Transcript Slide 1

Divisions of available bone:
PRESENTED BY:DR.GLAREH EBLAGHIAN
SUPERVISED BY: DR. MANSOUR
RISMANCHIAN
AND DR.SAIED NOSOUHIAN
DENTAL OF IMPLANTOLOGY
DENTAL IMPLANTS RESEARCH CENTER
ISFAHAN UNIVERSITY OF MEDIACAL SCIENCE
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Divisions of available bone:
DIVIOSION A:
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Aboundant bone that forms soon after extraction or a few years
after extraction
For group A implant of 12mm or more can be successful without
compromise (very long implant is not necessary because of stress
to the implant-bone interface
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Implant diametter is at least 4mm at the crest module
In the bone width greater than 7mm(A+): 5mm implant may be
inserted
Osteoplasty may be performed
Division A should not be treated with smaller diametter implant
A patient with division A bone should be notified that this is the
ideal time to restore their edentulous condision by implant
Division A:decrease in treatment cost, increase in benefits
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DIVISION A IMPLANTS ADVANTAGES:
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The larger the diameter, the greater surface area and the less stress
distributed through the crestal bone region
The larger implant is closer to the lateral cortical plate that increase strengh
The larger diameter implant is less likely to fracture because the strength of
the material is increased four times by diameter
The smaller diameter implant are often one piece and require an immediate
restoration. So likely loading and micro movement may be occure with the
crestal bone loss
The larger diameter teeth can be more esthetically restored with the wider
diameter implant
The large implant diameter, the less stress applied to the abutment screw,
and screw loosening and fracture are less
The larger diameter make greater cement retention for final restoration
Oral hygiene are more compromised around smaller diameter implant with
overcontour restoration
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DIVISION A IMPLANTS ADVANTAGES:
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The crestal module of many two piece small diameter implants
are smooth metal thus creating shear loads to the crestal bone
Division A root form implants are designed for variable bone
density and can provide the greatest range of prosthetic
options
Implant cost to patient
is related to implant
number not diameter
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PROSTHETIC OPTIONS:
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FP1 prosthesis requieres division A
FP2 prosthesis requiers division A → is most common posterior
restoration in partially edentulous patients
FP3 is the option selected in anterior division A bone when
smiling lip line is high for maxilla or low for mandible
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REMOVABLE IMPLANT OVERDENTURE:
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The final position of the tooth and suprastructure bar must be
evaluated before surgery
Final RP4 or RP5 may require osteoplasty
division A may have contraindicated for high profile O-ring
attachment or suprastructures placed several mm above
tissue
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GROUP B: BARELY SUFFICIENT BONE:
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As the bone resorbes the wide of available bone decreases at the expense
of the facial cortical plate
25% decrease in bone width at the first yeare and 40% decrease within 1 to
3 yeares after tooth extraction
After these , bone volume may remain for more than 15 yeares in anterior
mandible
The posterior maxilla have less available bone height because of sinus
expansion
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THREE TREATMENT OPTIONS:
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Modify the existing division b to another by osteoplasty to
permit placement of root form 4mm implant in width
if more than 12mm bone height is available →convert to
division A
if less than 12mm bone height is available → convert to division
C-h
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Insert narrow division B rootform implant
Modify B by augmentation
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To select the proper approach the final prosthesis must first be
consider
When division B changed to A by osteoplasty the final prosthesis
has to compensate d for increased CHS
If the ridge is deficientin width for implant , it is not unusual to
remove 3mm of crestal bone but it tends to extended tooth(FP2 or
FP3)
Osteoplasty is less likely treatment of choice for FP1 prosthesis
with a B-W ridge because greater bone reduction is required
The most common approach is to modify division B to A by
osteoplasty when final restoration is implant overdenture
If the ridge height is reduced so that CHS is greater than 15 mm ,
the bone division changed to C-h( when cantilever or lateral forces
are present , is not predictable for endosteal implant placement)
RP4 & RP5 most often requires osteoplasty to make adequate
CHS
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•The second main treatment option for narrow bone in division B
is small diameter root form implant (3 to 3.5mm)
•The implant body must bisect the bone and implant angulation is
less flexible
•This option is used for single tooth replacement of maxillary
lateral incisor and mandibular incisors when mesiodistal width is
restricted
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Thirdaltration: grafting the edentulous ridge with outogenous or combination of
allograft and alloplast to change division B to A
A healing period of at least 4 to 6 month is needed
FP1 restoration most often mandates option
