Dentinal Tubule Occlusion Research Articles

A monetite/amorphous silica complex for long-term dentine hypersensitivity treatment through the acid stability and mineralization promoting effect of silica.

Dentine hypersensitivity (DH) is often related to the exposure of dentin tubules. Mineral particles, such as hydroxyapatite and bioactive glass, can provide calcium and phosphate ions to temporarily block dentin tubules via the biomineralization process, serving as feasible alternatives for DH treatment. However, due to the acidic microenvironment caused by dietary acids, these particles are easily eroded and dissolved, making it difficult to achieve efficient dentin tubule occlusion. Given the significant stability of silica in dietary acids and its excellent ability to bond with calcium and phosphate ions to form mineralized hydroxyapatite, we proposed to develop a micron-sized monetite/amorphous silica complex (MMSi) hydrosol to effectively seal the exposed dentin tubules. In this study, we hypothesized that the MMSi hydrosol could tolerate acid erosion and concurrently provide active sites for the calcium and phosphate ions to promote biomineralization in comparison to a micron-sized monetite (MM) hydrosol. Hence, the composition and microstructure including the surface morphology, silica content and phase composition of MMSi were investigated to verify the presence of silica. The results of the ion release and in vitro biomineralization process indicated that silica did not hinder the calcium and phosphate ion release and the formation of hydroxyapatite via the biomineralization process. The acid-resistant test suggested that the MMSi hydrosol exhibited a significantly slower corrosion rate than the MM hydrosol when treated with citric acid. Notably, the silica in the MMSi hydrosol retained the ability to induce the nucleation and crystallization of hydroxyapatite during de/remineralization processes. Finally, the MMSi hydrosol was mixed with commercialized toothpaste to explore its efficacy in dentin tubule occlusion via cycling de/remineralization processes. As a result, compared to the MM hydrosol, the toothpaste containing the MMSi hydrosol presented excellent acid-resistant ability and dentin tubule occlusion outcomes, which indicated that the MMSi hydrosol could be a potential promise in the long-term treatment of DH.

Potassium oxalate-based mouth rinse for rapid relief in dentinal hypersensitivity

Abstract Dentinal hypersensitivity (DHS) affects about 1.3%–92.1% of the population globally and has a significant impact on the quality of life of the affected individuals. Desensitizing agents that directly block the dentinal tubules or cause chemical blocking of the pulpal nerve endings are commonly recommended for the management of DHS. Potassium oxalate (KO) has been used as a desensitizing agent in the management of DHS. This narrative review aimed to assess the literature related to the efficacy of KO as a desensitizing agent, with a focus on mouth rinses containing 1.4% KO. A comprehensive search of the literature was carried out using PubMed and Google Scholar with relevant keywords. The results from the retrieved articles were assessed, and the findings regarding the efficacy of KO in managing DHS were analyzed. Studies suggest that the usage of 1.4% KO mouth rinses results in the occlusion of dentinal tubules by the formation of acid-resistant calcium oxalate crystals within dentinal tubules and on the dentine surface. These calcium oxalate crystals tend to form a strong bond with the inner surface of the dentinal tubules and lower the hydraulic conductivity of the dentine. These actions of KO can ensure both rapid and long-term relief from DHS.

Novel biomimetic peptide-loaded chitosan nanoparticles improve dentin bonding via promoting dentin remineralization and inhibiting endogenous matrix metalloproteinases

