Evaluation of the root dentin bond strength and intratubular biomineralization of a premixed calcium aluminate-based hydraulic bioceramic endodontic sealer.

PURPOSE: This study evaluated the dentin bonding strength and biomineralization effect of a recently developed premixed calcium aluminate-based endodontic sealer (Dia-Root Bio Sealer) in comparison with existing calcium silicate-based sealers. METHODS: The root canals of 80 mandibular premolars were filled with Dia-Root Bio Sealer, Endoseal MTA, EndoSequence BC Sealer, and AH Plus Bioceramic Sealer. Medial and apical specimens were then obtained by sectioning. The push-out bond strength was measured using the medial specimens, and the failure mode was recorded. Intratubular biomineralization in the apical specimens was analyzed using scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDS). The data were analyzed using one-way analysis of variance followed by the Tukey test (P < 0.05). RESULTS: The push-out bond strength of Dia-Root Bio Sealer was significantly higher than that of the other tested materials, and a cohesive failure pattern was observed in all groups. Dia-Root Bio Sealer also exhibited a significantly higher degree of biomineralization than the other groups, and EDS analysis indicated that the biomineralized precipitates were amorphous calcium phosphate. CONCLUSION: The results of this study indicate that Dia-Root Bio Sealer has the potential to be used as an adequate root canal sealer due to its favorable bonding performance.

Surface property changes observed in zirconia during etching with high-concentration hydrofluoric acid over various immersion times.

This study investigated the degree of phase transformation, surface roughness, and bond strength of zirconia immersed for various times in a 40% hydrofluoric acid (HF) solution. Non-etched sintered zirconia specimens were used as the control, while experimental groups were etched with a 40% HF solution for 5, 10, 20, 40, 80, 160 and 320 min. In each of the control and experimental groups, five specimens for X-ray diffraction analysis, four for surface morphology and surface roughness analysis, and ten for bonding strength measurement were used. As a result, the surface roughness of zirconia increased as the application time increased during the 40% HF etching, but the bond strength between zirconia and resin cement did not increase proportionally. The phase transformation from tetragonal to monoclinic also gradually increased with application time.

Evaluation of machine-assisted irrigation on removal of intracanal biofilm and extrusion of sodium hypochlorite using a three-dimensionally printed root canal model.

PURPOSE: This study aimed to compare the biofilm removal and apical extrusion of sodium hypochlorite (NaOCl) following machine-assisted irrigation using a three-dimensionally (3D) printed dentin-insert model. METHODS: Multispecies biofilms were formed in a 3D-printed curved root canal model with dentin insert. The model was then placed in a container that was filled with 0.2% agarose gel containing 0.1% m-Cresol purple. Root canals were irrigated with 1% NaOCl using syringe irrigation, sonically agitated (EndoActivator or EDDY) or ultrasonically activated (Endosonic Blue) irrigation. Samples were photographed and the color-changed area was measured. Biofilm removal was assessed using colony-forming unit counting, confocal laser scanning microscopic analysis and scanning electron microscopic observations. The data were analyzed using one-way ANOVA, followed by Tukey test (P < 0.05). RESULTS: EDDY and Endosonic Blue demonstrated significantly greater reduction of biofilms compared to other groups. No significant differences were observed in the remaining biofilm volume in syringe irrigation and EndoActivator groups. Furthermore, EDDY and Endosonic Blue presented with numerous exposed dentinal tubules. EDDY showed significantly greater NaOCl extrusion compared to other groups. CONCLUSION: Ultrasonic activation with a small-sized nickel-titanium file irrigation system may be beneficial in intracanal biofilm removal avoiding extrusion of NaOCl beyond the root apex.

Push-out bond strength and intratubular biomineralization of a hydraulic root-end filling material premixed with dimethyl sulfoxide as a vehicle.

