Content uploaded by Ana Maria Trindade Grégio
Author content
All content in this area was uploaded by Ana Maria Trindade Grégio
Content may be subject to copyright.
1
The Journal of
C
ontemporar
y
Dental Practice, Volume 9, No. 3, March 1, 2008
Saliva Composition and Functions:
A Comprehensive Review
Aim:
The aim o
f
this stud
y
was to per
f
orm a literature review about the composition and
f
unctions o
f
saliva as
w
ell as describe the factors that influence salivar
y
flow (
S
F) and its biochemical composition
.
B
ack
g
round
:
S
aliva represents an increasin
g
ly useful auxiliary means of dia
g
nosis.
S
ialometry and
sialochemistry are used to diagnose systemic illnesses, monitoring general health, and as an indicator o
f
risk
f
or
d
iseases creatin
g
a close relation
b
etween oral an
d
systemic
h
ealt
h.
R
ev
i
ew
:
This review provides
f
undamental in
f
ormation about the salivar
y
s
y
stem in terms o
f
normal values
f
or
S
F and composition and a comprehensive review of the factors that affect this important s
y
stem
.
C
onclusion
:
S
ince several factors can influence salivar
y
secretion and composition, a strictl
y
standardized
c
ollection must be made so the above-mentioned exams are able to re
f
lect the real
f
unctionin
g
o
f
the salivary
g
lands and serve as e
ff
icient means
f
or monitorin
g
health
.
C
linical Si
g
nificance:
S
ince many oral and systemic conditions manifest themselves as chan
g
es in the flow
a
nd composition o
f
saliva the dental practitioner is advised to remain up-to-date with the current literature on
t
h
e su
b
ject
.
K
e
y
words
:
S
aliva, salivary
g
lands, salivary proteins, lysozyme, lactoferri
n
C
itation: de Almeida PDV, Gré
g
io AMT, Machado M
Â
N, de Lima AAS, Azevedo LR. Saliva Composition and
Functions: A Comprehensive Review. J Contemp Dent Pract 2008 March; (9)3:072-080
.
Abstract
2
The Journal of
C
ontemporar
y
Dental Practice, Volume 9, No. 3, March 1, 2008
Introduction
S
alivar
y
fluid is an exocrine secretio
n
1,2
cons
i
st
i
n
g
o
f
approximately 99% water, containin
g
a variety o
f
electrol
y
tes (sodium, potassium, calcium, chloride,
ma
g
nesium, bicarbonate, phosphate) and proteins,
r
epresente
d
b
y enzymes, immuno
g
lo
b
ulins an
d
other antimicrobial
f
actors, mucosal glycoproteins,
traces o
f
albumin and some pol
y
peptides and
oli
g
opeptides o
f
importance to oral health. There
a
re also glucose an
d
nitrogenous pro
d
ucts, suc
h
a
s urea an
d
ammonia
.
3,4
T
h
e components interact
a
nd are responsible
f
or the various
f
unctions
a
ttri
b
ute
d
to
s
aliva
.
2
Total or whole saliva re
f
ers to the complex mixture
o
f
f
luids
f
rom the salivary glands, the gingival
f
old,
oral mucosa transudate
,
in addition to mucous o
f
t
h
e nasal cavit
y
an
d
p
h
ar
y
nx, non-a
dh
erent oral
bacterial,
f
ood remainders, desquamated epithelial
a
nd blood cells
,
as well as traces o
f
medications or
c
h
emical pro
d
ucts
.
3
-9
A
t rest, wit
h
out exo
g
enous or p
h
armacolo
g
ical
s
timulation, t
h
ere is a small, continuous salivar
y
f
low (
S
F), denominated basal unstimulated
s
ecretion, present in the
f
orm o
f
a
f
ilm that covers,
moisturizes
,
an
d
lu
b
ricates t
h
e oral tissues.
Wh
ereas, stimulate
d
saliva is pro
d
uce
d
in t
h
e
f
ace o
f
some mechanical,
g
ustatory, ol
f
actory, or
p
h
armacolo
g
ical stimulus, contri
b
utin
g
to aroun
d
8
0% to 90% o
f
dail
y
salivar
y
production
.
2
-4,9-1
2
A
h
ealt
hy
person’s mean
d
ail
y
saliva pro
d
uction
r
anges
f
rom 1 to 1.5L
.
4
The
S
F index is a
parameter allowin
g
stimulate
d
an
d
unstimulate
d
s
aliva
f
low to be classi
f
ied as normal
,
low
,
or
ver
y
low (h
y
posalivation)
.
8
In a
d
ults
,
normal
total stimulated
S
F ran
g
es from 1 to 3 mL/
min, low ran
g
es
f
rom 0.7 to 1.0 mL/min, while
h
y
posalivation is characterized b
y
a
S
F of less
than 0.7 mL/min. The normal unstimulated
S
F
r
an
g
es
f
rom 0.25 to 0.35 mL/min, low ran
g
es
f
rom 0.1 to 0.25 mL/min, while h
y
posalivation
is characterized b
y
a
S
F of less than 0.1 mL/
m
i
n
.
8,
1
1
However
,
the values denominated “normal”
f
or stimulated and unstimulated
S
F exhibit a
l
ar
g
e biolo
g
ical variation. Thus, individual
S
F
must
b
e monitore
d
re
g
ularly an
d
not
d
etermine
d
a
s
“
normal” or
“
abnormal”, based onl
y
on one
measuremen
t.
9,
11
S
aliva is critical for preserving and maintaining
the health o
f
oral tissues and has been used as a
s
ource o
f
non-invasive investi
g
ation o
f
metabolism
a
nd the elimination o
f
many drugs. However, it
r
eceives little attention until its quantit
y
d
iminis
h
es
or its qualit
y
b
ecomes altere
d.
4,
7
,
11
,
13
A
t present, saliva represents an increasin
g
ly
u
se
f
ul auxiliary means o
f
dia
g
nosis
.
14
Man
y
r
esearchers have made use o
f
sialometr
y
and
s
ialoc
h
emistry to
d
ia
g
nose systemic illnesses,
monitorin
g
g
eneral health, and as an indicator o
f
r
isk
f
or diseases creating a close relation between
oral an
d
s
y
stemic
h
ealt
h.
