Two Great Tastes that Taste Great Together

Earn
2 CE credits
This course was
written for dentists,
dental hygienists,
and assistants.
Two Great Tastes that Taste
Great Together: Chair Side
CAD/CAM and Cone Beam
Integration in Implantology
A Peer-Reviewed Publication
Written by August de Oliveira DDS
Abstract
Chairside CAD/CAM and cone beam scanners work together to help
make dental implants a safe, predictable, efficient procedure for
patients and dentists. A CAD/CAM optical scan and crown proposal
can aid dentists in many ways. The crown proposal and soft tissue
represented in an optically scanned virtual model can aid the doctor in
the presurgical planning of implants. The virtual hard and soft tissue
model can be combined with a cone beam scan to reduce artifacts
created by radiopaque materials. Optical scans of duplicate dentures
can aid in the planning of edentulous cases. In some cases an intraoral
scan can replace a stone model in the fabrication of a surgical guide.
CEREC® guide is a milled surgical guide that allows dentists to place
implants via guided surgery chairside. With new advances in both
lab and chairside CAD/ CAM systems, dentists now have the ability to
fabricate custom abutments, crowns and frameworks.
Educational Objectives:
At the conclusion of this educational activity
participants will be able to:
1. Discuss the different ways that cone beam
and CAD/CAM interact.
2. Describe the limitations of CBCT scan
without the aid of optical scan data.
3. Describe the benefits of guided implant
surgery with immediate implants.
4. Discuss the relative distances between the
implant, other implants, teeth and bone in
surgical implant placement.
5. Discuss the options available for digitally
manufactured custom abutments, crowns,
substructures and overdenture bars.
Author Profile
August de Oliveira DDS has been involved in CAD/CAM dentistry since
2004 and lectures nationwide. Dr de Oliveira has written two books on
implantology, “Implants Made Easy”, and “Guided Implantology Made
Easy.” He currently practices general dentistry in Encino, CA, is a forum
moderator for Dentaltown.com. Dr de Oliveira can be reached for questions by email at augustdds@gmail.com
Author Disclosure
Dr de Oliveira is a paid speaker for Sirona and Patterson Dental. He
lectures for Sirona and Patterson Dental on CEREC, Galileos and Guided
Implant Surgery. Dr. Oliveira is co-founder of an online magazine of
digital dentistry, DigitalEnamel.com.
Go Green, Go Online to take your course
Publication date: Aug. 2013
Expiration date: July 2016
Supplement to PennWell Publications
PennWell designates this activity for 2 Continuing Educational Credits
Dental Board of California: Provider 4527, course registration number CA# 02-4527-13080
“This course meets the Dental Board of California’s requirements for 2 units of continuing education.”
The PennWell Corporation is designated as an Approved PACE Program Provider by the
Academy of General Dentistry. The formal continuing dental education programs of this
program provider are accepted by the AGD for Fellowship, Mastership and membership
maintenance credit. Approval does not imply acceptance by a state or provincial board of
dentistry or AGD endorsement. The current term of approval extends from (11/1/2011) to
(10/31/2015) Provider ID# 320452.
This educational activity was developed by PennWell’s Dental Group with no commercial support.
This course was written for dentists, dental hygienists and assistants, from novice to skilled.
Educational Methods: This course is a self-instructional journal and web activity.
Provider Disclosure: PennWell does not have a leadership position or a commercial interest in any products or services
discussed or shared in this educational activity nor with the commercial supporter. No manufacturer or third party has had any
input into the development of course content.
Requirements for Successful Completion: To obtain 2 CE credits for this educational activity you must pay the required fee,
review the material, complete the course evaluation and obtain a score of at least 70%.
CE Planner Disclosure: Heather Hodges, CE Coordinator does not have a leadership or commercial interest with products or
services discussed in this educational activity. Heather can be reached at hhodges@pennwell.com
Educational Disclaimer: Completing a single continuing education course does not provide enough information to result
in the participant being an expert in the field related to the course topic. It is a combination of many educational courses and
clinical experience that allows the participant to develop skills and expertise.
Image Authenticity Statement: The images in this educational activity have not been altered.
Scientific Integrity Statement: Information shared in this CE course is developed from clinical research and represents the
most current information available from evidence based dentistry.
Known Benefits and Limitations of the Data: The information presented in this educational activity is derived from the
data and information contained in reference section. The research data is extensive and provides direct benefit to the patient and
improvements in oral health.
Registration: The cost of this CE course is $49.00 for 2 CE credits.
Cancellation/Refund Policy: Any participant who is not 100% satisfied with this course can request a full refund by
contacting PennWell in writing.
Educational Objectives
At the conclusion of this educational activity participants
will be able to:
1. Discuss the different ways that cone beam and CAD/
CAM interact.
2. Describe the limitations of CBCT scan without the aid
of optical scan data.
3. Describe the benefits of guided implant surgery with
immediate implants.
4. Discuss the relative distances between the implant,
other implants, teeth and bone in surgical implant
placement.
5. Discuss the options available for digitally manufactured custom abutments, crowns, substructures and
overdenture bars.
combination of CAD/CAM and CBCT technologies
allow practitioners to truly harness the power of 3D in
implantology (Fig. 1).
Figure 1. By using a chairside CAD/CAM and cone beam scanner,
implants can be planned and fabricated with the final restoration type
and position in mind.
