Search

Puapichartdumrong P, Ikeda H, Suda H.Influence of the pulpal components on human dentine permeabilityin vitro.International Endodontic Journal,38, 152–159, 2005.To examine the influence of the retained pulpal components on permeability of human dentine by monitoring drug diffusion.Twelve intact dentine discs were prepared from freshly extracted human third molars. The dentine surface on the enamel side was etched with 10% polyacrylic acid for 30 s. The drug diffusion test was carried out before and after removal of the retained pulpal components. Each dentine disc was inserted between two plastic chambers; enamel- and pulpal-side chambers, which were filled with 0.05 mol L−1 naproxen sodium (NA) and phosphate-buffered saline (PBS), respectively. After 10 min, the solution on the pulpal-side chamber was collected to determine the concentration of NA using a spectrophotometer. To remove the retained pulpal components and residual NA, the pulp chamber of each disc was washed out with PBS and placed in an ultrasonic cleaner. After removal of these components and the residual NA, the drug diffusion test was repeated. The inner surface of the pulp chamber was observed using scanning electron microscopy (SEM) before and after the removal of the retained pulpal components.The amount of NA that diffused through dentine into the pulp was significantly higher after the pulp chamber was washed out with PBS (pairedt-test,P < 0.05). SEM observation demonstrated the presence of the retained pulpal components, odontoblastic layer and some parts of subodontoblastic zone, covering the surface of predentine. These components were removed after the pulp chamber was washed out with PBS followed by cleaning in an ultrasonic cleaner.The presence of retained pulpal components had a significant influence on drug diffusion through dentine discs. [ABSTRACT FROM AUTHOR]

Previous in vitro permeability and scanning electron microscopic (SEM) studies have demonstrated the effectiveness of the oxalate ion in dentine permeability reduction and effective tubule occlusion. The aim of this randomized double-blind, split mouth 4-week clinical study, therefore was to determine whether a 1-min application of ferric oxalate (Sensodyne Sealant) on exposed root dentine was effective in reducing dentine hypersensitivity (DH). Thirteen subjects [8F:5M, mean age 46·2 (s.d. 4·15) years] completed the study. The subjective response was evaluated by tactile, thermal and evaporative methods of assessment. Data were collected at baseline and post-application at +5 min and 4 weeks. Analysis was based on paired t-test ( P=0·05) and Wilcoxon–Mann–Whitney tests. No statistically significant differences were noted between ferric oxalate and placebo preparations at +5 min and 4 weeks for any of the test stimuli. There was, however, a clear trend towards immediate reduction (+5 min) in DH reverting back to baseline values at 4 weeks with the exception of the Biomat Thermal Probe mean values, which maintained the reductions in DH compared with placebo. The results of the present study demonstrated that a 1-min application of ferric oxalate is both rapid and effective in reducing DH although its long-term effectiveness still needs to be determined. [ABSTRACT FROM AUTHOR]

Bacterial invasion of dentinal tubules is a critical step in the pathogenesis of dental caries and pulp and periapical disease. The purpose of this study was to determine the effect some molecules commonly found in saliva and dentinal tubule fluid may have on the bacterial invasion of dentine. The results showed that invasion of Streptococcus gordonii or Enterococcus faecalis cells was inhibited when the bacterial cells were in solution with mucin, immunoglobulin G (IgG) and serum, and this was related to bacterial cell aggregation, as a result of interaction with agglutinins, and/or inhibition of collagen binding. When dentine was soaked in growth media containing fibrinogen, IgG, albumin or serum prior to inoculation, bacterial invasion was inhibited. It is suggested that this may be due to reduced dentine permeability as a consequence of the deposition of the compounds within dentinal tubules. [ABSTRACT FROM AUTHOR]

This study evaluated the effect of different concentrations of alpha‐tocopherol in gel form on fracture strength, hybrid layer formation, and microtensile bond strength of endodontically treated teeth bleached with 40% hydrogen peroxide (H2O2). Sixty bovine incisors were randomized into one of six groups (n = 10 incisors per group) defined by the interventions carried out after endodontic treatment. In the control group, no additional intervention was carried out, while all teeth in the five intervention groups were bleached with 40% H2O2 and subsequently treated with alpha‐tocopherol at concentrations of 15% (15AT), 20% (20AT), or 25% (25AT), with 10% sodium ascorbate (10SA), or with nothing (40HP). Fracture strength was evaluated in a mechanical testing machine, hybrid layer formation was assessed using scanning electron microscopy, and bond strength was determined using microtensile bond‐strength testing. Data were analyzed using Kruskal–Wallis and Dunn's tests. No statistically significant difference regarding fracture strength was observed among groups. Hybrid layer formation was greater in the 15AT group than in groups 40HP and 10SA. Teeth in groups 15AT, 20AT, and 25AT demonstrated higher bond strength than teeth in groups 40HP and 10SA. Alpha‐tocopherol, preferably at 15%, effectively reverses the deleterious effects, of bleaching, on hybrid layer formation and bond strength to dentin. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of storage time on the dislocation resistance of core material to root canal sealer in standardized artificial root canals. Methods: A single root canal with a round shape was selected using cone-beam computed tomography imaging, and root canal treatment was performed. The root was scanned with micro-computed tomography, and the data were exported as a stereolithography file. Forty artificial roots were manufactured using 3D printing technology. The artificial root canals were obturated using a single cone technique. The roots were divided into two groups according to the storage time of filled roots: 7 days and 30 days (n = 20), and stored at 37°C and 100% humidity. After each storage period, 2-mm sections were taken from the middle part of the roots. The sections were tested on a universal testing machine. The dislocation resistances (MPa) were calculated, and the data were analyzed using the Shapiro-Wilk test and independent samples t-test (α = .05). Results: The dislocation resistance of the filling material was significantly higher in the 30-day storage time group compared to the 7-day group (p < .05). Conclusion: The storage time of the root fillings affected the dislocation resistance in the standardized experimental setup with artificial roots. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to identify the 100 top-cited articles on dentin adhesives utilizing comprehensive bibliometric and altmetric analyses. Materials and methods: The Institute of Scientific Information Web of Knowledge database was used to compile the top-cited articles published from 1945 through February 12, 2023. Citation counts were manually retrieved for each article from Scopus, Google Scholar, Dimensions, and Altmetric. The articles were analyzed in terms of their number of citations, year, journal name, author (name, institution, and country), and type and specific field of study. We used descriptive statistics to summarize the results. Results: The analysis revealed that the top 100 cited articles originated from 18 English-language journals and collectively accumulated a remarkable 34526 citations. The article with the highest number of citations garnered 1288 references. Among authors, Van Meerbeek B. stood out with nine articles and 4650 citations, followed by Pashley D.H. with six articles and 2769 citations. Japan was the leading contributor by country, while the Catholic University of Leuven led in terms of institutions with 20 articles. Conclusion: According to this study, basic research and review articles garnered the most citations, respectively. The citation analysis revealed different trends for researchers, the first being that researchers have focused on basic fields such as the ultramorphology of dentin and adhesive interfaces, followed by bond strength to dentin. Two studies on clinical experiences suggested that studies with high-level evidence, such as systematic reviews, meta-analyses, or randomized controlled clinical trials, are required. Clinical relevance: It is identified that more studies with high-level evidence-based research are needed in the field of dental adhesives. [ABSTRACT FROM AUTHOR]

