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2. INTRODUCTION
The use of dental implants has enabled the
fabrication
of
restorations
and
highly
functional
improved
the
and
esthetic
predictability
of
treatment. However, at any point during rehabilitation
and maintenance complications and failure can occur.
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4. IMPROPER PATIENT SELECTION
The critical selection of patients and the critical
application of dental implants are the two most
important pre requisites for the treatment success we
all desire (Lanney 1986)
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5. BONE DENSITY
A key determinant for clinical success
Highest clinical failure rates have been reported
in posterior maxilla
Linkow in 1970 classified bone density into three
categories.
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6. Class I
:
Consist of evenly spaced trabeculae
with small cancellated spaces.
Class II
:
Consist of slightly larger
cancellated spaces with less
uniformity of the osseous pattern
Class III
:
Large marrow filled spaces exist
between bone trabeculae
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7. In 1988 Misch classified bone density into
D1
Dense cortical bone
D2
Thick dense to porous cortical bone on crest
and coarse trabecular bone within
D3
Thin porous cortical bone on crest and fine
trabecular bone within
D4
Fine trabecular bone
D5
Immature, nonmineralized bone
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8.
As the bone density decreases the strength of
the bone also decrease.
Stress can be reduced by :
A.
B.
Narrowing the occlusal table design.
C.
Wider implants
D.
decreasing the cantilever length
HA Coatings
0.5mm increase in width – 10% - 15% increase in
surface area.
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9. AVAILABLE BONE
As a general guideline 1.5mm of surgical error is
maintained between the implant and any adjacent
landmark.
The height of the available bone is measured
from the crest of the edentulous
ridge to the
opposing landmark such as the maxillary sinus or
mandibular canal in the posterior region.
The anterior region are limited by the maxillary
nares or the inferior border of the mandible.
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10.
After estimating the available bone height by
panoramic
accordingly.
radiograph,
the
implant
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is
selected
11. Another criteria is bone width, which is
measured between the facial and lingual plates at the
crest of the implant site.
Root form implant of 4.0mm crestal diameter
usually require more than 5.0mm of bone width to
ensure sufficient bone thickness and blood supply
around the implant for long term success.
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12.
Placing implant of 10mm length in division D bone
without bone augmentation will lead to perforation of
anatomical landmarks or impingement of nerves leading
to parasthesia.
Hence selection of implant after estimating the
available
bone
is
one
of
the
complication and implant failure.
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way
of
reducing
13. DIABETES MELLITUS
More prone to infection
Slow healing tissue necrosis
A ten day regime of broad spectrum antibiotics
should be begun on the day of surgery to reduce the
risk of infection.
High success rate is reported when dental
implants are placed in diabetic patients whose disease
is under control.
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14.
Kapur et al in 1998 compared 37 diabetic
patients
who
received
conventional
removable
mandibular overdentures versus 52 who were fitted
with implant supported ones and concluded that
implants can be successfully used in diabetic patients
under control.
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15. SMOKING
Nicotine 50% reduction in oxygen to the bone
Have greater risk of developing peri implantitis.
Increased resorption of peri implant bone
If untreated
Implant Failure
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16.
Failure rate of 11.28% for smokers compared to
4.76% for non smokers have been reported. (Senerby
and Roos).
Smoking cessation will results in improved
periodontal health and improve a patient chance of
successful implant osseointegration.
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17. BRUXISM
The most common cause of early loss of rigid
fixation is parafunctional habits.
Such complications occur with greater frequency
in the maxilla because of decreased bone density.
A 37 – year old patient with a long history of
bruxism recorded a maximum bite force of more than
990 Psi (4-7 times normal).
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18.
The best and easiest way to diagnose bruxism is
to evaluate the wearing of teeth.
It is not a contraindication for implant dentistry,
but once the source of additional force on the implant
system is identified, the treatment plan is altered to
lower the negative impact on the implant, bone and
final restoration.
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19. PATIENT UNMOTIVATED TO CONTROL PLAQUE
Not good candidates for dental implant
Accumulation of plaque on the implant surface (if
not treated) will lead to peri-implantitis.
Management includes patient motivation to oral
hygiene procedure and regular follow up.
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20. OSTEOPOROSIS
It is age – related disorder characterized by
decreased bone mass and susceptibility to fracture.
Placement of implant in patient with osteoporosis
will significantly effect the success rate.
Implant design should be greater in width and
coated with HA to increase bone contact.
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22. HEMORRHAGE
Bleeding may result from
Soft dissection
Intraosseous surgery
Managed by applying
Managed by forcing
pressure for 5-10mins
sterile bone wax into
bleeding site.
