1. CAD-CAM IN FPD

3. TECHNOLOGICAL TRENDS IN DENTISTRY
Information systems Treatment systems

4. INTRAORAL IMAGING SYSTEM

5. COMPUTER IMAGING SYSTEM

6. CAD-CAM SYSTEM

7. DIGITAL RADIOGRAPHIC SYSTEM

8. COMPUTERIZED PERIODONTAL PROBE

9. RADIOGRAPHIC IMAGE PROCESSING SYSTEM

10. TREATMENT SYSTEMS
Abrasive system
Laser system

11. CAD-CAM SYSTEM
Acronym for computer aided designing and computer aided milling or machining.

12. BRIEF HISTORY Increasing demand Restoration at a single appointment
Development- began in 1970’s with Duret in France.
French system - in 1983 by Dr.Francois Duret

13. Mormann 1985 in Zurich, Switzerland
On September 19, 1985, the first ceramic inlay was produced- at the dental Institute of the University of Zurich.
Mormann 1985 in Zurich, Switzerland

16. FUNDAMENTAL PRINCIPLES OF CAD/CAM SYSTEM
CSD
CAD
CAM

17. ADVANTAGES One visit restoration Time saving Improved esthetics
Good morphology
Improved crown fit

18. Less fracture due to single homogenous block
Excellent polish
Less fracture due to single homogenous block
Wear hardness similar to enamel (Craig 1980)
Minimize cross infection
Good patient acceptance

19. DISADVANTAGES Need for costly equipment Need for extended training
Technique sensitive
Inability to image in a wet environment

20. MACHINABLE CERAMIC MATERIALS
Dicor MGC
Vita Mark II
Inceram Alumina
Inceram Spinell
Inceram Zirconia
Pro-Cad
Procera Allceram

21. MACHINABLE CERAMIC FRACTURAL STRENGTH
Dicor MGC
229MPa
Vita Mark II
122MPa
Inceram Alumina
500MPa
Inceram Zirconia
700MPa
Inceram Spinell
350MPa

22. CERAMIC BLOCKS Available in wide range of shades and sizes
More homogenous
Less porous
Mounted on a metal stub

23. Effects of surface finish and fatigue testing on the fracture strength of CAD-CAM and pressed – ceramic crown (Hickel - JPD 1999)
Purpose
To determine the fracture strength of various all ceramic crowns with and without cyclic loading.

24. Material & Method
Machinable ceramic material, Vita Mark II and ProCAD and conventional heat-pressed IPS – Empress crowns were fabricated, with either a polished or an oven – glazed surface finish.
Cyclic loading that simulated oral conditions were performed on half of each group.

25. Conclusion
The Cerec Pro-CAD crowns had significantly greater strength than the Vita Mark II crowns, better resistance to cyclic loading and lower failure probability than laboratory fabricated IPS empress crowns.

26. Cyclic loading significantly reduced the strength of all-ceramic crowns, but had less effect on cerec crowns than on the IPS Empress crowns.
Oven-glazing of ProCAD crowns resulted in significantly higher strength and higher resistance to cyclic loading than surface polishing.

27. An upto 5 year Clinical Evaluation of posterior In-ceram CAD/CAM core crowns (Mormann – Int. J Prosthodont 2002)
Evaluated the clinical performance of posterior CAD-CAM generated In-ceram alumina and In-ceram spinelll core crowns using the corec 2 CAD-CAM system and after 5 years of service concluded that the clinical quality of CAD-CAM generated In-ceram Alumina and In-ceram Spinell posterior crowns was excellent

28. Computer generated restoration design Polishing and cementation
CLINICAL PROCEDURE
Preparation Design
Optical Impression
Computer generated restoration design
Milling
Polishing and cementation    

29. PREPARATION DESIGN

30. OPTICAL IMPRESSION Lacks reflectivity Special Powder Rubber dam

32. COMPUTER GENERATED RESTORATION DESIGN
Restoration is designed
Operator moves the cursor
3-D image
Design phase – 2 – 8 min.

