Influence of acidic pH on antimicrobial activity of different calcium silicate based-endodontic sealers.

OBJECTIVE: To investigate the antibacterial activity of calcium silicate-based sealers (CSBSs) against Enterococcus faecalis biofilm in a neutral or acidic condition. MATERIALS AND METHODS: Dentin cylinders (4 mm length) were prepared and infected with 3-week-old E. faecalis. The samples were filled with BioRoot RCS (BR), EndoSequence BC (ES), and NeoMTA Plus (NMTA) and incubated in either neutral or acidic conditions for 7 days (n=10/group). Sterile or infected samples alone were used as the positive and negative control. The root canal sealers were removed after 7 days, and the remaining bacteria on dentinal walls were determined by colony-forming units (CFUs/ml), and three samples from each group were visualized under a confocal laser scanning microscope (CLSM). The pH was also measured (n=3/group) after 4 h and 7 days of incubation at 37°C in both conditions. RESULTS: In the neutral condition, all sealers significantly decreased the log-CFU values (p<0.05), while in the acidic condition, the log-CFU reduction was less for ES and NMTA, but a higher reduction was observed in BR (p<0.05). The antibacterial activity of CSBSs was similar in neutral conditions (p>0.05), and BR showed a greater antibacterial effect than ES and NMTA in the acidic condition (p<0.05). The pH of BR, ES, and NMTA ranged from 8.2 to 8.8 in the neutral condition in the presence of dentin after 7 days. However, acidic conditions reduced the pH values to 7.8 for BR, 6.0 for ES, and 5.8 for NMTA. CONCLUSIONS: All CSBSs showed similar antibacterial activity in neutral conditions, while acidic pH had a reducing antibacterial effect on CSBSs. CLINICAL RELEVANCE: Inflammatory pH decreased the antibacterial properties of CSBSs depending on the sealer type.

Effect of irrigants on the color stability, solubility, and surface characteristics of calcium-silicate based cements.

Objectives: This study aimed to investigate the color stability, solubility, and surface characteristics of 3 calcium silicate-based cements (CSCs) after immersion in different solutions. Materials and Methods: ProRoot white mineral trioxide aggregate (MTA), Biodentine, and Endosequence Root Repair Material (ERRM) were placed in cylindrical molds and stored at 37°C for 24 hours. Each specimen was immersed in distilled water, 5% sodium hypochlorite (NaOCl), 2% chlorhexidine, or 0.1% octenidine hydrochloride (OCT) for 24 hours. Color changes were measured with a spectrophotometer. Solubility was determined using an analytical balance with 10-5 g accuracy. The surface characteristics were analyzed using scanning electron microscopy and energy-dispersive spectroscopy. Data were analyzed using 2-way analysis of variance, the Tukey test, and the paired t-test. Results: MTA exhibited significant discoloration in contact with NaOCl (p < 0.05). White precipitation occurred on the surfaces of Biodentine and ERRM after contact with the solutions, and none of the materials presented dark brown discoloration. All materials showed significant solubility after immersion in the solutions (p < 0.05), irrespective of the solution type (p > 0.05). The surface topography and elemental composition of the samples showed different patterns of crystal formation and precipitation depending on the solution type. Conclusions: All materials presented some amount of solubility and showed crystal precipitation after contact with the solutions. Biodentine and ERRM are suitable alternatives to ProRoot MTA as they do not exhibit discoloration. The use of OCT can be considered safe for CSCs.

The additive effect of iloprost on the biological properties of Mineral trioxide aggregate on mesenchymal stem cells.