15
However
,
since several
f
actors can in
f
luence salivar
y
secretion and
composition a strictl
y
stan
d
ar
d
ize
d
collection must
b
e ma
d
e so t
h
e a
b
ove-mentione
d
exams are a
b
le
to re
f
lect the real
f
unctionin
g
o
f
the salivary
g
lands
a
nd serve as an e
ff
icient means
f
or monitoring
health. There
f
ore
,
the aim o
f
this literature review
w
as to investi
g
ate the composition and
f
unctions
o
f
s
aliva a
s
well a
s
de
s
cribe the
f
actor
s
that
influence
S
F and its biochemical composition
.
Saliva Functions and Composition
Taste
The
S
F initiall
y
formed inside the acini is
isotonic wit
h
respect to plasma. However, as it
r
uns throu
g
h the network o
f
ducts, it becomes
hy
potonic
.
6,9,16,17
The h
y
potonicit
y
of saliva (low
l
evels of
g
lucose, sodium, chloride, and urea)
a
nd its capacit
y
to provide the dissolution o
f
s
u
b
stances allows t
h
e gustatory
b
u
d
s to perceive
different flavors. Gustin, a salivar
y
protein,
a
ppears to be necessary
f
or the
g
rowth and
maturation o
f
the
s
e bud
s.
1
,
4
,13,1
8
3
The Journal of
C
ontemporar
y
Dental Practice, Volume 9, No. 3, March 1, 2008
Buffer Capacity
S
aliva behaves as a buffer s
y
stem to protect the
m
o
ut
h
8,
19
as
f
ollows:
1. It prevents colonization
by
potentiall
y
pat
h
o
g
enic microor
g
anisms
b
y
d
enyin
g
t
h
em
o
ptimization o
f
environmental conditions
.
2.
S
aliva buffers (neutralizes) and cleans
t
h
e aci
d
s pro
d
uce
d
b
y aci
d
o
g
enic
microor
g
anisms, t
h
us, preventin
g
enamel
de
min
e
ralizati
o
n
.
13
It is important to emphasize bio
f
ilm thickness,
a
nd the number o
f
bacteria present determines
the e
ff
icac
y
o
f
salivar
y
bu
ff
ers
.
4
N
egatively loa
d
e
d
resi
d
ues on t
h
e salivary
proteins work as buffers.
S
ialin, a salivar
y
pepti
d
e, plays an important role in increasin
g
the bio
f
ilm pH a
f
ter exposure to
f
ermentable
car
b
o
hyd
rates
.
8,
1
3
U
rea is another bu
ff
er present in total salivar
y
f
luid which is a product o
f
aminoacid and
protein cata
b
olism t
h
at causes a rapi
d
increase
in bio
f
ilm pH by releasing ammonia and
car
b
on
d
ioxi
d
e w
h
en
hyd
rol
y
ze
d
by
b
acterial
u
reases
.
3,
5
,
8
,
9
,
24
,
2
5
C
hildren with chronic renal
insu
ff
icienc
y
present with less caries than
health
y
children, due to the increased levels o
f
s
a
li
var
y
urea
.
2
6
A
mmonia, a product o
f
urea and aminoacid
meta
b
olism, is potentially cytotoxic to
g
in
g
ival
tissues. It is an important
f
actor in the initiation
o
f
g
in
g
ivitis because it may increase the
permeabilit
y
o
f
the sulcular epithelium to other
toxic or antigenic su
b
stances in a
dd
ition to t
h
e
f
ormation o
f
dental calculus
.
2
7
T
h
e car
b
onic aci
d
-
b
icar
b
onate s
y
stem is t
h
e
most important bu
ff
er in stimulated saliva, while
in unstimulate
d
saliva it serves as t
h
e p
h
osp
h
ate
bu
ff
er s
y
stem
.
8
Integrity of Tooth Enamel
S
aliva plays a fundamental role in maintaining
the physical-chemical inte
g
rity o
f
tooth
enamel
b
y mo
d
ulatin
g
remineralization an
d
demineralization. The main
f
actors controlling
the stabilit
y
o
f
enamel h
y
drox
y
apatite are the
a
ctive concentrations
f
ree o
f
calcium, phosphate,
a
nd
f
luoride in solution and the salivar
y
pH
.
1
1,28
Protection and Lubrication
S
aliva forms a seromucosal covering that
l
u
b
ricates an
d
protects t
h
e oral tissues a
g
ainst
i
rr
i
tat
i
n
g
a
g
ents
.
18,
19
T
h
is occurs
d
ue to mucins
(proteins with high carbohydrate content)
r
esponsible
f
or lubrication, protection a
g
ainst
deh
y
dration, and maintenance o
f
salivar
y
visco
-
elasticit
y
. T
h
e
y
also selectivel
y
mo
d
ulate t
h
e
a
dhesion o
f
microor
g
anisms to the oral tissue
s
ur
f
aces
,
which contributes to the control o
f
bacterial and
f
ungal colonization. In addition, they
protect t
h
ese tissues a
g
ainst proteolytic attacks
b
y microor
g
anisms. Mastication, speec
h
, an
d
deglutition are aided by the lubricant e
ff
ects o
f
t
h
ese proteins
.
1,
4
,
8
,
19-
22
Dilution and Cleaning
S
u
g
ars in their free form are present in total
s
timulate
d
an
d
unstimulate
d
saliva at a mean
concentration o
f
0.5 to 1 mg/100mL
.
3
,
5
Hig
h
concentrations o
f
su
g
ar in saliva mainly occur a
f
ter
th
e
intak
e
of
food
an
d
d
rink
.
3,
5
It is known t
h
ere is
a
correlation
b
etween t
h
e glucose concentration in
the blood and salivar
y
f
luid, particularl
y
in diabetics,
but because this is not always si
g
ni
f
icant, saliva is
not used as a means o
f
monitoring blood sugar
.
23
In addition to dilutin
g
substances, its
f
luid
consistency provides mechanical cleansing o
f
t
h
e resi
d
ues present in t
h
e mout
h
suc
h
as non
-
a
dherent bacteria and cellular and
f
ood debris.
S
F tends to eliminate excess carboh
y
drates, thus,
l
imitin
g
the availability o
f
su
g
ars to the bio
f
ilm
microor
g
anisms. The
g
reater the
S
F, the
g
reater
the cleaning and diluting capacity; there
f
ore, i
f
chan
g
es in health status cause a reduction in
S
F,
there would be a drastic alteration in the level o
f
oral cleaning
.
