Introduction to Digital Dentistry

INTRODUCTIONTO
DIGITAL DENTISTRY
Prepared by: Eng. IbrahimTayyan

Contents:
■ Definition of Digital Dentistry
■ Dental Radiography
■ Dental CAD/CAM
■ Integrating Radiography with CAD/CAM
■ Dental Surgical Navigation System
■ Computer Assisted Anesthesia System
■ Appendix a: Dental Software
■ Appendix b: Networking and AdvancedWindows Settings

DEFINITION OF DIGITAL
DENTISTRY
Definition, Uses and Advantages

What is Digital Dentistry
• It is incorporating dental equipment and devices with computer or computer based components to
perform several dental procedures instead of using conventional methods and using mechanical
and/or electrical tools
• Computer aided equipment and devices are mainly used for diagnosing procedures and for dental
restoration planning (design and manufacturing or printing)

• Using and incorporating advanced or latest technologies available to
dental treatments and procedures facilitate dentists work
• This means:
• More precise results
• Less opportunities of errors
• Less time consuming
• Lowering costs by minimizing consumables needed
• Patient satisfaction
• Efficient file management systems
• State of art clinics

• Major challenges against using digital dentistry:
• Expensive capital equipment
• Some dentists are unfamiliar with using computers
• Learning curve
• Dentists and lecturers still sticking on using old traditional
procedures

DENTAL
RADIOGRAPHY
Using X-ray Beam to Produce Images for Diagnostic Uses

Medical Imaging
Medical imaging is the technique and process used to create images of the human body (or parts and
function thereof) for clinical purposes (medical procedures seeking to reveal, diagnose, or examine disease)
or medical science (including the study of normal anatomy and physiology)
Main Categories:
X-Ray Radiography
Ultrasonography
Nuclear Medicine
Magnetic Resonance Imaging

Fundamentals of X-Ray
Electromagnetic waves: Also known as Electromagnetic Radiation is a form of energy waves that have both
an electric and magnetic field and transmit energy and travel through space and vacuum

X-RayTechnologies for Dentists
• Dental X-ray technologies are used to find hidden dental structures, malignant or benign masses, bone
loss, and cavities
• A radiographic image is formed by a controlled burst of X-ray radiation which penetrates oral
structures at different levels, depending on varying anatomical densities, before striking the x-ray
detector
• Materials or substances with higher densities appear lighter than materials with lower densities due
to radiation penetrates lower densities easier than higher ones (radiopaque)
• Teeth appear lighter for example because less radiation penetrates them to reach the detector, while
blood vessels appear darker since radiation penetrates it easily (radiolucency)
• X-ray have properties of penetration, absorption, scattering, ionization and attenuation, but they
cannot be reflected, refracted nor deflected by magnetic or electrical field

History of X-Ray and its Usage in Dentistry
• Wilhelm Conrad Röntgen a German mechanical engineer and
physicist discovered and produced x-ray on 8th of November 1895
• Max Gebbert a German mechanic and a co-founder of the
company Reiniger, Gebbert & Schall (RGS) met withWilhelm
Röntgen only after 3 days of x-ray discovery
• Few months later, RGS produced the first commercial intraoral x-
ray in history
• In 1934, Siemens-Reiniger-Werke (SRW) brought the famous
"Röntgenkugel" X- ray sphere onto the market and at the time it
was the smallest X-ray device in the world

History of X-Ray and its Usage in Dentistry
• In 1961, the first OPG system was commercially produced named
Panorex OPG
• In 1995, the OPG system has been digitalized for the first time and
it was named DXIS
• In 1996, the first CBCT has been introduced and was named
Newtom 3000

Types of Dental Radiographs
Intraoral Imaging Extraoral Imaging

Intraoral Imaging
• Intraoral imaging as the name indicates, is taking images of the teeth while the x-ray detector is inside
the patient’s mouth
■ Missing teeth
■ Impacted teeth
■ Dental caries
■ Periodontal disease
■ Tooth abnormalities
■ Retained roots
■ Cysts and tumors
■ Tooth Structure
■ Supporting Bone
Main Indications of intraoral imaging:

Types of Intraoral ImagesViews
Periapical Bitewing Occlusal

Intraoral Imaging
PeriapicalView is the most widely used imaging view.
It shows the whole tooth, from the crown to beyond the end of the root to where the tooth is
anchored in the jaw.
• Detect apical inflammation/ infection including
cystic changes
• Assess periodontal problems
• Trauma-fractures to tooth and/or surrounding
bone
• Pre/ post apical surgery/extraction..
• Detect any presence or position of unerupted
teeth
• Endodontics root canal treatment.
• Evaluation of implants.
Main Indications of Periapical Imaging:

