Dentinal Tubules Research Articles

Effects of Mechanized Irrigation Protocols on Endodontic Obturation Using Calcium Silicate-Based Sealer

The aim of this study was to evaluate the effects of mechanized final irrigation protocols (XPE, XP-Endo Finisher; XPC, XP-Clean; and ECL, Easy Clean) compared to PUI (passive ultrasonic irrigation) on the debris incidence and open dentinal tubules, and their effects on the adhesion interface after 48 h and 6 months. One hundred twenty maxillary central incisors were submitted to chemical–mechanical preparation using a rotary instrument and 2.5% sodium hypochlorite. Specimens were distributed in 4 groups (n = 30) in accordance with the mechanized final irrigation protocol: XPE, XPC, ECL, or PUI. Forty specimens (n = 10/group) were submitted to SEM analysis to evaluate the residue incidence and dentin open tubules. The other specimens were obturated using Bio-C Sealer and submitted to push-out bond strength and adhesive failure mode evaluations in the cervical, middle, and apical thirds after 48 h or 6 months (n = 10/group). Only in the apical third, ECL presented the highest residue incidence and fewer open dentinal tubules when compared to the XPE, XPC, and PUI groups (p < 0.05). In the cervical and middle root thirds, no significant differences were observed regardless of the group evaluated (p > 0.05). After 48 h, ECL resulted in the lowest bond strength only in the apical third (p < 0.05), while the XPE, XPC, and PUI groups remained similar in the cervical and middle thirds (p > 0.05). At 6 months, all groups showed lower bond strength values regardless of the root third evaluated, but ECL showed the lowest bond strength in the apical and middle root thirds when compared to the other groups (p < 0.05). The ECL protocol did not provide adequate residue removal on the apical radicular third and negatively affected the longevity of endodontic obturation using a calcium silicate-based sealer.

Gelatin-Modified Bioactive Glass for Treatment of Dentin Hypersensitivity

When dentin is directly exposed to the oral cavity for various reasons, such as a lack of enamel on the tooth surface, external stimuli to the dentin often cause transient discomfort known as dentin hypersensitivity. In order to block the incoming stimulus signal, an ideal treatment is to induce the production of minerals to block the dentinal tubules. In this work, a dentin-desensitizing plugging material was prepared by modifying mesoporous bioactive glass with gelatin, the mineralization and desensitization effects of which were compared with Gluma in in vitro experiments. These experiments confirmed that gelatin-modified bioactive glass (MBG@PDA@Gel) is more effective than traditional desensitizing agents at blocking dentin tubules. Following the successful synthesis of MBG@PDA@Gel, as confirmed by scanning electron microscopy, transmission electron microscopy, and other tests, the treatment of demineralized dentin with MBG@PDA@Gel demonstrated that the dentinal tubules were tightly blocked under scanning electron microscopy. MBG@PDA@Gel induces minerals in deeper layers of dentinal tubules, promoting remineralization and forming a unified structure with the tubule blockage. Animal studies showed that MBG@PDA@Gel can remineralize demineralized dentin, and it is stable in the oral cavity and does not fall out. MBG@PDA@Gel not only enhances the biocompatibility of the nanoparticle but also results in an overall uniform and rapid remineralization of the demineralized dentin.

Dentinal Tubule Occlusion and Dentin Permeability Efficacy of Silver Diamine Fluoride Solutions.