Abstract
Chairside CAD/CAM and cone beam scanners work together to help make dental implants a safe, predictable, efficient procedure for patients and dentists. A CAD/CAM
optical scan and crown proposal can aid dentists in many
ways. The crown proposal and soft tissue represented in
an optically scanned virtual model can aid the doctor in
the presurgical planning of implants. The virtual hard
and soft tissue model can be combined with a cone beam
scan to reduce artifacts created by radiopaque materials.
Optical scans of duplicate dentures can aid in the planning
of edentulous cases. In some cases an intraoral scan can
replace a stone model in the fabrication of a surgical guide.
CEREC® guide is a milled surgical guide that allows dentists to place implants via guided surgery chairside. With
new advances in both lab and chairside CAD/ CAM
systems, dentists now have the ability to fabricate custom
abutments, crowns and frameworks.
Conebeam use in dentistry has gained widespread
acceptance. One can’t throw a rock at any local dental
convention and not hit a booth promoting the use of these
scanners. Utilizing a CBCTscan, a dentist can see things
that were once only visualized either by laying large flaps
or obtaining expensive hospital based CT-scans. Even the
best conebeam scan still lacks information that dentists
need to treat patients in the most safe, predictable, efficient manner. By combining the benefits of CBCT and
chairside CAD/CAM scans, doctors can visualize the final
restoration and soft tissue. These technologies can easily
see anatomic structures we seek to avoid. Dental professionals can now plan abutments in harmony with the final
restoration and contours of the adjacent teeth. Dental professionals can fabricate surgical guides chairside, or send
digital models through the internet for guide fabrication.
After implant integration, chairside or lab based CAD/
CAM systems can be used for crowns, custom abutments,
bridge or hybrid frameworks, and overdenture bars. The
Understanding the process of CAD/CAM and cone
beam integration requires some basic information. In this
course, chairside optical scanners, digital impressioning
systems and milling units are referred to as CAD/CAM.
Some examples of these products include CEREC®, E4D®,
Itero® and 3-Shape®. CBCT stands for Cone Beam Computed Tomography. In essence a radiation source (photon
emitter) rotates around a patient once, the photons are
collected on a sensor which may be a Flat Panel or Image
Intensifier.1 Like conventional 2D imaging, radiopaque
objects appear white and those that are radiolucent appear
in various shades of gray. Unlike a fan beam or spiral CT,
which are typically used in a hospital setting, the CBCT
photon source only rotates around the patient once, resulting in less radiation.1 (Fig. 2). In 2D radiography photons
hit an object at right angles and have the same energy level;
these are known as monochromatic photons. This provides
an image with very little distortion and few artifacts. In
a cone beam scan, photons are emitted in a rotating cone
shape, resulting in some photons hitting an object at right
angles, others hitting at other angles or being slowed down
by radiolucent objects.
This results in various energies of photons, or polychromatic photons. Because of this effect, some CBCT
scans can have artifacts or can be distorted due to metal
or other radiopaque objects. Some cone beam systems
use a process known as MARS (Metal Artifact Reduction
Software), which uses a mathematical formula to reduce
these artifacts. Later, this course will describe how incorporating CAD/CAM optical scans can further reduce
distortion due to polychromatic photons and radiopaque
materials.2
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Figure 2. A CBCT scanner consists of a photon emitter and a sensor
that rotates once around the patient.
Figure 3. The model on the left was made from a scan taken with a
CBCT unit that did not utilize MARS. The image on the right was from a
scan that utilizes MARS
hybrid restoration, with a removable appliance supported
by a bar or with a removable appliance directly attached to
implants.3 Implants are incorporated into bone through a
process known as osseointegration, (Fig. 5).There are many
factors contributing to osseointegration such as the amount
of bone surrounding the implant, how the bone is heated or
how much stress it is subjected to from torque, or disruption of the blood supply. In addition, retaining a band of
attached tissue around the implant can ensure retention of
bone around the implant, gingival health and esthetics.
Furthermore, the design and distribution of the implants and the occlusal forces generated on the final prosthesis can affect the health of the bone and surrounding
soft tissue.4
Figure 5. An implant restoration may be supported by an abutment or
screwed directly into the implant. The implant is incorporated into a
patient’s bone via a process known as osseointegration.
Figure 4. Implants can be used to support single unit crowns or
bridges, to support frameworks for full arch prostheses, bars for overdentures or retain a removable prosthesis via attachments.
A dental implant is most commonly used to replace
a single tooth root to support a crown. Multiple implants
are used to either support a framework and restoration
or to serve as “anchors” to retain a removable prosthesis,
(Fig. 4). A crown may be cemented on an abutment or
screwed directly into an implant. Edentulous patients can
be restored with conventional crowns and bridges, with a
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Implants can be placed either conventionally or guided.
Without guided surgery, a flap is usually laid to visualize
the bone in the edentulous site, (Fig. 6). As the osteotomy
is prepared, multiple x-rays are taken to ensure proper positioning of the instruments and ultimately, the implants.
If the angulation of the drill is not in line with the position
of the final osteotomy, subsequent drills can be redirected
to be back on course.5 With guided surgery we need three
things: A scan of the patient, a model (either digital or
stone), and a way of relating the two. After planning the
implant placement with implant software, information
and model are sent to a surgical guide lab for fabrication.
With a specific set of surgical drills and other instruments
(pilot sleeves, handles, keys, or drill stops), the implant is
placed in the planned location. Because we already know
the limitations of the patient’s anatomy, tissue punches
or smaller flaps can be used, reducing patient discomfort.
