The document discusses the evolution and advantages of digital impressions and CAD/CAM technologies in dentistry, highlighting systems like CEREC for real-time restoration processes. It outlines both benefits, such as patient satisfaction and efficiency, and drawbacks, including high initial costs and scanning limitations. Additionally, it details intraoral and extraoral scanning methods, data acquisition processes, and potential errors during scanning.

1. DIGITAL IMPRESSION

2. INTRODUCTION
• Computer-aided design and computer-aided manufacturing (CAD/CAM)
have been employed in the fabrication of restorations, especially ceramic
crowns and fixed dental prostheses (FDPs), since the 1980s
• CEREC was the first commercially available digital impression system.
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3. IT IS POSSIBLE TO SCAN A PATIENT’S
ORAL CAVITY, DESIGN AND CREATE
RESTORATION AND FINALLY BOND IT
IN THE PATIENT’S MOUTH IN THE
COURSE OF ONE DAY.
Click to add picture

4. ADVANTAGES OF DIGITAL IMPRESSIONS:
1. Easy to correct, manipulate, or recapture images.
2. No use of impression material and no need for trays and gypsum.
3. Do not need to disinfect before sending information to the laboratory
4. Real-time visualization and evaluation
5. Saving time and increasing patient satisfaction (e.g. gag reflex).
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5. DISADVANTAGES OF DIGITAL IMPRESSIONS:
1. Initial cost of equipment and software maintenance fees
2. Cannot capture subgingival margins if obscured with blood, saliva, or
tissue.
3. Unable to accurately capture images of the edentulous arches
4. Scanning patterns need to be followed as per manufacturer’s
recommendations
5. Learning curve can be difficult for some individuals
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6. CAD-CAM IS DIVIDED INTO:
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CAI
Computer-aided impression
Scanning through intraoral or extraoral scanners
CAD
Computer-aided design
Using the software to design and visualize the restoration
CAM
Computer-aided manufacturing
Software gives orders to the milling machine to fabricate the restoration

7. HOW DOES IT WORKS
7
Data
acquisit
ion
Designin
g phase
(CAD)
Manufacturin
g phase
(CAM)

8. • Gathering the information or data from the prepared teeth and the adjacent
structures using a scanner and then converted into optical impressions.
• A scanner is a technological device that uses light and special sensors to obtain
digitalized images of any object. It could be either:
• Intraoral that scans the preparation inside the patient’s mouth.
• Extraoral that scans a gypsum cast (3D model).
DATA ACQUISITION:
Fasbinder DJ. Digital dentistry: innovation for restorative treatment. Compend Contin Educ Dent 2010;31(4):2–11.

9. INTRAORAL SCANNING
• Higher cost (machines)
• Easier in use
• Can scan intra orally or extra orally
• Slower in full arch
• Cant scan big objects as articulator

10. EXTRAORAL SCANNING
• Less expensive
• Needs impression and ditching for the cast in case of preparation
• Only work extra orally
• Faster in full arch and articulator scanning also in scanning
impression

11. 1- Chair side 2-
Laboratory
system
chairside
CAD/CAM full
system
Chairside scanners/lab milling
(Integrated chairside laboratory system)
• has its own scanner
and milling units
• Example cerec
• has only a scanner without designing
capabilities
• must be connected to an open
laboratory scanner for designing of
the restoration.
• Example; Carestream CS 3500
General classification of CAD/CAM systems
Abdullah A.O, Muhammed F.K, Zheng B, Liu Y. An Overview of Computer Aided Design/Computer Aided Manufacturing
(CAD/CAM) in Restorative Dentistry. J Dent Mater Tech 2018; 7(1): 1-10.

12. laboratory
CAD/CAM
CAD unit
CAM unit
2-Laboratory system
has its own scanner to scan
impression or cast and
milling units
Example Planmeca
has only the scanner
Example 3 Shape; Dental Wings 7 series
retains the milling machine unit
Example Sirona; M5

13. Intraor
al
system
s
CEREC
TRIOS
E4D
iTero
Lava
C.O.S

14. They vary from each other in terms of key features
such as
 Working principle,
 Light source
 The necessity of powder coat spraying,
 Operative process
 And output file format

15. 15
CAD/CAM SYSTEMS AND DATA SHARING:
Open systems
Allow the adoption of the original data by
CAD software and CAM devices from
different companies.
Closed systems
No interchangeability between different
systems from other companies. All
procedures (data acquisition , virtual
design , and restoration fabrication by the
same company).
Miyazaki T, Hotta Y, Kunii J, et al. A review of dental CAD/CAM: current status and future perspectives from 20 years of experience. Dent Mater J

16. ERRORS DURING
INTRAORAL
SCANNING
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17. 1. INADEQUATE GUM RETRACTION
ISSUE:
IF THE GUM IS NOT RETRACTED
PROPERLY, THE SCANNER MAY
NOT CAPTURE THE FULL MARGIN,
LEADING TO INACCURACIES.
Use a retraction cord or other methods to
expose the margin clearly before
scanning.
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18. 2. Moisture and Saliva Interference
MOISTURE, SALIVA, OR BLOOD ON
THE TOOTH SURFACE CAN AFFECT
SCAN QUALITY AND CREATE
DISTORTED IMAGES.
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keep the area dry by using air or
suction to clear away saliva. some
scanners may also require
powder for better imaging.

19. 3. INCOMPLETE COVERAGE OF THE ARCH
ISSUE: MISSING AREAS, ESPECIALLY ON
HARD-TO-REACH POSTERIOR TEETH, CAN
LEAD TO AN INCOMPLETE
Ensure full coverage by systematically
scanning from different perspectives,
particularly for posterior teeth.

20. 4. POOR SCANNING TECHNIQUE
ISSUE: MOVING THE SCANNER TOO
QUICKLY OR INCONSISTENTLY CAN LEAD
TO MISSED DETAILS OR UNEVEN SCANS.
Maintain a smooth, steady motion and follow the
scanner’s recommended technique, covering all
surfaces systematically.

21. 5. INCORRECT BITE REGISTRATION ISSUE:
MISALIGNMENT OF THE UPPER AND LOWER
ARCHES DURING THE BITE SCAN CAN LEAD TO
OCCLUSAL ERRORS. Ensure the patient is in a natural bite
position and confirm the bite scan
alignment before saving it.