This invitro study compared the effect of two commercially available silver diamine fluoride (SDF) products on dentinal tubule (DT) occlusion and dentin permeability. Sixty-six dentin discs (1.0 mm thick) were divided equally into six groups: acid-etched with no treatment (negative control-NC), etched and sealed with nail varnish (positive control-PC), non-etched and treated with Advantage Arrest (AA), non-etched and treated with Topamine (TP), etched and treated with AA, and etched and treated with TP. Eight specimens from each group were tested for permeability using the dye percolation method. The remaining three samples from each group were assessed for dentinal tubule occlusion, depth of SDF penetration, and elemental analysis using a scanning electron microscope coupled with an energy-dispersive X-ray (SEM/EDX) system. One-way ANOVA and Tukey's post hoc test were used to analyze the results. TP exhibited lower (p < 0.05) dye percolation compared to AA. While both SDF materials showed a statistically similar (p > 0.05) penetration depth in the DT, none of them had the ability to completely occlude all the DTs. AA exhibited more silver and fluoride ion deposition on etched dentin than TP, and both materials showed a similar increase in the deposition of Ca and P compared to NC. Whereas the effectiveness of dentin tubule (DT) occlusion varies based on the material used, both tested SDF products exhibit the capability to seal dentinal tubules, decrease dentin permeability, and promote dentin remineralization. These findings suggest their potential advantage in managing dentin hypersensitivity.

Sealing Ability of Bioceramic Sealer after Ultrasonic Activation of Different Root Canal Irrigating Solutions

Aim To evaluate and compare the sealing ability of bio ceramic root canal sealer after ultrasonic activation of root canal irrigation solutions 3% NaOCl , 40% Citric acid &amp; Neem leaf extract .  Materials and Methods In this study, 42 mandibular premolar teeth with single roots and canals were divided into three groups for irrigation: 3% NaOCl, 40% citric acid, and Neem leaf extract. After access preparation and glide path creation with a #10 K-file (0.02 taper), the canals were instrumented using a crown-down technique to an ISO size of 30, with saline as the irrigant. Ultrasonically activated irrigation was used, followed by saline in all groups. The canals were obturated with Dentsply Gutta- percha and Bio C sealer, 1mm short of the working length, and sealed with temporary restorations. Teeth were incubated at 37°C for 3 days, and horizontal sections at 3mm from the apex were taken. Confocal laser scanning microscopy measured sealer penetration, and statistical analysis was conducted to compare results between groups.  Results The results suggest that 40% citric acid is the most effective irrigant for enhancing sealer penetration into dentinal tubules at the apical third, both in terms of percentage and depth of penetration, compared to 3% NaOCl and neem leaf extract. This indicates that citric acid may improve the sealing ability of root canal treatments more effectively than the other tested irrigants.  Conclusion The results suggest that 40% citric acid is the most effective irrigant for enhancing sealer penetration into dentinal tubules at the apical third, both in terms of percentage and depth of penetration, compared to 3% NaOCl and neem leaf extract. This indicates that citric acid may improve the sealing ability of root canal treatments more effectively than the other tested irrigants.

In vitro study of the treatment of dentin hypersensitivity with gallic acid combined with sodium fluoride

BackgroundDentin hypersensitivity (DH) is a common oral condition that is associated with severe dental pain. Pain relief is a key focus of the treatment of DH. The purpose of this study was to evaluate the blocking and antacid effects of gallic acid (GA) combined with sodium fluoride (NaF) on dentinal tubules in vitro.MethodsNinety dentin discs from human third molars were treated with 6% citric acid for 2 min. Then, the surface morphologies of ten dentin discs were observed by scanning electron microscopy (SEM). The remaining samples were randomly divided into four groups: the NaF group, which was treated with 1000 ppm NaF; the GA group, which was treated with 4000 ppm GA; the GA + NaF group, which was treated with 1000 ppm NaF + 4000 ppm GA; and the blank group, which was treated with deionized water. The dentin permeability of each sample was measured with a water-filled system before processing and after 7 days of treatment. Dentin morphology and surface deposits were observed by SEM. Then, samples from the NaF, GA + NaF and blank groups were subjected to an acid challenge by incubation with 0.02% citric acid for 2 min. SEM and a water-filled system were used to evaluate the blocking and antacid effects of NaF and GA + NaF.Results1. NaF and GA + NaF significantly decreased dentin permeability. The effect of the GA + NaF treatment was more significant. After acid challenge, both groups still exhibited decreased dentin permeability compared with the initial assessment. 2. Compared with the NaF group, the GA + NaF group had more mineral deposits on the dentin surface and dentin tubules. After acid challenge, the deposits in the GA + NaF group were still clearly visible.ConclusionThe combined effect of GA and NaF on reducing dentin permeability by blocking open dentin tubules is better than that of NaF alone. After acid challenge, the GA + NaF treatment still had a better effect.

