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Aim: To determine the effect of an herbal toothpaste containing Little Ironweed and Java Tea, on reducing dentine permeability in vitro. Materials and Methods: Dentine discs from human mandibular third molars were divided into three groups and brushed with herbal toothpaste, nonherbal toothpaste, or deionized water. Each group was immersed in artificial saliva (AS) or 6% citric acid. The permeability of each dentine disc was evaluated before and after saliva or acid challenge using a fluid filtration system. The morphology of dentine discs after treatment was observed using scanning electron microscopy (SEM). The mean permeabilities were statistically analyzed using analysis of variance and Tukey's test. Results: The nonherbal and herbal toothpaste groups demonstrated reduced dentine permeability. AS immersion decreased dentine permeability in both toothpaste groups with values lower than the control group. Dentine permeability values increased after acid immersion in the toothpaste groups and were similar to each other. SEM revealed small granular crystal-like and round particles on the dentine surface and opening of dentinal tubules of both toothpaste groups. More dentinal tubules were opened after brushing with deionized water. Conclusions: The reduction of dentine permeability caused by the herbal toothpaste was similar to that of the nonherbal toothpaste after brushing and the simulated oral conditions. Both herbal plants have the possibility to alleviate clinical hypersensitivity by reducing dentine permeability. Little Ironweed and Java Tea in the toothpaste composition is a potential choice for treating hypersensitive dentine. Graphical Abstract {Figure 4} [ABSTRACT FROM AUTHOR]

Abstract 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.

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]

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]

This study was evaluating how three desensitizing toothpastes used at home influence the effect associated with desensitizing agents after application in the clinic. Fifty dentine disks measure it permeability and 32 dentine disks with similar permeability levels were selected. Following Dental desensitizer treatment, dentine disks were randomly divided into three subgroups (n=10) that received applications of three toothpastes, respectively. The permeability (Lp) of each specimen was measured after each treatment. One specimen was selected from each group for scanning electron microscopy (SEM) observation. After each treatment, the Lp values decreased significantly for each group (p<0.05) and either completely or partially blocked the dentine tubules upon SEM observation. However, no significant differences in Lp values were observed amongst subgroups (p>0.05). After using the Dental desensitizer, Sensodyne, Crest and Colgate desensitizing toothpastes both can continued to reduce the permeability of the dentine disk, and no significant differences were found amongst them. [ABSTRACT FROM AUTHOR]

Objective: To assess the efficacy and safety of a toothpaste containing 7.5 % HX-BGC in combating dentinal hypersensitivity., Methods: A single-center, randomized, double-blind, three-group parallel-controlled design was employed, with Schiff Index and Yeaple Index as measurement indicators. The study evaluated the effectiveness of HX-BGC toothpaste, NovaMin toothpaste, and a negative control toothpaste without desensitizing agents. Eligible subjects underwent baseline examination after a 2-week washout period, and those meeting inclusion criteria and not meeting exclusion criteria entered the study. Participants were randomly assigned to use one of the three toothpastes. Follow-up examinations were conducted immediately after a single use and at 2, 4, and 6 weeks. Intra-group and inter-group comparisons were made for Schiff and Yeaple indices. Safety of the experimental toothpastes was assessed through participant feedbacks and oral soft tissue examinations., Results: Subjects in the three groups were balanced in terms of age and gender distribution, with no baseline differences in indicators. Immediately after a single application of toothpaste, Yeaple indices increased, and Schiff indices decreased, with no significant differences among the groups. After 2 weeks of continuous use, Yeaple indices increased in all groups, with significant differences observed between the HX-BGC group and the other two groups. Schiff indices decreased in all groups, with the NovaMin group showing significant differences compared to the negative control group. At weeks 4 and 6, both indices in the HX-BGC group and the NovaMin group were significantly better than those in the negative control group, with the HX-BGC group outperforming the NovaMin group in the Yeaple index. No serious adverse reactions related to the study products were observed or reported by any participants., Clinical Significance: This clinical trial confirmed the efficacy of HX-BGC in anti-dentinal hypersensitivity and supported the clinical application of the dentifrice containing HX-BGC., Conclusion: Compared to the negative control group, both HX-BGC and NovaMin toothpaste groups demonstrated more significant effects in combating dentinal hypersensitivity. No adverse reactions related to the experimental toothpastes were observed., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Aim: To assess the penetration of sodium hypochlorite (NaOCl) gel or NaOCl solutions with surfactants, and the effect of passive ultrasonic irrigation (PUI) on penetration into dentinal tubules. Methodology: Bovine incisor root canals were instrumented, the roots sectioned and the dentine blocks obtained were stained with crystal violet. Dentine blocks (n = 10 per group) were exposed to 3% NaOCl gel or 3% NaOCl solution for 10 and 20 min. Other dentine blocks (n = 10 per group) were exposed to Chlor‐Extra (6% NaOCl + surfactant), 6% NaOCl, 2.5% NaOCl with 0.2% cetrimide and 2.5% NaOCl for 10 and 20 min. The penetration depth of irrigants into dentinal tubules was measured in micrometres by viewing the bleached crystal violet under a stereomicroscope. Additionally, bovine incisor root canals, instrumented and stained with crystal violet, were distributed into two groups (n = 10) and irrigated with 2.5% NaOCl with PUI or conventional syringe irrigation (CSI). The penetration depth of irrigants into dentinal tubules was assessed 3 and 7 mm from the apex. Statistical analysis was performed by ANOVA and Tukey tests (α = 0.05). Results: There was significantly greater penetration of 3% NaOCl solution into dentinal tubules compared with the gel form (P < 0.05). There was no difference (P > 0.05) between 6% NaOCl and Chlor‐Extra, and between 2.5% NaOCl and 2.5% NaOCl + cetrimide. PUI significantly increased the penetration depth of NaOCl into dentinal tubules when compared with CSI (P < 0.05). Conclusions: In extracted bovine incisors, NaOCl gel penetrated less into dentinal tubules than NaOCl solution. The addition of surfactants did not increase the penetration depth. The use of PUI significantly increased NaOCl penetration into dentinal tubules. [ABSTRACT FROM AUTHOR]

