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Clinical Efficacy of 5% Sodium Hypochlorite for Removal of Stains Caused by Dental Fluorosis

Authors:
  • Hospital Central Dr. Ignacio Morones Prieto. Universidad Autónoma de San Luis Potosí.

Abstract and Figures

The objective of this study was to evaluate the clinical efficacy of 5% sodium hypochlorite solution for removal of stains caused by dental fluorosis in young patients. A clinical trial involved 33 patients with diffuse opacities on the enamel surfaces of maxillary incisors due to effects of dental fluorosis. The protocol of treatment 3 steps: (1) cleaning and enamel etching with 37% phosphoric acid in order to eliminate the layer that covers the fluorotic enamel surface and allow better penetration of the bleaching agent, (2) application of 5% sodium hypochlorite to remove stains caused by organic material, and (3) filling the opened micro-cavities with a light-cured, composite surface sealant to prevent restaining. The whiteness of the enamel lesions before and after treatment were expressed in L*, a*, and b* color space measurements using a Minolta Chroma Meter CR300. Analysis of parameters of [symbol:see text]E (L*, a*, b*) showed that changes were observed in the L* (brightness) and a* (redness), which paralleled the [symbol: see text]E differences. There was no significant difference in the b* (yellow) parameter. The technique described in this study appears to have advantages over other methods for improving the appearance of fluorotic lesions. It is simple, low cost, non invasive so the enamel keeps its structure, relatively rapid, and safe; it requires no special materials, and it can be used with safety on young permanent teeth.
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Efficacy of 5% Sodium Hypochlorite
The Journal of Clinical Pediatric Dentistry Volume 33, Number 3/2009 187
IINNTTRROODDUUCCTTIIOONN
There has been a decline in dental caries in developed
countries over the last 2 decades because of the wide-
spread use of fluoride. Concurrent with the decline in
caries, an increase in the prevalence of dental fluorosis has
been reported.1
Dental fluorosis is a specific disturbance in tooth forma-
tion, and is defined as a chronic, fluoride-induced condition
in which enamel development is disrupted and the enamel is
hypomineralized. Clinically, dental fluorosis is seen as white
spots or opaque white lines (striations), or the tooth surface
may have a white, parchment-like appearance. The brown
stains sometimes seen in moderate-to-severe fluorosis are
due to the uptake of extrinsic stains, mainly from the diet. At
higher concentrations of fluoride, discrete or confluent pit-
ting of the enamel surface is seen, accompanied by extrinsic
stains.2Dental fluorosis is distributed symmetrically, affect-
ing mainly anterior teeth, and the severity varies among the
different types of teeth. Teeth that develop and mineralize
later in life have a higher prevalence of dental fluorosis.3
The effects of fluoride on enamel formation in man are
cumulative, rather than requiring a specific threshold dose.
These effects depend on the total fluoride intake from all
sources. The principal source of fluoride is drinking water;
many cities have large amounts of natural fluoride in their
drinking water, putting the population at risk for developing
dental fluorosis. In central and northern Mexico there are
extensive areas of endemic fluorosis. Such a city is San Luis
Potosi (SLP). Because it is located in an area where the
drinking water contains excessive quantities of natural fluo-
ride, its inhabitants are at risk for developing dental fluoro-
sis.4Also, the high prevalence of dental fluorosis in SLP can-
not be attributed only to the levels of fluoride in drinking
CClliinniiccaall EEffffiiccaaccyy ooff 55%% SSooddiiuumm HHyyppoocchhlloorriittee ffoorr RReemmoovvaall ooff
SSttaaiinnss CCaauusseedd bbyy DDeennttaall FFlluuoorroossiiss
Aurora Cárdenas Flores* / Héctor Flores Reyes ** / Antonio Gordillo Moscoso*** /
Juan Pablo Castanedo Cázares**** / Amaury de J. Pozos Guillén*****
The objective of this study was to evaluate the clinical efficacy of 5% sodium hypochlorite solution for
removal of stains caused by dental fluorosis in young patients. A clinical trial involved 33 patients with dif-
fuse opacities on the enamel surfaces of maxillary incisors due to effects of dental fluorosis. The protocol of
treatment 3 steps:(1) cleaning and enamel etching with 37% phosphoric acid in order to eliminate the layer
that covers the fluorotic enamel surface and allow better penetration of the bleaching agent,(2) application
of 5% sodium hypochlorite to remove stains caused by organic material, and (3) filling the opened micro-
cavities with a light-cured, composite surface sealant to prevent restaining. The whiteness of the enamel
lesions before and after treatment were expressed in L*, a*, and b* color space measurements using a
Minolta Chroma Meter CR300. Analysis of parameters of ¢E (L*, a*, b*) showed that changes were
observed in the L* (brightness) and a* (redness), which paralleled the ¢E differences. There was no signif-
icant difference in the b* (yellow) parameter. The technique described in this study appears to have advan-
tages over other methods for improving the appearance of fluorotic lesions. It is simple, low cost, non inva-
sive so the enamel keeps its structure, relatively rapid, and safe; it requires no special materials, and it can
be used with safety on young permanent teeth.