Fabrication of Rapidly Soluble Zn2+-Releasing Phosphate-Based Glass and Its Incorporation into Dental Resin

Phosphate-based glasses are known for their excellent biocompatibility and adjustable degradation rates. In this study, we fabricated a rapidly soluble zinc-ion-releasing phosphate-based glass (RG) specifically designed for use in dental cavity liners. The aim of this study was to evaluate the ion-releasing properties and antibacterial effects of RG. Additionally, a dental resin incorporating RG was fabricated to serve as a cavity liner, and its effectiveness was investigated in vitro. The RG formulation exhibited high solubility and released high concentrations of Zn2+ at various pH values. To assess the antibacterial properties of RG, six bacterial species detected in deep carious regions were incubated in the presence of RG. In vitro antibacterial testing against six bacterial species revealed that RG exhibited strong bactericidal effects against these prevalent bacteria. Furthermore, using a dentin model infected with Lactobacillus casei or Streptococcus mutans, the experimental resin containing RG demonstrated an effective bactericidal effect in the dentinal tubules, highlighting its potential as a promising material for cavity liners or pulp-capping applications.

An In Vitro Comparative Analysis of Physico–Mechanical Properties of Commercial and Experimental Bioactive Endodontic Sealers

This study aimed to evaluate the fracture resistance of root and sealer penetration after obturation using an epoxy resin sealer AH plus (AH+) and two different bioactive endodontic sealers, i.e., Totalfill BC Hiflow (TF BC), and experimental injectable bioactive glass (Exp.BG). A thermo-sensitive injectable sealer was prepared by using a non-ionic triblock copolymer and bioactive glass. The root canals of human extracted teeth were obturated with the respective sealers. The fracture resistance was analyzed at different time intervals, i.e., days 7, 30, and 90. The morphological and elemental analyses of the fractured roots were conducted with a scanning electron microscopy and a electron dispersive spectroscopy. Sealer penetration depth and the percentage of penetrated sealers into the dentinal tubules were assessed with the confocal laser scanning microscope. Statistical analysis was performed using a one-way ANOVA post hoc Tukey’s test. The mean fracture force in AH+ was significantly higher on day 30 (664.08 ± 138.8 N) compared to day 7 (476.07 ± 173.2 N) and day 90 (493.38 ± 120.18 N). There was no statistically significant difference between the TF BC and Exp.BG at different time intervals. The maximum penetration was observed in the middle region compared to coronal and apical for the Exp.BG, followed by the TF BC and AH+ groups; however, a nonsignificant difference in penetration was found over time. It is concluded that the TF BC group showed overall better fracture resistance than AH+ at day 90. Exp.BG showed comparable sealer penetration to those of TF BC and better than those of AH+.

The comparative study of temperature rise, time consuming and cut quality among piezosurgery, conventional rotary instruments and Er: YAG laser in apicectomy

