Dentinal Tubule Occlusion Research Articles

Interaction of storage medium and silver diamine fluoride on demineralized dentin.

ObjectiveThe effects of saliva on demineralized dentin and silver diamine fluoride (SDF) were investigated in vitro.MethodsDentin samples stored in deionized water (DIW), buffer solution (BS), basal medium mucin (BMM), and unstimulated whole saliva (UWS) were demineralized for 3 days and immersed in the same storage media. SDF as a 38 mass% solution was applied to the dentin samples for 3 minutes after they had been replaced in their respective medium. Surfaces were analyzed by scanning electron microscopy, energy-dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD).ResultsScanning electron microscopy showed various surface deposits and coatings, including occlusion of dentinal tubules. DIW resulted in the thinnest coating, whereas BMM resulted in the thickest. EDX and XPS showed the formation of metallic silver and silver compounds in all four media, with the greatest formation in BS. XRD indicated that the main product was silver chloride except in DIW. Sulphur was found in BMM and UWS. EDX and XPS detected fluoride and XRD detected calcium fluoride and fluorohydroxyapatite in BS, BMM, and UWS.ConclusionThe interaction between SDF and demineralized dentin was dependent upon the storage medium. BMM provided an outcome most similar to human saliva.

Antibacterial silver-containing mesoporous bioglass as a dentin remineralization agent in a microorganism-challenged environment

ObjectivesTo provide a suitable material capable of treating dentin hypersensitivity with simultaneous active antibacterial activity. MethodsWe developed silver-containing mesoporous bioglass (MBG-Ag) using the sol-gel technique, which loaded silver nanoparticles as promising bacteriostatic agents. The MBG-Ag with a powder-to-liquid ratio of 0.5 g: 0.01 mL were uniformly mixed with 20 %, 30 %, and 40 % phosphoric acid for 5, 10 and 20 min, respectively. Furthermore, we evaluated the occlusion efficiency, depth of penetration, and antibacterial activity of dentin specimens by simulating a Streptococcus mutans (S. mutans) infection on dentin. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) were used to characterize the powders and assess tubule occlusion. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the MBG-Ag against S. mutans were determined via time-killing curves and colony formation assays. ResultsThe MIC ranged from 2.5 to 5 mg/mL, and the MBC ranged from 5 to 10 mg/mL. The highest dentinal tubule occlusion efficiency was over 90 %. The colony formation assay confirmed that 5 mg/mL MBG-Ag mixed with phosphoric acid reached the bactericidal concentration. ConclusionThe MBG-Ag 40PA achieved a good occlusion efficiency and deep apatite precipitation in a short time, implying its superiority in clinical applications. Clinical relevanceThe MBG-Ag formed in this study is a promising candidate for the treatment of demineralized dentin and confers antibacterial effects on the remineralized dentin surface against S. mutans.

Novel Management of Hypersensitive Dentin Using Propolis-based Herbal Desensitizing Agents: An In Vitro Scanning Electron Microscopic Study

The objective of this in vitro study was to assess the efficacy of novel propolis-based varnish against the two conventional varnishes on quantitative and qualitative assessments of occlusion of dentin tubules and resistance to erosive and abrasive wears employing scanning electron microscope (SEM). Thirty human premolars free from caries extracted due to orthodontic reasons were included in the study. Experimental group was done based on treatment received and divided into three groups. Group A: ClinProXT Varnish (n = 10), Group B: MI Varnish (n = 10), and Group C: Propolis Varnish (n = 10) were applied. Teeth were cleaned and decoronation of crown was done with dentin disks. Dentin specimens of dimension 4 × 4 × 2 mm were prepared and subjected to finishing and polishing. The sample specimens were submersed in EDTA solution for a period of five minutes to open up the dentinal tubules. This was followed by treatment with varnishes and subjection to acidic-abrasive challenge. The specimens were analyzed with an image analyzer connected to SEM for the verification of the number of opened dentin tubules. The parameter assessed in SEM includes size, topography and surface characteristics of dentinal tubule were assessed. The obliteration potential of dentinal tubules was assessed with SEM images. Additionally, the dentin surface loss and resistance to acidic and abrasive wear were also evaluated with SEM. Data were analyzed with two-way analysis of variance (ANOVA) with post hoc Tukey's test. MI Varnish caused higher obliteration of dentin tubules followed by ClinproXT Varnish. Propolis Varnish showed the least obliteration of dentinal tubules among tested experimental groups. After acidic-abrasive challenge, Propolis Varnish was found to be more efficient with less material loss among the experimental groups tested. There was an insignificant difference among the MI Varnish and ClinProXT Varnish groups. Simulation of hypersensitive lesions mimicking the clinical scenario was a challenging task in this in vitro study. All varnishes tested in the study had good efficacy in the management of dentin hypersensitivity (DH). Propolis-based varnish had good resistance to material loss after subjection to acidic-abrasive challenge among the tested materials. The casein phosphopeptide (CPP)-amorphous calcium phosphate (ACP)-based MI Varnish had good efficacy to obliterate the dentinal tubules among the tested materials. It was prudent to select the varnishes with good long-term efficacy to survive in the clinical scenario which still remains a challenging task for the clinicians. The stability of the varnish plays a vital role in maintenance of its long-term efficacy. The chemical nature along with the ability of the material to interact with the substrate plays a major role in management of DH.

