Evaluation of different mechanical cleaning protocols associated with 2.5% sodium hypochlorite in the removal of residues from the post space.

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

At-home bleaching with carbamide peroxide with concentrations below 10%: bleaching efficacy and permeability in the pulp chamber.

OBJECTIVES: To evaluate the bleaching efficacy and permeability of hydrogen peroxide (HP) in the pulp chamber of human teeth bleached with lower concentrations of carbamide peroxide gel (4%, 5% and 7% CP). MATERIALS AND METHODS: Bleaching gels with lower concentrations were formulated and a commercial standard gel, 10% CP, was used as a reference. Fifty-six human premolars were randomly divided into four groups. Applications of the bleaching gel were made for 3 h for 21 days. The bleaching efficacy was evaluated by digital spectrophotometry on 1, 7, 14 and 21 days, with analysis in the ∆Eab, ∆E00 and WID color spaces. The concentration of HP in the pulp chamber was measured in the same periods by UV-Vis spectrophotometry (µg/mL). Two-way repeated analysis of variance (ANOVA) examined bleaching efficacy and HP permeability, followed by Tukey's post-hoc test (α = 0.05). RESULTS: All groups showed significant color changes, with no statistical differences after the second and third week of bleaching (p > 0.05). The 'time' factor was statistically different (p < 0.05), increasing the bleaching efficacy throughout the treatment. The 4% CP group had lower HP levels in the pulp chamber (p < 0.05). CONCLUSIONS: The results seem promising, revealing that low concentration gels are as effective as 10% CP with the benefit of reducing the amount of HP in the pulp chamber. CLINICAL RELEVANCE: Low concentration 4% PC and 5% PC maintains bleaching efficacy, reduces the penetration of HP peroxide into the pulp chamber, and may reduce tooth sensitivity.

A novel mussel-inspired desensitizer based on radial mesoporous bioactive nanoglass for the treatment of dentin exposure: An in vitro study.

OBJECTIVES: The dentin exposure always leads to dentin hypersensitivity and the acid-resistant/abrasion-resistant stability of current therapeutic approaches remain unsatisfatory. Inspired by the excellent self-polymerization/adherence activity of mussels and the superior mineralization ability of bioactive glass, a novel radial mesoporous bioactive nanoglass coated with polydopamine (RMBG@PDA) was developed for prevention and management of dentin hypersensitivity. METHODS: Radial mesoporous bioactive nanoglass (RMBG) was synthesized by the sol-gel process combined with the cetylpyridine bromide template self-assembly technique. RMBG@PDA was synthesized by a self-polymerization process involving dopamine and RMBG in an alkaline environment. Then, the nanoscale morphology, chemical structure, crystalline phase and Zeta potential of RMBG and RMBG@PDA were characterized. Subsequently, the ion release ability, bioactivity, and cytotoxicity of RMBG and RMBG@PDA in vitro were investigated. Moreover, an in vitro experimental model of dentin hypersensitivity was constructed to evaluate the effectiveness of RMBG@PDA on dentinal tubule occlusion, including resistances against acid and abrasion. Finally, the Young's modulus and nanohardness of acid-etched dentin were also detected after RMBG@PDA treatment. RESULTS: RMBG@PDA showed a typical nanoscale morphology and noncrystalline structure. The use of RMBG@PDA on the dentin surface could effectively occlude dentinal tubules, reduce dentin permeability and achieve excellent acid- and abrasion-resistant stability. Furthermore, RMBG@PDA with excellent cytocompatibility held the capability to recover the Young's modulus and nanohardness of acid-etched dentin. CONCLUSION: The application of RMBG@PDA with superior dentin tubule occlusion ability and acid/abrasion-resistant stability can provide a therapeutic strategy for the prevention and the management of dentin hypersensitivity.

Evaluating color change and hydrogen peroxide penetration in human and bovine teeth through in-office bleaching procedures.

OBJECTIVE: Assess color alteration and hydrogen peroxide (HP) penetration in human and bovine teeth using various in-office bleaching protocols with different application times. MATERIALS AND METHODS: Thirty healthy human premolars and 30 healthy bovine incisors were divided into five groups and subjected to different bleaching protocols: 2 × 15 min, 1 × 30 min, 2 × 20 min, or 1 × 40 min, with a control group for each tooth type. All teeth were treated with 35% HP gel. Color alteration was measured using digital spectrophotometry before and 1 week after bleaching. HP concentration within the pulp was determined via UV-Vis spectrophotometry. Statistical analysis included one-way ANOVA, Tukey's, and Dunnett's tests (α = 0.05). RESULTS: All groups exhibited significant color alteration, with no statistically differences among them (p > 0.05). However, significant differences were observed when compared with their respective control groups (p < 0.05). HP penetration into the pulp was evident in all bleached teeth compared to the control groups (p < 0.05), with the 2 × 20 group showing the highest HP levels within the pulp cavity, irrespective of tooth type (p < 0.05). CONCLUSION: A simplified 1 × 30-min protocol can be recommended as it effectively maintains color alteration and HP penetration, irrespective of whether human or bovine teeth. CLINICAL SIGNIFICANCE: This study suggests that an in-office dental bleaching protocol using a 1 × 30-min session is recommended, as it ensures both effective color change and no increase in the amount of HP penetration.

Evaluation of hydrogen peroxide permeability, color change, and physical-chemical properties on the in-office dental bleaching with different mixing tip.