Context: Eroded dentin might present the opening of dentinal tubules, increasing permeability, and consequently dentinal hypersensitivity. Aims: This study evaluated the permeability of dentin surfaces exposed to different levels of erosion and methods of surface protection. Materials and Methods: Dentine samples (3 mm × 3 mm × 1 mm) were prepared from bovine incisors (n = 90) and divided into three groups according to the method of controlling erosive challenge: Negative control, topical fluoride application, and glass ionomer sealant. Subsequently, they were randomly divided into three subgroups according to the exposure of simulated gastric acid solution (Demineralization - DES) (5% HCl, pH = 2.2), and remineralization (RE); negative control, 9 and 18 cycles DES-RE. The dentin permeability was measured by assessing the hydraulic conductance (μl/min.cmH2O.cm²). Statistical analysis was performed by two-way ANOVA and Tukey's test. Results and Conclusions: Greater permeability was observed after 18 erosive cycles, followed by exposure to 9 cycles and negative control (P < 0.0001). The application of glass ionomer sealant resulted in a major reduction of the hydraulic conductivity, regardless of the erosive challenge. Control groups and topical fluoride application showed similar results. In conclusion, the severity of erosive challenge contributed to the increase of dentin permeability. Besides, the glass ionomer sealant was the only protection agent that promoted significant effects in dentin permeability. [ABSTRACT FROM AUTHOR]

In recent years, scientists have developed various biomaterials to remineralize human teeth to treat dentine hypersensitivity. Poly(amido amine) (PAMAM) dendrimers have become a research focus in this field. It has been demonstrated that PAMAM is able to create precipitates both on the surface of and within the dentinal tubules, however, there is little information about its effect on reducing dentine permeability in vitro. This study aimed to evaluate the in vitro effectiveness and stability of the fourth generation amine-terminated PAMAM on dentinal tubule occlusion, especially on dentine permeability. Sodium fluoride (NaF), which has been widely used as a desensitizing agent, is regarded as positive control. Demineralized sensitive dentine samples were coated with PAMAM or sodium fluoride solutions and soaked in artificial saliva (AS) at 37 °C for different periods. Four weeks later, samples in each group were then equally split into two subgroups for testing using a brushing challenge and an acid challenge. Dentine permeability of each specimen was measured before and after each challenge using a fluid filtration system. Dentine morphology and surface deposits were characterized by scanning electron microscope (SEM) and analyzed with Image-Pro Plus software. Data were evaluated through multifactorial ANOVA with repeated measures and pair-wise comparisons at a level of 5%. The results showed that PAMAM and NaF significantly reduced dentine permeability to 25.1% and 20.7%. Both of them created precipitates on dentine surfaces after AS immersion for 28 days. PAMAM-induced biomineralization not only on dentine surfaces, but also deeper in dentinal tubules, significantly reduced dentine permeability. Moreover, PAMAM-induced biomineralization elicited excellent stable occlusion effects after acid challenge. In conclusion, PAMAM demonstrated a strong ability to resist acid and showed great potential to be used in the treatment of dentine hypersensitivity in future. [ABSTRACT FROM AUTHOR]

The present investigation evaluated the ability of an experimental di-calcium phosphate (DCP) desensitising agent used alone or combined with phytosphingosine (PHS) to occlude dentine tubules and resist a citric acid (CA) or artificial saliva (AS) challenge. Three groups of human dentine specimens (DS) were treated with the following: (1) PHS alone, (2) DCP or (3) a combination of PHS and DCP. Dentine hydraulic conductance of DS was evaluated using a digital flow sensor at 6.9 kPa. The average fluid volume for each of the treated DS was used to calculate the total dentine permeability reduction (%P) prior to and following CA immersion for 1 min or AS immersion for 4 weeks. The treated DS were subjected to both scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy analysis. Statistically significant differences (%P) were identified between the groups by ANOVA and Fisher's multiple comparison test (p < 0.05), respectively. Interestingly, both PHS and DCP appeared to work synergistically. DS treated with DCP or PHS/DCP demonstrated a significant reduction (%P) prior to and following CA or AS challenge (p < 0.05). Both the SEM and FTIR analyses showed consistent brushite crystals occluding the dentine tubules. Conversely, the application of PHS alone failed to demonstrate any significant reduction of dentine permeability (p > 0.05) or show any evidence of occlusion of the dentine tubules. DCP can be used alone or combined with PHS to decrease the dentine permeability as well as to resist a CA and AS challenge. These results would, therefore, suggest that DCP may be a suitable treatment option for dentine hypersensitivity. [ABSTRACT FROM AUTHOR]