COMPARATIVE EVALUATION OF THE EFFECTIVENESS OF DESENSITIZING DENTIFRICE AND DENTAL LASER ON DENTINAL TUBULE OCCLUSION- AN INVTRO –SEM STUDY

Background: the present study aims to evaluate whether fluoro calcium phospho silicate (Biomin or Elzenes) or in combination with Diode laser has better dentinal tubule occlusion and can be suggested as a effective treatment modality for patients with dentinal hypersensitivity. The objectives of the study were -to evaluate effectiveness of Fluoro calcium phospho silicate on dentinal tubules occlusion, to evaluate effectiveness of Fluoro calcium phospho silicate and laser and to compare its effect with Fluoro calcium phosphosilicate alone and laser on dentinal tubule occlusion, and to evaluate the effectiveness of laser on dentinal tubule occlusion. In study setting, SEM analysis was done at Sophisticated test and instrumentation centre, Cochin University of Science and Technology (CUSAT), Kerala. 120 Dentine specimens were obtained from sound premolars extracted for orthodontic purpose from the patients of age group 13 to 40 years. All the teeth were stored in 0. 2% thymol at room temperature. In our study, Fluoro calcium phospho silicate (Biomin) showed an average results of 70.37% completely occluded tubules and 23.48% of partially occluded tubules compared to 2.68% and 28.43% in the control group. Conclusion: In our invitro study the treated groups the specimens brushed with combination group (Biomin and Laser) showed the highest percentage of tubule occlusion followed by Biomin alone and then Laser. Hence from the results, it can be stated that combination of Biomin and laser can be considered as the best effective method in office treatment modality for dentinal hypersensitivity because of its ability to occlude more tubules..
 Keywords: Diode laser, Biomin or Elzenes

The Effect of Mesoporous Silica Nanoparticles Desensitizing Slurry Alone or Combined with Calcium Phosphate on Dentin Permeability (An in Scanning Electron Microscope study)

Purpose: Determining the dentinal tubules occlusion and permeability of desensitized dentin after its treatment with (MSN) slurry alone or combined with calcium phosphate (Ca2po4@MSN)versus (NHAp) suspension. Materials and Methods: eighty sound posterior teeth were extracted for orthodontic purpose. Dentin disks of 1 mm thickness were cut perpendicular to the long axis of the teeth at level of 1 mm above the cemento-enamel junction. All samples were treated with 6% citric acid solution for 2 minutes to stimulate sensitive teeth. The samples were divided into four main groups (30 each) according to the material used either Ca+2and PO4@ MSN slurry, slurry of MSN nanoparticles, NHAp suspension and no treatments a control group. These four groups were further subdivided into two groups according to time to after 1 day and after 4 weeks. In random samples from each group, the samples were evaluated for dentinal tubules occlusion using Environmental Scanning Electron Microscope and for dentin permeability. The samples were photographed using Stereomicroscope. Image analysis software was used for indicating degree of occlusion and the depth of dye penetration. The data were analyzed using two-way ANOVA and Turkey’s HSD test. The significance level was set at p ≤ 0.05. Results: There was significant difference observed between Ca2Po4 @MSN nanoparticles and NHAp compared to (MSN alone) group but there was insignificant difference between groups (Ca2Po4@MSN) and (NHAp) in dentinal tubules occlusion and permeability. Conclusion: (Ca2Po4@MSN), MSN alone and NHAp are valuable tools to enhance dentinal tubules occlusion and permeability of desensitizing dentin.

