• The images can be produced on the radiographic film, photographic
paper in book form or on the computer monitor.
• Used in planning complex cases such as full arch maxillary
• Patient requiring complex procedures such as sinus lift or nerve
• To assess the bone quality and quantity
• Determination of the bone density
• Useful in scanning the premaxilla without overlapping of the
• It gives an accurate assessment of the bone quality and quantity in
• Overlapping of images is not there.
• Direct measurements can be made on the cross-sectional image
using the digital millimetre ruler or caliper.
• Radiation dosage is high and the scan should be only limited to the
• Harmful to the radiosensitive tissues such as eye.
• Artefacts from the metallic restorations produce the scatter-like
These are recently introduced tomographic devices which are capable
of generating high-quality sectional images.
• It uses complex broad beam spiral tomography and is able to scan in
• The scans are dependent on the accurate positioning of the patient
and the experience of the clinician.
• The tomographic sections are 2–4 mm thick.
• The overall radiation exposure is less than the CT scan.
• Although the amount of detailed information is less than a CT, it is
sufficient for the routine procedures.
• To facilitate treatment planning, the overlay virtual implants can be
superimposed on the scan to reveal angulation and the positioning
scanner produces a cone-shaped radiographic beam which exposes a
series of planar images to form a three-dimensional image which can
be visualized according to the need of the clinician.
• The primary benefit of CBCT is that a three-dimensional image of
the osseous area of interest can be constructed and viewed in
• Radiographic exposure is less as compared to CT scans.
• Treatment planning using CBCT leads to reasonable level of
• Motion-related artefacts cause blurring of images.
• In CBCT, metallic restorations cause streak artefacts in all directions.
Guidelines for prescribing CBCT imaging in dental
• To evaluate morphology of residual alveolar ridge
• To determine orientation of alveolar ridge
• To identify anatomic feature that can limit implant placement
• To evaluate pathologic conditions that would restrict implant
• To match imaging findings with that of the restorative plan
• In cases where hard tissue grafting is required
• To evaluate hard tissues after augmentation procedures
Role of radiographic stent in treatment planning in
Radiographic stent has become an important tool in treatment
planning in implant dentistry in recent times. A stent helps in
assessing the position and the angulation of the implant in relation to
the final prosthesis planned by the clinician.
• A radiographic stent mimicking the final restoration is constructed
using the radiographic markers such as gutta-percha or metal
markers which are placed at the proposed position and angulation
• If the patient is a denture wearer, either the denture is duplicated
with acrylic resin having radiographic marker in it or the markers
are placed in the occlusal or palatal surface of the teeth.
• Alternatively, the labial surface of the stent can be painted with a
radio-opaque varnish in order to evaluate the relation of the bone
ridge to the proposed final restoration.
• The radiographic marker should be chosen such that it should not
• Metal markers should not be used during CT scan, as these can
produce scattering on the image.
• Radiographic stents can also be made by placing the radiographic
marker such as ball bearings of various diameters into the wax rim
over the base plate to determine the mesiodistal location.
• Radiographic stents also help to stabilize the jaws, especially in
edentulous patient, during the procedure of the scan.
• The stents are useful during the surgical placement of the implants.
• It helps the clinician to decide on the optimum location, number and
Bone density—a key determinant for treatment
The density of the available bone in the edentulous area greatly
influences the treatment planning of the implant. The success of the
implant depends on the quality of the bone. Good quality bone
assures good primary stability during the placement of the implant.
The bone density is grossly determined using radiographic aid such as
computed tomographs. The thickness of the cortical plate and the
density of the trabecular pattern are best determined during the
Bone can be classified on the basis of macroscopic density into the
3. Coarse trabecular bone (D3)
FIGURE 33-4 Bone quality classification.
• It consists of dense cortical bone.
• It is mostly found in resorbed anterior mandible, thick lateral
aspects of the anterior mandible.
• It can provide excellent stability to the implant prosthesis.
• This type of bone is highly mineralized and is capable of bearing
• D1 bone has limited blood supply and is dependent on the
Dense to thick porous compact and coarse
• It is a combination of dense to porous compact bone on the outside
and the coarse trabecular bone in the inside.
• It is commonly found in the anterior and posterior mandible and
occasionally in the anterior maxilla.
• It provides excellent healing and predictable osseointegration.
• It has an excellent blood supply.
• It has good primary stability during implant placement.
• Healing period of 4 months is recommended.
Porous compact and fine trabecular bone (D3)
• It is composed of thin porous compact bone and fine trabecular
• It is found in the anterior or posterior maxilla and posterior
• Osteotomy can be done rapidly.
• This type of bone has excellent blood supply.
• A hydroxyapatite coated implant is recommended to enhance the
bone contact and accelerate bone healing.
• For threaded implant, high torque handpiece is required to insert
the self-tapping threaded implants.
• Healing period of 6 months is recommended.
• Progressive gradual loading is recommended.
• It has very light density with little or no cortical bone.
• It is found in the posterior maxilla.
• Its primary stability during implant placement is limited.
• Osteotomy should be done with drills narrower than the proposed
• Press fit implants are recommended.
