Download EFFICACY OF FLUORIDE VARNISHES IN THE PROPHYLAXIS OF

49
Research report
Fluoride 39(1)49–52
January-March 2006
Fluoride varnishes for protection against dental erosion
Waszkiel, Marczuk-Kolada, Grądzka-Dahlke
49
EFFICACY OF FLUORIDE VARNISHES IN THE PROPHYLAXIS OF
DENTAL EROSION
Danuta Waszkiel,a Grażyna Marczuk-Kolada,a Małgorzata Grądzka-Dahlkeb
Białystok, Poland
SUMMARY: To evaluate the prophylactic effect of fluoride varnishes on acid erosion
of dental enamel, 40 teeth with paracervical erosion lesions located on labial and
buccal surfaces were studied in five male and five female patients aged 18–30 years.
Teeth on opposite sides of the mouth were coated three or six times at two-week
intervals with either Duraphat® or Fluoride-Protector® varnishes. After a year,
enamel loss from acid corrosion was measured in the varnished teeth and found to
be less with six than with three applications and only slightly different for the two
varnishes.
Keywords: Acid erosion; Dental enamel; Duraphat®; Enamel erosion; Fluoride-Protector®;
Fluoride varnishes.
INTRODUCTION
Dental erosion is caused by the action of acids on enamel hard tissue. Depending
on the extent of acid present in the oral cavity, the causes can be intrinsic or
extrinsic. Intrinsic factors are involved when enamel damage occurs by contact of
teeth with gastric acid due to chronic vomiting or gastric reflux.1-4 Extrinsic
causes arise from the environment, diet, medications, and lifestyle, with dietary
factors being the most significant.5-9
Because an increased incidence of enamel erosion has been noted in a number of
scientific studies, prophylactic management schemes have been proposed to
determine and eliminate risk factors as well as to improve resistance of dental hard
tissues to the action of demineralizing agents.10-12
The topical protective effect of fluoride against dental caries is widely accepted
and promoted for the prevention of tooth decay. Many authors associate the
reduced incidence of caries observed in the European countries with topical
application of fluoride preparations. However, the efficacy of fluorides for
protection against dental erosion is presumptive and equivocal. Experiments
carried out on animal models,13 have demonstrated a protective effect of topical
fluoride compounds on dental hard tissues against acid-induced demineralization,
which, however, has not been confirmed in humans.14
The aim of this study was to evaluate the progress of hard tissue erosion in teeth
coated with two different fluoride-containing enamel varnishes.
MATERIAL AND METHODS
Our study involved 40 teeth with paracervical erosions of dietary origin located
on labial and buccal surfaces in 10 dental patients, five women and five men, aged
18-30 years. All patients received oral information about the study and signed
their consent to participate in the trial. The study was approved by the Ethics
Committee, Medical University of Bia³ystok. All examined individuals completed
aDepartment
of Pedodontics, Medical University of Białystok, Poland, bFaculty of Mechanical
Engineering, Białystok Technical University, Poland. For correspondence: Dr Danuta Waszkiel,
Department of Pedodontics, Medical University of Białystok, 15-274 Białystok, ul. Waszyngtona
15A, Poland. E-mail [email protected]
50
Research report
Fluoride 39(1)49–52
January-March 2006
Fluoride varnishes for protection against dental erosion
Waszkiel, Marczuk-Kolada, Grądzka-Dahlke
50
a questionnaire concerning nutritional preferences, oral hygiene, and tooth
brushing habits. Atypical erosions were found both in the maxilla and in the
mandible, more frequently on the left (53.6%) than on the right side (46.4%).
Patients with enamel erosions consumed citrus fruits, apples, fruit juices, and
carbonated drinks. All patients were instructed to eliminate causal factors and to
institute anti-destructive procedures. Assessment of dietary habits showed a
preference of sour food products in most patients. Most of the patients brushed
their teeth three or more times a day using a variety of toothpastes. Five patients
cleaned their teeth with circular movements, two brushed with horizontal
movements, while three used the toothbrush freely. They all exhibited good oral
hygiene.
In the next stage of the experiment, the teeth were isolated from the saliva,
mechanically brushed, and impressions were taken using an impression material
Express (3M, USA). Next, the teeth were covered with varnishes containing
fluoride compounds. Duraphat® varnish was applied to lesions on one side of the
dental arch, while Fluoride Protector® was applied on the other side. In each
patient, two teeth were varnished three times and the next two six times at twoweek intervals. A year after the start of the experiment, the teeth were imprinted
again. Blue Express 7301 H models were constructed from these impressions.
Erosion progress was measured after one year using our own modification of
techniques described by Xhonga et al.14 and Bishop et al.15, which allowed
repeatability of results. The silicone imprint constructed a year earlier was
superimposed on the same tooth model. MaxSil (Rhodia Chem Italy S.p.A) of a
contrastive hue was used to fill up the space between the imprint and the model.
