspal coverage while inlays do not Signup and view all the answers

What is the primary indication for using ceramic onlays?

Large restorative defects in low stress areas with esthetic concerns Signup and view all the answers

What is the purpose of beveling the gingival cavosurface in onlay preparations?

To remove weakened enamel Signup and view all the answers

What is the recommended occlusal reduction for non-functional cusps in onlay preparations?

0.75-1.0 mm Signup and view all the answers

What is the purpose of the occlusal dovetail in onlay preparations?

To create a retention form Signup and view all the answers

What is the recommended height of the shoulder following the lingual or facial axial walls of the cusp?

2.0-3.0 mm Signup and view all the answers

What type of walls are recommended for onlay and inlay preparations?

Divergent walls Signup and view all the answers

What is the purpose of secondary flaring of the proximal facial and lingual cavosurfaces?

To join the gingival bevel uninterrupted Signup and view all the answers

What is the primary difference between an inlay and an onlay?

Onlays require cuspal coverage, inlays do not Signup and view all the answers

What is the primary consideration for determining the extent of proximal extensions in a tooth preparation?

Extent of caries or previous restoration Signup and view all the answers

What is the recommended height of the shoulder following the lingual or facial axial walls of the cusp in a tooth preparation?

1.5 mm Signup and view all the answers

Why may the fossa areas need to be deeper in a tooth preparation?

To accommodate a deeper depth of the restoration Signup and view all the answers

What is the purpose of blocking out undermined enamel with glass ionomer prior to final preparation and impression?

To prevent further tooth structure loss Signup and view all the answers

What is the recommended width of the isthmus in a tooth preparation?

1.5-2.0 mm Signup and view all the answers

Why is it important to evaluate affected dentin during tooth preparation?

To determine the extent of caries Signup and view all the answers

What is the primary purpose of having a divergent axial wall in an onlay preparation?

To allow for easier placement and removal of the restoration Signup and view all the answers

What type of finish line is recommended for proximal boxes?

A well-defined, smooth butt joint Signup and view all the answers

What is the purpose of providing a rounded internal line and point angles in a tooth preparation?

To facilitate impression making and casting Signup and view all the answers

What is the purpose of temporization after final impression?

To prevent shifting of the teeth and sensitivity Signup and view all the answers

What is the purpose of using a flat-ended diamond in a tooth preparation?

To define internal line angles Signup and view all the answers

What is the recommended method for direct temporization?

Using a light-cured temporary resin material Signup and view all the answers

What is the recommended reduction for a non-functional cusp?

1.5-2.0 mm Signup and view all the answers

What is the purpose of having a butt joint in functional cusps?

To cap the cusp with a shoulder Signup and view all the answers

What is the benefit of having a hollow-ground chamfer?

It allows for better blending of the restoration with tooth structure Signup and view all the answers

What is the purpose of finishing the margins in capping and shoeing?

To follow the contour of the cusp tip and ridges Signup and view all the answers

What should you do if the restoration does not seat easily?

Check for residual provisional material Signup and view all the answers

Why should occlusal contacts be checked after the restoration has been seated?

To prevent restoration fracture Signup and view all the answers

What determines the color of the ceramic restoration?

Shade selection and opacity versus translucency of the ceramic restoration Signup and view all the answers

What is the purpose of the silane coupling agent?

To make the etched ceramic reactive to chemically bond to the composite resin Signup and view all the answers

What is used to link the tooth and restoration interfaces?

Dual cured hybrid resin luting cement Signup and view all the answers

What should be done to the restoration after it is received from the lab?

All of the above Signup and view all the answers

Why is it important to check for marginal integrity?

To ensure the margin is smooth and not catching Signup and view all the answers

What is the purpose of the try-in process?

To try-in the restoration with a light transmitting medium Signup and view all the answers

What is the primary purpose of placing cavosurface margins in a specific location?

To avoid contact with opposing teeth Signup and view all the answers

Why are thin areas of ceramic prone to fracture?

Due to the increased stress concentration in thin areas Signup and view all the answers

What is the minimum recommended width of the isthmus to avoid fracture?

2.0 mm Signup and view all the answers

Why are divergent axial walls recommended for onlay and inlay preparations?

To reduce the risk of fracture Signup and view all the answers

What is the purpose of applying a thin layer of unfilled resin or enamel bonding agent?

