Comparative Evaluation of Er: YAG Laser, Diode Laser, and Novamin Technology for Dentinal Tubule Occlusion: An In-Vitro Scanning Electron Microscope (SEM) and Energy Dispersive X-Ray Analysis (EDX) Study.

BACKGROUND: Dentinal hypersensitivity is a brief and painful oral condition that is characterized by an abrupt shooting sensation. Stimulation occurs when hot, cold, sweet, or sour food comes into contact with exposed dentinal tubules. The present study used a scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDX) to investigate the efficacy of Er: YAG, 810 nm diode LASER, and NovaMin Technology in obstructing dentinal tubules. MATERIAL AND METHODS: We extracted the outer layers of 30 human teeth to expose the tubules and then treated the surfaces with 17% ethylenediaminetetraacetic acid (EDTA) to create an etched effect. Three cohorts were created from the portions. Group A was subjected to the application of Erbium:Yttrium-Aluminum-Garnet (Er: YAG) laser with a power output of 2W in the non-contact mode for 1 minute. Group B was subjected to the application of an 810nm diode laser with a power output of 1W in continuous mode for 30 seconds. Group C was subjected to the application of NovaMin paste, which contains a 927 ppm fluoride content. Following the therapy, occluded dentinal tubules were analyzed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) for both quantitative and qualitative examination. The data analysis was conducted using a one-way analysis of variance (ANOVA) and Tukey's test, with a significance threshold of 0.05. RESULTS: The average percentages of complete blockage of dentinal tubules in Groups A, B, and C were evaluated using the number of entirely unobstructed dentinal tubules at magnifications of 2000X (F = 3.05, p = 0.064), 5000X (F = 5.33, p = 0.011), and 10000X (F = 8.63, p = 0.001). The count of partially open dentinal tubules seen at magnifications of 2000X, 5000X, and 10000X was F = 10.15 (P < 0.001), F = 5.97 (p = 0.007), and F = 2.12 (p = 0.140) accordingly. CONCLUSION: NovaMin technology has demonstrated more effectiveness in blocking dentinal tubules compared to 810nm diodes and Er: YAG lasers.

The Synergistic Effect of Ozonated Oil and Desensitising Toothpaste on Dentinal Tubule Occlusion: An In Vitro Study.

Introduction Dentin hypersensitivity (DH) is the most common problem encountered by clinicians. It can be managed either by blocking neural activities or by occluding tubules. Ozonated oil facilitates the simple passage of desensitizing agents into dentinal tubules. Aim This study aimed to evaluate the effect of ozonated oil on dentinal tubule occlusion before and after the application of desensitizing toothpaste. Materials and methods The study was carried out in Kalinga Institute of Dental Sciences, KIIT (Deemed to be University), Bhubaneswar, India. The sample size of the study was 80. The first group contained specimens for control. The second group comprised specimens treated with ozonated oil. The third group comprised specimens being treated with a desensitizing agent. The fourth group contained specimens treated with both the desensitizing agent and ozonated oil. The specimens then received an acid challenge. The specimens were observed under a scanning electron microscope (SEM) before any therapy, after the application of the therapeutic agents and after the 37.5% ortho-phosphoric acid challenge. Results Inferential statistics to compare between the groups was calculated using one-way analysis of variance (ANOVA) statistics. Post-hoc Tukey's honestly significant difference (HSD) was performed to compare the groups. The mean scores of the partial tubular occlusion of Group 1, Group 2, Group 3 and Group 4 before the acid challenge were 0.035, 0.691, 0.564 and 0.368, respectively. The maximum score was obtained in the case of Group 2, which was statistically significant. The mean scores for partial tubule occlusion after the acid challenge for Group 1, Group 2, Group 3 and Group 4 were 0.055, 0.531, 0.733 and 0.142, respectively. There was evidence of maximum partial tubule occlusion after the acid treatment in the case of Group 3. The mean scores of Group 1, Group 2, Group 3 and Group 4 before the acid challenge were 0.019, 0.309, 0.442 and 0.609, respectively. The maximum score was obtained in the case of Group 4, implying a greater number of total tubular occlusions before the acid challenge. The mean scores of the total tubular occlusions after the acid challenge for Group 1, Group 2, Group 3 and Group 4 were 0.047, 0.465, 0.272 and 0.890, respectively. There was evidence of maximum tubule occlusion in the case of Group 4, which was statistically significant. Conclusion Overall, the application of a desensitizing toothpaste with ozonated oil holds promise as a potentially more effective treatment approach for DH. Further research and clinical studies may be needed to fully validate its efficacy and safety in dental practice.