ObjectivesThis study aimed to compare the temperature rise, time consuming and cut quality of apicectomy using three different methods.Materials and methodsTwenty-four single-rooted teeth were collected and divided into four groups operating apicectomy with a NINJA tip of a piezoelectric device (G1), a diamond bur with 300,000 rpm (G2), and Er: YAG laser at 200 mJ/ 30 Hz (G3) as well as 250 mJ/ 30 Hz (G4). The temperature elevation and time were recorded and the cut quality was evaluated via stereomicroscope and scanning electronic microscopy (SEM).ResultsThe temperature increases for G1 was significantly higher than for G2. However, there was no significant difference between G1 and G2 with laser groups respectively. The median time for apicectomy was: 100.14s for G1, 22.65s for G2, 33.58s for G3, and 21.80s for G4. G1 is the most time-consuming group and there was no statistically significance in the comparisons with G2, G3 and G4. Cut quality was assessed by crack occurrence, smear layer formation and dentinal tubules exposed. The percentage of cracked teeth in G1 and G2 was 33.33% and for laser groups the percentage was 16.67% each. SEM showed that no smear layer formed and almost all dentinal tubules were exposed on resected surfaces for G3&G4, surfaces from G2 were partly covered by smear layer, and surfaces from G1 were fully covered by smear layer and with no dentinal tubules exposed.ConclusionsEr: YAG laser and conventional rotary instruments were safe and efficient for apicectomy and with a better cut quality when compared with piezoelectric equipment. Er: YAG laser could be a promising technique for apicectomy and further studies are necessary, especially larger sample in vivo investigations, to verify the feasibility of Er: YAG laser in endodontic surgery.

BADT and Dentinal Tubules promote quality education to Congress delegates

BADT and Dentinal Tubules promote quality education to Congress delegates

Effects of Acid Etching on the Microstructure and Stiffness of Human Teeth

Abstract The mechanical properties of acid-etched enamel and dentin are important for understanding tooth erosion and developing innovative dental restorative materials. In this study, the microstructure and mechanical properties of both enamel and dentin were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM) to quantify the impact of acid etching. SEM images demonstrated that enamel rods have a diameter of approximately 5 μm, while dentinal tubules have a diameter of around 2 μm. After acid etching, the intertubular and peritubular regions were exposed, with the peritubular regions showing a thickness of approximately 1 μm. AFM measurements showed that the stiffness of enamel at the bottom, middle, and top layers is 26.28±4.24 GPa, 32.03±8.68 GPa, and 23.94±3.53 GPa, respectively. For dentin, the stiffness is 16.28±2.76 GPa at the bottom layer and 17.59±5.33 GPa at the middle layer. AFM morphology and stiffness maps illustrated the microstructures of enamel rod and sheaths, as well as dentin tubules in both unetched and acid-etched tooth sections. The stiffness of the acid-etched enamel rod and peritubular dentin decreased by 7-fold and 3.6-fold, respectively, compared to the unetched enamel rod and peritubular dentin.

Impact of Tulsi extract on sealer penetration in dentinal tubules as compared to 17% EDTA as the final root canal irrigant (in vitro analysis)

Introduction: Penetration of endodontic sealers into dentinal tubules is essential for ensuring successful root canal treatment by creating a hermetic seal that prevents reinfection. Traditionally, 17% EDTA has been used as the final irrigant for smear layer removal. However, concerns regarding its limited antimicrobial properties and potential for dentin erosion have prompted the exploration of alternative solutions. This in vitro study compared the effectiveness of Tulsi extract with that of 17% EDTA in promoting sealer penetration within the dentinal tubules. Methodology: Thirty extracted single-rooted teeth were randomly divided into three groups: Group 1, 17% EDTA; Group 2, Tulsi extract; and Group 3, saline control. After preparation, the root canals were irrigated with their respective soluti ons, filled with gutta-percha, and sealed with a calcium hydroxide-based sealer. Sealer penetration was analyzed using scanning electron microscopy (SEM) at the 2 mm and 5 mm levels from the root apex. Results: The results showed no significant difference in sealer penetration at 2 mm among all the groups. However, at 5 mm, both EDTA and Tulsi groups exhibited significantly greater sealer penetration than the control group (p &lt; 0.001). No significant difference was observed between the EDTA and Tulsi groups at 5 mm (p = 0.706). Conclusion: Tulsi extract demonstrated similar efficacy to 17% EDTA in facilitating sealer penetration, suggesting its potential as a biocompatible and antimicrobial alternative for root canal irrigation protocols. Further studies are warranted to explore its clinical applications and commercial viability.