Analysis of an Herbal Ayurdantham Medicated Tooth liquid on Dentinal Tubule Occlusion using Scanning Electron Microscopy.

Background:Dentin hypersensitivity is described as “short sharp pain arising from exposed dentin in response to various stimuli typically thermal, evaporative, tactile, osmotic or chemical and cannot be ascribed to any other form of dental defect or disease.” Dentine hypersensitivity can be treated with various desensitizing agents ,where oral rinse has a promising effect in delivering the therapeutic effect all over the tooth surface including interproximal areas, as they can flow and reach areas where toothpastes are not much effective, hence the occlusion of dentinal tubules using Ayurdhantam medicated an herbal mouthwash was evaluated.Methodology:Twenty such dentinal blocks were obtained; the surfaces of each dentin block were polished using a silicon carbide disc for 30 s to create a basic smear layer. The smear layer is finally detached by applying 17% EDTA solution onto the dentin blocks for 5 min to ensure the patency of the dentinal tubules, following which they were rinsed with distilled water. The specimens were placed into the Ayurdhantam solution (medicated) for 2 min every day for 7 days. The specimens were stored in artificial saliva during the study. The specimens were analyzed under scanning electron microscope (SEM) for the occlusion of dentinal tubules.Results:SEM images showed the partial occlusion of the tubules and a large amount of smear layer.Conclusions:Based on this in vitro experiment carried out, it is shown that Ayurdhantam-medicated mouthwash can be used for treating dentine hypersensitivity effectively.

Association of Nd:YAG laser and calcium-phosphate desensitizing pastes on dentin permeability and tubule occlusion.

Objective To evaluate the efficacy of Nd:YAG laser associated with calcium-phosphate desensitizing pastes on dentin permeability and tubule occlusion after erosive/abrasive challenges.Methodology Dentin specimens were exposed to 17% ethylene diamine tetra-acetic acid (EDTA) solution for 5 min and randomly allocated into five groups: G1, control (no treatment); G2, Nd:YAG laser (1 W, 10 Hz, 100 mJ, 85 J/cm2); G3, Laser + TeethmateTM Desensitizer; G4, Laser + Desensibilize Nano P; and G5, Laser+Nupro®. Specimens underwent a 5-day erosion-abrasion cycling. Hydraulic conductance was measured post-EDTA, post-treatment, and post-cycling. Post-treatment and post-cycling permeability (%Lp) was calculated based on post-EDTA measurements, considered 100%. Open dentin tubules (ODT) were calculated at the abovementioned experimental moments using scanning electron microscopy and ImageJ software (n=10). Data were analyzed using two-way repeated measures ANOVA and Tukey’s test (α=0.05).Results G1 presented the highest %Lp post-treatment of all groups (p<0.05), without significantly differences among them. At post-cycling, %Lp significantly decreased in G1, showed no significant differences from post-treatment in G3 and G4, and increased in G2 and G5, without significant differences from G1 (p>0.05). We found no significant differences in ODT among groups (p>0.05) post-EDTA. At post-treatment, treated groups did not differ from each other, but presented lower ODT than G1 (p<0.001). As for post-cycling, we verified no differences among groups (p>0.05), although ODT was significantly lower for all groups when compared to post-EDTA values (p<0.001).Conclusion All treatments effectively reduced dentin permeability and promoted tubule occlusion after application.Combining Nd YAG laser with calcium-phosphate pastes did not improve the laser effect. After erosive-abrasive challenges, treatments presented no differences when compared to the control.

The effect of reduced glutathione on the toxicity of silver diamine fluoride in rat pulpal cells.