Biomineralization-Inspired Anti-Caries Strategy Based on Multifunctional Nanogels as Mineral Feedstock Carriers.

Background: Dentin caries remains a significant public concern, with no clinically viable material that effectively combines remineralization and antimicrobial properties. To address this issue, this study focused on the development of a bio-inspired multifunctional nanogel with both antibacterial and biomineralization properties. Methods: First, p(NIPAm-co-DMC) (PNPDC) copolymers were synthesized from N-isopropylacrylamide (NIPAm) and 2-methacryloyloxyethyl-trimethyl ammonium chloride (DMC). Subsequently, PNPDC was combined with γ-polyglutamic acid (γ-PGA) through physical cross-linking to form nanogels. These nanogels served as templates for the mineralization of calcium phosphate (Cap), resulting in Cap-loaded PNPDC/PGA nanogels. The nanogels were characterized using various techniques, including TEM, particle tracking analysis, XRD, and FTIR. The release properties of ions were also assessed. In addition, the antibacterial properties of the Cap-loaded PNPDC/PGA nanogels were evaluated using the broth microdilution method and a biofilm formation assay. The remineralization effects were examined on both demineralized dentin and type I collagen in vitro. Results: PNPDC/PGA nanogels were successfully synthesized and loaded with Cap. The diameter of the Cap-loaded PNPDC/PGA nanogels was measured as 196.5 nm at 25°C and 162.3 nm at 37°C. These Cap-loaded nanogels released Ca2+ and PO43- ions quickly, effectively blocking dental tubules with a depth of 10 µm and promoting the remineralization of demineralized dentin within 7 days. Additionally, they facilitated the heavy intrafibrillar mineralization of type I collagen within 3 days. Moreover, the Cap-loaded nanogels exhibited MIC50 and MIC90 values of 12.5 and 50 mg/mL against Streptococcus mutans, respectively, with an MBC value of 100 mg/mL. At a concentration of 50 mg/mL, the Cap-loaded nanogels also demonstrated potent inhibitory effects on biofilm formation by Streptococcus mutans while maintaining good biocompatibility. Conclusion: Cap-loaded PNPDC/PGA nanogels are a multifunctional biomimetic system with antibacterial and dentin remineralization effects. This strategy of using antibacterial nanogels as mineral feedstock carriers offered fresh insight into the clinical management of caries.

A Comparative Analysis of the Occluding Effects on Dentinal Tubules With the Use of Er:YAG Laser and a Commercially Available Desensitizing Agent: An In Vitro Scanning Electron Microscopic Study.

Objective This in vitro scanning electron microscopic (SEM) study aimed to compare the effect of Er:YAG laser and a commercially launched dental product namely 8% arginine-calcium carbonate on exposed dentinal tubules. Materials and methods A total of 120 tooth samples prepared from healthy maxillary first premolars extracted due to orthodontic reasons were grouped randomly into four groups of 30 samples each - Group I: control group (C); Group II: laser group (LG); Group III: toothpaste group (TP) and Group IV: laser + toothpaste group (LT). The samples in Group II-IV were treated with the respective test agents and were placed under SEM to study the changes in the dentinal tubule number and diameter. The data obtained from SEM were then subjected to statistical analysis using an unpaired t-test. Results The unpaired t-test revealed extreme statistical differences in means between the test and the control groups and among the test groups (p<0.0001). The results we obtained within the scope of this study showed that both the Er:YAG laser (1.3 W, 100 mJ, 3 Hz, 60 s twice) and dentifrice containing 8% arginine-calcium carbonate as the main ingredient can significantly reduce the number and diameter of the open dentinal tubules. Conclusion Our findings have demonstrated that both the 8% arginine-calcium carbonate technology and Er:YAG laser successfully reduced the number and diameter of the open dentinal tubules and hence can be promising agents to deal with dentinal hypersensitivity in future clinical studies.

