In the introduction, the author explains the microbiological aetiol-
ogy of periodontitis (although the references may be too old), and
justifies the adjunctive use of Antimicrobial Photodynamic therapy
(aPDT) in periodontal therapy, based on their antimicrobial effects
and on the limitations of other adjunctive therapies (such as local
and systemic antimicrobials). Among these limitations, the increase
in bacterial resistance and biofilm resistance are enumerated,
although the second one should not be included, when these thera-
pies are used as adjuncts to mechanical debridement.
This review aimed to compare scaling and root planing (SRP) plus
aPDT versus SRP alone. An extensive search lead to the evaluation of
14 full-text papers, and four of them were excluded due to the use of
‘high-level lasers’, a criterion that was not mentioned in the paper.
Finally, four papers were included, two of them performed by the
same research group.
The studies presented some heterogeneity, with one of them fol-
lowing a split mouth-design. One of the most important issues of
the review is that it is not reported how many sites were measured
in each patient and how the sites were selected. In addition, it seems
that the author has performed a site-based analysis, according to the
data provided in the figures.
Meta-analyses of the four studies were performed for the primary
outcome variable (Clinical Attachment Level –CAL- changes) and
one of the secondary outcomes (Probing Pocket Depth –PPD- chang-
es). Surprisingly, gingival recession was selected as one of the vari-
ables in the inclusion criteria, when it just represents the difference
between CAL and PPD. Bleeding on probing (BOP), a more mean-
ingful clinical variable, and microbiological variables (highlighted
in the introduction) were only marginally considered.
A significant difference of 0.29mm in CAL change was calcu-
lated in the meta-analyses, and a non-significant difference of
0.11mm in PPD change, both favouring the adjunctive therapy,
at the 12-week evaluation. The differences were of small magni-
tude with no associated adverse effects. However, the differences
among the studies were obvious, with two studies with a clear
impact in both variables 1,2 , and two studies (those performed
by the same group) with smaller impact and minor differences
among groups.3,4 The first two studies had a 12-week follow up,
while the last two had a 24-week duration, although the 12-week
results were included in the meta-analysis. In addition, one of
last two studies included patients in supportive periodontal ther-
apy (already treated and following a secondary prevention pro-
gram), despite the inclusion criterion of the review of ’untreated
In the discussion, the limitations of this systematic review are
acknowledged, including the design of the review with just one
examiner. No mention is made of the need for patient-based analy-
sis as opposed to site-based analysis. Site-based analysis is not con-
sidered adequate in periodontal therapy, since all the sites from
the same patient are influenced by the same systemic factors (such
as smoking or genetics), and therefore all the sites from different
patients should not be combined. In addition, 12 weeks of follow-up
may only be considered as short-term. Longer follow-ups are needed
to define the real benefits of a therapy.
In a recent commentary5, another systematic review on the topic
was evaluated.6 It included five papers, three papers in common with
Photodynamic therapy for chronic periodontitis
Photodynamic therapy as an adjunctive treatment for chronic periodontitis:
a meta-analysis. Lasers Med Sci 2010; 25; 605-613. Epub 2009 Dec 19.
Address for correspondence: MA Atieh, Sir John Walsh Research Institute,
School of Dentistry, University of Otago, PO Box 647, Dunedin, New Zealand.
Data sources MEDLINE, EMBASE, The Cochrane Oral Health
Group’s Trials Register, CENTRAL, UK National Research Register,
ISI Proceedings, hand search of relevant journals for 2000-2008.
References from selected articles and contact with authors.
Study selection Randomised controlled trials in any language
comparing scaling and root planing (SRP) alone and SRP with PDT in
patients with chronic periodontitis, with a mean follow up of at least
12 weeks. The primary outcome measure was the change in clinical
attachment loss (CAL). Secondary outcomes were changes in probing
depth (PD) and gingival recession (GR).
Data extraction and synthesis Data were extracted by a single
reviewer using a standard extraction form. Quality was assessed using
both the Jadad scale and the allocation concealment component of the
Cochrane risk of bias tool. Meta-analysis was conducted using
the random effects model. Heterogeneity was assessed using the
chi-squared-based Q statistic method and Higgins’ I2 test.
Results Four trials with 101 participants were included. The risk of
bias of these trials was considered to be moderate. The mean difference
in CAL at 12 weeks was 0.29 mm (95% CI 0.08–0.50, p=0.007).
Heterogeneity was high using both the Chi2 and I2 tests.
Conclusions The review suggests there may be a minor improvement
in clinical attachment loss at 12 weeks. It is unclear whether this is a
clinically meaningful improvement.
Question: Does photodynamic therapy
(PDT) improve outcomes in the treatment
78 © EBD 2011:12.3
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