Introduction Due to its ability to arrest untreated dental caries, silver diamine fluoride (SDF) has been advocated for indirect pulp capping procedures. However, the high concentrations of silver and fluoride in SDF raise concerns about its biocompatibility to pulpal tissues.Objectives This study aimed to investigate the effect of SDF on the viability, alkaline phosphatase (ALP) activity, and morphology of pulpal-like cells (RPC-C2A) and to evaluate the influence of reduced glutathione (GSH) on SDF-induced cytotoxicity and deposit formation on dentin.Methodology The cytotoxicity of diluted 38% SDF solutions (10-4 and 10-5), with or without the addition of 5 mM or 50 mM GSH, was evaluated at 6 and 24 hours. Cell viability was detected using WST-8 and the effect on ALP activity was performed using an ALP assay kit. Cell morphology was observed using a phase-contrast microscope. Scanning electron microscopy analysis was conducted to evaluate the effect of GSH incorporation or conditioning on SDF-induced deposit formation on dentin discs. Cytotoxicity data were analyzed by two-way analysis of variance (ANOVA) and Tukey post hoc tests (p<0.05).Results There were significant differences between the groups. The results demonstrated that all tested SDF dilutions caused a remarkable cytotoxic effect, while the addition of GSH prevented SDF-induced damage at 6-hour exposure time in the higher dilution of SDF. Dentin treated with plain SDF or GSH-incorporated SDF solution showed deposit formation with occluded dentinal tubules, unlike the other groups.Conclusion SDF severely disturbed the viability, mineralization-ability, and morphology of pulpal-like cells, while controlled concentrations of GSH had a short-term protective effect against SDF-induced damage. GSH showed an inhibitory effect on SDF-induced dentinal deposit formation. Further research is warranted to evaluate the effect of GSH on caries-arresting, anti-hypersensitivity, and antibacterial functions of SDF.

Dentinal tubule occlusion using Er:YAG Laser: an in vitro study.

We analyzed the effects of the Er:YAG laser used with different parameters on dentinal tubule (DT) occlusion, intrapulpal temperature and pulp tissue morphology in order to determine the optimal parameters for treating dentin hypersensitivity. Dentin specimens prepared from 36 extracted human third molars were randomized into six groups according to the treatment method (n=6 each): control (A); Gluma desensitizer (B); and Er:YAG laser treatment at 0.5 W , 167 J/cm2 (50 mJ, 10 Hz) (C), 1 W , 334 J/cm2 (50 mJ, 20 Hz) (D), 2 W , 668 J/cm2 (100 mJ, 20 Hz) (E), and 4 W and 1336 J/cm2 (200 mJ, 20 Hz) (F). Treatment-induced morphological changes of the dentin surfaces were assessed using scanning electron microscopy (SEM) to find parameters showing optimal dentin tubule occluding efficacy. To further verify the safety of these parameters (0.5 W, 167 J/cm2), intrapulpal temperature changes were recorded during laser irradiation, and morphological alterations of the dental pulp tissue were observed with an upright microscope. Er:YAG laser irradiation at 0.5 W (167 J/cm2) were found to be superior in DT occlusion, with an exposure rate significantly lower than those in the other groups (P<0.05). Intrapulpal temperature changes induced by Er:YAG laser irradiation at 0.5 W (167 J/cm2) with (G) and without (H) water and air cooling were demonstrated to be below the threshold. Also, no significant morphological alterations of the pulp and odontoblasts were observed after irradiation. Therefore, 0.5 W (167 J/cm2) is a suitable parameter for Er:YAG laser to occlude DTs, and it is safe to the pulp tissue.

Biomimetic oligopeptide formed enamel-like tissue and dentin tubule occlusion via mineralization for dentin hypersensitivity treatment.

