bone density 4

7/30/2019 Bone Density 4

1/24

Bone density and typesDr. Mahvesh hasan

FCPS

II ResidentDept. Of Operative Dentistry

DIKIOHS


2/24

Osseointegration

Osseointegration refers to a direct structural and functionalconnection between ordered, living bone and the surface of

load-carrying implant.


3/24

A direct bone-to-metal interface without interposition of no

tissue

Branemark showed that titanium implants could becomepermanently incorporated within bone that is, the living bon

become so fused with the titanium oxide layer of the implantwo could not be separated without fracture.


4/24

Currently, an implant is considered as osseointegrated whenno progressive relative movement between the implant andwith which it has direct contact.


5/24

Classification of bone tissue

WOVEN BONEIt is relatively weak , disorganized and poorly mineralized. It pcrucial role in wound healing by

Rapidly filling osseous defects

Providing initial continuity for fractures and endosteas impla

Strengthening bone weakened by surgery or trauma

The first bone formed in response to wound healing is the wbone type


6/24

Woven bone is not found in the adult skeleton under normastate conditions

Remodelled to lamellar bone or rapidly resorbed premature

LAMELLAR BONE

Strong, highly organized well-mineralized tissue makes up m99 % of the adult human skeleton


7/24

Bone Remodelling

Remodelling is a process of resorption and formation at thethat replaces previously existing bone and primarily affects tinternal turnover of bone including the region where teeth athe bone next to an endosteal implant

The greater the magnitude of stress applied to the bone thethe strain observed in the bone. Bone modelling and remodprimarily controlled in part or whole by the mechanical envof strain


8/24

Stress is determined by the magnitude of force divided by thfunctional area over which it is applied

Strain is defined as the change in length of a material divideoriginal length


9/24

Biomechanical functions of maxilla amandible

The maxilla and mandible have different biomechanical func The mandible as an independent structure is designed as a f

absorption unit. Therefore when teeth are present the outebone is denser and thicker and and the trabecular bone is mand dense


10/24



11/24


The maxilla is a force distribution unit. Any strain to the maxilla is transferred by the zygomatic arch

palate away from the brain and orbit

As a consequence the maxilla has a thin cortical plate and fitrabecular supporting the teeth

Bone density in the jaws decreases after tooth loss


12/24


13/24


14/24

The most dense bone is usually observed in the ante

mandible, followed by anterior maxilla and posterior

mandible and the least dense bone is typically found

posterior maxilla.


15/24

Cortical and trabecular bone

Dense or porous cortical bone is found on the outer surfaceand includes the crest of an edentulous ridge

Coarse and fine trabecular bone types are found within the shell of cortical bone and occasionally on the crestal surface

edentulous residual ridge


16/24


17/24

Misch Bone Density Classificatio

D 1 bone is primarily dense cortical bone

D 2 bone has dense-to-porous cortical bone on the crest anthe bone has coarse trabecular bone

D 3 bone types have a thinner porous cortical crest and finetrabecular bone in the region next to the implant

D 4 bone has almost no crestal bone. The fine trabecular bocomposes almost all of the total volume of bone next to the


18/24

Misch Bone Density Classification


19/24

Misch Bone Density Classification


20/24

The bone density may be determined b

Tactile sense during surgery

General location

Radiographic evaluation


21/24

Bone Density Determined ByGeneral Location

D 1 bone is almost never observed in the maxilla and is rareobserved in most mandibles. In the anterior mandible D 1 bobserved approximately 6 % of the time.

D 2 bone is the most common bone density observed in the

The anterior mandible consisits of D 2 bone approximately tof the time


22/24

Bone Density Determined ByGeneral Location

The bone density D 3 is very common in the maxilla . More tthe patients have D 3 bone in the upper arch

The softest bone D 4 is most often found in the posterior m( approximately 40 %) specially in molar regions

A more accurate determination of bone density is made witcomputerized tomograms before surgery or tactilely during surgery


23/24

Summary

The density of available bone in an edentulous site is a determfactor in

Treatment planning,

Implant design,

Surgical approach,

Healing time,

And initial progressive bone loading


24/24

Summary

A key determinant for clinical success is the diagnosis of boin a potential implant site

The strength of bone is directly related to bone density

bone density 4

Documents