Objective To determine the effects of the iontophoretic application of lignocaine and epinephrine to exposed dentine on the sensitivity of the dentine in human subjects. Design The experiments were carried out on 13 healthy premolars (13 subjects) that were scheduled for extraction. Dentine was exposed at the tip of the buccal cusp by cutting a cavity which was etched with 35% phosphoric acid. The sensitivity of the dentine was tested with probing and air blast stimuli. The subject indicated the intensity of any pain produced with a score of 0–100. In 7 teeth, the cavity was filled with a solution containing 20% (w/v) lignocaine HCl and 0.1% (w/v) epinephrine HCl, and an iontophoretic current of 120 μA was passed for 90 s. The sensitivity of the dentine was tested before and immediately after the treatment and then at 10 min. intervals for 40 min. Pulpal blood flow was recorded at each stage. Control experiments were carried out on 6 teeth using a solution containing only the epinephrine. Results The lignocaine plus epinephrine solution completely blocked the pain produced by both forms of stimulus immediately, and this continued for at least 40 min. It also produced an immediate fall in pulpal blood flow that also lasted for at least 40 min. The epinephrine solution had the same effect on pulpal blood flow but no effect on dentine sensitivity. Conclusions The topical application of 20% lignocaine and 0.1% epinephrine, with an iontophoretic current of 120 μA for 90 s, will anaesthetize exposed, normal, dentine. [ABSTRACT FROM AUTHOR]

Background This in vitro study aimed to assess the ability and efficacy of HX- BGC, a novel bioactive glass-ceramic (SiO2-P2O5-CaO-Na2O-SrO), to reduce dentine tubule permeability. Methods Dentine discs from human third molars were etched and randomly allocated into five groups: Group 1 - distilled water; Group 2 - Sensodyne Repair toothpaste (containing NovaMin®); Group 3 - HX- BGC toothpaste (containing 7.5% HX- BGC); Group 4 - control toothpaste (without HX- BGC); and Group 5 - HX- BGC powder. Specimens were treated daily by brushing with an electric toothbrush for 20 seconds. Between daily treatments (7 days total), specimens were immersed in artificial saliva for 24 hours. Dentine permeability was measured at baseline, after the first treatment, after the first 24-hour immersion in artificial saliva and at the end of day 7. Dentine morphology and surface deposits were observed by scanning electron microscopy after one day and 7 days of treatment, respectively. Results Sensodyne Repair and bioactive glass-ceramic toothpaste significantly and immediately lowered dentine permeability. The HX- BGC powder group showed the highest reduction in dentine permeability after 7 days of treatment. Conclusions The novel bioactive glass-ceramic material HX- BGC is effective in reducing dentine permeability by occluding open dentine tubules, indicating that HX- BGC may be a potential treatment for dentine hypersensitivity. [ABSTRACT FROM AUTHOR]

Objective To evaluate the flow dynamics of dentine fluid using a chemiluminescence method in vitro . Materials and methods Horizontally sliced coronal dentine specimens with thicknesses of 1.4, 1.6, 1.8, and 2.0 mm ( n = 10 each) were prepared from extracted human third molars. After cleaning with EDTA, a mounted specimen was clamped between 2 acrylic chambers attached to both the occlusal and pulpal sides. The occlusal chamber, which was closed with a glass coverslip, was filled with a chemiluminescent solution (0.02% luminol and 1% sodium hydroxide in water). A trigger solution of 1% hydrogen peroxide and 1% potassium ferricyanide was injected into the pulpal chamber at a constant pressure of 2.5 kPa, and allowed to immediately flow into the patent dentinal tubules. Four consecutive measurements (T1–T4) were performed on each sample by recording the emission of chemiluminescence with a photodetector. The relationship between the crossing time of the liquid through the slice and dentine thickness was examined. Results An apparent time delay was detected between the starting points of the trigger solution run and photochemical emission at T1. Dt (Dt, s) values of each thickness group were 13.6 ± 4.25 for 1.4 mm, 18.1 ± 2.38 for 1.6 mm, 28.0 ± 2.46 for 1.8 mm, and 39.2 ± 8.61 for 2.0 mm, respectively. Dt significantly decreased as dentine became thinner towards the pulp chamber ( P < 0.001). Conclusions The velocity of fluid flow increased both with increasing dentine depth or reduction of remaining dentine thickness. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To determine the effect of topical applications of 50% (w/v) lignocaine HCl on the sensitivity of human dentine. Design: The experiments were carried out on 12 premolars scheduled for extraction as part of orthodontic treatment in nine subjects (ages: 16–29 years). Dentine was exposed by cutting a cavity at the tip of the buccal cusp of each tooth, and etched with 35% phosphoric acid. The sensitivity of the exposed dentine to probing and air-blast stimuli was assessed before and after applying either 50% (w/v) lignocaine HCl solution or distilled water to the exposed dentine for 10min. Changes in the sensitivity of the dentine were monitored for up to 160min. The subject indicated the intensity of any pain produced by marking a 100mm visual analogue scale (VAS). Results: Before treatment, both forms of stimulus evoked pain in all the teeth. The median VAS score with probing was 40mm and, with air-blast stimulation, 30mm. 50% lignocaine HCl produced a progressive fall in these scores and after 30min there was no response to either probing or air-blast stimulation. The responses started to return 30–160min after the lignocaine had been washed off. Water had no effect. Conclusions: Lignocaine will diffuse into exposed dentine and block the pain evoked by probing and air-blast stimuli provided that a sufficiently steep diffusion gradient is created. A topical application of a 50% (w/v) solution of lignocaine HCl for 10min will anaesthetise dentine within 30min. [Copyright &y& Elsevier]