Stress factors may also dictate the surgical approach : in presence of
unfavorable stress, the number and width of abutment should be increased
without increasing the CHS
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Success of augmentation is correlates with:
I. Number of osseous wall in contact with the graft
material(5 wall bony defect as a tooth socket is
more predictable than one- wall defects as an
onlay graft)
II. Bone augmentation is more predictable when is
minimal and for width( 1 to 2mm increase in width
may be obtained with an alloplast and GBR , more
than 2mm needs autologous block graft)
III. Some regions are better suited(e.g floor of the
maxilla ry sinuses)
IV.An alteration for the augmentation ≈ bone speading
( a narrow osteoplasty →bone spreader are tapped
in to edentulous site)
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If division B-W ridge contour should be altered an onlay particulate
or block graft of outogenous bone is indicated( from symphisis or
ramus)
The implant placement should be delayed for 4-6 month
The patient delayed treatment with division B bone should be
notified if the future bone resorption and so augmentation in height
is much less predictable
the final prosthesis is dependent on the surgical options:
Fixed prosthesis for grafted ridge
 removable prosthesis for osteoplasty
The treatment option may be influenced by the region:
For anterior maxilla→augmentation
For anterior mandible →osteoplasty
For premolar region→division B rootform implants
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DIVISION C (COMPROMISED BONE):
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Division C is deficient in one or more dimention ( width, length or
angulation)
Resorbtion pattern occures first in width and then in height
B→ continuse to resorbe in width but height is still present→C-W →available
bone is the reduced in height →C-H
posterior region of ridges result with division C-H more rapidly than anterior
region because of maxillary sinus and mandibular canal
when anterior mandible is C-H the floor of the mouth is level with the crest
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The fast of resorbtion: C –W to C-H ≈ A to B ≥ B to C-w
 without implant or bone graft C-h will evolve in to D
 the division C does not offer as many elements for predictable endosteal implant
survival:
 anatomical landmarks to determine implant angulation or position in relation to
incisal edge are not present so more skill in surgary is needed
Division C ridge implant supported prosthesis is more complex and have more
complication in healing, design, and long term maintenance
Altered treatment plans that decrease stress can provide predictable long term
treatment
Subdivision C-a : adequate bone in height and width but angulated is greater than 30
degree
C-a is more in anterior mandible , maxilla with sever facial undercut and second
molar with a sever lingual undercut
Root form implant in this category may be positioned within the floor of the mouth
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THERE ARE 7 IMPLANT TREATMENT OPTION:
C-W may be treated by osteoplasty and convert to C –h
the most common available bone alter osteoplasty of C-w is C-h
not A because CHS is more than 15mm
The C-w osteoplasty may convert the ridge to division D especially
in the posterior mandible or maxilla
 Alter division C by grafting
for fix prosthesis→autogenous graft prior to to implant palcement
to acquire proper lip support and ideal CHS
the C-h posterior maxilla is a common and unique: because of the
initial ridge width dimention a decrease of 60% in dimension still
is sdequate for 4mm implant
the maxillary sinus expands after tooth loss
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Sinus graft : elevated the maxillary sinus floor membran and graft the previus
sinus floor
is most predictable region to augment in exess to 10mm in vertical
Various implant approach in division C-h:
1. Shorter implant are the most common(4mm or more in in width and 10mm
or less in height)
several studies indicated implant survival is decrease for implantby 10 mm or
less
2. When greater crown height is occure additional impalnt should be placed to
increase overal impalnt bone surface
in removable prosthesis should iften reduse cantilever lenght
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Alternative designe in posterior mandible division C-h are
subperioseal and disk like design implant especially in
mandibular arch
the limitation of antomy for root form implants may be :
Bone angulation: premucosal posts may be designed with
greater latitute than endosteal implants
Square arches for anterior root form implantsmay have distally
cantilever because of poor anteroposterior distance
a fix or RP_4 overdenture prosthesis is contraindicated with
anterior root form in square arch form
a subperiosteal may provide anteroposterior bone support and
RP-4 prosthesis
Surgical risk of nerve repositioning and parasthesia
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Disk designe implant in posterior mandible or premaxilla : engages lateral
aspect of cortical bone and may be used in height of 3mm
eliminate of cantilever in full arch restoration
prosthetic option for divisionC : removable prosthesis in maxillary arch
support the uper lip without hygine compromised
in the mandible : soft tissue support for restoration
 fix prosthesis in division c with greater than 15mm CHS is hybrid divice
In general: additional impalnts or tooth, cross arch stabilization, soft tissue
support, opposing removable prosthesis often need to be considered
 an alternative method for maxilla: changing the division with
nonresorbable hydroxy apaite
augmentation is only a delayed tactic for bone resorbtion and it doesent
stimulate or maintained bone mass
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