Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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THE EFFECT OF A BUFFERING AGENT ON
ACIDOGENESIS OF PLAQUE
Field of the Invention
This invention provides a Trim water formulation that minimizes acidification
from
forming inside the mouth to treat dental caries. The Trim water may be
provided in the form of
mouthwash or drinking formulations to treat dental caries.
Related Art
Dental caries (tooth decay) is one of the most common oral diseases. Dental
caries often
appears as a white chalky area on the tooth enamel. This occurs in teeth where
microbial plaque
exists. Fermentable carbohydrates such as sugars in the diet are metabolized
to acids such as lactic
acid by plaque bacteria causing a pH change at the tooth surface. If the pH is
sufficiently acidic and
is not neutralized, the tooth, which is comprised mainly of calcium phosphate
crystals such as
hydroxyapatite will dissolve or decalcify producing a carious lesion. This
area of the tooth then
softens to later break down the structure of the tooth to form a cavity. If
the tooth is not treated in
the early stage, it can progress towards the pulp and require extensive
treatment to save the tooth.
A diet with high concentration of sugar increases the risk of tooth decay.
After a single
sugar challenge, some surface decalcification will take place, but the damage
will be reversed
(recalcification) if the acid is neutralized within a short period of time
after the sugar challenge
(within . 40 to 60 . minutes). This neutralization, or buffering, takes place
naturally . by
ammonia-producing bacteria in plaque. If sugar challenges are frequent,
especially with children
that frequently eat sweet snacks during the day, neutralization of plaque pH
and recalcification will
not take place. Cavitation of the tooth will result if the latter process
continues for a few months.
Frequent sugar challenges also cause the microbial composition of plaque to
shift toward one which
is more acidogenic and aciduric. A pH at or below 5.5 is generally accepted as
. critical for
decalcification.
Limiting the dietary intake of sugar can reduce the chance of dental caries
from
occurring. This is, however, very difficult for most children who crave sugar.
Another approach
would be enhancement of plaque neutralization after sugar challenges. This has
been attempted
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experimentally by having subjects chew sugar-free chewing a gum after sweet
snacks, which
theoretically stimulates saliva flow and thereby increases salivary
bicarbonate concentrations, the
main buffer in saliva. The increased saliva flow and the chewing action also
helps clear the oral
sugar concentrations. Reduction of dental caries has been reported using this
technique (Scheinin,
Acta Odont Scan 33:267, 1975). However, chewing a gum after a sugar intake may
not be
appropriate at times and the gum may.need to be chewed for some time to
increase the saliva flow,
U.S. Patent No. 5,938,915 (Morisawa) discloses electrolyzed water having an
oxidization-reduction potential in the range of about -150 to about 0 mV
measured against a
platinum electrode. Water as described in U.S. 5,938,915 is known as "Trim
water", which term is
used herein interchangeably with the term "Trim". Trim water may be produced
in either acidic or
alkaline form.
One way the Trim water may be made comprises the steps of providing an
electrolytic
water treatment apparatus including a cathode chamber with a cathode and an
anode chamber. with
an anode, wherein the chambers are separated by a diaphragm, and further
introducing raw water
into the cathode chamber and the anode chamber, applying a~ current within a
range of about 0.16
mA/cm2 to about 3.2 mA/cm2 per each pair of electrodes and a diaphragm across
the cathode and
anode for about 0.5 seconds to about 5 seconds for electrolyzing the raw
water, and then extracting
the electrolyzed water from the cathode chamber, thereby obtaining the Trim
water.
In certain instances, the current range may be within a range of about 0.224
mA/cm2 to
about 1.6 m.A/cm2. In another embodiment, the- extracted electrolyzed water
may be boiled or further
filtered. By Trim water, boiled and filtered water are included so long as the
water has passed
through the current as discussed above.
In another embodiment, the extracted electrolyzed water may be boiled or
further filtered.
By Trim water, boiled and filtered water are included so long as the water has
passed through the
current as discussed above. In this way, the Trim water was found to be rich
in electrons.
SUMMARY OF THE INVENTION
This invention provides a Trim water formulation to prevent or treat dental
caries by
preventing the acidification solution from forming inside the mouth. Trim
water (alkaline) is used as
a post-sugar snack rinse that neutralizes plaque acids and enhance
recalcification of teeth. As such,
rinsing with Trim water substantially prevents dental caries from occurring in
teeth. .Trim water may
be provided in a variety of formulations such as mouthwash rinse and drinkable
beverage.
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The Trim water may be placed into a cariostatic formulation to be administered
near the
tooth. The Trim water may be acidic or alkaline. The time of administration
may be for about one
minute near the location of the teeth. For example, a mouthwash rinse may .be
rinsed for about 1
minute. Preferably, the mouth rinse or beverage of the invention results in
the maintenance of pH
above 5.5 near the tooth.