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

OBJECTIVES: To evaluate the effectiveness of the 980-nm diode laser for dentinal tubule occlusion, measure the intrapulpal temperature, and investigate the dental pulp response. MATERIALS AND METHODS: The dentinal samples were randomly divided into G1-G7 groups: control; 980-nm laser irradiation (0.5 W, 10 s; 0.5 W, 10 s × 2; 0.8 W, 10 s; 0.8 W, 10 s × 2; 1.0 W, 10 s; 1.0 W, 10 s × 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 14 days after irradiation) and the control group (non-irradiated). qRT-PCR, histomorphology, and immunohistochemistry analysis were employed to evaluate the response of dental pulp. RESULTS: SEM indicated the occluding ratio of dentinal tubules in the G5 (0.8 W, 10 s × 2) and G7 (1.0 W, 10 s × 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 1 day (p < 0.05). Histomorphology and immunohistochemistry analysis showed that, compared with the control group, the inflammatory reaction was slightly higher at the 1 and 7 days (p < 0.05) and decreased to the normal levels at 14 days (p > 0.05). CONCLUSIONS: A 980-nm laser at a power of 0.8 W with 10 s × 2 defines the best treatment for dentin hypersensitivity in terms of compromise between the efficacy of the treatment and the safety of the pulp. CLINICAL RELEVANCE: 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.

A Comparative Evaluation of Efficacy of BioMin F and Propolis Containing Toothpastes on Dentinal Tubule Occlusion with and Without Use of an Adjunct 810 nm Diode Laser: An In vitro Scanning Electron Microscope Study.

Introduction: Dentinal hypersensitivity (DH) is a common chronic condition that affects a high proportion of the adult population and is one of the main reasons why patients seek dental opinion and treatment. Despite considerable success in reducing DH, unfortunately, most of the present methods can provide only temporary and unpredictable desensitization. Therefore, new treatment methods that are effective for long periods and at the same time do not have the complications are needed. Recently, two new desensitizing agents BioMin F and Propolis have been introduced for the treatment of DH. Aim: The aim of the study was to compare and evaluate the efficacy of BioMin F and Propolis containing toothpastes on dentinal tubule occlusion with and without the use of an adjunct 810 nm Diode Laser. Materials and Methods: Forty-five freshly extracted teeth were taken out of which thirty were sectioned into halves and divided into four test groups BioMin F, Propolis, BioMin F + Laser, and Propolis + Laser and control group. All the specimens were treated twice a day for 7 days and then evaluated under scanning electron microscope for partial and complete dentinal tubule occlusion. Results: A significantly higher number of completely occluded tubules were seen in BioMin F + laser group followed by Propolis + laser, Biomin F, and Propolis. Conclusion: Combination approach of desensitizing agent and laser provided a better result than the desensitizing agent alone and when compared individually Biomin F was more effective desensitizer as compared to Propolis.

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 ≈10 µm 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 (4 g L-1 -5.44 m) followed by phosphate solution (3.25 m), each 10 min, leading to heavy remineralization of demineralized dentin and compact occlusion of the DTs over 200 µm 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.

A novel rapidly mineralized biphasic calcium phosphate with high acid-resistance stability for long-term treatment of dentin hypersensitivity.