Intraoral Imaging
Bitewing View show details of the upper and lower teeth in one area of the mouth. Each bite-wing
shows a tooth from its crown to about the level of the supporting bone
Bite-wing X-rays are used to detect decay between teeth and changes in bone density caused by gum
disease.They are also useful in determining the proper fit of a crown (or cast restoration) and the
marginal integrity of fillings.This type of X-ray shows the dentist how these teeth touch one another
(or occlude)

Intraoral Imaging
OcclusalView offers a clear view of the floor of the mouth to show the bite of the upper or lower
jaw.This kind of X-ray highlights children’s tooth development to show the primary (baby) and
permanent (adult) teeth

Intraoral X-ray Components
Extension arm
PID or cone
Exposure
Switch
Control Panel
X-rayTube Housing

Extension Arm: The dentist adjust the arm by extending it and changing the position of it to place it
near the patient’s cheek to take an image for region of interest

X-ray tube is in housed inside its housing cover Housing cover with PID

Used to set the patient size, the exposure
time and kVp for some machines
Keep pressing on this button to release exposure
to the patient in terms of milli seconds

Factors Affecting X-ray Beam
• Focal Spot
• Collimation
• Filtration
• kVp
• mA
• Time Exposure

• Focal Spot is the small region or spot in the anode where the electrons hit the region to produce x-
ray photons
• Smaller focal spots give better image quality and increased sharpness, while larger focal spots
produce blurring in the image

• Collimator: it is a device that is used to regulate the size of the beam leaving the x-ray tube and
strict it to a smaller beneficial size and necessary area
• PID: also known as position indicating device aids in collimation and guides the direction of the x-
ray beam which improves and standardizes dental radiographic imaging and reduces the patient's
risk of radiation exposure

• An Aluminum disk is placed between the collimator and the exiting window of the x-ray tube, to
absorb unnecessary x-ray wavelengths (weak long wavelength rays)

• There are two types of filtrations:
1. Inherent Filtration: filters that are components of the x-ray tube (tube wall, insulating oil, inner
aluminum disks and other inside components)
2. Added Filtration: filters that are added to the x-ray tube to meet safety standards
• Total Filtration is the sum of inherent and added filtrations and it should not be less than 2.5 mmAl
• Collimation, filtration and focal spot play an important role in limiting unnecessary x-ray beams
to reach the body, therefore reduces risk of unhealthy conditions and makes the image sharper
and better and eliminating blurring

• Kilovolt power or peak voltage: controls the force that attracts electrons to anode
• As kVp increases, the penetration power of the x-ray beam increases, so it penetrates denser
tissues but the contrast of the image decreases
• Contrast: is the difference in luminance, hue or color that makes an image distinguishable

• Milliampere: It is the current passing through the tungsten filament to produce electrons
• Raising the mA raises the heating of the coil, which means more x-ray photons are produced and
emitted and therefore increases the darkness of the image

• PeakVoltage is also known as controlling the quality of x-ray beam
• Milliamperage is also known as controlling the quantity of x-ray beam
• Also the distance between the x-ray source and the object plays role in the intensity of the image

X-Ray Machines
• DC X-ray machines are slightly better than AC in terms of safety for the patient, since less
radiation is exposed and radiation released is mostly useful ones
• In terms of image quality, there are no proven studies that DC is better nor vice versa
• KVP used in intraoral x-ray: normally fixed at 70 kVp or 60 kVp with some machines you can
choose either 60 or 70 kVp.
• mA used in intraoral x-ray: normally fixed at 3.5, 7 or 8 mA
• Focal Spot used in x-rays is usually 0.4 or 0.5 mm

X-ray Detectors
X-ray Films Direct Digital Imaging:
Intraoral Sensors
Indirect Digital Imaging: PSP
Imaging

X-ray Films
• When using traditional film, X-rays interact with a layer on the film called the film emulsion, which
contains silver halide crystals that absorb the radiation.The crystals produce a latent image of a tooth
and its surrounding structures, which becomes a visible image once the film is chemically processed.

