In this study, we tried to brighten out not only if Er,Cr:YSSG laser could resolve gingival
hyperpigmentation but also which power of this laser could be the best. We had additional
purposes in the present study:
First, to apply defined indices to clearly show the Er,Cr:YSSG laser effects on gingival
hyperpigmentation and to compare with other studies.
Second, to compare patients with themselves and with other patients in the way of gingival
Third, to follow-up patients for a 6-month period and evaluate pigmentation recurrences.
In order to address our aims, we designed a split mouth clinical trial which randomly
allocated to treated and untreated and also 2.5 watts and 4.5 watts Er,Cr:YSSG laser in 4
quarters. We used Dummett (113) and Hedin (114) indices for gingival pigmentation which
are previously described to evaluate color intensity and extent of pigmented area,
respectively. Furthermore, visual analog scale (VAS) (115) was used in order to assess the
amount of pain perception of patients due to laser treatment.
Up to our knowledge, there are 5 studies which evaluate Er,Cr:YSSG laser on gingival
hyperpigmentation (92, 105-108). They recruited between 1 to10 patient/s and the studies
was done in Islamic Republic of Iran, Iraq, Turkey, and Thailand countries. The follow-up
period of patients varied between 4 weeks to 12 months.
In our study, Dummett oral pigmentation index (DOPI) (113) was improved significantly
when patients treated with 2.5 watts Er,Cr:YSSG laser after 7 days and 1, 3, and 6 months in
comparison to before treatment (p=0.002, p=0.003, p=0.003, and p=0.003, respectively).
Additionally, Dummet index was improved significantly in 6-month follow-up in comparison
to 7-day and 1-month follow-ups (p=0.002 and p=0.034, respectively).
Also Hedin index (114) was improved significantly with 2.5 watts Er,Cr:YSSG laser in all
mentioned follow-up periods in comparison to before treatment (p=0.002 for each). In 6-
month follow-up, Hedin index was improved significantly in comparison to 7-day, 1-month,
and 3-month follow-ups (p=0.023, p=0.038, and p=0.046, respectively).
Almost all similar studies with Er,Cr:YSSG laser were case reports and the researchers
describe the gingiva pigmentation condition. However, general results were similar to our
In Berk et al. (92) study, 1.5-1.75 watts Er,Cr:YSSG laser was used for gingival
hyperpigmentation in two patients. They did not use any specific index to describe their
results; However, they found gingiva completely lacking of pigmentation in both cases with a
small reddish part in maxillary gingiva in one case.
In Fekrazad and Chiniforush (105) case report, they applied a 1.5 watt Er,Cr:YSSG laser for
a black gingiva in right upper jaw. They mentioned complete healing was observed in 4-
week follow-up. Unfortunately, no defined index was used to describe the gingiva
Abdullah and Al-shmaah (106) had studied 10 patients with gingival pigmentation. They
found that 2-2.5 watts Er,Cr:YSSG laser could improve Dummett index mean score from 3 to
0.5, immediately after treatment. The patients examined every week and it was observed that
Dummett index mean score improved to 0.4, 0.2, 0, 0, and 0 in 1 to 5 weeks follow-ups
In other studies, with different lasers, depigmentation results were similar to ours. Basha et
al. (116) observed 3 watts Nd:YAG (1064 nm) laser could significantly decrease Dummett
index after 6 month in comparison to before treatment (p0.05).
Although gingival depigmentation is an important measure to assess the rule of various
methods in treatment of gingival pigmentation, pigmentation recurrence may limit their
benefits. Pigmentation recurrence or repigmentation is a usual concern in depigmentation
methods and extent, intensity and time of recurrence influence the quality of a measure, e.g.
In our study, we found 5 cases (41.7%) with repigmentation in both 2.5 (cases #1, 2, 4, 5, and
11) and 4.5 (cases #2, 4, 5, 8, and 11) watts Er,Cr:YSSG laser.
We found only one case with repigmentation in 30-day follow-up in 2.5 watts group (case
#11). Considering Dummett and Hedin indices, this case had 100% recurrence in
pigmentation intensity since 30-day follow-up and 33.3% recurrence in pigmentation extent
since 3-month follow-up. However, in the other side of gingiva which was treated with 4.5
watts, repigmentation occurred only in 6-month follow-up (100% in intensity and 33.3% in
For the remaining of cases we found 33.3-66.7% recurrence in pigmentation intensity and
25-50% in pigmentation extent.
Various studies reported different rate of repigmentation in different time intervals.
Therefore, it is not completely understood why repigmentation occurred in some cases and
not occurred in the remaining.
As an example, Nakamura et al. (88) found no repigmentation with CO2 laser after 12
months and only 4 patients (out of 10) had repigmentation after 24 months. Additionally,
Berk et al. (92) and Kusakci (108) found no repigmentation in Er,Cr:YSSG laser treatment
after 6 months in their case reports.
On the other hand, Suthprasertporn (107) found slight repigmentation in one case (out of 2)
when depigmented with Er,Cr:YSSG laser after 11 months.
Also, Basha et al. (116) found Nd:YAG treatment result in repigmentation after 6 months.
Both Dummett index mean scores of 2.5 and 4.5 watts Er,Cr:YSSG laser after 6 months in
our study was lower than study (0.58±0.66 and 0.5±0.67 vs. 0.8±0.41).
We had also smaller repigmentation size considering Hedin index at 6-month follow-up, in
both 2.5 and 4.5 watts Er,Cr:YSSG laser than Nd:YAG laser treatment in Basha et al. (116)
study (0.58±0.66 and 0.58±0.79 vs. 0.8±0.41).
However, Basha et al. (116) observed that Hedin and Dummett indices score significantly
decreased in 6-month follow-up in comparison to before treatment (p