NANOTECHNOLOGY IN DENTISTRY: DIAGNOSTICS AND TREATMENT

The rapid development of nanotechnology in medicine and dentistry has led to an exponential increase in the scope of research in this area. Aspects of nanotechnology that have already brought benefits include advanced drug delivery platforms, molecular imaging, and the development of treatment materials in dental practice. The aim of the research. To investigate the current possibilities of using nanotechnology in dentistry for diagnosis and treatment. Materials and methods of the research. The materials were used scientific publications by authors conducting their scientific and practical research in the field of dentistry and nanotechnology. The search was conducted in the scientometric databases PubMed, Scopus, Web of Science, Google Scholar using the terms “nanoparticles”, “oral cavity”, “nanomaterials”, “nanodentistry”, “diseases”, “biomaterials”, “treatment”, “diagnostics”. The research was conducted using such scientific methods as theoretical generalization and grouping, formalization, analysis, synthesis, and generalization of the results. The search resulted in the selection of publications for the period 2019-2024 that studied nanotechnology and its application in dental practice in diagnosis and treatment and will be discussed in this review. Results. The article shows a unique feature of nanotechnology, which is that the properties of a material at the nanoscale can differ from those at the macro level. This can be explained by two reasons: first, nanomaterials have a large surface area to volume ratio, which causes their high reactivity and, accordingly, affects their mechanical and electrical properties. Secondly, at the nanoscale, quantum effects dominate the material's behavior, giving rise to interesting observations of its electromagnetic and optical properties. Knowing the beneficial aspects of nanomedicine, scientists are trying to use nanotechnology to diagnose, treat and prevent dental diseases. Nanotechnology is used for sensitive medical procedures. They also demonstrate successful and useful applications for precise pain management, tooth restoration, and reduction of tooth hypersensitivity. Nanomaterials can plug open dentinal tubules, improving patient comfort and overall oral health. Orthodontic therapy has also been revolutionized by nanomaterials with shape memory properties, which enables faster and more efficient tooth movement. The development of revolutionary products and therapeutic alternatives is supported by ongoing research efforts, enabling the creation of dental implants, fillings and prostheses that closely mimic the characteristics of natural teeth. Nano-delivery systems are being developed to deliver drugs precisely into the oral cavity, providing optimal therapeutic outcomes with minimal side effects. This review highlights the multifaceted aspects of nanomedicine and how nanotechnology is proving to be useful in the diagnosis and treatment of dental diseases. The integration of nanotechnology into dentistry represents a groundbreaking evolution that goes beyond conventional oral care methods, allowing for the development of innovative diagnostic methods and improved oral health. Prospects for further research. Nanotechnology has revolutionized dentistry by changing the way oral care is conceptualized, delivered, and maintained. To develop effective methods for the diagnosis and treatment of dental diseases, it is necessary to continue research on the optimization of the mechanical properties and cytotoxicity of dental composite materials based on nanotechnology.

The investigation of endodontic irrigants and polyhexanide-based solution action on smear layer