8,12,13,18,19
4
The Journal of
C
ontemporar
y
Dental Practice, Volume 9, No. 3, March 1, 2008
N
ormal salivar
y
pH is
f
rom 6 to 7 and varies
in accordance with the
S
F, from 5.3
(
low flow
)
to 7.8 (peak flow). There are various sources
o
f
hydrogen ions in oral
f
luids: secretion by
the salivary
g
lands in the
f
orm o
f
or
g
anic and
inor
g
anic aci
d
s, pro
d
uction
b
y t
h
e oral micro
b
iota,
or acquisition through
f
ood. These ions in
f
luence
the equilibrium o
f
calcium phosphates in the
enamel. The hi
g
her the concentration o
f
hydro
g
en
ions, t
h
e lower t
h
e pH an
d
vice versa
.
4
,
8
A
t
hi
g
her
f
lows o
f
stimulated salivary secretion, the
concentration o
f
bicarbonate ions is hi
g
her, the pH
a
lso rises, and the bu
ff
ering power o
f
the saliva
increases
d
ramaticall
y.
11
Digestion
S
aliva is responsible for the initial di
g
estion of
s
tarch,
f
avorin
g
the
f
ormation o
f
the
f
ood bolus
.
1
3
,
1
7
This action occurs mainl
y
b
y
the presence o
f
t
h
e
d
i
g
estive enzyme
α
-am
y
lase (pt
y
alin) in the
composition o
f
the saliva. Its biolo
g
ical
f
unction is
to
d
ivi
d
e t
h
e starc
h
into maltose
,
maltotriose
,
an
d
d
extrins. T
h
is enzyme is consi
d
ere
d
to
b
e a
g
oo
d
indicator o
f
properly
f
unctionin
g
salivary
g
lands
,
29
contributing 40% to 50% o
f
the total salivary
protein pro
d
uce
d
b
y t
h
e
g
lan
d
s. T
h
e
g
reater
part of this enz
y
me (80%) is s
y
nthesized in the
paroti
d
s an
d
t
h
e remain
d
er in t
h
e su
b
man
d
i
b
ular
g
lan
d
s. Its action is inactivate
d
in t
h
e aci
d
portions
o
f
the
g
astrointestinal tract and is consequently
l
imit
ed
t
o
t
he
m
o
ut
h.
3
,4,8,12,21
Tissue Repair
A
tissue repair
f
unction is attributed to saliva since
clinically the bleedin
g
time o
f
oral tissues appears
to
b
e s
h
orter t
h
an ot
h
er tissues. W
h
en saliva is
experimentally mixe
d
wit
h
b
loo
d
, t
h
e coagulation
time can be
g
reatly accelerated (althou
g
h
the resultin
g
clot is less solid than normal).
Experimental stu
d
ies in mice
h
ave s
h
own woun
d
contraction is si
g
ni
f
icantly increased in the
presence o
f
saliva due to the epidermal
g
rowth
f
actor it contains which is produced b
y
the
s
u
b
man
d
i
b
ular
g
lan
d
s
.
1
3
Antibacterial Properties and Participation in
Film and Calculus Formation
S
aliva contains a spectrum of immunolo
g
ic and
non-immunologic proteins wit
h
anti
b
acterial
properties. In a
dd
ition, some proteins are
necessary
f
or inhibitin
g
the spontaneous
precipitation o
f
calcium and phosphate ions in
The high concentrations o
f
calcium and phosphate
in saliva
g
uarantee ionic exc
h
an
g
es
d
irecte
d
towards the tooth sur
f
aces that be
g
in with tooth
eruption resulting in post-eruptive maturation.
R
emineralization o
f
a carious tooth be
f
ore
cavitation occurs is possi
b
le, mainl
y
d
ue to t
h
e
a
vailabilit
y
o
f
calcium and phosphate ions in
s
a
li
va
.
8,
1
3,
1
8
The concentration o
f
salivar
y
calcium varies
w
ith the
S
F
8,
11
and is not a
ff
ected b
y
diet.
H
owever, diseases such as c
y
stic
f
ibrosis and
s
ome me
d
ications suc
h
as pilocarpine cause
a
n increase in calcium levels. Depen
d
in
g
on t
h
e
pH, salivar
y
calcium can
b
e ionize
d
or linke
d
.
Ionized calcium is important
f
or establishing
equili
b
rium
b
etween t
h
e calcium p
h
osp
h
ates
o
f
enamel and its ad
j
acent liquid. Non-ionized
calcium can be linked to inorganic ions (inorganic
phosphate, bicarbonate, fluoride), to small or
g
anic
ions
(
citrate
)
, and to macromolecules
(
statherin,
histidine-rich peptides, and proline-rich proteins).
A
special case o
f
the combination o
f
calcium is
its stron
g
link wit
h
α
-amilase
,
w
h
ere it acts as a
co-
f
actor necessar
y
f
or the enz
y
me
f
unction
.
8
,1
1
Inor
g
anic orthophosphate
f
ound in saliva consists
of phosphoric acid (
H
3
P
O
4
) and primar
y
(
H
2
P
O
4
-
),
s
econdar
y
(HPO
4
2-
), and tertiar
y
(PO
4
3-
) inor
g
anic
phosphate ions. The concentrations o
f
these ions
d
epen
d
on salivar
y
pH an
d
var
y
in accor
d
ance
w
ith the
S
F. As the flow increases
,
the total
concentration o
f
inor
g
anic phosphate diminishes
.
8,
11
The most important biological
f
unction o
f
this ion is
to maintain the dental structure. Another
f
unction
,
discussed previousl
y
, is its bu
ff
er capacit
y
, relevant
onl
y
in unstimulated
S
F
.
8
,1
1
The presence o
f
f
luoride in saliva, even at
physiologically low levels, is decisive
f
or the
s
tabilit
y
o
f
dental minerals. Its concentration in
total saliva is relate
d
to its consumption. It is
dependent on the
f
luoride in the environment,
especially in drinkin
g
water. Other sources are
a
lso important, such as denti
f
rices and other
pro
d
ucts use
d
in caries prevention. T
h
e presence
o
f
f
luoride ions in the liquid phase reduces mineral
l
oss durin
g
a drop in bio
f
ilm pH, as these ions
diminish the solubilit
y
o
f
dental h
y
drox
y
apatite,
makin
g
it more resistant to
d
emineralization. It
has also been demonstrated
f
luoride reduces the
production o
f
acids in bio
f
ilm
.
4
,8,11,28
5
The Journal of
C
ontemporar
y
Dental Practice, Volume 9, No. 3, March 1, 2008
s
tructure lu
b
rication, an
d
it is pro
b
a
b
le
b
ot
h
a
re important in the
f
ormation o
f
acquired
f
ilm.
