All-ceramic restorations.pdf

All-ceramic restorations Dr. Sari Aldeek BDS , MDS , PhD candidate in Fixed and Removable Prosthodontics Palestinian Board Assistant Professor in AAUP Rationale behind using all-ceramic restorations.  Esthetic: Transmit light...

All-ceramic restorations Dr. Sari Aldeek BDS , MDS , PhD candidate in Fixed and Removable Prosthodontics Palestinian Board Assistant Professor in AAUP Rationale behind using all-ceramic restorations.  Esthetic: Transmit light similarly to adjacent teeth. Recreate value, Translucency. Control brightness and opacity.  Biocompatibility Ceramics are one of the most biocompatible material with no allergic effect Shortcomings of dental ceramics. 1. Brittleness: weak under tensile forces. 1. Cracks: surface flows act as start point for cracks, alternating mastication forces and presence of water results in growth of these cracks challenges in using all-ceramic crowns. 1. Parafunctional activity. 2. Insufficient support from tooth preparation. 3. Insufficient porcelain thickness in lingual aspect. 4. Opposing teeth that occlude with cervical fifth of the crown. 5. Short clinical crowns. Classification of all-ceramic crowns.  The most commonly used ceramics are classified either according to the laboratory processing procedure or according to their composition.  Classification according to laboratory procedure Fabrication method Examples Condensation Porcelain for PFM ceramics Castable ceramics Dicor Hot pressed or IPS Empress I and II pressable ceramics Slip-casting ceramics In-ceram Alumina, Spinell, Zirconia  Cont….. Fabrication method Examples Computer aided Using Cerec vitablocks machining CAM ceramics CAD/CAM presintered Cercon and Lava ceramics Milling of dry pressed Procera AllCeram powder on enlarged dies  Classification according to chemical composition Chemical composition Examples Feldspathic porcelains Porcelain for PFM Glass ceramics Dicor, IPS Empress I and II, E-max Core reinforced or In-ceram Alumina, Spinell, glass infused Zirconia ceramics Oxide ceramics Procera All-Ceram Composition of all-ceramic crowns  Castable Glass-Ceramics (Dicor) composition 1. Crystallized glasses produced by nucleation and crystal growth in glass matrix. 2. Contains 55% Vol tetrasilicic fluormica crystals. Castable Glass-Ceramics (Dicor) clinical uses Inlay, facial veneer, anterior full crown. Laboratory procedure for Castable Glass-Ceramics (Dicor) 1. The core is formed by lost wax casting. 2. The glass ceramic is then subjected to heat treatment that causes microscopic platelike crystals of crystalline material (mica) to grow within the glass matrix  Dicor use discontinued due to 1. Low tensile strength. 2. Inability to be colored internally.  Hot pressed or pressable ceramics: IPS Empress I& II composition 1. IPS Empress I core contains about 35% vol of leucite crystals. 2. IPS Empress I veneering ceramic contains leucite. 1. IPS Empress II core contains 70% vol Lithia Disilicate crystals in glass matrix 2. IPS Empress II veneering ceramic contains apatite crystals. Hot pressed or pressable ceramics:IPS Empress I& II clinical uses IPS Empress I: limited to fabricate anterior crown. IPS Empress II: used to fabricate three unit anterior bridge up to first premolar  Hot pressed or pressable ceramics: IPS Empress I& II characteristics Excellent translucency and overall aesthetics. Low to moderately high flexure strength and fracture toughness. IPS Empress II has lower translucency than IPS Empress I and higher strength.  Laboratory procedure for Hot pressed or pressable ceramics:IPS Empress I& II 1. A piston is used to force a ceramic ingot through heated tube into a mold, where the ceramic form cools and hardens to shape of mold. 2. Lost wax technique is used to fabricate the core. 3. The veneering porcelain is added either by staining or layering technique. Laboratory procedure for Hot pressed or pressable ceramics: IPS Empress I& II Staining technique Waxing of crown Investing of crown 1. Laboratory procedure for Hot pressed or pressable ceramics: IPS Empress I& II Staining technique IPS Empress ingots Crown after casting with sprue Finished crown  1. Laboratory procedure for Hot pressed or pressable ceramics: IPS Empress I& II Layering technique Waxing of restoration Coping of IPS Empress Crowns after adding dentin layer Crowns after adding transparent and translucent effects  IPS e.max System The IPS e.max system is an innovative all- ceramic system that