Cad cam dentistry/ certificate programs in dentistry


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Indian Dental Academy: will be one of the most relevant and exciting

training center with best faculty and flexible training programs

for dental professionals who wish to advance in their dental

practice,Offers certified courses in Dental

implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic

Dentistry, Periodontics and General Dentistry.

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Cad cam dentistry/ certificate programs in dentistry

  1. 1. INDIAN DENTAL ACADEMY Leader in continuing dental education
  2. 2. INTRODUCTION  The introduction of CAD/CAM systems to restorative dentistry represents a major technological breakthrough.  It is now possible to design and fabricate ceramic restorations at a single appointment, as opposed to the traditional method of making impressions, fabricating a provisional prosthesis and using a laboratory for development of the restoration.
  3. 3.  CAD/CAM generated restorations save the dentist and patient time, provide an esthetic restoration, and have the potential for extended wear resistance.
  4. 4. EVOLUTION OF THE CAD/CAM SYSTEMS  Optical scanning and computer generation of restorations were attempted as early as 1971 (Altschuler, 1971/1973).  With the continued improvement in the technology, a number of systems were currently being investigated at this time (Duret et al,1988;Williams,1987; Rekow,1987; Brandestini et al,1985; Duret and Preston,1991).
  5. 5.  The teams most actively pursuing this technology of CAD/CAM in dentistry were the French group, headed by Dr. Francois Duret, whose system is currently being investigated at the University of Southern California;  The DentiCAD unit at the university of Maryland, led by Dr Dianne Rekow;  And the Brandestini / Mormann unit,Working on the CEREC System.
  6. 6.  This French System - one of the earliest - was first shown as a prototype in 1983.  This System uses lasers to optically scan the image or preparation in the patient's mouth.  Multiple images from different angles are obtained with an optical probe.The Computer then creates a three dimensional composite view of the tooth on which the operator can trace the margins of the preparation.
  7. 7.  This system is capable of milling inlays, full crowns, and three – unit fixed partial dentures.  With this system dentists would most likely have to maintain the probe in the dental office and transmit data to a central laboratory for prosthesis fabrication.
  8. 8.  Dr Dianne Rekow originally used a technique described as being "Stereo photogrametric".  It used a series of black and white photographs to create the tooth contours necessary to rebuild missing parts of the clinical crown.  The information was converted to digital form, which was used by a computer to reconstruct the crown.
  9. 9.  The third system, the CEREC system, developed in Zurich, Switzerland,can fabricate onlays, ¾ Crowns, 7/8 crowns, and veneers.  This system allow the clinician to restore the tooth with an indirect, permanent restoration in one appointment.This is done without the use of an impression or the assistance of a laboratory technician.
  10. 10.  It consists of three basic components: a small camera, a computer with screen and three axis of rotation milling machine.  A new version of the milling motor has been introduced. It uses an electric motor ("E" version) to drive the milling wheel instead of the water-pressure-driven "hydro" version.  This provides a smoother cutting of the ceramic, hence a better fitting restoration.
  11. 11. MATERIALS USED FOR CAD/CAM RESTORATIONS:  Chair side Materials  Laboratory based materials Materials fabricated for use in CAD/CAM systems must be able to be milled rapidly, resist machining damage and be finished easily before placement.
  12. 12. CHAIR SIDE MATERIALS  CEREC 3 (Sirona Dental Systems, Germany) is the only chair side system available. Materials available for use with CEREC3 include: a.feldspathic porcelain-based ceramics Vitablocs Mark II (Vita Zahnfabrik,Germany) ProCAD (lvoclar Vivadent, Lichtenstein) & b.Resin-based composite block: Paradigm MZIOO (3M ESPE)
  13. 13. Vitablocs mark II:  This contains sanidine (KAISi3O8) as a major crystalline phase within a glassy matrix.  They are fabricated using fine-grained powders that produce a nearly pore-free ceramic with fine crystals.This results in improved polish ability, decreased enamel wear and increased strength.
  14. 14.  Strength of this material is approximately 130 Mpa when polished & about 160 Mpa or higher when glazed, which is about twice as strong as conventional feldspathic porcelains.  The material has excellent esthetic qualities and can be characterized using external stains and a porcelain add-on kit.