Objectives: This study was designed to evaluate the parameters of bonding performance to root dentin, including push-out bond strength and dentinal tubular biomineralization, of a hydraulic bioceramic root-end filling material premixed with dimethyl sulfoxide (Endocem MTA Premixed) in comparison to a conventional powder-liquid-type cement (ProRoot MTA). Materials and Methods: The root canal of a single-rooted premolar was filled with either ProRoot MTA or Endocem MTA Premixed (n = 15). A slice of dentin was obtained from each root. Using the sliced specimen, the push-out bond strength was measured, and the failure pattern was observed under a stereomicroscope. The apical segment was divided into halves; the split surface was observed under a scanning electron microscope, and intratubular biomineralization was examined by observing the precipitates formed in the dentinal tubule. Then, the chemical characteristics of the precipitates were evaluated with energy-dispersive X-ray spectroscopic (EDS) analysis. The data were analyzed using the Student's t-test followed by the Mann-Whitney U test (p < 0.05). Results: No significant difference was found between the 2 tested groups in push-out bond strength, and cohesive failure was the predominant failure type. In both groups, flake-shaped precipitates were observed along dentinal tubules. The EDS analysis indicated that the mass percentage of calcium and phosphorus in the precipitate was similar to that found in hydroxyapatite. Conclusions: Regarding bonding to root dentin, Endocem MTA Premixed may have potential for use as an acceptable root-end filling material.

Effects of barium titanate on the dielectric constant, radiopacity, and biological properties of tricalcium silicate-based bioceramics.

This study evaluated the effect of barium titanate (BT) on the dielectricity, radiopacity, and biological properties of tricalcium silicate (C3S). C3S/BT samples were prepared with varying proportions of BT (0, 20, 40, and 60 wt%; referred to as BT00, BT20, BT40, and BT60, respectively). Dielectric constant and radiopacity were measured. Cytocompatibility was evaluated on human dental pulp cells. After surgical procedures on rat mandible, immunohistochemistry and Masson's trichrome staining were performed. The dielectric constant increased with higher proportions of BT (p<0.05). BT40 and BT60 satisfied the clinical guideline of radiopacity. There were no significant differences among groups in the cytocompatibility tests (p>0.05). New bone was observed well, along with the expressions of the dentin matrix protein 1 (DMP1), osteocalcin (OC), and osteonectin (ON) in BT40 and BT60. Conclusively, the contents of 40-60 wt% of BT in C3S provided proper radiopacity, favorable cytocompatibility, and beneficial effect on bone regeneration.

Change of phase transformation and bond strength of Y-TZP with various hydrofluoric acid etching.

OBJECTIVES: The purpose of this study was to quantify phase transformation after hydrofluoric acid (HF) etching at various concentrations on the surface of yttria-stabilized tetragonal zirconia polycrystal (Y-TZP), and to evaluate changes in bonding strength before and after thermal cycling. MATERIALS AND METHODS: A group whose Y-TZP surface was treated with tribochemical silica abrasion (TS) was used as the control. Y-TZP specimens from each experimental group were etched with 5%, 10%, 20%, and 40% HF solutions at room temperature for 10 minutes. First, to quantify the phase transformation, Y-TZP specimens (n = 5) treated with TS, 5%, 10%, 20% and 40% HF solutions were subjected to X-ray diffraction. Second, to evaluate the change in bond strength before and after thermal cycling, zirconia primer and MDP-containing resin cement were sequentially applied to the Y-TZP specimen. After 5,000 thermal cycles for half of the Y-TZP specimens, shear bond strength was measured for all experimental groups (n = 10). RESULTS: The monoclinic phase content in the 40% HF-treated group was higher than that of the 5%, 10%, and 20% HF-treated groups, but lower than that of TS-treated group (p < 0.05). The 40% HF-treated group showed significantly higher bonding strength than the TS, 5%, and 10% HF-treated groups, even after thermal cycling (p < 0.05). CONCLUSIONS: Through this experiment, the group treated with SiO2 containing air-borne abrasion on the Y-TZP surface showed higher phase transformation and higher reduction in bonding strength after thermal cycling compared to the group treated with high concentration HF.

A novel three-dimensionally printed model to assess biofilm removal by ultrasonically activated irrigation.