Abstract: Objective: To evaluate in vitro the effectiveness of different calcium-silicate (CS) cements specifically designed for dentine permeability reduction. Design: Fifty dentine discs were prepared from caries free human molars extracted for surgical reasons. The treatment consisted in applying two different experimental CS cements on dentine surface. Dentine discs treated only with EDTA served as negative control group. Treatment with D-Sense Crystal and Clearfil S3-Bond served as positive control groups. After treatment samples were immersed in artificial saliva. The quantitative changes in the hydraulic conductance (i.e. permeability) through dentinal tubules were quantified using a hydrostatic device working at 6.9kPa. Dentine permeability was measured immediately after EDTA treatment, 10min and 1 week after treatment application and immersion of dentine samples in artificial saliva. SEM/EDX analyses were performed to obtain qualitative information on dentine morphology and surface deposits. Results: The experimental CS cements reduced dentine permeability immediately after application and also 10min and 1 week after the immersion of the specimens in artificial saliva. D-Sense Crystal and Clearfil S3-Bond showed higher levels of dentine permeability after 1 week of immersion in artificial saliva. Conclusions: CS cements reduced dentine permeability in vitro even after immersion in artificial saliva, which makes them new valuable candidates for treatment of dentine hypersensitivity in vivo. [Copyright &y& Elsevier]

The aim of the present study was to determine clinical parameters for the use of Er,Cr:YSGG laser in the treatment of dentine hypersensitivity. Two antagonist areas were determined as control and experimental areas for irradiation in 90 premolar roots. Each surface was conditioned with 24% EDTA (sub-group 1) and 35% phosphoric acid (sub-group 2) and irradiated with the following settings: 1) Er:YAG, 60 mJ, 2 Hz, defocused; groups 2 to 9: irradiation with Er,Cr:YSGG laser, 20 Hz, Z6 tip, 0% of air and water: 2) Er,Cr:YSGG 0.25 W; 3) 0.5 W; 4) 0.75 W; 5) 1.0 W; 6) 1.25 W, 7) 1.50 W, 8) 2 W; 9) 2 W. After irradiation, samples were immersed in methylene blue solution and included in epoxy resin to obtain longitudinal cuts. The images were digitalized and analyzed by computer software. Although the samples irradiated with Er:YAG laser showed less microleakage, sub-group 1 showed differences between the groups, differing statistically from groups 3, 6, and 9. The results of sub-group 2 showed that the mean values of Er:YAG samples showed a negative trend, however, no differences were detected between the groups. For scanning electron microscopy analysis, dentine squares were obtained and prepared to evaluate the superficial morphology. Partial closure of dentinal tubules was observed after irradiation with Er:YAG and Er,Cr:YSGG laser in the 0.25 and 0.50 W protocols. As the energy densities rose, open dentinal tubules, carbonization and cracks were observed. It can be concluded that none of the parameters were capable of eliminating microleakage, however, clinical studies with Er:YAG and Er,Cr:YSGG lasers should be conducted with the lowest protocols in order to determine the most satisfactory setting for dentine hypersensitivity. [ABSTRACT FROM AUTHOR]

Objectives: The exposure of dentinal tubules causes fluid movement and dentinal hypersensitivity. This study aimed at evaluating the dentine permeability after prophylactic measures performed on exposed dentine after immersion in artificial saliva and citric acid challenge. Confocal microscopy was performed to evaluate the percentage of occluded tubules (OCT%) and the changes in dentine morphology.Methods: Prophy-powders and pastes were tested in this study. An oxalic acid liner was used as a positive control. Dentine discs from human third molars were treated with each material and the dentine permeability was evaluated using a fluid filtration system working at 20cm H(2)O. Artificial saliva and citric acid were used for the determination of changes in dentine permeability. The percentage of tubule occlusion capability (OCT%) was evaluated using confocal microscopy.Results: All the products used in this study were able to significantly reduce the dentine permeability of acid-etched specimens. The use of the bioactive glass and sodium bicarbonate showed the highest values in dentine permeability reduction. However, the air-polishing procedures performed with Sylc bioactive glass powder created a dentine surface resistant to citric acid attack.Conclusion: Bioactive glass is suitable for treatment of dentinal hypersensitivity by creating a dentine surface resistant to citric acid attack. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: The purpose of this study was to evaluate the in vitro effectiveness of a new bioglass-containing and two commercial desensitising toothpastes on dentinal tubule occlusion after citric acid challenge or artificial saliva (AS) immersion. Methods: One hundred dentin discs from human third molars were used. Specimens were randomly divided into five groups (n =20), Group 1: EDTA-treated dentin; Group 2: brushing with distilled water; Group 3: brushing with Novamin; Group 4: brushing with Sensodyne Freshmint; Group 5: brushing with Colgate Sensitive. In each group, samples were then equally split into two subgroups (n =10) to test two post-treatments: 6% citric acid challenge or 24h immersion in artificial saliva. Dentine permeability of each specimen was measured before and after each treatment using a hydrostatic device working at 20cm H2O pressure. Data were analysed by two-way repeated measures ANOVA to determine if there were any significant differences within or between groups. Dentine morphology and surface deposits were observed by SEM. Results: All three desensitising toothpastes significantly reduced dentine permeability and created precipitates on the treated dentine surfaces. Moreover, the reductions in dentine permeability showed partial recovery after a citric acid and artificial saliva immersion. Sensodyne showed significant resistant to acid attack and Novamin exhibited the lowest permeability after artificial saliva immersion for 24h. Conclusions: The application of the three toothpastes resulted in effective dentinal tubule occlusion. However, the new bioglass-containing toothpaste (Novamin) represented excellent occlusion effects after brushing treatment and AS immersion, while Sensodyne demonstrated more reduction in permeability when citric acid challenged. [Copyright &y& Elsevier]