To enhance the bond strength between the tooth and restoration Signup and view all the answers

Why is a dual cure capacity composite resin luting agent used for onlay/inlay restorations?

To enhance the bond strength between the tooth and restoration Signup and view all the answers

What is the purpose of 'tacking' the restoration onto the tooth?

To hold the restoration in place during cementation Signup and view all the answers

Why is it necessary to avoid pooling during the application of the luting agent?

To prevent voids in the restoration Signup and view all the answers

Study Notes

Inlay vs. Onlay

Inlay: an intracoronal indirect restoration that does not involve cuspal coverage
Onlay: a partial extracoronal indirect restoration that involves one or more cuspal coverage

Indications for Inlay and Onlay

Inlay: indicated for extensive preparations that require strength greater than a composite or amalgam restoration but do not require cuspal coverage
Onlay: indicated for compromised teeth in high stress areas, and for large restorative defects in low stress areas where esthetics are involved

Advantages of Inlay and Onlay

Improved esthetics
Cover and reinforce cusps without removal of healthy tooth structure
Supragingival margins for easier maintenance

Preparation for Inlay and Onlay

Removal of caries or defect
Initial preparation similar to direct restoration
Cavosurface margins are beveled, including the proximal box
All walls are divergent
Occlusal dovetail is placed if mesial or distal proximal box is not prepared
Secondary flaring of the proximal facial and lingual cavosurfaces joins the gingival bevel uninterrupted

Occlusal Reduction for Onlay

Functional cusps: reduced 1.5 mm
Nonfunctional cusps: reduced 0.75-1.0 mm with minimal extension onto the axial wall
Shoulder following the lingual or facial axial walls of the cusp has a depth of 0.8 mm and occlusogingival height of 2.0-3.0 mm

Conservative Preparation

Remove only compromised tooth structure
Convenience access is provided for the restoration
Affected dentin should be evaluated
Dentin discolored by caries or amalgam may need to be removed or covered by an opaquer

Internal Line Angles and Isthmus Width

Rounded internal line and point angles
Flat ended diamonds work well to define internal line angles
Isthmus width: 1.5-2.0 mm

Pulpal Floor and Proximal Extensions

Pulpal floor can vary according to the planned restored anatomy
Should be 1.5-2.0 mm for adequate bulk for fabrication
Proximal extensions are determined by the extent of caries or previous restoration

Gingival Floor Depth and Cuspal Protection

Gingival floor depth: 1.0-1.5 mm
Should be maintained in enamel whenever possible
Cuspal protection or replacement: extensions of the coverage are a clinical judgment, considering factors such as amount of enamel, occlusal forces, size of functional contact, esthetics, and mesial-distal width of affected area

Cuspal Reduction for Bulk of Restorations

Functional cusp: 2.0-2.5 mm
Nonfunctional cusp: 1.5-2.0 mm

Finish Line and Axial Wall

Finish line should NOT be beveled
Two schools of thought for the finish line:
1. A well-defined, smooth butt joint (shoulder)
2. A hollow-ground chamfer (deep chamfer, or modified butt joint)
Axial wall should be divergent, more than what is required of a gold restoration

Temporization and Cementation

After final impression, the preparation(s) need to be temporized to avoid shifting of the teeth and sensitivity
Indirectly using a preoperative matrix, poured model, temporary fabrication with cementation using a non-eugenol temporary cement
Directly with composite with NO etching or bonding

Try-In and Cementation

Try-in of the restoration with a light transmitting medium like glycerine, water, or try-in paste
Check for proximal contact, marginal integrity, and color
Bonding of the ceramic restoration involves a series of individual links, including tooth interface, restoration interface, and hybrid resin luting cement

Bonding and Cementation

Clean the restoration of any debris
Coat the restoration with a silane coupling agent
Apply a thin layer of unfilled resin or enamel bonding agent
Light cure
Apply composite resin luting agent to the preparation and restoration
Seat the restoration into the preparation, cement should extrude from the margins
Clean off excess cement and floss

Onlay/Inlay Preparation and Cementation

The coupling agent is volatile and allowed to vaporize, leaving a reactive silane on the surface (Crispin, 1994)
A thin layer of unfilled resin or enamel bonding agent is applied to the etched surface of the restoration
The cavity preparation is cleaned using a wet slurry of flour of pumice, soft bristle brush, or micro air abrasion

