Microleakage in Class V cavities with self-etching adhesive system and conventional rotatory or laser Er,Cr:YSGG.

OBJECTIVE: To analyse microleakage in Class V cavity preparation with Er;Cr:YSGG at different parameters using a self-etching adhesive system. BACKGROUND: Several studies reported microleakage around composite restorations when cavity preparation is done or treated by Er;Cr:YSGG laser. We want to compare different energy densities in order to obtain the best parameters, when using a self-etching adhesive system. METHODS: A class V preparations was performed in 120 samples of human teeth were divided in 3 groups: (1) Preparation using the burr. (2) Er;Cr:YSGG laser preparation with high energy 4W, 30 Hz, 50% Water 50% Air and (3) Er;Cr:YSGG laser preparation lower energy 1.5 W, 30 Hz, 30% Water 30% Air. All the samples were restored with self-etching adhesive system and hybrid composite. Thermocycling (5000 cycles) and immersed in 0.5% fuchsin. The restorations were sectioned and evaluated the microleakage with a stereomicroscope. RESULTS: Lower energy laser used for preparation showed significant differences in enamel and dentin. To group 3, the microleakage in the enamel was less, whilst the group 1, treated with the turbine, showed less microleakage at dentin level. Group 2 showed the highest microleakage at dentin/cement level. CONCLUSION: Burr preparation gives the lowest microleakage at cement/dentin level, whilst Er;Cr:YSGG laser at lower power has the low energy obtains lowest microleakage at enamel. On the contrary high-energy settings produce inferior results in terms of microleakage.

Patients' answers to a postoperative questionnaire related to laser resurfacing.

To date there is no information that evaluates, from the patient's point of view, the experience of undergoing CO(2) laser skin resurfacing. This article investigates the outcome of laser resurfacing for various cutaneous problems with respect to the patient's expectations and experiences and the surgeon's opinions. Patients were entered into the study prospectively and presented with a questionnaire, at 12 months after treatment, to evaluate the patient's skin resurfacing experience. All patients received standardized preoperative counseling and underwent a standardized surgical protocol, conducted by the same surgeon. Eighty-eight percent of patients considered the result of the laser resurfacing to be very good, and 97% indicated that they had experienced little pain or discomfort. Nevertheless, 77% of patients stated that they would be unwilling to undergo another resurfacing procedure. This discrepancy is most likely the result of the patients' experiences in relation to the degree of erythema afterward. Most patients stated a desire to have more information regarding the procedure, particularly with respect to their experiences concerning postoperative erythema and exudates in the treated area. From the study it can be concluded that patients require extensive preoperative counseling, including a full explanation of all possible sequelae of these procedures to improve the patient's experience.

Possible mechanisms for an irregular vessel coagulation when long laser pulses are used in the treatment of port-wine stains.

The laser treatment of port-wine stains (PWS) has as a main aim the irreversible damage of ectatic vessels. Blood content of the subcutaneous venous plexus in PWS can be increased by a factor of seven or more, compared to that of the normal skin. The venous blood velocity ranges from 0.1-1 mm/s in capillaries to approximately 22 mm/s in larger vessels of about 300 microns in diameter. A PWS, selected for study, was irradiated with a multiline argon laser 488/515 nm wavelength, 1.5 W power, 200 ms pulse duration, 0.5 mm beam diameter and repetition frequency up to 5 Hz. Laser shots were placed adjacently in an area of 1 cm2. Using these parameters, in the case of dilated PWS vessels with an optical penetration depth and thermal diffusion length less than the diameter of the vessel, together with a transit time of blood across the irradiated spot less than the pulse duration, and estimating that during a pulsed laser emission of 200 ms, the blood has travelled a distance of 3-4 mm, there is a strong indication that hemodynamics during irradiation may influence the pattern of coagulation and agglutination. Thrombosis should occur in the case of small vessels and, in larger vessels, the coagulated blood will only partly fill the lumen. The structure developed in the vessel interior may also change continuously with time, as the coagulated material is progressively replaced by fibrotic tissue and the irregular agglutination pattern may be due to inhomogeneity in the absorbed optical energy.

Improving the results of facial dermal lesions elimination by laser.

Argon laser therapy of superficial pigmented lesions in both young and old people is associated with a risk of complications including delayed wound closure and hypo/hypertrophic scarring. Problems may also occur after treatment of lesions located on the eyelid. To minimize the risk of these problems coagulation of deep tissue should be avoided. We discuss a technique using mercurochrome, a red-colored compound that absorbs the blue and green lines of the argon laser, as a barrier for the irradiated light that eliminates these complications and we provide probable reasons for this technique's effectiveness.