Laser therapy and light sources for labial lentigines in patients with Peutz-Jeghers syndrome.

Labial lentigines associated with Peutz-Jeghers syndrome are challenging and represent a cosmetic problem. Laser and intense-pulsed light sources (IPLS) can be used to treat these macules. However, there are few guidelines regarding the different types of protocols found in the literature. Thus, the purpose of this study was to review the pertinent literature on lasers and IPLS as therapy for labial lentigines in patients with Peutz-Jeghers syndrome. A detailed literature search was conducted in seven databases (Cochrane Library, Embase, Lilacs, PubMed, SciELO, Scopus and Web of Science) to November 2020. Data were extracted and analyzed from selected studies including study design, sample size, participants' skin color, age, and gender, parameters of the laser or IPLS used, interval and total sessions of laser application, results obtained, follow-up time and side effects. Thirteen out of 124 published studies met our eligibility criteria, covering 81 patients. Ten types of lasers and IPLS were used, and most of the sample (n = 57) was treated with Q-switch Alexandrite Laser (QSAL). The total number of sessions ranged from 1 to 12 and the interval between sessions ranged from 2 to 16 weeks. All studies have shown satisfactory results, with no further complications. The follow-up ranged from 2 to 97 months. Laser therapy and IPLS are effective in the treatment of lentigines associated with PJS. Although QSAL was used in 70.3% of the sample, different types of lasers showed comparable satisfactory results.

Photobiomodulation can prevent apoptosis in cells from mouse periodontal ligament.

Photobiomodulation (PBM) has been used to modulate the inflammatory and immune responses, pain relief, and to promote wound healing. PBM is widely used in dental practice and its cellular effects should be investigated. The aim was to evaluate if PBM changes proteins cell death-related, such as caspase-6 and Bcl-2, in periodontal ligament cells. Eighteen mice were divided in three groups (n = 6), i.e., (I) control, (II) 3 J cm-2, and (III) 30 J cm-2. Low power infrared laser (830 nm) parameters were power at 10 mW, energy densities at 3 and 30 J cm-2 in continuous emission mode, exposure time of 15 and 150 s, respectively for 4 days in a row. Twenty-four hours after last irradiation, the animals were euthanized, and their jaws were fixed and decalcified. Caspase-6 and Bcl-2 were analyzed by real-time polymerase chain reaction and immunocytochemical techniques, and DNA fragmentation was evaluated by TUNEL. Statistical differences were not significant to caspase-6 mRNA relative levels in tissues from jaws at both energy densities, but a significant increase of Bcl-2 mRNA relative levels was obtained at 30 J cm-2 group. Also, 30 J cm-2 group showed caspase-6 positive-labeled cells decreased and Bcl-2 positive-labeled cells significantly increased. TUNEL-labeled cells demonstrated DNA fragmentation decreased at 30 J cm-2. PBM can alter Bcl-2 mRNA relative level and both caspase-6 and Bcl-2 protein, modulating cell survival, as well as to reduce DNA fragmentation. More studies must be performed in order to obtain conclusive results about photobiostimulation effects using infrared low-level laser in apoptosis process as to achieve the optimum dosage.