Both increase and decrease in the dentine acid dissolution rate have been

observed in different investigations.12 and 13 Continuous CO2 laser (λ = 10.6 μm) irradiation of dentine with 1 W caused a significant decrease in calcium acid solubility in the study of Hossain et al. 14and the opposite (increase in acid dissolution) in the study of Featherstone et al. 13 using the same power and the same laser. Moreover, of the few published studies investigating the caries preventive effect of the 10.6 μm wavelength in dentine, over half of them were performed using the continuous-wave emission mode.13, 14, 15 and 16 As it is known that selleck compound continuous irradiation significantly increases the chances of thermal damage to the hard and soft dental tissues, this irradiation mode has been not recommended for clinical treatment.17 and 18 On the other hand, studies testing irradiation with the pulsed-mode presented inhibition of demineralization and increase in fluoride uptake,

but failed to report several irradiation parameters.19 and 20 Consequently, this makes it difficult to reproduce these investigations and hampers more complex, direct in situ or in vivo investigations from being conducted. Considering that pulsed irradiation decreases the risks of irreversible damage to the

dental pulp and could Sirolimus ic50 be more indicated for a future clinical trial, the purpose of the study was firstly, to investigate whether dentine irradiation with a pulsed CO2 laser (10.6 μm) emitting pulses of 10 ms is capable of influencing mineral loss in an artificial caries model. Secondly, to verify whether these irradiation conditions promote pulp chamber temperature increase within the safe range. Ninety bovine incisors that had been stored in a 0.1% thymol solution (pH 7.0) directly after extraction were used. The roots were separated from the crowns using a diamond saw under water cooling and slabs measuring 4 mm × 4 mm (2 mm thick) were obtained from their cervical thirds. The outer surface of the samples Obatoclax Mesylate (GX15-070) was serially flattened with 240-, 400- and 600-grit Al2O3 abrasive papers and polished with polishing cloths and 6 μm alumina paste. Between every polishing step the samples were submitted to a 30-s sonication bath. The samples were observed under a stereomicroscope (Nikon SMZ 1000, Nikon Corporation, Tokyo, Japan) and those presenting surface structural defects or cracks were discarded. All the slabs were completely covered with acid-resistant varnish except for a rectangular window measuring 2 mm × 4 mm on the external surface.