Furthermore, because the implant has been planned in
advance, the surgery is shorter since there is no need to
change the angulation of the osteotomy and no need for
radiographic confirmation, (Fig. 7).6
3
Figure 6. In conventional implantology, a flap is usually laid to visualize the bone and multiple x-rays are taken throughout the procedure
to ensure that the final implant is placed in the proper position.
Figure 7. With guided surgery, large flaps are not usually needed for
visualization as the anatomy has already been explored in the scan.
Punches or smaller flaps can be used. In this case an implant drill is
used with a pilot sleeve.
made up of multiple images that can be “sliced” to allow
visualization within the bone. The implant planning software is typically made up of 5 windows, (Fig. 8). The 3D
panoramic is similar to a 2D pan and is used to navigate
around the patient and to initially place implants. This image should not be used to fine tune implant position. The
axial view shows the occlusal aspect of the patient. The
tangential image is similar to a PA radiograph, showing
a mesio-distal view, with the exception that angulation of
the slices can be corrected with an adjustment lever. The
cross sectional view displays the buccal-lingual aspect of
the patient.7 The American Academy of Oral and Maxillofacial Radiology (AAOMR) released a position paper
stating that this view is very important in the success of
placing implants. The cross sectional view provides the
most accurate assessment of the size and length of the implant to be placed. (Fig. 9).8 Finally, the 3D model allows
the doctor to see how the implants relate to the arch and
the jaw, (Fig. 10).
Figure 9. The cross sectional view provides the best view for determining the buccolingual thickness of bone as well as the relationship of
the implant platform to the crest of the alveolar ridge.
Figure 8: Most implant programs consists of 5 screens: 3D Panoramic,
Axial, Tangential, Cross Sectional, and the 3D Model.
Figure 10. The 3D model best shows how implants relate to each other
and the patient’s jaws.
Using the implant planning software is quite easy. Some
CBCT systems incorporate scanning software along with
an implant planning module. In other systems, CBCT
data needs to be either converted to 3D or exported out of
the native CBCT software and imported into stand alone
implant software in DICOM format. Any CBCT study is
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The 3D model, also known as the 3D rendering is, in
the author’s opinion, one of the most important views in
any CBCT implant planning software. The major limitation of all CBCT machines is that they have excellent clarity for bone and the roots of teeth, but lack clarity when it
comes to displaying teeth with restorations or the overlying
soft tissue. When planning implants, a balance must be
struck between placing the implant in harmony with the
roots of the adjacent teeth, yet planning the position of the
future abutment or implant platform in the proper relation
to the CEJ and contact positions of the neighboring clinical crowns. If the adjacent teeth are distorted in the scan
due to metal scatter, one cannot predictably place implants
supporting a restoration mirroring those contours. Many
implant programs have multiple rendering patterns such as
Volumetric Mode, Volumetric Mode with Contours, and
Surface Mode. Although in Volumetric Mode with Contours, the soft tissue outline can be visualized, there is not
enough information to adequately predict the contours of
the tissue surrounding the future implant, (Fig. 11). CAD/
CAM scans provide the missing link in visualizing soft
tissue with extreme clarity, and the contours of teeth even
with dense radiopaque material, (Fig. 12).
Figure 11. In Volumetric Mode With Contours, the soft tissue can be better visualized, however it is never clear enough to adequately predict the
relationship of the gingiva to the future implant.
Figure 13. In this example, a chairside CAD/CAM scan is used to
obtain a crown proposal for an immediate molar implant. This data is
imported into the implant software so a surgical guide can be milled
chairside.
CAD/CAM optical scans can be used with a CBCT
scan five ways. A simple crown form or scanned wax up
and virtual model can be used to place the implant in the
proper restorative position, (Figs. 13 and 14).The virtual
model can be used instead of displaying the coronal portions of teeth, reducing noise. Duplicates of the patient’s
dentures or radiographic guides can be scanned, showing
the user the proper location of teeth and extent of the
denture flange. In the case of a guide fabricated from a virtual model, this eliminates the need for a physical model.
CAD/CAM works interchangeably with CBCT scans in
the planning and production of a CEREC® guide. Both lab
and clinic based CAD/CAM systems can be used to not
only fabricate a chairside cemented implant crown, but
a host of restorations ranging from simple custom abutments to hybrid frameworks and overdenture bars.
Figure 14. A mounted diagnostic wax up can be incorporated directly
into implant software with minimal design effort.
Figure 12. In this example distortion is present with the metal
artifacts. The CAD/CAM model and proposal allow the user to see the
adjacent teeth form and gingival anatomy clearly.
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Figure 15. Although using Barium Sulfate containing denture teeth in
a scan does provide clues to the final restorative position, there is no
way of determining soft tissue depth. With a CAD/ CAM optical scan,
one can toggle off the restoration to provide improved visualization of
the edentulous ridge and gingiva.
The term “Crown Down Implantology” is almost cliche presently. More and more dentists are addressing the
surgical aspect of implantology as a response to implants
that have been placed in unrestorable positions. By using
barium sulfate teeth in a scan, one can get a good idea of
where the crown will eventually be, but there are two major drawbacks to this method. First, this involves an extra
appointment and additional cost to obtain a radiographic
guide containing barium sulfate teeth. Secondly, there
is no information regarding the patient’s soft tissue. By
obtaining an optical scan the CBCT user has not only a
crown form that can be toggled off and on, but a crystal
clear representation of the teeth and gingiva, (Fig.15). This
“yellow” model allows the user to plan for the height of
the soft tissue, and clearly see the adjacent teeth contours
which allows one to plan “by the numbers”.
