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OA Maced J Med Sci. 2015 Sep 15; 3(3):447-454. 447
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Open Access Macedonian Journal of Medical Sciences. 2015 Sep 15; 3(3):447-454.
http://dx.doi.org/10.3889/oamjms.2015.071
eISSN: 1857-9655
Stomatology
Treatment of Gingival Hyperpigmentation by Diode Laser for
Esthetical Purposes
Hanaa M. El Shenawy1*, Sherine A. Nasry1, Ahmed A. Zaky2, Mohamed A. A. Quriba2
1Orodental Division Department, National Research Centre, Cairo, Egypt; 2Medical Laser Application Department, National
Institute of Laser Enhanced Science (NILES), Cairo University, Cairo, Egypt
Citation: El Shenawy HM, Nasry SA, Zaky AA, Quriba
MAA. Treatment of Gingival Hyperpigmentation by Diode
Laser for Esthetical Purposes. OA Maced J Med Sci. 2015
Sep 15; 3(3):447-454.
http://dx.doi.org/10.3889/oamjms.2015.071
Key words: diode laser; gingival; hyperpigmentation;
melanin.
*Correspondence: Hanaa M. El Shenawy. Orodental
Division Department, National Research Centre, Cairo,
Egypt. E-Mail: dr.hanaa.shenawy@gmail.com
Received: 13-Apr-2015; Revised: 04-May-2015;
Accepted: 08-Jun-2015; Online first: 07-Aug-2015
Copyright: © 2015 Hanaa M. El Shenawy, Sherine A.
Nasry, Ahmed A. Zaky, Mohamed A. A. Quriba. This is an
open access article distributed under the terms of the
Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any
medium, provided the original author and source are
credited.
Competing Interests: The authors have declared that no
competing interests exist.
Abstract
BACKGROUND: Gingival hyperpigmentation is a common esthetical concern in patients with
gummy smile or excessive gingival display. Laser ablation has been recognized recently as the
most effective, pleasant and reliable technique. It has the advantage of easy handling, short
treatment time, hemostasis, decontamination, and sterilization effect.
AIM: In the present study we wanted to explore the efficacy of a 980 nm wavelength diode laser in
gingival depigmentation clinically by using both VAS and digital imaging method as means of
assessment.
METHODS: Diode laser ablation was done for 15 patients who requested cosmetic therapy for
melanin pigmented gums. The laser beam delivered by fiberoptic with a diameter of 320 µm, the
diode laser system has 980 nm wave lengths and 3 W irradiation powers, in a continuous contact
mode in all cases, the entire surface of each pigmented maxillary and mandibular gingiva that
required treatment was irradiated in a single session. Clinical examination and digital image
analysis were done and the patients were followed up for 3 successive months.
RESULTS: There was a statistically significant change in prevalence of bleeding after treatment, as
none of the cases showed any signs of bleeding 1 week, 1 month and 3 months after ablation. No
statistically significant change was observed in the prevalence of swelling after treatment The VAS
evaluation demonstrated that only 4 patients complained of mild pain immediately after the
procedure. No pain was perceived from the patients in the rest of the follow up period. There was
no statistically significant change in prevalence of pain immediately after treatment compared to
pain during treatment. There was a decrease in cases with mild pain after 1 week, 1 month as well
as 3 months compared to pain during treatment and immediately after treatment.
CONCLUSION: Within the limitations of this study, the use of diode laser was shown to be a safe
and effective treatment modality that provides optimal aesthetics with minimal discomfort in patients
with gingival hyperpigmentation.
Introduction
Gingival hyperpigmentation is increased
pigmentation beyond the normally expected degree of
the oral mucosa. Several physiologic and/or
pathologic factors can cause hyperpigmentation [1].
However the most common cause is physiologic or
ethnic hyperpigmentation. Physiologic
hyperpigmentation is genetically determined and is
clinically manifested as variable amounts of diffuse or
multifocal melanin pigmentation in different ethnic
groups [2].
Melanin, a brown pigment, is the most
common natural pigment contributing to endogenous
pigmentation of gingiva and is produced by
melanocytes in the basal and supra-basal cell layer of
the gingival epithelium [3]. The gingiva is the most
frequently pigmented tissue of the oral cavity [4].