AIM. The effect of irrigants on the smear layer on the intracanalicular dentin surface is one of the important issues in endodontics. The objective of this article is to determine the effect of different concentrations of polyhexanide-based solutions and standard irrigants on the smear layer using scanning electron microscopy (SEM).MATERIALS AND METHODS. The present study was conducted on 42 extracted teeth (third molars, first and second premolars) with formed apices that had been extracted for orthodontic indications. The teeth were decoronated and samples were prepared. In order to create a smear layer, the lumen of the canals was instrumented with H-file #40 throughout. A simulation of root canal irrigation was conducted by immersing the specimens in a 5-ml container filled with the proper solution for 1 hour: group 1 – no treatment (n = 6); group 2 – saline (n = 6); group 3 – 2% chlorhexidine (n = 6); group 4 – 3% sodium hypochlorite (n = 6); group 5 – 17% EDTA; group 6 – polyhexanide 0.1% (n = 6); group 7 – polyhexanide 0.2% (n = 6). A ~30 nm thick platinum film was sputtered onto the surface of each sample using a magnetron deposition technique. SEM microphotos were acquired on a Vega3 TESCAN scanning electron microscope (SEM) with an SE secondary electron detector, which enables imaging with high topographic contrast. The initial detector (incamera) was employed for image acquisition, with an electron energy of 30 keV. Images were acquired at magnifications of x20 (overview image), x150, x250, x500, x1000, x2500, x7500 for each sample.RESULTS. The samples from groups 1 and 5 demonstrated the absence of a smear layer on the dentin surface and the absence of smear plugs in the dentinal tubules. Groups 2 and 3 are distinguished by the deposition of a pronounced amorphous smear layer and the obturation of all dentinal tubules. Groups 4, 6, and 7 are distinguished by the deposition of a smaller volume of smear layer on the dentin surface, as well as the presence of semi-open or completely open entrances to the dentinal tubules.CONCLUSION. The data obtained indicates that antiseptic compositions based on polyhexanide in concentrations of 0.1 and 0.2% do not have a pronounced effect on the smear layer. However, in visual evaluation of SEM micrographs, their effect is comparable to that of 3% sodium hypochlorite. In instances where enhanced dissolution of the smear layer and smear plugs from the tubules is necessary to facilitate decontamination of the wall dentin, the combination of antiseptics with chelate compounds, such as 17% EDTA, may be employed.

Comparative analysis of the effectiveness of mechanical treatment of root canals by various Ni-Ti file systems

INTRODUCTION. One of the main stages of successful endodontic treatment is high-quality mechanical treatment of root canals. А large number of various rotary Ni-Ti files in the dental market poses a difficult choice for the doctor, especially in the context of import substitution. It is necessary to have knowledge about the effectiveness of different system of instruments in a particular clinical case. AIM. With the help of scanning electronic mycoroscopy and computer microtomography, to analyze the quality of mechanical treatment of the root canal with files of domestic and foreign production.MATERIALS AND METHODS. During the study, single-root and multi-root teeth with different root canal curvature were selected, which were distributed according to the Ni-Ti file system used: group 1 – RM files (RusMed), group 2 – ProTaper Universal (Dentsply Mallifier), group 3 – M-two (VDW).RESULTS. The analysis of scanning electron microscopy of tooth showed that the largest number of open dentine tubules is determined when treating the root canal with instruments of the group 1 (55.4±1.37) and group 3 (60.25±1.59). The centering ability with a curvature of the root canal of 20–25° had no significant differences between the tools used. With a curvature of the root canal of 40–45°, the value of this parameter decreased significantly in all groups of instruments, it was greatest in the groups 1 and 3.CONCLUSION. It was revealed that the best quality of mechanical treatment of the root canal was obtained using RM-files and Mtwo in samples with a channel curvature of up to 25°.

Effect of propolis added to single-bottle adhesives on water permeation through the hybrid layer.

Water treeing and water droplets are observed within adhesive layers and on the hybridized surface after bonding sound dentin using single-bottle etch-and-rinse adhesives, indicating permeability of the hybrid layer to water. The aim of this study was to assess the efficacy of dentin sealing by adhesives containing propolis by quantifying the area of water transudation from dentinal tubules after dentin hybridization. Brazilian red propolis was added to experimental adhesive and Single Bond (3M/ESPE) adhesive; experimental adhesive and Single Bond without propolis were used as controls. Under simulated pulp pressure, two layers of adhesive were applied to etched human dentin discs. Three minutes after light-curing, the hybridized dentin surface was replicated, and epoxy resin replicas were created to obtain scanning electron microscope images. Data were evaluated using ANOVA and Tukey's test. Single Bond containing propolis significantly decreased water permeation through the hybrid layer compared with the control group. Three minutes after polymerization, the experimental adhesive without propolis had formed a permeable hybrid layer. The addition of Brazilian red propolis significantly reduced surface water on hybridized dentin in a concentration-dependent manner. Two-step etch-and-rinse adhesives containing propolis were effective in reducing water permeation through the hybridized dentin surface.