Dental models were cut in the median line along their long axis. Specimens were
then prepared by sawing a 1 mm thick slice from each half and checked under a
Universal Measurement Microscope (Carl Zeiss Jena) equipped with a calibrated
ocular grid. The inspection of dental cross-sections allowed detection and
measurement of sites with the thickest layer of the impression material.
The results were subjected to statistical analysis using the Mann-Whitney test
and a statistical pack SPPP. They were considered statistically significant at
p<0.05.
RESULTS
Enamel loss after three and six varnish applications are given in Table 1. It was
found that erosion progression depends on the number of fluoridation procedures.
Differences in erosion progression between the three-fold and six-fold varnishing
were statistically significant both for Fluoride Protector® (p<0.005) and
Duraphat® (p<0.001).
Table 1. Enamel loss after three- and six-fold applications of varnishes: Fluoride Protector® and Duraphat®
No. of
Type of varnish
No. of
Erosion progression
SD
Daily erosion
applications
teeth
after a year (µm)
progression (µm)
Fluoride Protector®
10
236.6*
63.94
0.65
3
Duraphat®
10
268.9†
82.17
0.74
6
Fluoride Protector®
Duraphat®
10
10
127.2
119.3
Compared with three and six applications of varnishes: *p<0.005; †p<0.007.
62.60
65.49
0.34
0.32
51
Research report
Fluoride 39(1)49–52
January-March 2006
Fluoride varnishes for protection against dental erosion
Waszkiel, Marczuk-Kolada, Grądzka-Dahlke
51
Table 2 shows erosion progression. It is affected by lesion location. Erosion was
significantly more advanced in the upper teeth following three-fold varnishing
compared with the lower teeth (p<0.001). The six-fold varnishing provided better
protection of enamel surface against the action of acids, although in this case
more substantial progression was also observed in the maxilla than in the
mandible, the differences being statistically significant (p<0.002).
Table 2. Enamel loss with regard to the location of erosion-like lesions and the
number of varnish applications
No. of
Location
No. of
Erosion progression
SD
applications
teeth
after a year (µm)
Upper teeth
10
297.3*
58.18
3
Lower teeth
10
208.2†
60.27
6
Upper teeth
Lower teeth
12
8
150.9
100.1
67.38
23.68
Compared with three and six applications of varnishes: *p<0.005; †p<0.007.
DISCUSSION
Acid resistance of enamel is determined by its composition and chemical makeup including the content of fluoride ions.16 The efficacy of exogenous fluoride
substances varies according to the type, concentration, and pH of the preparation
used. Nowadays, the application of fluoride varnishes, which by inhibiting enamel
demineralization play a significant role in caries reduction, is considered the most
effective method of fluoride supply.17-19 The mechanism of topically applied
highly concentrated fluoride involves the dissolution of the most external enamel
layers and repeated precipitation of calcium fluoride bound with enamel mainly as
CaF2 or a CaF2-like compound. These compounds, constituting a fluoride
reservoir, are believed to be responsible for the elevated concentration of fluoride
ion in the immediate surroundings of teeth.20
The varnishes Duraphat® and Fluoride Protector®, commonly available in our
country were used in the present study to evaluate the prophylactic effects. Their
prophylactic effect was found to depend more on the number of procedures than
on the type of varnish. Duraphat® with higher fluoride concentration was more
effective in the three-fold application, while the efficacy of Fluoride Protector®
increased with an increased number of procedures. Studies of Attin et al.21 have
shown that varnishes with higher fluoride content and an additional amount of
calcium fluoride deposit larger amounts of structurally bound fluorides soluble in
KOH than varnishes with lower fluoride concentration; however, the differences
disappear after a longer time of action.
The mean daily enamel erosion progression after the three-fold application of
Duraphat® was reduced after the six-fold treatment. Similar results were obtained
using Fluoride Protector®. Xonga et al.14 evaluated eroded teeth following the
application of a commercial 33.33% NaF preparation, compared with untreated
teeth. The results showed no significant differences in erosion progress between
fluoridated and non-fluoridated teeth, with the mean daily enamel erosion rate
being 1 µm after five months. The data suggest that fluoride preparations per se
are not able to secure complete protection against erosive factors. They also seem
52
Research report
Fluoride 39(1)49–52
January-March 2006
Fluoride varnishes for protection against dental erosion
Waszkiel, Marczuk-Kolada, Grądzka-Dahlke
52
to indicate that fluoride varnishes are more efficient in preventing enamel
dissolution than NaF solutions, which has already been reported in literature.19
Enamel erosion lesions are due to the action of acids which possess stronger
demineralization properties than dental caries. Therefore, since topical fluoride
preparations that play an important role in caries prophylaxis may not be effective
in preventing acid erosion, formulations of varnishes with higher fluoride
concentrations should probably be considered for application.
In conclusion, we found: (1) application of fluoride varnishes reduces enamel
susceptibility to the action of erosion-inducing factors; (2) the number of
varnishing procedures determines the efficacy of varnishes.
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