Calcium and phosphorus metabolism / dental implant courses by Indian dental academy

CALCIUMAND
PHOSPHATEMETABOLISM
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.com

CONTENTS
Introduction
Calcium and phosphorous distribution in the body
Sources of calcium and phosphorus
Daily requirements
Functions of calcium and phosphorus
Absorption of calcium and phosphorus-factors affecting
Vitamin D and its role in Calcium and phosphate
metabolism
Role of PTH in Calcium and phosphate metabolism
Influence of other hormones
Calcium concentration,bone and osteoporosis
Disorders of calcium and phosphate metabolism
Prosthodontic Implications
Summary and conclusion
References www.indiandentalacademy.com

INTRODUCTION
The rigidity of the skeleton which provides support and
protection for soft tissues,muscle contraction,the hardness
and fitness of teeth,the stability of cell membranes,
activation of many hormones and last but not the least the
heart beat itself is dependent on the twin minerals of the
body –Calcium and phosphorus.Together,whether in
ionized or unionized form,they are arguably two of the most
important body components.

IMPORTANCE AND DISTRIBUTION OF
Ca++
IN THE BODY
The human body contains about 1kg of Ca++
of which 99% is in
the skeleton and remaining 1% in soft tissues and ECF (990gms)
and (10gms).
of 990 gms in the skeleton
- 10 gms forms the readily exchangeable Ca++
pool of bone
(MISCIBLE POOL)
- 980 gm  slow exchange of Ca++
takes place (STABLE
POOL)
10.0-10.5mg/dl NORMAL SERUM CALCIUMLEVEL
Remaining in soft tissues
Diffusible/ ultra filterable form 5.5mg/dl
Non-diffusible / protein bound form 4.5mg/dl
Ionized Ca 5.0mg/dl
Bound to PO4
, HCO3
, Citrate 0.5mg/dl
Bound to albumin 4.0mg/dl
Bound to globulin 0.5mg/dlwww.indiandentalacademy.com

tmj13.JPG

FUNCTIONS OF CALCIUM
1. Contributes to hardness of bone and is a major
component of teeth.
2. Stabilizes the cell membrane and their
permeability.
3. Maintenance of excitability of nerve and muscles.
4. Normal skeletal and cardiac muscle contraction.
5. Helps in the neurotransmitter release.
6. Secretion of granular material from exocrine and
endocrine glands.
7. Hormone release and activity – discharge of non-
adrenaline in the nerve terminal cell.
8. Synthesis of nucleic acid and protein.
9. Blood coagulation – Ca++
is required for the
conversion of many inactive enzymes in the coagulation

DAILY REQUIREMENTS OF CALCIUM
(WHO ESTIMATE)
The recommended dietary allowance (R.D.A) for
calcium is 0.5 –0.8 gms/day
6 months – 2 year = 0.5-0.6 g/day
16 years to adults = 0.5-0.6g/day
Pregnancy and lactation = 1.0-2gm/day
Children = 800mg/day

SOURCES OF CALCIUM
- Milk + milk products.
- Egg.
- Meat
- Fish
- Leafy vegetables Eg.Cauliflower
- Vegetables Eg.Beans
- Fruits Eg.Oranges
- Nuts.Eg.Almond,peanuts
- Bread(fortified)
- Hard water

PHOSPHOROUS
DISTRIBUTION OF PHOSPHOROUS IN THE
BODY
- The human body contains 500-600 gms of PO4
--
out
of which 85% (425g) is in the bone.
- Remaining phosphorous is present in the liver,
pancreas and brain.
- Phosphorous is essential for the formation of teeth.
Normal serum PO4
--
level is 2.5 – 4.5 mg/dl.
Serum inorganic form
3-4 mg/dl in adults
5-6mg/dl in children
Organic phosphorous
Remaining in the form of
phospholipids &
glycerophosphates