OBJECTIVE: This study aims to assess hydrogen peroxide (HP) penetration into the pulp chamber, color change (CC), physical-chemical properties, and material wastage (MW) and material used (MU) in mixing tips when using in-office bleaching gels with two different mixing tips. MATERIALS AND METHODS: Forty teeth were divided into five groups (n = 8) based on the bleaching gels used (Pola Office +37.5% [PO+] and Whiteness HP Automixx Plus 35% [AM+]) and the mixing tip types (T-Mixer and Helical). A negative control group was treated with ultra-purified water. HP concentration was measured using UV-Vis, and CC was evaluated with a digital spectrophotometer. Initial concentration, pH, and viscosity were measured through Titration, a Digital pH meter, and Rheometer, respectively. MW and MU were measured using a precise analytical balance. Statistical analysis included two-way ANOVA, Tukey's, and Dunnett's test (α = 0.05). RESULTS: A higher HP concentration was observed with PO+ with the Helical mixing tip in comparison with AM+ (p = 0.01). No significant differences in CC or MU were found for different mixing tips (p = 0.001). The T-mixer mixing tip resulted in significantly less MW (p < 0.00001) and improved mixture homogeneity and viscosity. CONCLUSIONS: Utilizing a T-mixer with self-mixing bleaching gels achieves comparable CC while reducing MW. Moreover, it decreases HP penetration when using PO+. CLINICAL SIGNIFICANCE: For the application of a self-mixing in-office bleaching gel, a T-mixer mixing tip should be recommended, as it reduces the penetration of hydrogen peroxide into the pulp chamber when using PO+, while also minimizing gel wastage.

Novel resin-based material containing ß-tricalcium phosphate nanoparticles for the reduction of dentin permeability.

OBJECTIVES: To synthesize and characterize a novel dentin adhesive containing Beta-Tricalcium Phosphate (ß-TCP) nanoparticles and test its ability to reduce dentin permeability (dP). METHODS: Experimental adhesives were prepared by mixing Bis-GMA, TEGDMA, HEMA (50/25/25 wt.%), photo-initiators, and inhibitors. The following groups were tested: Experimental adhesives without ß-TCP (Exp.); with 10 wt.% ß-TCP (Exp.10 wt.% ß-TCP); with 15 wt.% ß-TCP (Exp.15 wt.% ß-TCP), Scotchbond Multi-Purpose (SBMP) and Clearfil SE Protect Bond (CFPB). Degree of conversion (DC%, 10 and 20 s); Flexural Strength (FS), Knoop Hardness (KHN), and Cell Viability (OD%) tests were performed. dP was evaluated by hydraulic conductance, using human dentin disks (n=12), at three-time intervals: post-EDTA (T0); post-treatment (T1); and post-erosion/abrasion cycling (T2). Data were statistically analyzed (α=0.05). RESULTS: For all groups, exposure time for 20 s presented a higher DC% than for 10 s. For FS, filled adhesives did not differ from unfilled and from CFPB. Experimental adhesives did not differ among them and showed lower KHN than the commercial products. Cell viability did not differ among adhesives, except Exp. 15 wt.%, which showed lower OD% than Exp., Exp. 10% and, CFPB. For dP, only Exp.10 and 15 wt.% ß-TCP did not present difference between the times T1 and T2. After cycling, Exp.10 wt.% ß-TCP presented lower permeability than Exp. and CFPB. CONCLUSIONS: The incorporation of 10 wt.% ß-TCP nanoparticles into the resin-based dental material did not affect its mechanical properties and biocompatibility, and promoted the greatest reduction in dentin permeability, sustaining this effect under erosive/abrasive challenges. CLINICAL SIGNIFICANCE: A novel resin-based dental material containing ß-TCP nanoparticles was able to reduce dentin permeability, maintaining its efficacy after erosive/abrasive challenges. The synthesized material did not affect dental pulp cell viability and might be promising for other conditions that require dental remineralization, such as tooth wear and dental caries.

Repair potential of biodentine in vital pulp therapies in mature permanent teeth: a narrative review / POTENCIAL REPARADOR DEL BIODENTINE EN TERAPIAS PULPARES VITALES EN DIENTES PERMANENTES MADUROS: UNA REVISIÓN NARRATIVA

Vital pulp therapy in dentistry seeks to treat lesions in the dental pulp caused by cavities, trauma or iatrogenic procedures. Its objective is to maintain the vitality and function of the pulp, restoring the continuity of the dentin, known as the dentinal bridge. The dentinal bridge is crucial for injury repair and promotes pulp healing. Stem cells from the dental pulp can differentiate into odontoblasts, responsible for the formation of reparative dentin. To achieve success in vital pulp therapy, factors such as the appropriate choice of biocompatible biomaterials that prevent bacterial infiltration and inflammatory reactions, as well as the response of the pulp to injury, must be considered. An emerging material is Biodentine, a dentin substitute based on calcium silicate that induces the formation of dentin bridges and has demonstrated effectiveness in the repair of the dentine-pulp complex. It acts through specific molecular pathways by inducing the differentiation of dental pulp stem cells. This narrative review aims to describe the restorative potential of Biodentine in vital pulp therapies in mature permanent teeth. Its ability to reduce pulp inflammation, differentiate stem cells, the mechanism of action for the formation of tertiary dentin and characteristics of the dentinal bridge were evaluated. The results indicate that Biodentine has anti-inflammatory properties and stimulates dentin regeneration, influencing cell differentiation and mineralization. To conclude, Biodentine shows broad reparative potential in vital pulp therapies in mature permanent teeth, reduction of pulp inflammation, great cellular bioactivity, differentiation, and high dentin quality.