KKeeyywwoorrddss::bleaching, sodium hypochlorite, dental fluorosis.
J Clin Pediatr Dent 33(3): 187–192, 2009
* Aurora Cárdenas Flores, DDS Resident, Pediatric Dentistry
Posgraduate Program, Facultad de Estomatología, Universidad
Autónoma de San Luis Potosí, México
** Héctor Flores Reyes, DDS, PhD Associate professor, Endodontics
Posgraduate Program, Facultad de Estomatología, Universidad
Autónoma de San Luis Potosí, México
*** Antonio Gordillo Moscoso, MD, PhD Associate professor,
Department of Clinical Epidemiology, Facultad de Medicina,
Universidad Autónoma de San Luis Potosí, México
**** Juan Pablo Castanedo Cázares, MD, MS Associate professor,
Department of Dermatology, Hospital Central “Dr. Ignacio Morones
Prieto,” Universidad Autónoma de San Luis Potosí, México
***** Amaury de J. Pozos Guillén DDS, PhD, Associate professor,
Pediatric Dentistry Posgraduate Program, Facultad de
Estomatología, Universidad Autónoma de San Luis Potosí, México
Send all correspondence to: Amaury de Jesús Pozos Guillén, Facultad de
Estomatología, Universidad Autónoma de San Luis Potosí. Av. Dr. Manuel
Nava #2, Zona Universitaria, C.P. 78290; San Luis Potosí, S.L.P. México.
Tel: 52 (444)8262357 ext 106
E-mail: apozos@uaslp.mx
Efficacy of 5% Sodium Hypochlorite
water; other risk factors must be considered.5-7
The unesthetic discoloration of dental fluorosis is the
most prominent feature, frequently causing psychological
problems. A variety of treatment approaches have been pro-
posed for discoloration caused by dental fluorosis in young
patients, including microabrasion,8-11 direct and indirect
restorations,12 whitening toothpastes,13,14 and bleaching using
products such as acids,15-17 calcium sucrose phosphate,18 car-
bamide peroxide, hydrogen peroxide,19-21 and sodium
hypochlorite (NaOCl).18,22-24 NaOCl has been used in differ-
ent concentrations in endodontic treatment as an irrigant to
support the mechanical preparation of root canals. Studies
have demonstrated that irrigation with NaOCl is an effective
means of faciliting the removal of pulp tissue and dentinal
shavings; it also has been shown to have antimicrobial prop-
erties.25 The etch/bleach/seal technique using NaOCl as a
bleaching agent has recently been proposed as a conservative
alternative treatment, and it has shown good clinical suc-
cess.23 This study aimed to evaluate the clinical efficacy of
sodium hypochlorite 5% solution for the removal of stains
caused by dental fluorosis in young patients.
MMAATTEERRIIAALLSS AANNDD MMEETTHHOODDSS
Study subjects were recruited from the Clinic for Pediatric
Dentistry Posgraduate Program, Facultad de Estomatología,
Universidad Autónoma de San Luis Potosí, México. A clini-
cal trial involved 33 patients with diffuse opacities on
enamel surfaces of maxillary incisors due to the effects of
dental fluorosis. The study was approved by the Ethics Com-
mittee. Indications, contraindications, risks, benefits, and
alternatives of bleaching were explained to the parents or
legal guardians, and written informed consent was obtained.