33. MILLING Computer selects Block is inserted Milling device is activated
Three axis of rotation cutting machine

35. PROCESSING TIME Process Step Coping Bridge framework Scanning
Approx. 10min
Approx. 20min
Designing
Approx. 2 min
Approx. 6 min
Milling
Approx. 15min
Approx. 50min

36. POLISHING Rough ceramic surfaces are smoothed with clean white stones
Polished with
- Rubber wheel of fine grit
- Diamond impregnated wheels & points

37. CEMENTATION Composite resin cement Zinc phosphate Glass ionomer
Ceramic restoration that have been etched internally and bonded with a composite resin cement are 50% stronger than similar restoration cemented with zinc phosphate cement (Ludwig 1994)

38. Four preparation types were used
Effects of Preparation and Luting system on All-ceramic computer generated crowns (Mormann – Int. J Prosthodont 1998)
Examined the effect of inside crown form on fracture strength of cemented and bonded crowns.
Four preparation types were used

39. Machined crown were placed on abutments
a. Without any media as control group
b. Cemented with zinc phosphate
c. Bonded
And were loaded until fracture

40. RESULTS
Zinc phosphate cemented crowns showed significant increase of fracture load values compared to uncemented control crowns.
Fracture load values of bonded crowns were significantly higher than those for cemented crowns.
Bonded crowns with thick occlusal dimension showed the highest fracture load values.

41. He concluded that bonded all ceramic CAD-CAM crowns with defect oriented inside morphology and increased occlusal dimension showed high fracture load values.

42. PROCERA CAD/CAM SYSTEM TITAN CAD/CAM SYSTEM CELAY CAD/CAM SYSTEM
CEREC CAD/CAM SYSTEM
PROCERA CAD/CAM SYSTEM
TITAN CAD/CAM SYSTEM
CELAY CAD/CAM SYSTEM
CICERO CAD/CAM SYSTEM
LAVA CAD/CAM SYSTEM

43. CEREC SYSTEM Chair side economical reconstruction of esthetic ceramic.
- Cerec 3 – Feb’ 2000

44. CEREC CAD-CAM SYSTEM Limitation Cannot mill the occlusal surface
Only inlays and onlays

45. CEREC – 2 CAD-CAM SYSTEM Milling of occlusal surface possible
Inlays, Onlays, veneers and crowns
Milling time approx. 10min

46. The grinding precision of the cerec-2 is 2
The grinding precision of the cerec-2 is 2.4 times higher than cerec system (Mormann 1997)

47. CEREC – 3 CAD-CAM SYSTEM Advanced version Technical improvements
Designing and grinding- less
time (27%)
Grinding unit – 2 cutters

49. Marginal and Internal Fit of Cerec 3 Cad/CAM All Ceramic Crowns (Kojima – Int. J Prosthodont 2003)
Examined the effect of the occlusal convergence angle of the abutment and the computer luting space setting on the marginal and internal fit of cerec 3 CAD-CAM all ceramic crowns.
Mandibular second premolar all ceramic crowns were fabricated for nine different conditions using cerec-3 CAD-CAM system

50. Occlusal convergence angle of 4,8 and 12°
Luting space settings of 10, 30 and 50µm.

51. Total Oclusal Convergence
Luting Space
10µm
30µm
50µm
Marginal Gap 4° 8°
12°
108 95 66 53 61 67 55
Internal Gap
119
135
136
116
132
141
162
146

52. He concluded that when the luting space was set to 30µm, crowns with a good fit could be fabricated with the cerec 3 system, regardless of the occlusal convergence angle of the abutment.

53. PROCERA CAD-CAM SYSTEM
Nobel Biocare
Initially introduced in 1985
Titanium copings
Utilizing the latest scanning, CAD-CAM and manufacturing technologies
Procera Allceram crown in 1991
Procera Allceram bridge in 1999

54. TITANIUM CROWN AND FPDS SUBSTRUCTURE
Reading
Milling
Spark erosion

55. READING The prepared die is attached
Contact probe registers the surface

56. MILLING
The probe tip of the reader and the tip of the milling tool are of same size.
The graphite electrode is milled

57. SPARK EROSION Used in dentistry since 1982
Graphite electrode is fitted
Removes the metal by electricity in the form of controlled sparks to fabricate copings.