La terapia pulpar vital en odontología busca tratar lesiones en la pulpa dental causadas por caries, traumatismos o procedimientos iatrogénicos. Su objetivo es mantener la vitalidad y función de la pulpa, restaurando la continuidad de la dentina, conocida como puente dentinario. El puente dentinario es crucial para la reparación de lesiones y promueve la cicatrización de la pulpa. Las células madre de la pulpa dental pueden diferenciarse en odontoblastos, responsables de la formación de dentina reparadora. Para lograr el éxito en la terapia pulpar vital, se deben considerar factores como la elección adecuada de biomateriales biocompatibles que prevengan la infiltración bacteriana y reacciones inflamatorias, así como la respuesta de la pulpa a la lesión. Un material emergente es el Biodentine, un sustituto de dentina basado en silicato de calcio que induce la formación de puentes de dentina y ha demostrado eficacia en la reparación del complejo dentino-pulpar. Actúa mediante vías moleculares específicas al inducir la diferenciación de células madre de la pulpa dental. Esta revisión narrativa tiene como objetivo describir el potencial reparador del Biodentine en terapias pulpares vitales en dientes permanentes maduros. Se evaluó su capacidad para reducir la inflamación pulpar, como de diferenciar células madre, el mecanismo de acción para la formación de dentina terciaria y características del puente dentinario. Los resultados indican que Biodentine tiene propiedades antiinflamatorias y estimula la regeneración dentinaria, influenciando la diferenciación celular y la mineralización. Para concluir, Biodentine muestra un amplio potencial reparador en terapias pulpares vitales en dientes permanentes maduros, reducción de inflamación pulpar, gran bioactividad celular, diferenciación, y alta calidad de dentina.

A terapia pulpar vital em odontologia busca tratar lesões na polpa dentária causadas por cáries, traumas ou procedimentos iatrogênicos. Seu objetivo é manter a vitalidade e função da polpa, restaurando a continuidade da dentina, conhecida como ponte dentinária. A ponte dentinária é crucial para a reparação de lesões e promove a cicatrização pulpar. As células-tronco da polpa dentária podem se diferenciar em odontoblastos, responsáveis ​​pela formação da dentina reparadora. Para obter sucesso na terapia pulpar vital, devem ser considerados fatores como a escolha adequada de biomateriais biocompatíveis que previnam infiltração bacteriana e reações inflamatórias, bem como a resposta da polpa à lesão. Um material emergente é o Biodentine, um substituto dentinário à base de silicato de cálcio que induz a formação de pontes dentinárias e tem demonstrado eficácia na reparação do complexo dentina-polpa. Atua através de vias moleculares específicas, induzindo a diferenciação de células-tronco da polpa dentária. Esta revisão narrativa tem como objetivo descrever o potencial restaurador do Biodentine em terapias pulpares vitais em dentes permanentes maduros. Foram avaliadas sua capacidade de reduzir a inflamação pulpar, diferenciar células-tronco, mecanismo de ação para formação da dentina terciária e características da ponte dentinária. Os resultados indicam que Biodentine possui propriedades anti-inflamatórias e estimula a regeneração da dentina, influenciando a diferenciação e mineralização celular. Concluindo, Biodentine apresenta amplo potencial reparador em terapias pulpares vitais em dentes permanentes maduros, redução da inflamação pulpar, grande bioatividade celular, diferenciação e alta qualidade dentinária.

In vitro dentin permeability and tubule occlusion of experimental in-office desensitizing materials.

OBJECTIVES: This study investigates the dentin permeability (by hydraulic conductance) and tubule occlusion (by confocal and scanning electron microscopies) of in-office desensitizing materials. MATERIALS AND METHODS: Bovine dentin blocks were immersed in EDTA to open dentinal tubules. Placebo varnish (PLA), fluoride varnish (FLU), NaF 5% + 5% nanoparticulate sodium trimetaphosphate varnish (TMP), universal adhesive system (SBU), S-PRG filler varnish (SPRG), Biosilicate (BIOS), and amelotin (AMTN) solution were the materials tested. After application, the specimens underwent an erosive-abrasive challenge. Dentin permeability was evaluated at T0 (initial), T1 (after treatment), and T2 (after challenge). Confocal and scanning electron microscopy (SEM) were used to evaluate, respectively, length and number of dentinal tubule occlusions and opened dentinal tubules, after challenge. Permeability and SEM data were analyzed by two-way repeated measures ANOVA and Tukey's tests. Confocal data were analyzed by one-way ANOVA, Tukey's test, and Kruskal-Wallis and Dunn's tests. Spearman and Pearson's correlation tests were also used. Significance level was set at 5%. RESULTS: At T1, the AMTN group showed the lowest permeability value, following the increasing order at T2: AMTN = SBU < BIOS = SPRG < TMP < FLU < PLA. The SBU group had the highest value of occluded dentinal tubule length. The AMTN group presented more occluded dentinal tubules compared to PLA and FLU. AMTN and SBU had the lowest values of opened dentin tubules. Results showed a negative correlation between the analyses. CONCLUSION: The SBU and AMTN solution were more effective in reducing dentin permeability by occluding dentin tubules. CLINICAL RELEVANCE: All materials reduced permeability after challenge, except fluoride varnish.

