Porcelain Inlay and Onlay
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Transcript of Porcelain Inlay and Onlay
Porcelain Inlay and Porcelain Inlay and OnlayOnlay
Dr. Ignatius Lee
Preparation and Restoration
Restorative Options - Restorative Options - DirectDirect
1970’s– Posteriors: amalgam
– Anteriors: composite
2000’s– Posteriors: amalgam (material specific), composite (lesion specific)
– Anteriors: composite
Evolution of Cavity Evolution of Cavity Preparation Design for Preparation Design for Posterior CompositePosterior Composite
Taking into consideration the differences in the physical properties between the two materials (amalgam vs composite); and based on the rationale of the cavity preparation design for amalgam
Questions were asked: Do we need convergent walls? retention grooves? Worry about unsupported enamel? Extension for prevention? Do we need bulk?
New cavity preparation design for posterior composite was created; it was based on specific characteristic of the material.
Why are we talking Why are we talking about about
amalgam/compositeamalgam/composite Example of utilizing the skill/knowledge we acquired in using a specific material/procedure (amalgam restoration) and applying it on a new material/procedure (composite restoration)
Preparation skills should be easily transferable.
Knowledge on the rationale of cavity preparation will allow us to adapt to the new material based on the material’s specific characteristic.
Answer to your question on “why are we still teaching cast gold inlay/onlay”? - when only a few dentists are doing these kinds of procedures in their offices.
Restorative Options - Restorative Options - IndirectIndirect
1970’s– Cast gold inlay/onlay, 3/4 crown, full cast crown, PFM
2000’s– Cast gold inlay/onlay, 3/4 crown, full cast crown, PFM
– Porcelain/composite inlay/onlay
Differences between Differences between gold and porcelain gold and porcelain
restorationsrestorations Physical properties - porcelain more brittle
Mode of retention - bonding vs mechanical retention
Concept of margin
Based on these differences, can we design a cavity preparation for using porcelain intra-coronally??
Starting with cavity preparation design for cast gold inlay/onlay, what features do we have to modify for porcelain????
Physical PropertiesPhysical Properties
What cavity preparation features do we need to modify?
– Bulk - more occlusal clearance– Reinforcement - bonding– Bevels contraindicated
Mode of RetentionMode of Retention
Cast gold preparation rely on 6 to 7 degree of divergent walls and sharp internal line angles.
Porcelain rely on the bonding process, no need for 6 to 7 degree divergent wall and sharp internal line anlges.
Marginal AdaptationMarginal Adaptation
Cast gold - rely on close adaptation (20u); lack of adhesion between tooth structure/cement/gold interface
Porcelain - rely on the adhesion between tooth structure/resin cement/procelain to create a gap free continuous margin.
No gingival bevels needed to minimize the gap.
Empress Procelain Empress Procelain SystemSystem
All procelain restoration used for inlay, onlay, full crown
Castable Adequate marginal fit Better wear characteristic than conventional procelain
Similar to cast gold inlay/onlay in terms of cavity preparation design
Porcelain Fused to Porcelain Fused to Metal Crown vs Metal Crown vs
Empress: SimilaritiesEmpress: Similarities
Highly esthetic Wear
Brittle - reinforced through the bonding process
Composite vs Empress: Composite vs Empress: Similarities Similarities
Mode of retention - dentinal bonding agent
Apply skills you learn for composite on the bonding process.
Mechanism of AdhesionMechanism of Adhesion
Porcelain etched with hydrofluoric acid (micromechanical)
Bond between etched tooth and DBA - identical to composite/tooth
Silane coupling agent - chemical bond
Etched Porcelain
Etched Tooth
Silane Coupling agent Dentinal
Bonding Agent
Dentinal Bonding Agent
Resin Adhesive
Summary of Summary of CharacteristicsCharacteristics
Highly esthetic Acceptable marginal fit Conservation of tooth structure
Less occlusal wear Highly technique sensitive
IndicationsIndications High esthetic demand Replace moderate to large existing restoration
Fractured tooth/restoration Moderate to large primary caries
Contraindiations Unable to adequately isolate the field Parafunctional habits - bruxing, clenching, excessive wear
Empress vs Gold Empress vs Gold Inlay/OnlayInlay/Onlay
EmpressEmpressAdvantages ESTHETIC Conservation of tooth structure (gold onlay vs porcelain inlay)
Less complicated cavity design??
Disadvantages Expensive Technique sensitive - bonding process Abrasive to occluding dentition
Empress vs PFMEmpress vs PFMEmpressEmpress
Advantages Conservative cavity preparation Foundation restoration may not be necessary
Less abrasive to occluding dentition No metal collar
Disadvantages Expensive Technique sensitive
Cavity Preparation Cavity Preparation DesignDesign
1. Occlusal Depth/Cusp ReductionOcclusal Depth = 1.5 to 2.0 mmCusp Reduction:Functional cusp = 1.5-2.0mm
Nonfunction cusp = 1.5 mm
2. Internal/External Line AnglesRounded
Cavity Preparation Cavity Preparation DesignDesign
3. DrawDegree of draw = approximately 12 to 15 degree
4. BevelNo bevel
Mn first premolar- DO amalgam with fractured lingual cusp, deep pulpal floor
Existing amalgam removed, making all walls divergent, smoothed all cavosurface margins
Mx first molar - MOD amalgam with deep pulpal floor (4mm)
Existing amalgam removed
Proximal walls and gingival seats extended, occlusal wall divergent, clinical judgement was made to cover DL cusp (with shoulder)
No cavosurface bevel on shoulder
MOB amalgam on Mx first molar with deep pulpal floor
Existing amalgam removed, make all walls divergent and smoothed all cavosurface margins
Occl amalgam on Mn first molar, normal pulpal depth; patient complaining about pain on function- Dx: DB cusp fractured
Patient’s occlusion
Existing amalgam removed, DB cusp reduced by 2mm, all walls divergent
No shoulder on DB cusp - WHY???
MOD amalgam on Mn second molar with fractured Li cusp. Normal pulpal depth; all amaglam removed
Proximal box divergent, Li cusp - smoothed cavosurface margin
MOD amalgam on Mn first molar - occlusal fractured
Shade selection BEFORE rubber dam; need dentin shade (match shade at gingival third) and overall shade
Finished preparation; rubber dam removed; ready for impressioning; proximal box divergent, cusp reduction, buccal cusp with heavy bevel (no shoulder)
Buccal view
Wax up on working cast
Special die for shade matching/staining - reason for taking the dentin shade
Restoration on die/working cast
Trying in under rubber dam; adjust proximal contact; do not adjust occlusal contact
Cementation under rubber dam using resin cement; excess cement removed using cotton tip
Excess resin cement removed from proximal/gingival margins using an explorer
Rubber dam removed following cementation
Adjust occlusion using fine diamond in high speed hand piece
Laboratory Exercise - Mn first molar,
MOD onlay preparation for porcelain
Finished Preparation - MOD porcelain onlay preparation
Restoration on die, back from laboratory
Restoration seated under rubber dam
Bu view after cementation
Restoration on die, back from laboratory
Restoration seated under rubber dam