AIM: To apply an innovative three-dimensionally printed tooth model to investigate the efficacy of three ultrasonically activated irrigation (UAI) systems in removing multispecies biofilms from dentine samples. METHODOLOGY: Three-dimensionally printed teeth with a curved root canal were fabricated with a standardized slot in the apical third of the root to achieve precision fit of human root dentine specimens. Multispecies biofilms including Enterococcus faecalis, Streptococcus mitis and Campylobacter rectus were developed in the root canal for 21 days. The canals were allocated to be irrigated with 1% sodium hypochlorite (NaOCl) using a syringe and needle or ultrasonically activated NaOCl with a stainless-steel file (Irrisafe), a conventional nickel-titanium (Ni-Ti) file (CK) or a blue heat-treated Ni-Ti file (Endosonic Blue). Infected root canals irrigated with distilled water served as controls. Bacterial reduction was determined by colony-forming unit (CFU) counting (n = 20), whilst biofilms were analysed using confocal laser scanning microscopy (n = 7) and field emission scanning electron microscopy. For CFU counting, the independent two-sample t-test (Welch's t-test) was examined to compare overall bacterial reduction amongst groups. For CLSM analysis, the data were analysed using one-way analysis of variance (ANOVA), followed by the Scheffé post hoc test. The p-values <.05 were considered to indicate statistical significance. RESULTS: All groups in which NaOCl was ultrasonically activated had significantly lower CFU values than the syringe-and-needle irrigation and control groups (p < .05). Ultrasonic activation with the stainless-steel file and blue heat-treated Ni-Ti file significantly reduced the biofilm volume compared with other groups (p < .05). Overall, UAI with the blue heat-treated file resulted in the highest antibacterial and biofilm removal efficacy. CONCLUSIONS: UAI with different inserts had differential antibiofilm effects. The blue heat-treated Ni-Ti ultrasonic insert resulted in the greatest antibacterial and biofilm removal from dentine in this standardized root canal model.

Changes in Bond Strength and Topography for Y-TZP Etched with Hydrofluoric Acid Depending on Concentration and Temperature Conditions.

Background and objectives: This study aimed to investigate the change in bond strength between resin cement and tetragonal zirconia polycrystalline stabilized with 3 to 8 mol% yttrium oxide (Y-TZP) and observe the topographical change of the Y-TZP surface when etched with hydrofluoric acid (HF) solution under different concentration and temperature conditions. Materials and Methods: Non-etched sintered Y-TZP specimens under two different temperature conditions (room temperature and 70-80 °C, respectively), were used as a control, while experimental groups were etched with 5%, 10%, 20%, and 40% HF solutions for 10 min. After zirconia primer and MDP-containing resin cement were applied to the Y-TZP surface, the shear bond strength (SBS) of each experimental group was measured. Results: Under room temperature conditions, the highest SBS value was measured in the 40% HF etching group, representing a significant deviation from the other groups (p < 0.05). In the 70-80 °C tests, the 40% HF etching group also had the highest SBS value, but there was no significant difference when compared to the 20% HF etching group (p > 0.05). From SEM and AFM observations, the HF solution increasingly dissolved the Y-TZP surface grain structure as the concentration and application temperature rose, resulting in high surface roughness and irregularities. Conclusions: Pretreating with either 20% HF solution at 70-80 °C or 40% HF solution at room temperature and 70-80 °C effectively acid etched the Y-TZP surface, resulting in more surface roughness and irregularities. Accounting for the concentration and temperature conditions of the HF solution, using 40% HF solution at room temperature will result in improvements in adhesion between resin cement and Y-TZP.

Main and Accessory Canal Filling Quality of a Premixed Calcium Silicate Endodontic Sealer According to Different Obturation Techniques.

The present study aimed to investigate the effects of different obturation techniques on the main and accessory canal filling quality of a premixed calcium silicate endodontic sealer (Endoseal TCS). We also highlighted the validity of the methods used for evaluating the canal filling quality. Thirty single-rooted premolars were used for the main canal filling and 75 were used for accessory canal filling. The canals were instrumented and randomly divided into three groups according to the filling techniques: (1) single-cone technique (SC), (2) single-cone with ultrasonic activation (SU), and (3) warm vertical compaction (WV). Voids in relation to the root canal fillings were assessed using cross-section images from microcomputed tomography (µCT) scans or transversely sectioned tooth specimens (n = 10). After demineralization and clearing of the teeth, the incidence, number, and completeness of the accessory canal fillings were evaluated (n = 25). One-way analysis of variance (ANOVA) and Tukey's post hoc test was used for the evaluation of the voids in the main root canal and the incidence and number of filled accessory canals. Pearson's chi-squared (χ2) test was used for the evaluation of the filling completeness (α = 0.05). In the stereomicroscopic evaluation of the sectioned specimen, the SC group had significantly higher void occurrence than the other groups (p < 0.05), although there was no difference between groups in the µCT evaluation. However, there was no difference between the SU and WV. There was no difference between all the groups regarding the incidence, number, and completeness of the accessory canal fillings. When the premixed calcium silicate sealer is used with SC, the ultrasonic activation is recommended to obtain a better main canal filling quality. In contrast, the obturation techniques did not affect the accessory canal filling. We also recommend using the sectioning method when the void formation in the root canal filling materials is evaluated.