This review explores the transformative role of nanoparticles in modern dentistry, specifically within conservative dental procedures and endodontics. It delves into the diverse applications of nanomaterials, highlighting their enhanced properties in diagnostics, therapeutic agents, and restorative materials. The article discusses recent advancements in nanoparticle-based techniques, emphasizing their potential for improving treatment outcomes, minimizing invasive procedures, and addressing challenges in dental care. By presenting a comprehensive overview of nano-enabled innovations, this review aims to underscore the significance of these tiny yet powerful elements in reshaping the landscape of conservative dentistry and endodontics. [ABSTRACT FROM AUTHOR]

Plasma, the fourth fundamental state of matter, comprises charged species and electrons, and it is a fascinating medium that is spread over the entire visible universe. In addition to that, plasma can be generated artificially under appropriate laboratory techniques. Artificially generated thermal or hot plasma has applications in heavy and electronic industries; however, the non-thermal (cold atmospheric or low temperature) plasma finds its applications mainly in biomedicals and therapeutics. One of the important characteristics of LTP is that the constituent particles in the plasma stream can often maintain an overall temperature of nearly room temperature, even though the thermal parameters of the free electrons go up to 1 to 10 keV. The presence of reactive chemical species at ambient temperature and atmospheric pressure makes LTP a bio-tolerant tool in biomedical applications with many advantages over conventional techniques. This review presents some of the important biomedical applications of cold-atmospheric plasma (CAP) or low-temperature plasma (LTP) in modern medicine, showcasing its effect in antimicrobial therapy, cancer treatment, drug/gene delivery, tissue engineering, implant modifications, interaction with biomolecules, etc., and overviews some present challenges in the field of plasma medicine. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate dentin chemical and ultrastructural changes upon exposure to remineralizing dentifrices. Dentin disks were obtained from permanent human molars and treated for 7 days with the dentifrices: (1) C group—control (no dentifrice); (2) S group—Sensodyne Repair & Protect; (3) D group—Dentalclean Daily Regenerating Gel; and (4) DB group—D group + Dentalclean regenerating booster. Afterwards, samples were submitted to an additional 7 days of toothbrushing associated with daily acidic challenge. Samples were imaged and analyzed (days 1, 7, and 14) for Young's modulus by atomic force microscopy (AFM), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). SEM and AFM revealed precipitate deposition on dentin surfaces in groups S, D, and DB, formed as early as day 1. Surface elemental analysis showed a Si increase on all brushed surfaces. Similar surface morphology was maintained after the acidic challenge period. Bright-field TEM/SAED revealed the formation of nanocrystalline hydroxyapatite inside the dentin tubules of groups S, D, and DB after day 7. Group C presented a gradual reduction of Young's modulus from days-1–14, whereas all remaining groups had increased values. All evaluated dentifrices led to successful formation of hydroxyapatite and increased dentin stiffness. [ABSTRACT FROM AUTHOR]

Elimination of microbes in the root canal system is crucial for achieving long-term success in endodontic treatment. Further efforts in study design and standardization are needed in order to improve the validity and comparability of in vitro results on endodontic disinfection procedures, in turn improving clinical outcomes. This study optimizes two models at all steps: tooth selection, pretreatment, inoculation method (by growth or centrifugation), and confocal laser scanning microscopy (CLSM)-guided imaging of LIVE/DEAD-stained specimens. Individual anatomical conditions lead to substantial differences in penetration depth. Sclerosis grading (SCG), a classification system introduced in this study, provides information about the sclerosis status of the dentine and is helpful for careful, specific, and comparable tooth selection in in vitro studies. Sonically activated EDTA for the pretreatment of roots, inoculation of Enterococcus faecalis in an overflow model, 3–4 weeks of incubation, as well as polishing of dentine slices before staining, led to advances in the visualization of bacterial penetration and irrigation depths. In contrast, NaOCl pretreatment negatively affected performance reproducibility and should be avoided in any pretreatment. Nonsclerotized teeth (SCG0) can be used for microbial semilunar-shaped inoculation by centrifugation as a "quick-and-dirty" model for initial orientation. In conclusion, CLSM-guided imaging for quantifying endodontic infection/disinfection is a very powerful method after the fine-tuning of materials and methods. [ABSTRACT FROM AUTHOR]

