The document discusses bone decalcification, a process that removes calcium ions to make bones flexible for pathological investigations. It outlines various methods of decalcification, including traditional methods, acid decalcifying agents, ion exchange resins, electrolytic decalcification, and chelating agents like EDTA. Additionally, it describes the purpose, principles, and ways to test for the completion of decalcification.

1. HENRY MOORE
NO ONE EVER KNOWS
WHAT EACH DAY IS GOING
TO BRING . THE IMPORTANT
THING IS TO BE OPEN AND
READY FOR IT.

2. UNIVERSITY FOR
DEVELOPMENT
STUDIES

3. BONE
DECALCIFICATION.
• Presented by;
• Group three
• Nursing(LEVEL 100)

4. Calcium ions found in the bones are responsible
for its rigid posture and without it, bones may be
flexible and most of time unable to carry their
body weight. Diseases such as osteomalacia and
rickets are as a result of lack of calcium in the
bones of those areas.
De-calcification of bones as our topic is about the
removal of these calcium from the bones. As
such, we are going to look at the following about
the topic:
•The definition of decalcification of bones
•The purpose of decalcification of bones
•The principle of bone decalcification
•The method of decalcification of bones
How to test for the completion of decalcification

5. INTRODUCTION
Decalcification
Loss of calcium salts from a bone or tooth.
OR
The process of removing calcareous matter.
Bone decalcification
Removal of calcium ions from the bone
through histological process thereby making
the bone flexible and easy for pathological
investigation.

6. PURPOSE OF BONE DECALCIFICATION
• The purpose is to make the bone flexible
and easy for pathological investigation.
This is necessary in order to obtain soft
sections of the bone using the microtome
• Failure to decalcification results in torn,
ragged sections and damage to the
cutting edge of the microtome knife

7. PRINCIPLE OF DECALCIFICATION
• Insoluble calcium salt are converted into
soluble calcium salts by the action of
decalcifying agent so that the tissue
become soft.
• Chelating agent binds to calcium ions
present in the bone and decalcification is
carried out.

8. Methods of decalcification
• Traditional method
• Acid decalcifying agents.
• Ion exchange resins with acid and
decalcifying fluids.
• Electrolytic decalcification.
• Chelating agents.

9. TRADITIONAL METHOD
• There is a traditional method of handling hard
tissues such as bones ,but it posses problems to
both pathologists and histotechnologists.
• This is because ,it involves a lot of cutting of the
tissue and keeping them for long periods in
decalcifying solutions and this makes it difficult to
get the cellular details intact.

10. Acid decalcifying agent
• Acids are further divided into two
namely : weak acids and strong
acids.
• Weak ( Picric, Acetic and Formic
acid)
• Strong (Nitric and Hydrochloric
acid)

11. Nitric acid
MEHTOD
Thin slices of fixed tissue are placed in
a freshly prepared 5-10% solution of
nitric acid in distilled water.
Decalcification through this should not
extend beyond 48 hours.
Formalin is added to nitric acid to
protect the tissue against maceration
and swelling.

12. Formic acid
• Formic acid is widely used as a
decalcifying agent.
• For routine 10% of formic acid in distilled
water is recommended and higher
concentration gives more rapid
decalcification.
• A large volume of fluid is used and
renewed every 48 hours.

13. Ion exchange resins with acid
decalcifying fluids
It is an advanced system that quickly
remove calcium from bone while
leaving superior cellular details intact.
Electrolytic Decalcification
It is the speedier decalcification without
damage to cytological features and
staining.
Drawback:
Heat produced in the process may cause
the charring of specimen in the process

14. Chelating Agents
• EDTA is a chelating agent, it is a white
crystalline powder soluble in distilled
water to about 20%.
• As a decalcifying agent it combines
with calcium ions to form soluble, non
ionized compounds.
• The volume of solution for decalcifying
should be 150 times that of the tissue.
• The solution should be renewed every
5 to 7 days during decalcification.

15. Advantages of EDTA
• Deposits of iron and other metals may also
be removed by EDTA.
• Tissue is not hardened after decalcification.
• It can be good for Bone ,Teeth and any
calcified tissue.
• This is also the preferred solution for
decalcifying bone material for transmission
electron microscopy .

16. Test for completion of Decalcification
There are three methods for determining
the completion of progress of
decalcification.
 By X-ray examination.
 By Ammonia method(chemical method).
 By Physical method

17. X-ray Examination
• The most reliable method for
determining decalcification.
• But as this facility is not present
in all the laboratories

18. Ammonia Method
• In this method ammonia is added drop
by drop in the decalcifying solution
cloudiness indicate the presence of
calcium.
• The specimen is then placed in a fresh
solution of decalcifying fluid and test
is repeated after a suitable interval of
time.

19. PHYSICAL METHOD
• This include bending the specimen or inserting a
pin, razor or scalpel directly into the tissue.
• The disadvantage of inserting a pin is introduction
of tears and pinhole or artifacts.
• Slightly bending is less disruptive but will not
conclusively determine if all calcium salts have
been removed.
• After checking for rigidity, wash thoroughly prior to
processing.

20. DIAGRAM OF A DECALCIFIED BONE.

21. SUMMARY

22. BONE DECALCIFICATION
Removal of calcium ions from the bone through
histological process thereby making the bone
flexible and easy for pathological investigation.
Methods;
 Acid decalcifying agents
 Traditional method
 Ion exchange resins with acid and decalcifying
fluids.
 Electrolytic decalcification
 Chelating agents

23. QUOTE :
THE ONLY WAY TO DISCOVER THE LIMIT
OF THE POSSIBLE IS TO GO BEYOND
THEM INTO THE IMPOSSIBLE.