A
nother
f
unction proposed
f
or the proline-rich
proteins is t
h
e capacit
y
to selectivel
y
me
d
iate
bacterial adhesion to tooth sur
f
aces
.
3
,
4
,
8
,22
T
h
e c
y
statins are also relate
d
to acquire
d
f
ilm
f
ormation and to h
y
drox
y
apatite cr
y
stal
equili
b
rium. Due to its proteinase in
h
i
b
itin
g
properties, it is surmise
d
t
h
ey act in controlling
proteo
ly
t
i
c act
i
v
i
t
y.
3,
4
,
8
,22,
3
1
The histatins, a
f
amil
y
o
f
histidine-rich
pepti
d
es
,
22
h
ave antimicro
b
ial activity a
g
ainst
s
ome strains o
f
Streptococcus mutans
32
s
s
an
d
inhibit hemoagglutination o
f
the periopathogen
P
orp
h
yromonas g
i
ng
i
va
lli
s
.
33
T
h
e
y
neutralize t
h
e
l
ipopol
y
saccharides o
f
the external membranes o
f
Gram-negative bacteria
34
an
d
are potent in
h
i
b
itors
of
Candida albicans
growth and development.
s
35
The bactericidal and
f
un
g
icidal e
ff
ects occur
through the union o
f
positively loaded histatins
w
it
h
t
h
e
b
iolo
g
ical mem
b
ranes resultin
g
in t
h
e
destruction o
f
their architecture and alterin
g
their permeabilit
y
. Other functions attributed to
these peptides are: participation in acquired
f
ilm
f
ormation and inhibition o
f
histamine release
b
y t
h
e mastocytes, suggesting a role in oral
in
f
lammati
o
n
.
21
S
alivary agglutinin, a highly glycosylated protein
f
requentl
y
associated with other salivar
y
proteins
a
nd with secretory I
g
A, is one o
f
the main
s
alivar
y
components responsible
f
or bacteria
aggl
ut
i
nat
i
on
.
22
Factors Influencing Salivary Flow and
Composition
S
everal factors ma
y
influence
S
F and its
composition. As a result, t
h
ese vary greatly
a
mon
g
in
d
ivi
d
uals an
d
in t
h
e same in
d
ivi
d
ual
u
nder di
ff
erent circumstances
.
3,
5
,
9
,
10
,
36
Individual Hydration
The de
g
ree o
f
individual
hyd
ration is t
h
e most
important
f
actor that
inter
f
eres in salivar
y
s
ecretion
.
10
W
h
en t
h
e
b
o
dy
w
ater content is re
d
uce
d
by
8
%,
S
F virtuall
y
diminishes to
zero, w
h
ereas
hy
per
hyd
ration
causes an increase in
S
F
.
9
Durin
g
d
e
h
y
d
ration,
t
h
e salivary glan
d
s an
d
in t
h
eir secretions. Bot
h
the acquired
f
ilm and the bio
f
ilm have proteins
derived
f
rom saliva
.
3
,
1
1
S
ecretory immuno
g
lobulin A (I
g
A) is the lar
g
est
immunolo
g
ic component o
f
saliva. It can
neutralize viruses,
b
acterial, an
d
enz
y
me toxins.
It serves as an antibody
f
or bacterial anti
g
ens
a
n
d
is a
b
le to a
gg
re
g
ate
b
acteria, in
h
i
b
itin
g
t
h
eir a
dh
erence to oral ti
ss
ue
s.
4,11,13,21
O
ther
immunolo
g
ic components, such as I
g
G and I
g
M,
occur in less quantity and probably ori
g
inate
f
rom
gingival
f
luid
.
3
,
4
A
mon
g
t
h
e non-immunolo
g
ic salivary protein
components, there are enz
y
mes (l
y
soz
y
me,
l
actoferrin, and peroxidase), mucin
g
lycoproteins,
agg
lutinins,
h
istatins, proline-ric
h
proteins,
s
tat
h
erins, an
d
c
y
statins
.
11,21
Ly
soz
y
me can h
y
drol
y
ze the cellular wall o
f
some
b
acteria, an
d
b
ecause it is strongly cationic, it
can activate the bacterial
“
autolisines” which are
ab
le to
d
estro
y
b
acterial cell wall components.
Gram-negative bacteria are more resistant to
this enz
y
me due to the protective
f
unction o
f
their external lipopol
y
saccharide la
y
er.
O
ther
a
ntibacterial mechanisms have been proposed
f
or
t
h
is enzyme, suc
h
as a
gg
re
g
ation an
d
in
h
i
b
ition
of
bact
e
rial a
d
h
e
r
e
nc
e.
3,
4
,
8
,
21
,
2
2
L
acto
f
errin links to
f
ree iron in the saliva causin
g
bactericidal or bacteriostatic e
ff
ects on various
microorganisms requiring iron
f
or their survival
s
uc
h
as t
h
e
Streptococcus mutans
group.
s
L
acto
f
errin also provides
f
un
g
icidal, antiviral,
a
nti-in
f
lammator
y
, and immunomodulator
y
f
unctions
.
3
,
4
,
8
,22,
3
0
Peroxidase or sialoperoxidase o
ff
ers antimicrobial
a
ctivit
y
because it serves as a catal
y
st
f
or the
oxidation o
f
the salivar
y
thioc
y
anate ion b
y
h
y
d
rogen peroxi
d
e into
h
ypot
h
iocyanate, a
potent antibacterial substance. As a result o
f
its
consumption, proteins an
d
cells are protecte
d
f
rom the toxic and oxidant e
ff
ects o
f
hydrogen
peroxi
d
e
.
3
,
4
,
8
,22
T
h
e proline-ric
h
proteins an
d
stat
h
erins in
h
i
b
it t
h
e
s
pontaneous precipitation o
f
calcium phosphate
s
alts and the
g
rowth o
f
hydroxyapatite crystals
on the tooth sur
f
ace, preventing the
f
ormation
o
f
salivar
y
and dental calculus. The
y
f
avor oral
6
The Journal of
C
ontemporar
y
Dental Practice, Volume 9, No. 3, March 1, 2008
s
aliva in the
f
loor o
f
the mouth between
s
wallow
s
.
S
ome researchers observed a small increase
in
S
F in the face of visual stimuli
,
while others
ob
s
erved no e
ff
ect whatever
.