Effect of hydrofluoric acid-based etchant at an elevated temperature on the bond strength and surface topography of Y-TZP ceramics.

OBJECTIVES: This study investigated the effects of a hydrofluoric acid (HA; solution of hydrogen fluoride [HF] in water)-based smart etching (SE) solution at an elevated temperature on yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) ceramics in terms of bond strength and morphological changes. MATERIALS AND METHODS: Eighty sintered Y-TZP specimens were prepared for shear bond strength (SBS) testing. The bonding surface of the Y-TZP specimens was treated with 37% phosphoric acid etching at 20°C-25°C, 4% HA etching at 20°C-25°C, or HA-based SE at 70°C-80°C. In all groups, zirconia primers were applied to the bonding surface of Y-TZP. For each group, 2 types of resin cement (with or without methacryloyloxydecyl dihydrogen phosphate [MDP]) were used. SBS testing was performed. Topographic changes of the etched Y-TZP surface were analyzed using scanning electron microscopy and atomic force microscopy. The results were analyzed and compared using 2-way analysis of variance. RESULTS: Regardless of the type of resin cement, the highest bond strength was measured in the SE group, with significant differences compared to the other groups (p < 0.05). In all groups, MDP-containing resin cement yielded significantly higher bond strength values than MDP-free resin cement (p < 0.05). It was also shown that the Y-TZP surface was etched by the SE solution, causing a large change in the surface topography. CONCLUSIONS: Bond strength significantly improved when a heated HA-based SE solution was applied to the Y-TZP surface, and the etched Y-TZP surface was more irregular and had higher surface roughness.

Effects of different silica-based layer coatings on bond strength of Y-TZP to bovine dentin.

This study investigated the effects of different silica-based layer coatings on shear bond strength (SBS) between Y-TZP and bovine dentin. Three different silica-based layer coatings were applied to the Y-TZP surface: tribochemical silica coating, vitrification (glaze coating), and composite resin sintering. A silane coupling agent (SIL) was applied to the silica-coated Y-TZP surface in the presence or absence of hydrofluoric acid (HF) treatment. A one-step adhesive was then applied to the silica-coated Y-TZP and cemented to bovine dentin using MDP-free resin cement. The SBS value of the tribochemical silica coating group was lowest among the experimental groups, while the HF+SIL subgroup showed the highest SBS value after vitrification (p<0.05). While hydrofluoric acid etching did not affect the SBS value of the tribochemical silica coating group, it affected the SBS value in the vitrification and composite resin sintering groups (p<0.05).

Surgical management of an accessory canal in a maxillary premolar: a case report.

We report the surgical endodontic treatment of a maxillary first premolar with a lateral lesion that originated from an accessory canal. Although lesions originating from accessory canals frequently heal with simple conventional endodontic therapy, some lesions may need additional and different treatment. In the present case, conventional root canal retreatment led to incomplete healing with the need for further treatment (i.e., surgery). Surgical endodontic management with a fast-setting calcium silicate cement was performed on the accessory canal using a dental operating microscope. At the patient's 9-month recall visit, the lesion was resolved upon radiography.

Role of extracellular DNA in Enterococcus faecalis biofilm formation and its susceptibility to sodium hypochlorite.