BACKGROUND/PURPOSE: Iloprost has been proposed as a potential biomaterial owing to angiogenic and odontogenic properties. However, the liquid form can limit its use during clinical applications. Mineral trioxide aggregate (MTA) has been used for various dental applications in which cell-material interaction is essential. This study aimed to investigate additive effects of iloprost on the biological properties of MTA on the viability, attachment, migration and differentiation of human mesenchymal stem cells (hMSCs). MATERIALS AND METHODS: Standardized human dentin disks were prepared. MTA was prepared by mixing distilled water or iloprost solution, and the lumen of the disks was filled with MTA or MTA-iloprost. hMSCs on disk alone and hMSCs on culture plates were used as controls. Cell viability and attachment were measured after 1, 7 and 14 days using AlamarBlue assay and scanning electron microscopy (SEM). Cell migration in MTA or MTA-iloprost extracts was determined using a wound-healing model.Osteogenic differentiation was evaluated by real-time reverse transcriptase polymerase chain reaction for alkaline phosphatase (ALP), bone sialoprotein (BSP), osteocalcin (OCN), and osteopontin (OSP) gene expressions after 7 and 14 days of osteogenic induction. RESULTS: Cells on MTA-iloprost surface showed similar viability with MTA at 1 and 14 days but enhanced cellular viability and cell spreading compared to MTA at 7 days (p < 0.05). Cell migration was similar by MTA-iloprost and MTA extracts (p > 0.05). MTAiloprost significantly upregulated BSP, OCN and OSP expressions compared to MTA (p < 0.05). CONCLUSION: The addition of iloprost to MTA improved the initial cell viability and osteogenic potential of hMSCs.

A new direction in managing avulsed teeth: stem cell-based de novo PDL regeneration.

Management of avulsed teeth after replantation often leads to an unfavorable outcome. Damage to the thin and vulnerable periodontal ligament is the key reason for failure. Cell- or stem cell-based regenerative medicine has emerged in the past two decades as a promising clinical treatment modality to improve treatment outcomes. This concept has also been tested for the management of avulsed teeth in animal models. This review focuses on the discussion of limitation of current management protocols for avulsed teeth, cell-based therapy for periodontal ligament (PDL) regeneration in small and large animals, the challenges of de novo regeneration of PDL on denuded root in the edentulous region using a mini-swine model, and establishing a prospective new clinical protocol to manage avulsed teeth based on the current progress of cell-based PDL regeneration studies.

Cell-derived Extracellular Matrix Proteins in Colloidal Microgel as a Self-Assembly Hydrogel for Regenerative Endodontics.

INTRODUCTION: This study investigated a colloidal microgel for angiogenic and odontogenic differentiation of cells in the presence of cell-derived extracellular matrix (ECM) proteins using a 3-dimensional culture model. METHODS: Viscoelastic properties of human dental pulp were determined to understand the native ECM environment. ECM proteins were extracted from dental pulp stem cell (DPSC) cultures, and MaxGel (Millipore Sigma, Burlington, MA) was used as a commercially available ECM protein. DPSCs were incubated in colloidal microgels in the presence of ECM proteins or gelatin methacryloyl (GelMA) as a bulk hydrogel (n = 9/group). The viability and odontogenic differentiation of DPSCs within hydrogels was determined using viability assays, mineralization staining, calcium and alkaline phosphatase assays, and quantitative polymerase chain reaction for odontogenic gene expression. Angiogenic properties of endothelial cells were determined using tubule formation assays and quantitative polymerase chain reaction to detect angiogenic gene expression. RESULTS: Dental pulp had a higher elastic modulus than the viscous modulus, showing a solidlike response similar to hydrogels. DPSC-derived ECM showed higher collagen and GAG than MaxGel (P < .05). The viability of DPSCs was similar in colloidal microgels, whereas higher cell viability, calcium deposition, and alkaline phosphatase activity were observed in GelMA (P < .05). Colloidal microgels allowed tubule-like structures by endothelial cells, whereas no tubular formation was observed in GelMA. DPSC-derived ECM in colloidal microgel up-regulated odontogenic gene expression, whereas MaxGel up-regulated angiogenic gene expression (P < .05). CONCLUSIONS: Colloidal microgels allowed cellular organization that can improve penetration and nutritional supply in a full-length root canal system. The bioactivity of cell-derived ECM proteins can be modified depending on the external stimulus.

Antibacterial Effect and Bioactivity of Innovative and Currently Used Intracanal Medicaments in Regenerative Endodontics.