FUNCTIONS OF PHOSPHOROUS
1. Formation of bone and teeth. It is the
essential constituent of all cells.
2. Important constituent of high energy
phosphate compounds like ATP, creatine
phosphate, cyclic AMP, hexose phosphate, 2-
3DPG, phospholipids, nucleotides.
3. Helps in the regulation of glycolysis.
4. Phosphorylation of lipids and sugar i.e.
absorption, transportation and metabolism.
5. Urinary buffer, which regulates urinary pH.
DAILY REQUIREMENTS OF PHOSPHOROUS – 1gm/day

CONCEPT OF CALCIUM BALANCE
This term is used to describe the amount of Ca++
either stored or lost by the body over a specific
period of time. This can be calculated by
deducting the amount of Ca in the urine from the
Ca taken in the diet.
Ca in diet - Ca in faeces  Ca absorbed – Ca
in urine
Ca lost / gained
e.g., If 1.0gm Ca is in the diet – 0.7 gm in fasces
 0.3g absorbed. 0.1g net gain  0.2g in urine

The Ca balance values are said to change with age.
In a growing child, there is a Net gain for growing and
mineralizing skeleton.
In an aging adult, there is a Net loss as Ca from bone is lost
too due to conditions like osteoporosis. Hence, amount of
Ca lost is greater than Ca in intake.

ABSORPTION OF CALCIUM AND
PHOSPHOROUS
It is seen that almost all the food taken in the diet is
almost completely absorbed in the gut whereas the amount
of minerals absorbed is very negligible.
This could be due to the various factors affecting the
absorption of Ca++
and PO4
--
.
The factors can be studied under:
Factors affecting mucosal cell
Factors influencing Ca absorption in the gut

FACTORS AFFECTING MUCOSAL CELL
Vitamin D and Calcium Absorption
Effect of previous Calcium intake and of increased
calcium need
Effect of pregnancy and Growth

FACTORS AFFECTING CALCIUM
ABSORPTION IN THE GUT
Parathyroid hormone
Effect of pH of the intestine
The amount of dietary calcium and phosphorus and the
Ca:P ratio
Phytic acid and Phytates
Effect of Oxalates
Influence of Fat on calcium absorption
Effect of protein and amino acids
Effect of carbohydrates
Seasonal effect

VITAMIN D AND ITS ROLE IN CALCIUM
AND PHOSPHATE METABOLISM
Vitamin D has a potent effect on
Increasing Ca absorption from the intestinal tract
Effects on both bone deposition and resorption
Vitamin D is itself not the active substance.Instead it
must be converted through a succession of reactions in
the liver and kidney to the final active product 1,25-
Dihydroxycholecalciferol.

ROLE OF PARATHYROID HORMONE ON
CALCIUM AND PHOSPHATE
METABOLISM
Increased activity of the Parathyroid (PT) gland causes
rapid absorption of Ca salts from the bones with the
resultant hypercalcaemia an extracellular fluid.Conversely
hypofunction of the PT glands cause hypocalcaemia
Rise in calcium concentration is caused
principally by :
Rise in calcium and phosphate absorption from the bone
A rapid effect in decreasing the excretion of Ca by
kidneys

The decline in phosphate concentration is caused by the
effect of PTH in causing excessive phosphate excretion
Ca AND P ABSORPTION FROM BONE CAUSED BY
PARATHYROID HORMONE
It occurs in two phases:
Rapid phase:Osteolysis
Slow phase:Activation of Osteoclasts
EFFECT OF PTH ON Ca AND P EXCRETION BY THE
KIDNEYS
EFFECT OF PTH ON INTESTINAL ABSORPTION OF
Ca AND P

EFFECT OF Ca ION CONCENTRATION ON PTH
SECRETION

ROLE OF CALCITONIN IN THE REGULATION OF
CALCIUM ION CONCENTRATION
Calcitonin is a peptide hormone secreted by the thyroid
gland (Parafollicular or ‘C’ cells)
It tends to decrease plasma Ca ion concentration and has
effects opposite to those of PTH
Increased Ca ion concentration stimulates Calcitonin
secretion which then reduces Ca ion conc. of the plasma