ObjectiveThis study aims to synthesize novel chitosan nanoparticles loaded with an amelogenin-derived peptide QP5 (TMC-QP5/NPs), investigate their remineralization capability and inhibitory effects on endogenous matrix metalloproteinases (MMPs), and evaluate the dentin bonding properties of remineralized dentin regulated by TMC-QP5/NPs. MethodsTMC-QP5/NPs were prepared by ionic crosslinking method and characterized by dynamic light scattering method, scanning electron microscopy, transmission electron microscope, atomic force microscope, Fourier transform infrared spectroscopy, and differential scanning calorimetry. The encapsulation and loading efficiency of TMC-QP5/NPs and the release of QP5 were examined. To evaluate the remineralization capability of TMC-QP5/NPs, the mechanical properties, and the changes in structure and composition of differently conditioned dentin were characterized. The MMPs inhibitory effects of TMC-QP5/NPs were explored by MMP Activity Assay and in-situ zymography. The dentin bonding performance was detected by interfacial microleakage and microshear bond strength (μSBS). ResultsTMC-QP5/NPs were successfully synthesized, with uniform size, good stability and biosafety. The encapsulation and loading efficiency of TMC-QP5/NPs was respectively 69.63 ± 2.22% and 13.21 ± 0.73%, with a sustained release of QP5. TMC-QP5/NPs could induce mineral deposits on demineralized collagen fibers and partial occlusion of dentin tubules, and recover the surface microhardness of dentin, showing better remineralization effects than QP5. Besides, TMC-QP5/NPs significantly inhibited the endogenous MMPs activity. The remineralized dentin induced by TMC-QP5/NPs exhibited less interfacial microleakage and higher μSBS, greatly improved dentin bonding. SignificanceThis novel peptide-loaded chitosan nanoparticles improved resin-dentin bonding by promoting dentin remineralization and inactivating MMPs, suggesting a promising strategy for optimizing dentin adhesive restorations.

In-depth occlusion of dentine tubules via the application of (poly-L-aspartic acid)‑strontium and phosphate/fluoride to treat dentine hypersensitivity

Dentine hypersensitivity (DH) is a common oral health issue and occlusion of the exposed dentinal tubules (DTs) is regarded as the most effective therapeutic treatment nowadays. However, it is still difficult to develop easy and effective strategies for deep occlusion of DTs. In this study, we develop a strategy for occluding DTs deeply and compactly via simple application of occlusion media including (poly-L-aspartic acid)‑strontium (PAsp‑strontium) and phosphate/fluoride. The bonding of strontium ions to poly-L-aspartic acid formed a positively charged PAsp‑strontium complexes. After application of 15 min each, the PAsp‑strontium and phosphate/fluoride rapidly penetrated into the DTs in turn via the electrostatic interaction, then occluded the DTs with crystals up to a depth of 150 μm. The occlusion within DTs was resistant to abrasive and acidic challenges. The occlusion media performed better than commercial desensitizers Duraphat and Gluma. Moreover, this strategy possessed sufficient biocompatible and excellent performance in vivo. The application of occlusion media would shed light on in the management of DH.

Evaluation of Dentin Tubule Occlusion Using Pre-Treatment with No-Ozone Cold Plasma: An In Vitro Study

Dentin hypersensitivity is a common disease of the oral cavity, which renders the tooth extremely sensitive to stimuli. These symptoms usually result from the exposure of the dentinal tubules to the external environment. There is a need for a treatment for dentinal hypersensitivity that can overcome the shortcomings of the existing agents. This study thus aimed to assess the therapeutic efficacy of no-ozone cold plasma (NCP), which was developed for safe use in the oral cavity, in conjunction with 1.23% acidulated phosphate fluoride (APF) and hydroxyapatite (HA), which are widely used conventional treatments of hypersensitivity. The fluoride content was evaluated using electron probe micro-analyzer (EPMA) analysis. Moreover, we confirmed the effect of NCP pre-treatment on the dentinal tubule occlusion by APF and HA as follows: scanning electron microscopy and energy dispersive X-ray spectrometry were employed to analyze the exposed dentinal tubules, and the calcium and phosphorus content were measured. Furthermore, an additional experiment was conducted using a metal mesh to analyze the working elements of NCP. All experimental results were analyzed by one-way analysis of variance and then by using the Turkey test as a post hoc test. EPMA analysis confirmed that the fluoride content of the APF and NCP group was significantly higher than that of the APF group (p < 0.001). The fluoride content of the group treated with APF and NCP equipped with a metal mesh was significantly lower than that in the group treated with APF and NCP and the group treated with APF and NCP equipped with a cotton mesh (p < 0.01). Moreover, the group treated with NCP pre-treated with HA and APF exhibited significantly greater dentinal tubule occlusion than the other groups (p < 0.05). The same result was confirmed by calculating the calcium/phosphorus ratio (p < 0.05). Pre-treatment of the enamel and dentin surfaces with plasma improved hypersensitivity by enhancing fluoride deposition with APF and dentinal tubule occlusion with HA.

