Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Integration finals > fluoride metabolism > Flashcards

fluoride metabolism Flashcards

1
Q

importance of fluoride

A

-To form Fluorapatite (FA) (systemic)
-To form CaF2
(topical/in saliva)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

To form CaF2

topical/in saliva

A

– Coats the surface of enamel

– Enamel become less soluble, more resistant to acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

-To form Fluorapatite (FA) (systemic)

A

– Nature of fluoride ion: small, highly electronegative,
high charge density
• Allow a better fit & tightly orientated in the lattice compared
to OH
ions
• Offers greater electrostatic interaction between Ca2+ and F
than between Ca2+ and OH–

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

sources of fluoride

A

drinking water, foods, fresh drinks, dental products, dietary supplement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Drinking

water

A 
< 0.3 ppm
0.5-0.9 ppm
Climate:
Warm: low [F]
Cold: high[F]
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Foods

A 
0.2-0.5 ppm
5-15 ppm (rich)
sources :
Most food
Fish with bones e.g.
Salmon, sardine,
mackerel
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Fresh drinks

A 
0.1-1.4 ppm
1-7 ppm 
Juice, coffee &amp;
carbonated drinks
Tea
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Dental

products

A 
500 ppm, low [F]
1100-1500 ppm
>1500 ppm,high [F]
Toothpastes, mouth
rinses, dental gel
*25% of fluoride
swallowed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Inorganic salts

A

sodium fluoride, sodium monofluorophosphate, stannos fluoride, stannous hexafluorozirconate, calcium fluoride, magnesium fluoride, aluminium fluoride

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Sodium fluoride

A

solubility : 4%
Used in water fluoridation
Most used in toothpaste &
mouth rinse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

sodium monofluorophosphate

A

solubility 25%, Form used in toothpaste &

mouth rinse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

stannos fluoride

A

> 10%, Form used in toothpaste &

mouth rinse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

stannous hexafluorozirconate

A

> 24%, Highly soluble: rapidly & almost completely absorbed from
gastrointestinal tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Calcium

fluoride

A

Insoluble
(0.0016%)
less completely absorbed
& at a slow rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Magnesium

fluoride

A

Insoluble, Absorption occurs by diffusion through gut wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Aluminium

fluoride

A

Insoluble, Absorption is reduced due
to present of Ca2+
, Mg2+ &
Al3+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Fluoride Metabolism

A
  1. Main absorption takes place in stomach
  2. Transported/Distributed in plasma
  3. Body fluoride is continuously regulated by
    clearance mechanism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q
  1. Main absorption takes place in stomach
A

– Insoluble form: excreted in feces

19
Q
  1. Transported/Distributed in plasma
A

– Soluble form: goes into plasma

20
Q
  1. Body fluoride is continuously regulated by

clearance mechanism

A

– Excretion: Renal clearance

– Retention: Skeletal clearance

21
Q

Fluoride absorption

A

• Form of fluoride in stomach: > Hydrogen fluoride (HF)
H+ + F- to HF
• Properties of HF: weak acid, pKa = 3.4
• The rate of absorption increases with the acidity of gaster.
• Therefore, absorption of fluoride from sour juice is faster compare to coffee, milk
etc.

22
Q

Mechanism of absorption of Fluoride in stomach:

A
  1. Excess of H+ combine with F
    - and form HF
  2. Formation of HF create/ increase a pH
    gradient
  3. ## When pH gastric < pH extracellular, Fin the
    form of HF diffuse out across the gastric
    mucosa to the plasma
23
Q

Fluoride in the plasma & its distribution 1

A

[F]plasma reach a peak
within 15-30 min
after absorption

24
Q

Fluoride in the plasma & its distribution 2

A 
Conc. at the peak is
dependent on:
– amount consumed
– acidity of stomach
– absorption rate
– diet composition
25
Q