OTHER HORMONES THAT EFFECT CALCIUM
METABOLISM
Growth Hormone
Insulin
Testosterone
Estrogen
Prolactin
Thyroid hormone[T3 and T4]
Steroids

REGULATION OF CALCIUM ION
CONCENTRATION IN BONE AND
OSTEOPOROSIS
99% of body’s calcium is found in the skeleton
Bone deposition and resorption go on concurrently
Bone has three types of cells:
Osteoblasts
Osteocytes
Osteoclasts
PTH uses bone as a “bank” from which it withdraws Ca
as needed to maintain the plasma Ca level

OSTEOPOROSIS: THE BANE OF BRITTLE
BONES
Osteoporosis is a decrease in bone density resulting from
reduced deposition of the bone's organic matrix
The condition is especially prevalent in post menopausal
women.
After menopause women start losing 1% or more of bone
density every year
Because bone mass is reduced, the bones are more
susceptible to fracture.
There are two types of Osteoporosis:
TYPE I
TYPE II
Treatment:
Estrogen replacement therapy
Ca supplementation

EXCRETION OF CALCIUM AND PHOSPHORUS
Ca is said to be excreted both in the faeces and in the
urine.About 90% of the total amount of Ca is excreted in
the faeces.
Calcium of the urine is excreted as Calcium chloride and
Calcium phosphate.
The approximate daily turnover rates of Calcium in an
adult are as follows:
Intake :1000mg
Intestinal absorption :350mg
Secretion in GI juices :250mg
Nett absorption over secretion :100mg
Loss in the faeces :200mg
Excretion in the urine :100mg

Phosphorus is excreted primarily through the urine.
Almost two thirds of total phosphorus that is excreted is
found in the urine as phosphate of various cations.
Phosphorus found in the faeces is the non absorbed form
of phosphorus

DISORDERS OF CALCIUM AND PHOSPHATE
METABOLISM
It can be studied under the following headings:
Hypercalcemia
Hypocalcaemia
Hyperphosphataemia
Hypophosphataemia

Hypercalcemia
Causes:
With normal or elevated PTH levels:
Primary or tertiary hyperparathyroidism
Lithium induced hyperparathyroidism
Familial hypocalciuric hypercalcemia
With low/suppressed PTH levels:
Malignancy
Multiple myeloma
Elevated 1,25DHCC
Thyrotoxicosis
Paget’s disease
Milk alkali syndrome
Thiazide diuretics

CLINICAL FEATURES OF HYPERCALCEMIA
“Bones,Stones and abdominal groans”
Polyurea Renal calculi
Polydipsia Impaired renal function
Renal colic Acute dehydration
Lethargy Hypertension
Anorexia
Nausea
Dyspepsia
Peptic ulceration
Constipation
Depression
Drowsiness
Impaired cognitive function

INVESTIGATIONS:
Total calcium measurements……………… (Raised)
Plasma phosphate………………………….(Lowered)
Alkaline Phosphatase………………………(Raised)
Total PTH……………………….Immunoradiometric
assay
SKELETAL AND RADIOGRAPHIC CHANGES:
Osteitis fibrosa
Localized swelling{mandible-Cystic}
Chondrocalcinosis
Nephrocalcinosis
Subperiosteal erosions in the phalanges
Pepperpot appearance of the skull in lateral
cephphalograms
Cystic changes www.indiandentalacademy.com

Treatment of Malignant Hypercalcemia:

HYPOCALCEMIA
CLINICAL FEATURES:
Tetany
Carpal Spasm
Trousseau’s Sign
Chvostek’s Sign
Erb’s Sign
TREATMENT:Intravenous calcium gluconate

HYPOPHOSPHATAEMIA:
In the presence of a plasma phosphate less than 0.4
mmol/l[normal range:0.8-1.4mmol/l],wide spread cell
dysfunction and death may occur.
CLINICAL FEATURES:
Muscle pain and weakness,high levels of plasma creatine
kinase
Respiratory muscle weakness
Cardiac arrhythmias
Confusion,convulsions,coma
Haemolysis
hypercalciurea.,hypermagnesuria