Dentine tubule occlusion effect of hydrolyzed casein in a bioactive glass-based dental desensitizing gel

ObjectivesThe effectiveness of three different groups of polyethylene glycol (PEG)-based gels containing powders on dentin hypersensitivity (DH) treatment were assessed and compared with Actimins® as commercial reference group. MethodsHydroxyapatite nanorods (nHA) and sol-gel-derived 45S5 bioglass (SGD 45S5) powders were synthesized through hydrothermal and sol-gel methods, respectively. First, 25 demineralized dentin disks were divided into five groups. Then, the prepared gels based on 45S5 bioglass with and without hydrolyzed casein (HC) as experimental, nHA gel and Actimins® as positive and commercial reference groups were applied twice a day on disks by a micro applicator. To mimic the oral environment, treated disks were immersed in artificial saliva in a water bath at 37 °C for 7 days. However, in the negative control group, no agent was applied on the samples. FE-SEM, EDS, AFM, and XRD were performed to assess tubule occlusion. One-way ANOVA test was used for statistical analysis and p*<0.05 was set as the significance level. ResultsThe nHA with an average aspect ratio of 2.77 and the SGD 45S5 powders with a polygonal morphology and the average size of 48.64±11.38 µm were synthesized. After treatment, tubule occlusion in HC-SGD 45S5 and nHA gels were shown to be higher than other groups. The root mean square roughness (Rrms) of the above-mentioned gels showed to be 121.54±9.25 nm, and 312.6 ± 9 nm, respectively. ConclusionThe nHA containing group exhibited the highest tubule occlusion efficiency (i.e., tubule diameter of 0.92±0.32 µm) with a superior mineral precipitation. HC as a novel material demonstrates to be potentially beneficial in DH treatment. Clinical significanceDH as a common issue may be reduced or eliminated by occlusion of patent dentinal tubules. There are various types of desensitizing agents capable of controlling the DH by the occlusion of patent dentinal tubules. The desensitizing gels developed in this study showed to be promising for clinical and home-use applications.

Composite materials of amorphous calcium phosphate and bioactive glass nanoparticles for preventive dentistry

Amorphous calcium phosphates and bioactive glasses are two of the most used materials in dentistry thanks to their ability to release remineralizing ions and reduce dentinal hypersensitivity by occluding exposed dentinal tubules. Here, we have synthesized composites of fluoride-doped amorphous calcium phosphate (FACP) and mesoporous bioactive glass nanoparticles (MBGNs) to obtain functional materials that possess both the capability to release dental remineralizing ions of FACP and both the excellent desensitizing activity of MBGNs. The procedure described in this work allows us to obtain FACP/MBGN composites with different compositions (i.e., FACP:MBGN weight ratio) in which the components have formed a deeply intertwined nanostructure. Composites’ ion release (i.e. Ca, P, F, and Si) in acidic artificial saliva is different from that of the single components or their physical mixture, corroborating the formation of composite materials. Moreover, thanks to the presence of FACP, the composites have superior bioactivity than the MBGNs alone. Dental enamel remineralization and efficacy of dentinal tubules occlusion by the investigated composites were preliminarily tested in vitro on human dental hard tissues using scanning electron microscopy. Data revealed that the composites induced a satisfactory remineralization of enamel and dentin thanks to the FACP component, and a positive tubule occlusion thanks to the MBGNs component. Finally, our results demonstrate that FACP/MBGN composites are highly promising materials for preventive dentistry.