  15. 15. ProCAD blocks:  ProCAD blocks have a fine leucite crystal structure (about 5 to 10 micrometers in size) and can be further characterized using external stains.  Strength properties are similar to those ofVitablocs Mark II blocks.
  16. 16. Paradigm MZ1OO:  This is a resin-based composite with micro zirconia-silica fillers.  Its block form has mechanical properties superior to those of the conventional Restorative direct resin-based composite.
  17. 17.  All of these blocks have a fine particle-sized microstructure that helps resist machining damage, improve mechanical properties, decrease polishing time and improve wear kindness of the finished restoration.  They are mono chromatic. A variety of block shades are available to match the patient's natural dentition and these materials exhibit a "chameleon" effect in that they tend to blend in with the surrounding tooth structure.
  18. 18. LABORATORY-BASED MATERIALS Several materials are available: a) Vita In-Ceram (Vita Zahnfabrik) b) IPS e.max CAD (IvoclarVivadent) c) Yttria partially stabilized zirconia materials (so called "pure" zirconia) >Vita InVizion system(Vita In-CeramYZ) > IPS e.max ZirCAD (IvoclarVivadent)
  19. 19. Vita In-Ceram Materials:  They belong to a class known as "interpenetrating phase composites".  They involve at least two phases that are intertwined and extend continuously throughout the material.  Porous blocks of Vita In-Ceram materials are milled to produce a frame work.Then the blocks are infused with a glass in different shades to produce a 100% dense material which then is veneered with porcelain.
  20. 20. Vita In-Ceram is available in 3 types:  Vita In-Ceram Spinell  Vita In-Ceram Alumina  Vita In-Ceram Zirconia  Vita In-Ceram Spinell is the most translucent with moderately high strength (350 Mpa) for anterior crowns.  Vita In-Ceram Alumina with high strength (450-600Mpa) and moderate translucency for anterior and posterior crowns.  Vita In-Ceram Zirconia with high strength (700Mpa) and lower translucency for anterior and posterior crowns.
  21. 21. IPS e.max CAD:  This is a lithium disilicate glass ceramic similar to IPS Empress 2 (IvocIar Vivadent) in strength (320Mpa) and microstructure.  In block form it is only partially crystallized to facilitate machining. After milling the framework is fired at 850 C for 0.5 hour, which completes the crystallization.  This may be used for crowns, inlays and onlays.
  22. 22. Partially Stabilized Zirconia Materials:  It is reliable material for high-stress areas, such as posterior region of the mouth.  Owing to its high strength and toughness, zirconia is a universal ceramic restorative material that can be used any where in the mouth.
  23. 23.  Zirconia may exist in several crystal types depending upon the addition of minor components such as calcia, magnesia, yttria or ceria.  Specific phases are said to be stabilized at room temperature by the minor components. If about 8-12%of a component is added, a fully stabilized cubic phase, such as cubic zirconia is produced.  If smaller amounts (3-5% weight ) are added, then a partially stabilized tetragonal zirconia phase is produced.
  24. 24.  Under stress, the phase may change to monoclinic phase, with a subsequent 3% volumetric size increase.  This dimensional change takes energy away from the crack and can stop its growth and is called "transformation toughening".  Natural teeth often contain many cracks in the enamel that do not propagate through the entire tooth.These cracks can be stopped by the unique interface at the enamel-dentin junction.
  25. 25.  The ability to stop the cracks as they enter the zirconia core structure mimics the effect seen in natural teeth.  Transformation toughening helps give the zirconia its excellent mechanical properties: high flexural strength (1.0 giga pascals) and toughness.  Another beneficial property is its good biocompatibility.
  26. 26.  The Vita In-CeramYZ and IPS e.max ZirCAD blocks are partially fired to produce a chalky block that is milled easily.  The framework is milled oversized to account for firing shrinkage of 20-30 % and fired at about 1,500 C to fully densify the zirconia.  Each block has a bar code that tells the computer the density at which to properly mill the framework oversized.  Systems such as Lava (3M ESPE), Cercon Zirconia (Dentsply), and Everest (KaV0 Dental) use this approach.