Dentin permeability after pretreatment with titanium tetrafluoride and self-etching or universal adhesive systems

Aim: To evaluate dentin permeability after pretreatment with 2.5% aqueous solution of titanium tetrafluoride (TiF4), followed by a self-etching universal adhesive system. Methods: Forty dentin discs (1.5 mm thick) were randomly divided into groups according to the application or non-application of a pretreatment, and the type of adhesive system to be tested (two-step self-etching/ Clearfil SE Bond/ Kuraray Medical, or universal adhesive system/ Single Bond Universal/ 3M ESPE). Both sides of the discs were conditioned with 37% phosphoric acid to remove the smear layer. The first hydraulic conductivity measurement (L1) was performed in a permeability machine, under 5 PSI pressure. The samples were sanded again to form a standardized smear layer. The teeth designated for pre-treatment with TiF4 received the TiF4 solutions applied actively for 60 seconds, and the adhesive systems were applied according to the manufacturer's instructions. Then, a new hydraulic conductivity measurement (L2) was performed for the purpose of calculating the hydraulic conductance at a later time, considering the water viscosity and the thickness of the specimen. The percentage (L) of dentin permeability after application of the adhesive system was obtained (L (%) = [(L1-L2) x100] / L1). The Mann-Whitney non-parametric test was applied. Results: There was no difference between the two adhesive systems, or between the groups with or without pretreatment, as regards dentin permeability (p>0.05). Conclusion: Pretreatment with 2.5% TiF4 did not influence dentin permeability, irrespective of the adhesive system used

Iontophoresis effects of two-step self-etch and total-etch systems on dentin permeability and sealing of composite restoration under simulated pulpal pressure.

BACKGROUND: Studies demonstrated the bond strength enhancement and the decrease in degradation of the adhesive interface after applying either self-etch adhesives or two-step, etch-and-rinse adhesives under an electric field. However, the presence of dentinal fluid driven by the pulpal pressure in vivo is a profounding factor affecting both the sealing ability and bond strength of adhesives. This study aimed to evaluate the effect of three-step etch-and-rinse and two-step self-etch adhesives when applied with iontophoresis under simulated pulpal pressure on the permeability of dentin, resin infiltration, and the sealing ability of resin composite. METHODS: The experiments were done on 32 recently extracted premolars, randomly assigned into four groups (n = 8) according to two adhesive systems (SBMP and SE), applied following the manufacturer's instructions (control) for two groups or with iontophoresis for the others (SBMPi and SEi). For the iontophoresis, the anodal current was applied at 75 µA for 20 s through the cavity electrode during the bond. The fluid flow rate of dentin was recorded after cavity preparation (smear-layer-covered dentin; T1), bonding (T2), and composite restoration (T3) during the maintained pulpal pressure of 20 mm Hg. The flow rates were expressed as a percentage relative to the initial smear-layer-covered value for each specimen. Results were analyzed using repeated measures ANOVA. Scanning electron microscopy (SEM) was performed to observe the resin/dentin interface. RESULTS: There were no significant increases in the mean flow rates from T1 to T3 in the SBMP (P = 0.355), while these changes in the SE were significant between T1 (100%) and T2 (166.77%) and T1 and T3 (221.16%) (P = 0.002; one-way RM ANOVA; Holm-Sidak test). For the iontophoresis groups, the mean flow rates decreased significantly from T1 to T2 and T1 to T3 of both SBMPi (T2 = 86.43, and T3 = 79.53; P < 0.001) and SEi groups (T2 = 87.96, and T3 = 81.48; P = 0.004). The iontophoresis of both adhesives produced the optimal resin infiltration with improved quality of the hybrid layer and resin tags. CONCLUSIONS: SBMP bonded with or without iontophoresis performed better sealing ability than SE under the same condition. Both adhesives applied with anodal iontophoresis significantly decreased the dentin permeability, contributing to the improved resin infiltration.

Bonding strategy of a universal adhesive system containing chitosan: influence on dentin permeability, and effect on adhesive layer micromorphology / Estratégia de união de um sistema adesivo universal contendo quitosana: influência na permeabilidade dentinária e efeito na micromorfologia da camada do adesivo

ABSTRACT Aim: This study evaluated the influence of chitosan added to a universal adhesive system used in totaletch (TE) or self-etch (SE) mode on dentin permeability, and on the micromorphology of the adhesive layer. Materials and Method: Dentin discs were obtained from human third molars and randomly distributed according to bonding strategy (TE or SE), and to whether or not 1% chitosan (C) was added to a universal adhesive system (Single Bond Universal/3M ESPE), to create the following groups (n=10): TE, TEC, SE, and SEC. Dentin permeability was measured at baseline and after application of dentin treatments. The surface of the adhesive layer (AL) and the dentin adjacent to the AL were examined under a scanning electron microscope. Results: There were no significant differences in permeability percentage between the groups with and without C (TE and SE versus TEC and SEC) (p>0.05; Mann Whitney test). Dentin permeability was lower when the adhesive system was applied in the SE mode, regardless of the addition of C. The micromorphology of the AL surface showed irregularities, and a greater degree of porosity, when the adhesive system was applied in the SE mode, regardless of chitosan addition. There was a greater depth of penetration of the adhesives into the dentin adjacent to the AL in both the TE and TEC groups. Chitosan added to the adhesive system did not influence dentin permeability. Conclusions: The self-etch strategy led to lower dentin permeability, and to more irregularities on the surface of the adhesive layer.