Placement of implant itself in the final prepared
osteotomy ceases bleeding .
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24.
Perforation on the lingual aspect of the alveolar
process in the distal segment of the jaw causes lingual
artery injury.
This may lead to life
threatening
obstruction.
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airway
25. INFERIOR ALVEOLAR NERVE INJURY
When an instrument or the implant contacts the
nerve, the patient experiences a pain sensation even
under anesthesia.
Implant installation should postponed and a
shorter implant should be placed at a later date.
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26. LINGUAL NERVE INJURY
Damage to the lingual nerve leads to loss of
sensitivity in the anterior two thirds of the tongue.
This can be prevented by avoiding any type of
release incision in the lingual direction.
Incisions must always be crestal, with vestibular
release incisions.
Flaps on the lingual side must be elevated
carefully, in tight contact with the bone.
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27. OPENING THE NASAL OR MAXILLARY SINUSES
After completion of implant bed preparation the
bed should be carefully probed, to identify any possible
perforation.
If an oro-antral or an oro-nasal tract is
detected radiographs must be taken immediately.
If perforation is minor, a shorter implant is
placed and the patient is completely informed.
Antibiotic coverage prescribed.
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29. BROKEN BUR
Occurs when the bur gets bind to the bone and
an effort is made to remove it by wriggling the
handpiece shank.
Prevention grasp the handpiece beneath its
head at the point of bur emission with the thumb and
fore finger and press the fingers together.
The bur is pinched between its head and the
bone, and forced it vertically upward and out of the
bone in a non-torque influenced movement.
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30.
If broken bur occur radiograph taken
Usually broken bur is deep in the osteotomy
Patient informed
Aggressive attempts to remove the bur should
be avoided
If bur is not in a critical location it is best to
leave it untouched.
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31. OVERSIZED OSTEOTOMY
Cause
Lack of experience
Prevention
Bone tapping and implant seating ultra low
speed handpiece
Using a mark on the rotary instrument to dictate
the exact moment to reverse the motor direction.
Safer approach – stop the motor at a point four
to five rotations from final seating and complete the
procedure with thewww.indiandentalacademy.com wrench.
hand held ratchet
32. Treatment
Large diameter implant
If osteotomy becomes oversized, for an implant
system where there is no larger diameter implants
then remove the implant and place some particulate
hydroxyapatite graft material and then place the
implant.
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33. FETAL AIR EMBOLISM
Cause
Injection of a mixture of air and water through
the hollow dental drill directly into the mandible, into
the facial and pterygoid plexus veins, and hence the
superior vena cava and right atrium.
Death occur from improper use of a cooling
spray of compressed air and water for apical internal
irrigation.
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34. Prevention
High speed turbine drill with lateral escape
route
Suction placed closed to the cutter creates a
negative local pressure that eliminates any risk of air
embolism.
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35. ACCIDENTAL SWALLOWING
Many implant components are small, when coated
with
saliva
escape
clinicians
grip
and
fall
into
oropharynx.
If this occurs, patient should be placed
immediately with head down position to recover the
lost component.
If this proves impossible, transported with head
low position to the hospital for endoscopic examination.
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36. Prevention
Use
of
manual
screw
drivers
and
similar
instruments equipped with safety wire of dental floss
(min.10cm long)
Correction
Specially trained medical team needed for non-
invasive endoscopic removal of large components.
Very small components – High fiber diet for
patient.
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37. FRACTURED CORTICAL PLATES
Cause – misdirection of a drill
Presence of an unexpected anatomic irregularity
If periosteum is attached to cortical plate- good
prognosis.
If the fragment becomes detached, it can be
wedged back into position, but the prognosis is
guarded.
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38. MANDIBLE FRACTURE
Manson et al 1990 – said that fracture of
mandible in connection with the placement of dental
implants is relatively rare.
Fracture can occur
During bone
site preparation
Excessive stress
during mouth opening
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39. Factors responsible for fracture
Atrophic thin mandible
Multiple implant placements
Increased vulnerable
Mechanical strength is
To thermal injury
Decreased
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40. Prevention
Limited stress to jaw during healing period
Avoid over tightening of screws
Do not use wide diameter implants with large
threads
Management
Immediate implant retrieval from fractured
bone
Rigid connection of osseointegrated implants
with rigid external fixation in order to obtain
immediate stability.
Soft diet for 45 days
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42. HEMATOMA
Prevented by
Proper intraoperative hemorrhage control
Careful post operative compression of the
mucosa flaps covering the implants
Immediate application of cold
packs
In case of extensive hematoma – antibiotics are
prescribed to prevent secondary infection.