Inclusion criteria were as follows: Dental fluorosis of
degrees 1 to 4 according to the Tooth Surface Index of Flu-
orosis (TSIF); 4 maxillary incisors completely erupted; all
teeth free of caries and restorations, and aged between 8 and
12 years. Exclusion criteria were: Previous bleaching treat-
ment, tooth sensitivity, periodontal disease, nonvital teeth,
history of dental trauma, and hypersensitivity to sodium
hypochlorite.
Studies were done to assess the reproducibility of record-
ing the TSIF, and the Kappa value was calculated. Fifty full-
arch tooth blocks were examined by the main examiner and
another examiner to assess interexaminer agreement. The
kappa value for interexaminer agreement was 0.90 for the.
We applied NaOCl 5% solution in this study, according to
Wright´s protocol. Briefly, the teeth were cleaned with flour
of pumice, using a rubber cup to remove all plaque, and
rinsed with water. The teeth were then isolated with a rubber
dam and each tooth was ligated to protect the soft tissues
from the bleaching agent. To allow better penetration, the
enamel surface was etched for 15 seconds with 37% phos-
phoric acid and rinsed. The NaOCl was applied to the entire
tooth surface using a cotton applicator, repeating the appli-
cation as the solution evaporated. The teeth were bleached at
one appointment in 15 to 20 minutes. To prevent organic
material from reentering the porous and hypomineralized
enamel, the teeth was sealed after achieving the optimal
bleach result using a light-cured, composite surface sealant
(Fortify, Bisco, Lombard, IL).
Whiteness of the enamel lesions were expressed in L*,
a*, and b* color space measurements using a Minolta
Chroma Meter CR300 (Chromameter, Minolta, Osaka,
Japan). We then calculated tooth color by averaging L*, a*,
and b* color parameters using the delta equation, E =
[(L*)2+ (a*)2+ (b*)2]/2, where E is the difference in
color (the more positive the value, the whiter the color), L*
is the change in lightness (the greater the L*, the whiter the
teeth), and a* and b* are chromacity values (the amount
of redness and the amount of yellowness).26,27 Color parame-
ters and the delta equation were registered before and after
treatment. For the statistical analysis, the data were analyzed
by Wilcoxon and Student
t
tests when appropriate. A proba-
bility value of <.05 was considered statistically significant.
The JMP IN v. 4.0.1 statistical program was used to analyze
the data.28
RREESSUULLTTSS
Thirty-three patients participated in this study (19 males and
14 females), ranging in age from 8 to 12 years, with mean
age of 10.9. Table 1 shows the minimum, the maximum, the
median, the mean, the SD, and values corresponding to
L* (brightness) color parameter before and after treatment.
L* is the main parameter and represents the lightness of the
teeth (the greater value of L*, the whiter the tooth). Results
after treatment with NaOCl indicated a clinically and statis-
tically significant difference (
P
< .05, Wilcoxon test). The
teeth after treatment were lighter (whiter), with the mean dif-
ference (L*) being 3.35.
188 The Journal of Clinical Pediatric Dentistry Volume 33, Number 3/2009
Table 1. L* Color Parameter before and after Treatment
L* color parameter Mean ± S.D. Median Range
Before treatment 68.95 ± 5.01 69.56 56.50–80.35
After treatment 72.30 ± 3.74 72.88 63.63–78.89
P< .05, Wilcoxon test.
Table 2. a* and b* Color Parameters before and after Treatment
Color parameter Mean ± S.D. Median Range
Before treatment a* 1.65 ± 2.43 2.05 -3.21–8.93
After treatment a* -0.04 ± 2.14 -0.85 -3.49–4.58
Before treatment b* 12.80 ± 3.95 12.86 3.70–20.97
After treatment b* 12.31 ± 2.83 12.50 4.73–18.05
P< .05, Wilcoxon test (a* parameter).
P> .05, Student ttest (b* parameter).