Examples of Artifact Errors for Films
Double Image: 2 times exposure on
same film at different regions
Bended film Black line due to bended film

Wave like lines due to directing
the X-ray through the lead foil side
of the film back (Reversed Film)
Black spots: Developer contamination
before immersion into the developer
solution
Scratched Film

White Spots: Contamination with fixer
before processing
Smudge: Finger Prints

PSP Imaging
• PSP (photostimulable phosphor plate) is a cordless plate that is similar in shape and concept to
conventional x-ray films but differs in method of interpreting absorbed radiation to a readable image
• X-ray films are processed by chemicals called fixer and developers inside a manual or automatic film
processor, while PSPs are integrated to a PC via PSP scanner
• Photostimulable phosphor has the special property of storing the X-ray energy in a latent form and
releasing the same when stimulated by a laser energy in the scanner. Unlike x-ray films where the
stored latent image is visible by chemical processing

PSP ImagingWorkflow
• Stimulation with a scanning laser beam at a wavelength of 660 nm releases
electrons and then electrons will emit light at a wavelength of around 390 nm
• The PSP is simply moved in front of a fixed laser source.The laser beam is
deflected by mirrors onto the surface of the PSP
• After processing is complete, the scanner then erases the plate for reuse

PSP Imaging
• Displaying an image on a PC is much better than displaying it on printed films on an x-ray viewer
• You can manipulate the image, by changing the brightness and contrast, and you can do several
post enhancements on the image such as changing the sharpness, smoothness, inverting B/W,
colorize and even do some extra advanced filters so the image appears better
• You can also save patients’ data and manage files for all patients on the software easily

PSP Imaging
• Using PSP instead of film solved many of the films drawbacks but not all of them
• For example it has solved the errors due to contamination and misuse of chemicals, in addition to
lowering costs by eliminating the use of chemicals that costs some money every day
• However, it did not solve the errors issue due to mishandling of the phosphor plate, such as
scratches and smudge

Intraoral Sensors
• Using intraoral sensors, image will directly appear on the PC monitor after exposure has been taken with
less than 2 seconds (depending on computer’s speed)

Intraoral SensorsTypes
Wired Sensors Wireless Sensors
• Direct USB 2.0
• USB 2.0 cable + interface
• Ethernet
• RF wireless
• Bluetooth
• WiFi System

Intraoral Sensors
• Wired Sensors are used much more than wireless ones due to speed, no interruption, less expensive
and no noise artifact due to electromagnetic waves interference (such interference is widely seen in
RF ones)
• Regardless of sensor’s types, all of the intraoral sensors need 80% less radiation than conventional x-
ray films, which means much safer for the patient and the dentist
• You no need to retake exposure if the image obtained is of bad brightness, contrast and sharpness
unlike x-ray films.
• Sensors helped the endodontics a lot in endo treatment procedures, since along with apex locator
could easily take exposures during operation without the need to stop working till the film is
processed.Also the endodontic could easily take several continuous shots since image transferring
and displaying is much faster in addition to much more reduced exposure to the patient

Intraoral Sensors
Scintillator:Converts X-ray to light
Photodiodes: Convert light to
electrons
Integrated Circuit (CCD or CMOS)
X-ray Photons
Light
Electrons
Readable Data

Intraoral Sensors
• CMOS (complementary metal oxide semiconductor) and CCD (charge coupled device) image sensors
are two different technologies used for capturing images digitally
• Both types of imager sensors can convert light into electric charge and process it into electronic
signals
• Imaging sensors layers are integrated circuits for converting light into electronic signals
• In the case of a CCD sensor, every pixel’s charge is transferred through an extremely reduced
number of output nodes (often just one) to be converted to voltage, buffered, and sent off-chip as
an analog signal.
• In the case of a CMOS sensor, each pixel comes with its own charge-to-voltage
conversion, and the sensor often also features digitization circuits, amplifiers, and noise-
correction, so that the chip can output digital bits

Intraoral Sensors
• CCD sensors create high quality images with low noise (grain).They are more sensitive to light.
However, CCD sensors consume around 100 times more power than equivalent CMOS sensors.
• However, intraoral sensors use CMOS-APS technique instead of CCD despiteCCD has lower noise
interference than CMOS, due to the fact that if one pixel in a row is defected, all of the row gets that
defect plus it has a higher speed than CCD.
• CMOS manufacturing costs are less than
CCD

Intraoral Sensors
• Sensors in general comes in 2 or 3 different sizes
• Size 1 is the most used size as a standard universal size
for all patients
• Size 2 is used for bitewing imaging
• Not all sensor companies has size 0 (pediatrics)

Factors Affecting the Image Quality
• Grayscale, bit depth or dynamic range: it is the scale representing the range of gray color range,
measured in bits.
• Grayscale of 8 bit = 2^8 colors or shades
• 16 bit is the latest available in market which means 65536 colors