OBJECTIVES: Treating dental hypersensitivity (DH) rapidly and maintaining long-term effectiveness remains challenging. We aimed to address this problem by fabricating a novel rapidly mineralized biphasic calcium phosphate (RMBCP), which could rapidly elicit mineralization to form hydroxyapatite (HA) and perform excellent acid-resistant stability, thus effectively blocking the exposed dental tubules and protecting them from acid attack. METHODS: RMBCP was firstly synthesized by precisely adjusting the molar ratio of acetic acid and calcium hydroxide and characterized by X-ray diffraction (XRD), X-ray fluorescence microprobe (XRF), Fourier-transform infrared (FTIR) spectrometer, scanning electron microscope (SEM), and transmission electron microscope (TEM). Subsequently, using a commercialized desensitizing agent, 45S5 bioglass (BG), as the control group, the mineralization performance of RMBCP was investigated in simulated body fluid (SBF), Dulbecco's modified eagle medium (DMEM), and even slightly acidic artificial saliva (pH=6.6). Moreover, the biocompatibility of RMBCP was studied. Finally, the tubule occlusion effect and acid-resistant stability of RMBCP were evaluated in vitro and in vivo. RESULTS: The rapid mineralization behavior of RMBCP could easily adhere to the dentin surface and block the dentinal tubules completely in vitro and in vivo within 7days. RMBCP performed high acid-resistant stability to maintain the long-term therapeutic effect of DH treatment. SIGNIFICANCE: Developing novel bioactive calcium phosphate materials with the ability to trigger mineralization for HA formation rapidly will be an effective strategy for the long-term treatment of dentin hypersensitivity.

Influence of calcium-based desensitizing toothpastes on the bonding performance of universal adhesive.

The study evaluated the effect of calcium-based desensitizing toothpastes on the dentinal tubule occlusion and its influence on the dentin bond strength of universal adhesive. Mid-coronal dentin samples were prepared for hypersensitivity model and treated by the following calcium-based desensitizing toothpastes: no treatment (Control), Clinpro (fTCP), Pro-Relief (Pro-Argin), and Repair & Protect (Novamin). Single Bond Universal adhesive was applied in self-etch or etch-and-rinse mode. The dentinal tubule occlusion and adhesion interface were evaluated under scanning electron microscope (SEM). A double-fluorescence technique was used to examine interfacial permeability under confocal laser scanning microscopy (CLSM). The micro-tensile bond strength (µTBS) was employed, followed by the fracture interface observation. SEM showed the toothpastes occluded dentinal tubules, and the occlusion exhibited stability against acid and abrasion. Hindered resin infiltration was observed in the adhesion interface after desensitization. CLSM showed more water permeation within or under the adhesion interface in etch-and-rinse mode than self-etch mode. Desensitization decreased the µTBS in self-etch mode. When using etch-and-rinse mode, the desensitized samples presented similar µTBS to the control group. No difference in µTBS was found between the two bonding modes, except for the control group. Calcium-based desensitizing toothpastes can effectively occlude the exposed dentinal tubules with acid-resistant and abrasion-resistant stability. The desensitization reduced the dentin bond strength of the universal adhesive system in self-etch mode but did not affect the bond strength of etch-and-rinse mode.

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.

Polyzwitterion Manipulates Remineralization and Antibiofilm Functions against Dental Demineralization.

Biomineralization technology has become a trend for the arrest and prevention of dental caries. In particular, the bioactivity and ability to release large amounts of Ca2+ and PO43- ions make amorphous calcium phosphate (ACP) for hard tissue remineralization are highly desired. However, the instability of ACP limits its clinical application. Under continuous bacterial challenge in the oral cavity, the currently developed ACP-based remineralization system lacks the ability to inhibit bacterial adhesion and biofilm formation. Here, a dual-functional nanocomposite with antibiofilm and remineralization properties was designed by combining zwitterionic poly(carboxybetaine acrylamide) (PCBAA) and ACP. The resulting nanocomposite was stable in solution for at least 3 days without any aggregation. The PCBAA/ACP nanocomposite exerted a significant inhibitory effect on the adhesion and biofilm formation of Streptococcus mutans and exhibited bactericidal activities under acidic conditions resulting from bacteria. Moreover, compared with fluoride, this nanocomposite demonstrated superior effects in promoting the remineralization of demineralized enamel and the occlusion of exposed dentinal tubules in vivo and in vitro. The present work provides a theoretical and experimental basis for the use of the PCBAA/ACP nanocomposite as a potential dual-functional agent for arresting and preventing caries.