INTRODUCTION: The purpose of this study was to determine the antibacterial effect and bioactivity of triple antibiotic paste (TAP), calcium hydroxide (Ca[OH]2), and calcium hypochlorite (Ca[OCl]2). METHODS: Root canals were infected with 3-week-old Enterococcus faecalis biofilm and then medicated for 7 days with TAP, Ca(OH)2, or Ca(OCl)2 (n = 10/group). Untreated and uninfected canals were used as positive and negative controls. The antibacterial effect was determined using colony-forming units and a Live/Dead bacterial viability kit. Dental pulp stem cells were seeded on medicated dentin surfaces for 7 days. Sodium thiosulfate and various concentrations of ascorbic acid (1%, 5%, and 10%) were also used to neutralize the samples treated with Ca(OCl)2 before cell seeding (n = 3 in triplicate). Cell viability and morphology were evaluated using a viability assay and Live/Dead cell analysis. Alkaline phosphatase (ALP) activity was also measured to determine the cells' mineralization activity. RESULTS: All medicaments decreased the initial bacterial load (P < .05). The highest bacterial reduction in the main canal and dentinal tubules was observed in the Ca(OCl)2 group (P < .05). TAP- or Ca(OH)2-treated dentin surface improved cell viability and ALP activity compared with the untreated dentin surface (P < .05), whereas Ca(OCl)2 decreased cell viability and ALP activity (P < .05). Ten percent ascorbic acid neutralized the effect of Ca(OCl)2 on the treated dentin surface, showing higher cell viability (P < .05) and similar ALP activity with the untreated dentin surface and the other groups (P > .05). CONCLUSIONS: Ca(OCl)2 medication improved root canal disinfection against E. faecalis biofilm compared with TAP and Ca(OH)2. The adverse effects caused by Ca(OCl)2 on cell viability and mineralization activity can be neutralized with 10% ascorbic acid.

Effect of benzalkonium chloride addition to EDTA on attachment and proliferation of dental pulp stem cells on dentin and on transforming growth factor-ß1 release.

To investigate the effect of benzalkonium chloride (BAC) addition to ethylenediaminetetraacetic acid (EDTA) on transforming growth factor-ß1 (TGF-ß1) release, as well as attachment and proliferation of dental pulp stem cells (DPSCs) on dentin. A total of standard 268 human dentin disks were prepared and immersed in 1.5% sodium hypochlorite (NaOCl) for 5 min. The disks were rinsed with distilled water and randomly divided into seven groups. In control group, the disks received no further treatment. The remaining disks were immersed in following solutions: 17% EDTA or 17% EDTA + 0.008% BAC for 1, 5 or 10 min and rinsed with distilled water. DPSCs were seeded in part of the disks since the TGF-ß1 release assay was performed with disks with and without cells. The attachment and proliferation of DPSCs on dentin disks were analyzed using lactate dehydrogenase activity and WST-1 assays, respectively. The cell morphology was observed by scanning electron microscopy. The release of TGF-ß1 was quantified using ELISA. Data were analyzed using three- and two-way analysis of variance with Bonferroni corrections. Both EDTA solutions increased the attachment and proliferation of DPSCs (p < .05) while there was no significant difference between them (p > .05). The exposure time of both EDTA solutions had no influence on cell attachment, proliferation and TGF-ß1 release (p > .05). There was no significant difference in TGF-ß1 release between the control and experimental groups (p > .05). The amount of released TGF-ß1 from dentin disks was similar whether or not they were seeded with cells (p > .05). Dentin treatment with either of the EDTA solutions had no effect on the amount of TGF-ß1 release while both EDTA solutions improved cell attachment and proliferation on dentin surface regardless of exposure time.

Effect of heat application on the physical properties and chemical structure of calcium silicate-based sealers.

OBJECTIVE: To determine the effect of heat application on the setting and chemical properties of HiFlow BC Sealer and compare to other calcium silicate (CSBS) and epoxy resin-based root canal sealers. MATERIALS AND METHODS: AH Plus, BioRoot RCS (BioRoot), Endosequence BC (Endosequence), and HiFlow BC (HiFlow) sealers were placed at 37 °C or subjected to heat at 200 °C for 10 or 30 s, followed by incubation at 37 °C in a humidified incubator during experiments. Setting time, viscosity, and flow were assessed, and changes in chemical structure were evaluated using the Fourier-transform infrared spectroscopy (FTIR). Thermogravimetric analysis was also used to evaluate the weight change (%) of the sealers upon heating from room temperature to 37 °C or 200 °C at a rate of 20 °C/min. Data were analyzed using a two-way ANOVA with a Bonferroni post-hoc test (p = 0.05). RESULTS: Application of heat extended the setting time for Endosequence and HiFlow but resulted in a faster setting of AH Plus and BioRoot. The highest flow and lower viscosity were observed in HiFlow at high temperature (p < 0.05), whereas the lowest flow with the highest viscosity and greatest weight loss were observed in BioRoot after heat application (p < 0.05). FTIR spectra demonstrated no changes to functional groups after heat application, except for the strong H-O-H absorption peak corresponding to water in BioRoot. CONCLUSIONS: Endosequence and HiFlow showed similar chemical properties with a higher flow and lower viscosity in HiFlow after heat application. Heat application resulted in reduced flow, increased viscosity, and weight loss for BioRoot. The setting of AH Plus was fastened with heat, while its weight loss, viscosity, and flow characteristics were stable. CLINICAL RELEVANCE: HiFlow, Endosequence, and AH Plus can be all used with WVC obturation techniques. Heat application resulted in minor changes in their physical properties including setting time, flow, weight loss, and chemical properties, while BioRoot showed a significant amount of weight loss, increase in viscosity, and reduced flowability after heat application.