Table 3. Delta Equation (E) before and after Treatment
Delta equation (E) Mean ± S.D. Median Range
Before treatment 70.32 ± 4.61 71.27 59.32–80.54
After treatment 73.42 ± 3.70 73.87 64.03–80.03
P< .05, Wilcoxon test.
Efficacy of 5% Sodium Hypochlorite
The Journal of Clinical Pediatric Dentistry Volume 33, Number 3/2009 189
With respect to a* and b* color parameters (chromacity
values, the amount of redness and yellowness, respectively),
Table 2 show the results corresponding to each parameter
both before and after treatment. For the* value, a statistically
significant difference (
P
< .05, Wilcoxon) was found; how-
ever, such was not the case for b*: the mean values were sim-
ilar before (12.80) and after treatment (12.31).
Tooth color was calculated by averaging the L*, a*, b*
color parameters for each tooth before and after treatment
and calculating the differences using the delta equation (¢E).
Table 3 shows the color comparison before and after treat-
ment, which indicate a clinically and statistically significant
difference (
P
< .05, Wilcoxon ). The teeth after treatment
were whiter, with the mean difference (E) being 3.10.
Figures 1 and 2 show enamel conditions before and after
treatment in a patient. Before treatment, irregular brown
stains localized in the incisal third of both maxillary central
incisors were observed. After treatment, a satisfactory
esthetic result was observed.
DDIISSCCUUSSSSIIOONN
Widespread use of fluoride in many forms and vehicles has
been responsible for the decline in dental caries; however,
excessive quantities of fluoride consumption during enamel
formation results in structural and compositional changes in
enamel known as dental fluorosis. It can be characterized by
white spots or striations on the teeth. More severe cases
exhibit brown staining due to the uptake of extrinsic stains,
mainly from the diet. Studies suggest that the early matura-
tion stage of enamel development is the most critical for the
development of dental fluorosis.29,30
Tooth discoloration, including dental fluorosis, creates a
wide range of cosmetic problems for which the dental pro-
fession and the public expend considerable time and money
in attempting to correct.31 Owing to the psychological impact
of unaesthetic maxillary anterior teeth, dental fluorosis has
attracted considerable attention.
Bleaching techniques involve the use different sub-
stances, the most popular being the use of dentist-prescribed
peroxide and related products in different concentrations,
including home bleaching, assisted bleaching, and power
bleaching. Tooth-whitening systems are based primarily on
hydrogen peroxide or on carbamide peroxide, one of its pre-
cursors. Also, these products have been shown to improve
the clinical appearance of teeth affected by dental fluorosis.20
Side effects have been reported: tooth sensitivity and soft tis-
sue irritation being the most common adverse events. In var-
ious studies assessing the occurrence of sensitivity, 11% to
93% of patients reported this as a problem.32-35 Tooth sensi-
tivity normally persists for up to 4 days after cessation of
bleaching treatment.36 High concentrations are caustic to the
mucosa and can cause burns of gingival tissue.37 It has been
reported that carbamide peroxide agents in different concen-
trations affect the bond strength of composites to enamel and
may increase the solubility of glass ionomer and other
cements,38,39 produce changes in morphometry of gingival
ephitelium,40 penetrate into the pulp chamber to cause cyto-
toxicity,41 increase the level of DNA damage,42 and increase
the risk of carcinoma.43
Microabrasion is another alternative in the treatment of
fluorosis stains.17 This technique involves the removal of a
small amount of surface enamel and incorporates both abra-
sion with dental instruments and erosion with an acid mix-
ture. It can be successful for mild and relatively superficial
stains that do not extend into the deeper enamel layers.
In young permanent teeth that are partially erupted and
have large pulp chambers, bleaching with 5% NaOCl is an
excellent alternative for the treatment of fluorosis stains.
NaOCl is a commonly used irrigating solution that has been
shown to have both antimicrobial properties and the ability
to dissolve organic material.44,45
The efficacy of NaOCl to dissolve of organic tissue is
related to its concentration; dilution of 5.25% has been
shown to cause a significant decrease in its ability to dis-
solve necrotic tissue.46 Its effectiveness is attributed to its
ability to neutralize amino acids to form water and salt (neu-
tralization reaction). With the exit of the hydroxyl ions, there
is a reduction of pH. Hypochlorous acid, a substance present
Figure 1. Initial aspect of maxillary central incisors. Accentuated,
irregular brown stains localized in incisal third of teeth 11 and 21
diagnosed as dental fluorosis.