• Spatial resolution is quantified in the number of line pairs that can be distinguished per millimeter (lp/mm).A
line pair consists of a dark line and a bright line. So if one line is 5 microns wide, then a line pair will be 10
microns wide and there would be 1 mm/10 microns = 100 line pairs per millimeter.
• Spatial resolution is a measure of the smallest object that can be resolved by the sensor. It is a
measure of the accuracy or detail of a graphic display

• A pixel is the smallest unit of a digital image or graphic that can be displayed and represented on a digital
display device
• Each pixel has a unique logical address, a size of eight or 16 bits
• The smaller the pixel size, the better the image resolution and quality are

• CMOS-APS with CsI Sensor
• Bit Depth: 16 bits
• Theoretical resolution: 33.3 lp/mm
• Measured resolution: 28 lp/mm
• Pixel size at capture: 15 μm
• Gold inner cables instead of copper (more ductile and
can bear bending better)
• Replaceable Sensor cable
The highest quality available in the market has the following specifications:

Intraoral Sensor Pros
• No consumable costs at all (except for disposable sheath that costs around 100 fils)
• Much better resolution than x-ray films
• Rigid and robust. No errors due to bending nor scratch or even finger prints
• Long life time: not less than 500,000 exposures

Drawbacks of Intraoral Sensors
• Typically more expensive than x-ray films (Sensor may cost 2000 to 4500 JDs while x-ray films are
less than 80 JDs)
• Care must be taken when handling the sensor:
1. The cable could get cutoff due to excessive bending and kinking
2. The STRAIN RELIEF is a critical component, where the cable could be broken
3. Most of the sensors available in the market are not cable replaceable (if the cable breaks down, you have
to exchange the whole sensor)
4. In case of models where sensor is a USB built-in cable (the one where interface is not needed), cable can
easily be defected due to computer port issues and in this case you have to pay to exchange the whole
system

ComparisonTable
No Description Film Based PSP Sensor
1 Image Acquisition Indirect Indirect Direct
2 Radiation Dose High Medium Low
3 Image Process Chemicals Scanner and PC PC
4 Time to Process Few minutes Less than one minute Less than 2 seconds
5 Post Enhancement None Wide range Wide range
6 Life Span Single Use Unlimited Use Around 500,000 images
7 Output Hard Copy Soft and Hard Copies Soft and Hard Copies
8 Best Environment None Large Center Small to medium size centers

Techniques for Exposing Radiographs
• To obtain accurate and optimum image quality, the correct positioning of the x-ray detector
towards the x-ray cone is essential
• There are two used methods for positioning the x-ray
1. ParallelTechnique:The most widely used technique, where the receptor or detector is parallel
to the center tooth axis or perpendicular to the x-ray beam
2. Bisecting Angle: The X-ray beam is perpendicular to an imaginary bisecting angle formed by the
plane of the receptor and the central axis of the tooth

Examples of Bad Positioning
Cone Cutting: Cone not positioned toward the
receptor well

XCP Positioners
• These are positioners where the sensor or film is attached to it for precise parallel technique positioning
• They are color coded depending on region to be used
• Not all dentists use them due to being not that comfortable at setting up

Extraoral Radiography
• Extraoral Imaging (in contrast to intraoral): is taking image of the teeth,TMJ, sinus or maxillofacial
regions while the receptor is outside the mouth
Panoramic Radiography
Cephalometric Imaging
CBCT Imaging

• Panoramic imaging (aka orthopantomography) is a technique for producing a single image of the facial
structures that includes both the maxillary and the mandibular dental arches and their supporting
structures using focal plane tomography technique
• Tomography is a two-dimensional image of a slice or section through a three-dimensional object.
• Focal plane tomography is one type of tomography techniques available in imaging in general
• This type is proceeded by imaging a single plane, or slice, of an object) by simultaneously moving the X-
ray generator and X-ray detector so as to keep a consistent exposure of only the plane of interest during
image acquisition

Panoramic Radiography Principle
X-rayTube and
Generator
X-ray Detector (Film
Cassette or 2D sensor)
The patient stands between the x-ray
tube and the detector to take a
tomography for the region of interest
(full mouth)

The x-ray source and receptor, both are
attached on a rotating disk, while the
patient is positioned under the circular ring
on the center of the disk
This image illustrates how the disk or ring is rotated and how
the beam is exposed towards the receptor, with the direction of
the collimator opening

These 2 figures show the direction of the continuous x-ray
beam from its starting point (usually the right side of the
patient) and moves from behind his head while the receptor is
facing him till it reaches its end point