9
Regular Stimulation of Salivary Flow
A
lt
h
oug
h
t
h
ere is evi
d
ence regular stimulation
of
S
F with the use of chewin
g
g
um leads to
a
n increase in stimulated
S
F
,
further studies
a
re require
d
to explain w
h
et
h
er t
h
is stimulation
increases unstimulated
S
F
.
9
Size of Salivary Glands and Body Weight
S
timulated
S
F is directl
y
related to the size of the
s
alivary
g
land, contrary to unstimulated
S
F which
d
oes not
d
epen
d
on its size
.
9
U
nstimulated
S
F appears to be independent of
b
o
d
y weig
h
t;
10
on t
h
e ot
h
er
h
an
d
, o
b
ese
b
o
y
s
present si
g
ni
f
icantly lower salivary amylase
concentration in comparison wit
h
controls
.
44
Salivary Flow Index
The main
f
actor a
ff
ectin
g
salivary composition
i
s
the
f
low inde
x
8
,
9
w
h
ic
h
varie
s
in accor
d
ance
w
ith the t
y
pe, intensit
y
, and duration o
f
t
h
e stimulus
.
5,
12
,
1
7
As the
S
F increases
,
the
concentrations o
f
total protein, sodium, calcium,
c
h
lori
d
e, an
d
b
icar
b
onate as well as t
h
e pH
increases to various levels
,
w
h
ereas t
h
e
concentrations o
f
inorganic phosphate and
ma
g
nesium
d
iminis
h.
3,8
Mec
h
anical or c
h
emical
s
timulu
s
i
s
a
ss
ociate
d
w
ith increased salivar
y
secretion. The action o
f
chewin
g
somethin
g
tasteless itsel
f
stimulates
s
alivation
b
ut to a lesser
d
egree t
h
an t
h
e tasty
s
timulation cause
d
by
citric aci
d.
9
Aci
d
su
b
stances
a
re consi
d
ere
d
potent
g
ustatory stimuli
.
10
Contributions of Different Salivary Glands
O
ther factors that influence total salivar
y
composition are the relative contribution o
f
the di
ff
erent salivary
g
lands and the type o
f
s
ecret
i
on
.
5
,
9
The percenta
g
e o
f
contribution by the
glands during unstimulated
S
F is as follows:
•
20%
b
y t
h
e paroti
d
g
lan
d
s
•
65%-70% su
b
man
d
i
b
ular
g
lan
d
s
•
7% to 8% su
b
lingual glan
d
s
•
<10%
b
y t
h
e minor salivary
g
lan
d
s
W
hen
S
F is stimulated
,
there is an alteration in
the percenta
g
e o
f
contribution o
f
each
g
land with
t
h
e salivary glan
d
s cease secretion to conserve
w
a
te
r
.
3
7
Body Posture, Lighting, and Smoking
S
F varies in accordance with body posture, li
g
htin
g
con
d
itions, an
d
smokin
g
. Patients kept stan
d
in
g
u
p or lying down present higher and lower
S
F,
r
espectivel
y
, t
h
an seate
d
patients. T
h
ere is a
decrease of 30% to 40% in
S
F of people that are
blind
f
olded or in the dark. However
,
the
f
low is not
l
ess in
b
lin
d
people, w
h
en compare
d
wit
h
people
w
it
h
normal vision. T
h
is su
gg
ests t
h
at
b
lin
d
people
a
dapt to the lack o
f
light that enters through the
eyes. Olfactive stimulation and smokin
g
cause
a
temporar
y
increase in unstimulated
S
F
.
9
M
e
n
that smoke present signi
f
icantly higher stimulated
S
F than non-smokin
g
men
.
38
The irritatin
g
e
ff
ect
o
f
tobacco increases
g
landular excretion
,
3
9
an
d
nicotine causes severe morphologic and
f
unctional
a
lterations in t
h
e salivary
g
lan
d
s
.
4
0
The Circadian and Circannual Cycle
S
F attains its peak at the end of the afternoon
b
ut
g
oes
d
own to almost zero
d
urin
g
sleep.
S
alivar
y
composition is not constant and is related
to the Circadian c
y
cle
.
4,
41
Th
e
c
o
nc
e
ntrati
o
n
of
total proteins attains its peak at the end o
f
the
af
ternoon, while the peak production levels o
f
s
odium and chloride occur at the be
g
innin
g
o
f
the
morn
i
n
g.
9
A
ccor
d
in
g
to E
dg
ar
,
9
t
h
e circannual r
hy
t
h
m also
in
f
luences salivar
y
secretion. In the summer lower
volumes o
f
salivary
f
lows
f
rom the parotid gland,
w
hile in the winter there are peak volumes o
f
s
ecretion. However
,
t
h
ese
d
ata were o
b
taine
d
in
the state of Texas in the southern United
S
tates
a
nd the reduction in
S
F ma
y
be associated
w
ith deh
y
dration that occurs because o
f
the hot
we
at
he
r
.
Medications
Many classes o
f
drugs, particularly those that
have anticholiner
g
ic action (antidepressants,
a
nxiol
y
tics, antips
y
c
h
otics, anti
h
istaminics, an
d
a
ntih
y
pertensives), ma
y
cause reduction in
S
F
a
n
d
alter its composition
.
9,
18
,
4
2,
43
Thinking of Food and Visual Stimulation
Thinkin
g
o
f
f
ood or lookin
g
at
f
ood are weak
s
alivation stimuli in
h
umans. It ma
y
seem t
h
at
people salivate simply because o
f
thinking o
f
f
ood,
but in realit
y
the
y
become more conscious o
f
the
7
The Journal of
C
ontemporar
y
Dental Practice, Volume 9, No. 3, March 1, 2008
is
h
ig
h.
2
Alterations in t
h
e ps
y
c
h
o-emotional
s
tate ma
y
alter the biochemical composition o
f
s
aliva. Depression is accompanie
d
by
d
iminis
h
e
d
s
alivar
y
proteins
.
48
Nutritional de
f
iciencie
s
ma
y
also in
f
luence salivar
y
f
unction and
compos
i
t
i
on
.
4,
11
Fasting and Nausea
A
lthou
g
h short-term fastin
g
reduces
S
F it does
not lead to h
y
posalivation, and the
f
low is
r
estored to normal values immediatel
y
a
f
ter the
f
astin
g
period ends
.
11
S
timulated
S
F increases
wh
en prece
d
e
d
b
y gustatory stimulation in less
than one hour be
f
ore saliva collection
.
4
9
S
aliva
s
ecretion increases be
f
ore and durin
g
vomitin
g.