RESUMO Objetivo: Este estudo avaliou a influência da quitosana adicionada a um sistema adesivo universal usado no modo total-etch (TE) ou self-etch (SE) na permeabilidade dentinária e na micromorfologia da camada adesiva. Materiais e método: Discos de dentina foram obtidos de terceiros molares humanos e distribuídos aleatoriamente de acordo com a estratégia de união (TE ou SE), e para incorporação ou não de quitosana a 1% (Q) em um sistema adesivo universal (Single Bond Universal/3M ESPE), para obter os seguintes grupos (n=10): TE, TEQ, SE e SEQ. A permeabilidade da dentina foi medida no início e após a aplicação dos tratamentos de dentina. A superfície da camada adesiva (CA) e a dentina adjacente à CA foram examinadas em microscópio eletrônico de varredura. Resultados: Não houve diferenças significativas no percentual de permeabilidade entre os grupos com e sem Q (TE e SE versus TEQ e SEQ) (p>0,05; teste de Mann Whitney). Houve um menor percentual de permeabilidade dentinária quando o sistema adesivo foi aplicado no modo SE, independentemente da incorporação de Q. A micromorfologia da superfície da CA apresentou irregularidades e maior grau de porosidade quando o sistema adesivo foi aplicado no modo SE, independentemente da adição de Q. Houve maior profundidade de penetração dos adesivos na dentina adjacente à CA nos grupos TE e TEQ. A quitosana adicionada ao sistema adesivo não influenciou a permeabilidade dentinária. Conclusões: A estratégia autocondicionante levo

Effect of different toothpastes on permeability and roughness of eroded dentin / Efeito de diferentes cremes dentais na permeabilidade e rugosidade da dentina erodida

ABSTRACT Dentin hypersensitivity (DH) is characterized by rapid, acute pain arising from exposed dental tubules. Aim: the aim of this study was to evaluate the roughness, tubule occlusion, and permeability of eroded dentin brushed with different toothpastes. Materials and Method: ninety bovine teeth were cut into blocks. Thirty hemifaces were protected with varnish and the other sixty were submitted to permeability tests. Specimens were divided into groups according to the dentifrices: without fluoride (WF), sodium fluoride (NaF), and stannous fluoride (SnF2). The blocks were subjected to a 5-day erosive-abrasive protocol. Surface roughness and dentinal tubule occlusion (n=10) were assessed for both control and test hemifaces of the same sample along with permeability analysis (n=20). Two-way RM ANOVA and Tukey's post-hoc test were performed (p≤0.05). Results: NaF and SnF2 presented higher roughness than WF. The number of open tubules was higher in WF. Permeability was higher in SnF2, but there was no significant difference between WF and NaF. Conclusions: both fluoride toothpastes occluded dentinal tubules and increased roughness. NaF toothpaste promoted greater decrease in dentin permeability.

RESUMO A hipersensibilidade dentinária (HD) é caracterizada por dor rápida e aguda decorrente de túbulos dentais expostos. Objetivo: este estudo teve como objetivo avaliar a rugosidade, oclusão tubular e permeabilidade da dentina erodida escovada com diferentes dentifrícios. Materiais e Método: noventa dentes bovinos foram seccionados em blocos. Trinta hemifaces foram protegidas com verniz e outras sessenta foram submetidas à permeabilidade. Os espécimes foram divididos em grupos de acordo com os dentifrícios: sem flúor (SF), fluoreto de sódio (NaF) e fluoreto estanoso (SnF2). Em seguida, os blocos foram submetidos a um protocolo erosivo-abrasivo de 5 dias. A rugosidade da superfície e a oclusão do túbulo dentinário (n = 10) foram avaliadas para ambas as hemifaces de controle e teste da mesma amostra, também realizou-se a análise de permeabilidade (n = 20). Two-way RM ANOVA e pós-teste de Tukey foram realizados (p≤0,05). Resultados: NaF e SnF2 apresentaram rugosidade superior ao SF. O número de túbulos abertos foi maior em SF. Não encontramos diferenças significativas entre SF e NaF em relação à permeabilidade; entretanto, SnF2 apresentou maior permeabilidade. Conclusão: ambos os dentifrícios fluoretados foram capazes de ocluir os túbulos dentinários e aumentar a rugosidade. No entanto, o dentifrício NaF promoveu uma maior diminuição da permeabilidade dentinária.

Comparative Study on the Efficacy of OliNano Seal and Curodont D'Senz in the Treatment of Dentin Hypersensitivity (Clinical Trial and In Vitro Study).

Purpose: The present study was carried out to assess and compare the efficacy of OliNano Seal (OS) and Curodont D'Senz (CS) in the treatment of dentin hypersensitivity (DH) and the reduction of dentin permeability. Materials and Methods: The current study was a single-blinded, clinical trial and in vitro study using OS and CS in the treatment of DH. A total of 72 hypersensitive teeth were selected from 18 patients and randomly divided into two groups. Prior to the desensitizing agent's application (the baseline), as well as immediately, 2 weeks, 4 weeks, and 3 months afterward, the evaluated materials were applied. Patients were instructed to use the visual analogue scale (VAS) to score their perception of tactile, air, and cold stimuli (VAS). In total, 90 samples were used for the evaluation, and they were randomly divided into two main groups: group A1, which had the smear layer fully removed, and group A2, which had the smear layer partially removed. According to the desensitizing agent used, each group was divided into three subgroups: OS, CS, and the control group that was left untreated. The results of the dentin permeability test were analyzed using the analysis of variance test, whereas the pain scores were analyzed using the Mann-Whitney test. Results: The study showed that there was a high statistically significant difference between pain scores prior to and after the application of both tested desensitizing agents. Permeability results revealed a high statistically significant difference between the study groups, with the lowest statistically significant mean depth of dye penetration found with OS-treated samples. Conclusion: OS and CS were both effective in the treatment of DH and the reduction of dentin permeability, with OS being more effective within 1 week and sustained up to 3 months.