• Depending on whether you are using x-ray film cassette or an imaging sensor (CCD or CMOS), the image
will appear as below
• Measurements of lengths are never accurate for panoramic images as the image is normally not 1:1 due
to the nature of tomography procedure.
• Image size ratio for most panoramic machines is 1:1.19 with option of magnifying up to 25%

Panoramic Radiography Indications
• Impacted wisdom teeth diagnosis and treatment planning
• Periodontal bone loss and periapical involvement.
• Finding the source of dental pain, and when carrying out tooth-by-tooth diagnosis
• Assessment for the placement of dental implants
• Diagnosis, and pre- and post-surgical assessment of oral and maxillofacial trauma
• Temporomandibular joint dysfunctions and ankylosis.

Panoramic Radiography Indications
• Impacted wisdom teeth diagnosis and treatment planning
• Periodontal bone loss and periapical involvement.
• Finding the source of dental pain, and when carrying out tooth-by-tooth diagnosis
• Assessment for the placement of dental implants
• Temporomandibular joint dysfunctions and ankylosis.
• Targeted dentists: General dentistry, pediatrics, implantologists, periodontists, maxillofacial surgeons,
radiologists and sometimes ENT
• Panorama is rarely used by endodontics as 2D panoramic image does not give a detailed image of the
root canals like the intraoral ones

Paranasal Sinus

• There are two types of x-ray detectors used in panoramic machines: Cassettes or digital sensors
• Imaging companies no longer produce analog cassette types as it takes much more radiation than digital
ones, in addition to the companies movement towards using CBCTs instead of 2D panoramic machines

Image Quality Factors:
• Focal Spot: lower focal spots give better sharpness (0.5mm)
• Collimation: Reduces secondary radiation
• Filtration: Again 2.5 mm Al
• kV: Range used is typically from 60 – 90 kV
• mA: Range available is from 3 – 16 mA
• Pixel Size: The best machine available has a pixel size of 27 um
• Bit Depth: There is no higher than 16 bit
• SensorType: Most sensors are CCD instead of CMOS due to less noise
interreference and lower manufacturing costs. However, CMOS is also
available
• Calibration: Do calibration of sensor and diaphragm where necessary

How toTake an Image:
• For obtaining a good quality image, the way of positioning the patient in the panoramic machine is totally
essential to reduce white shadows (radiopacity artifacts) or black shadows (radiolucency artifacts) on
regions that are really not radiopaque nor radiolucent which causes diagnosis errors
• Also choosing the correct factors (kV and mA) gives an optimum image based on penetration and
brightness of different tissues according to patient’s sizes
• However, there are setting presets for each patient size and
buttons are located on the control panel

Technologies for Enhancing Image Quality:
• As it is seen in this photo, there is a white
vertical shadow in the middle of the image,
where the roots of the anterior teeth are not
that clear
• This shadow in the middle is an artifact appeared
from the spine of the patient
• Companies have their own techniques to reduce
this white shadow or even removing it
completely

At this point the x-ray KV is raised to
maximum value (90 KV) then it goes
back to normal chosen value
• Some companies for example, the machine itself
automatically raises up the kilovolt value up to its
maximum once it reaches the midpoint of the teeth,
then the kilovolt value returns back to the value the
personnel has chosen
• Other companies raise the milliampere value instead of
the kilovolt, but this gives extra unwanted dose to the
patient, and the image is not as good as using the
kilovolt raising technology
• Raising the voltage to maximum will increase the
penetration power of the beam in a way that the spine
will not appear on the display monitor

• Sometimes the image appears as in this photo
due to the movement of the patient’s head.
• During panoramic exposures, you have to make
sure that the patient stands still for around 20
seconds, as radiation time is around 14.1
seconds for standard panoramic programs
• Some companies to make sure that the head is not
moving, they use some special head temples or other
techniques to make the head stand still
Head temples

• There is a new technology called direct conversion where the x-ray photons are directly converted to
electronic signals instead of light where Cadmium telluride (CdTe) is used as an x-ray detector (flat panel
detectors)

Cephalometry:
Cephalometry: is the study and measurement of the head using radiography
Cephalometric analysis is used in dentistry, and especially in orthodontics, to gauge the size and spatial
relationships of the teeth, jaws, and cranium

Cephalometry:
• There is no machine that is used only for ceph imaging
• There is an additional arm that is attached to some
panoramic models as in the photos
• There are machines where you use the same sensor of
panoramic mode for ceph mode by removing the sensor
from the panorama machine to the ceph arm
Detachable Sensor
• Other machines use two sensors together,
one for pan and the other for ceph
• Unlike pan mode, the tube does not rotate
• Both sensor and tube translate in a straight
line direction