There are a few numeric variables that are necessary
in implant planning. A CAD/CAM model and proposal
provides the greatest case planning accuracy. An implant
should be no closer to the adjacent teeth than 1.5mm. Individual implants should be no closer to each other than
3mm, (Fig.16). The implant top or platform, should be on
average, 3-4mm apical to the CEJs of the adjacent teeth.
Figure 16. When planning implants in the software, distances can be
measured. An implant should be no closer to an adjacent tooth than
1.5mm and no closer to an adjacent implant than 3mm. The implant
should have at least 1.8mm of bone on the buccal and lingual.
The platform should be 5mm or less to the most apical
extent of the adjacent teeth contacts, (Fig. 17). The implant
itself should be smaller in diameter than the root it is replacing, 2mm below the CEJ of the adjacent teeth.9 In all
restorations, the implant abutment should be centered mesiodistally, eliminating the presence of cantilevers. In the
anterior, if using a screw retained restoration, the center of
the implant and the screw access should be centered in the
cingulum. In the posterior, ideally it should be in the central fissure, (Fig. 18). When planning a hybrid restoration
or overdenture bar, 11-14mm of space is required between
the bone of the ridge and the occlusal or incisal surfaces of
the opposing teeth, (Fig. 19).10 These numbers are easily
measured with an optical model and proposal.10 Without,
inaccuracy can easily occur.
Figure 17. For proper esthetics and emergence profile in the final
restoration, the implant platform should be 3-4mm apical to the CEJ
of the adjacent teeth. To achieve interdental papilla formation, the
platform should be placed no deeper than 5mm to the most gingival
aspect of the adjacent teeth contacts.
Figure 18. For a screw retained implant crown, the screw access should
be in the cingulum for anterior teeth and the center of the occlusal
table for posterior teeth.
Figure 19. An overdenture bar may require up to 14mm of space between the bone and the opposing teeth to allow for the bar itself and
the attachments and denture.
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Even though some CBCTs have metal artifact reduction
software, there still may be some distortion due to radiopaque
material in the patient’s mouth. Without the aid of the optical data from CAD/CAM, it can be difficult to adequately
predict the shape of the future crown while planning the
implant position. By using a process known as “clipping”,
distorted portions of teeth in the 3D CBCT model can be
cut away and replaced with the clear optical data from a
CAD/CAM scanner. With this technique we truly get the
best of both worlds. CBCT scans are great for visualizing
bone, teeth roots and underlying anatomic structures. Optical scans are great for visualizing the teeth and gingiva, (Fig.
20). The CAD/ CAM model and proposal can be easily
toggled off or on to show the underlying scan. When planning an implant, it is beneficial to first spend time making
sure the implant is in the correct position mesiodistally and
buccolingually in the bone and away from nerves, sinuses
or the floor of the nose, only using the CBCT scan. After
the position is achieved, the CAD/CAM crown proposals
can be toggled back on. The final abutment position and its
relationship to the adjacent teeth contacts is addressed by
rotating the platform of the implant, while leaving the apex
stationary, (Fig. 21).
There is nothing more critical to the success of an
edentulous case than the pre-surgical planning. There are
many variables that go into an edentulous case such as
whether the prosthetics will be fixed or removable, and if
removable, what types of attachments are needed and their
ultimate position in the bar. In the surgical placement of
implants, there are no teeth to stabilize the guide. Stabilization pins are used to fix the guide in a stable reproducible
position. These pins need to be placed in a tripod pattern
and be contained within the flanges of the surgical guide.
If the prosthesis is fixed, the amount of interocclusal clearance will determine the type of restoration.
Figure 22. The image on the left shows a plan for a mandibular
hybrid restoration without consideration of the proper position of
the future teeth or stabilization pins used in surgery. The case on the
right shows the value of the optical scan data, aiding in pin positions
within the flange of the denture (and future guide) as well as the
proper distribution of implants within a hybrid restoration.
Figure 20. Due to the large amount of metal restorations in this patient’s mouth coupled with the fact that the patient had a mild tremor,
it was difficult to get a scan acceptable for implant planning. However,
after applying the CAD/CAM data it’s easy to see where the implant
should be placed for an ideal final restoration.
Figure 21. In this case two implants were planned for a surgical guide
. Within the implant software there is a function known as “toggling”
in which one can turn off either the restorations or the yellow virtual
model. Its important to look at the implant and its relationship to the
adjacent teeth to have a holistic view as to how the implants fit in the
arch, The crown forms can then be toggled back on and the future abutments or screw position adjusted.
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A hybrid requires at least 11mm of occlusal clearance,
while conventional screw retained crowns and bridges
only need 6-7mm. In a hybrid prosthesis, the anterior
screw access holes have to be lingual to the incisal edges
of the denture teeth, while the posterior screw access holes
should emerge from the occlusal table, (Fig. 22). If the case
is removable, up to 15mm of clearance is required when an
underlying bar is used. One also needs to know the amount
of cantilever posterior to the most distal implants. The A-P
spread is the distance between the most anterior and most
posterior implants bilaterally. A bar or fixed prosthesis
can be cantilevered 1.5 times the AP spread.12 Promising
a patient a fixed restoration but not having enough A-P
distance to deliver it is a customer service disaster, but having a CAD/CAM overlay can easily help one predict this,
(Fig. 23, 24).
One criticism of undertaking guided implant cases, is
the time to get the surgical guide back from the lab. There
can also be distortion when taking full arch impressions
without a custom tray. It is inefficient and frustrating to
spend time and money obtaining a radiographic and/
or surgical guide, set up a room for surgery, block out
productive time in your schedule and have a guide not
fit. With some surgical guides fabricated from a virtual
model, there are no required physical impressions.