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43. INCISION LINE OPENING
It
is
the
most
common
post
operative
complication
If the design of the removable interim
prosthesis is involved, it is corrected
The patient is instructed to rinse 2-3 times daily
with chlorhexidine and gently debride the incision line
with a soft brush
Within few days to weeks the soft tissue will
granulate into the opening.
Resuturing is contraindicated.
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45. CHRONIC PAIN
Implant placed close to mandibular canal may
cause irritation of the inferior alveolar nerve
Such patients may experience chronic pain
Even in the advanced stages of peri-implantitis,
the inferior alveolar nerve may become effected.
Antibiotics are prescribed followed by removal
of the implant as soon as the acute symptoms subside.
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46. RADIOLUCENCIES
If, at 4 or 8 weeks postoperative examination,
the
radiographs
shows
periimplant
osseointegration will not occur.
The patient is informed and
the implant is removed.
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lucency,
48. IMPLANT EXPOSURE
Cause
-
Suturing the flaps under tension
-
Pressure from soft tissue borne
prosthesis
The wound is left open
The denture is modified so as no to exert force
on the area of implant exposure.
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49.
Patient is instructed to use dry cotton – tipped
applicator to keep it free of material alba.
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50. IMPLANT MOBILITY
Due to
Bone necrosis
Implant movement
Infection
Patient should be informed about the situation
and the implant should be removed to prevent further
damage.
Infection
(+)
(-)
Implant installation is
Larger diameter implant
postponed
placed
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52. LACK OF OSSEOINTEGRATION
Osseointegration
is
a
contact
established
between normal and remodeled bone and an implant
surface without the interposition of non bone or
connective tissue.
Three are two ways of implant retention (de
Putter et al 1985).
Mechanical
Bioactive
Metallic substrate system
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HA
53. Causes (Meffert)
Premature loading, earlier than initial healing
phase
Apical migration of junctional epithelium
Placing the implant with too much pressure
Over heating the bone during site preparation
Implant not fitting the site exactly.
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54. Carlsson et al created bone to implant gap of
0mm, 0.35mm, and 0.85mm respectively in rabbit
tabiae. Those with a gap of 0mm had direct bone to
implant contact.
A 0.35mm gap resulted in few areas
of direct bone to implant contact and 0.85mm gap
resulted in no direct bone to implant contact, indicating
the need for close approximation between bone and
implant for rigid fixation.
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56. CRITERIA FOR IMPLANT SUCCESS
(Smith & Zarb)
Individual unattached implant should be immobile
No evidence of peri-implant radiolucency
Mean vertical bone loss less than 0.2mm annually
after the first year of function or service.
No persistent pain, discomfort, or infection
attributable to the implant
There is an 85% success rate at the end of a 5
year postrestorative period, with an 80% success rate
at the end of 10 years postrestorative or function.
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57. SCREW LOOSENING AND FRACTURE
More common in maxilla 50% than mandible 20%
Causes
Inadequate torque application
Inaccurate framework abutment interface
Arch form
Cantilever extension
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58. INADEQUATE TORQUE APPLICATION
Recommended torque for prosthetic gold screws
is 10 Ncm and for abutment screw is 20 Ncm
A manual torque converter is available to adjust
torque between 10 Ncm and 20 Ncm.
It is recommended that all screws be tightened
with a torque driver.
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59.
Patients are advised at the prosthetic delivery
appointment and during hygiene recall appointments to
monitor for prosthesis loosening.
If movement is present, saliva can be seen
percolating at the interface
The prosthesis is removed and all components
are examined.
If any of the screws are loose, they are
replaced.
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60. ARCH FORM
When an arch form is maintained a tripod effect
lessens bonding moments transmitted to the screw
joint.
The destructive forces cause loosening of
prosthetic and abutment screws as well as fracture of
the screws.
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62. CANTILEVER EXTENSION
The cantilevered distance beyond the distal
implant determines the lever arm length and the
amount of force that is transmitted to the implants,
framework and component.
For mandible 15mm or less
For maxilla 10mm or less
Factors
Arch form
Bone quality
Parafunctional habits
Over extension of the cantilever may lead to
Screw loosening
or Fracture
Prosthesis
loosening
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Implant loss
63. INACCURATE FRAMEWORK ABUTMENT
INTERFACE
An ideal framework abutment connection is one
that has circumferential contact and is without an
opening at the interface.
