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This study evaluated the effect of 2.5% sodium hypochlorite (SH) or calcium hypochlorite (CH) submitted to passive ultrasonic irrigation (PUI) or conventional irrigation (CI) on the incidence of residues and the bond strength of the cementation system to post-space dentin. Distilled water (DW) and 2.5% SH followed by 17% EDTA (SH-ED) were used as negative and positive control groups, respectively. The cervical, middle, and apical thirds of the post space were evaluated. One hundred and twenty bovine incisors were endodontically treated and post-space preparation was performed. The specimens were randomly assigned to six groups, according to the solution and irrigation method: DW-CI, SH-ED-CI-SH, SH-CI, SH-PUI, CH-CI, and CH-PUI. The incidence of residues (n=10) over the dentin was evaluated by scores using SEM images. Other specimens were irrigated as previously described and the post cementation was immediately performed using a conventional dual resin cement and a two-step etch-and-rinse adhesive system. Push-out and failure modes were performed for bonding evaluation. Kruskal-Wallis and Dunn test for incidence of residues data and one-way ANOVA and Tukey tests for bond strength data were used at a significance level of 5%. The protocols that showed a lower incidence of residues were: SH-ED-CI-SH, SH-PUI, and CH-PUI for the cervical third and SH-ED-CI-SH for the middle third (p<0.05). In the apical third, the protocols were similar to each other (p>0.05). Bond strength values were higher after irrigation with DW-CI for all thirds (p<0.05). 2.5% sodium or calcium hypochlorite negatively impacted the adhesion interface and exhibited a greater incidence of residues over the post-space radicular dentin., (©Operative Dentistry, 2024.)

Aims: This study evaluated the effectiveness of different mechanical protocols using rotary brush (RB), ultrasonic tip, and oscillatory system (OS) associated with 2.5% sodium hypochlorite (NaOCl) in the removal of residues and dentin permeability in the cervical and apical segments of the post space., Settings and Design: Experimental in vitro study., Methods: Forty roots from human first molars were prepared and divided into four groups according to the cleaning protocols: Control (CO), NaOCl 2.5% conventional irrigation with a syringe; RB associated with NaOCl 2.5%; ultrasonic tip (US) associated with NaOCl 2.5%; OS associated with NaOCl 2.5%., Statistical Analysis Used: The persistence of residues was evaluated by scanning electron microscopy and data submitted to Kruskal-Wallis and Dunn tests, and dentin permeability evaluated by confocal microscopy and date submitted to ANOVA one-way and Tukey's tests ( P = 0.05)., Results: There were no differences in residue cleaning among the CO, RB, US, and OS groups, regardless of the analyzed root segment ( P > 0.05). When comparing groups, dentin permeability in the CO group was significantly lower in the cervical segment ( P < 0.05)., Conclusions: The OS group promoted the highest permeability value in the apical segment. RB, US, and OS are similar in removing residues from the post space. However, OS results in higher dentin permeability in the apical segment., Competing Interests: There are no conflicts of interest., (Copyright: © 2024 Journal of Conservative Dentistry and Endodontics.)

Objective: To evaluate in vitro the effect of dental bleaching using high concentration hydrogen peroxide (HP) photoactivated with violet LED on fracture strength and hybrid layer formation., Methods: forty endodontically-treated bovine teeth were randomized into four groups (n = 10): C - Control, HP - 35% hydrogen peroxide, HP-BL - 35% hydrogen peroxide photoactivated with blue LED, HP-VL - 35% hydrogen peroxide photoactivated with violet LED. Three bleaching sessions with an interval of 7 days between them were performed. After 10 days of the last bleaching session, the dental crowns were restored and submitted to the fracture strength test. Five specimens from each group were used to evaluate the hybrid layer formation by scanning electron microscope (SEM) images. One-way ANOVA and Kruskal-Wallis test were used for parametric and non-parametric data, respectively. Significance level of 5% was adopted to all the tests., Results: No differences on fracture strength among the groups were observed (p > 0.05). HP and HP-BL showed alterations on hybrid layer formation compared to C group (p < 0.05), but not for HP-VL (p > 0.05). No differences on hybrid layer formation were observed among HP, HP-VL and HP-BL groups (p > 0.05)., Conclusion: Dental bleaching, photoactivated or not, did not affect the fracture strength of endodontically-treated teeth. Regardless of the protocol used, hydrogen peroxide altered the hybrid layer formation at some level when the restoration was placed after 10 days of the last bleaching session., Competing Interests: Declaration of Competing Interest The authors declare no any conflict of interest in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background: To evaluate the efficacy of dental bleaching protocols using 35% hydrogen peroxide photoactivated with violet LED on color and microhardness of endodontically treated teeth., Methods: Forty specimens were selected and randomized into 4 groups (n = 10): C - Control, HP - 35% hydrogen peroxide, HP + BL - 35% hydrogen peroxide + blue LED, HP + VL - 35% hydrogen peroxide + violet LED. Three bleaching sessions were performed for each group. Color analysis was performed 7 days after each bleaching session. Two-way repeated measure ANOVA and Bonferroni test were used to evaluate the effect of different bleaching protocols and evaluation times on the dependent variables (∆E and ∆L). Dentin microhardness was measured 24 h after the third bleaching session. Data were evaluated by ANOVA and Tukey's test at a significance level of 5%., Results: Differences on ∆E and ∆L were verified after the first and second bleaching sessions (p < 0.05) and showed stability after the third one, for all the groups. No differences were observed among HP, HP + BL, and HP + VL groups, regardless of the evaluation time (p > 0.05). HP and C showed the greatest and smallest reduction in dentin microhardness (p < 0.05), respectively. No difference between HP + BL and HP + VL protocols (P > 0.05) was observed., Conclusions: High concentration hydrogen peroxide (35%) photoactivated with violet LED bleached endodontically treated teeth effectively. However, the same protocol negatively affected the dentin microhardness, but not in the same level of 35% HP solely used., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest in this paper, (Copyright © 2023. Published by Elsevier B.V.)