OBJECTIVE: This study investigated the role of extracellular deoxyribonucleic acid (eDNA) on Enterococcus faecalis ( E. faecalis ) biofilm and the susceptibility of E. faecalis to sodium hypochlorite (NaOCl). METHODOLOGY: E. faecalis biofilm was formed in bovine tooth specimens and the biofilm was cultured with or without deoxyribonuclease (DNase), an inhibitor of eDNA. Then, the role of eDNA in E. faecalis growth and biofilm formation was investigated using colony forming unit (CFUs) counting, eDNA level assay, crystal violet staining, confocal laser scanning microscopy, and scanning electron microscopy. The susceptibility of E. faecalis biofilm to low (0.5%) or high (5%) NaOCl concentrations was also analyzed by CFU counting. RESULTS: CFUs and biofilm formation decreased significantly with DNase treatment (p<0.05). The microstructure of DNase-treated biofilms exhibited less structured features when compared to the control. The volume of exopolysaccharides in the DNase-treated biofilm was significantly lower than that of control (p<0.05). Moreover, the CFUs, eDNA level, biofilm formation, and exopolysaccharides volume were lower when the biofilm was treated with DNase de novo when compared to when DNase was applied to matured biofilm (p<0.05). E. faecalis in the biofilm was more susceptible to NaOCl when it was cultured with DNase (p<0.05). Furthermore, 0.5% NaOCl combined with DNase treatment was as efficient as 5% NaOCl alone regarding susceptibility (p>0.05). CONCLUSIONS: Inhibition of eDNA leads to decrease of E. faecalis biofilm formation and increase of susceptibility of E. faecalis to NaOCl even at low concentrations. Therefore, our results suggest that inhibition of eDNA would be beneficial in facilitating the efficacy of NaOCl and reducing its concentration.

Effects of dodecacalcium hepta-aluminate content on the setting time, compressive strength, alkalinity, and cytocompatibility of tricalcium silicate cement.

OBJECTIVE: This study aimed to investigate the effects of dodecacalcium hepta-aluminate (C12A7) content on some physicochemical properties and cytocompatibility of tricalcium silicate (C3S) cement using human dental pulp cells (hDPCs). MATERIAL AND METHODS: High purity C3S cement was manufactured by a solid phase method. C12A7 was mixed with the cement in proportions of 0, 5, 8, and 10 wt% (C12A7-0, -5, -8, and -10, respectively). Physicochemical properties including initial setting time, compressive strength, and alkalinity were evaluated. Cytocompatibility was assessed with cell viability tests and cell number counts. Statistical analysis was performed by using one-way analysis of variance (ANOVA) and Tukey's test (p<0.05). RESULTS: The initial setting time of C3S-based cement was shorter in the presence of C12A7 (p<0.05). After 1 day, C12A7-5 showed significantly higher compressive strength than the other groups (p<0.05). After 7 days, the compressive strength of C12A7-5 was similar to that of C12A7-0, whereas other groups showed strength lower than C12A7-0. The pH values of all tested groups showed no significant differences after 1 day (p>0.05). The C12A7-5 group showed similar cell viability to the C12A7-0 group (p>0.05), while the other experimental groups showed lower values compared to C12A7-0 group (p<0.05). The number of cells grown on the C12A7-5 specimen was higher than that on C12A7-8 and -10 (p<0.05). CONCLUSIONS: The addition of C12A7 to C3S cement at a proportion of 5% resulted in rapid initial setting time and higher compressive strength with no adverse effects on cytocompatibility.

Role of extracellular DNA in Enterococcus faecalis biofilm formation and its susceptibility to sodium hypochlorite