Nano-CT characterization of dentinal tubule occlusion in SDF-treated dentin

Dentin hypersensitivity is an oral health concern affecting a large percentage of the world's adult population. Occlusion of the exposed dentinal tubules is among the treatment options available, and silver diammine fluoride (SDF) is an occluding agent used for interrupting or dampening the stimulus of the dental pulp nerves that produce pain. In addition to dentin permeability testing, the evaluation of desensitizing agents occluding dentinal tubules strongly relies on microscopic techniques, such as scanning electron microscopy (SEM). Limitations of SEM are that it provides only surface images that lack detailed information on the depth of penetration and amount of material present within the treated specimen, and it is prone to sample preparation artifacts. Here, we present high-resolution X-ray computed tomography (nano-CT) as a potential method for investigating dentin specimens with occluded tubules. We studied human dentin treated with SDF as an exemplary dentinal occlusion treatment option. We evaluated the silver deposits formed on the dentin surface region near the dentinal tubules and in the tubular regions using cross-section SEM, Energy Dispersive X-ray (EDX) analysis, and nano-CT. The resulting images obtained by SEM and nano-CT had comparable resolutions, and both techniques produced images of the tubules' occlusion. Nano-CT provided three-dimensional images adequate to quantitate tubule size and orientation in space. Moreover, it enabled clear visualization of dentinal tubules in any virtual plane and estimation of the amount and depth of occluding material. Thus, nano-CT has the potential to be a valuable technique for evaluating the occluding effects of virtually any material applied to dentinal tubules, supporting deciding between the best occluding treatment options.

The Effect of Three Desensitizing Toothpastes on Dentinal Tubules Occlusion and on Dentin Hardness.

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

Efficiency of Various Tubular Occlusion Agents in Human Dentin after In-Office Tooth Bleaching.

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

In‐Depth Occlusion of Dentinal Tubules and Rapid Remineralization of Demineralized Dentin Induced by Polyelectrolyte‐Calcium Complexes (Adv. Healthcare Mater. 19/2023)

In‐Depth Occlusion of Dentinal Tubules and Rapid Remineralization of Demineralized Dentin Induced by Polyelectrolyte‐Calcium Complexes (Adv. Healthcare Mater. 19/2023)

Effect of Commercially Available Nano-Hydroxyapatite Containing Desensitizing Toothpaste and Mouthwash on Dentinal Tubular Occlusion: A SEM Analysis.

The aim of this in vitro study was to evaluate and compare the dentinal tubule occlusion using nano-hydroxyapatite (n-HAP) containing toothpaste and mouthwash under a scanning electron microscope. The specimens were randomly divided into two groups with five specimens each: group 1-toothpaste group and group 2-mouthwash group. The percentage of the occluded dentinal tubules was assessed at the baseline, 7th, 14th, 21st, and 28th days under a scanning electron microscope. The toothpaste group showed a higher percentage of occluded dentinal tubules as compared to the mouthwash group at the 7th, 14th, 21st, and 28th days, respectively. It can be concluded that brushing twice daily with n-HAP containing toothpaste for duration of 28 days produced good dentinal tubule occlusion.

Evaluation of dentinal tubule occlusion and pulp tissue response after using 980-nm diode laser for dentin hypersensitivity treatment.