Although gingival melanin pigmentation does
not represent a pathological problem, patients with a
gummy smile or excessive gingival display usually
complain of a “black gum“ and request cosmetic
therapy [5, 6].
Gingival depigmentation is a treatment to
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remove melanin hyperpigmentation of the gingiva and
various methods have been used for this procedure
with different degrees of success including
gingivectomy [7], gingivectomy with free gingival
autografting [8], electrosurgery [9], Cryosurgery [10],
chemotherapy with 90% phenol and 95% alcohol and
abrasion with diamond bur [11]. Moreover some of
these techniques are prone to side effects and
complications [12]. Recently lasers have been used to
ablate cells containing and producing the melanin
pigment [5]. The commonly used lasers for gingival
de-epithelization include semi-conductor diode, Er:
YAG Nd: YAG laser, and CO2 laser
Recent research has centered on using
pulsed diode laser (810 λ) for oral surgery of the
tongue and gingiva and to remove infected epithelium
in chronic periodontitis. The advantages of this laser
in its easy gingival reshaping, reduced need for local
anesthesia, excellent hemostasis, minimal thermal
injury of the deeper tissues and negligible post-
operative pain and inflammation [12, 13]. Moreover
there is evidence in the recent literature of successful
depigmentation using diode lasers [2].
Digital cameras produce color images that
consist of three – red (R), green (G) and blue (B) –
components, and the corresponding three spectrally-
selective images can be reconstructed and analyzed
additionally to the conventional color image [14-16].
RGB camera works as a simple multi-spectral imaging
device acquiring three spectral images at a time
where R channel can be roughly attributed to
600…700 nm spectral range, G – 500…600 nm and B
– 400…500 nm. Data fitting and estimation techniques
are then utilized to obtain estimates of hemoglobin
and melanin distribution [16]. Advantage of such
simplified approach is a possibility to acquire the
spectral image cube immediately, without time losses
due to durable signal processing [14-16].
In the present study we wanted to explore the
efficacy of a 980 nm wavelength diode laser in
gingival depigmentation clinically by using both VAS
and digital imaging method as means of assessment.
Long-term monitoring and direct visual comparison of
medical states of oral pathologies on the basis of
individual subjects can be applied. Even though
colorimetric values of the pixels in the images are in
device dependent RGB color space of the camera,
certain analyses of color properties in images
acquired with the proposed acquisition method are
possible. One such application could be to monitor
changes in gingival or teeth colors on the basis of
individual subjects over a long period of time.
Material and Methods
Fifteen patients (7 males and 8 females)
suffering from gingival hyper pigmentation in the
anterior segment of the mouth with age range from 15
to 45 years old, and free from any systematic
diseases which may have effect on healing post
operatively, was included in this study. Patients were
selected randomly from the outpatient clinic of the
National Institute of Laser Enhanced Science (NILES),
Cairo University, Egypt and assessed for eligibility by
an oral Medicine, Diagnosis and Periodontology
specialist. The patients consented to their enrollment
in the study by signing a written informed consent.
Patients were aware of the nature of
ethnic/physiological hyperpigmentation and
understood that this phenomenon had no influence on
their systemic or oral health.
Inclusion criteria was moderate to severe
bilateral melanin hyperpigmentation of the upper and
lower gingivae as given by Dummett Gupta in 1964
[17] and well maintained oral hygiene and esthetic
concerns. Exclusion criteria were: history of systemic
diseases associated with pathological
hyperpigmentation or improper delayed wound
healing (uncontrolled diabetes, autoimmune diseases,
etc.), pregnancy and lactation, untreated periodontal
disease, chronic smokers and non-compliant patients
[18].
Clinical examination
Clinical Assessment of swelling and bleeding
was done immediately after termination of laser
ablation, after 1week and 1 month and 3 months
postoperatively. The VAS [19] was used to measure
the intensity of pain experienced during and after
treatment. The VAS consisted of a horizontal line 100
mm long, anchored at the left end by the descriptor
‘‘no pain’’ and at the right end by ‘‘unbearable pain.’’