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Figure 23. The concept of the AP-Spread is critical in deciding whether
a prosthesis can be fixed or removable. If one measures the distance
from the most anterior implants to the most posterior implants, a
restoration can be made that is 1.5 times this dimension. If the AP
distance is 10mm, a 5mm cantilever can be safely achieved in either a
fixed or bar situation.
guide fabrication. Furthermore, CEREC® guide allows for
a great deal of accuracy and stability in placing immediate
implants, (Fig 26).
Figure 25. Optical scans can be taken in the mouth, if there are time
constraints. If the doctor wants a physical model, impressions can be
taken and the model scanned extraorally with a CAD/CAM scanner.
Figure 24. A hybrid restoration consists of a metal framework that is
attached to implants with screws. The placement of the implants is
critical as the screw holes cannot be placed buccally for the sake of
esthetics.
Figure 26. CEREC® guide allows dentists to fabricate accurate surgical
guides chairside. The reference body is milled in CEREC. The reference
body makes an indentation that the drill body occupies. The reference
body also contains markers known as fiducials that helps the implant
software relate the implant to the patient’s jaw.
The patient’s full arch is scanned optically via CAD/
CAM, imported into the implant software and uploaded
to a lab after the implant has been planned. A very accurate guide can be fabricated and returned to your office in
approximately 6 working days with no physical model. If
the clincian does not own a chairside scanner or does not
wish to scan the arch, a model can be taken and sent to
the lab. The model can also be poured in CAD stone, then
scanned optically if desired, (Fig 25).
One of the greatest advances in guided implantology,
in this authors opinion, is CEREC® guide. CEREC® guide
is the only chairside milled CBCT-based surgical guide
system at the present time. A criticism of guided surgery
is the expense of obtaining a laboratory fabricated surgical guide. CEREC® guide allows the dentist to mill the
surgical guide chairside for approximately $60 per guide.
Fewer office visits may also be required with chairside
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Figure 27. Three items are needed to fabricate a CEREC® guide.
Thermosplastic tray material, a CEREC® guide block set, and a set of
Sirona® keys specific to the implant and drill system being used.
Figure 28. When planning a CEREC® guide, plan the implant first, then
toggle on the restoration to fine tune, then locate the reference body.
Figure 29. After the drill bodies have been milled they are placed into
the thermoplast in the indentations made by the reference bodies.
Specific Sirona keys are used to guide the implant drills.
Three things are needed to fabricate a CEREC® guide.
Thermoplastic tray material, a CEREC® guide block set,
and a set of keys made by Sirona® for the implant drill
system used, (Fig. 27) An alginate impression is taken of
the teeth surrounding the edentulous space. The model can
be poured in stone, or a polyvinyl die material. The thermoplastic material is heated in boiling water and shaped
around the edentulous space and surrounding teeth. A part
known as the reference body does two things. It makes an
indentation into the tray material. CEREC guide will make
a drill body which is placed into this form. The second use
of the reference body is that it has glass beads known as
fiducial markers that aid in locating the implant in three
dimensional space. The patient is scanned wearing the tray
and reference body in the CBCT machine, (Fig 28).
CEREC® data can be imported into the scan to aid in
planning the implant with a crown form. Once the implant
has been properly planned and CEREC® guide is selected
as the sleeve system, the reference body is then located in
the software. After the software recognizes the reference
body, coordinates can be exported into CEREC® and the
drill body milled out, (Fig. 29). The drill body is milled in
the MC XL milling unit with specific acrylic blocks. After
the part is milled and the sprue removed, a hole is made in
the location of the edentulous space on the thermoplastic
material and the drill body replaces the reference body.
The CEREC® guide is cold sterilized and can then be used
for surgery. Utilizing a key system specific to the implant
drill kit used, the dentists can drill the osteotomy and place
the implant accurately, (Fig. 29).
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Patients are living longer and outliving their teeth, (Fig.
30). Especially in the anterior, thin endodontically treated
teeth typically fracture at or below the gumline. Crown lengthening, retreatment of the root canal, and a new post and core
and crown may cost the same as implant and final prosthesis
which typically have a higher long term success rate. Immediate implants in the anterior and molar sites are extremely difficult to do non-guided. First, a tooth is removed and the socket
curretted and irrigated. Due to the sloping nature of most root
sockets, a purchase is made 1/3 of the way coronal to the apex
of the socket with a sharp bur. Next, the initial implant drill
(pilot) engages the purchase, yet needs to be rotated to direct
the osteotomy away from the buccal plate. The implant must
be planned with the apex at least 3mm apical to the socket, yet
the platform of the implant must be placed 1-2mm subcrestal
to the extraction socket. At the same time the implant cannot
touch the buccal or lingual plates, yet can engage the mesial
and distal walls of the socket for stability.12 All of this is very
hard to do without a guide, however with a surgical guide
the procedure feels almost as easy as a conventional guided
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case, (Fig. 31). In the case of an immediate molar implant,
the osteotomy needs to be centered into the furcal bone.
Without a guide there is a tendency to drift into mesial or
distal root sockets.13 Using a technique of leaving the tooth
roots in the bone until after the pilot drill is used and using
CEREC® guide to keep subsequent drills stable without
the teeth roots, molar immediates become very easy and
very predictable, (Fig. 32).