comprises lithium disilicate (LS2) glass-ceramic and zirconium oxide (ZrO2) materials for the press and CAD/CAM technologies. Types of IPS e.max 1. Material for Press technique: a. IPS e.max Press b. IPS e.max ZirPress 2. Material for CAD/CAM a. IPS e.max CAD b. IPS e.max ZirCAD 3. IPS e.max Ceram for layering: a. IPS e.max Ceram Composition of materials for Press technique: 1. IPS e.max Press: are biocompatible lithium disilicate glass-ceramic ingots. They have flexural strength of (400 MPa). The microstructure of the pressable lithium disilicate (i.e.,Li2Si2O5) material consists of approximately 70% volume of needle-like lithium disilicate crystals that are crystallized in a glassy matrix. These crystals measure approximately 3 μm to 6 μm in length Composition of materials for Press technique: 1. IPS e.max ZirPress: fluorapatite glass-ceramic ingots are used to press onto IPS e.max ZirCAD frameworks  Composition of materials for CAD/CAM technique: 1. IPS e.max CAD: It is composed of lithium disilicate glass-ceramic. The glass-ceramic is processed for the laboratory in a crystalline intermediate phase. In this “soft” state, the material exhibits its unusual “bluish” color and strength of approximately 160 MPa. IPS e.max CAD acquires its final strength of 360 MPa and the desired esthetic characteristics during a simple and quick crystallization process.  Cont… 1. IPS e.max CAD: The IPS e.max CAD “blue block” uses a two-stage crystallization process. The two-stage crystallization uses a controlled double nucleation process where lithium meta- silicate crystals are precipitated during the first step. In a second heat treating step preformed after the milling process, the meta-silicate phase is completely dissolved and the lithium disilicate crystallizes. This process gives the definitive restoration a fine-grain glass ceramic with 70% crystalvolume incorporated a glass matrix. Cont…  Cont… 1. IPS e.max CAD: The glass ceramic in the “blue” stage contains approximately 40 % volume lithium meta-silicate crystals with an approximate crystal size of 0.5 2 μm. In the final stage the glass ceramic contains approximately 70 % volume lithium disilicate crystals with an approximate crystal size of 1.5 μm.  Composition of materials for CAD/CAM technique: 2. IPS e.max ZirCAD : frameworks are either veneered with IPS e.max Ceram or IPS e.max ZirPress is pressed onto them. The specially developed ZirLiner, zirconia liner establishes an optimum bond, no matter which technique you choose. Due to its excellent final strength, IPS e.max ZirCAD is the material of choice for indications where high strength is required, e.g. posterior bridges.  Composition of materials for Layering technique : 2. IPS e.max Ceram : is the connecting element between the different components of the all-ceramic system. Now we only have to use one layering ceramic, which will enable you to achieve highly esthetic results on glass-ceramics as well as zirconium oxide. It is nano-fluorapatite layering ceramic. Indications for several types of e max porcelain IPS e.max Press IPS e.max CAD lithium disilicate lithium disilicate Anterior Crowns X X Posterior Crowns X X Veneers X Thin Veneers X (0.3.mm) Anterior Bridges X Posterior Bridges Inlay X X Onlay X X Implant Restorations X X  Advantages of e max over other types of ceramics: In other types of ceramics the substructure material generally exhibits high value and increased opacity compared to glass-ceramic materials. Second, while the high strength core material has excellent mechanical properties, the layering ceramic with which it is veneered has a much lower flexural strength and fracture toughness. Restorations of this type rely heavily on the ability to achieve a strong bond interface between two dissimilar ceramic materials, oxide ceramic and silica based glass-ceramic. ZrO2 Framework 1000MPa Veneering porcelain 90MPa  Advantages of e max over other types of ceramics: Monolithic glass-ceramic structures offer some distinct advantages in that they provide exceptional esthetics without requiring a veneering ceramic. In many cases, restorations constructed from lithium disilicate materials can be completely fabricated using a monolithic approach. In cases where in-depth color effects are desirable, a partial layering technique may be used. Staining technique Partial layering technique  Slip-casting of core reinforced ceramics: In-Ceram Alumina, Spinell, and Zirconia composition 1. In ceram Alumina core consists of 70% wt Alumina with 30% soduim lanthanum glass. 