Hydroxyapatite, a potent agent to reduce dentin hypersensitivity.

OBJECTIVE: To review different modes of application of hydroxyapatite for treatment of dentin hypersensitivity via dentinal tubule occlusion. METHODS: Literature search for the systematic review was done using key words 'hydroxyapatite and dentin hypersensitivity', 'hydroxyapatite and dentinal tubule occlusion', 'hydroxyapatite and dentin permeability', and 'dentinal tubule occlusion' on Pubmed, Science Direct and Web of Science databases for articles published over 10 years, from 2009 to 2018. RESULTS: Of the 132 research articles initially identified, 97(73.5%) related to the 10-year study period. After detailed screening, 16(16.5%) studies were included. The results of in vitro studies showed that application of hydroxyapatite caused dentinal tubule occlusion leading to reduction in dentin permeability and reduction in dentin hypersensitivity. CONCLUSIONS: Hydroxyapatite has the potential to reduce dentin hypersensitivity via dentinal tubule occlusion within 2-8 weeks.

The Amelogenin-Derived Peptide TVH-19 Promotes Dentinal Tubule Occlusion and Mineralization.

In this study, the amelogenin-derived peptide, TVH-19, which has been confirmed to promote mineralization, was evaluated to derive its potential to induce dentinal tubule occlusion. The binding capability of fluorescein isothiocyanate (FITC)-labeled TVH-19 to the demineralized dentin surface was analyzed by confocal laser scanning microscopy (CLSM). Additionally, the sealing function of the peptide was studied through the remineralization of demineralized dentin in vitro. The adsorption results showed that TVH-19 could bind to the hydroxyapatite and demineralized dentin surfaces, especially to periodontal dentin. Scanning electron microscopy analysis further revealed that TVH-19 created mineral precipitates. The plugging rate in the TVH-19 group was higher than that in the PBS group. Moreover, energy-dispersive X-ray spectroscopy (EDX) results indicated that the calcium/phosphorus (Ca/P) ratio of the new minerals induced by TVH-19 was close to that of the hydroxyapatite. Attenuated total internal reflection-Fourier transform infrared (ATR-FTIR) spectrometry and X-ray diffraction (XRD) results indicated that the hydroxyapatite crystals formed via remineralization elongated the axial growth and closely resembled the natural dentin components. These findings indicate that TVH-19 can effectively promote dentin sealing by binding to the periodontal dentin, promoting mineral deposition, and reducing the space between the dentin tubules.

Laboratory evaluation of dentin tubule occlusion after use of dentifrices containing stannous fluoride.

The purpose of this study was to examine the effect of desensitizing dentifrices containing stannous fluoride (SnF2) on dentinal tubule occlusion. Two experimental dentifrices with the same ingredients but different SnF2 concentrations (Group II, 0.4% w/w; Group III, 0.454% w/w) were used; distilled water was used in the control group (Group I). Third molars were collected from Japanese and American dental patients. The crowns were removed and sectioned to obtain dentin discs, which were further cut into quarters. Thirty-six specimens each from Japanese and American patients were divided into three sets (n = 12 each) and assigned to each of the three treatment groups. The specimens were brushed for 10 s twice per day for 4 days. After treatment, the discs were observed by scanning electron microscopy, and the extent of dentinal tubule occlusion in the images was expressed on a five-point categorical scale. Group II and III specimens from Japanese and American patients showed greater dentinal tube occlusion than those from Group I, but the differences were not statistically significant. The present results suggest that both SnF2 concentrations mitigate dentin hypersensitivity, regardless of patient ethnicity.

Effects of Poly(Amidoamine) Dendrimer-Coated Mesoporous Bioactive Glass Nanoparticles on Dentin Remineralization.