59. PROCERA ALL CERAM CROWN
Composed of densely sintered, high purity aluminium oxide coping that is combined with low-fusing Allceram veneering porcelain.

60. Preparation of the tooth
Computer assisted design
Manufacture of the coping
Addition of the veneering porcelain

61. PREPARATION OF THE TEETH
Recommendations for the preparation
Depth orientation grooves 1.5mm
Incisal reduction – 2.0mm
Axial reduction – 1.5mm

62. Rounded, smooth contours and lack of line angles

63. Impression is made
Die is fabricated
Articulated

64. COMPUTER ASSISTED DESIGN
Die is oriented vertically
Tip of the scanner probe is brought in contact
As the platform rotates, one data point is collected at every degree around the 360° circumference of the die.

65. More than 50,000 data points are registered
Scanning takes 3min
More than 50,000 data points are registered
Verified on the computer screen for completeness
Vertical gap

66. The finish line of the preparation is marked by the operator at every 10° around the circumference of the die.

67. Coping design is selected
Merged with the die and its finish line.

68. MANUFACTURE OF THE COPING
When the design of the coping is finalized, it is saved and transferred through a modem communication link to Procera Stanvik AB in Stockholm Sweden, where the coping is fabricated.

69. ADDITION OF THE VENEER PORCELAIN
The coping is sent by mail to the dental laboratory where the ceramist finalizes the restoration by addition of Allceram veneering porcelain to create the appropriate anatomic form and esthetic qualities.

71. Titanium copings veneered with Procera Ceramics : A longitudinal clinical study (Nilson - Int.J Prosthodont 1994)
In 1989, 47 titanium copings veneered with a low fusing ceramic were fabricated for 24 patients. 44 crowns could be examined after a period varying between 26 and 30 months.

72. CDA ratings for surface and color changed markedly from the Excellent to the acceptable level.
For marginal integrity it was recorded as satisfactory for all crowns and a large majority were rated excellent.

73. A comparison of the Fit of Spark – Eroded Titanium Copings and cast gold alloy copings (Wickens - Int. J. Prosthodont 1994)
Compared the fit of spark eroded titanium and cast gold alloy copings and showed that the overall fit of titanium copings was comparable to that of gold copings. In marginal areas, the space between die and coping was found to be larger for spark eroded than cast copings.

74. TITAN CAD-CAM SYSTEM
Production of metal copings for porcelain fused to metal restorations
Digitizing
Processing
Milling

75. Conventional Technique
Preparation
Impression
Die
Waxing
Investing
Casting
Digitizing
Processing
Milling
Conventional Technique
CAD/CAM system

76. DIGITIZING Die is fabricated Mounted on the digitizer
Data are recorded
Short circuited

77. Divided into 200µm x 200µm squares
Digitized at least twice
The finish line and the adjacent 1mm area are recorded first

78. PROCESSING
The main parameters for the copings are then determined – The gap between the coping and the die
- The width and shape of the coping

79. MILLING
Uses titanium alloy dummies of various widths in the form of disks or blocks
Milling device consist of two major units
- A rotatory drilling element with interchangeable bores
- A mobile platform to which the dummy is fixed

80. Rough milling inside the coping
Three steps
Rough milling inside the coping
Fine milling inside the coping
Rough external milling

81. MULTIPLE UNIT RESTORATION
Steps same as for the single unit restoration
It uses master cast made from a multiple unit impression
Master cast allows the computation of each individual tooth and of the corresponding residual ridge

82. Relative parallelism between the CAD-CAM coping margin and the tooth margin in comparison with uneven appearance of same area of a coping manufactured with traditional casting technique