CBCT:
• Dental cone beam computed tomography (CT) is a special type of x-ray equipment used when regular
dental or facial x-rays are not sufficient.Your doctor may use this technology to produce three dimensional
(3-D) images of your teeth, soft tissues, nerve pathways and bone in a single scan
• It is similar to conventional CT scans in main principle but has some differences in the method of projecting
the x-ray beam

CBCT Images:
• Normally, you will have 5 different views
for any image you take
• The 3D model does not have any medical
indication as it is used for demonstration
uses only
• The 2D panorama is created as a result of
adjusting the jaw line of the 3 anatomical
planes
• However, some dentists use it to check
the bone and tissue thicknesses

CBCT ImageAnatomical Planes:
• Axial plane is widely used by endodontics to view the canals paths
• Coronal plane is used for maxillofacial treatments
• Sagittal plane could be used for nerve locating

CBCT Extra Modules
Implant Planning: By navigating the slices on a certain plane, you can trace the nerve location on the left or
right of the mandibular, in order to locate the implant with specific diameters and angulation in order to fit easily
and correctly on its position without hitting the nerve nor hitting the nearby teeth

CBCT Extra Modules
Endo Planning: Endodontics can also plan for endo files interments and apex locating planning

CBCT Extra Modules
Surgical Guides Designing: Implantologist can also design implant stents and mill it on a CAD/CAM milling
machine or a 3D printer to eliminate human errors while inserting the implant

CBCT Extra Modules
Sleep Apnea and Airway Analysis

CBCT:
• The advantage of usingCBCT is that even if the patient position was somehow not correct, you
can then readjust the jaw line of the patient on the software then the software reconstructs the
image again
• CBCT usually uses Digital Flat Panel Detector with a-Si technology (amorphous silicon) instead of
CCD ones
• The 3D image construction is always 1:1 image size
• Image quality depends on voxel size where it should be as small as possible (Voxel is the pixel cube)
• Many machines as 2D/3D hybrid machines so no need to buy a panorama and CBCT each one alone
• As field of view is raised, the voxel size gets higher, and therefore image quality lowers down

DENTAL CAD/CAM
Digital Method of Producing Dental Restorations

Preface:
Dental Restorations: are the various ways the dentist can replace or restore missing teeth or missing
parts of the tooth structure to restore the function, integrity, and morphology of the missing structure
There are two main types of restorations:
• Direct Restoration: Direct tooth restoration involves placing
a filling into a prepared tooth cavity immediately
Teeth can be filled with gold, silver amalgam, or tooth-colored
plastic and glass materials called composite resin fillings
• Indirect Restoration:The restoration is fabricated outside the
mouth before attaching it to restore the missing structure
Indirect Restorations are usually made from biomaterials
that resemble the natural look of the tooth such as glass
ceramic porcelains and zirconia

Preface:
Types of Indirect Dental Restorations
• Inlays are similar to fillings but, rather than using malleable
materials, are created from a dental impression using
porcelain
• Onlays are more extensive versions of inlays. Rather
than restoring an area of fracture or decay, an onlay would
replace any bits of tooth that have broken off
• Both inlays and onlays are used to restore missing
fractures on the posterior teeth

Preface:
• Dental crowns: also known as dental caps, are
appliances that completely cover the surface of a
tooth.They are typically bonded to a prepared
surface with dental cement, which improves both the
strength or appearance of a tooth
• Whether the restoration to be placed is an inlay/onlay
or crown, preparation of the tooth’s margin line must
be made by the dentist as a first step
• Dental margin is the interface between the tooth and the
material that a dentist replaces missing tooth structure
• For a margin to be considered “good” it should have a
minimal gap between the restorative material and the
tooth, not be too short and not be too long or over
contoured

Preface:
• Veneer: is a thin layer or shell of porcelain that can replace
or cover the enamel of a damaged, stained, or misshapen
anterior tooth
• Also a veneer preparation must be done by the dentist
in order to place it
• Veneers have low thickness (less than 0.5 mm)

Preface:
• Bridges: are artificial teeth that are affixed between
real ones to fill in a gap where teeth have been
removed or are missing
Pontic
Abutment
Tooth
MissingTooth
Crown
(Retainer)
• Pontic:The artificial tooth that replaces a missing
natural tooth
ConnectorTypes of Indirect Dental Restorations:

Preface:
Types of Indirect Dental Restorations:
• Dental implant: is a surgical component that
interfaces with the bone of the jaw or skull to
support a dental prosthesis such as a crown,
when the tooth or teeth are missing
• Dental Implants are usually made of titanium
due to its high compatibility
• Abutments (not to be confused with natural
teeth abutments), are either ready made
(titanium) or custom made (fabricated to
meet the size and other parameters
requirements
• Implants are of different types and systems

Conventional Dental Restoration Procedures
• The dentist first attempt the restoration preparation procedure (e.g bridge) to
the patient
• The dentist will then take an impression of the upper and lower jaws of the
patient
• A dental impression is a negative imprint of hard (teeth) and soft tissues in the
mouth from which a positive reproduction (cast or model) can be formed
• This is done by pouring an impression material (such as alginate, silicone polymers
and others) on an impression tray and press hardly on the patient’s mouth, to
produce an imprint of the occlusal surface of one jaw, where the extra silicone or
alginate will be withdrawn through the pores that are found on the impression
tray
• Impression trays could be reusable (autoclavable stainless steel) or plastic ones
(disposables)
• Taking an accurate impression is one of the more difficult procedures in
dentistry, requiring careful retraction or removal of soft tissue around
preparation margins, hemostasis, and selection of an appropriate impression
material and tray for the technique used

Conventional Dental Restoration Procedures
• The dentist then sends the dental impression to a dental
lab technician or dental lab
• The technician will then take the impression and flows
a gypsum dental stone or plaster to create a replica of
the patient's anatomy known as a dental cast
• The lab technician then waxes up and casts a metal
fixed restoration or substructure, and/or incrementally
places and bakes ceramic material for an esthetic
restoration

ConventionalTechnique Drawbacks
• High chances of material and operator errors at the impression making, model- and die-pouring, and
laboratory stages of the procedure
• Some materials may lack quality
• Time Consuming (usually from 2 days to 2 weeks)
• It is never possible to provide a custom-fabricated, single-visit fixed restoration

What is CAD/CAM
• Computer-aided design (CAD) is the use of computer systems to assist in the creation,
modification, analysis, or optimization of a design.
• CAD is most commonly associated with the use of an interactive computer graphics software,
referred to as a CAD system or software
• Computer-aided design systems are powerful tools in mechanical design and geometric modeling of
products and components.

What is CAD/CAM
• To increase the productivity
• To improve the quality of the design
• To uniform design standards
• To create a manufacturing database
• To eliminate inaccuracies caused by hand-copying of drawings and inconsistency between drawings
Why do we use a CAD Software

What is CAD/CAM
• Computer-aided manufacturing (CAM) is the use of computer software to control machine
tools and related machinery in the manufacturing of work pieces
• CAM may also refer to the use of a computer to assist in all operations of a manufacturing plant,
including planning, management, transportation and storage
• Computer-aided design and computer-aided manufacturing are combined as CAD/CAM systems
• A designer uses CAD software to make an exact model of the object he wants to manufacture
• Then the design is downloaded to a CAM software or hardware which in turn controls the CNC (Computer
Numerically Control) machine which makes the product

What is CAD/CAM
• Increases productivity
• Better quality
• Easy to modify design usingCAD software
• Reduced design time
• Reduced production costs
• Reduced human errors
Benefits of CAD/CAM Systems:

Usage of CAD/CAM in Dentistry
• Dental CAD/CAM system is an alternative procedure for producing dental restorations made up from
ceramic materials and zirconia
• There are 3 different CAD/CAM Systems available:
1. Chairside System (For clinics)
2. Labside System (For dental labs)
3. Integrated System (Part of it is at a clinic and the other part is at a lab)

Chairside CAD/CAM
• The chairside system consists mainly of three components and in some cases you need some extra
equipment
Intraoral Scanner Software Milling Machine

Chairside CAD/CAM
• Instead of taking alginate
impressions, the dentist uses
the intraoral scanner to
acquire digital impression for
the patient
• After completing the
scanning of both jaws the
software will then reconstruct
acquired images to create a
3D model
• The dentist will then draw the
margin on the designated
tooth or teeth

Chairside CAD/CAM
• The software will then make an initial proposal
or a design of the restoration to give the best
fit with the best anatomical shape.The dentist
also has an option to edit the design to meets
his satisfaction
• After the design is finished, the dentist will
then give an order to the milling machine to
start fabricating exactly the same designed
restoration.Then the dentist is ready to place
it on the patient’s mouth