To evaluate the effectiveness of the 980-nm diode laser for dentinal tubule occlusion, measure the intrapulpal temperature, and investigate the dental pulp response. The dentinal samples were randomly divided into G1-G7 groups: control; 980-nm laser irradiation (0.5 W, 10s; 0.5 W, 10s × 2; 0.8 W, 10s; 0.8 W, 10s × 2; 1.0 W, 10s; 1.0 W, 10s × 2). The dentin discs were applied for laser irradiation and analyzed by scanning electron microscopy (SEM). The intrapulpal temperature was measured on the 1.0-mm and 2.0-mm thickness samples, and then divided into G2-G7 groups according to laser irradiation. Moreover, forty Sprague Dawley rats were randomly divided into the laser-irradiated group (euthanized at 1, 7, and 14days after irradiation) and the control group (non-irradiated). qRT-PCR, histomorphology, and immunohistochemistry analysis were employed to evaluate the response of dental pulp. SEM indicated the occluding ratio of dentinal tubules in the G5 (0.8 W, 10s × 2) and G7 (1.0 W, 10s × 2) were significantly higher than the other groups (p < 0.05). The maximum intrapulpal temperature rises in the G5 were lower than the standard line (5.5 ℃). qRT-PCR showed that the mRNA expression level of TNF-α and HSP-70 upregulated significantly at 1day (p < 0.05). Histomorphology and immunohistochemistry analysis showed that, compared with the control group, the inflammatory reaction was slightly higher at the 1 and 7days (p < 0.05) and decreased to the normal levels at 14days (p > 0.05). A 980-nm laser at a power of 0.8 W with 10s × 2 defines the best treatment for dentin hypersensitivity in terms of compromise between the efficacy of the treatment and the safety of the pulp. The 980-nm laser is an effective option for treating dentin sensitivity. However, we need to ensure the safety of the pulp during laser irradiation.

Investigation of Dentinal Tubule Occlusion by a Desensitizing Dentifrice: an in-Vitro Sem Analysis

The purpose of this study was to compare patent dentin tubules to in vitro dentin tubules in order to assess the dentin tubule occluding impact of a dentifrice incorporating Pro-Argin Technology (Colgate Sensitive Plus). Methods: The diameter of the dentine tubule was measured using scanning electron microscopy (SEM) on 20 produced dentin discs that were either left untreated or treated with the dentifrice. To evaluate tubule patency, microphotographs were obtained at a 2000x magnification. The dentifrice covered the treated sample, filling the dentinal tubule and decreasing or closing the tubule opening, according to SEM imaging results. Conclusion: According to pertinent statistical analysis, Pro-argin technology efficiently blocked dentinal tubules, making it suitable for use as a dental anti-sensitivity agent.

Evaluation of the effectiveness of different treatment approaches in preventing coronal discoloration caused by regenerative endodontic treatment.

This study aimed to evaluate the effectiveness of Teethmate desensitizer, a dentin bonding agent (DBA), Nd:YAG laser, and Er:YAG laser, which provides dentin tubule occlusion in the pulp chamber with different mechanisms, in preventing tooth discoloration due to regenerative endodontic treatment. One hundred five extracted maxillary human incisors with single roots and single canals were included in the study. The apical third of each tooth was resected below the enamel-cementum junction (CEJ) to obtain a standard root length as 10 ± 1mm. Root canal preparation was performed using the ProTaper Next files up to X5. Root canals were prepared with Gates Glidden (# 2-4) burs to simulate the immature root apex and an apical diameter of 1.1 ± 0.1mm was obtained. The teeth were randomly divided into 7 groups (n = 15): DBA, Teethmate, Nd:YAG, Er:YAG, Biodentine, Blood, and Negative Control. Relevant dentin tubule occlusion methods were applied to DBA, Teethmate, Nd:YAG, and Er:YAG groups. Following dentin tubule occlusion procedures, Biodentine was placed on the blood clot after filling the root canals with blood up to 4mm below the CEJ. No dentin tubule occlusion procedure was applied for Blood and Biodentine groups. Color measurement was performed with the spectrophotometer Vita Easyshade Advance before treatment, immediately after treatment, and at days 7, 30, and 90. Data were converted to L*a*b color values of Commission International de I'Eclairage (CIE L*a*b) and ΔE values were calculated. Two-way ANOVA and post hoc Tukey test (p = 0.05) were performed for statistical analysis. A clinically detectable color change was observed in all groups except for the negative control (ΔE ≥ 3,3). It was observed that Biodentine used alone has a potential for discoloration. It was determined that as the contact time with blood increased, tooth discoloration increased. However, no significant difference was found between dentin tubule occlusion methods in preventing color change (p > 0.05). It was determined that no dentin tubule occlusion method could 100% prevent discoloration caused by RET. DBA and Teethmate, which do not have a significant difference in terms of preventing color change, are considered to be suitable for dentin tubule occlusion due to their ease of application and low cost compared to Nd:YAG laser and Er:YAG laser.