  28. 28. 1. CEREC SYSTEM: (Computer-assisted CERamic REConstruction)  Dr.Brandestini produced the first design for the CEREC 1 unit and intra oral camera.  The CEREC 2 and 3 units, as well as the CEREC inLab , and extraoral scanner and the associated software versions, were developed by CEREC teams at Siemens and Sirona (Bensheim, Germany).
  29. 29. Cerec 1- 1985……first chair side inlay Cerec 2- 1994…..partial & full crowns Cerec 3- 2000….three unit bridge 2003….four unit bridge 2005….automatic occlusal adjustments..
  30. 30. Clinical Procedure for the CEREC System: Preparation Design:  There are certain prerequisites for the preparation design for a CEREC restoration.The conventional inlay design must be modified to best use the capabilities of the milling device.  The computer cannot accurately read bevels, convexities, steps or undefined angles; it is therefore imperative that the prepared walls be as straight as possible.The ideal occlusal wall can be vertical, slightly convergent, or slightly divergent to the occlusal cavosurface.
  31. 31.  If an undercut portion is generated during the preparation procedure, it will be blocked out during imaging and become filled in with the luting composite resin.  The occlusal cavosurface should have a smooth, flowing outline.
  32. 32.  Floors and walls that are relatively flat give the computer an image that is more discernible and allow a much more intimate fit, especially at the margin.  Irregular surfaces make it more difficult for the milling machine to accurately mill the ceramic material.
  33. 33. The Optical Impression:  The surface of the prepared tooth often lack sufficient reflectivity. It is therefore necessary to coat the preparation with a special powder that has the proper light reflective ability.  A hand-held camera is placed over the prepared, powder- coated cavity to obtain a fixed image on the computer screen.The camera is adjusted until a clear image and all aspects of the cavity can be seen.
  34. 34.  It is essential to position the camera over the long axis so that the computer can read all internal walls and cavosurfaces equally.  At this point, the operator, by releasing the foot pedal, "freeze frames" the preparation on the screen.  The focal length of the camera is 10 mm; any depth greater than 10 mm will not focus properly and an ill- fitting restoration subsequently will be generated.
  35. 35. Computer-Generated Restoration Design:  The restoration is designed from the image shown on the computer screen by using a series of icons or symbols.  The operator can electronically design the restoration by moving a cursor along the limits of the preparation, thereby defining its boundaries.
  36. 36.  The procedure can be stopped at any time and edited to override the computer and allow the operator to correct the electronically generated features.  Once the restoration has been designed, the computer develops the on screen 3-dimensional model or image of the inlay, onlay or veneer.
  37. 37.  All of the information generated is stored automatically on a programmed floppy disk. Up to 3 images may be stored on each disk.  The design phase usually takes from 2 to 8 minutes.This is even possible when designing multiple cusp replacements or veneers.
  38. 38. Milling Procedure:  After all the data have been supplied, the computer selects the size & shade of ceramic block to be used in the milling process.  Three materials can be used with this system: Vita MarkII DicorMGC ProCad
  39. 39.  The material is mounted on a metal stub, which allows it to be inserted into the milling unit. Once the material is inserted, the small window is closed and the milling device is activated.  The milling is accomplished by a three-axis-of rotation cutting machine, which mills 25 micro mm slices.
  40. 40.  A diamond wheel is driven by the electric motor, which generally takes 4 to 7 minutes to complete the procedure.  The milling allows for occlusal contours of the cuspal inclines, marginal ridges and proximal contours.  It does not provide for internal and secondary occlusal anatomy. This is developed by the operator intraorally after the inlay has been cemented.
  41. 41. Clinical Placement:  Because breakdown primarily occurs at the tooth- restoration interface, the interfacial gap and luting agent play an important role in longevity of the restoration.  The gap should be kept under 100microns, particularly on the occlusal surface.
  42. 42.  Cementation involves etching the tooth with a 37% solution of phosphoric acid for 20 seconds.  The tooth is then washed and dried and a bonding agent is applied.  The ceramic restoration is etched on its undersurface, outside the mouth.