The patient placed a mark to coincide with the level of
pain. The distance of this point, in millimeters, from
the left end of the scale was recorded and used as the
VAS score. Scores were calculated as: 0 =no pain;
0.1 to 3.0 cm (1 to 30 mm) = mild pain; 3.1 to 6.0 cm
(31 to 60 mm) = moderate pain; 6.1to 10 cm (61 to
100 mm) = severe pain
Digital examination
The change in gingival pigmentation was also
studied using comparative clinical photographs. Four
photos were taken for each patient, the first before
laser application, then one weak, one month, and 3
months after laser treatment comprising a total of 60
photos for 15 patients.
Image analysis was done by using a high
resolution digital camera (Nikon Coolpix 1810).
Photos were taken by the same camera and with the
same zoom and the same programmed chair position
to ensure standardization. The distance between the
camera and the patient was also standardized at 3
feet by placing the camera over its tripod stand. The
El Shenawy et al. Treatment of Gingival Hyperpigmentation by Diode Laser
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OA Maced J Med Sci. 2015 Sep 15; 3(3):447-454. 449
triple feet of the camera stand were then marked on
the floor using permanent marker.
The RGB (red, green and blue) value was
analyzed using Adobe Photoshop CS5 version to
analyze the histogram of the digital photographs.
Laser procedure
The diode laser used in this study has
fiberoptic delivery system with beam diameter of 320
µm, 980 nm wave length and was operated at a 3 W
irradiation power, in a continuos contact mode.
Before applying the laser, the operating staff
and the patients wore special laser-protective eye
glasses corresponding to laser wavelength. Highly
reflective instruments or instruments with mirrored
surfaces were avoided [20].
In all cases, the entire surface of each
maxillary and mandibular gingiva that required
treatment was irradiated in a single session.
Precautionary postoperative instructions such
as avoiding smoking and eating hot and spicy food for
the first 24 hours were given to all patients. Also
patients were advised not to traumatize the area
during the healing period which is 4 -7 days after
treatment and to take analgesics ibuprofen 200 mg
after the surgery and to continue with the medication
for the next 3 days if pain was experienced.
After application of topical anesthesia
(lignocaine hydrochloride), laser ablation was started
from the mucogingival junction working toward the
free gingival margin, including the papillae in a
continuous contact mode with overlapping circles and
the fiber tip was continuously moved across the site to
avoid heat accumulation at any site. The water spray
helped to rinse the tissue as ablation proceeded. Then
the area was wiped with gauze soaked in normal
saline. The same procedure was repeated till no
pigments remained.
No periodontal dressing was placed and no
antibiotics were prescribed. The procedure was
completed within 20 to 25 minutes. The patients were
then followed up for 3 subsequent visits, after one
week, one month then 3 months.
Figure 1: Preoperative view showing diffuse melanin pigmentation
Statistical analysis
Qualitative data were presented as
frequencies (n) and percentages (%). Cochrane’s Q
and Friedman’s tests were used to study the changes
after treatment in different qualitative data. Age data
were presented as mean, standard deviation (SD),
minimum and maximum values. The significance level
was set at P ≤ 0.05. Statistical analysis was
performed with IBM® SPSS® Statistics Version 20 for
Windows.
Data collected from the pixel profile program
was collected, tabulated and analyzed using SPSS
V.16 and Gragh PAD Prisn V.6.
Clinical Results
The 980 nm diode laser used with water spry
effectively ablated the epithelial tissue exhibiting
melanin pigmentation. Most of the melanin
pigmentation was removed with minimal penetration
into the tissue. The procedure time ranged from 20 to
25 min depending on the severity and extent of
pigmentation. In all patients immediately after the
procedure, gingival connective tissue was exposed
with slight bleeding. The treated area appeared white
due to the formation of protein coagulum and there
was no need to apply a periodontal dressing. The
treated surface did not exhibit major thermal changes,
such as marked coagulation and carbonization. A
white fibrin slough was seen after 24 hours. At 1
week, the treated gingiva showed fast epithelization
with a healthy appearance, but immature healing, in
all cases (Fig. 2).
Figure 2: Post operative view 1 week later
At the second week the epithelium showed a
non-keratinized translucent appearance and the laser-
irradiated gingiva appeared reddish compared to the
neighboring untreated gingiva. At 1 month, complete
healing with tissue maturation was observed and the
gingiva exhibited normal appearance (Fig. 3).
Postoperative side effects such as gingival recession
were not observed in any of the cases during the 3
months observation period.