A SEM Evaluation of the Permeability of Different Desensitizing Methods on Occlusion of Dentinal Tubules: An In-vitro Study.

The purpose of the current research was to assess the permeability of three various desensitizing techniques on dentinal tubule occlusion using a scanning electron microscope (SEM). For this research, 100 human sound premolar teeth that were extracted for orthodontic purposes were gathered. With the aid of a water-cooled diamond saw, the teeth were divided in a mesiodistal (vertically) orientation. A sectioned sample (5 mm long by 5 mm wide by 3.5 mm deep), including the cervical region, was taken from each buccal side. To fully open the dentinal tubules, these samples were then kept in 17% ethylenediaminetetraacetic acid (EDTA) for 40 minutes. The samples were divided into four groups (n = 25), each receiving the following dentin surface treatments: Group I: Control, Group II: Samples received NaF 5% varnish treatment, Group III: Samples received diode laser treatment, and Group IV: Samples received CPP-ACP treatment. An SEM was used to inspect each specimen at a magnification of about × 3000 and photomicrographs was assessed. The maximum occlusion of dentinal tubules was found in samples were treated with Diode laser (2.96 ± 0.14) followed by samples treated with NaF 5% varnish (3.38 ± 0.10), samples were treated with CPP-ACP (3.42 ± 0.06) and control group (4.26 ± 0.19). There was a statistically significant difference found between the groups. In conclusion, all three desensitizing methods used in the present study were successful in the occlusion of dentin tubules. But the application of the Diode laser was effective in the reduction of dentin permeability compared to NaF 5% varnish and CPP-ACP. Dentin hypersensitivity (DH) is characterized by a brief period of intense discomfort. One approach to managing DH is to obstruct dentin tubules in order to decrease dentin permeability. There are many substances that can reduce hypersensitivity, but the finest commercially available substance for treating the condition by occluding the tubes should be acknowledged.

Amorphous Calcium Magnesium Fluoride Phosphate—Novel Material for Mineralization in Preventive Dentistry

This paper describes novel and innovative amorphous calcium magnesium fluoride phosphate (ACMFP) core-shell microparticles that may be applied in preventive dentistry for the prevention of caries and the treatment of dentin hypersensitivity. The particles can be synthesized with varied fluoride content, up to approximately 6 wt%, without any observable differences in morphology or crystallinity. Fluoride release from the particles is correlated to the fluoride content, and the particles are readily converted to fluoride-substituted hydroxyapatite or fluorapatite in a simulated saliva solution. The remineralization and dentin tubule occlusion potential of the particles was evaluated in vitro on acid-etched dentin specimens, and treatment with the ACMFP particles resulted in complete tubule occlusion and the formation of a dense mineralization layer. The acid resistance of the mineralization layer was improved compared to treatment with analogous particles without fluoride inclusion. A cross-sectional evaluation of dentin specimens after treatment revealed the formation of high aspect ratio fluorapatite crystals and poorly crystalline hydroxyapatite, respectively. The particles of the current study provide a single source vehicle of readily available calcium, phosphate, and fluoride ions for the potential remineralization of carious lesions as well as exposed dentin tubules for the reduction of hypersensitivity.