2. In ceram Spinell core consists of glass infiltrated magnesium spinel. 3. In ceram Zirconia contains 30% wt zirconia and 70% wt Alumina  Slip-casting of core reinforced ceramics: In-Ceram Alumina, Spinell, and Zirconia uses 1. In ceram Alumina is limited for anterior and posterior crowns and anterior three unit FPD. 2. In ceram Spinell is limited for use as anterior inllays, onlays, crowns and veneers. 3. In ceram Zirconia is not recommended for anterior prosthesis, it can be used for posterior crowns and FPD Slip-casting of core reinforced ceramics: In-Ceram Alumina, Spinell, and Zirconia characteristics Comparison between three types of core ceramics Characteristic ICS ICA ICZ Translucency Highest Intermediate Lowest Strength Lowest Intermediate Highest Opacity Lowest Intermediate Highest Laboratory procedure for Slip-casting of core reinforced ceramics: In- Ceram Alumina, Spinell, and Zirconia 1. The core material is applied on porous special die. 2. Heat at 120° C for 2 hours to dry core. 3. Sinter the coping for 10 hours at 1120°C. 4. Apply sodium lanthanum glass slurry mixture on the coping. 5. Fire for 4 hours at 1120°C to allow infiltration glass. 6. Build up dentin and enamel porcelain. 3. Laboratory procedure for Slip-casting of core reinforced ceramics: In-Ceram Alumina, Spinell, and Zirconia Special die for In-ceram Core build up 3. Laboratory procedure for Slip-casting of core reinforced ceramics: In-Ceram Alumina, Spinell, and Zirconia Oxide ceramics: Y-CSZ composaition 1. Pure ZrO2 is not a useful dental ceramic because cracks occur during sintering as a result of phase transformation from tetragonal to monoclinic structure. 2. This transformation was suppressed by adding other oxides as Yttria oxides (Y2O3). 3. Some of this material is presintered and some are supplied as unsintered form.  Oxide ceramics: Y-CSZ method of fabrication 1. Using the CAD/CAM system the preparation is scanned and image is sent to milling machine. 2. If zirconia is sintered the core is milled from the blank, and then veneered. 3. If zirconia is presintered the die is magnified and the core is milled and sintered then veneered.  Oxide ceramics: Procera AllCeram Composition 1. It is composed of densely sintered high purity aluminum oxide core combined with compatible AllCeram veneering porcelain. 2. It contains 99.9% alumina. 3. Its hardness is one of the highest among the ceramics in dentistry.  fabrication 1. Using CAD/CAM system the prepared tooth surface is scanned using Procera scanner and the data is transmitted to milling unit to produce enlarged dies. 2. The core ceramic form is dry pressed onto the die, and the core ceramic is then sintered and veneered  Oxide ceramics: clinical uses Posterior crowns and bridges, implant abutments, and impalnts.  Oxide ceramics: Characteristics 1. High strength. 2. Low translucency. 3. High opacity Clinical procedure: preparation, impression, cementation.  Preparation The role of tooth preparation for all-ceramic crowns to provide support for restoration, with uniform porcelain thickness.  Preparation The length of preparation at incisal lingual aspect provide significant resistance to lingual forces and put restoration under compression.  Preparation The ideal incisal reduction ranges from 2mm to be one third of anatomic crown depending on thickness of incisal edge.  Preparation Shoulder or deep chamfer finish line should be prepared with 1.2mm minimum preparation facially and lingually, and 1.0mm interproximally. Finish line should follow smooth curvature,  Preparation The ideal depth of reduction on the midfacial aspect of a typical maxillary central incisor should be 1.3mm Lingual thickness preparation must be 1.5mm.  Preparation Minimum taper is recommended for maximum surface area and supportof preparation. Convergence angle of all-ceramic preparation is 10°. Preparation Impression  Surface treatment Dicor, IPS Empress I and II: acid etching using hydrofluoric acid. ICS, ICA, ICZ, Oxide ceramics: sandblasted by aluminum oxide particles.  Cementation Why for most of all-ceramic crowns resin cement is preferred: Block crack propagation (strengthen the crowns). Affect the shade of crown due to high translucency of these crowns. Clinical case Preoperative photograph Teeth preparation Retraction cords in place Secondary impression Etching of crowns E max crowns cemented Zircon Crowns Good Luck