9
Age
D
espite numerous stu
d
ies on salivar
y
secretion
the effect of aging on
S
F remains obscure due to
con
f
lictin
g
observations in the literature leavin
g
l
ittle information available re
g
ardin
g
S
F in healthy
el
d
erl
y
persons
.
5
0
H
istolo
g
ic analyses
h
ave
d
emonstrate
d
wit
h
a
dvancing age the parenchyma o
f
the salivary
g
lan
d
s is
g
ra
d
ually replace
d
b
y a
d
ipose an
d
f
ibrovascular tissue
,
and the volume o
f
the acini
i
s
re
d
uce
d.
51,5
2
However,
f
unctional studies among
healthy individuals indicate a
g
in
g
itsel
f
does not
necessarily lea
d
to
d
iminis
h
e
d
g
lan
d
ular capacity
to pro
d
uce saliva
.
19
N
avazes
h
et al
.
5
3
found the total unstimulated
S
F
is signi
f
icantly lower in healthy patients between
the a
g
es o
f
65 and 83 years, in comparison with
patients between the a
g
es o
f
18 and 35 years.
H
owever, total stimulated
S
F was significantly
h
i
gh
er in t
h
e el
d
erly in comparison wit
h
t
h
e
yo
un
g
er pers
o
ns
.
P
e
rcival
e
t al
.
5
0
also
f
ound the total unstimulated
S
F is related to a
g
e, bein
g
si
g
nificantly reduced
in
h
ealt
h
y non-me
d
icate
d
el
d
erly persons age
d
8
0 years or ol
d
er. However, no a
g
e-relate
d
r
eductions in stimulated
S
F from the parotid
w
ere
d
etecte
d
. It is suggeste
d
t
h
e el
d
erly
do not present d
y
s
f
unctions in the abilit
y
to
r
espon
d
to sialo
g
o
g
ues,
h
owever, t
h
e re
d
uction
in unstimulated
S
F could contribute to the
a
ppearance o
f
diseases in the oral mucosa
.
L
ima
e
t al
.
54
d
emonstrate
d
el
d
erl
y
persons
presente
d
a ver
y
low
d
ail
y
saliva pro
d
uction,
the parotids contributin
g
over 50% o
f
the total
s
alivar
y
secretion
.
3,4,11,12,4
5
T
h
e salivar
y
secretions ma
y
b
e serous,
mucous, or mixed.
S
erous secretions, produced
mainl
y
by
t
h
e paroti
d
s, are ric
h
in ions an
d
enz
y
mes. Mucous secretions are ric
h
in mucins
(glycoproteins) and present little or no enzymatic
a
ctivit
y
. T
h
e
y
are pro
d
uce
d
mainl
y
by
t
h
e
s
maller
g
lan
d
s. In t
h
e mixe
d
g
lan
d
s, suc
h
as t
h
e
s
u
b
man
d
i
b
ular an
d
su
b
lingual glan
d
s, t
h
e salivary
content
d
epen
d
s on t
h
e proportion
b
etween t
h
e
s
erous an
d
mucous cells
.
2,
8
,
13
,
1
7
Physical Exercise
P
hy
sical exercise can alter secretion an
d
in
d
uces
c
h
anges in various salivary components, suc
h
a
s: immuno
g
lo
b
ulins,
h
ormones, lactate, proteins,
a
n
d
electrol
y
tes
.
4
6
,
47
In a
dd
iti
o
n t
o
t
he
de
t
e
rmin
ed
intensit
y
o
f
the exercise, there is a clear rise
in salivar
y
levels o
f
α
-amilase an
d
electrol
y
tes
(especiall
y
Na
+
).
46
Durin
g
p
h
ysical activities
s
ympat
h
etic stimulation appears to
b
e strong
enou
gh
to
d
iminis
h
or in
h
i
b
it salivary secretion
.
47
Alcohol
The intake o
f
a sin
g
le hi
g
h dose o
f
ethanol
causes a si
g
ni
f
icant reduction o
f
stimulated
S
F. This diminishment results from the altered
r
elease o
f
total proteins and am
y
lase as well
a
s in diminished release o
f
electrol
y
tes
.
29
Rats
exposed to ethanol
f
or a prolonged period showed
s
i
g
ni
f
icant reduction in salivary secretion and
diminished release o
f
proteins
.
40
Systemic Diseases and Nutrition
In some c
h
ronic
d
iseases suc
h
as: pancreatitis,
diabetes mellitus, renal insu
ff
icienc
y
, anorexia,
b
ulimia, an
d
celiac
d
isease, t
h
e am
y
lase level
8
The Journal of
C
ontemporar
y
Dental Practice, Volume 9, No. 3, March 1, 2008
paroti
d
w
h
en compare
d
wit
h
men. W
h
ereas,
S
hern et al
.
57
reported the total unstimulated
S
F
w
as not in
f
luenced by
g
ender
.
Conclusion
S
ince several factors can influence salivar
y
s
ecretion an
d
composition a precise stan
d
ar
d
f
or saliva collection must be established.
S
uch
a
stan
d
ar
d
woul
d
make t
h
e test results o
b
taine
d
t
h
roug
h
sialometry an
d
/or sialoc
h
emistry more
help
f
ul in characterizin
g
the true
f
unctional state
o
f
the salivary
g
lands which in turn would serve
a
s indicators
f
or a diagnosis when oral and/or
sy
stemic alterations are suspecte
d.
Clinical Significance
S
ince man
y
oral and s
y
stemic conditions
mani
f
est themselves as chan
g
es in the
f
low and
composition o
f
saliva the dental practitioner is
ad
vise
d
to remain up-to-
d
ate wit
h
t
h
e current
l
iterature on t
h
e su
bj
ect
.
a
n
d
t
h
is appears to
b
e more relate
d
to s
y
stemic
diseases and the continuous use o
f
medications
t
h
an to a
g
in
g.
Gender
The di
ff
erences in salivar
y
secretion between
m
e
n an
d
w
o
m
e
n
h
av
e
bee
n attri
b
ut
ed
t
o
tw
o
t
h
eories: women present smaller salivar
y
g
lands in comparison with men and the
f
emale
h
ormonal pattern ma
y
contri
b
ute to
d
iminis
h
e
d
s
a
li
var
y
secret
i
on
.
5
0
However, menopause an
d
h
ormone replacement t
h
erap
y
are not associate
d
w
ith salivar
y
d
y
s
f
unction o
f
the parotid
.