A non passive fit will create stresses in the
screws and on the implant
Screw loosening and lack of osseointegration
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64. When evaluating the fit, screws should
tightened one at a time while observing the lift of
frame and the open interfaces.
Torquing all screw before evaluating
interface may bend the framework giving
appearance of accuracy.
be
the
the
the
If these frames are allowed to seat will cause
constant stress on the implant and the component.
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65. IMPLANT FRACTURE
Fractures occurs due to
Fatigue
Trauma
The most frequent area of fracture is just
below the abutment level.
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66.
Treatment includes removal of the fragments
Usually apical portion of the implants is
osseointegrated and should be left behind, if not to be
replaced, to prevent further osseous loss (Maeglin
1988)
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67. ESTHETIC COMPLICATION
It is a major problem in maxillary anteriors due
to
-
Labial inclination of implants
Gingival recession
Implant inclination can be corrected using angled
abutments upto 30°
Gingival recession requires mucogingival surgery
for correction.
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68.
Gingival margin, normally follows crestal bony
margins.
Gingival recession often occurs if the facial
plates of the bone is lost or if it is extremely thin
following implant insertion.
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70.
Zarb et al 1990 – reported an increased
incidence of framework breakage if extensions in the
mandible exceed 20mm.
The
fractured
solder
joint
is
reindexed
intraorally and then soldered.
The heat of soldering will destroy any acrylic
veneering material, which is replaced after the
framework fit has been verified after soldering.
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71. UNFAVOURABLE IMPLANT LOCATION AND AXIS
ORIENTATION
Esthetics, phonetics, hygiene and prosthetic
design may be compromised by poor implant position.
In extreme situations, implants may be so poorly
positioned that it is impossible to include them in the
treatment plan.
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72.
Block et al 1990 – demonstrated that implants
with an axis orientation angle of greater than 30° were
more likely to be associated with peri-implant bony
defects.
17° or 30° of angulation can be corrected by
placing angulated abutments.
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74. AILING IMPLANTS
It is least seriously affected of the three
pathologic states.
Exhibits soft
tissue
problems
mucositis.
Have a favourable prognosis.
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(Peri-implant
75. FAILING IMPLANTS
Shows evidence of
-
Bleeding upon probing
-
Purulence
Pocketing
Progressive bone loss
Have a poorer prognosis when compared with
Ailing Implants
If properly treated, a failing implant may be
saved.
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76. FAILED IMPLANTS
Horizontal mobility beyond 0.5mm
Rapid progressive bone loss
Pain during percussion or function
Continued uncontrolled exudate
Generalized radiolucency around an implant
More than one half of the surrounding bone lost
around an implant
Implant inserted in poor position making them
useless for prosthetic support. (Sleepers)
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77. MAINTENANCE GUIDELINES
The long term success of the dental implant lies
to a great
extent, in the ability of the patient to
control daily plaque.
A twice daily for 30 sec. Chlorhexidine rinse is
recommended for at least 1 week after stage 2
surgery.
A soft tooth brush or
flat end-tuft brush is used in
addition to rinsing. www.indiandentalacademy.com
78.
Plastic sealers are used to remove calculus
Metal instruments, including ultrasonic scalers,
are not recommended.
Rough surface
Plaque accumulation
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79.
After removal of hard deposits the prosthesis
and abutments are selectively polished with a
Rubber cup
Flossing cord
Aluminum oxide polishing paste is recommended
to avoid scratching of the titanium abutments and
prosthetic suprastructure.
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80. MAINTENANCE INTERVALS
Appropriate recall intervals are determined on
an individual basis, taking into consideration the
patient’s history and present evaluation.
At prosthesis delivery
Oral hygiene instruction given
One month after prosthesis delivery
Review of home care techniques
Calculus removal and coronal polish
Three months later
Examination of tissues
Calculus removal and coronal polish
Establishment of a recall interval between
3 & 6 months
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81. CONCLUSION
There are three most basic principles for
implant therapy.
Do not harm
Evaluate risks and benefits
Avoid over treatment
One should not have heroic effect
Implant therapy should only be provided when all
of the pre requisites for success are present and when
the patient can be better served by means of implant
prosthesis treatment than by conventional prosthetic
replacement.
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82. BIBLIOGRAPHY
The Branemark implant system – John Beumer
(III)
Implant prosthodontics - Stevens
Implant dentistry – Carl E.Misch
Atlas of oral implantology – A Norman Cranin
Implantology - Hubertus Spiekermann
Implants and restorative dentistry – Carl E.
Misch
Clinical Periodontology – Carranza
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83. Thank you
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