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Figure 3: Postoperative view one month later
The treated sites showed uneventful wound
healing without any severe post-surgical
problems.There was obvious change in the amount of
the pigmented areas in the patients gingiva before
and immediately after the operation and during the
post-operative visits (Fig. 1-4). Also the digital
analysis of the photographs by using Photoshop
software showed a decrease in the pigmentation by
RGB factor. All of the melanin pigmentation was
removed with minimal penetration into the tissue.
There were no areas of carbonization and the
bleeding was controlled. During the three months
follow up no signs of re-pigmentation were observed.
The achieved results were satisfactory for
patients and the operator and met the patient’s
expectations.
Statistical analysis
Qualitative data were presented as
frequencies (n) and percentages (%). Cochrane’s Q
and Friedman’s tests were used to study the changes
after treatment in different qualitative data.
Figure 4: Postoperative view three month later
Numerical data were presented as mean and
standard deviation (SD) values. Data were explored
for normality using Kolmogorov-Smirnov and Shapiro-
Wilk tests. All data showed parametric distribution
except for (Y) and (H) values.
For parametric data, repeated measures
ANOVA test was used to study the changes by time.
Bonferroni’s post-hoc test was used for pair-wise
comparisons when ANOVA test is significant. For non-
parametric data, Friedman’s test was used to study
the changes by time. Wilcoxon signed-rank test was
used for pair-wise comparison when Friedman’s test
is significant. Bonferroni’s adjustment was applied for
the pair-wise comparisons.
The significance level was set at P ≤ 0.05.
Statistical analysis was performed with IBM® SPSS®
Statistics Version 20 for Windows.
Results
Base line characteristics
The present study was conducted on 15
patients; 7 males (46.7%) and 8 females (53.3%). The
mean ± standard deviation (SD) values of age were
29.9 ± 7.0 years with a minimum of 18.0 years and a
maximum of 40.0 years old. Twelve cases (80%) had
moderate pigmentation while three cases (20 %) had
severe pigmentation.
Table 1: Frequencies (n), percentages (%) and results of
Cochrane’s Q test for the comparison between bleeding before
and after treatment
Bleeding
Immediate
after
treatment
1 week
1 month
3 months
P-
value
n
%
n
%
n
%
n
%
No
bleeding
12
80.0
15
100.0
15
100.0
15
100.0
0.029*
Slight
bleeding
3
20.0
0
0.0
0
0.0
0
0.0
*: Significant at P ≤ 0.05
There was slight bleeding in only 3 cases
immediately after treatment, while the remaining
cases showed no bleeding signs. There was a
statistically significant change in prevalence of
bleeding after treatment, as none of the cases showed
any signs of bleeding 1 week, 1 month and 3 months
after ablation (Table 1, Fig. 1).
Figure 1: Bar chart representing bleeding before and after treatment
No statistically significant change was
observed in the prevalence of swelling after treatment
as only two cases displayed signs of swelling
immediately after treatment (Table 2, Fig. 2).
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Table 2: Frequencies (n), percentages (%) and results of
Cochrane’s Q test for the comparison between swelling before
and after treatment
Swelling
Immediate after
treatment
1 week
1 month
3 months
P-value
n
%
n
%
n
%
n
%
No swelling
13
86.7
15
100.0
15
100.0
15
100.0
0.112
Slight swelling
2
13.3
0
0.0
0
0.0
0
0.0
*: Significant at P ≤ 0.05
From the VAS evaluation only 4 patients
complained of mild pain immediately after the
procedure. No pain was perceived from the patients in
the rest of the follow up period. There was no
statistically significant change in prevalence of pain
immediately after treatment compared to pain during
treatment. There was a significant decrease in cases
with mild pain after 1 week, 1 month as well as 3
months compared to pain during treatment and
immediately after treatment (P= 0.08) (Table 3, Fig.
3).
Figure 2: Bar chart representing swelling before and after treatment
Laser parameters (R, G, B)
To study the change in gingival color, a total
of 60 photos where included for image analysis with
the pixel profile program to detect the change of the
RGB of the image before treatment 1 week, 1 month
and 3 months post treatment for each patient.