Aim To examine the effects of various root canal irrigants on cervical dentine permeability by monitoring the diffusion of hydrogen peroxide (H2O2). Methodology Sixty cervical dentine discs were prepared from human third molar teeth. After removal of enamel and cementum, the outer dentine surface was etched with 17% ethylenediamine tetraacetic acid (EDTA) for 1 min. The dentine discs were randomly assigned to five groups according to the irrigant used: A, saline solution; B, 2.5% sodium hypochlorite solution (NaOCl); C, 5% NaOCl; D, 17% EDTA and 2.5% NaOCl; E, 17% EDTA and 5% NaOCl. After irrigation on the inner dentine surface with the various solutions, the diffusion of 30% H2O2 was evaluated through each disc using a plastic-split chamber. H2O2 was applied to the inner-side chamber, while the outer-side chamber was filled with de-ionised water. After 30 min of application of H2O2, the solution in the outer-side chamber was collected to determine the concentration of H2O2 using a spectrophotometer. Results The penetration of H2O2 through dentine in group E was significantly highest, followed by groups D, C, B and A respectively (one-wayanova, P < 0.05). Conclusions Among the irrigants used, 17% EDTA and 5% NaOCl had the greatest effect in increasing dentinal permeability to H2O2. [ABSTRACT FROM AUTHOR]

Abstract: Objective: This study aimed to verify whether two demineralisation solutions, with different fluoride concentrations, would produce subsurface lesions in dentine, as assessed by microradiography, with different mineral loss profiles and, subsequently, to determine the dentine permeability of the two altered tissues. Methods: Forty-five human coronal portions were prepared and randomly divided into two test groups (20 specimens each) with the remaining five as a control group. Each test group was exposed to a demineralisation solution containing either 1 or 5ppm fluoride for five days. Results: There were highly significant differences between the two test groups for all microradiographic parameters, except for lesion depth. The increase in dentine permeability from baseline to day 5 was statistically significant within each of the two test groups, but not for the control group. Conclusion: The differences in the mineral content profile of the two lesions did not influence the magnitude of change in their permeability. [Copyright &y& Elsevier]

Abstract: This study evaluated the effect of 980-nm diode laser at different parameters on root canal dentin permeability associated with different irrigants. Seventy-five canines were sectioned at 15 mm from the apex, prepared mechanically up to #40 .02 instrument, and irrigated with 2 mL distilled water. Final irrigation (10 mL) was used as follows: (1) distilled water; (2) 1% NaOCl; (3) 17% ethylenediaminetetraacetic acid + a cationic surfactant cetyltrimethylammonium bromide (EDTAC). Laser was applied at 1.5 or 3.0 W as either continuous wave or pulsed wave (100 Hz). The teeth were then processed histochemically, the percentage of copper ion penetration into the dentin of the canal walls was counted, and the data were analyzed statistically with the Tukey-Kramer test (α < .01). When laser was associated with water, an increase in permeability was found, whereas permeability decreased when associated with EDTAC. Dentin permeability after laser irradiation was directly dependent on the solution used for final irrigation. [Copyright &y& Elsevier]

Abstract: Objectives: The incorporation of antibacterial agents into adhesive systems has been proposed to eliminate residual bacteria from dentine. This study used the agar diffusion method to evaluate the antibacterial activity of Clearfil Protect Bond (CPB), Clearfil SE Bond (CSEB), Clearfil Tri-S Bond (C3SB) and Xeno-III (XIII) self-etching adhesive systems, with or without light-activation, against cariogenic bacteria, and to assess the influence of human dentine on the antibacterial activity of these materials. Methods: An aliquot of 10μl per material (and individual components) were pipetted onto paper and dentine discs distributed in Petri dishes containing bacterial culture in BHI agar. Positive control was 0.2% chlorhexidine digluconate (CHX). Results: After incubation, the adhesive components of CPB and CSEB, liquid A of XIII and C3SB did not present antibacterial activity when applied to paper discs. The non-light-activated CPB primer+adhesive promoted the greatest inhibition of Streptococcus mutans (p <0.05), whereas with light-activation, there was no significant difference between primer+adhesive and primer alone. For Lactobacillus acidophilus, CPB primer presented the greatest antibacterial activity in both light-activation conditions (p <0.05). Regarding the dentine discs, only CHX promoted an inhibitory effect, though less intense than on paper discs (p <0.05). CHX presented greater antibacterial activity against S. mutans than against L. acidophilus (p <0.05). Conclusions: Light-activation significantly reduced the antibacterial activity of the self-etching adhesive systems; MDPB incorporation contributed to the effect of adhesive systems against cariogenic bacteria; the components eluted from the adhesive systems were not capable to diffuse through 400μm-thick dentine disc to exert their antibacterial activity against cariogenic bacteria. [Copyright &y& Elsevier]

Abstract: Objective: The aim of this study was to determine the repeatability of apparatus designed to assess dentine permeability at two different pressures. Method: Forty-five human coronal tooth portions were prepared and permeability was measured at two separate time points, 5h apart, at 14cmH2O pressure and then at 100cmH2O pressure. Repeatability was determined using the limits of agreement (LOA) method. Results: The results showed equal mean permeability of 0.6μl at both time 1 and time 2 at 14cmH2O pressure, and 2.7 and 2.5μl at time 1 and time 2, respectively, at 100cmH2O pressure. At 14cmH2O pressure, the LOA were (−0.4, 0.4)μl and at 100cmH2O pressure the LOA were (−0.2, 0.6)μl. Conclusion: Although repeatability measurement at 14cmH2O pressure appeared to be acceptable, the higher permeability values at 100cmH2O pressure may make the latter the pressure of choice despite the small bias. [Copyright &y& Elsevier]