Visualization of the dentogingival junction using micro-plastination technique.

Plastination has revolutionized the field of anatomy and research by providing biosecurity and enabling the long-term preservation of biological material, ranging from entire bodies to individual organs and even micron sections. The dentogingival junction (DGJ) consists of both epithelial and connective tissues that are closely related to the tooth's mineralized tissues. Cutting-grinding techniques are commonly used to visualize DGJ histology. These techniques exclude enamel from preparations and focus on visualizing hard or soft tissues. To improve the micro-anatomical and histological study of this region, we applied micro-plastination technique to obtain micro-thin slices below 150 μm thick from human and animal samples. The DGJ microanatomy was visualized by applying histological stains to the micro-plastinated slices, highlighting the technique's endogenous autofluorescence capacity identifying periodontal tissues, including dentin, enamel, cementoenamel junction, dentinal tubules, connective tissue, and collagen. Based on our results, we confirm that micro-plastination is a useful technique for visualizing anatomical regions that are difficult to access, such as the DGJ. Micro-plastination can be used as an alternative technique, providing a new approach for its application in anatomical and morphological research protocols.

A confocal laser scanning microscopic analysis of efficacy of different activated irrigants in the removal of calcium hydroxide medicament and subsequent penetrability of Bio-C sealer – An in vitro study

Abstract Aim: The aim of the study was to investigate the efficacy of different irrigants activated by pro-agitator tip system (PATS) Vario on the removal of calcium hydroxide medicament and subsequent penetration depth of Bio-C sealer. Materials and Methods: Fifty single-rooted mandibular premolars were selected. Access cavities were prepared; biomechanical preparation was done. Metapex that had been combined with rhodamine B dye was used to fill each sample. All the samples were divided into five groups (n = 10) – Group I: chitosan–citrate, Group II: intracanal heated sodium hypochlorite (NaOCl), Group III: phytic acid, Group IV: SmearClear, and Group V: saline. All samples were obturated using gutta-percha and Bio-C sealer (combined with fluorescein dye). Later, all samples were sectioned at 3, 6, and 9 mm from the apex and observed under a confocal microscope for residual Ca(OH)2 and sealer penetration into dentinal tubules. Results: The saline group exhibited the least amount of sealer penetration and high residual Ca(OH)2, both of which were statistically significant (P ≤ 0.05). Conclusion: The use of PATS Vario for irrigant activation enhanced the calcium hydroxide removal efficacy and penetration of Bio-C sealer into dentinal tubules. The elimination of calcium hydroxide and sealer penetration, from the apical region of the tooth, can be accelerated by intracanal heating of NaOCl.

The treatment of Enterococcus faecalis related root canal biofilms with phage therapy

As one of the global concerns, antimicrobial resistance crisis increases the clinical importance of Enterococcus species. Enterococcus faecalis (E. faecalis) specifically penetrates the dentinal tubules and remains prevalent even after endodontic treatment. It has also biofilm forming character as well as the development of resistance to antibiotics. Sodium hypochlorite (NaOCl) is considered the gold standard among antibacterial washing solutions. However, due to its toxic effects, its usage limitations have led to the search for natural, non-toxic alternatives. Phages can be considered an important alternative because of their effects on specific bacteria. The objective of this study was to compare the effect of isolated active vB_Ef1 phage on the removal of E. faecalis biofilm in dentin, together and separately with the chemical irrigation solution NaOCl. As a result of study, the optimal NaOCl solution concentration to be applied with vB_Ef1 phage is 0.5 %, and the use of solution at this value reduces the biofilm mass by 84 %, reaching the highest biofilm mass reduction value. It was found that the combination of phage and NaOCl at appropriate concentrations had the strongest biofilm disruption effect.