Dentin hypersensitivity (DH) is a common oral disease with approximately 41.9% prevalence. Reconstruction of dental hard tissues is the preferred treatment for relieving DH. Here, we applied biomineralization method using oligopeptide simulating cementum protein 1 (CEMP1) to regenerate hard tissues on demineralized dentin. The self-assembly and biomineralization property of the oligopeptide were detected by scanning electron microscopy (SEM), circular dichroism spectroscopy, and transmission electron microscopy. Oligopeptide's binding capacity to demineralized dentin was evaluated by SEM and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Remineralization was characterized using SEM, ATR-FTIR, X-ray diffraction, and nanoindentation. Oligopeptide's biocompatibility was evaluated using periodontal ligament cells. Oligopeptides self-assembled into nano-matrix and templated mineral precursor formation within 24 h. Moreover, oligopeptide nano-matrix bound firmly on demineralized dentin and resisted water rinsing. Then, bound nano-matrix served as a template to initiate nucleation and transformation of hydroxyapatite on demineralized dentin. After 96 h, oligopeptide nano-matrix regenerated an enamel-like tissue layer with a thickness of 15.35 μm, and regenerated crystals occluded dentin tubules with a depth of 31.27 μm. Furthermore, the oligopeptide nano-matrix had good biocompatibility when co-cultured with periodontal ligament cells. This biomimetic oligopeptide simulating CEMP1 effectively induced remineralization and reconstructed hard tissues on demineralized dentin, providing a potential biomaterial for DH treatment.

Acidic Monetite Complex Paste with Bleaching Property for In-depth Occlusion of Dentinal Tubules.

BackgroundDentin hypersensitivity (DH) is a common dental clinical condition presented with a short and sharp pain in response to physical and chemical stimuli. Currently no treatment regimen demonstrates long-lasting efficacy in treating DH, and unesthetic yellow tooth color is a concern to many patients with DH.AimTo develop a bi-functional material which can occlude dentinal tubules in-depth and remineralize dentin for long-lasting protection of the dentin–pulp complex from stimuli and bleach the tooth at the same time.MethodsA mixture containing CaO, H3PO4, polyethylene glycol and H2O2 at a specific ratio was mechanically ground using a planetary ball. The mineralizing complex paste was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Dentin was exposed to the synthesized paste for 8 h and 24 h in vitro. The mineralizing property was evaluated using SEM and microhardness tests. Red tea-stained tooth slices were exposed to the synthesized paste for 8 h and 24 h in vitro. The bleaching effect was characterized by a spectrophotometer.ResultsThe complex paste had very a fine texture, was injectable, and had a gel-like property with 2.6 (mass/volume) % H2O2 concentration. The X-ray diffraction pattern showed that the inorganic phase was mainly monetite (CaHPO4). The mineralizing complex paste induced the growth of inorganic crystals on the dentin surface and in-depth occlusion of dentin tubules by up to 80 μm. The regenerated crystals were integrated into the dentin tissue on the dentin surface and the wall of dentinal tubules with a microhardness of up to 126 MPa (versus 137 Mpa for dentin). The paste also bleached the stained dental slices.ConclusionThe mineralizing complex paste is a promising innovative material for efficient DH management by remineralizing dentin and in-depth occlusion of dentin tubules, as well as tooth bleaching.

Efficient removal of 2,6-xylidine precipitate using different agitation protocols: An in vitro field emission scanning electron microscopic study.

Background:Any solution of chemical nature when combined will result in the formation of a precipitate, which in the root canal system will interfere with the hermetic seal. In clinical practice presence of any precipitate, especially carcinogenic in nature, should be eliminated.Aim:To evaluate whether final irrigation with different agitation protocols will remove the precipitate formed following lidocaine hydrochloride and sodium hypochlorite combination at the coronal, middle, and apical-root thirds.Materials and Methods:Forty-four uniradicular teeth were standardized at 17 mm. All specimens were injected with 2% lidocaine hydrochloride and 2.5% sodium hypochlorite, followed by mechanical instrumentation using rotary files. Further, specimens were arbitrarily divided into four groups (n = 11) based on the final irrigation protocol: Group 1: No irrigation; Group 2: Manual irrigation; Group 3: Mechanical irrigation; Group 4: Ultrasonic irrigation. Samples were sectioned and Field Field Emission Scanning Electron Microscopic (FESEM) analysis of the canal wall was done at coronal, middle, and apical thirds.Results:FESEM images revealed occluded dentinal tubules with the presence of precipitate seen in all-thirds of each specimen.Conclusion:No irrigation protocol was successful in removing the precipitate formed; but when compared ultrasonic irrigation had the least precipitate seen at-coronal,-middle and apical thirds.