Dentin hypersensitivity (DH) is one of the most common clinical conditions usually associated with exposed dentinal surfaces. In this study, we identified the effectiveness of poly(amidoamine) (PAMAM) dendrimer-coated mesoporous bioactive glass nanoparticles (MBN) (PAMAM@MBN) on DH treatment, examining the ion-releasing effect, dentin remineralization, and the occluding effect of dentinal tubules. We synthesized MBN and PAMAM@MBN. After soaking each sample in simulated body fluid (SBF), we observed ion-releasing effects and dentin remineralization effects for 30 days. Also, we prepared 30 premolars to find the ratio of occluded dentinal tubules after applying MBN and PAMAM@MBN, respectively. The results showed that PAMAM did not disrupt the calcium ion-releasing ability or the dentin remineralization of MBN. The PAMAM@MBN showed a better occluding effect for dentinal tubules than that of MBN (p < 0.05). In terms of dentinal tubule occlusion, the gap between MBN was well occluded due to PAMAM. This implies that PAMAM@MBN could be effectively used in dentinal tubule sealing and remineralization.

Assessment of tubule occlusion properties of an experimental stannous fluoride toothpaste: A randomised clinical in situ study.

OBJECTIVES: To evaluate the ability of a modified in situ model to differentiate dentinal tubule occlusion properties of toothpaste formulations over 10 days of treatment. METHODS: This was a single-centre, three-treatment period, crossover, randomised, single-blind study with healthy participants wearing two lower oral appliances, each retaining four dentine samples, for 10 treatment days during each period of the study. Samples were power-brushed ex vivo twice on each treatment day with a Test toothpaste containing 0.454% stannous fluoride, a Control fluoride toothpaste containing 0.76% sodium monofluorophosphate, or mineral water. Dentine samples were subjected to in situ acid challenge (orange juice) on Days 9 and 10. Scanning electron microscopy images obtained at baseline and after 1, 4, 8 and 10 days of treatment were graded for degree of surface coverage by four calibrated examiners; the primary study endpoint was Day 8. RESULTS: After 4, but not 8, days' treatment, the degree of tubule occlusion increased in the dentine samples treated with the Test or Control toothpastes compared with the water-treated samples (p < 0.01 and p < 0.05, respectively). Following the acid challenge (Day 10), there was a statistically significantly greater degree of occlusion in the Test toothpaste-treated dentine samples compared with those treated with water (p < 0.01). No other comparisons were statistically significant. All study treatments were generally well-tolerated. CONCLUSIONS: This modified in situ model was unable to demonstrate statistically significant between-treatment differences in dentinal tubule occlusion after 8 days. Conversely, there are recognised developments that could be made to better identify product differences. Clinicaltrials.gov: NCT02768194. CLINICAL SIGNIFICANCE: Dentine hypersensitivity can be managed through brushing with stannous fluoride toothpastes, which occlude patent dentine tubules. Clinical studies measure pain but in situ models are needed to demonstrate occlusion intra-orally. However, this study did not demonstrate superior occlusion with stannous toothpaste; further methodological development is required to investigate its mode of action.

8DSS peptide induced effective dentinal tubule occlusion in vitro.

OBJECTIVE: Eight repetitive nucleotide sequences of aspartate-serine-serine (8DSS) derived from dentin phosphoprotein (DPP) has been proved to be a good remineralization agency. In this study, 8DSS peptide was employed to induce dentinal tubule occlusion. METHODS: Dentin samples were acid-etched, and then the samples were coated with 8DSS solution. The binding capacity of 8DSS to acid-etched dentin was tested by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Subsequently, the 8DSS-treated dentin samples were immersed in artificial saliva for 1, 2 and 4 weeks. After 4 weeks, the remineralized dentin was treated with 6wt% citric acid (pH 1.5) solution for 1min. Dentin permeability measurement and scanning electron microscopy (SEM) were carried out after different periods. Energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) were used to identify the mineral phase of the regenerated minerals. RESULTS: The results showed that 8DSS had a good binding capacity to the acid-etched dentin, and significantly reduced the dentin permeability by inducing minerals deposited within the dentinal tubules. After 4 weeks, all the dentinal tubules were occluded by large bulk of regenerated minerals, which largely decreased the diameters of the tubules. The regenerated minerals deposited with a deep depth within the dentinal tubules, ensuring an effective occlusion even after an acid challenge. The results of XRD and EDS confirmed that the regenerated minerals were mainly hydroxyapatite (HA). SIGNIFICANCE: 8DSS peptide induced strong dentinal tubule occlusion. 8DSS have a great potential to be used in the treatment of dentin hypersensitivity in the future.

