Purpose:The aim of this study was to compare the effect of Nd:YAG laser to that of a new varnish: MI Varnish with RECALDENT (GC), for the treatment of dentin hypersensitivity, with a follow-up of 6 months. Dentinal hypersensitivity was evaluated using a new thermal test never before used on dental tissue. Materials and Methods: A split-mouth design was used where teeth on one side received the same type of treatment. Twelve patients suffering from dentin hypersensitivity were chosen. Fifty-four teeth were divided into 27 pairs. Twenty-seven teeth received the Nd:YAG laser treatment, and the 27 contralateral teeth received MI Varnish application. Five parameters were measured, and the measurements were taken before treatment at baseline (T0), after 1 week (T1), 1 month (T2), 3 months (T3), and 6 months (T4) of the application. Air stimulation to obtain the Schiff air score, the score of discomfort according to the visual analog scale (VAS), the tactile score, and the thermal test that determines the minimum cold-stimulating temperature and the maximum heat-stimulating temperature were all used to assess sensitivity. Statistical analyses of the data were performed, and the significance level was set at p ࣘ 0.05. Exact Fisher tests and Chi-Square tests were conducted to compare percentages. Results: There was a clear decrease in dentin hypersensitivity for both treatments (Nd:YAG laser and MI Varnish) especially between baseline and 1 week, with maintenance of this state through the 6-month follow-up period. The difference between the two treatments was not significant, comparing, over time, the Schiff air score, the thermal test, and the VAS; however, the tactile score was significantly improved 6 months after the application of MI Varnish compared to the laser (p = 0.05). Conclusion: There was no significant difference between the two treatments, Nd:YAG laser and MI Varnish. Both treatments were effective and reduced dentin hypersensitivity immediately after treatment up to 6 months.

Objective. To investigate the shear bond strength of self-adhering flowable resin composite, to dentin, after exposing it to Er:YAG laser radiation, at different energy densities. Materials and Methods. Sixty freshly extracted human third molars were randomly divided into five groups (n = 12). In the control group, dentin was left unirradiated, whereas, in the other four groups, dentin was irradiated with Er:YAG laser in noncontact mode (MSP mode = 100 µs; 10 Hz; beam diameter: 1.3 mm; speed of 1 mm/second; air 6 mL/min; and water 4 mL/min), and respectively, with the following level of energy (50 mJ, 60 mJ, 80 mJ, and 100 mJ). Then, self-adhering flowable resin composite was bonded to all prepared dentin surfaces. Shear bond strength (SBS) was applied and fractured surfaces were examined using scanning electron microscopy. Results. SBS values showed significant differences in 60 mJ (P < 0.05) compared to other groups. Morphological evaluation revealed tags or plugs in dentinal tubules, especially when 60 mJ and 80 mJ were used. All four groups tended to leave more residues on the dentin surface, than the control group. Conclusion. Er:YAG dentin irradiation may enhance SBS of the self-adhering flowable resin composite when it is used at the appropriate low level of energy density.

Direct pulp capping induces a local inflammatory process. Several biomaterials have been used for this procedure. The aim of this study was to compare the dentinal bridge thickness using three different pulp capping biomaterials with the conventional technique (high speed diamond bur) or Er-Yag laser, 1 month after pulp effraction. Materials and Methods: Forty two Class V cavities were prepared on the buccal surface of 4 maxillary incisors and 2 mandibular incisors of New Zealand rabbits. Specimens were divided into 6 treatment groups. Teeth were treated with: In Group 1: Er-Yag laser and Biodentine® (Septodont), in Group 2: Er: Yag laser and calcium hydroxide (Dycal® Dentsply), in Group 3: Er: Yag laser and adhesive system (Prime& Bond® NT Dentsply), in Group 4: high speed diamond bur and Biodentine® (Septodont), in Group 5: high speed diamond bur and calcium hydroxide (Dycal® Dentsply), and in Group 6: high speed diamond bur and adhesive system (Prime& Bond® NT Dentsply). The preparation was done with copious irrigation. The animals were sacrificed at 30 days and the teeth were extracted and prepared for histological analysis. Results: In the group of « laser Er-Yag », iatrogenic pulpal wounds treated with Biodentine® were covered with a thick hard tissue barrier after 1 month. The difference was not significant with the groups of Dycal® used with Er: Yag laser and high speed diamond bur. Prime& Bond® NT Dentsply specimens showed a thin dentinal bridge layer. Conclusion: At 1 month, Er-Yag laser proved to be useful with Biodentine® for direct pulp capping procedures.

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