Abstract Objective This study investigated the role of extracellular deoxyribonucleic acid (eDNA) on Enterococcus faecalis ( E. faecalis ) biofilm and the susceptibility of E. faecalis to sodium hypochlorite (NaOCl). Methodology E. faecalis biofilm was formed in bovine tooth specimens and the biofilm was cultured with or without deoxyribonuclease (DNase), an inhibitor of eDNA. Then, the role of eDNA in E. faecalis growth and biofilm formation was investigated using colony forming unit (CFUs) counting, eDNA level assay, crystal violet staining, confocal laser scanning microscopy, and scanning electron microscopy. The susceptibility of E. faecalis biofilm to low (0.5%) or high (5%) NaOCl concentrations was also analyzed by CFU counting. Results CFUs and biofilm formation decreased significantly with DNase treatment (p<0.05). The microstructure of DNase-treated biofilms exhibited less structured features when compared to the control. The volume of exopolysaccharides in the DNase-treated biofilm was significantly lower than that of control (p<0.05). Moreover, the CFUs, eDNA level, biofilm formation, and exopolysaccharides volume were lower when the biofilm was treated with DNase de novo when compared to when DNase was applied to matured biofilm (p<0.05). E. faecalis in the biofilm was more susceptible to NaOCl when it was cultured with DNase (p<0.05). Furthermore, 0.5% NaOCl combined with DNase treatment was as efficient as 5% NaOCl alone regarding susceptibility (p>0.05). Conclusions Inhibition of eDNA leads to decrease of E. faecalis biofilm formation and increase of susceptibility of E. faecalis to NaOCl even at low concentrations. Therefore, our results suggest that inhibition of eDNA would be beneficial in facilitating the efficacy of NaOCl and reducing its concentration.

Effects of dodecacalcium hepta-aluminate content on the setting time, compressive strength, alkalinity, and cytocompatibility of tricalcium silicate cement

Abstract Objective This study aimed to investigate the effects of dodecacalcium hepta-aluminate (C12A7) content on some physicochemical properties and cytocompatibility of tricalcium silicate (C3S) cement using human dental pulp cells (hDPCs). Material and Methods High purity C3S cement was manufactured by a solid phase method. C12A7 was mixed with the cement in proportions of 0, 5, 8, and 10 wt% (C12A7-0, −5, −8, and −10, respectively). Physicochemical properties including initial setting time, compressive strength, and alkalinity were evaluated. Cytocompatibility was assessed with cell viability tests and cell number counts. Statistical analysis was performed by using one-way analysis of variance (ANOVA) and Tukey's test (p<0.05). Results The initial setting time of C3S-based cement was shorter in the presence of C12A7 (p<0.05). After 1 day, C12A7-5 showed significantly higher compressive strength than the other groups (p<0.05). After 7 days, the compressive strength of C12A7-5 was similar to that of C12A7-0, whereas other groups showed strength lower than C12A7-0. The pH values of all tested groups showed no significant differences after 1 day (p>0.05). The C12A7-5 group showed similar cell viability to the C12A7-0 group (p>0.05), while the other experimental groups showed lower values compared to C12A7-0 group (p<0.05). The number of cells grown on the C12A7-5 specimen was higher than that on C12A7-8 and −10 (p<0.05). Conclusions The addition of C12A7 to C3S cement at a proportion of 5% resulted in rapid initial setting time and higher compressive strength with no adverse effects on cytocompatibility.

The effect of continuous application of MDP-containing primer and luting resin cement on bond strength to tribochemical silica-coated Y-TZP.

OBJECTIVES: This study investigated the effect of continuous application of 10-methacryloyloxydecyldihydrogen phosphate (MDP)-containing primer and luting resin cement on bond strength to tribochemical silica-coated yttria-stabilized tetragonal zirconia polycrystal (Y-TZP). MATERIALS AND METHODS: Forty bovine teeth and Y-TZP specimens were prepared. The dentin specimens were embedded in molds, with one side of the dentin exposed for cementation with the zirconia specimen. The Y-TZP specimen was prepared in the form of a cylinder with a diameter of 3 mm and a height of 10 mm. The bonding surface of the Y-TZP specimen was sandblasted with silica-coated aluminium oxide particles. The forty tribochemical silica-coated Y-TZP specimens were cemented to the bovine dentin (4 groups; n = 10) with either an MDP-free primer or an MDP-containing primer and either an MDP-free resin cement or an MDP-containing resin cement. After a shear bond strength (SBS) test, the data were analyzed using 1-way analysis of variance and the Tukey test (α = 0.05). RESULTS: The group with MDP-free primer and resin cement showed significantly lower SBS values than the MDP-containing groups (p < 0.05). Among the MDP-containing groups, the group with MDP-containing primer and resin cement showed significantly higher SBS values than the other groups (p < 0.05). CONCLUSIONS: The combination of MDP-containing primer and luting cement following tribochemical silica coating to Y-TZP was the best choice among the alternatives tested in this study.