HYPERPHOSPHATAEMIA
Seen in acute or chronic renal failure
Metastatic calcification
Secondary stimulation of parathyroid glands
Pruritus

SOME DISORDERS OF VITAMIN D:
VITAMIN D DEFICIENT RICKETS
In children
Mainly affects the long bones in the body and the ribs
Occurs due to the failure in the mineralization due to
lack of adequate Ca level,the cartilagenous form of bone
is said to persist
The cartilage continues to proliferate and enlarge thus
resulting in localized areas of cartilagenous proliferation
in the form of RICKETY ROSARY,BEADED BONE
FORMATION.

The weight of the body on the uncalcified long bones
result in bowing of legs-KNOCK KNEES
DENTAL ABNORMALITIES:
Developmental anomalies of enamel and dentine
Delayed eruption of teeth
Malalignment of teeth
Higher caries index
Wider predent9ine zone
Increased amount of interglobular dentine
TREATMENT:
Supply adequate amounts of Ca and phosphate in diet and
administration of large amounts of Vitamin D

OSTEOMALACIA
Seen in adults
Mainly affects the flat bones of the body
Esp. seen in post menopausal women who have a
decreased dietary Ca intake and decreased exposure to the
sun resulting in increased removal of Ca from the bone
causing softening of the skeleton and its distortion
DENTAL FINDINGS:
Severe periodontitis
TREATMENT:
Ca supplement
Vitamin D supplement

PROSTHODONTIC CONSIDERATIONS:
In Paget’s disease of the bone where the maxilla exhibits
progressive enlargement the dentures may be remade
periodically to accommodate the increase in size of the jaws
In diabetic and osteoporotic patients particular attention
must be given to accurate impressions.In addition the use of
monoplane teeth in the dentures of these patients may be
advocated to minimize off vertical and horizontal forces.

Patients with Ca deficiency invariably have dental
abnormalities like missing teeth .The importance of a
meticulous case history cannot be overstressed.
The diet history of elderly edentulous and post
menopausal patients must be recorded with particular
emphasis on adequate calcium and phosphorus
supplementation.

The placement of implants demands precise evaluation of
the quality of the underlying bone.Various classifications
have been proposed.One of the most important
classification is as follows:
MISCH BONE DENSITY CLASSIFICATION:
D1:Dense cortical bone
D2:Thick dense porous cortical bone on crest and coarse
trabecular bone within.
D3:Thin porous cortical on crest and fine trabecular bone
within
D4:Fine trabecular bone.
D5:Immature non mineralized bone.

SUMMARY AND CONCLUSION
- As dentists, it is vital for us to have a complete
understanding of the general metabolism of calcium and
phosphorous as it is these minerals that help in the formation
and maintenance of the teeth and their supporting bony
structure .Two points need to be kept in mind:
1. Ca++
metabolism is a very complicated and
controversial topic on which no definite conclusion has yet
been reached, which is acceptable by all researchers.
2.I have dealt with factors affecting Calcium and Phosphate
metabolism in the body as a whole and it should not be
assumed that all these factors necessarily affect the teeth.

BIBLIOGRAPHY
•A.V.S.S.Rama Rao-Textbook of biochemistry,5th
edition
•Carl.E.Misch-Contemporary implant dentistry,2nd
edition
•David.B.Ferguson-Oral biosciences,1st
edition
•Guyton-Textbook of medical physiology,8th
edition
•G.Neil Jenkins-Physiology and biochemistry of the
mouth,4th
edition
•K.D.Tripathi-Essentials of medical Pharmacology,5th
edition

•Laurence Sherwood-Human physiology-from cells to
system,4th
edition
•Malcolm Harris Michael Edgar Sajeda Meghji-Clinical
Oral Science,1sr edition
•Robert M Berne Matthew M Lewey-Physiology,3rd
edition
•T.N.Pattabhiraman-Textbook of biochemistry,2nd
edition

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