  43. 43.  Currently, the two materials of choice are the Dicor ceramic material andVita porcelain.  The Dicor is etched with ammonium bifluoride, and the Vita is etched with a buffered hydrofluoric acid gel.  With either material, a silane coupling agent must be applied to the undersurface for better retention to the composite resin luting agent.
  44. 44.  A dual-cure microfill composite resin luting agent is used to bond the inlay, onlay or veneer.  The Brasseler system of diamonds is excellent to make the final finishing and polishing using diamonds, 12 and 30 bladed carbide burs, rubber points and diamond paste.
  45. 45. Advantages of the CEREC System:  Single appointment  No impression  Bonded restoration for strength  Reduced marginal gap  Wear hardness similar to enamel  Less fracture of the inlay, because it is milled from a solid, homogeneous block
  46. 46.  Excellent polishing characteristics  Improved esthetics  Less reduction of tooth structure, hence better periodontal health  Bonded restorations enhance tooth strength  Preparation, fabrication, cementation and polishing normally accomplished in 1 to 1.5 hours.
  47. 47. 2. THE CELAY SYSTEM:  It was developed by Dr. Stefan I.Eidenbenz at the University of Zurich, is a variation on the direct-indirect restoration concept but without the need for a laboratory technician.  An inlay or onlay preparation is made for the compromised tooth, but, instead of a conventional impression, a direct process is used.
  48. 48.  A moldable precision imprint material is molded directly inside the mouth in the cavity preparation, where it is adjusted for occlusion, contact relations, and marginal integrity.  The material then undergoes a light hardening or curing process before it is removed from the tooth to serve as a prototype model to be copied and reproduced in ceramic on a unique milling system developed by Claude Nowak of MicronaTechnology,Germany.
  49. 49. Design of Milling Machine: The milling center has two distinct aspects:  In one half the model to be copied is centered in a holder, where it is manually scanned.  A second part of the Milling machine contains a rotary turbine with various cutting tools.
  50. 50.  The resin pattern (pre-inlay) is held for overall surface tracing in a dry chamber on the left side of the unit.  A ceramic blank is machined using a high speed turbine in the wet carving chamber on the right side.  A pantographic arm is situated between two stations and acts as a geometric transfer mechanism to link the 3- dimensional movements of the tracing device along the eight axes provided with the milling device.
  51. 51. Pre-Inlay Fabrication: a. Direct Method:  Control of marginal excess and carving occlusal surfaces is difficult because of the lack of color contrast with the natural tooth.  Also, light-activated pattern materials set rapidly, and their rigidity makes removal difficult.
  52. 52.  A three-component composite material (ESPE-CELAY Dent, Germany) is developed to achieve a more "elastic" setting characteristic that can be hardened later using a blue light.  A dead soft steel matrix band with the necessary plasticity can be used to facilitate proximal contouring.
  53. 53. b. Indirect Method:  A light-activated composite material is chosen for modeling on the die where undercuts can be more easily recognized and eliminated.  Longer working time allows the technician to form natural occlusal surfaces for more complex restorations.  This material also is colored with dark blue pigments but with less light activator to delay setting and provide more manipulation time.
  54. 54. Clinical Procedure:  Tooth preparation follows the accepted rules for adhesive inlay restorations.  The cavity is cleaned and a steel matrix band is secured using proximal wedging. A thin coat of a separating medium is applied to the prepared tooth structure.
  55. 55.  The three component resin is adapted to the cavity walls using finger pressure and a ball gauge.  A special composite spatula (CELAY spatula, ESPE) is used for final forming.  Occlusal contacts are checked during maximum inter cuspation as well as during excursive movements.
  56. 56.  While the material is still elastic after the initial setting, a manipulative device(Visioform,Espe)is luted to the surface pattern to facilitate removal and left attached until after final polymerization using the blue light.  When using the indirect procedure, an elastomeric impression of inlay preparations is needed to fabricate working cast.The stone die is prepared.
  57. 57.  After the material has been adapted, the die is replaced into the mounted working cast to adjust proximal and occlusal contacts.  After all contact areas have been adjusted, the pattern is light activated.