Figure 2. Final aspect of maxillary central incisors after bleaching
with NaOCl.
Efficacy of 5% Sodium Hypochlorite
in NaOCl solution, releases chlorine when in contact with
organic tissue as a solvent that combines with the protein
amino group, forming chloramines (chloramination reac-
tion). Hypochlorous acid and hypochlorite ions lead to
amino acid degradation and hydrolysis.47 When NaOCl con-
tacts hypomineralized and discolored enamel, it degrades
and removes the chromogenic organic material located on
the enamel surface.22
In this technique, the first critical step is the etching of
the enamel surface, which in this study took 15 seconds with
37% phosphoric acid, as opposed to the 60 seconds
described in Wright´s protocol.23 The use of phosphoric acid
denudes the microcavities containing the organic elements,
facilitating their dissolution and removal by NaOCl. The use
of 37% phosphoric acid is preferred over 16% because it
removes less enamel, and it is highly effective in etching the
enamel surface; this increases porosity and allows better
penetration of the bleaching agent. The second step is the
application of NaOCl. Care must be exercised during this
step to reduce the risk of mucosal irritation, skin injury, eye
splashes, clothing damage, and hypersensitivity and allergic
reactions.48-51 Third, the final application of sealant fills the
opened microcavities and prevents the penetration of new
organic material and restaining of the hypomineralized
lesions.22,23
Several indices have been proposed for assessing the
prevalence and severity of dental fluorosis. Each system is
used to evaluate clinical effects, and each scoring system
incorporates an ordinal measurement scale, identifying fluo-
rotic conditions ranging from very mild to severe. These
indices include Dean’s Index, Thylstrup-Fejerskov Index,
Fluorosis Risk Index, and the TSIF.52 In this study we used
the TSIF for selecting patients; this index was developed in
part to allow for the separate assessment of cosmetic fluoro-
sis (fluorotic discoloration, staining, or pitting on surfaces
visible to others.53
To evaluate changes of color after bleaching, it is neces-
sary to use a method that is sensitive to small changes in
color, and is consistent and accurate because traditional
methods of evaluation require subjective visual grading. Dif-
ferent methods have been used to evaluate changes after
tooth whitening, including indices for dental fluorosis, stan-
dard shade guides, digitized photographs, and electronic and
computer-aided systems. These indices and shade guides
require subjective visual grading, and the eye’s color percep-
tion is affected by various factors such as ambient lighting,
duration of viewing, fatigue of operator, surrounding colors,
and individual interpretation.54 Other problems in assessing
stain removal and tooth color after bleaching include
observer bias and variations in the illumination and dryness
of the dental surface, in recording opacities. Some of these
problems have been solved by using a method that gives a
consistent and accurate evaluation of tooth color, particu-
larly important in the evaluation of a system intended to
enhance tooth whiteness in clinical trials.55,56
In this study, changes in color were evaluated using a
Minolta Chroma Meter CR300 (Chromameter, Minolta,
Osaka, Japan). This device is an excellent tool in assessing
gradual changes in shade of discolored teeth by tooth
whitening because evaluations are not affected by the above
factors and they can accurately, quantitatively, and reliably
express color changes.57,58 Light-surface reflectance is
expressed in L*, a*, and b* color space measurements estab-
lished by the Comission Internationale de L’Eclairage,59 and
they are related to human color perception in all 3 color
dimensions: L* values represent color gradients from white
to black; a* values represent green to red; and b* values,
blue to yellow. For all color measurements in this study, a
Chroma Meter was used; we observed a quantitative inter-
pretation of changes of color. The changes of L*, a* para-
meters, and E were clinically and statistically significant
after treatment.
CCOONNCCLLUUSSIIOONNSS
The technique described in this study appears to have advan-
tages over other methods for improving the appearance of
fluorotic lesions. It is simple, low cost, noninvasive so the
enamel keeps its structure, relatively rapid, and safe; it
requires no special materials, and it can be used with safety
on young permanent teeth.