Soft and Hard Tissue Remodeling after Endodontic Microsurgery: A Cohort Study.

INTRODUCTION: The aim of this study was to investigate the impact of the incision type, with or without a coronally repositioning flap (CRF), on soft tissue healing and crestal bone remodeling after endodontic microsurgery (EMS). METHODS: Clinical pictures and cone-beam computed tomography images from 47 patients (120 teeth) taken before surgery and at the follow-up appointment were included in this study. Clinical pictures were qualitatively evaluated by 2 endodontists for the gingival marginal level (GML) (recession, same position, or coronal root coverage), papillary height (same position/receded), and for presence/absence of scars for each tooth. Cone-beam computed tomography images were used to calculate the changes in the distance between the cementoenamel junction and the crestal bone level (CBL) between the preoperative and follow-up scans. Statistical analyses were performed to determine a correlation between patient-related factors (age, sex, tooth type, position, and presence/absence of a crown), incision techniques, and changes within the CBL. RESULTS: Gingival recession was more prevalent in mandibular teeth, molar teeth, and teeth that received intrasulcular or papilla-based incisions (P < .05). Scar formation was affected by the flap design (P < .05). CRF was the only technique resulting in coronal root coverage (P < .05). There were no changes observed in the papillary height between the various flap designs. There was also no statistically significant difference in the crestal bone height between the preoperative and follow-up scan measurements (P > .05). CONCLUSIONS: Soft tissue changes are evident after EMS and can be affected by the flap design selected, as well as the site being treated. Application of CRF can improve the position of GML after EMS. There are insignificant changes within the CBL at the facial aspect of the root after EMS.

Antimicrobial Activity and Biocompatibility of Antibiotic-Loaded Chitosan Hydrogels as a Potential Scaffold in Regenerative Endodontic Treatment.

INTRODUCTION: The objective of this study was to determine the effectiveness of several antibiotic-loaded hydrogel scaffolds against Enterococcus faecalis, as well as their ability to stimulate proliferation and mineralization of dental pulp stem cells. METHODS: Fibrin (Fg) or chitosan-fibrin hydrogels (Ch) were prepared using 12.5 mg/mL fibrinogen and 0.4% (w/v) chitosan. Triple antibiotics, clindamycin-modified triple antibiotic paste, or double antibiotics were loaded in gels (1 mg/mL). Antibacterial effect against E. faecalis biofilm was determined by using colony-forming units (CFUs) and confocal laser scanning microscope (CLSM). Cell viability and morphology were determined by loading cells into different gels at 7 and 14 days using the water-soluble tetrazolium salt-1 cell viability assay and Live & Dead cell analysis. Mineralization was detected by using alkaline phosphatase and alizarin red staining activity. RESULTS: Antibiotic-loaded Fg gel and Ch gel alone without antibiotics resulted in a significant reduction in CFUs compared with the positive control (P < .05). When antibiotics were loaded in Ch gel, there were no CFUs detected in any groups (P < .05). CLSM images showed dense red areas with mostly dead bacteria on the dentin surface in antibiotic-loaded Ch groups, which showed significantly less live bacteria compared with the other groups (P < .05). Triple antibiotic-loaded Fg and Ch gels resulted in a dramatic decrease in the mineralized nodule formation compared with all other gel groups (P < .05). Ch hydrogels resulted in round cell morphology up to 7 days. Ch alone or with double antibiotic paste showed more cell spreading with spindle-shaped morphology at 14 days and higher alkaline phosphatase activity compared with other antibiotic-loaded Ch groups (P > .05). CONCLUSIONS: Double antibiotic-loaded Ch gel appears to enhance the antibacterial properties while maintaining higher cell viability, cell spreading, and mineralization activity, compared with all the other scaffolds investigated.