Background: Once bioceramic sealer (BCS) enters the dentinal tubules, it cannot be reliably removed. BCS-occupied dentinal tubules reduce fibre post retention strength. Coating gutta-percha with BCS only on the apical portion may improve post retention strength due to increased retention strength between the dentin and resin cement interface. The aim of the study was to test this hypothesis. Methods: Root canals of 27 extracted human mandibular premolars were instrumented and randomly assigned to three obturation methods: conventional coating (CC), non-coating (NC), and apical coating (AC). The root canals were obturated with gutta-percha to 4 mm from the working length under an operating microscope. After the BCS was completely set, post spaces were prepared, and quartz fibre posts were cemented. The apical 4.5 mm of the roots were removed. Two samples were prepared at the apical, middle, and coronal root levels (one for scanning electron microscope (SEM) study and another for the push out bond strength (PBS) test). After the PBS test, the samples were examined with a stereo microscope to determine the failure mode: dentine-cement (DC), post-cement (PC) and mixed. The PBS data were analysed by One way ANOVA for the specific obturation method effects. Repeated ANOVA was used for the specific effects of the root levels on PBS in different obturation methods. Results: At all three root levels, more continuous hybrid layers and denser resin tags were found in the NC and AC than the CC group. The AC and NC groups' PBS was significantly higher than the CC group at the apical 1/3 (p = 0.002 and p = 0.001) and coronal 1/3 (p = 0.016 and p = 0.041). The PBS in the CC group at the middle 1/3 was significantly higher than the apical 1/3 (p = 0.022). DC failure mode was most commonly found in the CC group, while PC failure mode was found most frequently in the NC and AC groups. Conclusions: The apical coating obturation method significantly increased PBS over the conventional coating method, potentially reducing fiber post dislodgement. However, this study was only preliminary. Clinical studies are required to confirm the results. [ABSTRACT FROM AUTHOR]

The article presents the author's comments on whether the use of laser can be recommended for endodontic treatment. The author says that effective use of laser energy to tackle endodontic problems still remains unfulfilled. The idea of reducing dentine permeability is based on the ability of lasers to melt dentinal tubules. However, it has not been supported by careful research.

Copyright of Arquivos de Ciências da Saúde da UNIPAR is the property of Associacao Paranaense de Ensino e Cultura and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Different kinds of interactions between the restorative material and mineralized dental tissues result in secondary caries around dental composites. Of these, the mechanical interactions have to be carefully investigated. Due to the elastic mismatch between dental tissues and the composite restoration, complex stresses and strains develop at their interface. This complex mechanical environment disturbs the demineralization-remineralization equilibrium of dental hard tissues. The fluid flow both over and within enamel and dentin, associated with their complex ultrastructure and mechanical behavior, is a key factor. It is known that external mechanical loading can indirectly promote the dissolution of enamel and dentin through a pumping action of cariogenic fluids in and out of microgaps at the interface between mineralized tissues and composite. Mechanical loading can also directly influence the physicochemical behavior of dental hard tissues by inducing complex strain and stress fields on the crystal scale. It is important to consider both the direct and indirect paths by which mechanical loading can influence the apatite dissolution kinetics. Therefore, a systematic approach should be used to investigate the mechanism of secondary caries formation considering the tooth-composite interface as a unique complex in which each element has an influence on the other. [ABSTRACT FROM AUTHOR]

Objective: This five-phase, single-blind, crossover in situ trial evaluated the effects of desensitizing or anti-erosive toothpastes on dentin erosive wear and tubule occlusion., Materials and Methods: Some characteristics such as relative dentin abrasivity (RDA), viscosity (V), cytotoxicity, and fluoride and calcium (Ca) availability of the toothpastes were also tested. Samples were positioned on removable intraoral appliances from 15 volunteers (n=4), according to the groups, C-control (0 ppm fluoride), F-sodium monofluorophosphate (MFP), A-MFP and arginine+calcium carbonate, CSP-calcium sodium phosphosilicate, and CS-MFP and calcium silicate+sodium phosphate. Erosion-abrasion cycling was performed (1% citric acid, 2min, 6×/day; toothbrushing, 5s, 2×/day). Surface loss (SL) was evaluated by optical profilometry. Environmental scanning electron microscopy images (ESEM) counted the number of open dentin tubules (ODTs). Data were statistically analyzed (α=0.05)., Results: There were no significant differences in SL among groups (p=0.468). The ODT for CSP, CS, and A groups were significantly lower than the control. CSP and CS presented significantly less ODT than F, but they did not significantly differ from A. F and CS were more abrasive than all the other toothpastes; CSP was more abrasive than A, and C was the least abrasive. CSP presented higher V (p<0.05). All toothpastes presented lower cell viability than the control without toothpaste exposure. F and A presented significantly higher values of F - (p<0.05). All fluoride toothpastes had similar amount of Ca, differing from the control (p<0.05)., Conclusion: Although the toothpastes caused similar degree of erosive wear, CSP and CS were able to occlude the dentin tubules., Clinical Relevance: Desensitizing toothpastes containing calcium, sodium, phosphate, and silicate could be a suitable option for treating dentin hypersensitivity., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Aim: This in vitro study compared the effect of two commercially available silver diamine fluoride (SDF) products on dentinal tubule (DT) occlusion and dentin permeability., Methods: Sixty-six dentin discs (1.0 mm thick) were divided equally into six groups: acid-etched with no treatment (negative control-NC), etched and sealed with nail varnish (positive control-PC), non-etched and treated with Advantage Arrest (AA), non-etched and treated with Topamine (TP), etched and treated with AA, and etched and treated with TP. Eight specimens from each group were tested for permeability using the dye percolation method. The remaining three samples from each group were assessed for dentinal tubule occlusion, depth of SDF penetration, and elemental analysis using a scanning electron microscope coupled with an energy-dispersive X-ray (SEM/EDX) system. One-way ANOVA and Tukey's post hoc test were used to analyze the results., Results: TP exhibited lower (p < 0.05) dye percolation compared to AA. While both SDF materials showed a statistically similar (p > 0.05) penetration depth in the DT, none of them had the ability to completely occlude all the DTs. AA exhibited more silver and fluoride ion deposition on etched dentin than TP, and both materials showed a similar increase in the deposition of Ca and P compared to NC., Conclusions: Whereas the effectiveness of dentin tubule (DT) occlusion varies based on the material used, both tested SDF products exhibit the capability to seal dentinal tubules, decrease dentin permeability, and promote dentin remineralization. These findings suggest their potential advantage in managing dentin hypersensitivity., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objective: To evaluate the influence of air-abrasion of enamel with three different desensitizing powders on the whitening effect of a bleaching gel containing 40% H 2 O 2 , which was used for in-office tooth bleaching., Materials and Methods: Forty human incisors, extracted and prepared, were acquired for this study and subsequently randomized into four groups (n = 10). The control group specimens underwent no pretreatment prior to the bleaching procedure, whereas the remaining three groups underwent air abrasion using distinct desensitizing powders; (a) Sylc, which contains bioglass 45S5; (b) BioMinF, which contains calcium phospho-fluoro-silicate glass; and (c) MI Pearls, which contains nano-hydroxyapatite, 1 h preceding the Opalescence Boost PF 40% bleaching procedure. Color measurements were conducted using a double-beam UV-Vis spectrophotometer at four distinct time points (prior to bleaching, 24 h, 15 days, and 30 days post-bleaching)., Results: Tooth color change outcomes revealed that there were no statistically significant results with respect to the interaction of the two criteria (treatments and time) (p = 0.990). Additionally, there were no statistically significant results with respect to the main effects of treatments (p = 0.385), while there were statistically significant effects with respect to the time criterion (p = 0.013)., Conclusions: The use of the tested desensitizing powders prior the bleaching procedure did not affect the tooth color change induced by the tested bleaching agent., Clinical Significance: Tooth color change and whiteness are not affected by air-abrasion desensitizing treatments when applied prior to in-office bleaching procedures., (© 2024 The Author(s). Journal of Esthetic and Restorative Dentistry published by Wiley Periodicals LLC.)