Abstract: Objectives: The objectives of this experiment were to determine in vitro the permeability of teeth exhibiting a range of natural dentine caries and the effects of caries excavation and subsequent restoration on the dentine permeability of extracted teeth. Methods: Forty-five human permanent molars with obvious occlusal caries were selected and coronal dentine permeability was measured before (baseline) and after caries excavation, as well as after acid etching the prepared cavity and finally, after restoration. Results: The small permeability values for all teeth made statistical testing between the different stages of specimen preparation both meaningless and inappropriate. An alternative means of examining the data was to calculate the percentage of teeth which had exhibited permeability values greater than zero at each of the four specimen preparation stages. The percentage of teeth with permeability greater than zero remained unchanged before and after cavity preparation (23%). Removal of the smear layer, however, increased substantially the percentage of teeth demonstrating permeability greater than zero, to 72%. None of the restored teeth demonstrated measurable permeability. Conclusion: The teeth chosen exhibited a range of dentine caries and, surprisingly, demonstrated either low or no measurable permeability. This experiment highlighted the need for more investigation into the quality of carious-affected dentine and the properties of the smear layer produced from such dentine. [Copyright &y& Elsevier]

The aim of this study was to evaluate the ability of five experimental resins, which ranged from hydrophobic to hydrophilic blends, to seal acid-etched dentine saturated with water or ethanol. The experimental resins (R1, R2, R3, R4, and R5) were evaluated as neat bonding agents (100% resin) or as solutions solvated with absolute ethanol (70% resin/30% ethanol). Fluid conductance was measured at 20 cm H2O hydrostatic pressure after sound dentine surfaces were: (i) covered with a smear layer; (ii) acid-etched; or (iii) bonded with neat or solvated resins, which were applied to acid-etched dentine saturated with water or ethanol. In general, the fluid conductance of resin-bonded dentine was significantly higher than that of smear layer-covered dentine. However, when the most hydrophobic neat resins (R1 and R2) were applied to acid-etched dentine saturated with ethanol, the fluid conductance was as low as that produced by smear layers. The fluid conductance of resin-bonded dentine saturated with ethanol was significantly lower than for resin bonded to water-saturated dentine, except for resin R4. Application of more hydrophobic resins may provide better sealing of acid-etched dentine if the substrate is saturated with ethanol instead of with water. [ABSTRACT FROM AUTHOR]

Summary: Purpose:: To determine whether transducers could provide a convenient method of measuring dentine permeability and to investigate the effects of removal of pulp tissue and perfusion time on the pressure increase across human dentine after low-pressure perfusion. Method:: Human premolar teeth that had been stored for 1–2 months were prepared for full crown preparations. The pulp tissue was removed from half the samples and all the coronal segments perfused with saline at 1.3kPa for varying times. An external pressure was then applied and the response within the pulp chambers recorded with transducers. Results:: Extirpation of pulp tissue reduced the rate of rise of pressure inside the pulp chamber by approximately 50%. Perfusion at 1.3kPa for up to 1h had no effect on pressure rise, but 6h of perfusion produced a very significant increase. Conclusion:: Transducers can provide a relatively simple, convenient and clinically relevant measurement of dentine permeability. For stored coronal segments that have been perfused at physiological pressures, extirpation of pulp tissue and perfusion time have significant effects on pressure transmission across dentine. [Copyright &y& Elsevier]

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]

The aim of this study was to evaluatein vitrodentine permeability evaluation of 2-Hydroxyethyl methacrylate (HEMA)-based desensitizing products using split-chamber model followingin vivoapplication in the dogs for three experimental time periods of 1 week, 1 month and 3 months. Buccal enamel of upper and lower canines of nine young dogs was removed and flat dentinal surface was obtained using a water-cooled diamond bur. The dentinal surface divided into four quarters, three experimental and a control. Health-Dent and Gluma Desensitizing agent and Single bond were applied to respective quarters of one tooth, according to manufacturers’ instructions. The last quarters were left as control without any applications. For the each experimental period, 10 dentine samples from each group including control were used to measure the hydraulic conductance values. The dentine discs were placed pulp-side down in a split-chamber device in which the plastic spacers containing the rubber 0 rings have a surface area of 1 mm2 and permeability was measured by fluid filtration. The data were expressed as hydraulic conductance (Lp). Differences in dentine permeability obtained for the desensitizing agents against the control were tested for statistical significance using Kruskal–Wallis one-wayanovaand Bonferroni-adjusted Mann–WhitneyU-tests. Differences in permeability in three time periods for each desensitizing agent were analysed using Friedman'sanovaand Wilcoxon signed rank tests. All desensitizing applications caused decreased Lp values compared with the control Lp value at the end of 1 week. In the 1-month samples, between the Lp values of Single bond and control, no statistical difference was found (P > 0·05). At the end of the 3-month period, the Gluma Desensitizing agent had the lowest the Lp value (P < 0·05). The result of this study is that the topical application of desensitizing agents led to decrease in dentine permeability in the dog model. The Gluma Desensitizing agent provide the more lasting tubule-occluding effect than the other material tested in this model. [ABSTRACT FROM AUTHOR]

Objective. The aim of this study was to determine whether a dentine bonding agent (DBA) had an effect in reducing fluid filtration under cemented provisional crowns.Methods. Crown preparations on 34 premolars, randomly allocated to two equal-sized test and control groups, were assessed for dentine permeability by a fluid filtration technique. In the test group, prepared crowns were acid-etched and then treated with a DBA (Prime & Bond NT). In the control group, no such DBA was applied. Provisional crowns were cemented on both groups of teeth using non-eugenol zinc oxide cement. Fluid filtration rates were measured repeatedly after crown preparation, at cementation, 1 h, 1 day, 1 week and 3 weeks following crown cementation for both groups. Filtration rates were also measured after acid-etching and dentine bonding for the test group.Results. There was insufficient evidence to suggest any statistically significant differences either between the two groups or, on average, across the five time points in each group in terms of the relative percentage of fluid filtration.Conclusion. The DBA used did not seal dentinal tubules any more than did the smear layer and provisional crowns luted with a non-eugenol ZnO cement. [Copyright &y& Elsevier]