Physical and Chemical Characterizations of Novel Bioactive Caries Detecting Solution

Introduction: The nature and progression of acute and chronic carious lesion are extremely variable on different tooth surfaces. Early detection of dental caries is challenging for clinicians and involves careful visual and tactile examination. Caries detection dyes and chemomechanical caries removal solutions guide the clinicians in the removal of infected dentin. This study aims to prepare and analyze the physical, chemical, and thermal characterizations of novel bioactive caries detecting dye solution (BCD) and its effectiveness in caries removal from the tooth structure. Materials and Methods: BCD is a combination of contrast agent (iobitridol), chitosan (CS), nanohydroxyapatite (nHAP), and coloring agent. It is synthesized, lyophilized, and subjected to Fourier transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimeter (DSC) analysis. Pilot study was conducted by applying BCD on two extracted carious teeth for evaluating caries removal efficiency under a microscope (10x). Scanning electron microscopy (SEM) image analysis was done to assess the percentage of dentinal tubules occlusion. Results: FTIR, XRD, and DSC analysis revealed that BCD has compatible interfacial bond between the components and is endothermic. Effective caries removal was seen under a microscope and SEM analysis revealed mean 77.66% of dentinal tubules occlusion. Conclusion: BCD is a stable solution without exothermic reaction, has caries identifying potential, and helps in caries removal. BCD is also bioactive in nature due to the presence of CS and nHAP as ingredients.

Bioactive glass versus Arginine dentifrices on the reduction of dentin permeability and acid tolerance.

ObjectivesTo compare the efficacy of calcium sodium phosphosilicate (CSPS) and arginine dentifrices on dentin permeability and acid tolerance.Material and MethodsSixty dentin discs were randomly assigned into 3 groups, then brushed for 1 min with CSPS, arginine, or fluoride (control) dentifrices. To test acid tolerance, each disc was soaked in 6% citric acid for 1 min. Dentin permeability was measured before, following brushing, and acid challenge. Ten discs per group were similarly treated and evaluated for tubule occlusion following a single dentifrice application, while other five discs per group were employed in an acid tolerance assay.ResultsThe percentage reduction in dentin permeability was 39.26%, 32.27%, and 21.71% in the arginine, CSPS, and control groups, respectively. The differences in dentin permeability reduction between the arginine and CSPS groups following brushing and acid challenge were not significant (p = 0.398 and p = 0.211, respectively). The arginine dentifrice demonstrated a significant reduction in permeability compared with the control (p = 0.011). In addition, the occlusion exhibited by the arginine and CSPS dentifrices was more resistant to acid challenge compared with that of the control (p < 0.001). From SEM analysis, dentinal tubule occlusion was observed after a single application in all groups. Some open dentinal tubules were detected in the test groups, while almost all of the orifices were open in the fluoride group following acid challenge.ConclusionsThere is no significant difference between arginine and CSPS dentifrices in reducing dentin permeability following a single application and acid challenge. Following acid challenge, the reduced permeability generated by arginine and CSPS was more stable compared with the fluoride dentifrice.

In vitro SEM analysis of desensitizing agents and experimental hydroxyapatite-based composition effectiveness in occluding dentin tubules.

Novel materials used for dentin hypersensitivity (DH) treatment, including hydroxyapatite-based desensitizers, are not only effective in occluding dentinal tubules, but are also biocompatible and non-toxic. A newly formulated desensitizer containing hydroxyapatite was evaluated in comparison to commercially available desensitizers. To compare the occluding efficacy and durability of 3 commercially available desensitizing agents with a pharmaceutical composition developed by the authors based on hydroxyapatite (HAp). For the experiment, 40 disc-shaped dentin specimens (5 mm thick) were obtained from extracted human teeth. Each disc was divided into 4 sections, so that each desensitizing agent could be applied to each specimen and prepared for further evaluation in most homogenous conditions. The chemical composition of the dentin surfaces was analyzed using scanning electron microscopy (SEM) equipped with an energy-dispersive X-ray spectroscope (EDS), Fourier-transform infrared (FTIR) and Raman spectra techniques. The specimens were immersed in an artificial saliva solution for 24 h, 48 h and 7 days to assess the durability of the layers and the tubule-obliteration effectiveness. Data analysis was performed using Student's t-test with an average value of normal distribution at an unknown variance with a standard deviation (SD) of σ-0.4. All the test groups showed some degree of dentinal tubule occlusion or a covering layer, but the HAp-based composition proved to be the longest-lasting. It was concluded that the developed pharmaceutical composition creates a coating on the dentin surface built of hydroxyapatite crystals sized 10-20 μm, which are likely to constitute a reservoir of calcium and phosphate ions, as well as smaller crystals (0.2-0.3 μm) that occlude dentinal tubules. The composition containing biocompatible hydroxyapatite effectively occluded dentinal tubules and therefore exhibits a potential for reducing the pain and discomfort caused by dentin hypersensitivity.

