Dr. Akshey Sharma
Dr. Rajesh Bhanot
Dr. Pardeep Bansal
Dr. Gagan Chahal
Dr. Swati Mittal
PG student 1st year
Deptt of Prosthodontics
As dentists, it is vital for us to have a complete
understanding of the general metabolism of calcium
as it helps in the formation and maintenance of the
teeth and their supporting bony structure.
Approximately 99% of the total body weight of
calcium is present in the skeleton.
The remaining 1% is found in the cell
membranes and extracellular fluid.
It is this small percentage of calcium that is vital
to all life processes.
1. Contributes to hardness of bone and is a major
component of teeth.
2. Stabilises the cell membrane and their permeability.
3. Maintenance of excitability of nerve and muscles.
4. Normal skeletal and cardiac muscle contraction.
5. Blood coagulation – Ca++ is required for the
conversion of many inactive enzymes in the
Infants (< 1 year) = 300-500 mg/ day
Children (1 – 18 years) = 0.8-1.2 g/day
Adult men and women = 800 mg/day
Pregnancy and lactation = 1.0-2gm/day
Milk is a good source for calcium. Calcium content of cow
milk is about 100mg/100ml.
Egg, fish & vegetables are medium source for calcium.
Cereals (wheat, rice) contains small amount of calcium.
But cereals are the staple diet in India. Therefore, cereals
form the major source of calcium in Indian diet.
Several different kinds of calcium compounds are used
in calcium supplements. Each compound contains
varying amounts of the mineral calcium.
Common calcium supplements may be labeled as:
Calcium carbonate - Tums® and Caltrate®
Calcium citrate- Citracal® and Solgar®
If the calcium in diet and from supplements exceeds
the tolerable upper limit, you could increase your risk
of health problems, such as:
Calcium buildup in your blood vessels
Impaired absorption of iron and zinc
Calcium absorption in the small intestine occurs by both
active & passive diffusion.
Uptake of calcium by active transport predominates in:
Simple diffusion predominates in:
Most of the ingested calcium is normally eliminated in the
feces, although the kidneys have the capacity to excrete
large amounts by reducing tubular reabsorption of calcium
VitaminD –Calcitriol induces the synthesis of the carrier protein
(Calbindin) in the intestinal epithelial cells & so facilitates the
absorption of calcium.
Parathyroid hormones increases calcium transport from the
Amino acids, especially lysine & arginine increase absorption.
Lactose : enhance passive Ca uptake; its effect is valuable because of
it presence in milk.
Phytates — Phytates are substances found in some plant foods that can bind
calcium in the intestine and decrease its absorption.
Oxalates are present in some leafy vegetables which cause formation of
insoluble calcium oxalates .
In malabsorption syndromes , fatty acid is not absorbed , causing formation
of insoluble calcium salt of fatty acid .
High phosphate content will cause precipitation as calcium phosphate.
Absorption is also decreased with increase intake of protein & fiber in diet.
This term is used to describe the amount of Ca++
either stored or lost by the body over a specific period
When the assimilation of calcium from dietary sources
is less than the metabolic requirements and the
obligatory losses , then calcium is withdrawn from the
skeleton to maintain the critical concentration of the
element in the blood and tissue fluids.
Calcium homeostasis is the mechanism by which
the body maintains adequate calcium levels.
Positive Ca2+ balance
Is seen in growing children, where intestinal Ca2+
absorption exceeds urinary excretion and the
difference is deposited in the growing bones.
Negative Ca2+ balance
Is seen in women during pregnancy or lactation,
where intestinal Ca2+ absorption is less than
urinary excretion and the difference comes from
the maternal bones.
The primary source of available calcium is trabecular
bone, not cortical bone.
The sites of trabecular bone which supply mobile
calcium are the jaws, ribs, bodies of the vertebrae, and
the ends of the long bones.
A significant finding from animal experimentation is
that, when skeletal depletion of calcium occurs as a
result of stimulation of the parathyroid gland, alveolar
bone is affected first, the ribs and the vertebrae are
affected second, and the long bones third.