Objective This ex vivo study evaluated the effect of ultrasound and Er:YAG laser irrigation activation techniques on the penetration of sodium hypochlorite solution into infected human root canal dentin, providing a reference for clinical infection control of infected root canals. Methods Thirty-six cases of infected root canals were collected and randomly divided into three groups according to the irrigation technique: 12 cases in the conventional syringe irrigation (CSI) group, 12 cases in the passive ultrasonic irrigation (PUI) group, 12 cases in the Er:YAG laser and photon-induced photoacoustic streaming (PIPS) group and 36 cases of clean root canals (12 cases in the CSI group, 12 cases in the PUI group, 12 cases in the PIPS group). All of the selected root canals were straight root canals of posterior teeth. After standardizing the root length, all canals were subjected to instrumentation and dynamic irrigation. 2% methylene blue solution was used to visualize the penetration of the irrigant. EXAKT cutting and grinding equipment was used to take transverse sections of 100-150 μm at the coronal, middle and apical thirds of the root canals. The data (maximum penetration depth, average penetration depth, and penetration percentage) were observed under a light microscope to evaluate the effect of dye penetration. Results With the three irrigation techniques, the maximum penetration depth, average penetration depth and penetration percentage of the infected root canals were significantly lower than those of clean root canals in the full length of the root canal (P0.05). There was also no significant difference in the maximum penetration depth, average penetration depth or penetration percentage between the PIPS and PUI groups (P>0.05). Conclusion The dentine permeability of infected root canals was weaker than that of clean root canals. Er:YAG laser-assisted irrigation activation technology could significantly improve the penetration of sodium hypochlorite solution into infected dentin, but passive ultrasonic irrigation did not significantly improve the penetration.

Purpose: A novel anhydrous toothpaste formulation has been developed containing the anti-dentinal hypersensitivity (DH) ingredient stannous fluoride (SnF2).Materials and Methods: This randomised, controlled, examiner-blind, parallel-group, stratified (by baseline Schiff sensitivity score) study compared efficacy of an experimental 'Test' toothpaste (n = 67) containing 0.454% SnF2, 0.072% sodium fluoride and 5% sodium tripolyphosphate (all percentages w/w) with a negative 'Control' 0.76% sodium monofluorophosphate toothpaste (n = 68) in relieving DH in healthy Chinese adults. After 4-6 weeks acclimatisation, DH was assessed at baseline and following 4 and 8 weeks' twice-daily brushing by response to evaporative (air) (Schiff sensitivity score) and tactile (Yeaple probe) stimuli. An analysis of covariance model was used (factor: treatment group; covariate: baseline Schiff sensitivity score).Results: Both Test and Control toothpastes statistically significantly reduced Schiff sensitivity score from baseline after 8 weeks' use; the Test toothpaste also statistically significantly reduced the score after 4 weeks' use (all p < 0.001). The Test toothpaste reduction was statistically significantly superior to the Control toothpaste reduction at both timepoints (p < 0.001). Percentage differences in treatment effects between Test and Control groups were 24.1% at 4 weeks and 31.7% at 8 weeks. Tactile threshold scores for both treatments statistically significantly increased from baseline at both timepoints (all p < 0.001); however, there were no statistically significant differences between Test and Control groups. Both toothpastes were well-tolerated with no adverse events reported.Conclusion: The Test toothpaste containing 0.454% SnF2 reduced DH statistically significantly more than the Control as evaluated by the Schiff sensitivity score, but not by tactile threshold. [ABSTRACT FROM AUTHOR]

The number and the mean percentage tubular cross-sectional area of dentinal tubules per square millimetre were calculated in specimens of coronal dentine of 13 intact human third molar teeth from patients 18 to 28 years of age. The dentine was fractured at various known distances from the dentino-enamel junction. Near the dentino-enamel junction the number of tubules per square millimetre was 22000 and the mean tubular cross-sectional area was 3.6%. Midway between the pulpal wall and the dentino-enamel junction the number of tubules was 37000 mm-2 and the mean tubular cross-sectional area was 6.2%. Close to the pulp the number of dentinal tubules was 48000 mm-2 and the mean cross sectional area of tubules was 10.2 percent. The number of tubules per square millimetre more than doubled and the area occupied by tubules increased threefold from the dentine close to the dentine-enamel junction, to that close to the pulp. These differences in tubular patterns at different depths in dentine are clinically significant in dentine permeability, the treatment of traumatized teeth, and pain transmission in dentine. [ABSTRACT FROM AUTHOR]

Aim: Dental bleaching could adversely affect dentine hardness. The aim of the present study was to evaluate the effect of cervical dentine thickness on hardness reduction of outer dentine following intracoronal bleaching. Materials and methods: Thirty-six intact anterior teeth were selected and the root segments were separated 2 mm below the cementoenamel junction. Using a diamond fissure bar, dentine substrate was removed so that cervical dentine thickness in one part of the separated tooth was twice that in the other half. A resin-modified glass-ionomer cement plug was placed in 2-mm thickness from the apical side. Teeth were randomly divided into three groups (n = 12) to be treated with bleaching agents containing 35% hydrogen peroxide, sodium perborate, and distilled water in the control group. Vickers hardness numbers were measured for outer and inner dentine in each tooth sample. Data were analysed using Mann-Whitney U tests. Results: The mean Vickers hardness number between the two dentine thicknesses showed a statistically significant difference only in the sodium perborate bleaching group (P = 0.000). The mean Vickers hardness number of inner dentine was significantly higher in the small dentine thickness in comparison to the large dentine thickness (P = 0.000). The mean Vickers hardness number of outer dentine was significantly higher in the large dentine thickness in comparison to the small dentine thickness (P = 0.000). Conclusions: Within the limitations of this laboratory study, even in the presence of an orifice barrier, removal of excessive dentine from the root canal walls during root canal preparation could increase the damaging effect of bleaching materials on outer dentine microhardness. [ABSTRACT FROM AUTHOR]