Doxycycline-functionalized polymeric nanoparticles inhibit Enterococcus faecalis biofilm formation on dentine.

To evaluate in a laboratory setting the antimicrobial properties and the potential to inhibit biofilm formation of novel remineralizing polymeric nanoparticles (NPs) when applied to dentine surfaces and to ascertain the effect of the functionalization of these NPs with zinc, calcium or doxycycline. The antimicrobial activity and inhibition of biofilm formation of polymeric NPs were analysed on human dentine blocks that were infected with Enterococcus faecalis before or after application of NPs. LIVE/DEAD ® testing under Confocal Laser Scanning Microscopy and bacterial culturing were employed to analyse biofilm biovolume and bacterial viability. Field Emission Scanning Electron Microscopy was also employed to assess biofilm morphology. One-way anova with Welch's correction and post hoc comparison by the Games-Howell test were performed for comparisons between groups. The un-functionalized NPs displayed the greatest antimicrobial activity against E.faecalis biofilms as they provided the lowest biovolume (3865.7±2926.97µm3 ; P<0.001) and the highest dead/injured cells percentage (79.93±18.40%; P<0.001), followed by Dox-NPs (biovolume: 19,041.55±17,638.23µm3 , dead/injured cells: 45.53±26.50%; P<0.001). Doxycycline-loaded NPs had the largest values of inhibition of biofilm formation with the lowest biofilm biovolume (8517.65±7055.81µm3 ; P<0.001) and a high dead/injured bacterial percentage (68.68±12.50%; P<0.001). Un-functionalized NPs did not reduce biomass growth (P>0.05), but attained the largest percentage of compromised cells (93±8.23%; P<0.001), being able to disrupt biofilm formation. It also produced occlusion of dentinal tubules, potentially interfering with bacterial tubule penetration. A new generation of bioactive nano-fillers (doxycycline-functionalized polymeric NPs) had antibacterial activity and occluded dentinal tubules. Incorporating these NPs into endodontic sealers may have the potential to enhance the outcome of root canal treatment.

Quantitative assessment of dentine mineralization and tubule occlusion by NovaMin and stannous fluoride using serial block face scanning electron microscopy

Dentine hypersensitivity (DH) is one of the most common dental conditions affecting most adults during their lifetime. Tubule occlusion is a widely accepted method for treating DH. Current in-vitro techniques such as focused ion beam, scanning electron microscopy (SEM), or hydraulic conductance that are used to determine tubule occlusion do not provide the depth of occlusion, are time-consuming, expensive and the volume of dentine tested is limited. The presented study aimed to assess the ability of serial block-face SEM (SBF-SEM) to section dentine, to quantify the number of occluded tubules including the depth of penetration by NovaMin and stannous fluoride (SnF2 ) and to compare mineral density between the control and treated dentine. Results demonstrated that NovaMin provided a better occlusion with 100% of the tubules blocked at the surface compared to 83% for SnF2 . The grayscale value (230.42) was significantly higher (p ≤ 0.05) after treatment with NovaMin compared to SnF2 (222.06) and the control (196.37), indicating increased mineral density and dentine mineralization. SBF-SEM has the potential to be used for large volume analysis of bone-like materials at high resolution with minimal sample preparation over a short period. It can be significantly useful in the development and research of new biomaterials.