  58. 58. Milling Procedure: Pattern is mounted on a jig in the left side of the unit. The following milling instruments and polishing instruments are used:  A coarse diamond disk with a grit size of 126 microns for efficient bulk reduction.  A finishing diamond disk with a grit size of 64 microns for precision milling of the final contour.  Round tip diamonds with a grit size of 64 microns for narrow concavities, i.e., secondary occlusal anatomy.
  59. 59. Procedure:  For economy, the smallest ceramic blank possible(Vita- CELAY Blank) is mounted.  To reduce overall carving time, the bulk of excess ceramic material is trimmed with the coarse diamond disk to a rough estimate of the desired restoration.
  60. 60.  A highly filled, hybrid, dual-activated luting composite resin agent has been used for cementation of direct as well as indirect inlays.
  61. 61. Advantages of the CELAY System:  A precisely fitting ceramic restoration can be developed in one patient session.  A ceramic restoration can be developed without the need for a laboratory technician.
  62. 62.  The restoration is developed in factory-fired high grade porcelain.  The processing time required is very short.  A small inlay can be milled in 3 minutes, a mesio occluso distal inlay in less than 8 minutes, and a complete onlay in 12 to 13 minutes.
  63. 63. 3. PROCERA ALLCERAM SYSTEM:  It involves an industrial CAD/CAM process.  The die is mechanically scanned by the technician, and the data are sent to a work station where an enlarged die is milled using a computer-controlled milling machine.
  64. 64.  This enlargement is necessary to compensate for the sintering shrinkage.  Aluminium oxide powder is then compacted onto the die, and the coping is milled before sintering at very high temperature (>1550C).  The coping is further veneered with an aluminous ceramic with matched thermal expansion.
  65. 65. Step by Step Procedure:  Tooth preparation follows all ceramic guide lines.  The cast is made in the conventional way but the die is ditched to make the margin easier to identify during scanning.  The die is mapped using a contact scanner.
  66. 66.  The shape of the prepared tooth is transferred to the computer screen.  The design of the restoration is transferred to the manufacturer via computer line.  The production process starts with milling and enlarged die to compensate for the sintering shrinkage.  An enlarged high-alumina coping is milled that shrinks to the desired shape after sintering.
  67. 67.  The coping is returned to the laboratory, and body and incisal porcelains are applied in the conventional manner.
  68. 68. NOBEL PROCERA  Can be used on any anterior or posterior teeth, implants or abutments.  Best precision fit. Production accuracy of < 10 microns.  Highly biocompatible & homogeneity.  Materials used are zirconia (1120 MPa), alumina ( 600- 700MPa),Titanium ( 345- 860 Mpa)
  69. 69. Advantages: a) Industrial fabrication. b) High quality product & long term success. c) Veneering thickness is uniform to prevent chipping. d) Eliminates time consuming adjustments. e) Broad prosthetic versality. f) Tooth preparation & cementation is same as conventional.
  70. 70.  Excellent esthetics  Excellent flexural strength.  Excellent material homogeneity.  Innovative coloring technique.  Automatic cut back function.  Customized trans mucosal profile.
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  78. 78. 4. COMET SYSTEM: (COordinate MEasuring Technique)  The COMET system allows the generation of a 3- dimensional data record for each super structure, with or without the use of a wax pattern.  Optical, full surface, high speed digitization allows for wax patterns of the final restoration to be recorded with speed and precision.
  79. 79.  The COMET system uses a pattern digitization and surface feedback technique, which accelerates and simplifies the 3-dimensional representation of tooth shapes while allowing individual customization and correction in the visualized monitor image before milling.  The final restoration is then milled or ground from any desired material by an associated milling unit.
  80. 80. Three steps are involved: a) Digitizing data from the die surface or a wax pattern surface. b) Mathematical processing of data to program the milling machine, and c) Milling of copings, crowns, multiunit restorations, and implant abutments.
  81. 81. Three procedural options are currently feasible: 1.  An impression is obtained of the prepared tooth, master cast poured in die stone.The planned restoration is then waxed and the surface of the completed wax pattern opto- electronically scanned and digitized.  After removing the wax pattern from the die, the surfaces of the prepared tooth in the cast are digitized as well.  The individual views are linked by special software.  Thus, single crowns) inlays and onlays can be made of various metals or metal alloys, ceramics or resin materials.