Table 3: Frequencies (n), percentages (%) and results of
Cochrane’s Q test for the comparison between pain before and
after treatment
Pain
During treatment
Immediate after treatment
1 week
1 month
3 months
P-value
N
%
N
%
n
%
n
%
n
%
No pain
11
73.3
12
80.0
15
100.0
15
100.0
15
100.0
0.008*
Mild pain
4
26.7
3
20.0
0
0.0
0
0.0
0
0.0
*: Significant at P ≤ 0.05
Data collected from the pixel profile program
were tabulated and analyzed using SPSS V.16 and
Gragh PAD Prisn V.6 then Photoshop CS5 was used
to cut the photos. A multiple comparison test was
done to test the relation between visits.
Concerning the component R, there was no
statistically significant difference between the four
visits in the change of the red color for haemoglobin
(P = 0.156), while, there was statistically significant
difference between the four visits in the green color for
cytoplasm (P = 0.012), and a highly statistically
significant difference was found between the four
visits regarding the blue color for melanin component
B (P = 0.000).
Figure 3: Bar chart representing pain before and after treatment
Discussion
Melanin pigmentation of the gingiva may be
seen across all races, at any age and without gender
predilection. Although it does not present a medical
problem, complaints of black gum and a demand for
depigmentation is common. Many techniques have
been tried for depigmentation.
Table 5: Descriptive Analysis for Hyperpigmentation PIXELES
analysis
Color Elements
Visits
Pixel (Mean ± SD)
P value
R (red)
Pre treatment
175.8 ± 21.52
Ns
Week later
201.61 ± 26.58
Month later
184.9 ± 36.45
3 Months later
184.67 ± 36.83
G (green)
Pre treatment
125.34 ± 23.05
**
Week later
98.48 ± 24.83
Month later
107.3 ± 19.74
3 Months later
107.12 ± 19.74
B (blue)
Pre treatment
128.2 ± 23.27
***
Week later
83.35 ± 33.26
Month later
104.2 ± 19.01
3 Months later
104.1 ± 18.97
Ns = non significant; ** = significant; *** = highly significant.
Recently laser ablation has been recognized
as one of the most effective, comfortable and reliable
techniques for gingival depigmentation [21]. Gingival
depigmentation performed in this study was carried
out by a 980 nm and a 4 W irradiation power settings
diode laser (quanta laser system made in Italy 980 nm
class 4 laser) as it has near optimal absorption for
melanin and hemoglobin Moreover in comparison with
Er: YAG, diode laser offers the advantage of a
successful and safe application, being able to prevent
bleeding, limit postoperative inflammation and pain
and favor healing of gingival mucosa [12].
In the present study minimal side effects such
as the very slight coagulation on the treated surface
without major thermal side effects such as
carbonization and severe coagulation that could
interfere with wound healing process was possible
with 980 nm diode laser.
The procedure was done in a contact mode
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allowing good tactile sensation and precision while
operating. Clinical results indicating a safe, effective
and practical melanin pigmentation ablation have
been reported with this contact mode. Using the
contact mode with water spray was reported to
achieve precise irradiation, good tactile sensation and
reduced thermal effect in a clean operating
environment [4, 5, 22].
Moreover complete de-epithelization requires
that the instruments are used in contact mode, in
order to get optimal control of the laser beam without
damaging the neighbouring teeth, and alveolar bone
[23]. The effectiveness of this method was confirmed
in the present study.
The white fibrin slough seen in after 24 hours
in all patients is due to the relatively thick coagulation
layer on the treated surface produced by the “hot tip”
of the diode laser fiberoptic. This is a normal
characteristic of a laser wound during the first several
days of healing. Mild pain, swelling and bleeding were
observed by some patients immediately after surgery,
while these inflammatory signs subsided during the
whole follow-up periods. The lack of bleeding after
laser treatment can be attributed to the property of
lasers to coagulate blood vessels and thereby assist
in providing a relatively dry surgical field [11]. Laser is
absorbed by pigments in the soft tissue, thus making it
an excellent hemostatic agent [20]. The slight
bleeding observed by some patients after surgery
might be due to the laser beam penetrating deeper
than required. This is in accordance with Kishore et al
2014 who observed that the bleeding was directly
correlated with the depth of ablation [24]. The use of
water enhanced the visualization of the operative field
and minimized heat generation by cooling the
irradiated area and absorbing excessive laser energy
[4].