83. CELAY CAD-CAM SYSTEM
Introduced in 1992 by Mikrona Technologies, Switzerland
Inlays, onlays, crowns and bridge framework
Not a true CAD-CAM system
Many features in common

84. A light cured composite replica Either directly or indirectly
Replica is mounted
Scanning tools used to trace
Milling tools removes ceramic

85. Bulk reduction by rough diamond milling disc
Fine milling disc
Contouring by diamond point
Milling time 40mins – three unit bridge

87. CICERO CAD-CAM SYSTEM Computer integrated crown reconstruction
First technical concept- by Denisson et al in 1999
Crowns with different ceramic layers such as high alumina core, dentinal and incisal porcelain for maximal strength and enhanced esthetic.

88. Preparation of Scan Model Design of crown layer build-up
STEPS
Preparation of Scan Model
Optical Scanning
Design
Occlusion
Design of crown layer build-up
Production process

89. PREPARATION OF THE SCAN MODEL
Model is marked with black/white contrast

90. OPTICAL SCANNING Obtained by laser scanning of the cast
Upto 1,00,000 surface points are recorded per minute

91. DESIGN Appropriate tooth selected
Mesial and distal contact are outlined
The margin line of new crown is adjusted

92. OCCLUSION
The new crown is superimposed on the opposing teeth to check for occlusion

93. DESIGN OF CROWN LAYER BUILD-UP
The interior and exterior tooth surfaces are designed and interface surfaces between cement and ceramic core and between dentin and incisal porcelain are defined.
Thickness of the ceramic core of 0.7mm
Ceramic core – die cement thickness of 0.02mm is adjusted.

94. PRODUCTION PROCESS Refractory block is fitted
Negative of the inside surface of the crown is milled

95. - Diamond cylinder of 5.3mm dia - Diamond rounded disk of 09.3mm dia
Cutting tools used
- Diamond cylinder of 5.3mm dia
- Diamond rounded disk of 09.3mm dia
- Diamond pointed tool of 0.9mm dia
Automatically exchanged

96. High strength aluminium oxide based ceramic is applied and sintered
Ceramic is grounded to calculated oversize to compensate the shrinkage that will occur during the final sintering

97. Dental porcelain applied and fired
After firing block is placed on milling machine and interface between dentinal and incisal porcelain is milled

98. Translucent incisal porcelain is applied, fired and milled

99. LAVA CAD-CAM SYSTEM Produce high strength all ceramic crowns and FPD’s
Uses yttrium tetragonal zirconia polycrystals (Y-TZP) based material
Introduced as a hip replacement material in early 1990’s
High fractured strength 900 – 1200MPa and biocompatibility

100. Special scanner (Lava Scan) Computerized milling machine (Lava Form)
A sintering Oven (Lava Therm)
CAD-CAM software technology

101. Saw cut working cast is mounted on the scanner
STEPS IN FABRICATION
Saw cut working cast is mounted on the scanner
The configuration of the tooth preparation are scanned
Scanning process takes
- Crown – Approx.5min
- 3 unit FPD – Approx.12min

102. - Crown coping – Approx.35min - 3 Unit FPD – Approx.75min
Produces an enlarged framework to compensate shrinkage during sintering process.
Average milling time
- Crown coping – Approx.35min
- 3 Unit FPD – Approx.75min

103. The framework is sintered in the Lava Therm
Pre programmed to run for 8hrs, including the heating and cooling phases.
The sintered framework is then veneered

106. To conclude,
Computer graphics and CAD-CAM have revolutionized dentistry. It is now possible to provide equivalent of a cast restoration in a single appointment

107. BIBLIOGRAPHY Philips Science of Dental Material, - ANUSAVICE
Art & Sciences of Operative Dentistry- STURDEVANT’S
Dental Clinics of North America – Fixed prosthodontics
Fundamentals of Fixed prosthodontics – SHILLINGBURG
Contemporary fixed prosthodontics – ROSENSTEIL
Restorative dental material – CRAIG

108. Thank you
Thank you