article - review Flashcards
situations that could increase implant failure rate
- low insertion torque of implants that are planned to be immediate or early loading
- inexperienced surgeons
- implants insertinginto maxilla
- implants in posterior regions
- heavy smokers
- into bone qualities of type III and IV
- small bone volumes
- shorter length implants
- greater # placed in patient
- lack of stablity
- non-threading / cylindrical implants
- prosthetic rehabilitation with implant supported over dentures
following situations
may be correlated with an increase in the implant
failure rate
- non-submerged technique
- immediate loading
- implant insertion into fresh extraction sockets
- smaller diameter
two major contribting factors to loss / failure irrespective of placement protocol
smokers and short implants
Marginal bone loss has been demonstrated to be
initiated by
poor clinical handling, use of poor
implant designs or by treating complicated patients.
a later stage patient disease, rapidly changing loading situations or reactions to cement particles accidentally embedded in the soft tissues represent other
reasons for start of bone loss
T/F osseointegration is a foreign body reponse
true
- and long term clinical function is dependent on tissue equilibrium
effects of antibiotic pre medication before implant placement
From the results of these studies, it can be concluded that there is some evidence suggesting that
pre-operative antibiotics significantly reduce failures
of dental implants placed in ordinary conditions, but
it is still unknown whether post-operative antibiotics
are beneficial.
some that gave prior - showed statistically significcant survival rates compared to placebo and others didnt show
pre- op antibiotics in smokers?
beneficial because smoker NOT given pre operative antibiotics were almost 3x more likely to have implant failures than those provided preoperative antibiotic coverage
immediate placed implants and post - surgical amoxilcillin use?
if unable to use amoxicillin = 3.4 x more likely to experience implant failure as patients who recieved it
studies exist to support flapless surgerues can have higher failure rates?
yes - shown by sennerby et al
torque to provide osseointegration?
To achieve osseointegration,
it was found that an insertion torque above 32 Ncm
was necessary. It was observed that the insertion torque was associated with the risk potential, which can
be decreased by 20% per 9.8 Ncm added. The authors
suggested that, in cases of early loading, an appropriate initial insertion torque must be applied to decrease
the implant failure rates.
more failure seen in lower torqued implants - especially if immediatley loaded
fresh exrtaction sockets vs healed sites
Some studies showed that there is a greater risk of
implant failures with insertion in fresh extraction sockets compared with placement in healed sites (77–82).
On the other side, few studies showed that there is a
greater risk of implant failures with an early insertion
(within 6–8 weeks after tooth loss) (8
implants placed by inexperienced surgeons (less than 50 implants) failure rate?
3.5% – failed TWICE AS OFTEN as those placed by experienced surgeons
especially in the first 9 implants placed
location conditions
most studies show maxilla having more failure rates (less favorable bone texture + lower density in thin cortical plates)
+ shorter implants in posterior leading to more failures
patient conditions
male vs female - inconclusive
age - not the age but rather the bone quality
smoking
does contribute to failure
bone quality effect - in general
. Bone quality is believed to be one of the
most important aetiological factors for early implant
failures
type I - iv bone
i = homogenous cortical bone
ii= thick cortical bone with marrow cavity
iii = thin cortical bone with dense trabceuluar bone of good strength
iv = very thin cortical bone with low density trabecular bone of poor strength
increased failure rate when placed into ___ bone
type iii and iv
implant length
implants as possible of maximum length should be used. Advantages of increased
implant length include increased initial stability, longterm resistance to bending moment forces, expedited
healing and a decreased risk of movement at the
interface
width of implant
better to have wider
occlusal vs non occlusal loading
Inconclusive
initial stability
Primary implant stability is determined by the bone
density, the implant design and the surgical technique. These studies show a correlation between
implant stability and implant survival and probably
reflect the importance of an undisturbed healing to
achieve adequate osseointegration.
threaded vs cylinrical implants
some showed greater failure with cylindrical implants
number of implants placed per patient
One may hypothesise that placing multiple implants
requires more mucoperiosteal stripping, compromising
blood supply, more operating time and more contamination of the wound, all of which may contribute to
the increased complication rate
implant surface
Statistically significant difference was observed in
comparisons of implant failure rates between
HA-coated and non-HA-coated implants (favouring
HA-coated) (223), turned and TPS (favouring TPS) (253),
turned and anodised (favouring anodised) (37, 188, 254),
turned and ‘rough’ (favouring rough) (20, 184)
cement versus screw retained implants
Cement remnants may indeed cause marginal bone
loss due to a foreign body on another foreign body
reaction, but failure rates will increase first after many
years in situ
see effects of left over cement when?
many years IN SITU afterwards –
splinted implants indicated when?
splinted implants are usually indicated in clinical situations where there is a risk of mechanical overloading to reduce the forces on implants and surrounding tissiues
It has
been suggested that splinting implants helps to distribute functional loads and therefore decrease the
implant failure rates
cylindrical implants without threads
more likely to fail
factors to consider with marginal bone resorption
type of implant
clinical handeling
state of the patient
- main importance for failure
human factor – not everyone is a good surgeon - even if he or she has had proper clinical training and experience
Albrektsson (342)
investigated the clinical outcome of all implants placed
at the Branemark clinic in 1986 and found that one
surgeon was alone
responsible for the majority of failures?
yes - due ot inexperience
and most had marginal bone resorption as well
oral hygeines role
Another threat to implant survival related
to clinical handling may come from inexperienced clinicians (6). It is also important that the whole team
could plan and design a prosthetic suprastructure in a
way that it will be possible for the patient to perform
an adequate routine oral hygiene. For example, nonconnected implants are generally considered to facilitate optimal oral hygiene by the patients because of
superior accessibility.
T/ F There are, in fact, very little if any
evidence of a true connection between periodontitis
and the start of marginal bone loss around oral
implants. F
true - pdl vs ankylosis in implant with low blood ciculation and an almost total lack of interfacial nerves
marginal bone loss and perio implantitis
does not start with the pathogens
has to do with forign body equilibrium
. More severe
marginal bone resorption will lead to peri-implantitis
that may start as an aggravation of the inflammatory
response inevitable to any foreign body such as an oral
implant
need what in future studies
longer
look at 10+ years
conclusion
it may be suggested that
the following situations are correlated to increase the
implant failure rate:
the following situations are correlated to increase the
implant failure rate: a low insertion torque of implants
that are planned to be immediately or early loaded,
inexperienced surgeons inserting the implants, implant
insertion in the maxilla, implant insertion in the posterior region of the jaws, implants in heavy smokers,
implant insertion in bone qualities type III and IV,
implant insertion in places with small bone volumes,
use of shorter length implants, greater number of
implants placed per patient, lack of initial implant stability, use of cylindrical (non-threaded) implants and
prosthetic rehabilitation with implant-supported overdentures
