Aim and objective To compare the effectiveness of erbium:yttrium–aluminum–garnet laser, GentleWave irradiation, photodynamic therapy (PDT), and sodium hypochlorite in smear layer removal and dentin permeability with a scanning electron microscope (SEM). Materials and methods Seventy-five recently extracted single-rooted teeth (maxillary second premolars) were randomly divided into 5 groups of 15 each. Group I teeth was the control group in which conventional root canal preparation (RCP) [17% ethylenediaminetetraacetic acid (EDTA)] was done without laser irradiation, group II teeth underwent RCP and GentleWave™ treatment, group III teeth were subjected to Er:YAG laser irradiation, group IV uses low-level 660 nm (PDT), and group V samples were irrigated with 5.25% NaOCl. All samples were viewed under the SEM. Images at the coronal, middle, and apical part of the root canal were obtained at ×1000. A scoring system for smear layer removal and debris removal scoring was used for analysis. Results Smear layer removal was significantly higher at different points (coronal, middle, and apical area) in group I, followed by V, IV, II, and group III in declining order (p < 0.05). Intercomparison between the groups at different points indicates a significant difference in smear layer removal score between group I and group V at coronal, middle, and apical third. The result was not significant at coronal third and middle third, between group I and V, II and III, II and IV. The result was not significant at apical third between I and V, II and III, and II and IV (p < 0.05). Ethylenediaminetetraacetic acid and sodium hypochlorite are effective in smear layer removal followed by the Er-YAG laser technique. Conclusion Ethylenediaminetetraacetic acid and NaOCl are effective in smear layer removal. Er:YAG laser-activated RCP was comparatively efficient in cleaning the smear layer and opening dentinal tubules. Clinical significance Er:YAG laser-activated RCP was comparatively efficient in cleaning the smear layer and it can be used for effective removal of smear layer for clinical usage. How to cite this article Dash S, Ismail PMS, Singh J, et al. Assessment of Effectiveness of Erbium:Yttrium–Aluminum–Garnet Laser, GentleWave Irradiation, Photodynamic Therapy, and Sodium Hypochlorite in Smear Layer Removal. J Contemp Dent Pract 2020;21(11):1266–1269.

The purpose of the study was to compare two different commercial bleaching agents, Opalescence with Colgate Platinum, and 30% phosphoric acid used as aggressive agent on the morphology of human enamel. Materials and methods:Ten freshly extracted, noncarious, human maxillary central incisors extracted for periodontal reasons were used in this study. The labial surface of the disinfected teeth were polished using a polishing paste with the help of rubber cup and a slow speed handpiece. Each tooth was sectioned at cement-enamel junction and the crown was separated into four specimens, all taken from labial surface. Group 1 was treated with Colgate Platinum for 7 hours, group 2 with Opalescence for 7 hours, group 3 was treated with 30% phosphoric acid for 30 seconds and group 4 was untreated and used as control. After the treatment period, the specimens were washed with normal saline and stored in sterile bottle and sealed. Photomicrographs obtained from the scanning electron microscopy (SEM) after surface treatments were examined for no alteration, slight alteration, moderate alteration and severe alterations. Results:The specimens treated with commercial bleaching agents revealed no enamel surface morphologic alterations compared to control group. The specimen treated with phosphoric acid showed severe alterations. Conclusion:Ten percent carbamide peroxide evaluated in this study does not etch tooth enamel or alter enamel surface morphology as do conventional etching techniques.Clinical relevance: Carbamine peroxide is a safe and effective tooth whitening agent even when used for extended period of time. The enamel surface remains smooth which reduces caries due to plaque collection.

The study aims to evaluate and compare the onset of local anesthesia (LA) and pain perception during endodontic treatment in hemophilic and thalassemic patients. Methods: The study included 90 patients with symptomatic irreversible pulpitis of the mandibular molars. Three groups (n = 30 in each group) were included. Group 1: hemophilic patients; group 2: thalassemic patients; and group 3: individuals without any systemic diseases. Onset of LA and visual analogue scale (VAS) scores was recorded immediately after the administration of local anesthesia, during the pulp exposure procedure, and during canal instrumentation, and were compared between the three groups. Frequency distribution, ANOVA, and linear regression analysis (p < 0.05) were applied. Results: The mean onset time was 46 ± 34 s in the hemophilic group, 42 ± 23 s in the thalassemic group, and 38 ± 12 s in controls, but the differences were statistically insignificant. After LA administration (LA-VAS), all three groups experienced a statistically significant reduction in pain (p = 0.048). On pulp exposure (PE-VAS) (p = 0.82) and during canal instrumentation (CI-VAS) (p = 0.55), there was no statistically significant difference in pain perception between the groups. The coefficients indicate a positive correlation between the VAS and onset time, indicating a positive reduction in the VAS following the administration of LA. Conclusions: Hemophilic patients exhibited a clinically longer average onset time for LA. However, the difference among the three groups with regard to the overall pain perception after LA administration, during and after pulp exposure, and during canal instrumentation was statistically insignificant.

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