Hülsmann M, Heckendorff M, Lennon Á. Chelating agents in root canal treatment: mode of action and indications for their use – a review. International Endodontic Journal, 36, 810–830, 2003. Chelating agents were introduced into endodontics as an aid for the preparation of narrow and calcified root canals in 1957 by Nygaard-Østby. A liquid solution of ethylenediaminetetraacetic acid (EDTA) was thought to chemically soften the root canal dentine and dissolve the smear layer, as well as to increase dentine permeability. Although the efficacy of EDTA preparations in softening root dentine has been debated, chelator preparations have regained popularity recently. Almost all manufacturers of nickel–titanium instruments recommend their use as a lubricant during rotary root canal preparation. Additionally, a final irrigation of the root canal with 15–17% EDTA solutions to dissolve the smear layer is recommended in many textbooks. This paper reviews the relevant literature on chelating agents, presents an overview of the chemical and pharmacological properties of EDTA preparations and makes recommendations for their clinical use. [ABSTRACT FROM AUTHOR]

Objectives. The aim of our in vitro study was to contribute to an elaboration of a protocol to evaluate the permeability of dentin and the effect of different acid conditioners by means of the electrochemical impedance technique.Materials and methods. Twenty-four 1.1 mm thick dentin disks were embedded in a hollow polyurethane resin cylinder. The system used was a ‘like’ permeation cell: two electrodes immersed in a 10−1 KCl solution were attached to a potentiostat. It was connected to a microcomputer controlled frequency response analyzer and a 10 mV sinusoidal voltage signal over a frequency range of 1 Hz to 65 kHz was applied between the electrodes. The current passing through the dentin was measured to enable a calculation of impedance expressed in a complex number. To establish an evaluation of permeability variation, the resistance was noted for all specimens before and after the application of dentin conditioners.Results. The highest resistance decrease was obtained with 32% phosphoric acid and 10-3 solution which improved the permeability, respectively, 9.0 and 6.9% with no significant difference. The acidic monomer can be considered as intermediate (4.3%) between 10-3 solution and the polyacrylic acid (2.8%) with no significant difference.Conclusions. By measuring electrical resistance of dentin disks with the impedance method, we can evaluate the ionic conduction through the sample and achieve quantitative values about permeability. The action of dentin conditioners can be significantly evaluated regarding their action in terms of resistance of the etched zone (REZ) and increasing dentin permeability. [Copyright &y& Elsevier]

The responses of intradental nerves can be blocked by 50% lidocaine applied to exposed, etched dentine. The aim here was to analyse electrophysiologically the contribution of pulpward pressure to the anaesthetic effect of lidocaine applied to exposed dentine. In 17 adult cats with intact lower canines, approximately 1 mm of the coronal tip of the canine was removed and the exposed dentine acid-etched. Pulpward pressure was applied to the exposed dentine through a chamber fixed to the tip of the tooth. Cervical and coronal electrodes of silver wire and Ag/AgCl mixture were placed, the cervical 2 mm from the gingival margin of the canine and the coronal into the coronal pulp chamber. The inferior alveolar nerve was surgically exposed and single pulpal nerve fibres responding to electrical stimulation of the canine were identified. The chamber was filled with 50% lidocaine solution, and 0 (atmospheric pressure), 1.3, 5.0 or 10.0 kPa pressure was applied to the chamber for 20 min. Orthodromic and antidromic action potentials were compared before and after the lidocaine application. When lidocaine was applied at 0, 1.3 or 5.0 kPa (n=5 each) for 20 min, all the orthodromic responses to cathodal electrical stimulation with the coronal electrode were blocked. Almost all orthodromic responses (12/15) remained unblocked when the cathodal electrical stimulation was applied with the cervical electrode. Applying 10.0 kPa pressure to the lidocaine solution blocked all the pulpal nerve responses (n=5) to both stimulation modes. The amplitude of the antidromic compound action potential was significantly decreased when the applied pressure was increased. These results suggest that increased pulpward pressure may effectively force anaesthetic solution more rapidly through the dentinal tubules into the pulp. [Copyright &y& Elsevier]

Objective. To compare the permeability of the occlusal and the cervical dentinal regions within the same tooth, which represent the bottom of Class I and V cavities, respectively, with two different compositions of perfusion fluid, in vitro.Methods. An occlusal and a buccal disc were cut from each extracted third molar at a level close to the pulp chamber. The convective permeability of the discs was measured in a fluid transport model using de-ionised water or 1:3 diluted bovine serum and the hydraulic conductance was determined.Results. The mean hydraulic conductance values of the occlusal and the buccal cervical human dentine to water were 0.069 and 0.047 μl min−1 cm−2 cm H2O−1, respectively. When diluted bovine serum was used, the corresponding values were 0.036 and 0.012 μl min−1 cm−2 cm H2O−1, respectively. Statistical analysis revealed no significant difference between the permeability of these two regions. The composition of the perfusion fluid significantly influenced the permeability of dentine.Conclusions. The occlusal and the buccal cervical regions of human dentine have similar permeability characteristics in vitro. There is a strong reverse correlation between the viscosity of the perfusion fluid and the perfusion through the dentine. [Copyright &y& Elsevier]