The present study aimed to investigate the possible use of a non-instrumentation technique including blue light irradiation for root canal cleaning. Extracted human single rooted teeth were selected. Nine different groups included distilled water, NaOCl, intra-canal heated NaOCl, and NaOCl + EDTA irrigation after either instrumentation or non-instrumentation, and a laser application group following non-instrumentation technique. The chemical assessment of the root canal dentine was evaluated using energy dispersive spectroscopy (EDS) and Fourier transform infrared (FT-IR) spectroscopy. Surface microstructural analyses were performed by using scanning electron microscopy (SEM). The antimicrobial efficacy of different preparation techniques was evaluated using microbial tests. Light application didn't change the calcium/phosphorus, carbonate/phosphate and amide I/phosphate ratios of the root canal dentin. The root canal dentin preserved its original chemistry and microstructure after light application. The instrumentation decreased the carbonate/phosphate and amide I/phosphate ratios of the root canal dentin regardless of the irrigation solution or technique (p < 0.05). The application of light could not provide antibacterial efficacy to match the NaOCl irrigation. The NaOCl irrigation both in the non-instrumentation and instrumentation groups significantly reduced the number of bacteria (p < 0.05). The use of minimally invasive root canal preparation techniques where the root canal is not instrumented and is disinfected by light followed by obturation with a hydraulic cement sealer reduced the microbial load and preserved the dentin thus may be an attractive treatment option for management of vital teeth needing root canal therapy. [ABSTRACT FROM AUTHOR]

The aim of this study is to assess and analyze the intratubular penetration of the intracanal medications nitrofurantoin (Nit), triple antibiotic paste (TAP), and calcium hydroxide (CH). Sixty freshly extracted single-rooted teeth were acquired and decoronated to a standard length of 15 mm. To prepare specimens up to size F3, rotary ProTaper instrumentation was employed. The prepared teeth were divided into three groups, each of which received one of the tested intracanal medicaments: Group I (calcium hydroxide), Group II (triple antibiotic paste), and Group III (nitrofurantoin). Using a size #30 Lentulo spiral, a freshly prepared therapeutic paste was placed into the canals, and the intracanal medicaments were allowed to set in the incubator at 100% humidity. The samples were subsequently sliced perpendicularly to their long axis using a precision saw and assessed under a scanning electron microscope to assess the depth of penetration of intracanal medicaments at the coronal, middle, and apical portions of the root canal dentin. The data were analyzed using one-way ANOVA and Tukey's post hoc test. The statistical analysis revealed a significant difference between the experimental groups in the quantity and depth of sealer penetration (p < 0.05). In particular, as compared to the Nit group, both the CH and TAP groups had significantly smaller penetration areas (p < 0.05). In conclusion, this ongoing investigation indicates that nitrofurantoin penetrated dentinal tubules better than calcium hydroxide or triple antibiotic paste. [ABSTRACT FROM AUTHOR]

Background and Objectives: This prospective, comparative, double-cohort study aimed to compare the efficacy of silver diamine fluoride and potassium iodide (38% SDF+KI; Riva Star®) with sodium fluoride varnish (5% NaF; Duraphat®) in hypersensitive carious lesions in primary teeth to evaluate caries arrest and hypersensitivity relief. Materials and Methods: This study included thirty 2–5-year-olds (mean age = 3.67 ± 1.06 years; 16 males and 14 females) who required a desensitizing treatment for hypersensitive carious defects with visible dentin. A total of 15 of the participants were consecutively allocated to treatment with 5% NaF, and they were further compared to an equal number of participants treated with 38% SDF+KI solutions (n = 15). The treatments were performed following clinical evaluation of caries activity using the International Caries Classification and Management System (ICCMSTM) and the Bjørndal criteria (score of 0–9). Parental-reported hypersensitivity was evaluated using a visual analogue scale (0–10 = no to severe pain). Results: Clinical variables were evaluated at baseline and three months after treatment. Thereafter, a significant decline in hypersensitivity/pain led to lower final scores in the Riva Star® group (0.40 ± 1.12, p = 0.002) than in the Duraphat® group (1.40 ± 2.20, p = 0.004). The caries arrest effect was significantly higher in the Riva Star® group (86.7%) compared to the Duraphat® group three months after treatment (13.3%, p < 0.001). In both groups, there were no statistically significant differences in the children's behavior before, during, and after treatment. Conclusions: Ultimately, with both fluoride therapies reducing hypersensitivity/pain significantly, treatment with 38% SDF+KI was clearly more effective in caries arrest than 5% NaF varnish after a 3-month period. [ABSTRACT FROM AUTHOR]

The aim of this review was to provide dentists with comprehensive information regarding dentin hypersensitivity. This includes presenting its etiology, outlining the process of diagnosis, discussing clinical management strategies, and exploring technical approaches aimed at alleviating sensitivity. Dentin hypersensitivity is characterized by distinctive short, sharp pain arising from exposed cervical dentin in response to various external stimuli. The etiological factors cause two specific changes in teeth. First, the dentin surface must be exposed and denuded, which requires the loss of enamel or gingival recession combined with the loss of cementum. The second condition is the opening of the dentin tubules to allow the sensory mechanisms in the pulpal area following stimulation of the dentin surface. The accurate diagnosis of dentin hypersensitivity before receiving therapies is critical for successful treatment. The diagnosis of the disease starts through investigating the medical history of the patient and examination. In the examination, some techniques such as air stream and water rinsing are used in order to simulate the stimulating factors and to determine the degree of pain of the patient. Numerous materials and methods have been proposed to reduce or alleviate sensitivity. These materials typically exert their effects by either sealing dentin tubules or disrupting the transmission of nerve impulses. Generally, the primary approach in addressing dentin hypersensitivity involves the utilization of toothpaste containing potassium salts and fluoride. Newly introduced materials and in-office methods for treating dentin hypersensitivity include bioactive glasses, iontophoresis, CPP-ACP, and lasers. [ABSTRACT FROM AUTHOR]