55
T
he
r
e
w
ere no si
g
ni
f
icant di
ff
erences with re
g
ard to
S
F between health
y
pre- and post-menopausal
w
omen an
d
b
etween post-menopausal women
u
n
de
r
ho
rm
o
nal tr
e
atm
e
nt an
d
w
o
m
e
n t
h
at
d
i
d
n
o
t r
e
c
ei
v
e
tr
e
atm
e
nt
.
5
6
P
e
rcival
e
t al
.
5
0
f
ound health
y
, non-medicated
w
omen presented a lower mean
f
or total
u
nstimulated
S
F and for stimulated
S
F of the
References
1
. Berkovitz BKB, Holland GR, Moxham BJ. Oral anatomy, histology and embryology. 3rd ed. New
York: Mos
by
; 2002
.
2. Ferraris ME
G
, Munõz A
C
. Histolo
g
ia e embriolo
g
ia bucodental. 2. ed. Rio de Janeiro:
G
uanabara
K
oogan; 2006
.
3
. Ed
g
ar WM.
S
aliva: its secretion, composition and functions. Br Dent J. 1992;172:305-312
.
4. Humphre
y
S
P, Williamson RT. A review of saliva: normal composition, flow, and function. J Prosthet
D
ent. 2001
;
85:162-169
.
5
. Jenkins GN. The physiolo
g
ic and biochemistry of the mouth. 4th. ed. Oxford: Blackwell Scientific
Pu
b
lications
;
1978
.
6
. Washington N, Washington C, Wilson CG. Physiological pharmaceutics: barriers to drug absorption.
London: CRC Press
;
2000
.
7
. Tabak LA. A revolution in biomedical assessment: the development o
f
salivary dia
g
nostics. J Dent
E
d
uc. 2001
;
65:1335-1339
.
8
. Tenovuo J, La
g
erlöf F. Saliva. In: Thylstrup A, Fejerskov O. Textbook of clinical cariolo
g
y. 2nd ed.
C
openha
g
en: Munks
g
aard; 1994
.
9
. Edgar M, Dawes C, O’Mullane D. Saliva and oral health. 3rd ed. London: BDJ Books; 2004
.
1
0. Dawes C. Physiolo
g
ical factors affectin
g
salivary flow rate, oral su
g
ar clearance, and the sensation
o
f
dr
y
mouth in man. J Dent Res. 1987;66:648-653
.
1
1. Axelsson P. Diagnosis and risk prediction of dental caries. v. 2. Illinois: Quintessence books; 2000
.
1
2. Dou
g
las CR. Tratado de fisiolo
g
ia aplicada à saúde. 5. ed. São Paulo: Robe Editorial; 2002
.
1
3. Ten
C
ate AR.
O
ral histolo
g
y: development, structure and function. 5th ed.
S
t. Louis: Mosby; 1998
.
1
4. Malamud D.
S
alivary diagnostics: the future is now. J Am Dent Assoc. 2006;137:284-286
.
1
5. González LFA, Sánches MCR. La saliva: revisión sobre composición, función y usos dia
g
nósticos:
primera parte. Univ
O
dontol. 2003;23:18-24
.
1
6. Turner RJ, Sugiya H. Understanding salivary fluid and protein secretion. Oral Dis. 2002;8:3-11
.
1
7. Costanzo LS. Fisiolo
g
ia. 2. ed. Rio de Janeiro: Elsevier; 2004
.
1
8.
S
tack KM, Papas A
S
. Xerostomia: etiolo
g
y and clinical mana
g
ement. Nutr
C
lin
C
are. 2001;4:15-21
.
1
9. Nagler RM.
S
alivary glands and the aging process: mechanistic aspects, health-status and
medicinal-e
ff
icacy monitorin
g
. Bio
g
erontolo
g
y. 2004;5:223-33
.
9
The Journal of
C
ontemporar
y
Dental Practice, Volume 9, No. 3, March 1, 2008
2
0. Tabak LA, Levine MJ, Mandel ID, Ellison
S
A. Role of salivar
y
mucins in the protection of the oral
cavit
y
. J Oral Pathol. 1982;11:1-17
.
2
1.
S
chenkels L
C
, Veerman E
C
, Nieuw Ameron
g
en AV. Biochemical composition of human saliva in
r
elation to other mucosal fluids. Crit Rev Oral Biol Med. 1995
;
6:161-175
.
2
2. Ameron
g
en AV, Veerman EC. Saliva: the defender of the oral cavity. Oral Dis. 2002;8:12-22
.
2
3. Ben-Aryeh H,
C
ohen M, Kanter Y,
S
zar
g
el R, Laufer D.
S
alivary composition in diabetic patients.
J Diabet Complications. 1988;2:96-99
.
2
4. Jaffe EC, Roberts GJ, Chantler C, Carter JE. Dental findin
g
s in chronic renal failure. Br Dent J.
1
98
6;
1
6
0:18-20
.
2
5. Ertugrul F, Elbek-Cubukcu C, Sabah E, Mir S. The oral health status of children undergoing
h
emo
d
ial
y
sis treatment. Turk J Pe
d
iatr. 2003;45:108-113
.
2
6. Lucas V
S,
Roberts
G
J.
O
ro-dental health in children with chronic renal failure and after renal
transplantation: a clinical review. Pe
d
iatr Nep
h
rol. 2005;20:1388-1394
.
2
7. Macpherson LMD, Dawes C. Urea concentration in minor mucous
g
land secretions and the effect of
s
alivar
y
film velocit
y
on urea metabolism b
y
S
treptococcus vestibularis in an artificial plaque.
J Perio
d
ontal Res. 1991
;
26:395-401
.
2
8. Larsen MJ, Bruun C. A química da cárie dentária e o flúor: mecanismos de a
ç
ão. In: Thylstrup A,
Fejerskov
O
.
C
ariolo
g
ia clínica. 3. ed.
S
ão Paulo: Livraria Editora
S
antos; 2001
.
2
9. Enberg N, Alho H, Loimaranta V, Lenander-Lumikari M.
S
aliva flow rate, amylase activity, and protein
a
nd electrolyte concentrations in saliva after acute alcohol consumption. Oral Sur
g
Oral Med Oral
Pathol
O
ral Radiol Endod. 2001
;
92:292-298
.
3
0. Nikawa H,
S
amaranayake LP, Tenovuo J, Pang KM, Hamada T. The fungicidal effect of human
l
actoferrin on Candida albicans and Candida krusei. Arch Oral Biol. 1993
;
38:1057-1063
.