Fluoride in the plasma & its distribution 3

A

Reduction of [F]plasma is
due to its clearance
mechanism

26
Q

Distribution of fluoride…

A

in hard tissues, in soft tissues, plasma, body fluid

27
Q

in hard tissues

A 
– 99% fluoride in hard tissues: bones &amp; teeth
– Concentration varies
• Cancellous bones > compact bones
• Dentine &amp; bones:  age
• Enamel: high plaque covered area
low Surfaces with attrition
28
Q

• in soft tissues

A

– Absorption in the form of hydrogen fluoride (HF)

– [F]soft tissues = [F] plasma

29
Q

fluoride in plasma

A 
[Fluoride] plasma is influenced by the amount of
ingested
– Very low conc. in ionised form
• When [F] H2O = 1.0 ppm
• When [F] plasma =  1.0 micromol/L
30
Q

fluoride in body fluid

A

– [Fluoride]GCF > [Fluoride]plasma, parotid & submandibular saliva
– [Fluoride] oral is absorbed by mucosal tissues & dental
plaque to released into saliva to into gastrointestinal
tract

31
Q

Clearance Mechanism.

A

skeletal clearance, renal clearance

32
Q

skeletal clearance

A

Deposition of fluoride to bone (calcified tissues)
occurs at fast rate.
-50% Fluoride is absorbed
Gets deposited within 24 hours
50% of absorbed
fluoride is excreted
in urine
Continues until the equilibrium is reached
(Return to normal after 36 hrs after ingestion)

Note: Hard tissues are reservoir for fluoride

33
Q

renal clearance

A 
Rate of renal clearance
– adult 35 ml/min (FAST)
– infant < 12 ml/min (SLOW)
• Reabsorption of fluoride occurs
at the renal tubule:
– under the influence of urine pH
Very low conc. of F is excreted
out via the salivary glands back
into the oral cavity
34
Q

acid influence for renal clearance , if low phh

A

> HF > diffusion > F is reabsorbed

• < F  < remain < Fis excreted

35
Q

acid influence for renal clearance , if high ph

A

< HF < diffusion < Fis reabsorbed

• > F  > remain > Fis excreted

36
Q

• Fluoride is essential

A

-low conc. of < 1 ppm
-Not toxic if taken into the body in sufficient
amounts (fatal dose 5.0 mg NaF)
-Cations such as Ca2+, Mg2+ & Al3+ can form
complexes with fluoride
-If not in the complex form, 80-90 % fluoride from
the gaster is absorb into the plasma

37
Q

Fluoride Toxicity

A

Chronic Effects

Acute Effects

38
Q

Acute Effects

A 
(Inhibition of the enzyme
system &amp; CNS)
• Renal dysfunction
• Hypocalcemia
• Cardiovascular disorder
• Death (within 2-3 days) 
Note:
Acute toxicity of fluoride can occur after ingesting one or
more doses of fluoride over a short time period which
then leads to poisoning
39
Q

Chronic Effects

A
  • Dental fluorosis
  • Skeletal fluorosis
  • Stomach upset
40
Q

Fluorosis

A

Dental Fluorosis

Skeletal Fluorosis

41
Q

Skeletal Fluorosis

[F] = > 20 ppm

A 
Abnormality of the skeletal
bone
• Radiology data – density of
bone is higher
Prolonged exposure
• Calcification of tendons,
ligaments &amp; muscles
42
Q

Dental Fluorosis

[F] = > 2 ppm

A 
Mottled enamel
(opaque white spots / irregular
white flakes)
• Influence of F during the
organic &amp; inorganic phases of
amelogenesis
*Hypoplasia-permanent teeth
(Might be due to tetracycline
intake during pregnancy)

Notes:
Happen during tooth development
Irreversible effect

43
Q

Dental Fluorosis…How does it occurs?

A 
1. Excess of F
ions retain immature matrix
proteins (amelogenin &amp; ameloblastin)
leading to accumulation of these proteins
2. Results in incomplete crystal growth
-Wide gaps develop between enamel rods:
 cause porosity
-Less hydroxyapatite crystals formed:
 brittle enamel
44
Q

Fluorosed enamel

A

structurally weak & unable to
withstand pressure thus prone to breakage
Difficult for dental procedures which require drilling
& filling

Integration finals (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions