Implants in oral and maxillo facial surgery /certified fixed orthodontic courses by Indian dental academy

IMPLANTS IN OMFS

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INDIAN DENTAL ACADEMY
Leader in continuing dental education


Topics –in seminar
 Dental

implants
 Implant retained prosthesis- Ear, Nose & Eye.
 Tmj implants
 Zygoma implants.
 Bone augmentation.
(vertical)


Dental implants- types


Endosseous – types, Root form, Blades, Ramus blade & Ramus
frame.

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ROOT FORMS- if sufficient bone height & width is available this is
choice of implant.
Types –Press fit, Self tapping, Pre tapping (threaded) .
Prosthetic options- used in fixed, fixed detachable, over denture &
single tooth purposes.
Required bone- >8 mm vertical height
>5.25 mm bone width (bucco-lingual)
>6.5 mm bone length (mesio-distal)

Blades

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These are submergible two-stage & single-stage one
piece implants.
Types- Prefabricated, Custom- cast, Alterable (by cutting,
bending, Shaping on chair side)
Prosthetic options- single & multiple tooth
Required bone- >8mm vertical height
>3.0 mm width
>10 mm length.

Ramus blade & Ramus Frame
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One piece blade –used for the post mandible when
insufficient bone exists in the body.
Ramus frame – Three blade, one piece deviece
designed for relatively atrophied mandible.
Prosthetic options – overdentures
Required bone- >6mm verically
>3mm width.


Subperiosteal implants
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Principally used in atropic
mandilble.
Cast metal frame which fits
the jaw bone & has
projections into the oral
cavity on which a prosthesis
may be mounted.
Frame- usually made of
cobalt chromium alloy.
Disadvantage- the implant
host interface is fibrous &
oral epithelial down- growth
eventually occurs around the
implants.

Transosseous implants
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One- piece implants.
A submental incision is required.
Advantage- implant predictable longevity.
Types- single component, multiple component,
staples.
Prosthetic options- usually over dentures, alternative
fixed bridges.
Suitable arch- mandible-ant region, complete or
partial edentulism.
Bone required- >9mm verically
>5mm width.

Implants parts


Body, Apex, Module.


Osseointegration

process where by clinically asymptomatic
rigid fixation of alloplastic materials is achieved
& maintained in bone during functional loading”.
 In 1809 Maggiolo-gold implant in fresh extracted
socket-complicated by post op pain & gingival
inflammation.
 A 2 staged threaded Ti root implant was first
presented in North America by BRANEMARK in
1978.
 “A


Materials and Surfaces
 First

metals used were Gold, Silver, Lead which
had electrolytic reactions when they bought in
contact with body fluids.
 Recently used is Ti-6Al-4V alloy becoming the
metal of choice.
 Exposed to air, 2-10 nm thick oxide layer is
formed & is bioinert.
 HA – plasma sprayed onto a roughened &
prepared Ti implant to enhance bone
connection.

 HA-

ranges from 50 to 70 µ. A pressurized
hydrothermal post plasma-spray increases
the crystalline HA content from 77 to 96%offers improved bone adhesion.
 Despite the success of smooth Ti implants,
use of roughened surface has been
substituted as the current choice of texture.

Time & Reason –Integration & Failure
 Branemark

protocol states 4-6 months for
mandible & 6 months for maxilla to prevent
fibrous encapsulation . This is out dated
because it is based on clinical observation &
not on the biological factors.
 Recently -designed on the microtopograhic
surface & histology.
 Cooper, Felton, I J OMFS implants,2001-96.2%
survival rate of single staged implant in 3
weeks.

Failure
 Endosseous

implants distribute occlusal load
best in Axial direction, but in lateral, many
damaging stress, shear stresses were
generated directly at the crest of bone.
 Over heating during placement- fibrous tissue
against implant surface rather than bone .
 Lack of bone contact leading to lack of
integration & marginal integration.
 Presence of infection.

 Keratinized

gingiva has shown to promote soft
tissue health around teeth.
 Preserving Keratinized gingiva recommended
when placing & exposing implants. Incision
design should result in Keratinized gingiva labial
to the implant.
 In post maxilla, vertical bone loss is due to
excessive cantilever type forces placed on the
implants.
 Improper oral hygiene.

Periimplant Biology


The placement of an implant
between two periodontally healthy
teeth is a unique situation whereby
the bone and soft tissue is
maintained in part by the teeth.

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The suggested depth of placement
of an implant below the free margin
of soft tissue is approximately 3 to 4
mm.


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The distance suggested
from the side of the
implant to the adjacent
tooth should be about 2
mm to avoid horizontal
bone loss affecting the
adjacent tooth.


Crown to Implant ratio

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A crown-to-implant ratio of 1:1 or less is desired.
The minimum length needed approaches 10 to 12 mm
since the clinical crown length frequently approaches this
measurement.
Replacement of teeth in a compromised site gives rise to
single or multiunit restorations that have poor or
unfavorable crown-to-implant ratios. If the restoration
participates in anterior guidance, it should be splinted to
other implants.

Radiographic Classification


Lekholm & Zarb correlated implant success with the
radiographic appearance of the remaining cross- sectional
bone by classifying the amount of remaining cortical to
cacellous bone.
Type 1- Greater than 75% cortical/cancellous bone
Type 2- Thick corical surrounding dense cancellous bone
Type 3- Thin cortical surrounding dense cancellous bone
Type 4- Thin cortical surrounding low density cancellous
bone.

Implant selection
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

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Historically, osseointegrated dental implants were
introduced in their original configuration as a machined
parallel walled screw.
In later years the use of surface-textured press-fit type
implants also became popular because their surgical
installation was simplistic and achieved earlier integration
into softer types of bone.
Current trends -use of tapered macroretentive implant
configurations, based on the fact that tapered screw type
implants have increased surgical stability in soft bone.

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This taper creates a seating effect of the connection
to the internal aspects of the implant; therefore, fewer
lateral stresses are transferred to the abutment
screw, resulting in a less frequent incidence of screw
loosening and fracture.
Consideration of the components makes it easier to
select the appropriate system for both surgical
installation and restoration.


One stage & immediate loading
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Recently, more interest has arisen for placement of
implants into the esthetic zone of the maxilla, with either
immediate loading or the use of a healing abutment that
mimics the natural shape of the tooth.
The hypothesis is that by placing a healing abutment
with natural contours, the soft tissue response will be
enhanced, potentially resulting in a more esthetic final
restoration.
Treatment planning for a one-stage or immediately
temporized anterior maxillary restoration begins with a
list of contraindications.


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A one-stage exposed implant placement at the time
of extraction will require the following:
• No purulent drainage or exudate from the site
• Excellent gingival tissue quality without excessive
granulation tissue
• Lack of periapical, uncontrolled radiolucency
• Adequate bone levels circumferentially without the
need for additional soft or hard tissue grafting


Complications
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Soft tissue complications: seen in areas where the
quantity of keratinized soft tissue is minimal.
Soft tissue may also be compromised in area were
the implant angulation's is not ideal in an esthetic
zone.
Soft tissue depths exceeding 5 to 6 mm may present
with long term maintenance.


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Radiographic Bone Loss :
It is normally expected in implant placement; how
ever this loss should not exceed 1.5mm in the first 12 to
18 months.
Bone loss in excess of this value exposes a
significant portion of the implant surface, making hygiene
procedures difficult.
Screw Loosening :
Abutment and Prosthetic screw loosening can be
a recurrent problem seen often with single tooth
restorations.

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A method of reducing screw loosening is to use a
new abutment or prosthetic screw, torque once to the
recommended torque application, wait 5 min, and then
torque again.
Repeated screw should bring to mind occlusal over
load, heavy contact in lateral excursions or implant
mobility.
Abutment Fracture: is relatively uncommon but
problematic particularly in cemented implants.


Implant retained facial prosthesis
 Auricle,

Orbit, Nasal.
 First introduced by Pare in 1575.
 Metal, Porcelin, Acrylic resin, Chrome cobalt
were the materials used.
 A study by Tolmen & Taylor I J OMF Implants
in1995 showed as -318 mastoid, 98 orbit, 36
nasal bones had a success rate of 99% in
irradiated cases of mastoid, 79% & 81% in orbit
& Nasal bone.

 Implant

placement is guided by design of
prosthesis & availability of sound bone in &
around the defect site.
 Implant placement must be 15mm from the
defect.


Design of craniofacial implants
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Available in wide range of shapes
& surface preparations.
Most widely used Branemark implants.
Implants –shorter than intra oral implants & have
perforated flange.
Flange- increase the implant surface area in bone
contact- mainly theoretical.
Flange- creates a protected environment from infection
which would be difficult to control.
Flangeless 3 mm & 4 mm implants recently introduced.

Auricular implants
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2-3 implants is been placed
in the posterior auricular
region.
This area corresponds the
location of Helix & Antihelix.
Mainly it is limited by the
location of mastoid aircells.


Orbital implants
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3-5 implants were used depending the area of the
defect.
They were placed with in the orbital rim.
Due to complex anatomy implants were placed only in
the superior & lateral part of the rim.
Placement should be parallel or slightly inward in
relation to frontal plane.
Sup orbital rim is reduced or flattened.
Extensive defects implants can be placed in the
Zygoma or Maxilla.

Nasal implants
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Placed in maxillary or frontal bones.
Limiting factors in this frontal sinus & superior margin
of the prosthesis for superior aspect of the defect.
3-4 implants were used.
Implants were placed in outer counters of the
positioner to ensure the best aesthetic results.


Surgical procedure
 Basically

it is 2 staged.
 In stage 1- implants were placed.
 Normally healing takes 3 months & for
irradiated 6 months.
 In stage 2- implants uncovered & exposed
through the skin by connecting abudments.
 Abudments –shorter 1-2mm above the level
of the skin, this decreases stress & less
space.

Retentive system
 Ball

& socket
Magnet & Clips
Bars & clips.
 Delvalle –in 1995 studied the mechanical
evaluation of craniofacial Osseo integration of
retention system. I J OM Implants.
It is concluded as Bars & Clips have high
retention.

Temporomandibular Joint Implants


IndicationsSevere degenerative joint
disease,
Recurrent ankylosis,
Irreparable condyle fracture,
Avascular necrosis,
Neoplasm requiring
extensive resection,
Congenital disorders. (TSC)


Advantages
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Theoretically-advantages for adult is
Lack of donar site morbidity
Occlusal stability (autogenous- resorption)
No need for intermaxillary fixation
Decreased risk of ankylosis from heterotopic bone
formation
Early range of motion.

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Different materials were used & time tested-tantalum,
stainless-steel, vitallium, titanium.

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Boyne -1980 used Ti mesh plate over head –but was
discontinued because of excessive heterotopic bone
formation, leading to ankylosis.
Currently used- Christensen prosthesis.-it is a Vitallium
fossa implant of 0.5mm thick & available in 40 sizes for
Rt & Lt.
Implants secured to the eminence & lateral border of the
zygomatic arch with 2.0mm screws.
2-TYPES –were type 1 not used because it had 6% to
8% of fracture incidence.

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Stock length ranges from 45 – 55mm & secured with
6 to 8 screws.
Care to be taken for inf dental nerve during the
placement of then ant ramal screws.
Pt is capable of only rotational forces –dues to loss of
lateral pterygoid insertion.
Unilateral replacement –deviation to the same side
on opening.


Complication
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Prosthesis displacement &
Fracture
Foreign- body reaction to
polymeric or mettalic debris
Heterotopic bone formation
Damage to inferior alveolar
nerve by screws
Pain
Unilateral deviation


Zygoma Implants
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In 1999 Dr. Per-Ingvar Brånemark and colleagues
introduced the zygoma implant.
Zygoma implant -viable alternative for treatment of
patients with extreme resorption of the edentulous
maxilla or large pneumatized maxillary sinuses.
Initial stability of this elongated fixture is assured by its
contact with four osseous cortices, 1. At the ridge crest
2. The sinus floor 3. The roof of the maxillary sinus
4. The superior border of the zygoma.


Indications
When full maxillary edentulism
is accompanied by advanced
posterior resorption that would
otherwise require grafting.
 In partial or incomplete
maxillectomy patients when
additional implants can be
placed in other sites such as the
piriform sinus, orbital rims,
palatal shelves, or pterygoid
plates to support cross-arch
stabilization.
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Contraindications
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There are only two specific situations that would
complicate the use of the zygoma implant or make it
unnecessary.
First, where adequate maxillary bone exists for implant
placement in numbers and positions to support a
prosthetic appliance, the zygoma implant is not needed.
Second situation is where there is not enough
premaxillary support for at least two stable implants with
good potential longevity.


Complications
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Significant complication is the loss of the implant.
Risk of injury to adjacent structures that is, orbit, orbital
contents, facial nerve, lacrimal apparatus, infraorbital
nerve.
Risk of postoperative sinusitis, although less than with
sinus lift procedures.
Surgical access difficult, deep sedation or general
anesthetic required.
Fixture failure—although rare, more difficult to retreat.

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The schneiderian membrane in the sinus is removed to
allow good visualization and to prevent its interference
with site preparation and implant insertion. If portions of
the membranes are “picked up” by the implant and
carried into the implant preparation in the body of the
zygoma, they could interfere with osseointegration.
The zygoma implant varies in length from 30 to 52.5
mm.
The zygoma implant has an angulated abutment
platform. The 45° angulation allows the platform of the
implant to emerge in the same plane as that of the
conventional implants.

Protective Splinting
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One of the unique features of these implants is the
strength they provide when used with splinting and
cross-arch stabilization.
When used or loaded independently, however, it is felt
that the off-axis load transfer can be detrimental and
possibly counterproductive for maintenance of
osseointegration.
Immediately following stage II surgery, or exposure of all
implants with abutment connections, it is recommended
that some protective measures be used to prevent
independent stress transfer from the denture base to the
implants individually.