A 58S bioactive glass for dentin hypersensitivity and erosive tooth wear: An in vitro study.

OBJECTIVES: To assess the effect of an experimental 58S bioactive glass on dentin permeability (dP) and erosive tooth wear (dentin surface loss - dSL). METHODS: 58S bioactive glass was synthetized using a sol-gel methodology, following by lyophilization and calcination, then mixed with phosphoric acid to obtain a paste (BGP). Forty-eight dentin disks (1 mm-thick) were used for dP, and 48 dentin slabs (3 mm × 3 mm) for dSL, which were assessed at three time intervals: post-EDTA (5 min in 17% EDTA solution); post-treatment (C: distilled water; BGP: experimental bioactive glass paste; NP: Nupro prophylaxis paste; CXT: Clinpro XT varnish); and post-erosive/abrasive cycling. Data were statistically analyzed (α=0.05). RESULTS: For dP and dSL, Groups did not differ significantly post-EDTA (p>0.05). Post-treatment, all groups showed lower dP than C (p<0.05), without differing significantly among them. For the dSL analysis, Groups C, BGP and NP did not differ significantly, showing lower values than CXT (p<0.05). Post-cycling, C continued to show the highest dP (p<0.05). Specimens from Group CXT had the lowest dP and did not differ from NP (p=0.86) which did not differ from BGP (p=0.193). For C and BGP, dP value was higher post-cycling than post-treatment (p<0.05). For NP and CXT, these experimental times did not differ (p>0.05). Post-cycling, dSL for C, BGP and NP did not differ significantly; values were higher than those for CXT (p<0.05). CONCLUSIONS: BGP reduced dP after application, with a reduced effect after cycling. Nonetheless, it was not able to protect dentin against erosive tooth wear. CLINICAL SIGNIFICANCE: Minimizing dentin hypersensitivity is a challenge in the field of dentistry. The development of alternative products with potential to obliterate dentinal tubules and provide resistance to chemical/mechanical stimuli is, thus, highly desirable. We have proposed a material able to reduce dentin permeability, which has emerged as a promising alternative for this purpose.

Effectiveness and cytotoxicity of two desensitizing agents: a dentin permeability measurement and dentin barrier testing in vitro study.

BACKGROUND: When evaluating the efficacy and safety of various desensitizing products in vitro, their mechanism of action and clinical utility should be considered during test model selection. This study aimed to evaluate the effects of two desensitizers, an in-office use material and an at-home use material, on dentin specimen permeability, and their dentin barrier cytotoxicity with appropriate test models. METHODS: Two materials, GLUMA desensitizer (GLU) containing glutaraldehyde and remineralizing and desensitizing gel (RD) containing sodium fluoride and fumed silica, were selected. Human dentin specimens were divided into three groups (n = 6): in groups 1 and 2, GLU was applied, and in group 3, RD was applied and immersed in artificial saliva (AS) for 24 h. Dentin specimen permeability before and after each treatment/post-treatment was measured using a hydraulic device under a pressure of 20 cm H2O. The perfusion fluid was deionized water, except in group 2 where 2% bovine serum albumin (BSA) was used. The representative specimens before and after treatment from each group were investigated using scanning electron microscopy. To measure cytotoxicity, test materials were applied to the occlusal surfaces of human dentin disks under which three-dimensional cell scaffolds were placed. After 24-h contact within the test device, cell viability was measured via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. RESULTS: GLU significantly reduced the dentin permeability and occluded the dentinal tubules when 2% BSA was used as perfusion fluid. RD significantly reduced dentin permeability and occluded the tubules, but permeability rebounded after AS immersion. GLU significantly decreased cell viability, but RD was non-cytotoxic. CONCLUSIONS: In vitro GLU application induced effective dentinal tubule occlusion only following the introduction of simulated dentinal fluid. RD provided effective tubule occlusion, but its full remineralization potential was not realized after a short period of immersion in AS. GLU may harm the pulp, whereas RD is sufficiently biocompatible.

Resin-based materials to control human dentin permeability under erosive conditions in vitro: A hydraulic conductance, confocal microscopy and FTIR study.

OBJECTIVES: To characterize the behavior of three different polymeric agents before and after an erosive challenge on dentin permeability, to analyze their degradation in both conditions, and to analyze their degree of conversion (DC). METHODS: The permeability of human dentin disks (1.0 ± 0.2 mm) was measured with smear layer, after its removal, after treatment (LpTreat) with Gluma Desensitizer, PRG Barrier Coat (PBC) or Icon infiltrant (n = 11/group) and after exposure to citric acid (LpEro) (6%, pH 2.1, 1 min). The specimens were analyzed under a Laser Scanning Confocal Microscope (n = 2/group) and the products' DC were calculated. Data were subjected to 2-way repeated measures ANOVA and post-hoc Bonferroni (permeability analysis), to paired t-test (for specimens treated with Icon) and to t-test (DC analysis) (α < 0.05). RESULTS: Icon showed the lowest LpTreat and LpEro values, while PBC and Gluma did not differ from each other under these conditions. Icon and PBC showed LpEro similar to a dentin with smear layer. Under the Laser Scanning Confocal Microscope, more deposits were noticeable on dentin after treating with PBC. Gluma presented the deepest penetration in dentin. The DC of PBC was the highest. SIGNIFICANCE: Icon caused the highest reduction on permeability values, followed by PBC and Gluma. PBC generated more deposits covering dentin and seemed to be more efficient after an erosive challenge. The association of a polymeric resin with inorganic ion-releasing fillers seem to be a great strategy to manage dentin hypersensitivity under erosive conditions.

Effect of obturation technique on penetration of calcium silicate-based sealer into dentinal tubules after endodontic retreatment of mandibular premolars.

OBJECTIVE: Confocal laser scanning microscopy (CLSM) was used to investigate the penetration of endodontic sealers into the dentinal tubules after retreatment using two different obturation techniques. MATERIALS AND METHODS: Thirty mandibular premolars were prepared up to instrument F3 (ProTaper Universal, Dentsply) and filled with Endofill using the single cone technique. The canals were retreated using Mtwo instruments. Reobturation was performed with the Bio-C sealer mixed with a fluorophore dye (Fluo-3) using either the lateral condensation technique (group LC) or the single cone technique (group SC) (n = 15). Teeth were sectioned 2, 4, and 6 mm from the apex and analyzed with CLSM to assess the penetration of the sealer into the canal perimeter and the maximum depth of penetration of the sealer into the dentinal tubules. Data were analyzed using ANOVA and the Student-t and Holm-Sidak tests. RESULTS: In the apical segment, the penetrated perimeter was significantly higher in the LC group than in the SC group (p < 0.05); no significant difference was found in the middle and cervical segments (p > 0.05). In terms of penetration depth, no significant differences were found for any of the segments studied (p > 0.05). CONCLUSION: The LC technique promoted a higher percentage of canal circumference penetrated by the sealer than the SC technique in the apical segment after endodontic retreatment. CLINICAL RELEVANCE: CLSM demonstrated that the LC technique promoted a higher percentage of canal perimeter penetrated by the Bio-C sealer than the SC technique in the apical segment of mandibular premolars after retreatment.

Experimental pastes containing niobophosphate and 45S5 bioactive glasses for treatment of dentin hypersensitivity: dentin permeability and tubule obliteration.

OBJECTIVES: This study tested the ability of bioactive pastes containing niobophosphate and 45S5 glasses to reduce dentin permeability and to obliterate dentinal tubules, as a mean of reducing human dentin hypersensitivity. MATERIALS AND METHODS: Experimental pastes with concentrations of 10, 20, and 30 wt% of two bioactive glasses (45S5 or niobophosphate [NbG]) were formulated. A paste without bioactive glass (placebo) and a commercial paste (Nano P, FGM) were used as controls. Forty dentin disc specimens were obtained from caries-free extracted third human molars and divided in 8 groups (n = 5). Percentage of permeability (%Lp) was assessed in a dental permeability machine considering hydraulic conductance, immediately after pastes application and at day 7, day 14, and day 21. The precipitates formed on the surface of the dentin discs (and dentinal tubules) were analyzed by SEM/EDS and micro-Raman spectra. Data of dentin permeability (%) 2-way repeated-measures (ANOVA) and Holm-Sidak post-tests (α = 0.05). Dentinal tubule obliteration was visually (and elemental) evaluated and descriptively reported. RESULTS: The experimental bioactive glass pastes containing NbG and 45S5, regardless of the concentration, reduced dentin permeability in comparison with pastes without bioactive glasses (P < 0.05). The formulated placebo and commercial paste did not reduce permeability over time (P < 0.05). SEM/EDS and micro-Raman analyses showed that both type of bioactive pastes (NbG or 45S5-based) presented mineral precipitates obliterating the dentinal tubules at day 21. NbG seems to offer a better initial effect than 45S5, while at 21 days there is no difference between both glasses. CONCLUSION: Experimental bioactive pastes containing NbG and 45S5 (at concentrations of 10%, 20%, or 30%) have potential to reduce dentin permeability (over time) in comparison with pastes without bioactive glasses; and this occurs on behalf of obliteration of dentinal tubules by microparticle and precipitate formation. CLINICAL RELEVANCE: Bioactive pastes containing NbG and 45S5 may benefit patients presenting dentin hypersensitivity, because these pastes can start acting fast after application and maintain their action up to 21 days.

Physicochemical properties and penetration into dentinal tubules of calcium hypochlorite with surfactants

Abstract The aim was to assess the physicochemical properties and the penetration into dentinal tubules of calcium hypochlorite solution [Ca(OCl)2], with or without surfactants. The surfactants benzalkonium chloride, cetrimide, Tween 80 and Triton X-100 were mixed at different concentrations with sodium hypochlorite solution (NaOCl), Ca(OCl)2 and distilled water (control). Once the critical micellar concentration (CMC) of the surfactants in Ca(OCl)2 and NaOCl was determined, pH, free chlorine, surface tension and free calcium ions were evaluated. The penetration into dentinal tubules of NaOCl and Ca(OCl)2, with or without benzalkonium chloride and Triton X-100 [surfactants that promoted the lowest surface tension of Ca(OCl)2], was assessed using human premolars stained with crystal violet. The statistical tests were one-way ANOVA and Tukey's post-test, Kruskal-Wallis and Dunn's post-test, two-way ANOVA and Bonferroni's post-test, and t-test; depending on the assay. The addition of surfactants reduced the surface tension of NaOCl and Ca(OCl)2, and did not alter the pH or the free available chlorine of either solution. The addition of all surfactants increased the availability of free calcium ions in Ca(OCl)2, especially benzalkonium chloride. Ca(OCl)2 exhibited lower penetration into dentinal tubules than NaOCl, and the addition of surfactants did not improve the penetration of Ca(OCl)2, but did increase the penetration of NaOCl. It can be concluded that the addition of surfactants to Ca(OCl)2 did not increase the penetration into dentinal tubules, but it did promote lower surface tension, without changing the pH or free available chlorine values, and higher availability of free calcium ions in Ca(OCl)2.

Resumo O objetivo foi avaliar as propriedades físico-químicas e a penetrabilidade nos túbulos dentinários da solução de hipoclorito de cálcio [Ca(OCl)2], com ou sem surfactantes. Os surfactantes cloreto de benzalcônio, cetrimida, Tween 80 e Triton X-100 foram misturados em diferentes concentrações com a solução de hipoclorito de sódio (NaOCl), Ca(OCl)2 e água destilada (controle). Uma vez determinada a concentração micelar crítica (CMC) dos surfactantes em Ca(OCl)2 e NaOCl, foram avaliados o pH, cloro livre, tensão superficial e íons de cálcio livre. A penetrabilidade nos túbulos dentinários de NaOCl e Ca(OCl)2, com ou sem cloreto de benzalcônio e Triton X-100 [surfactantes que promoveram a menor tensão superficial de [Ca(OCl)2] foi avaliada utilizando pré-molares humanos corados com cristal violeta. Os testes estatísticos foram ANOVA de uma via e pós-teste de Tukey, Kruskal-Wallis e pós-teste de Dunn, ANOVA de duas vias e pós-teste de Bonferroni, e teste t; dependendo do ensaio. A adição de surfactantes reduziu a tensão superficial do NaOCl e Ca(OCl)2, e não alterou o pH ou cloro livre das soluções. A adição de todos os surfactantes aumentou a disponibilidade de íons de cálcio livre de Ca(OCl)2, principalmente o cloreto de benzalcônio. Ca(OCl)2 apresentou menor penetrabilidade nos túbulos dentinários do que NaOCl, e a adição de surfactantes não aumentou a penetrabilidade de Ca(OCl)2, mas aumentou a penetrabilidade de NaOCl. Pode-se concluir que a adição de surfactantes no Ca(OCl)2 não aumentou a penetrabilidade nos túbulos dentinários, mas promoveu menor tensão superficial, sem alterar os valores de pH ou cloro livre, e maior disponibilidade de íons de cálcio livre em Ca(OCl)2.

Bonding strategy of a universal adhesive system containing chitosan: influence on dentin permeability, and effect on adhesive layer micromorphology.

AIM: This study evaluated the influence of chitosan added to a universal adhesive system used in totaletch (TE) or self-etch (SE) mode on dentin permeability, and on the micromorphology of the adhesive layer. MATERIALS AND METHOD: Dentin discs were obtained from human third molars and randomly distributed according to bonding strategy (TE or SE), and to whether or not 1% chitosan (C) was added to a universal adhesive system (Single Bond Universal/3M ESPE), to create the following groups (n=10): TE, TEC, SE, and SEC. Dentin permeability was measured at baseline and after application of dentin treatments. The surface of the adhesive layer (AL) and the dentin adjacent to the AL were examined under a scanning electron microscope. RESULTS: There were no significant differences in permeability percentage between the groups with and without C (TE and SE versus TEC and SEC) (p>0.05; Mann Whitney test). Dentin permeability was lower when the adhesive system was applied in the SE mode, regardless of the addition of C. The micromorphology of the AL surface showed irregularities, and a greater degree of porosity, when the adhesive system was applied in the SE mode, regardless of chitosan addition. There was a greater depth of penetration of the adhesives into the dentin adjacent to the AL in both the TE and TEC groups. Chitosan added to the adhesive system did not influence dentin permeability. CONCLUSIONS: The self-etch strategy led to lower dentin permeability, and to more irregularities on the surface of the adhesive layer.

OBJETIVO: Este estudo avaliou a influência da quitosana adicionada a um sistema adesivo universal usado no modo total-etch (TE) ou self-etch (SE) na permeabilidade dentinária e na micromorfologia da camada adesiva. Materiais e método: Discos de dentina foram obtidos de terceiros molares humanos e distribuídos aleatoriamente de acordo com a estratégia de união (TE ou SE), e para incorporação ou não de quitosana a 1% (Q) em um sistema adesivo universal (Single Bond Universal/3M ESPE), para obter os seguintes grupos (n=10): TE, TEQ, SE e SEQ. A permeabilidade da dentina foi medida no início e após a aplicação dos tratamentos de dentina. A superfície da camada adesiva (CA) e a dentina adjacente à CA foram examinadas em microscópio eletrônico de varredura. RESULTADOS: Não houve diferenças significativas no percentual de permeabilidade entre os grupos com e sem Q (TE e SE versus TEQ e SEQ) (p>0,05; teste de Mann Whitney). Houve um menor percentual de permeabilidade dentinária quando o sistema adesivo foi aplicado no modo SE, independentemente da incorporação de Q. A micromorfologia da superfície da CA apresentou irregularidades e maior grau de porosidade quando o sistema adesivo foi aplicado no modo SE, independentemente da adição de Q. Houve maior profundidade de penetração dos adesivos na dentina adjacente à CA nos grupos TE e TEQ. A quitosana adicionada ao sistema adesivo não influenciou a permeabilidade dentinária. Conclusões: A estratégia autocondicionante levou a uma menor permeabilidade dentinária e a mais irregularidades na superfície da camada adesiva.