Effect and Stability of Poly(Amido Amine)-Induced Biomineralization on Dentinal Tubule Occlusion.

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.

Comparison of in vitro dentinal tubule occluding efficacy of two different methods using a nano-scaled bioactive glass-containing desensitising agent.

OBJECTIVE: This study aimed to compare the in vitro dentinal tubule occluding efficacy of two different methods using a nano-scaled bioactive glass (BG)-containing desensitising agent. METHODS: Citric acid treated dentine discs were randomly divided into 7 groups (n=8). Group A1, A2 and A3: dentine discs coated with BG desensitising paste; Group B1, B2 and B3: dentine discs coated with BG desensitising paste and covered with matched transparent trays; and control group (GroupC): dentine discs treated with deionised water. Field Emission Scanning Electron Microscopy (FE-SEM) was used to capture topographical images of each dentine discs after they were immersed in artificial saliva for corresponding treatment time and dentinal tubules exposure rates were thus measured. Elemental compositions of dentine discs were identified using Energy-Dispersive X-ray Spectroscopy (EDX). RESULTS: FE-SEM revealed better tubule occluding effects in Group B. Dentinal tubules in Group B3 were totally occluded with continuous homogeneous minerals to a depth of 20.6-24.7µm. Dentinal tubule exposure rates in Group B1, Group B2 and Group B3 were lower than that in Group A1, Group A2 and Group A3. EDX indicated that occluding deposits observed in each group were calcium-deficient hydroxyapatite. CONCLUSIONS: The application of transparent trays in combination with nano-scaled BG-containing desensitising paste could increase the dentinal tubule occluding effectiveness of the latter one and shorten the treatment time. CLINICAL RELEVANCE: Transparent trays could be used in combination with BGs-containing desensitising paste as the containers of the latter one in order to increase the dentinal tubule occluding effectiveness. This could lead to the development of a new therapeutic technique for treating dentine hypersensitivity.

Effect of Water-Cooled Nd:YAG Laser on Dentinal Tubule Occlusion In Vitro.

OBJECTIVE: The objective of this study was to investigate the effect of a new water-cooled Nd:YAG laser on dentinal tubule occlusion. BACKGROUND DATA: The effect of water-cooled Nd:YAG laser on dentinal tubule occlusion has not been reported. METHODS: Acid-etched dentin samples were randomly divided into three groups: (1) dentin control, (2) dentin treated by Nd:YAG laser, (3) dentin treated by water-cooled Nd:YAG laser. After laser irradiation, half of the samples were immersed in a 6 wt% citric acid (pH 1.5) solution for 1 min to evaluate the acid resistance. The morphologies of dentin surfaces were characterized by scanning electron microscopy. The number and diameters of the open dentinal tubules were analyzed by one-way and two-way analyses of variance. RESULTS: Both the Nd:YAG laser and water-cooled Nd:YAG laser melted the superficial layer of dentin, which caused dentinal tubule occlusion in most areas and diameter reduction of the rest open tubules. Microcracks on the dentin surface were only observed in the Nd:YAG laser group. The tubule occlusion induced by the two lasers showed a good acid resistance. CONCLUSIONS: The effect of water-cooled Nd:YAG laser on dentinal tubule occlusion is similar to that of the Nd:YAG laser. The dentinal tubule occlusion induced by the two lasers could resist acid challenge to some extent.