Figure 30. CEREC ® guide allows dentists to place immediate implants
just as predictably as conventional implants. In this case #8 had a
horizontal fracture mid root, the remaining tooth was extracted and
the implant was placed with the aid of CEREC® guide. The final restoration shows proper contours of the surrounding soft tissue.
Figure 31. Steps in placing an immediate implant, non guided. A:
Extract tooth curette socket. B: Make purchase with a sharp bur at an
angle. C: Straighten out osteotomy with pilot drill. D: Place implant at
least 3mm past the apex of the socket while not touching the buccal
and lingual plates of bone with the platform at least 1-2mm sub
subcrestal.
Figure 32. In the case of a molar immediate implant, the osteotomy
must be centered in the furcal bone. CEREC® guide allows the dentist to
keep the implant drills well centered.
Patients do not come to the dental office for implants, they come for teeth! With improvements in
CAD/CAM systems and new options for blocks, users
can now fabricate custom abutments and screw retained
crowns chairside. In some cases, after the implant is
integrated, a stock zirconia or titanium abutment can be
used and a crown fabricated chairside with CAD/CAM
and cemented, (Fig. 33). However, there are indications
for the use of a custom abutment or a screw retained
restoration. A custom abutment is used to correct angulation, to achieve a more hygienic cement line, and
to aid in providing an anatomically correct emergence
profile in the final restoration.14 Custom abutments can
be made out of solid titanium or zirconia on a titanium
base, (Fig. 34).
In the near future, manufacturers will provide a
lithium disilicate block that will also be cemented on
a titanium base. To fabricate a custom abutment or
a screw retained implant crown, a Ti-base kit is used
by screwing the titanium base either into the implant
itself or on an implant analog on a model. A white scan
body cap is placed on the base and scanned with either
a chairside oral scanner or a lab based model scanner.
In CAD/CAM software, the scan body is located and
the restoration is either planned as a one piece screw
retained crown, or a two piece crown and custom abutment. The restoration can then be milled chairside or
sent to a lab to be milled and sintered if needed, (Fig.
35). CAD/CAM connected labs will soon be able to
mill not only abutments and bridge frameworks in
titanium and zirconia, but bars for overdentures and
frameworks for hybrids from scans taken chairside,
(Fig 36 and 37).
CAD/CAM and cone beam work together to increase
the safety, efficiency, and predictability of implants and
the final restorations. Beginning with diagnosis, the
combination of technologies allow doctors to see more
and predict the planned outcome of implants. Through
the use of various guides, practitioners can place implants in harmony with the underlying anatomy and the
adjacent teeth contours.
It is very rewarding to take an edentulous patient
from a removable to a fixed appliance. Yet full arch implant placement and restoration can be very problematic
if the proper placement and number of implants cannot
be obtained. By completing edentulous cases guided,
doctors can place and restore implants with the final restoration in mind down to screw position or attachment
type. In our current times, being able to achieve “same
day dentistry” has been elusive in guided implantology
until the advent of the CEREC® guide system. CEREC®
guide allows dentists to place implants in conventional
and immediate situations with a great deal of ease and
accuracy.
10www.ineedce.com
Figure 33. If the placement of the implant in the available bone is
ideal and the tooth root is cylindrical in shape, a stock titanium or
zirconia abutment can be used and a CAD/CAM crown milled chairside.
Figure 36. Labs can offer one piece milled titanium abutments for
strength, for use with PFM or gold restorations.
Figure 37. In the near future labs will also be able to provide custom
titanium and zirconia bars and frameworks for edentulous cases from
intraoral scans.
Figure 34. With new developments in CAD/ CAM systems dentists will be
able to mill custom abutments and screw retained implant crowns.
By using chairside or lab based CAD/CAM systems,
practitioners can give their patients implant restorations that
look like teeth. Larger cases or custom zirconia or titanium
abutments and frameworks can be sent to labs to be processed. It boggles the mind what we can achieve currently, or
what will be possible in the future utilizing these technologies.
Figure 35. Implants can now be scanned intraorally using scan bodies. Custom abutments and crowns can be milled chairside or sent
to a lab for milling and sintering if needed. Note, the black lines on
the abutments are used for orientation and were removed prior to
cementation. Abutments were fabricated with a Ti-base kit and Zirconia
Block. Crowns were milled in a chairside CAD/CAM system using a low
translucency lithium disilicate block.
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Bibliography
1. Miles, Dale A., “Color Atlas of Cone Beam Volumetric
Imaging For Dental Applications”. pg 2:13. Hanover
Park, IL 2008 Quintessence Publishing.
2. Bechara BB et al. “Metal artifact reduction with cone
beam CT: an in vitro study”. Dentomaxillofac Radiol.
2012 Mar;41(3):248-53. doi: 10.1259/dmfr/80899839.
Epub 2012 Jan 12.
3. Jacobs, Stuart H et al. “Dental Implant Restoration:
Principles and Procedures”. pg 4-5. Suurey, UK. 2011.
Quintessence Publishing.
4. Adell et al.”A 15 year study of osseointegrated implants
in the treatment of the edentulous jaw”. International
Journal of Oral Surgery. 1981. 10(6) pg 387-415.
5. Block, Michael S. “Color Atlas of Dental Implant Surgery:
2nd Edition”. pg 4-13. St. Louis Missouri. 2007. Elsevier
Publishing.
11
6. Tardieu, Phillipe B. et al. “The Art of Computer
Guided Implantology”. pg 2-3. Hanover Park, Il. 2009.
Quintessence Publishing.
7. Zoller, Joachim, et al. “Cone-beam Volumteric Imaging in
Dental, Oral and Maxillofacial Medicine: Fundamentals,
Diagnostics, and Treatment Planning. pg 17-22. Berlin.
2008. Quintessence Publishing.
8. Tyndall DA et al “Position statement of the American
Academy of Oral and Maxillofacial Radiology on
selection criteria for the use of radiology in dental
implantology with emphasis on cone beam computed
tomography”. Oral Surg Oral Med Oral Pathol Oral
Radiol. 2012 Jun;113(6):817-26. doi: 10.1016/j.oooo.
2012.03.005.
9. Misch, Carle E. “Contemporary Implant Dentistry:
Third Edition”. pg 157-158. Canada 2008. Elsevier.
10.Shafie, Hamid R. “Clinical and Laboratory Manual
of Implant Overdentures”. pg 63-76. Ames, IA 2007.
Blackwell Publishing.
11.Misch, Carl E. “Dental Implant Prosthetics”. pg 43-52.
China. 2005. Elsevier.
12.de Carvalho, BC et al. “Flapless single-tooth immediate
implant placement”. Int J Oral Maxillofac Implants. 2013
May-Jun;28(3):783-9. doi: 10.11607/jomi.2140.
13.Tarnow, DP. “Classification of molar extraction sites for
immediate dental implant placement: technical note”. Int
J Oral Maxillofac Implants. 2013 May-Jun;28(3):911-6.
doi: 10.11607/jomi.2627.
14.Drago, Carl. “Implant Restorations: A step by Step
Guide”. pg 18-23. Ames, IA 2007. Blackwell Publishing.
Author Profile
August de Oliveira DDS has been involved
in CAD/CAM dentistry since 2004 and lectures nationwide. Dr de Oliveira has written
two books on implantology, “Implants Made
Easy”, and “Guided Implantology Made
Easy.” He currently practices general dentistry in Encino, CA,
is a forum moderator for Dentaltown.com. Dr de Oliveira can be
reached for questions by email at augustdds@gmail.com
Author Disclosure
Dr de Oliveira is a paid speaker for Sirona and Patterson Dental.
He lectures for Sirona and Patterson Dental on CEREC, Galileos
and Guided Implant Surgery. Dr. Oliveira is co-founder of an
online magazine of digital dentistry, DigitalEnamel.com.
Notes
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Online Completion
Use this page to review the questions and answers. Return to www.ineedce.com and sign in. If you have not previously purchased the program select it from the “Online Courses” listing and complete the
online purchase. Once purchased the exam will be added to your Archives page where a Take Exam link will be provided. Click on the “Take Exam” link, complete all the program questions and submit your
answers. An immediate grade report will be provided and upon receiving a passing grade your “Verification Form” will be provided immediately for viewing and/or printing. Verification Forms can be viewed
and/or printed anytime in the future by returning to the site, sign in and return to your Archives Page.
Questions
1.In a CBCT scan how many times does the
photon emitter rotate around the patient?
11. What are the correct names of the 5 windows
in most implant software?
2.Hospital based CT scanners are known as a:
12. What can you NOT see in the cross
sectional?
a.once
b.twice
c. three times
d.never
a. Fan Beam CT
b. Spiral Centrifuge
c.MRSA
d.Ultrasound
3.In 2D Radiology such as a bitewing, photons
emitted from an xray tube are:
a.polymorphic
b.monozygotic
c.ectomorphic
d.monochromatic
4.MARS in CBCT imaging software stands
for:
a.
b.
c.
d.
Metal Artifact Reduction Software
Metal Article Refraction Source
Middle Atlantic Roetogen Society
None of the above
5.What is an implant NOT used for?
a.
b.
c.
d.
Supporting a screw retained crown
Supporting an abutment and cemented restoration
Supporting a hybrid framework or overdenture bar
Supporting an inlay or onlay
6.What is NOT a factor in osseointegration or
maintaing bone around an implant?
a.
b.
c.
d.
Torque on implant insertion
Heating of the bone in osteotomy preparation
Distribution and occlusal forces of the final restoration
Eating a gluten free diet
7.Which three things are needed to obtain a
CBCT generated surgical guide?
a. A CBCT scan, a virtual or physical model of the
patient’s teeth, and a way of relating the two.
b. A CBCT scan, a facebow, and a fully adjustable
articulator.
c. A physical or virtual model, a panoramic x-ray, positive
thinking.
d. A CBCT scan, a diagnostic wax up, catgut sutures
8.Which is NOT used to guide drills in guided
surgery?
a.Half-hollenbecks
b.Keys
c. Pilot sleeves
d.Handles
9.Which of the following statements is true:
a. Larger flaps are required in guided surgery to view
anatomy.
b. More time is typically needed in guided surgery than
conventional implant placement.
c. More pain is usually associated with guided surgery due
to small flaps or punches.
d. Smaller flaps or punches can be used in guided surgery
if the patient has a favorable amount of attached tissue.
10. Which of the following statements are not
true?
a. Some implant software requires the user to export
DICOM files out of the native CBCT imaging
software.
b. Other programs may require conversion to a 3D format.
c. Some implant software combines the CBCT imaging
software as well as implant planning and guide generating software.
d. CBCT scans require the user to have a pay-per-implant
dongle attached to the acquisition PC.
a.
b.
c.
d.
a.
b.
c.
d.