  82. 82. 2.  The prepared tooth surface and contact and occlusal surfaces of the adjacent and opposing teeth on the master model are digitized.  A CAD program is used to generate the new crown surface; whereas, the crown interior is computed from the prepared tooth surface data.
  83. 83. 3.  For the production of custom copings, it is sufficient to digitize the prepared tooth on the master cast.  External and internal surfaces of the copings are computed by the software.
  84. 84. Digitizing:  The COMET system is characterized by an optical sensor that is capable of capturing between 400,000 and 1 million data points simultaneously, depending on the resolution of the camera used.  Automatic measurement software determines how many views must be taken to reconstruct the object exactly.The various views are then linked together in the computer to form the tooth or prepared surface.
  85. 85. Data Processing:  The surface of an object to be measured consists of a number of points.  Because only a finite number of points can be digitized opto- electronically, a feature of the software computes the non digitized points and generates a 3-dimensional image of the surface of the object to be measured.
  86. 86.  To make single crowns, an additional program is available for customization of occlusal surfaces whenever it is useful to do so without a wax pattern.  For manufacturing copings, the prepared tooth surface is digitized, computed and shown on the monitor. Coping dimensions are then calculated and the finish line is verified.
  87. 87. Milling:  This milling machine, especially developed for dental applications, is equipped with a multiple-axis, high speed milling/drilling tool, with interchangeable cutters driven by computerized velocity and rotating at a maximum speed of 60,000 rpm. It takes place in4 steps:  Rough milling of outside surfaces for bulk material removal
  88. 88.  Fine outside milling to finalize the outer contours and surfaces of the restoration.  After rotating the work piece by 180 degrees, rough internal milling.  Fine inside milling to produce accurate internal fitting surfaces of restoration.
  89. 89. 5. CICERO SYSTEM: (Computer Integrated Ceramic RecOnstruction)  described by Denisson.  It uses optical scanning, ceramic sintering, and computer- assisted milling techniques to fabricate restorations with maximum static and dynamic occlusal contact relations.  With the CICERO CAD/CAM method, crowns and inlays with different ceramic layers-such as high-alumina core, dentinal, and incisal porcelain for maximal strength and enhanced esthetics are produced.
  90. 90. PROCEDURE: 1. Scan-model preparation:  An impression is made of the arch with the prepared teeth and poured in gypsum.  The gypsum cast of the model that contains the preparation is marked with black/white contrast for unambiguous scanning of the margin.
  91. 91. Optical scanning:  The first step is an optical impression obtained by laser scanning of the cast.  CICERO CAD/CAM system makes use of a fast laser-stripe scanning method to measure the 3-dimensional geometry of the preparation, its immediate surroundings, and the opposing teeth.  A straight laser stripe, which is projected onto the cast, is deformed by the 3-dimensional occlusal geometry of the tissues; this deformation is used by the computer to determine the actual 3-dimensional positions of those points on the surface of the tissues.  Camera scans the projected line.
  92. 92. Design:  The crown form is designed by selecting the proper tooth element from the library, modeling the crown on the screen to fit, with the remaining dentition, and making final adjustments to the proximal contacts with the computer.
  93. 93.  The appropriate tooth is chosen by the operator from an extensive collection of generic forms of theoretical teeth in the program's library.  When an intact mirror element can be found in the arch, it can be scanned and used as a standard tooth.
  94. 94.  The lingual and buccal boundaries are clicked in and dragged with the mouse to shape the tooth so that it fits in a natural-appearing row with the adjacent teeth.  Thus, the external contours of the new crown can be adjusted interactively with the mouse, in much the same way that porcelain is built up by brush.
  95. 95.  After the crown has been fitted into the row, the computer adjusts the mesial and distal contacts to within +-0.02mm of the adjacent teeth.