Aim: The focus of the present research is to analyze the potential role of irrigants along with the activation system in the disinfection of the root canal space. Methods: Ninety root canals were randomly divided into two experimental groups based on the irrigants: Group I (n = 45) – Sodium hypochlorite irrigant and Group II (n = 45) –Chlorhexidine irrigant. The two groups are further subdivided into three subgroups base on the activation devices, i.e., passive ultrasonic irrigation, endoactivator, and laser. The first sample as a baseline, and the second sample was collected after the disinfection procedure. All the samples were streaked in brain − heart infusion agar plate to analyze the bacterial colony growth. The confirmatory analysis for the presence of Enterococcus faecalis was done using gram staining, biochemical analysis, and polymerase chain reaction. The nonparametric analysis was done using Kruskal–Wallis, Mann–Whitney U, and Wilcoxon signed-rank test and P < 0.05 was considered to be statistically significant. Results: The mean colony-forming unit was significantly reduced and there exhibited a statistically significant difference in pretreatment and posttreatment irrigated with sodium hypochlorite and chlorhexidine activated with passive ultrasonic activation with (P = 0.001), endoactivator with (P = 0.001), and laser with (P = 0.001). Conclusion: In consideration with advantage of the properties of both irrigants, the present study concludes a combined use with sodium hypochlorite during instrumentation followed by laser activation and a final rinse with chlorhexidine for a better eradication of the microbes from the root canal system thus preventing re-infection. [ABSTRACT FROM AUTHOR]

Introduction: This in vitro study aimed to evaluate the effect of different irrigation regimens on the chemical composition and cleanliness of root canal dentin. Materials and Methods: Forty-eight extracted single-rooted permanent human teeth were collected. Root canals were instrumented using step-back technique up to master apical file size 60. Samples were divided into 3 groups (n=16) based on the type of the irrigant used. The irrigation solutions were 5.25% sodium hypochlorite, 2% chlorhexidine gluconate, and saline solution as a control. Root canal cleanliness was assessed using stereomicroscope and scanning electron microscope. Scanning electron microscope energy dispersive X-ray was used for the inorganic analysis. Fourier transform infrared spectrometer was used for the organic analysis. One-way analysis of variance (ANOVA) and multiple comparison post hoc test were used for comparison between the three groups. Results: The highest mean percentage of remaining debris was in saline group followed by chlorhexidine gluconate group. Sodium hypochlorite group showed the lowest mean value of remaining debris. Furthermore, our results showed that canal irrigation with sodium hypochlorite affected the chemical structure of root canal dentin more than chlorhexidine gluconate. Conclusions: Based on the results, 5.25% sodium hypochlorite emerges as the preferred irrigant for root canal treatment. This research sheds light on the significance of irrigation regimens in endodontics and emphasizes the need for careful consideration of irrigant selection in clinical practice. [ABSTRACT FROM AUTHOR]

There are two main methods used for dentin hypersensitivity (DH) treatment: dentinal tubule occlusion and blockage of nerve activity. Dentifrices are the most common vehicles for active ingredients used for DH treatment. The aim of this study was to evaluate the efficacy of three toothpastes on dentinal tubule occlusion, mineral acquisition, and dentin hardness. Forty human dentin disks were submerged in 40% citric acid for 30 s and then exposed to tooth brushing for 2 min twice a day for 14 days using three toothpastes: Dontodent Sensitive (group 1), Dr. Wolff's Biorepair (group 2), and Sensodyne Repair and Protect (group 3). In the control group (group 4), the samples were brushed with water. All of the samples were evaluated using scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and Vickers dentin hardness determination. On SEM images, the degree of dentinal tubule occlusion was assessed using a five-grade scale. The mean score values in groups 1–4 were 3.60 ± 0.69, 2.20 ± 0.91, 2.30 ± 1.16, and 5.00 ± 0.00, significantly higher in study groups when compared to the control group (Kruskal Wallis test p < 0.05). EDX evaluation showed significantly higher calcium and phosphorus concentrations in groups 1 and 3 when compared to control group d. The mean values of Vickers dentin hardness numbers in groups 1–4 were 243.03 ± 10.014, 327.38 ± 56.65, 260.29 ± 37.69, and 225.83 ± 29.93, respectively. No statistically significant results were obtained when comparing the hardness mean values in groups (Kruskal-Wallis statistical test, p = 0.372 > 0.05). All three toothpastes tested demonstrated significant occlusion of dentinal tubules. Dontodent Sensitive and Sensodyne Repair and Protect toothpastes enhanced the calcium and phosphorus content of the dentin surface. None of the toothpastes increased dentin hardness as a result of mineral acquisition. [ABSTRACT FROM AUTHOR]

Sodium monofluorophosphate (Na2FPO3, MFP) is mainly used as an ingredient in fluoride-based dentifrices as it has a high safety profile, with one-third of the toxicity of sodium fluoride (NaF), as well as the ability to reach deep into the dentin. The purpose of this study was to assess the prevention of dentin erosion by MFP upon exposure to citric acid, which has a chelating effect, and to compare the effects to those of the conventional acidulated phosphate fluoride (APF) application method. Bovine dentin was used, and four groups were created: (i) APF (9000 ppmF, pH 3.6) 4 min group; (ii) acidulated phosphate MFP (AP-MFP, 9000 ppmF, pH 3.6) 4 min group; (iii) AP-MFP 2 min + APF 2 min (dual) group; and (iv) no fluoride application (control) group. Compared with the conventional APF application method, the application of AP-MFP was shown to significantly reduce substantial defects, mineral loss, and lesion depth; better maintain Vickers hardness; and promote the homogenous aggregation of fine CaF2 particles to seal the dentin tubules, enhancing acid resistance in their vicinity. The ΔZ value of the AP-MFP group was 2679 ± 290.2 vol% μm, significantly smaller than the APF group's 3806 ± 257.5 vol% μm (p < 0.01). Thus, AP-MFP-based fluoride application could effectively suppress citric acid-induced demineralization and could become a new, more powerful, and biologically safer professional-care method for preventing acid-induced dentin erosion than the conventional method. [ABSTRACT FROM AUTHOR]