3
1. Blankenvoorde MF, Henskens YM, van’t Hof W, Veerman E
C
, Nieuw Ameron
g
en AV. Inhibition of the
growth and cysteine proteinase activity of Porphyromonas gingivalis by human salivary cystatin
S
a
nd chicken c
y
statin. Biol Chem. 1996;377:847-850
.
3
2. Macka
y
BJ, Denepiti
y
a L, Iacono VJ, Krost
S
B, Pollock JJ.
G
rowth-inhibitor
y
and bactericidal
effects of human parotid salivar
y
histidine-rich pol
y
peptides on
S
treptococcus mutans. Infect
I
mmun.1984
;
44:695-701
.
3
3. Murakami Y, Tama
g
awa H,
S
hizukuishi
S
, Tsunemitsu A, Aimoto
S
. Biolo
g
ical role of an ar
g
inine
r
esidue present in a histidine-rich peptide which inhibits hemagglutination o
f
Porphyromonas
g
in
g
ivalis. FEM
S
Microbiol Lett. 1992;77:201-204
.
3
4.
S
u
g
iyama K. Anti-lipopolysaccharide activity of histatins, peptides from human saliva. Experientia.
1
993
;4
9:1095-1097
.
3
5. Xu T, Levitz SM, Diamond RD, Oppenheim FG. Anticandidal activit
y
of major human salivar
y
histatins. In
f
ect Immun. 1991
;
59:2549-2554
.
3
6. Dawes C. Effects of diet on salivar
y
secretion and composition. J Dent Res. 1970;49:1263-1273
.
3
7. Tortora GJ. Corpo humano: fundamentos de anatomia e fisiolo
g
ia. 4. ed. Porto Ale
g
re: Artmed; 2000
.
3
8. Axelsson P, Paulan
d
er J, Lin
dh
e J. Relations
h
ip
b
etween smokin
g
an
d
d
ental status in 35, 50, 65
a
nd 75
y
ear-old individuals. J Clin Periodontol. 1998;25:297-305
.
3
9. Thomson WM, Chalmers JM, Spencer AJ, Slade GD. Medication and dry mouth: findin
g
s from a
cohort stud
y
o
f
older people. J Public Health Dent. 2000;60:12-20
.
40. Maier H, Born IA, Mall G. Effect of chronic ethanol and nicotine consumption on the function and
morpholo
g
y of the salivary
g
lands. Klin Wochenschr. 1988;66(
S
uppl 11):140-150
.
41. Dawes
C
.
C
ircadian rh
y
thms in human salivar
y
flow rate and composition. J Ph
y
siol.
1
972
;
220:529-545
.
42. Atkinson JC, Baum BJ. Salivar
y
enhancement: current status and future therapies. J Dent Educ.
2
001
;6
5:109
6
-1101
.
43. Guggenheimer J, Moore PA. Xerostomia: etiology, recognition and treatment. J Am Dent Assoc.
2
003
;
134:61-69
.
44. de
O
liveira
CG
,
C
ollares EF, Barbieri MA, Fernandes MIM. Produção e concentração de saliva e
a
milase salivar em crian
ç
as obesas. Arq Gastroenterol. 1997;34:105-111
.
10
The Journal of
C
ontemporar
y
Dental Practice, Volume 9, No. 3, March 1, 2008
45. Edgar WM. Saliva and dental health. Clinical implications of saliva: report of a consensus meeting.
Br Dent J. 1990
;
169:96-98
.
46.
C
hicharro JL, Lucia A, Perez M, Vaquero AF, Urena, R.
S
aliva composition and exercise.
S
ports
Me
d
. 1998
;
26:17-27
.
47. Li TL, Gleeson M. The effect of sin
g
le and repeated bouts of prolon
g
ed cyclin
g
and circadian
variation on saliva flow rate, immuno
g
lobulin A and alpha-amylase responses. J
S
ports
S
ci.
2
004
;
22:1015-1024
.
48. Gri
g
oriev IV, Nikolaeva LV, Artamonov ID. Protein content of human saliva in various psycho
-
emotional states. Biochemistr
y
(Mosc). 2003;68:405-406
.
49. Dawes C, Chebib FS. The influence of previous stimulation and the da
y
of the week on the
concentrations of protein and the main electrol
y
tes in human parotid saliva. Arch Oral Biol.
1
972
;
17:1289-1301
.
5
0. Percival RS, Challacombe SJ, Marsh PD. Flow rates of resting whole and stimulated parotid saliva
in relation to a
g
e an
d
g
en
d
er. J Dent Res. 1994;73:1416-1420
.
5
1. Azevedo LR, Damante JH, Lara V
S
, Lauris JR. A
g
e-related chan
g
es in human sublin
g
ual
g
lands: a
post mortem stud
y
. Arch Oral Biol. 2005;50:565-574
.
5
2. Moreira CR, Azevedo LR, Lauris JR, Ta
g
a R, Damante, JH. Quantitative a
g
e-related differences in
human sublin
g
ual
g
land. Arch
O
ral Biol. 2006;51:960-966
.
5
3. Navazesh M, Mulligan RA, Kipnis V, Denny PA, Denny PC. Comparison of whole saliva flow
r
ates and mucin concentrations in healthy Caucasian youn
g
and a
g
ed adults. J Dent Res.
1
992
;
71:1275-1278
.
5
4. Lima AAS, Machado DFM, Santos AW, Grégio AMT. Avalia
ç
ão sialométrica em indivíduos de
terceira idade. Rev Odonto Ciênc. 2004
;
19:238-244
.
5
5.
G
hezzi EM, Wa
g
ner-Lan
g
e LA,
S
chork MA, Metter EJ, Baum BJ,
S
treckfus
C
F,
S
hip JA.
L
ongitudinal in
f
luence o
f
age, menopause, hormone replacement therapy, and other medications on
parotid flow rates in health
y
women. J Gerontol A Biol Sci Med Sci. 2000;55:34-42
.
5
6.
S
hip JA, Patton LL, T
y
lenda
C
A. An assessment of salivar
y
function in health
y
premenopausal an
postmenopausal females. J Gerontol. 1991;46:11-5
.
5
7. Shern RJ, Fox PC, Li SH. Influence of a
g
e on the secretory rates of the human minor salivary
g
lands and whole saliva. Arch
O
ral Biol. 1993;38:755-761
.
About the Authors
11
The Journal of
C
ontemporar
y
Dental Practice, Volume 9, No. 3, March 1, 2008