  96. 96. Design of crown layer buildup:  After the interior and exterior tooth surfaces have been designed, several interface surfaces between cement and ceramic core and between dentin and incisal porcelain are defined.  The CICERO software calculates the interior surface corrected with marginal gap (0.03 mm), overall cement thickness (0.05-0.1 mm), and ceramic core-die cement thickness (0.02mm) as specified by the operator.
  97. 97.
  98. 98. 6. OTHER CAD/CAM SYSTEMS: 1. DCS Precident  It is consists of a Precision laser scanner and Precimill CAM multi tool milling center.The DCS Dentform software automatically suggests connector sizes and pontic forms for bridges.  It can scan 14 dies simultaneously and mill up to 30 framework units in 1 fully automated operation.
  99. 99.  Materials used with DCS include porcelain, glass ceramic, In-Ceram, dense zirconia, metals, and fiber-reinforced composites.  This system is one of the few CAD/CAM systems that can mill titanium and fully dense sintered zirconia.
  100. 100. 2. Lava:  Introduced in 2002, it uses a laser optical system to digitize information from multiple abutment margins and the edentulous ridge.  The Lava CAD software automatically finds the margin and suggests a pontic.  The framework is designed to be 20% larger to compensate for sintering shrinkage.
  101. 101.  After the design is complete, a properly sized semi sintered zirconia block is selected for milling.  The block is bar coded to register the special design of the block.
  102. 102.  The computer controlled precision milling unit can mill out 21 copings or bridge frameworks without supervision or manual intervention.  Milled frameworks then undergo sintering to attain their final dimensions, density, and strength.  The system also has 8 different shades to color the framework for maximum esthetics.
  103. 103. 3. Everest:  Marketed in 2002, it consists of scan, engine, and therm components.  In the scanning unit, a reflection-free gypsum cast is fixed to the turntable and scanned by a CCD camera in a 1:1 ratio with an accuracy of measurement of 20 microns.
  104. 104.  A digital 3D model is generated by computing 15 point photographs.  The restoration is then designed on the virtual 3D model withWindows-based software.
  105. 105.  Its machining unit has 5-axis movement that is capable of producing detailed morphology and precise margins from a variety of materials including leucite-reinforced glass ceramics, partially and fully sintered zirconia, and titanium.  Partially sintered zirconia frameworks require additional heat processing in its furnace.
  106. 106. 4. Cercon  The Cercon System is commonly referred to as a CAM system because it does not have a CAD component. In this system, a wax pattern (coping and pontic) with a minimum thickness of 0.4 mm is made.
  107. 107.  The system scans the wax pattern and mills a zirconia bridge coping from presintered zirconia blanks.  The coping is then sintered in the Cercon heat furnace (1,350C) for 6 to 8 hours.
  108. 108. CLINICAL PERFORMANCE OF CHAIRSIDE CAD/CAM RESTORATIONS:  CEREC 3 is the only chair side system available.  Since the CEREC-generated restorations are placed in a single appointment, some postoperative sensitivity will be the result of occlusal interferences.
  109. 109.  Restoration Fracture: Insufficient porcelain thickness is one of the major contributors to the fracture of porcelain restorations.  Color Match: A custom stain and glaze technique can be used to modify the color of a porcelain restoration to ensure an esthetic match to a natural tooth.
  110. 110.  Margin Adaptation: It is expected that well-fitting margins will maximize the longevity of restoration. Resin-based composite cement wear at the margin leading to ditching has been reported in almost all clinical evaluations of CEREC-generated inlays. The margin wear is a surface phenomenon and is not accompanied by a breakdown in the adhesive bond to the tooth.
  111. 111.  Clinical Longevity: Ceramic fracture was the overwhelming primary reason for failure, followed by supporting tooth fracture. Ceramic fracture is thought to be a result of occlusal stress or insufficient ceramic thickness.
  112. 112. CONCLUSION We feel proud that we have been using dental restorative and prosthetic devices to recover and maintain the oral function and health of patients. There is no doubt that the application of CAD/CAM technology in dentistry provides innovative, state-of-the- art dental service, and contributes to the health and QOL of people in aging societies. Therefore, we in the field of dentistry must not procrastinate in implementing new technology for the benefit of our patients.
  113. 113. Thank you For more details please visit