These and other objects of the invention will be more fully understood from
the following
description of the invention, the referenced drawings attached hereto and the
claims . appended
hereto:
BRIEF DESCRIPTION OF THE DRAWINGS '
The present invention will become more fully understood from the detailed
description
given below, and the accompanying drawings which are given by way of
illustration only, and thus
are not limitative of the present invention, and wherein;
Figure 1 shows the pH response of Streptococcus mutans in plain water or Trim
water
containing 5% sucrose.
Figure 2 shows the pH response of tooth #26 after a one-minute rinse with
water.
Figure 3 shows the pH response of tooth #26 after a one-minute rinse with Trim
water.
Figure 4 shows the ~pH response of tooth #27 after a one-minute rinse with
water.
Figure 5 shows the pH response of tooth #27 after a one-minute rinse with Trim
water.
Figure 6 shows the pH response of tooth #28 after a one-minute rinse with
water.
Figure 7 shows the pH response of tooth #28_ after a one-minute rinse with
Trirri water.
Figure 8 shows the pH response of tooth #29 after a one-minute rinse with
water.
Figure 9 shows the pH response of tooth #29 after a one-minute rinse with Trim
water.
Figure 10 shows the pH response of tooth #26 in Trim water containing 5%
sucrose.
Figure 11 shows the pH response of tooth #27 in Trim water containing 5%
sucrose.
Figure 12 shows the pH response of tooth #28 in Trim water containing 5%
sucrose,
Figure 13 shows the pH response of tooth #29 in Trim water containing 5%
sucrose.
Figures 14A to 14L shows sequential radiography of teeth exposed to
Streptococcus
mutans and Lactobacillus casei.
DETAILED DESCRIPTION OF THE PREFERRED EMBODTMENTS
Experiments to evaluate the buffering potential of Trim water and three
experiments
using in vitro cariogenic plaque are described below. Experiments were
designed to test
anti-cariogenic potential of Trim as a 1 ) post sugar rinse; 2) base for a
sweet beverage, and 3)
cariostatic agent for active carious lesions.
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Since in vivo rinsing exposes Trim water to human saliva that contains a
bicarbonate
buffering system, the pH of Trim water was measured after mouth rinsing for
different periods of
time (Table 1). A 3-minute rinse with either acidic or alkaline Trim water
showed salivary buffering
to change the pH from 11.2 (alkaline) or 2.94 (acidic) to between 6 and 7.
With shorter rinse of up
to one minute, alkaline Trim remained above pH 9 even when sucrose was
present.
Using caries ~ model experiments, the following advantages of the inventive
method are
seen.
1. A 1-minute rinse with alkaline Trim water produced a rapid buffering of
sucrose-
exposed experimental cariogenic dental plaques. The pH remained above 5.5,
which is the generally
accepted pH when the enamel starts to decalcify, for at least 25 minutes.
Normally, most sugar-
containing snacks or beverages become cleared from the mouth within 25
minutes. Water rinsing
did not provide an adequate anti-acid effect. (Figures 2-9)
2. Compared with water containing sucrose, Trim plus sucrose kept the pH above
5.5 for
at least~25 minutes. When Trim plus sucrose was cleared from the plaques by a
1-minute water
rinse, the pH continued to remain above 5.5 for an additional 25 minutes.
Water plus sucrose failed
to maintain the plaque pH within the protective range.
3. Trim rinsing did not greatly alter the pH within active experimental
carious lesions
which remained fairly constant at approximately pH 4.
Thus, frequent oral exposure to Trim in the form of a beverage or a mouth
rinse may have
caries-preventative effects, particularly if employed immediately after a
sugar challenge.
Therefore, use of Trim as a base for a sweet beverage appears preferable to
water as a
base. However, since there may be some residual cariogenic effects of sugar
after Trim is cleared
from the mouth, or buffered by saliva, its use in sugar-free beverages is
recommended. This should
provide a non-cariogenic, and may also produce an anti-caries effect since an
alkaline pH enhances
recalcification of teeth.
In addition, use of Trim to arrest active carious lesions or prevent
acidogenesis within the
lesions does not seem feasible.
The following examples are offered by way of illustration of the present
invention, and
not by way of limitation.
EXAMPLES
Example 1. Effect of Trim Water on Streptococcus mutans Exposed to Sucrose
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The purpose of this experiment is to determine if Trim can reduce
acidogenicity of S.
mutans.
As a control, washed cells of Streptococcus mutans (GEM], the primary pathogen
in
human dental caries, was incubated in water containing 5% sucrose for 35
minutes. The pH changes
were monitored with a pH meter. The same number of cells was also incubated in
Trim water
containing 5% sucrose for 3.5 minutes and the pH monitored.