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The current protocol calls for splinting all of the newly
exposed implants with a soldered bar within 24 hours
of abutment connection.


Vertical Alveolar Augmentation-Bone
Grafting


Strategies for vertical bone grafting comes in six
categories,
-guided bone graft augmentation
-onlay bone grafting
-interposition alveolar bone graft
-alveolar distraction osteogenesis
-iliac bone graft
-sinus bone graft.


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Augmentations without the placement of implants
generally resorb unless a nonresorbable grafting material
such as hydroxylapatite is used.
Alveolar vertical defects -classified according to the size of
the defect. Deficiencies can range from1 or 2 mm to 20
mm in height. Monocortical grafts or guided bone graft
augmentations are useful for smaller augmentations.
Interpositional grafts work well for moderate-sized defects.
Distraction osteogenesis is reserved for more extensive
alveolar defects.
Sinus bone graft, which functions as an “endosteal”
expansion of alveolar vertical bone mass.

Guided Bone Graft Augmentation
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Techniques allow vertical augmentation of up to 10 mm
both in the posterior and anterior maxilla and mandible.
A barrier membrane is placed and stabilized with tacks or
screws in order to protect an autogenous bone graft
usually harvested from the retromolar area in the
mandible. The membrane is maintained in the site
completely covered by the soft tissues for a period of at
least 6 months.
The implants can be placed either at the time of bone
regeneration or at the membrane removal surgery.

Onlay bone grafting
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Mandibular bone graft are extensively used with great
success rate and include symphysis & ramus buccal
shelf as donar site.
Success with these grafts can be achieved with defects
of up to 6mm.
The posterior maxilla and mandible -most common
areas of deficiency.
Implants are placed in a submerged or nonsubmerged
mode after appropriate healing time with the block grafts.
Quality of bone from the ramus buccal shelf is typically
type 1, and the symphysis normally exhibits type 2.

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Four key principles -First, recipient site preparation must
be done to allow access for trabecular bone blood
vessels and osteogenic cells.
Second, two-point fixation of each block is important to
prevent microrotation of the graft resulting in incomplete
bone incorporation.
Third, primary closure without tension of the wound site
is critical to prevent dehiscence.
Finally, implant placement must follow graft incorporation
and should never be done simultaneously.

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The symphysis can provide a range of dense cortical
cancellous bone ranging from 4 to 11 mm, in contrast
to a typical ramus buccal shelf block graft that is 3 to
4 mm.



These grafts can be used for predictable horizontal
augmentation of 5 to 7 mm and vertical augmentation
of up to and including 6 mm.


Interpositional Bone Graft
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Interpositional bone graft is placed between a mobilized
segmental osteotomy and the basal bone.
Vertical gain is 4 or 5 mm in the maxilla but 5 to 10 mm
in the mandible.
Indication -alveolar defect where there is insufficient
vertical height for placement of implants such as in the
anterior maxilla or in the posterior mandible when a
stable vertical augmentation is required, usually over a
three- or four-tooth segment.


Alveolar Distraction Osteogenesis
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A deficient alveolus can be distracted to improve
vertical dimension for implant placement.
Sufficient width (5 mm) and vertical height (8 to 10 mm)
of a distraction site are needed in order to ensure
sufficient (5 × 5 mm) bone mass of the segment to be
translated.
A biphase distractor plate is placed in order to gain
vertical and horizontal displacement of the bone.


Illiac Corticocancellous Grafting
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When the jaw is too deficient
to do monocortical grafting
or osteotomies, bone graft
augmentation with iliac
corticocancellous graft is
needed.
Major grafting is usually
required when bone mass
needs to be expanded in
order to gain enough bone
for osseointegration.


Sinus Bone Graft
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Three tech are used, 1. Sinus intrusion osteotomy
2. Lateral approach sinus membrane elevation
3. Alveolar augmentation combined with sinus elevation.
The sinus intrusion osteotomy can be done on the day
of extraction if the wound is clear of soft tissue and
infection.
The intrusion was done with a bone graft and implant
placement 6 weeks after the dental extraction.
Bone graft was also placed into defects within the
extraction socket.

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The lateral sinus graft is done through a Caldwell-Luc
approach by elevating the sinus membrane in order to
preserve a “closed wound.”
This approach can be used for both simultaneous and
delayed implant placement.
Barrier membranes are usually not required but benefit
over the grafted site if a large “window” is made.
The use of piezoelectric surgery is helpful in avoiding
perforation of the membrane.


Thank you


Implants in oral and maxillo facial surgery /certified fixed orthodontic courses by Indian dental academy

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