What are the main
complications of implant treatment?
The implant does not osseointegrate.
The possibility of this occurring is dependent upon the area
of the mouth where the implant is placed and the quantity and
quality of the bone available. This reflects the ability of
the dentist to achieve an implant, which is placed firmly with
a large surface are of bone in contact with it.
To generalise the risk of non-integration is as follows:
Lower anterior and pre molar
Lower and upper molars
Upper anterior and premolar
Upper last molar
1 in 30
1 in 20
1 in 20
1 in 15
Should the implant have failed to integrate it can be removed
at the abutment connection stage and subject to healing and
bone availability another implant can be placed.
During my implant career I have only had two implants fail in
the same site on two occasions.
The long-term success rate of osseotite 3i implants, which have
integrated, is 99% over 15 years. It would be incorrect for
any practitioner to provide patients with a lifetime guarantee
however in my experience if following a 5 year post placement
assessment the bone level remains constant around the implant,
it would indicate that the implants will have a significant
life expectancy.
Bleeding and infection These complications will always be a risk in any surgical
procedure however in my experience I have never had a patient
who has experienced acute post operative bleeding and only one
case of infection which was attributed to a non healed previous
tooth infection.
Nerve involvement Trauma to the ID nerve. Should the nerve be damaged and
the feeling not returned within 6 months the numbness to one
side of the lower lip will be permanent. I control all implant
placements over the ID nerve by using CT scans and steriolithography
to plan advanced placement. To place this into the correct perspective
no patient whom I have carried out such treatment has experienced
any long-term nerve complications.
Adjacent tooth involvement During normal implant placement there is a very small risk
to adjacent teeth. In certain circumstances where the tip of
the adjacent root is curved towards the implant site there is
a risk that the blood supply to the adjacent tooth can be lost.
In these cases a root canal therapy may be required to the tooth
involved.
What is a bone augmentation? There are two distinct types of bone augmentations.
Local augmentation This type of graft is used where some of the implant is
not covered with bone following implant placement. The augmentation
uses bone collected during the implant placement and local bone
site near the implant site to cover the threads and regenerate
bone to cover the exposed threads. Sometimes a substitute bone
and membrane is also used see below.
Onlay augmentation This type of bone augmentation is used when there is not
enough bone to place an implant. The bone is taken from inside
the mouth normally from the chin of back of the lower jaw or
when a larger amount is required from the hip and placed onto
the proposed implant site. The area is left for 4 months to
allow healing before implants are placed.
What is a membrane and why is it used?
A membrane is made from a type of plastic or from specially
treated pigskin. The body absorbs the membrane after a few weeks
and dose not require removal. The function of a membrane is
to act as a barrier to epithelial cells during healing. This
helps the graft to change into bone rather than fibrous tissue.
What is bio-oss or substitute bone and
why is it used?
Substitute bone is derived from a number of sources. The main
substitute, which I use, is called Bio-oss, which is from a
cow, which have undergone very strict clinician and breading
screening. I recommend its use to avoid the need for augmenting
bone from another site. Bio-oss also has the advantage of being
more slowly resorbed by the body than the patients own bone
and helps to preclude epithelial cells from preventing bone
formation during augmentation.
My patient does not want any
animal derived products used in their mouth.
Patients who for a number of reasons do not wish to have animal
products used should inform us during the consultation stage
where we can discuss the alternatives.
What is a sinus lift? A sinus lift is a procedure, which involves the creation
of bone within the maxillary sinuses. Following extraction of
the molar teeth the height of bone between the mouth and sinus
can become too low to predictably place implants this is due
to bone resorbtion and enlargement of the maxillary sinuses.
Bone can be augmented into the sinus to regain the height required,
in a similar manner to an onlay augmentation.
What is the difference between
an over denture and a fixed bridge? An over denture is a denture which is secured into
the mouth with implants. Unlike a conventional denture it moves
very little compared to a conventional denture during eating.
The overdentures can be removed to allow cleaning. A fixed bridge
is directly secured to the mouth using dental cement or screws.
It does not move during function and is not removed during cleaning.
How many implants are required
to replace missing teeth? It is only possible to provide a guide to this question,
as it will depend upon the number of teeth missing, the quality
and quantity of bone available, the location and the load, which
may be placed upon them.
Please see the chart below for a guide.
Position
Number of teeth missing
Number of implants
Front teeth
1
1
2
1-2
3
2
4
2
5
3
Side and back teeth
1
1
2
2
3
2-3
4
3-4
Lower overdentures
All
2
Upper overdentures
All
4-8 (6)
Lower fixed bridge
All
4-8 (5)
Upper fixed bridge
All
6-10 (8)
Numbers in brackets (x) represent the most common number of
implants used.