Chairside CAD/CAM
• The Overall process of creating one single crown would not take longer than 20 minutes for an expert
CAD/CAM user
• The chairside CAD/CAM system has eliminated the need for a lab technician to do most of the restorations.
Chairside CAD/CAM is capable of doing the followings:
1. Inlays
2. Onlays
3. Crowns
4. Veneers
5. Bridges (up to 9 units full anatomy or 12 unit frameworks)
6. Zircon abutments for single implant
7. Surgical guide for single implant placement
8. Screw-retained crowns
9. Multi-layer crowns (abutment then crown)
Frameworks or cores: similar to a prepared crown

Chairside CAD/CAM
Advantages of Chairside CAD/CAM Systems

Lab Side CAD/CAM
• The labside system consists mainly of three components and in some cases you need some extra equipment
Extraoral Scanner Software Milling Machine

Lab Side CAD/CAM
• The lab technician will either scan
the impression tray or the cast
• The software will create the model and the lab
technician has to draw the margin, and the software
creates a design for the tooth or teeth

Lab Side CAD/CAM
• After the design is finished, the lab
technician will then give an order to
the milling machine to start
fabricating exactly the same
designed restoration. Then he will
send it to the dentist
Labside CAD/CAM can do extra tasks that a chairside CAD/CAM
couldn’t
1. Full arch bridges: 14 or 16 unit bridge
2. Multi abutments for a bridge: Bridges that has more than one
implant placed, and needs more than one zircon abutments
3. Partial Frameworks Prosthesis: Removable restorations
4. Night Guards and Splints
5. Multi surgical guides
6. PMMA Dentures
7. Titanium Abutments

Integrated CAD/CAM
• The dentist may scan the patient’s teeth and
send it by internet connection to a lab so he
will continue designing it and milling
• This procedure could be used for complicated
cases or to reduce the cost of buying the
whole system

CAD/CAM Milling Machines
• Materials to be milled in general comes in different variant shapes: Block or Disc
• They also come in different sizes and in different color shades
Blocks (aka ingots)
Discs (lab technicians may
call it block or blank)

• There are 2 types of milling machines: 4-axis and 5-axis
4-axis machine 5-axis machine

• Motors that are used to mill or grind the materials are either air-driven spindle types (needs to be
connected to a compressor) or DC brushless motors (electric-driven)
Air Spindle Brushless DC
Motors

• Depending on type of material, the machine will either grind or mill the material
• Grinding is the process where the machine will start production from the top of the block till the end
• Milling is when the machine’s motor goes on different directions to make the core of the restoration then
it starts its final finishing of the restorations details
• Grinding is slower but gives better details of the restorations
Grinding Milling

• Depending on type of material and also model of the machine, milling/grinding processes are
either wet or dry milling
Wet Milling: Using RO water
mixed with small amount of
lubricant to protect burs from
failure
Dry Milling

CAD/CAM Materials
No Material
Flexural
Strength
(MPA)
Indications Aesthetic
1 Feldspar Ceramics 120 -140 Inlays, Onlays, Anterior
Crowns, veneers
Most Aesthetic
2 Lithium Disilicate 345 Veneers, Crowns, up to 3
unit bridge
HighlyAesthetic
3 Lithium Silicate 200 - 650 Veneers, crowns, inlays,
onlays
Very HighAesthetic
4 Translucent Zirconium 950 - 1200 Crowns, up to 9 unit full
anatomical bridges
Least Aesthetic
5 Non-Translucent ZrO2 1100 - 1300 Frameworks up to 16 unit
bridge
For core productions only
6 Cobalt-Chrome 1300 - 1900 Frameworks For core productions only

CAD/CAM Ovens
At some cases, the dentist may put
the resultant restoration on a
glazing oven to give extra
translucency or to give extra glazing
effect on the teeth
Also the oven is used for
crystallization of some materials
Materials that are made from Zircon needs to be sintered inside the
sinter tray of the sintering furnace
Zircon when it is dry milled, the resultant size is enlarged and
seems to be powdered like.
The machine will raise the temperate to around 1500 C to do
sintering process.
Sintering: Process where zircon reaches near to its melting point,
then the zircon particles shrink together, giving translucency and
hardness

INTEGRATED
IMPLANTOLOGY
Integrated CAD/CAM with CBCT for Producing Surgical Guides

Surgical Guides
• A stent is an appliance used for radiographic evaluation during treatment planning
for implant placement and during surgical procedures to locate optimal implant placement site

Surgical Guides
The dentist will scan the patient
using an intraoral scanner
The same patient will also
take a 3D exposure

Introduction to Digital Dentistry

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