It was theorized that the protein coagulum
formed on the wound surface as a result of irradiation
might act as a biological wound dressing sealing the
ends of sensory nerve endings. In a study comparing
the VAS score for patients treated with laser was
lower compared to patients treated with scalpel
surgery and electrosurgery, indicating that laser
procedure produced less pain and discomfort The lack
of swelling after laser treatment is in line with Khakhar
et al who reported complete removal of the gingival
epithelium without causing microvessel dilatation and
is possibly related to the direct vasomotor effects
and/or deactivation of local pro-inflammatory
mediators by the diode laser light causing microvessel
narrowing [25]. The mild inflammatory signs
manifested as swelling and bleeding observed
immediately after surgery by a few patients might be
because of the deep pigmentation in these patients,
while the pain observed during and immediately after
surgery might be attributed to a low threshold of pain
in these cases. Most adverse effects and
complications of laser treatment can be predicted by
understanding that they are mainly due to collateral
damage of normal adjacent structures.
Successful treatment following laser ablation
of hyper-pigmented areas was evident by the
uneventful healing of the gingiva and complete
regeneration resulting in a healthy pink firm
appearance. These findings confirm and extend the
previous data on the successful application of laser
techniques for the treatment of gingival
hyperpigmentation [5]. Photomodulation effects of
laser were shown to help in stimulating the fibroblasts,
angiogenesis and accelerating the lymphatic flow,
which enhances repair and regeneration. In addition
the bactericidal effect of laser related to the
generation of reactive oxygen species may also add
to the faster healing in a relatively sterile environment
[26].
The laser procedure was acceptable to the
patients as the procedure took less time and was
comfortable because the treated area required no
painful injections and patients experienced no
potoperative pain and injections after being dismissed.
Similar results were reported by other studies who
stated that diode laser presented advantages in terms
of less discomfort /pain during post-therapy period
and a reduction of treatment chair time [27, 28].
Digital color imaging acquisition is commonly
comprised of three broadband filtered images (red,
green, blue) approximating the light sensitivity of the
cones in the human eye. The blue color channel is the
component of the RGB color system that best
represents the dark shade of melanin, the red
represents the heamoglobin and the green represents
the cytoplasm. This means that the pixels of the
image can be interpreted as shinning points with
intensities of color that can be decomposed into the
RGB channels. The index values derived from digital
images depends on the camera used as well as on
the circumstantial conditions, such as the distance
from objects and illumination [29].
Digital image analysis is commonly applied for
studying skin lesions [14, 29, 30], however to our
knowledge this is the first study to use this type of
analysis on intraoral mucosal lesions.
In the present study photos were taken by the
same camera and with the same zoom and the same
programmed chair position to ensure standardization.
The distance between the camera and the patient was
also standardized at 3 feet by placing the camera over
its tripod stand.
Results demonstrated no statistically
significant difference between the four visits in the
change of the red color, although there was a slight
increase in the red component in the first week after
ablation denoting the active healing process as
granulation tissue appeared red in color due to the
pigment hemoglobin content in the blood. In a study
on the effect of nanosecond-domain laser pulses on
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OA Maced J Med Sci. 2015 Sep 15; 3(3):447-454. 453
the pigmentary system of the skin, each wavelength,
melanosomes were ruptured within keratinocytes and
melanocytes, with cytoplasmic and nuclear
alterations. Delayed epidermal depigmentation
occurred, followed by gradual repigmentation [31].
Statistical anlaysis in the present study revealed
significant difference between the four visits in the
green color (P =0.012) caused by pixel changes,
denoting alterations in the cytoplasmic content.
A highly statistically significant difference was
found between the four visits regarding the blue color
component, denoting the significant decrease in the
amount of pigmentation after laser ablation then the
melanin pigment amount became constant during the
next follow up sessions indicating that there was no
repigmentation during the follow up period.
However, because of the short follow-up
period in this study, these results may not be
conclusive. In most techniques partial repigmentation
appeared in about half of the patients after 2-4 years
of treatment [5]. As the success of depigmentation
procedure does not only rely on the amount of
depigmentation achieved but also by the time taken
for repigmentation to appear , and because the
postoperative follow-up period of this study was short,
further studies with prolonged follow up is advised.
In conclusion, within the limitations of this
study, the use of a diode laser was shown to be a safe
and effective treatment modality to provide optimal
aesthetics with reduced discomfort to the patients
during the treatment for gingival hyper pigmentation
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