• Sinus elevation and subantral augmentation procedures are advised
to increase the surface area of support.
• Additional implants and progressive loading is recommended.
• Healing period of 8 months is suggested (Table 33-2).
RECOMMENDED MINIMUM HEALING PERIOD
Location Minimum Healing Period
Types of implant restorations are:
1. Single-tooth implant restorations
2. Implant-supported overdentures
3. Multiple fixed implant restoration
Single-tooth implant restorations
Single-tooth implant restorations are those restorations which are not
connected to other teeth and to adjacent implant.
• These are similar to conventional single crown.
• These single crowns are cemented or screw retained on
prefabricated or customized abutment.
• Cantilevering to the single crown should be avoided.
• If more than two teeth are missing, the edentulous space can be
restored with individual implant-retained crowns or a fixed bridge.
• Higher success rate is reported in single implant cases.
• When replacing posterior teeth with the implant-supported
restoration, wider diameter implant is recommended.
Implant-supported overdentures
These are removable complete dentures which are retained with bar
• Retention and the stability of the denture are greatly improved.
• Support for the dentures is improved anteriorly and the posterior
part of the denture derives support from the underlying mucosa.
• Classic example of implant-supported overdenture is in the
mandible where the denture is supported by two implants placed in
the region of canines. High success rate is reported for implants
placed in the lower anterior region.
• In the maxilla, the failure rate is higher because of the higher
mechanical forces and the poor quality of the bone.
• It is often recommended to place at least four implants which are
rigidly joined together with the bar in the maxilla.
Multiple fixed implant restorations
These are basically implant-retained bridges which can be short span
or can be complete arch restorations in edentulous jaws.
• There are two types of basic designs—one is the Branemark design
and the other is fixed design similar to conventional fixed partial
• Branemark design is called the bone-anchored bridge which
consisted of cast metal bar attached to the acrylic teeth and
gumwork attached to the number of implants. This resembles
• The modern bridge designs similar to the conventional fixed partial
denture are having cast framework extending below the soft tissues
to connect to the implant abutments. The prosthesis can be either
screw retained or cemented. The results are favourable in cases of
minimal bone resorption. This type of design should not be used in
cases of advanced bone loss, especially in the anterior region
because of unfavourable biomechanics and inadequate lip support.
• Cantilevering of the fixed prosthesis with more than one tooth
posteriorly and two teeth anteriorly is not advisable.
• When there is minimal bone resorption
• When the patient has strong gag reflex
• When there is good dentition in the opposing jaw which can
Importance of evaluating edentulous ridge for
The clinical evaluation of the edentulous ridge is important for proper
diagnosis and treatment planning for implant placement. The
edentulous ridge should be carefully palpated and visually assessed
for the height, width and contour of the ridge and the quality of the
soft tissue covering the edentulous ridge.
• The bone height and width should be assessed both clinically and
• Clinical technique, such as ridge mapping, is helpful in assessing the
bone width and the soft tissue thickness.
• The angulation of the ridge is important to assess as proclined or
retroclined ridge will lead to placement of implant in that
angulation and that will drastically affect the aesthetics and result in
• The interarch space is important to evaluate, as this will determine
the amount of space available for the restoration and the implant.
• The soft tissue profile over the edentulous ridge is important to
assess. Keratinized tissues which are firmly bound to the
underlying bone have better prognosis than the soft tissues which
are loosely attached and mobile.
• The length of the edentulous ridge determines the number of
implant which can be placed to get best result. However, this
should always be correlated with the appropriate radiograph.
• Dahl of Germany introduced the mucosal inserts or button implants
• Dahl also conceived the concept of the subperiosteal implants.
• Goldberg and Gershkoff made subperiosteal implant with
• Sollier, Chercheve and Small introduced the transosteal implant in
• L.I. Linkow in 1966 introduced the endosseous blade vent implant.
• First extraoral implant was placed for the auricular prosthesis by
• Implants can be placed minimum 6 months after the radiotherapy.
• Radiation dose of OPG is less than the full mouth periapical
• Lateral skull radiograph is used to study ridge profile of both upper
and lower jaws in the midline.
• In CT scans, the metal markers should be avoided as these produce
• Scan Ora is a new generation sophisticated tomograph which is
used to generate high-quality sectional image.
• Narrow diameter implants less than 3.5 mm should be avoided in
the posterior region or number of implants should be increased.
Narrow diameter implants greatly reduce the strength and the
surface area for osseointegration or load distribution.
• D4 type of bone represents the worst type of bone used for implant
• The factors such as the quality of bone, type and design of implant
to be used, the anatomical anomaly and technique of use determine
the efficacy of the osteotome used in the posterior maxilla.
• The effective radiation dose with CBCT is significantly lower than
• The CT imaging 3G software can produce high-quality images on
the paper, films or in the digital form.
• Surgical template is a useful diagnostic tool to guide the implant in
desired angulation during placement.
• Implant-supported prosthesis has the poorest prognosis of the
patient with parafunctional habits such as bruxer.
• Microstrain can be a favourable stimulus during healing period of
implants resulting in increased bone density.
• The ‘All and 4 Shelf’ concept was first described by Dr Paula Malo
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