Water containing S% sucrose showed a decrease in pH from 5.02 to 4.06 during
35
minutes exposed to S. mutans. With Trim water containing 5% sucrose the pH
decreased from 10.4
to 9.15. The latter pH range was well within the safe range for tooth
integrity. (Decalcification
usually takes place below pH 5.5)
Example 2. In vivo Mouth Rinse with Trim or Trim Plus Sucrose
The purpose of this experiment is 1) to test the effect of oral exposure on
the pH of Trim
with and without sucrose and 2) to determine if Trim will buffer acidogensis
of salivary bacteria for
a prolonged period of time.
Trim containing 10% sucrose was rinsed in vivo for 3 minutes and then
expectorated into
a container, which was incubated at 37°C for 110 minutes. The pH was
monitored with a pH meter.
A control solution with water containing 10% sucrose was examined similarly.
Trim was rinsed in vivo for 5, 10, 15 and 30 seconds. After each rinse it was
expectorated into a container and the pH was measured. The same experiment was
repeated with
water.
Trim containing 10% sucrose was rinsed in vivo for 5, 15, 30 and 60 seconds.
After each
rinse it was expectorated into a container and the pH was measured. The same
experiment was
repeated with water.
A 3-minute rinse with Trim containing 10% sucrose in vivo caused a pH drop
from 10.33
(original pH of Trim plus sucrose) to 6.25. After incubation of the
expectorated rinse containing
saliva for 110 minutes at 37°C, the pH decreased to 5.59.
The same experiment with water plus 10% sucrose resulted in a pH change from
5.61 to
6.45 after a 3-minute rinse in vivo. During the 110-minute incubation of the
expectorated rinse, the
pH dropped from 6.45 to 5.95.
The same experiment repeated with acidic Trim changed from a pH of 2.94 to
5.45 after a
3 minute rinse and to 5.53 after a 110 minute incubation of the expectorated
mouthrinse.
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These data show strong buffering potential of saliva when Trim is kept in the
mouth for 3
minutes. When shorter rinses (up to 1 minute) with Trim were employed, the pH
remained high.
(Table 1)
Table 1. In Vivo Rinses with 20m1 of Trim or Water Solutions
Rinse Trim+10% Water+10% Acidic Trim pH Water pH
time
sucrose sucrose Trim+10%
pH pH
sucrose
pH
Original 10,33 7.38 2.94 11.20 6.96
sec 9.54 6.62 10.34 6.87
l Osec - 10.24. 6.78
sec (6.98) 6.36 9.81 6.70
30 sec 9.04 6.19 9.27 6.63 ~ -
60 sec 7.33 6.06
3 min 6.51 6.25 - 5.45
Post
Rinse
5 min 6.45 6.21 5.45
10 min 6.53 6.30 5.46
l5min 6.49 6.27 5.48
20min 6.55 6.31 5.49
20min 6.55 6.31 5.49
35min 6.48 6.25 5.51
SOmin 6.36 6.19 5.52
110min 5.95 5.59 5.53
Example 3. In Vitro Dental Caries Model
According to a Dentinal Caries Model System (Minah, Pediat. Dent 20:345,1998),
crowns of extracted in tact primary teeth were mounted in acrylic bases shaped
to fit a_ holding jig in
a digital radiograph apparatus, which permitted accurate positioning for
sequential exposures. After
enamel was covered with a layer of cold-cure acrylic, the dentin was exposed
by circular openings
1.0 mm in diameter made with a # 330 rotating dental bur. Dental caries-like.
lesions were induced
by exposure for 6 weeks to Streptococcus mutans GEM, a biotype I clinical
isolate (S m.), and
Lactobacillus casei (ATCC 11578) (L. c.) according fo the following protocol:
mounted teeth were
placed in Brain Heart Infusion broth (BHI; Difco, Detroit, MI) containing 5.0%
sucrose w/v which
was inoculated with S. m. The medium was changed daily and incubation
conducted at 37°C for 7
days in air containing 10% COZ. At day 8, mounted teeth were placed in MRS
broth (Difco)
containing 5.0% sucrose which was inoculated with L. c. This medium was
alternated daily with a
solution of 0.85% NaCI (normal saline) and 5.0% w/v sucrose. Incubation
proceeded for an
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additional 97 days. Incremental caries progression was evaluated by sequential
radiography. Spot
microbial culturing of lesions was conducted.
Teeth were incubated with pure cultures of cariogenic bacteria for 105 days.
Dentinal-
like carious lesions appeared in the teeth and progressed with time (Figures
14A to 14L).
Example 4. Effect of a 1-Minute Rinse with Trim or Water on Acidogenesis of
Experimental Dental Plaque (Indirect Plaque pH lvIeasurements) See Figures 2-
9.