This study examined how the tubular permeability in the apical 5 mm of mesial roots was affected by age, direction, distance from root apex, canal shape and canal number. Twenty mesiobuccal/mesial roots of maxillary/mandibular molars from three age groups (<30, 30–60, >60 years) were prepared. Maximal dye penetration in buccal, lingual, mesial and distal directions was measured at 1‐mm segment depth and analysed statistically. The <30 years group, when comparing to the >60 years group, had significantly deeper dye penetration in buccal and lingual directions. The permeability in proximal directions was not affected by either age or canal number. In the >60 years group, neither direction, segment depth nor canal number significantly impacted the permeability. However, these parameters significantly impacted samples younger than 60 years. Effective removal of infected root canal dentine would depend on age and its related preferred direction, distance from root apex and canal number. [ABSTRACT FROM AUTHOR]

Extraoral draining sinus of odontogenic origin usually lacks intraoral symptoms, thus it may be diagnosed as a cutaneous lesion. It is rare and may be confused with a wide variety of diseases for example furuncle, pericoronitis in relation to the mandibular third molars, parotid fistula, preauricular sinuses, periapical and periodontal pathology, and many more. Patients might seek treatment from their physician as they are not aware of its odontogenic origin and these cases usually are misdiagnosed and leading to inappropriate treatment. Objective: To discuss the detailed management of two cases of extraoral draining sinus that were successfully treated. Case Reports: The first case was referred by the Department of Oral and Maxillofacial Surgery, for management of extraoral draining sinus originating from tooth 36. In the second case, the extraoral draining sinus is caused by pulpal necrosis of several mandibular anterior teeth. Intra-radicular microorganisms in infected root canals primarily obligate anaerobes have been the aetiologic cause of apical periodontitis if left untreated may cause these types of symptoms. Conclusion: As it is uncommon and the absence of any dental symptoms, thus, it’s paramount important to diagnose these types of cases to treat the disease and to avoid unnecessary treatments such as prolonged prescription of antibiotics. Therefore, the dental cause should be ruled out for any cutaneous sinus tract so that a correct diagnosis can be ascertained, and proper management can be delivered to the patient. [ABSTRACT FROM AUTHOR]

The aim of this laboratory study was to investigate and compare the impact of five desensitizing techniques as a treatment fortooth sensitivity on the exposed dentin after an in-office tooth bleaching procedure. Thirty intact human molars were collected for this investigation. The specimens were obtained by transversely cutting 2.5 mm of the crowns, leading to exposure of the dentin. The specimens were cleaned in an ultrasonic bath and treated initially with EDTA gel 15% for 4 min and then with Opalescence Boost bleaching gel (40% H2O2) for two sets of 20 min. Then, the samples were randomly divided into six groups (n = 5) and received one of the following treatments: Group 1 (no treatment—control group), Group 2 (Emofluor gel—0.4% SnF2), Group 3 (MI Paste—CPP-ACPF), Group 4 (BioMinF paste—calcium phospho-fluoro-silicate), Group 5 (air-abrasion with ProSylc—Bioglass 45S5), and Group 6 (Er,Cr:YSGG laser). Subsequently, each sample was observed utilizing scanning electron microscopy (SEM) in order to detect the rate of occlusion of dentin tubules. SEM-EDS analysis revealed no occlusion of the dentin tubules in the control group, while Groups 2, 4, and 5 presented high effectiveness (>95% percentage of occluded tubules), and Groups 3 and 6 presented lower values (21.6 and 26.8%, respectively). It was concluded that althoughall the tested groups presented higher percentages of occlusion of the dentinal tubules compared to the control group, there were differences in effectiveness among them. The most effective treatments were the daily use of BioMinF paste and SnF2-containing gel, as well as air-abrasion with ProSylc powder. [ABSTRACT FROM AUTHOR]

To modify an adhesive system with halloysite clay nanotubes (HNTs) containing arginine and calcium carbonate and to evaluate their cytocompatibility, viscosity and efficacy in reducing dentin permeability. HNTs containing arginine and calcium carbonate were incorporated into the primer and adhesive of a three‐step adhesive system (SBMP), and their viscosity was measured. Discs (n = 4/group) were prepared: SBMP (control), HNT‐PR (modified primer), HNT‐ADH (modified adhesive) and HNT‐PR + ADH (modified primer and adhesive) were evaluated regarding cell death and viability. Dentin discs were prepared and randomly assigned into the following treatments (n = 10): NC (no treatment), SBMP, HNT‐PR, HNT‐ADH, HNT‐PR + ADH and COL (Colgate® Sensitive Pro‐relief™ prophylaxis paste). After, they were submitted to an erosive‐abrasive cycling. Dentin permeability (hydraulic conductance) was evaluated at baseline, 24 h after treatment and after cycling. Both the modified primer and adhesive showed significantly higher viscosity than their controls. Group HNT‐PR resulted in significantly higher cytotoxicity when compared to SBMP and HNT‐PR + ADH groups. Group HNT‐ADH resulted in the highest cell viability compared to all other groups. All groups showed significantly lower dentin permeability when compared to the NC group. Post‐cycling, SBMP and HNT‐ADH groups showed significantly lower permeability when compared to COL group. The addition of encapsulated arginine and calcium carbonate did not affect the cytocompatibility of the materials nor their ability to reduce dentin permeability. [ABSTRACT FROM AUTHOR]

