Background and aims: There are many Q-switched lasers. The Q-switched ruby laser is the one most popularly used in dermatology, aesthetic surgery and plastic surgery, to remove pigmented lesions or tattoos. Correct and regular calibration of such a system is essential. However, some clinics fail to perform this with the excuse of having no measuring instrument (MI) in their offices or treatment rooms in some of their hospitals or clinics, or even the case of well-known medical universities in Japan. The present article explains the precise calibration procedure and beam pattern checking for the Q-switched ruby systems in the first author's clinic. Rationale: In the case of treatment with a medical laser, the calibration and the irradiated pattern (IP) check of the laser being used for treatment are the most important factors for treatment efficacy and safety. If these factors change, the treatment result could be different from that expected. Such kind of data are not acceptable as scientific information for a presentation or published paper. With such unreliable results and incorrect beam pattern, replicating such a study would be impossible Regular calibration check: In our clinic, we have 2 Q-switched ruby laser systems. On a daily basis, the beam patterns, both the optical axis of the beam and its treatment footprint, are checked on dedicated printed sheets and footprint paper, respectively, at the beginning of the day and after the last procedure. Every two weeks we calibrate our systems in-house using a precise MI. Every six months we calibrate the systems in-house with the MI, and then we send the systems back to the manufacturers for calibration. Once every year, we have our MI calibrated by an accredited facility in Japan. In this way, we are not only ensuring accurate and safe treatment for our patients, but we are also producing accurate system and treatment data which can be replicated by others, the basis of evidence-based medicine.
Background and Aims: The pulsed dye laser (PDL) is recognized both as an effective treatment for vascular malformations and the as first treatment of choice for these lesions. However, PDL irradiation has poor efficacy in some patients, particularly the elderly. The present study histologically assessed such patients to try to elucidate the reason. Materials and Methods: A pulsed dye laser was used in 3 subjects in whom previous laser treatment was ineffective. Three-millimeter punch biopsies were obtained before laser treatment, 1 week and 3 months after the laser treatment. Each specimen was stained with toluidine blue and examined under light microscopy followed by electron microscopy with oolong tea extract (OTE) staining. Results: Microscopy revealed an increase in the vasculature at baseline and an increased number of dermal fibroblasts. One week post-irradiation, inflammatory cell infiltration was observed together with extensive interstitial perivascular edema. At 1 week and 3 months after laser irradiation, normal structures were observed for both blood vessels and capillary endothelial cells. Mild changes were noted in other interstitial features, but findings obtained 3 months after irradiation were almost similar to those before irradiation. Conclusions: The lower efficacy of PDL treatment in the elderly was possibly due to the markedly low amount of red blood cells in our subjects' blood vessels, a major chromophore for the PDL, was markedly low. It is possible that age-related denaturation of dermal matrix collagen plays some role in maintaining the vasculature in the interstitium with edema, and inflammatory cell infiltration could lead to the cellular release of some cytokines which favor reconstruction of the vasculature.
Introduction: The aim of this “in vitro” study was to evaluate the role of surface tension and surface roughness in the wettability, considered essential for a good adhesion, comparing Er:YAG laser - to bur-prepared dentin. Materials and Methods: Dentin surfaces of third human molars were Er:YAG laser- and bur-prepared to evaluate the effects of surface tension and roughness on wettability and interferometric analysis was used to compare the roughness of the two groups surfaces, after gold-coating them. Results: In bur-prepared samples the time taken for the water drop to spread out was approximately the same with or without metallization while, in the Er:YAG laser-prepared surfaces the spreading-out time was less than 10 seconds but longer after metallization i.e. nearly two minutes. Large differences in wettability measurements were observed because the water drop was almost immediately absorbed on the Er:YAG laser-prepared surface. The wettability test demonstrated that the porous and hydrophilic properties of Er:YAG laser-prepared surfaces are higher than bur-prepared surfaces. Conclusion: Surface tension, surface morphology and porosity had different effects on the spreading time of a water drop on both Er:YAG laser- and bur-prepared surfaces. And, while surface tension does not seem to influence the results, roughness appears to be the main parameter involved in water drop spreading, this being an indication, by the clinical point of view, to the choice of Er:YAG laser parameters in conservative dentistry.