Prolonged depletion results in disorganization and
loss of trabeculae, followed by cortical remodeling or
A complex set of interlocking mechanisms takes place
in order to allow man to survive major dietary Ca
intake fluctuations. These mechanisms are mainly
controlled by the endocrine systems.
Three main hormones acting at 3 different sites are
responsible for Ca metabolism.
1. Vit. D3 - Bone.
2. Parathormone - Kidney
3. Calcitonin - Intestine
Physiologically active form of vitamin D is a hormone
called calcitriol or 1,25 – dihydroxycholecalciferol
(1,25 – DHCC).
It stimulates Ca uptake by osteoblasts of the bone and
promotes calcification or mineralization and
remodelling , thus increasing the blood calcium
The prime function is to elevate the serum calcium
Action on kidney – increases Ca reabsorption by
Action on bone – decalcification or demineralization
of bone – increase blood Ca levels.
Promotes calcification by increasing activity of
Decreases bone resorption.
Increases excretion of Ca in urine.
Thus, has a decreasing influence on blood Ca.
Estrogen is a hormone that plays an important role in
helping increase calcium absorption.
After menopause, estrogen levels drop and so may
Hormone replacement therapy has been shown to
increase the production of vitamin D thus increasing
Hypercalcemia - Increased level of Ca in the blood.
- Loss of appetite.
- Nausea, vomitting.
Conditions in which it occurs
- Acute osteoporosis.
- Vit. D intoxication.
- Loss of muscle tone.
- Decreased excitability of
muscles and nerves.
Hypocalcemia - Decreased levels of Ca in the blood.
Below 8.8mg/dl mild tremors
Less than 7.5mg/dl tetany
- Tetany (Carpopedal spasm).
This occurs in cases of –
- Insufficient Ca in the diet.
- Insufficient vit. D in the diet.
- Increase in calcitonin levels.
Osteoporosis is the most common of all bone diseases in adults,
especially in old age.
It results from diminished organic bone matrix rather than from
poor bone calcification.
In osteoporosis the osteoblastic activity in the bone usually is
less than normal, and consequently the rate of bone osteoid
deposition is depressed.
Characterized by demineralization of bone resulting in
progressive loss of bone mass.
Elderly persons (>60 years) of both sexes are at risk.
More predominantly in postmenopausal women.
Etiology – ability to produce calcitriol from vitamin D
is reduced with age.
Results in frequent bone fractures – major cause of
The spine, hips, ribs, and wrists are common areas of
bone fractures from osteoporosis although
osteoporosis-related fractures can occur in almost any
Osteoporosis can be present without any
symptoms for decades because osteoporosis
doesn't cause symptoms until bone fractures.
Therefore, patients may not be aware of their
osteoporosis until they suffer a painful fracture.
The symptom associated with osteoporotic
fractures usually is pain; the location of the pain
depends on the location of the fracture.
Repeated spinal fractures can lead to chronic lower
back pain as well as loss of height and/or curving
of the spine due to collapse of the vertebrae.
Osteoporosis can be described as a lack of bone density or
poverty of bone tissue.
Many patients exhibit continuing bone resorption under
well-made dental prostheses.
These patients return with complaints of discomfort and
inability to tolerate their prostheses, showing rapid,
inexplicable bone loss.
Most of these patients are postmenopausal women.
There are many systemic factors which contribute to
alveolar bone loss and decreased ability to tolerate
Osteoporosis should always be considered as a
The condition of osteoporosis results in bone loss in the
maxillae and mandible as well as in other bones of the
Studies have shown that nutritional supplementation
can yield impressive results.
Albanese used a supplement of 750 mg of calcium per
day over a 3-year period and found that the
supplemented patients showed cessation of bone loss
or an increase of up to 12% in bone density when
compared to a test group showing continued bone
Jowsey suggests calcium supplementation of 1,000
Wical and Brussee treated patients with 750 mg of calcium
per day for 1 year.
When compared to a similar
nonsupplemented group, the reduction of bone loss was an
impressive 34% in the maxillae and 39% in the mandible.