An in vitro analysis of the effect of adjunctive use of ozonated oil with a desensitizing agent on dentinal tubule occlusion

IntroductionDentinal hypersensitivity (DH), is a commonly encountered clinical problem, the management of which is by two main approaches that involve blockage of nerve activity and tubular occlusion. Desensitizing agents containing arginine and calcium carbonate have emerged effective in occluding tubules. Ozone removes the smear layer and opens up the dentinal tubules for easy penetration of these desensitizing agents. ObjectiveTo comparatively evaluate the effect of ozonated oil on the patency and occlusion of dentinal tubules with and without adjunctive application of a desensitizing agent containing arginine. Materials and methods80 dentin specimens that were distributed into 4 groups as Group 1 (control), Group 2 (ozonated oil), Group 3 (desensitizing agent) and Group 4 (desensitizing agent following the application of ozonated oil), underwent an acid challenge. Scanning electron microscopic (SEM) images of the dentin specimens were obtained prior to any treatment, after the application of the therapeutic agents and after acid challenge and mean tubule occlusion scores were recorded in each case employing a suitable scoring system. The statistical analysis employed One-way ANOVA test followed by Tukey's Post hoc test and Student Paired t-test for intergroup and intragroup comparisons of the mean tubule occlusion scores respectively. ResultsGroup 2, treated with ozonated oil alone showed a statistically significant increase in the number of open dentinal tubules. Group 4 showed more compact deposits of desensitizing agent and more densely occluded tubules as compared to Group 3 which was more retained in the former even after acid challenge. ConclusionAdjunctive application of the desensitizing agent containing arginine, with ozonated oil has a synergistic effect, where the latter causes opening of dentinal tubules allowing more compact penetration of the former and thus may be a potentially more effective treatment approach in the management of DH.

Scanning electron microscopic analysis of interaction between 2% lidocaine hydrochloride (with adrenaline) with 3% sodium hypochlorite and 2% chlorhexidine on root canal dentin after Chemomechanical instrumentation: An in vitro study

Introduction: To investigate the effect of resultant precipitate formed on interaction between 2% lidocaine hydrochloride (with adrenaline) (LA) with 3% sodium hypochlorite (NaOCL) and 2% chlorhexidine (CHX) on root canal dentin after chemomechanical preparation using scanning electron microscopy (SEM). Methods: Thirty six mandibular premolars were decoronated, and the root length was standardized. All specimens were randomly distributed into the following three groups: Group I (control): 2% LA mixed with sterile water. Group II: 2% LA with 3% NaOCL, Group III: 2% LA with 3% CHX. In all groups mechanical instrumentation with rotary files was done. Teeth samples were sectioned into three parts, split and SEM analysis of root canal wall was done at cervical. Middle, and apical root thirds. Results: SEM images revealed patent dentinal tubules with no precipitate occlusion in group I and group III, whereas there was occlusion of dentinal tubules with a precipitate in group II at all the three root levels studied. Conclusions: The precipitate formed on the interaction between 2% LA solution with 3% NaOCL tends to occlude the dentinal tubules at the coronal, middle, and apical root thirds. The chemomechanical rotary instrumentation procedure did not effectively remove the precipitate from all the three root levels of the specimens studied. LA/sterile water group and LA/CHX group did not result in any precipitate formation on root canal dentin.

Synthesis of Calcium Phosphate Composite Bioactive Oleic Acid-Based Gels and its Application for Dentine Tubule Occlusion

Dentine hypersensitivity (DH) is a common issue among humans caused by the erosion of tooth enamel as a result of chewing and brushing incorrectly. The most effective treatment method is occluding the exposed dentine tubules. Because calcium phosphate is an important mineral and the most common mineral for dentine and orthopaedic application, this study focuses on the synthesis of bioactive gels containing calcium phosphate nanoparticles. The synthesis is performed using water-in-oil emulsion and characterized by the use of TGA, Rheological, TEM, and SEM techniques. This method used oleic fatty acids as an external phase and Tween 20 as surfactant to form water-in-oil nanodroplets. Gelatine was used to form the substance into a gel and increase its stability. The resulting nanoparticles had the same spherical shape and a similar size. Therefore, the varying amounts of gelatin do not affect the particle size. However, viscoelastic properties of gels were found to be changed. The ability of the gel for dentine tubule occlusion was investigated using SEM techniques. After 1 day, it was found that the gels can occlude dentine tubules.