The purpose of this experiment .is to simulate the effect. on acidogenesis of
plaque
following a 1-minute Trim rinse.
Mounted teeth containing cariogenic plaques were removed from the incubation
medium
and rinsed in 0.85% saline solution (normal saline) to remove substrates and
allow glycolysis to
cease. Mounted teeth were then placed in 2 ml of water with 5% sucrose for 25
minutes at 37°C.
This procedure simulated a typical dietary exposure to a cariogenic substrate.
During this time pH
of the water was measured by a pH meter (OrionTM 420A, Fisher Scientific) with
a Ross combination
microelectrode (Orion, Fisher). Teeth were then immersed for 1 min in either
Trim (test solution) or
water (control solution) after which they were placed in 2 ml of water and the
pH was monitored for
additional 25 minutes.
Teeth exposed to 5% sucrose in water for 25 minutes decreased the plaque pH
from
approximately 6.5 to 4.00. After a 1 minute water rinse the pH returned to
about 5.00 and dropped to
4.00 after an additional 25 minutes of incubation.
After a 1 minute Trim rinse, the pH rose to roughly 7.5 and then dropped to
about 5.5
after an additional 25 minute incubation.
Trim appeared to have a protective effect on cariogenic plaque after a 1
minute rinse
since acidity was immediately raised to a safe level and it remained above the
critical pH of 5.5 for
up to 25 minutes.
Example S. Effect of Trim or Water containing 5% sucrose on Acidogenesis of
Experimental Cariogenic Plaque (Indirect Plaque pH Measurements). See Figures
10-13.
The purpose of this experiment is to test plaque acidogenesis during exposure
to Trim
containing a cariogenic substrate.
The steps outlined in Example 2 above was repeated with the exception that
Trim
containing 5% sucrose replaced 5% sucrose in water during the first
incubation. All teeth were then
rinsed in water for 1 minute and. the pH was followed for additional 25
minutes.
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When Trim containing 5% sucrose was incubated with cariogenic plaques for 25
minutes
the pH decreased from about 10.0 to 6.2. After a 1 minute water rinse the pH
continued to drop to
approximately 5.0 when incubated in water for additional 25 minutes.
These results indicate that if Trim were the base for a sweet drink, for
example, pH of
plaque would not decrease to a cariogenic level when the Trim drink is present
in the mouth. Plaque
acidogenesis would continue, however, after it is cleared by washing with
water or perhaps,.
swallowing.
Example 6. Effect of a l-minute rinse with Trim or Water on Acidogenesis of
Experimental Dental Plaque (Direct Plaque pH Measurements)
The purpose of this experiment is to simulate the effect on acidogenesis of
plaque
following a 1-minute Trim rinse.
The steps outlined in Example 2 above was followed with the exception that
plaque pH
was measured directly with a microelectrode (Wpi Inc. MEPH-3TM touch
microelectrode,
Londonderry, NH).
In this experiment, pH was measured directly within experimental lesions.
During a
25-minute incubation with 5% sucrose, the pH decreased only slightly from
approximately 4.2 to
4Ø After a 1 minute rinse with Trim the pH rose to roughly 7.00 in 3 of 4
teeth and decreased to
about 4.5 during a second 25 minute incubation. When the plaques were rinsed
with the control
solution, water, and then incubated far additional 25 minutes, the pH remained
at approximately
4.00. This experiment seemed to indicate that Trim buffering capacity would
not be very effective
in deep carious lesion. Results are tabulated below (Table 2).
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Table 2. Effect of a 1-Minute Trim or Water Rinse on Acidogenesis of
Artificial Carious Lesions
Incubations#26 #27 #28 #29 Incubations#26 #27 #28 #29
~
Original 3.91 3.85 4.04 4.10 Original 3.91 3.57 3.75 3.42 ,
pH pH
CONTROL _ TEST
Water+5% Water+5%
sucrose sucrose
~
0 min 4.04 3.97 4.05 4.32 0 min 4.10 4.41 4.29 4.20
12 min 4.02 4.03 4.10 4.12 12 min 4.03 4.05 4.20 4.28
25 min 4.03 4.03 4.14 4.10 25 min ~ 3.93 4.10 4.17 3.97
1 min WATER 1 min TRIM
Rinse Rinse
Water Water
0 min 3.92 3.88 4.23 4.13 0 min 6.75 4.72 7.25 7.19
12 min 3.94 3.98 4.19 4.15 12~ min 4.83 4.58 4.53 5.27
25 min 4.06 3.99 4.11 4.03 25 min 4.65 4.26 4.34 4.72
Those skilled in the art will recognize, or be able to ascertain using no more
than routine
experimentation, many equivalents to the specific embodiments of the invention
specifically
described herein. Such equivalents are intended to be encompassed in the scope
of the following
claims.
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