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  

2. Divisions of available bone:

3. Diviosion a:
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

4. 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

5. Division A implants advantages:
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

6. Division A implants advantages:
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

7. Prosthetic options: 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

8. Removable implant overdenture:
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

9. Group b: barely sufficient bone:
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

10. Three treatment options:
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
Insert narrow division B rootform implant
Modify B by augmentation

11. 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

14. 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

15. 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

16. Success of augmentation is correlates with:
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)
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)
Some regions are better suited(e.g floor of the maxilla ry sinuses)
An alteration for the augmentation ≈ bone speading
( a narrow osteoplasty →bone spreader are tapped in to edentulous site)

17. 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

18. Division C (compromised bone):
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

19. 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

20. 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

22. 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:
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

23. 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

25. 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