Oyster shell-derived nano-hydroxyapatite and proanthocyanidin pretreatment on dentinal tubule occlusion and permeability before and after acid challenge—an in vitro study

This in vitro study evaluated the dentinal tubule occlusion (TO), depth of penetration (DoP), and dentin permeability (DP) of oyster shell-derived nanohydroxyapatite (os-nHAp) with and without 15% proanthocyanidin (PA) pretreatment. os-nHAp was synthesized via the precipitation method and it was characterized. The morphology and particle size of os-nHAp were analyzed using a high-resolution transmission electron microscope (HRTEM). Cytotoxicity of os-nHAp, PA/os-nHAp, and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) was assessed by (3-(4,5-dimethythiazol-2-yl) 2,5-diphenyl tetrazolium bromide (MTT) assay using human osteosarcoma (MG-63) cell line. One hundred and ninety-seven dentin discs of 3 mm thickness were prepared from the crown portion of extracted human teeth. The dentinal surfaces of the discs were etched for 2 min with 6% citric acid to simulate dentin hypersensitivity. Five discs were randomly selected and the patency of dentinal tubules was confirmed using a scanning electron microscope (SEM). The remaining 192 discs were divided into four groups (n = 48) depending on the type of remineralization as follows: group 1: os-nHAp, group 2: PA/os-nHAp, group 3: CPP-ACP, and group 4: no treatment. The remineralization protocol was followed for 21 days. Out of the 48 dentin discs in each group, 32 discs were used to evaluate dentinal tubule occlusion (TO) and depth of penetration (DoP) using SEM. The remaining 16 discs were subjected to an assessment of dentin permeability (DP) using a hydraulic conductance model. TO, DoP and DP were evaluated after remineralization and acid challenge. Characterization studies confirmed the presence of pure phase apatite. HRTEM confirmed the nanometric particle size of os-nHAp. MTT assay results showed that all the tested materials exhibited >80% cell viability when tested up to a concentration of 100 µg/mL. The results demonstrated a significantly higher mean percentage of TO, DoP, and lesser mean DP after remineralization in groups 1, 2, and 3 (p < 0.05). After the acid challenge, group 3 showed a significant reduction in TO and DoP, and increased DP (p < 0.05). However, no such changes were observed in groups 1 and 2. Within the limitations of this study, it can be concluded that os-nHAp and PA/os-nHAp could serve as potential and durable therapeutic agents in the treatment of dentin hypersensitivity.Graphical

In-Depth Occlusion of Dentinal Tubules and Rapid Remineralization of Demineralized Dentin Induced by Polyelectrolyte-Calcium Complexes.

Dentin hypersensitivity (DH) is triggered by external stimuli irking fluid flow through exposed dentinal tubules (DTs). Three commercially available desensitizing agents as control in this study only achieve limited occlusion depths of ≈10µm in the DTs as well as scarce remineralization of demineralized dentin matrix. Herein, polyelectrolyte-calcium complexes pre-precursor (PCCP) process is proposed for managing DH that demineralized dentin with exposed DTs is rubbed with ultrahighly concentrated polyelectrolyte-calcium suspension (4g L-1 -5.44m) followed by phosphate solution (3.25m), each 10min, leading to heavy remineralization of demineralized dentin and compact occlusion of the DTs over 200µm after 1 day of in vitro and in vivo incubation. For the first time, it is demonstrated that the PCCP process relies on the pH-dependent electrostatic attraction between electropositive polyelectrolyte-calcium complexes and electronegative inwalls of DTs comprised of collagen fibrils and hydroxyapatite crystals under alkaline condition. The PCCP process might shed light on a promising dentin desensitizing strategy for DH management via rapid in-depth DT occlusion and remineralization of demineralized dentin.

Evaluation of the effectiveness of three different desensitizing agents in dentinal tubule occlusion using scanning electron microscope

Evaluation of the effectiveness of three different desensitizing agents in dentinal tubule occlusion using scanning electron microscope