Photomechanical effect on Type I collagen using pulsed diode laser

Ex vivo study of Ho:YAG and thulium fiber lasers for soft tissue surgery: which laser for which case?

The goal of this study was to assess the ablation, coagulation, and carbonization characteristics of the holmium:YAG (Ho:YAG) laser and thulium fiber lasers (TFL). The Ho:YAG laser (100 W av.power), the quasi-continuous (QCW) TFL (120 W av.power), and the SuperPulsed (SP) TFL (50 W av.power) were compared on a non-frozen porcine kidney. To control the cutting speed (2 or 5 mm/s), an XY translation stage was used. The Ho:YAG was tested using E = 1.5 J and P_av = 40 W or P_av = 70 W settings. The TFL was tested using E = 1.5 J and P_av = 30 W or P_av = 60 W settings. After ex vivo incision, histological analysis was performed in order to estimate thermal damage. At 40 W, the Ho:YAG displayed a shallower cutting at 2 and 5 mm/s (1.1 ± 0.2 mm and 0.5 ± 0.2 mm, respectively) with virtually zero coagulation. While at 70 W, the minimal coagulation depth measured 0.1 ± 0.1 mm. The incisions demonstrated zero carbonization. Both the QCW and SP TFL did show effective cutting at all speeds (2.1 ± 0.2 mm and 1.3 ± 0.2 mm, respectively, at 30 W) with prominent coagulation (0.6 ± 0.1 mm and 0.4 ± 0.1 mm, respectively, at 70 W) and carbonization. Our study introduced the TFL as a novel efficient alternative for soft tissue surgery to the Ho:YAG laser. The SP TFL offers a Ho:YAG-like incision, while QCW TFL allows for fast, deep, and precise cutting with increased carbonization.

Use of Er:YAG laser in the treatment of vulvar lichen sclerosus

Objective

The aim of this research was to evaluate the efficacy and safety of Er:YAG lasers to improve signs and symptoms of vulvar lichen sclerosus.

Methods

The study population consisted of 28 women with symptomatic vulvar lichen sclerosus. Three nonablative, thermal-only Er:YAG laser treatment sessions (7 J/cm², 2 Hz, 7 mm spot) were performed at 4-week intervals. Each patient was asked about the presence of symptoms, such as itching, pain, and coital pain. Clinical diagnosis was established on the basis of the presence of lesions such as hypopigmentation, ecchymosis, hyperkeratosis, excoriations, or fissures. The affected areas were divided by zones (clitoris, introitus, labia minora, labia majora, perineum, labial fusion, and effacement) and were visually evaluated. Based on the presence of symptoms, lesions, and affected zones, a scale with a maximum of 14 scores was established for use before and after treatment. The impact of lichen sclerosus on patients' lives before and after treatment was evaluated with an 11-point visual analogue scale, and treatment discomfort was assessed at each session.

Results

After analysis of each scoring component, individual statistically significant reductions were observed in itching, pain, ecchymosis, excoriations, and hypopigmentation.

Conclusion

The Er:YAG laser is a safe, well tolerated, and effective method for the adjuvant treatment of vulvar lichen sclerosus. Three sessions with monthly intervals using the indicated parameters can quantifiably reduce the impact of lichen sclerosus on patients' lives.

Effects of Diode Laser, Gaseous Ozone, and Medical Dressings on Enterococcus faecalis Biofilms in the Root Canal Ex Vivo

The objective was to compare the antibacterial effects of adjunctive disinfection using diode laser and gaseous ozone compared to the medical dressings calcium hydroxide (Ca(OH)₂) and chlorhexidine gel (CHX-Gel) on Enterococcus faecalis biofilms in human root canals ex vivo. Root canals of 180 human extracted teeth were infected by E. faecalis and divided into 3 main groups (G): G1, control; G2, instrumentation and irrigation using 0.9% NaCl; G3, instrumentation and irrigation using 1% NaOCl. In each main group, the following treatments were applied: gaseous ozone, diode laser, and medical dressings of Ca(OH)₂ or CHX-Gel for 7 days (n = 15). Reduction of colony forming units (CFUs) inside the root canal of planktons and frequencies of adherent bacteria after treatment were calculated. Bacterial reduction was significantly affected by the irrigation protocol (p < 0.0005) and the disinfection method (p < 0.0005), and a significant interaction between both factors could be observed (p < 0.0005; ANOVA). In G3 (instrumentation using 1% NaOCl), no significant effect of disinfection methods could be demonstrated on planktonic bacteria (p = 0.062; ANOVA) and frequencies of adherent bacteria (p > 0.05; chi-square test). Instrumentation and irrigation using NaOCl combined with ozone or laser application resulted in comparable bacterial reduction on E. faecalis to the application of medical dressings.