Root Canal Filling Quality of a Premixed Calcium Silicate Endodontic Sealer Applied Using Gutta-percha Cone-mediated Ultrasonic Activation.

INTRODUCTION: The aim of this study was to investigate the filling quality of a recently developed premixed calcium silicate-based endodontic sealer (Endoseal MTA) with a single gutta-percha (GP) cone technique compared with a resin-based sealer (AH plus) with warm vertical compaction. We also explored the effect of GP cone-mediated ultrasonic activation on the filling quality of Endoseal MTA. METHODS: Thirty human single-rooted maxillary premolars with ribbon-shaped canals were prepared and assigned to 3 experimental groups according to filling method: EMS group was Endoseal MTA + single-cone; EMSU group was Endoseal MTA + single-cone with ultrasonic activation; and the APW group was AH plus + warm vertical compaction. Each tooth was scanned using micro-computed tomography (µ-CT), and the proportions of sections with void and the volume percentages of void were calculated. Then, the tooth was sectioned transversely, and the presence of void in the slices was scored under a stereomicroscope. The data were statistically analyzed using 1-way analysis of variance and Tukey tests to detect any significance (α = 0.05). RESULTS: In the µ-CT assessment, there was no significant difference among the groups regarding the proportion of sections with void and the void volume percentage (P > .05). However, in the stereomicroscopic evaluation, the EMS group showed a higher number of voids and a higher void score compared with the other groups (P < .05). CONCLUSION: Endoseal MTA performs best when used with GP cone-mediated ultrasonic activation. Furthermore, stereomicroscopic observation of sections of the specimens should be performed when evaluating root canal filling quality.

Removal efficacy and cytotoxicity of a calcium hydroxide paste using N-2-methyl-pyrrolidone as a vehicle.

OBJECTIVES: This study investigated the removal efficacy and cytotoxicity of a newly developed calcium hydroxide paste (cleaniCal, Maruchi) using N-2-methyl-pyrrolidone (NMP) as a vehicle in comparison with ApexCal (Ivoclar Vivadent) and Calcipex II (Nishika), which use different vehicles such as polyethylene glycol and propylene glycol, respectively. MATERIALS AND METHODS: Thirty maxillary premolars with oval-shaped canals were divided into 3 groups and the teeth were filled with one of the pastes. After removal of the paste, micro-computed tomographic (µ-CT) imaging was obtained to assess the volume of residual paste in the root canal of each tooth. The teeth were then split longitudinally and the area of the paste-coated surface was evaluated by stereomicroscopy. The cytotoxicity of each product was assessed using an agar overlay assay. The effect of each vehicle on cell viability was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The data were analyzed using one-way analysis of variance and Tukey's tests to detect any significance (p < 0.05). RESULTS: In the µ-CT and stereomicroscopic analysis, cleaniCal exhibited less remnants of medicament than ApexCal and Calcipex. cleaniCal showed a higher cytotoxicity than the other pastes in the agar overlay assay. Furthermore, NMP exhibited lower cell viability compared to the other vehicles. CONCLUSIONS: cleaniCal showed better removal efficacy compared to the other products. However, clinicians should be aware of the higher cytotoxicity of the NMP-based material and consider its possible adverse effects on periradicular tissue when it is overfilled.

Recognition and management of palatogingival groove for tooth survival: a literature review.

Palatogingival groove (PGG) is an anomaly in the maxillary anterior teeth, often accompanied by the area of bony destruction adjacent to the teeth with no carious or traumatic history. The hidden trap in the tooth can harbor plaque and bacteria, resulting in periodontal destruction with or without pulpal pathologic change. Related diseases can involve periodontal destruction, combined endodontic-periodontal lesions, or separate endodontic and periodontal lesions. Disease severity and prognosis related to PGG depend on several factors, including location, range, depth, and type of the groove. Several materials have been used and recommended for cases of extensive periodontal destruction from PGG to remove and block the inflammatory source and recover the health of surrounding periodontal tissues. Even in cases of severe periodontal destruction, several studies have reported favorable treatment outcomes with proper management. With new options in diagnosis and treatment, clinicians need a detailed understanding of the characteristics, treatment, and prognosis of PGG to successfully manage the condition.