AACCKKNNOOWWLLEEDDGGMMEENNTTSS
Special thanks to Miguel Guerra, and Gabriela Torre for
their time and effort in assisting this study. We would like to
thank Norman Wahl, for his assistance in editing this manu-
script.
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Efficacy of 5% Sodium Hypochlorite
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... 12 In most other countries, however, dental fluorosis tends to be mild or very mild, in spite of the In line with the current trend toward minimally invasive dentistry, many clinicians advocate that teeth with cosmetically objectionable mild-to-moderate fluorosis be treated by bleaching. [13][14][15][16] In some cases, bleaching was have shown that bleaching procedure can be considered a treatment for dental fluorosis. Another consequence of a bleaching procedure is that, it will whiten the teeth color but also the white spots of fluorosis, which may appear even brighter due to bleaching causes the opaque spots to become dehydrated, making then appear whiter than they really are, which can be hidden on mild dental fluorosis, but it would be more noticeable for moderate cases. ...
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... 22 For example, chemical methods are recommended for mild tooth discoloration (such as dental fluorosis and mottled enamel from the tooth trauma during tooth development). 23 If the non-invasive methods could not fulfill the esthetic and mechanical goals, after the analysis of TRS, the minimal invasive or conventional tooth preparations should then be considered. ...
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For effective antiseptics to eliminate the virus, tests conducted on different disinfection solutions have shown that antiseptics contain compounds “ethanol” (a concentration of 6-71%) or “hydrogen peroxide” (a concentration of 0.5%) or “sodium hypochlorite” (concentration 0.1%) effective against corona viruses. According to various studies, if infected contaminated surfaces and areas are cleared with appropriate concentrations of these disinfectants, they reduce the number of infectious coronaviruses from one million pathogen particles to only 100 within one minute. On the other hand, tests showed that there are other disinfecting solutions that have been shown to be less effective in controlling Corona infection, namely benzalkonium chloride (0.05-0.2% concentration) and chlorhexidine de gluconate (0.02% concentration). Corona is a novelty in the family of viruses that have an oily membrane and is strongly affected by disinfectants, so it is very easy to eliminate them with disinfectants, such as water, soap, alcohol, ethanol, oxygen water and other disinfectants, as disinfectants of any type affect this virus and reduce its focus on surfaces, but It is preferable to be in suitable concentrations, in order to completely eliminate the virus
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In order to identify risk factors associated with human exposure to fluoride in San Luis Potosi (SLP), Mexico, a biochemical and epidemiological study was carried out in 1992. Results from the analysis of fluoride sources showed that 61% of tap water samples had fluoride levels above the optimal level of 0.7-1.2 ppm. The levels were higher after boiling. In bottled water, fluoride levels ranged from 0.33 to 6.97 ppm. These sources are important since in SLP 82% of the children drink tap water, 31% also drink bottled water, 92% prepare their food with tap water, 44% boiled all the drinking water, and 91% used infant formula reconstituted with boiled water. The prevalence and severity of dental fluorosis in children (11-13 years old) increased as the concentration of water fluoride increased. At levels of fluoride in water lower than 0.7 ppm a prevalence of 69% was found for total dental fluorosis, whereas at levels of fluoride in water higher than 2.0 ppm a prevalence of 98% was found. In the same children, fluoride levels in urine were quantified. The levels increased as the concentration of water fluoride increased. Regressional analysis showed an increment of 0.54 ppm (P < 0.0001) of fluoride in urine for each ppm of fluoride in water. Fluoride urinary levels were higher in samples collected during the afternoon (1800) when compared with sample collected during the morning (1100). Taking together all these results, three risk factors for human exposure to fluoride in SLP can be identified: ambient temperature, boiled water, and food preparation with boiled water. These factors explain the prevalence of dental fluorosis in SLP.
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This study evaluated and compared pulpal responses of teeth exposed to a 10 percent carbamide peroxide bleaching gel using short and extended application times. Of 28 subjects, four discontinued use because of thermal sensitivity. For the remaining participants, there was no difference between the pulpal readings recorded before the use of the gel or at any point during the study.