The permeability, temperature and morphologic changes of the wall of the root canal induced by Nd:YAG, CO2 and argon lasers were studied. The changes were evaluated according to the presence or absence of a smear layer. Root canals of 140 human single-rooted teeth were enlarged using a step-back technique. Permeability was evaluated by the extent of methylene blue dye penetration into the tubules. Temperature changes were measured using a thermo-vision system, and morphological changes were evaluated by scanning electron microscopy. Laser energy was delivered into the canal by means of a flexible optical fibre or metal tip. There were statistically significant differences in permeability between lased groups with and without a smear layer in the cervical third of the root canal following lasing. In the middle third of the root canal, all three laser types induced permeability increases in groups with a smear layer. In the apical third, statistically significantly decreases in permeability were observed among CO2 laser and Nd:YAG compared with control group (P<0.01). Rises in temperature ranged from a minimum of + 10.1 °C (CO2 laser) to a maximum of + 54.8 °C (argon laser). All three laser devices appeared capable of producing a glazed-like surface and craters. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the penetration of smeared and nonsmeared dentine by Strep-tococcus gordonii. Prepared human roots, grouped as either nonsmeared or smeared, were immersed in a suspension of S. gordonii cells for 3 weeks. The roots were then prepared for scanning electron microscopy and histological analysis. Dentine discs prepared from coronal dentine were grouped similarly. Using a fluid filtration apparatus, the hydraulic conductance (Lp) of each disc was determined before and after incubation with bacterial suspension. Scanning electron microscopy evaluation of the roots following infection with bacteria showed no change in the smear layer (P<0.0001). Histological sections revealed that bacterial penetration of all the nonsmeared samples had occurred, while nine out of 10 smeared samples showed no bacterial penetration (P<0.0001). The Lp of the nonsmeared discs was significantly reduced by 42% (P<0.0001) after bacterial penetration. However, the smeared samples revealed a 1% reduction in Lp which was not significant (P>0.05). The results suggest that dentinal smear layers are an effective barrier to dentinal tubule invasion by S. gordonii. [ABSTRACT FROM AUTHOR]

The effect of 5% sodium hypochlorite and 35% hydrogen peroxide on dentine samples in vitro was investigated. It was demonstrated that both 5% NaOCI and 35% H2O2 depletes the dentine, which can he recorded as weight loss. Sodium hypochlorite removes approximately 14% of dry weight from dentine samples in 24 h; hydrogen peroxide is half as destructive. The hydraulic conductance (Lp;) of dentine after treatment with NaOCI is increased over 100%. It is suggested that the use of high concentrations of sodium hypochlorite during root canal treatment may negatively affect the integrity of the root canal wall thereby allowing increased access of caustic bleaching fluids to cervical vital tissues. [ABSTRACT FROM AUTHOR]

The development of external cervical root resorption following internal bleaching of discoloured pulpless teeth is associated with the use of hydrogen peroxide. The aim of the study was to determine radicular penetration of hydrogen peroxide following intracoronal bleaching with various forms of sodium perborate. 63 extracted human incisors were root filled and stained artificially. Standardized cementum defects were created on the mesial and distal aspects of the root directly below the cemento-enamel junction (CEJ). Using the walking bleach technique all teeth were bleached for a 6-day period, with replacement of the bleaching paste after days 1 and 3. Sodium perborate monohydrate (MH), trihydrate (TRH) or tetrahydrate (TH) was mixed with H2O2 or H2O and subsequently placed intracoronally 1 mm below the labial CEJ. The teeth were divided into six groups: I. MH + H2O2(30%) (n=12); II. TRH + H2O2(30%) (n=12); III. TH + H2O2(30%) (n=12); IV. TH + H2O (n=12); V. TH + H2O, gel (n=12); VI. no bleaching paste (n=3). At baseline and at days 1 3 and 6 the amount of H2O2 taken up from the surrounding medium of each root was indirectly recorded and calculated as p.p.m. Almost all teeth of the experimental groups showed leakage of hydrogen peroxide compared to those of the control group. The radicular penetration of hydrogen peroxide was significantly higher in teeth of groups land Ill than in those of groups IV and V (P ≤ 0.001). In conclusion, the amount of hydrogen peroxide leakage depends, among other factors, on the form of sodium perborate used. The risk of post-bleaching cervical root resorption may be diminished by using sodium perborate tetrahydrate in conjunction with H2O. [ABSTRACT FROM AUTHOR]

Patients with cervical dentine exposures do not always complain of dentine hypersensitivity. The identification of morphological features connected to symptoms is important for both prevention and management of dentine hypersensitivity. The aim of the study was to determine the relationship between the dentine ultrastructure and clinical symptoms in patients with cervical dentine exposures. Replica models for a total of 28 teeth (from 10 patients) with cervical non caroius lesions and dentine exposures were obtained before and after acid etching. The replica models were studied blindly in the scanning electron microscope (SEM). 12 of these were classified clinically as hypersensitive and 16 as non-sensitive. Because of the morphological heterogeneity of all specimens. A grid was used to isolate smaller, more homogeneous areas. 120 (75 non-sensitive and 45 hypersensitive areas grid areas randomly selected from the 28 dentine surfaces were analyzed. The presence and morphology (amorphous or crystalline) of smear layers and the density and diameter of dentine tubules were recorded. The χ² test was used for statistical analysis. In unetched specimens, the surfaces classified as non-sensitive were frequently coated by an amorphous smear layer (88.0%) and occasionally by a crystalline smear layer (2.7%). Only a few and narrow tubules were observed (9.3%). On the other hand, the unetched specimens of the hypersensitive dentine exhibited less frequently (31.3%) an amorphous smear layer. The presence of crystalline smear layer 33.3%), many and wider patent tubules and, sometimes, loss of intertubular dentine manifested as grooves between tubules, were observed 35.6%). The differences were significant (p<.001). In hypersensitive dentine, the acid etching always removed the smear layer whereas removal in non-sensitive dentine was partial or absent. These morphological findings underline the role of smear layer in reducing permeability of dentine in patients with dentine sensitivity. [ABSTRACT FROM AUTHOR]