Analog, Digital, Teliomere, Axel, Beaker
Panoramic, Tangential, Cross Sectional, Axial, 3D
Tesseract, Skynet, Nolcorp, Cyberdine, Galactica
Panorama, Triaxis, Cross Conventional, 4D, Axlical
The buccal plate of bone
The lingual plate of bone
The proper bucco-lingual size of implant to be used
The tongue
13. Which of the following is false regarding the
5 windows in their mplant software?
a. The Tangential is a good view for determining the
mesio-distal diameter of the edentulous space.
b. The 3D view shows the planned implants in relation to
the jaws.
c. The Axial shows and occlusal view of the sliced CBCT
scan.
d. The 3D panoramic is the best view ever for fine tuning
implant placement.
14. The AAOMR’s position paper stated:
a. The Cross Sectional view in a CBCT viewer is helpful
in planning dental implants.
b. The Axial view in a CBCT viewer is helpful in planning
dental implants.
c. The Tangential view in a CBCT viewer is helpful in
planning dental implants.
d. The 3D panoramic in a CBCT viewer is helpful in
planning dental implants.
15. Which of the following windows does the
author feel is the most important in implant
planning?
a.
b.
c.
d.
The 3D Rendering
The Panoramic
The Axial
The Tangential.
16. What is the major limitation in CBCT scans
when it comes to implant planning?
a. CBCT is great for soft tissue not hard tissue
b. CBCT cannot visualize soft tissue predictably or tooth
contours in the presence of dense radio opaque material.
c. Nothing, CBCT is awesome.
d. CBCT is better for visualizing metal than enamel or
dentin.
17. Which is the best view for estimating the
Mesio-Distal length of the edentulous space?
a.Tangential
b.Axial
c. 3D Panoramic
d. Cross Sectional
18. Which is NOT a rendering mode in the 3D
window in implant software?
a.
b.
c.
d.
Volumetric Mode
Volumetric Mode with Contours
Surface Mode
God Mode
21. In order to obtain good soft tissue formation
around implants which is the greatest
dimension between the implant platform and
the most gingival aspect of the inter dental
contact point?
a.12mm
b.30mm
c.5mm
d.15mm
22. In an anterior tooth implant crown, where
should the screw access hole be located?
a.
b.
c.
d.
On the buccal surface for access.
In the incisal edge for esthetics.
At right angles to the mammelons.
In the cingulum.
23. Which if the following statements are true?
a.
b.
c.
d.
Stabilization pins should be placed in the palate.
Stabilization pins should be contained within the flange.
Stabilization pins are never needed for edentulous cases.
Stabilization pins osseointegrate within hours.
24. How long can a bar be as compared to the
AP spread?
a.
b.
c.
d.
1 X AP
2 X AP
6 X AP
1.5 X AP
25. Which if the following is false regarding the
guides made from a virtual model?
a. One can scan with CAD/CAM intra orally to obtain a
model.
b. One can scan a stone model.
c. One can mail a stone model to Sicat.
d. CAD/CAM systems mill out the entire guide in 16
minutes.
26. What three things are needed to use
CEREC guide?
a. A porcelain block, a size 16 bur, and a redcam.
b. Thermoplastic material, CEREC block set, Sirona key
set.
c. Aluminum Oxide Powder, scanning liquid, Gel Foam.
d. Isolite, Invisalign, Iodoform gauze.
27. Which is not a step in osteotomy preparation
in immediate implants?
a.
b.
c.
d.
Extract remaining tooth or roots.
Make purchase in socket with sharp bur or drill.
Lateralize the mandibular nerve.
Extend the osteotomy at least 3mm past the root apex.
28. In the case of a molar immediate, where
should the osteotomy be centered?
a.
b.
c.
d.
In the cingulum.
In the mesial root.
In the distal root.
In the furcal bone.
19. Which is NOT a benefit of CAD/CAM and
CBCT integration?
29. What can most labs NOT do?
20. Which is the proper distance between
implants?
30. Which of the following statements are false
regarding custom abutments?
a. Importing a crown form or waxup.
b. Removing metal artifacts through a process known as
“clipping”.
c. Fabrication of a CEREC guide.
d. 3D printing of STL models.
a..5mm
b.1mm
c.1.5mm
d.3mm
a.
b.
c.
d.
a.
b.
c.
d.
Mill zirconia abutments
Mill titanium abutments
Mill hybrid frameworks
Mill implants.
Can be used to correct angulation.
Can be used to move the cement line more coronal.
Can aid in achieving a proper emergence profile.
Negate the use of cement.
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ANSWER SHEET
Two Great Tastes that Taste Great Together: Chair Side CAD/CAM and Cone Beam
Integration in Implantology
Name:
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Requirements for successful completion of the course and to obtain dental continuing education credits: 1) Read the entire course. 2) Complete all information
above. 3) Complete answer sheets in either pen or pencil. 4) Mark only one answer for each question. 5) A score of 70% on this test will earn you 2 CE credits.
6) Complete the Course Evaluation below. 7) Make check payable to PennWell Corp. For Questions Call 216.398.7822
If not taking online, mail completed answer sheet to
Educational Objectives
Academy of Dental Therapeutics and Stomatology,
1. Discuss the different ways that cone beam and CAD/CAM interact.
A Division of PennWell Corp.
P.O. Box 116, Chesterland, OH 44026
or fax to: (440) 845-3447
2. Describe the limitations of CBCT scan without the aid of optical scan data.
3. Describe the benefits of guided implant surgery with immediate implants.
4. Discuss the relative distances between the implant, other implants, teeth and bone in surgical implant placement.
5. Discuss the options available for digitally manufactured custom abutments, crowns, substructures and overdenture bars.
Course Evaluation
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