Copyright of RSBO: Revista Sul-Brasileira de Odontologia is the property of UNIVILLE and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista ADM is the property of Asociacion Dental Mexicana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: There is still a lack of knowledge regarding the permeability and configuration of infected root dentin. The aim of this ex vivo study was to compare the dentin penetrability of healthy teeth and necrotic teeth with apical periodontitis by evaluating the penetration of sodium hypochlorite (NaOCl) and to analyze the histopathological features of root dentin. Methods: Forty-eight molars were collected and divided into two groups. The clinical diagnosis for one group was pulp necrosis with apical periodontitis and the pulp and periapex were normal in the other group. Forty-eight straight roots were divided into two groups: infected and healthy. First, all root canals were stained with 2% methylene blue to visualize penetration after standard root canal instrumentation and irrigation. Transverse sections were obtained, and the dye penetration parameters were measured. The cross sections were processed to 20–30 μm and stained with hematoxylin and eosin for observation of the histopathological changes in the root dentin. Results: The maximum penetration depth, median penetration depth and penetration percentage of NaOCl solutions, in infected root canals were significantly lower than those in healthy root canals. The histopathological analysis showed that the frequency of reparative dentin formation in infected root canals was significantly greater than that in healthy root canals. Conclusions: The dentin penetrability of teeth with necrotic teeth and apical periodontitis was more superficial during root canal irrigation than that of healthy teeth. The histopathological changes in infected radicular dentin, namely the formation of reparative dentin, might be associated with the lower permeability of dentin tubules in human teeth with apical periodontitis. [ABSTRACT FROM AUTHOR]

The objective of this article was to systematically provide an up-to-date review on the different methods of remineralizing human dentine using different biomimetic agents. The authors performed a systematic search within PubMed, Scopus, and Web of Science in addition to the grey literature in Google Scholar® using MeSH terms. The PICO question was P: human teeth dentinal sections; I: application of biomimetic remineralizing agents; C: other non-biomimetic approaches; O: extent of remineralization and physical properties of remineralized dentine. The initially identified studies were screened for titles and abstracts. Non-English articles, reviews, animal studies, studies involving the resin–dentine interface, and other irrelevant articles were then excluded. The other remaining full-text articles were retrieved. Bibliographies of the remaining articles were searched for relevant studies that could be included. A total of 4741 articles were found, and finally, 39 full-text articles were incorporated in the current systematic review. From these, twenty-six research studies used non-collagenous protein (NCP) analogs to biomineralize dentine, six studies used bioactive materials derived from natural sources, six studies used zinc hydroxyapatite, and one study used amelogenin peptide to induce hydroxyapatite formation on the surface of demineralized dentine. Additive effects of triclosan and epigenin were assessed when combined with commonly available NCPs. Overall, a moderate risk of bias was observed and, hence, the findings of the included studies could be acceptable. A meta-analysis of some similar studies was performed to assess the depth of remineralization and elastic modulus. Despite having high heterogeneity (I2 > 90), all the studies showed a significant improvement in biomimetic remineralization efficacy as compared to the control. All the included studies carried out a functional remineralization assessment and found a 90–98% efficacy in the extent of remineralization while the elastic modulus reached 88.78 ± 8.35 GPa, which is close to natural dentine. It is pertinent to note the limitations of these studies that have been carried out in vitro under controlled settings, which lack the effects of a natural oral environment. To conclude, the authors suggest that the biomimetic remineralization of dentine using NCP analogs, bioactive materials, and natural products carries significant potential in treating dentinal lesions; however, more long-term studies are needed to assess their clinical applications in vivo. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of human and bovine root dentin age on the bond strength of fiber posts fixed with resin cements. The degree of conversion (DC) of the resin cements in different root thirds also was evaluated. Materials and Methods: Ninety-six single-rooted teeth were divided into groups according to the origin and age: young human (20-30 years), old human (over 60 years), young bovine (24-36 months) and adult bovine (over 48 months). The teeth were endodontically treated, and fiber posts were cemented with resin cements (RelyX Ultimate and RelyX U200). After 24 h, the teeth were sectioned perpendicularly and the push-out test was performed in a universal testing machine at a speed of 0.5 mm/min, until failure. One specimen from each third from each group (n = 6) was selected, and the DC of the resin cements was analyzed by FT-Raman spectroscopy. Results: For both resin cements, the young human root dentin group presented the highest bond strengths and the old human root dentin group presented the lowest (p < 0.05). The bond strengths of bovine root dentin groups were not affected by aging (p > 0.05). For the DC of resin cements, there were differences among the root thirds (p < 0.05), with the lowest values observed in the apical third. Conclusions: The bond strengths were higher in the young human root canal than in the bovine substrate, with a negative effect of aging in the human substrate. The DC of dual-curing resin cements decreased from the coronal to apical root thirds. [ABSTRACT FROM AUTHOR]

The main goal of chemomechanical preparation is to remove microorganisms, pulp tissue remnants and dentine debris from the root canal system. Irrigation plays a major role in the cleaning and disinfection of the root canal. A large number of chemical compounds have been suggested over the years for use as irrigants during root canal treatment. At the moment there is no single irrigant that can satisfy all of these requirements, so a combination of irrigants is frequently used during treatment while seeking a balance between efficacy and safety. However, the need to use more than one solution also brings additional challenges because they may interact with each other inside the root canal. The aim of this article is to provide a critical review of the current evidence on the properties of the root canal irrigants, focusing particularly on those that are most widely used. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to evaluate the pH changes and penetration of hydrogen peroxide into radicular dentin when different protective bases were used with and without a bonding agent. Materials and Methods: In this in-vitro experimental study, 70 single-rooted bovine teeth were instrumented and obturated with gutta-percha. The guttapercha was removed 3mm below the cementoenamel junction (CEJ) and the teeth were divided into seven groups (n=10). In each group, 2mm base (1mm apical to the CEJ) was applied as follows: TheraCal LC, TheraCal LC plus SE Bond, Lime-Lite, Lime-Lite plus SE Bond, Ionoseal, Ionoseal plus SE Bond, and resin-modified glass ionomer (RMGI). The teeth were placed in vials containing distilled water, and pH values and molar concentration of the medium surrounding the teeth were recorded immediately after internal bleaching with 35% hydrogen peroxide. The pH values were also recorded at 1, 7, and 14 days following renewal of the medium. Data were analyzed with t-test, one-way ANOVA, and Kruskal-Wallis test. Results: After bleaching, the medium pH became acidic in all groups. There were no significant differences among groups in the mean pH of the medium after bleaching (P=0.189). Moreover, there were no significant differences among the study groups with respect to hydrogen peroxide concentration (P=0.895). Conclusion: Intra-orifice barriers such as light-cure resin-modified calcium hydroxide, light-cure resin-reinforced glass ionomer, and light-cure calcium silicate can be as effective as RMGI in providing coronal seal during intracoronal bleaching. [ABSTRACT FROM AUTHOR]