Anterior Full Coverage Crowns Flashcards
Indications for anterior full coverage crowns?
Aesthetics Broken down anteriors Toothwear Trauma Atypical shape and hypoplastic conditions Milled crowns and attachment for dentures Retainers for cantilever bridgework To alter occlusion
Contraindications of anterior full coverage crowns?
More conservative options available
Poor OH
V broken down tooth with caries extending subgingivally
Periodontal condition - not enough bone support
Types of anterior crowns?
Metal ceramic All porcelain - Porcelain jacket crown - Dentine bonded crown - High strength porcelain - CAD CAM
Features of metal ceramic crowns?
Most popular porcelain crowns Metal core and ceramic veneer Heavy labial prep (1.5mm) Lighter palatal prep (0.7mm) Less aesthetic due to metal substructure Option for metal backings Good for bruxism cases
Features of all porcelain crowns: porcelain jacket crown?
Oldest type
V brittle before cementation
Not v strong type of all ceramic crown
Features of all porcelain crowns: Dentine bonded crowns?
Use thin layer of glass ceramics relying on bonding to underlying tooth structure for strength
Light chamfer margin conservative preparation (0.7mm)
Ideal for minimally restored teeth requiring crowns for aesthetic reasons
Features of all porcelain crowns: Pressed ceramics?
Strong core or full contour crown is produced by pressing ceramic material at high temp on a die
e.g. Empress I, II
Features of all porcelain crowns: Castable ceramics?
Dicor system
Wax pattern of crown was made, invested in a spacial investment and casted in a glass ceramic material
Casting then placed in a ceramic oven and left for several hours
Crystalisation process was taking place giving a stronger core
Core is veneered with feldspathic porcelain to achieve good aesthetics
Features of all porcelain crowns: Glass infiltrated high strength ceramic core systems?
In-ceram
An alumina core is formed using slip casting
This core is porous and is then infiltrated with glass
A dense core is produced
In-ceram spinel, in-ceram zirconia
Features of all porcelain crowns: high strength core ceramics?
Pure alumina
Pure zirconia
Features of all porcelain crowns: CAD CAM?
Crown is milled from a single block of porcelain e.g. cerec
Chairside CAD/CAM available
Reduce human error
Standardised restoration shaping processes
Produce higher and more uniform quality material by using commercially formed blocks of material
Use of materials that otherwise would be difficult to use e.g. zirconia, titanium
All porcelain crown features?
Increasing in popularity
More conservative labial prep, but more destructive palatally (1.2mm rounded shoulder)
More aesthetic due to absence of metal substructure and no metal showing at margin
Some can be bonded to underlying tooth but some cannot as the highest strength porcelain is not etchable
Shoulder must be rounded with no sharp angles
Indications for dentine bonded crowns?
Minimally restored tooth
Aesthetic paramount
Suitable occlusion
Indications for high strength porcelain?
More heavily restored tooth
Aesthetics important
Indications for metal-ceramic crowns?
More heavily restored tooth
Heavier occlusion (bruxism)
Aesthetics less essential