Luting Agent Application

A thin layer of luting agent is applied to the etched surface of the restoration
The luting agent should be of dual cure capacity due to the thickness and opacity of the onlay/inlay
The restoration is seated into the preparation, and the cement should extrude from the margins

Cementation and Occlusal Reduction

Clean off excess cement and floss to check for any interproximal overhangs
Occlusal reduction should be uniform and of sufficient thickness for ceramic to provide optimal strength
Thickness of ceramic should be at least 1.5 mm in the central fossa and over nonfunctional cusps
Marginal integrity: A sharp explorer should travel from the restoration to tooth structure, and vice versa, smoothly and without catching

Bonding of Ceramic Restoration

Tooth interface: etched enamel micro mechanically bonds with the bonding agent
Restoration interface: The etched porcelain is made reactive by a silane, causing it to mechanically and chemically bond to an unfilled resin layer
Both interfaces are linked together by a dual cured hybrid resin luting cement

Ceramic Restoration Preparation

Cavosurface margins should be placed to avoid contact with opposing teeth
Margins should be smooth and well-defined with no beveling
Thin areas of the ceramic are prone to fracture
Onlay/Inlays rely on adhesion of the resin cement to the dentin and enamel for retention

Preparation Requirements

Prep is nonmechanically retentive
Floors and walls should avoid concavities and divots
All line angles are rounded
Isthmus is at least 2.0 mm to avoid onlay/inlay fracture

Final Thoughts

Occlusal contacts should be checked AFTER the restoration has been seated
Centric and excursive contacts should be checked and adjusted as needed
Bonding of the ceramic restoration involves a series of individual links

Inlays and Onlays

Inlays: intracoronal indirect restorations, not involving cuspal coverage
Onlays: partial extracoronal indirect restorations, involving one or more cuspal coverage

Indications and Contraindications

Inlays: indicated for extensive preparations requiring strength greater than a composite or amalgam restoration, but not requiring cuspal coverage
Onlays: indicated for compromised teeth in high-stress areas, large restorative defects in low-stress areas, and when esthetics are involved

Advantages

Conservative, as only compromised tooth structure is removed
Improved esthetics
Cover and reinforce cusps without removing healthy tooth structure
Supragingival margins, easier for patients to maintain

Preparation

Initial preparation similar to direct restoration
Cavosurface margins are beveled, including the proximal box
All walls are divergent
Occlusal dovetail is placed if mesial or distal proximal box is not prepared
Secondary flaring of the proximal facial and lingual cavosurfaces joins the gingival bevel uninterrupted

Onlay Preparation

Similar to inlay preparation, but with one or more cuspal coverage
Occlusal reduction of nonfunctional cusps is 0.75-1.0 mm with minimal extension onto the axial wall
Functional cusps are reduced 1.5 mm
Shoulder following the lingual or facial axial walls of the cusp has a depth of 0.8 mm and occlusogingival height of 2.0-3.0 mm

Cuspal Reduction

Functional cusps: 2.0-2.5 mm, capped with a butt joint shoulder
Nonfunctional cusps: 1.5-2.0 mm, shoed just beyond the tip and ridge of the cusp
In both capping and shoeing, the margins should follow the contour of the cusp tip and ridges

Finish Line

Two schools of thought: well-defined, smooth butt joint (shoulder) or hollow-ground chamfer (deep chamfer, or modified butt joint)
Axial wall should be divergent, more than what is required of a gold restoration
Increased taper, without unnecessary removal of tooth structure, allows for easier placement and removal when trying the restoration in

Temporization and Cementation

After final impression, the preparation(s) need to be temporized to avoid shifting of the teeth and sensitivity
Indirectly using a preoperative matrix, poured model, temporary fabrication with cementation using a non-eugenol temporary cement
Directly with composite with NO etching or bonding
Light-cured temporary resin material

Try-in and Cementation

Check for residual provisional material, interproximal overhangs, and marginal integrity
Color is dependent on shade selection, opacity versus translucency of the ceramic restoration, and the resin luting cement
Occlusal contacts should be checked AFTER the restoration has been seated
Bonding of the ceramic restoration involves a series of individual links: tooth interface, restoration interface, and a dual-cured hybrid resin luting cement

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.