In contrast, several studies reported no benefit to bone
density from daily calcium supplementation.
Calcium metabolism and
osteoporotic ridge resorption
R. P. Blank, H. A. Diehl, G. T. Ballard, and R. C. Melendez (JPD NOV 1987)
Osteoporosis may be defined simply as a condition of
This deficiency undermines skeletal strength, resulting in
fractures that occur with minimal stress in the spine, distal
radius and ulna, and in the femoral neck.
Of the 190,000 hip fractures occurring annually, 80% are in
The relationship of osteoporosis to alveolar and
residual ridge resportion is of justifiable concern to the
Although generalized bone loss is characteristic of
osteoporosis, the first sign may be alveolar bone loss,
followed by loss in the vertebrae and long bones.
It may be difficult to treat edentulous patients who
manifest the excessive residual ridge resorption often
associated with osteoporosis.
By the time osteoporosis is generally diagnosed, 50%
to 75% of the original bone material has been lost from
Increasing calcium intake by means of dairy foods and
supplementation is the method most practiced in the
prevention and treatment of osteoporosis to optimize
Studies indicate protection against age-related bone
loss in the hand bones and residual ridge bone with
increased calcium intake.
In contrast, several studies reported no benefit to bone
density from daily calcium supplementation.
This variance in reported data helps to explain the
wide range in recommended dietary calcium intake
from various health organizations.
The current recommended dietary allowance (RDA) is
800 mg of calcium/day,
The most recent National Institutes of Health (NIH)
proposal calls for 1000 to 1500 mg of daily calcium.
The World Health Organization (WHO)
recommendation is only 400 to 500 mg of
Calcium intake in most populations around the
world is 300 to 500 mg/day without any evidence
Bone resorption of residual ridges is common. The rate
of resorption varies among different individuals and
within the same individual at different times.
Factors related to the rate of resorption are divided
into anatomic, metabolic, functional, and prosthetic
Anatomic factors include the size, shape, and density
of ridges, the thickness and character of the mucosa
covering, and the ridge relationships.
Metabolic factors include all of the multiple
nutritional, hormonal, and other metabolic factors
which influence the relative cellular activity of the
boneforming cells (osteoblasts) and the bone
resorbing cells (osteoclasts).
Functional factors include the frequency, intensity,
duration, and direction of forces applied to bone
which are translated into cellular activity, resulting in
either bone formation or bone resorption.
Prosthetic factors include the myriad of techniques,
materials, concepts, principles, and practices which
are incorporated into the prostheses.
Although the various factors can
be divided into these four groups for academic
purposes, they are all interrelated.
The diets of subjects with minimal bone resorption
were compared with the diets of subjects with severe
The results indicate a positive correlation among low
calcium intake, and severe ridge resorption.
Emphasis was placed on the importance of considering
dietary factors in the diagnosis and treatment of
prosthodontic problems which arise from the excessive
resorption of residual ridges.
It was concluded that systemic conditions are
important in the etiology of residual ridge resorption.
The resistance of bone to mechanical stresses depends
on its physiologic state.
Of the many systemic influences which affect the bone
responses of patients, dietary factors may be subject to
the dentist’s control just as are factors of denture
Nutritional deficiencies and imbalances, as well
as mechanical factors, should receive
consideration in diagnosis and treatment
planning for prosthodontic patients.
Biochemistry U. Satyanarayan
Sheldon Winkler ,A.I.T.B.S. Publishers , Essentials of
complete denture Prosthodontics,2nd edition
Relationship of osteoporosis to excessive residual ridge
resorption ; J. Crystal Baxter (JPD July 1974)
Calcium metabolism and osteoporotic ridge resorption
R. P. Blank, H. A. Diehl, G. T. Ballard, and R. C.
Melendez (JPD Nov 1987)
Some clinical factors related to rate of resorption of
residual ridges ; Atwood (JPD Aug 2001)
Studies of residual ridge resorption. The
relationship of dietary calcium and phosphorus to
residual ridge resorption ; Wical and Swoope (JPD July