Background: The Er:YAG laser in conservative dentistry is. good alternative to conventional instruments. Though several studies show the advantages of these devices, some drawbacks and unsolved problems are still present, such as the cost of the device and the large dimensions of the equipment. Purpose: In the present study, the effectiveness of dental surface ablation with a picosecond infrared diode-pumped solid-state (DPSS) laser was investigated. In vitro tests on extracted human teeth were carried out, with assessment of the ablation quality in the tooth and thermal increase inside the pulp chamber. Materials and Methods: A solid-state picosecond laser was used for the experiments. The samples were exposed to laser energy at 1064 nm at a frequency of 30 kHz and a 500 ps pulse width. The target teeth were cooled during exposures. The internal temperature of the pulp chamber was monitored with. thermocouple. Results: Optical microscope images showed effective ablation with the absence of carbonisation and micro-cracks. The cooling maintained the temperature rise in the pulp chamber below the permitted 5.5°C. Discussion: The main problem with the use of lasers in dentistry when teeth are the target is the heat generated in the pulp chamber of the target teeth. With lasers operating in the femtosecond mode, a better management of the internal temperature is possible, but is offset by the high cost of such devices. With the ps domain system used in the present study together with cooling using chilled water, effective and clean ablation could be achieved with a controlled thermal effect in the pulp chamber. Conclusions: In this preliminary study with a picosecond domain DPSS laser using water cooling for the target, effective hard tissue ablation was achieved keeping the thermal increase in the pulp within the permitted range. The results suggest that this system could be used in clinical practice with appropriate modifications.
Background and Aims: It has been reported that low-level laser irradiation (LLLI) can influence muscle tissue by retarding attenuation of muscle tension. Since the efficacy of LLLI on the effects of muscle contraction remains unclear, we examined in an in vivo animal model whether LLLI affects both muscle tension and muscle hardness in a wavelength-dependent manner, using the rat gastrocnemius muscle. Material and Methods: Forty Sprague-Dawley adult rats were used. Under pentobarbital sodium anesthesia, their gastrocnemius muscle and tibial nerve were exteriorized. Diode LLLI systems delivering 3 wavelengths (405, 532, and 808 nm; 100 mW output) were used. Ten sets of tetanus (tetanic contractions) were delivered to the tibial nerve followed by a brief rest or LLLI for 15 s and an additional 7 sets of tetanus with an inter-stimulus interval of 5 min. The muscle tension and muscle hardness were measured with a tension transducer and hardness meter, respectively. Results: 405 nm LLLI did not influence either muscle tension or hardness. 532 nm LLLI significantly improved the maintenance of muscle tension compared with the 808 nm group (P‹0.05). In contrast, 808 nm LLLI significantly improved the recovery from muscle hardness compared with the other groups (P‹0.05). Conclusion: We conclude that LLLI has wavelength-dependent effects on the gastrocnemius muscle and LLLI at appropriate wavelengths and dosimetry offers potential in the treatment to relieve muscle tension or stiffness.
Background and aims: This study was aimed at the development of a novel noninvasive treatment system, “pinpoint plantar long-wavelength infrared light irradiation (PP-LILI)”, which may be able to relieve mental stress and normalize blood glucose level via the reduction of stress hormones in type 2 (non-insulin-dependent) diabetes mellitus (DM) patients. Materials (Subjects) and methods: Based on this hypothesis, the present study was undertaken to examine effects of PP-LILI on stress hormones (ACTH and cortisol), blood glucose, HbA1c, and insulin levels in 10 patients with type 2 DM. Each patient received PP-LILI of the foot for 15 minutes once weekly using a stress free apparatus (infrared wavelength, 9,000-12,000 nm/power 30 mW). Results: In response to this therapy, ACTH (P<0.01) and cortisol (P<0.05) levels decreased significantly. Fasting blood glucose (P<0.05) and insulin (P<0.05) levels also decreased significantly along with a tendency for HbA1c to decrease. Conclusions: The present data raise the possibility that PP-LILI can normalize blood glucose levels by reducing stress hormones such as cortisol, which aggravate DM, and by improving insulin sensitivity, thereby contributing to prevention and treatment of DM.