Background: Few studies have investigated the effect of violet LED irradiation associated or not with bleaching agents on blood-stained teeth. This in vitro study aimed to evaluate the whitening efficacy and color stability of non-vital dental bleaching using 35% hydrogen peroxide (HP) photoactivated with violet LED (VL) compared to 35% HP alone and 35% HP photoactivated with blue LED (BL)., Methods: Fifty bovine dental crowns were used to obtain specimens of 5 × 5 × 2 mm. After selection based on a previous colorimetric analysis, the specimens were blood-stained and randomly assigned into five groups (n = 10): control (no treatment); 35% HP, 35% HP/BL; 35% HP/VL; and VL. Three bleaching sessions were performed and the colorimetric analysis (∆E ab, ∆L, and ∆WI D ) was recorded after 7 days, 30 days, and 9 months of the last bleaching session. Two-way repeated measures ANOVA followed by Bonferroni post-hoc test was used at a significance level of 5%., Results: 35% HP, 35% HP/BL, and 35% HP/VL showed higher values of ∆E ab, ∆L, e ∆WI D (P < 0.05), without intra- and intergroup differences (P > 0.05). C and VL were similar in all the evaluation times (P > 0.05), showing lower values of ∆E ab, ∆L, and ∆WI D (P < 0.05)., Conclusions: 35% HP/VL can be a viable alternative for dental bleaching in endodontically-treated teeth, showing bleaching efficacy similar to 35% HP solely used, even after a 9-month follow-up. VL used alone was not effective to bleach blood-stained teeth., Competing Interests: Declaration of Competing Interest The authors declare no any conflict of interest in this paper, (Copyright © 2023 Elsevier B.V. All rights reserved.)

Aim: This study aimed to evaluate the effect of a laser-activated bleaching agent containing titanium dioxide (TiO 2 ) nanoparticles on enamel roughness and hardness., Materials and Methods: Twenty human premolars were randomized into two groups according to the bleaching treatments performed: HP - 35% hydrogen peroxide and HP + TiO 2 - 30% hydrogen peroxide containing TiO 2 light-activated by diode laser (980 nm). It was performed two bleaching sessions with an interval of 7 days. Microhardness and roughness of the enamel were assessed at three times: T0 - Before 1 st appointment, T1 - after 2 nd appointment, and T2-7 days after 2 nd appointment., Results: The HP + TiO 2 did not cause changes on enamel roughness and hardness and presented the same effects of the HP., Conclusions: Both bleaching agents showed no difference between them. Then, it is possible to conclude that both are viable for clinical use during in-office dental bleaching technique regarding the microstructural changes that they might cause., Competing Interests: There are no conflicts of interest., (Copyright: © 2021 Journal of Conservative Dentistry.)

Different light sources have been used during dental bleaching procedures. More recently, a violet LED system was introduced as a promising and viable light source, which is capable to promote dental bleaching without chemical agents, although this light source could be also associated to a bleaching agent. This case report aimed to present the association of a violet LED and a bleaching agent over a discolored non-vital tooth. After anamnesis, clinical and radiographic examinations, a dental bleaching protocol was proposed as follow: 15 applications of the violet LED during 60 s (Bright Max Whitening, MMOptics) with 30 s interval between them. Before the last 5 applications, 35% hydrogen peroxide gel (Whiteness HP Maxx, FGM) was applied inside the pulp chamber and on enamel surface of the tooth (vestibular and palatal surfaces) and then the last 5 irradiations were performed. Three sessions were performed, with 7-days interval. Color assessment using a VITA classical scale and VITA EasyShade® spectrophotometer was carried out. After dental bleaching, color changed (tooth 21) from A3.5 to B2. The protocol used in this case report showed to be satisfactory for the non-vital tooth bleaching., (Copyright © 2019. Published by Elsevier B.V.)