Lipoteichoic Acid from Lacticaseibacillus rhamnosus GG as a Novel Intracanal Medicament Targeting Enterococcus faecalis Biofilm Formation.

The demand for safe and effective endodontic medicaments to control Enterococcus faecalis biofilms, a contributor to apical periodontitis, is increasing. Recently, lipoteichoic acid (LTA) of family Lactobacillaceae has been shown to have anti-biofilm effects against various oral pathogens. Preliminary experiments showed that LTA purified from Lacticaseibacillus rhamnosus GG (Lgg.LTA) was the most effective against E. faecalis biofilms among LTAs from three Lactobacillaceae including L. rhamnosus GG, Lacticaseibacillus casei, and Lactobacillus acidophilus. Therefore, in this study, we investigated the potential of Lgg.LTA as an intracanal medicament in human root canals infected with E. faecalis. Twenty eight dentinal cylinders were prepared from extracted human teeth, where two-week-old E. faecalis biofilms were formed followed by intracanal treatment with sterile distilled water (SDW), N-2 methyl pyrrolidone (NMP), calcium hydroxide (CH), or Lgg.LTA. Bacteria and biofilms that formed in the root canals were analyzed by scanning electron microscopy and confocal laser scanning microscopy. The remaining E. faecalis cells in the root canals after intracanal medicament treatment were enumerated by culturing and counting. When applied to intracanal biofilms, Lgg.LTA effectively inhibited E. faecalis biofilm formation as much as CH, while SDW and NMP had little effect. Furthermore, Lgg.LTA reduced both live and dead bacteria within the dentinal tubules, indicating the possibility of minimal re-infection in the root canals. Collectively, intracanal application of Lgg.LTA effectively inhibited E. faecalis biofilm formation, implying that Lgg.LTA can be used as a novel endodontic medicament.

Influence of Dentin Sealing Technique on the Shear Bond Strength between Lithium Disilicate Ceramics and Try-In-Paste-Contaminated Dentin

This study aimed to evaluate the effect of try-in paste contamination on the bond strength of lithium disilicate glass–ceramic to dentin treated with immediate (IDS) or delayed (DDS) dentin sealing techniques. Occlusal halves of 33 molars were decapitated and divided into three groups (n = 10). Lithium disilicate discs (3 × 5 mm) were prepared. For Group A, the provisional crown was applied over dentin and was soaked in distilled water. Lithium disilicate discs were cemented following dentin conditioning with a three-step etch and rinse adhesive. In Group B (IDS), the three-step adhesive was applied to dentin. The dentin surfaces were conditioned only in the final cementation for Group C (DDS). The intaglio surfaces of test groups were contaminated with try-in paste. All specimens were thermally cycled 3000 times at 5–55 °C and were subjected to shear tests. An additional three specimens for each group were contaminated with try-in paste and subjected to the same surface cleaning as the test specimens were examined with SEM/EDS. The adhesive surfaces were also examined with SEM/EDS for try-in paste remnants. Group C showed a significant decrease in bond strength values compared to Group B and Group A (5.84 ±1.4 MPa, 11.45 ±2.4 MPa, and 10.29 ±2.5 MPa, respectively). No statistically significant difference was detected between Group B and Group A (p ≥ 0.05). The SEM-EDS analyses revealed obstructions of the dentinal tubules in the try-in-paste-contaminated specimens. Immediate dentin sealing application enhanced the bonding strength of lithium disilicate to the try-in-paste-contaminated dentin. Try-in paste contamination over dentin negatively influenced the bonding process.