Dentin Conditioning Protocol for Regenerative Endodontic Procedures.

INTRODUCTION: This study focused on the optimization of sodium hypochlorite-EDTA irrigation in terms of the viability and morphology of dental pulp stem cells (DPSCs) and the effects of an optimized EDTA protocol alone or prepared with nanobubble (NB) water on cell behavior. METHODS: In the first part, human dentin discs were conditioned with the following protocols: (1) Sodium hypochlorite followed by phosphate-buffered saline (PBS), (2) Irrigation protocol from group 1 followed by EDTA, (3) Irrigation protocol from group 2 followed by PBS, (4) Sodium hypochlorite followed by EDTA, (5) Irrigation protocol from group 4 followed by PBS. DPSC viability and morphology were determined. In the second part, dentin discs were conditioned with the (1) optimized protocol in the first part, (2) EDTA prepared using NB water, (3) ultrasonic-activated EDTA, or (4) ultrasonic-activated EDTA prepared using NB water. Transforming growth factor beta release and DPSC viability, morphology, and migration were determined using the enzyme-linked immunosorbent assay, the water-soluble tetrazolium salt-1 cell viability assay and live-dead assay, and the transwell migration assay, respectively. Data were analyzed using Kruskal-Wallis or one-way analysis of variance and post hoc tests. RESULTS: The highest cell viability was observed in group 3 followed by group 5 (P < .05) in which PBS was used as a final rinse. Irrigation protocol from group 3 was used for the subsequent experiments. Ultrasonic-activated EDTA improved transforming growth factor beta release, viability, and migration of the cells compared with EDTA (P < .05). The preparation of EDTA with NBs did not change the biological properties of the EDTA-conditioned dentin (P > .05). CONCLUSIONS: Removing the residual EDTA using PBS improved the cell viability on the dentin surface. Ultrasonic activation enhanced the growth factor release and biological properties, whereas the preparation of EDTA with NBs showed a similar effect to regular EDTA without compromising the cellular effect.

Effect of ultrasonic activation on dentinal tubule penetration of calcium silicate-based cements.

This study investigated the dentinal tubule penetration of mineral trioxide aggregate (MTA), NeoMTA Plus and Biodentine placed by either manual condensation or ultrasonic activation in simulated open apex model. Standardized divergent open apex models were created using palatal roots of 60 human maxillary molars and divided into six groups according to the used cements and activation methods (n = 10): MTA-manual condensation, MTA-ultrasonic activation, NeoMTA Plus-manual condensation, NeoMTA Plus-ultrasonic activation, Biodentine-manual condensation, Biodentine-ultrasonic activation. For the measurement of penetration, the cements were mixed with 0.1% Rhodamin B and 6-mm apical portions of each root canal were obturated in an orthograde direction. The roots were embedded into acrylic blocks, and 1-mm-thick sections were obtained at 3 mm from the apex. Specimens were mounted onto glass slides and scanned under a confocal laser scanning microscope (CLSM) and stereomicroscope. Dentinal tubule penetration areas, depth and percentage were measured using LSM and ImageJ software. The data were analyzed using two-way analysis of variance (anova) with Bonferroni correction (α = 0.05). No correlation was found between stereomicroscope and CLSM analyses (p > .05). CLSM analysis showed no significant differences between MTA, NeoMTA Plus, and Biodentine groups when manual condensation was used (p > .05). Ultrasonic activation did not increase the tubular penetration of MTA, NeoMTA Plus or Biodentine as compared to manual condensation of each material (p > .05). MTA, NeoMTA Plus and Biodentine showed similar tubular penetration when manual condensation was used. Ultrasonic activation of these cements had no effect on tubular penetration of each material as compared to the manual condensation counterparts.

Obturation quality of calcium silicate-based cements placed with different techniques in teeth with perforating internal root resorption: a micro-computed tomographic study.

OBJECTIVES: To evaluate and compare the obturation quality of mineral trioxide aggregate (MTA) and Biodentine placed with hand condensation or indirect ultrasonic activation technique in teeth models simulating perforating internal root resorption (IRR) using micro-computed tomographic (micro-CT) imaging. MATERIALS AND METHODS: Standardized models with perforating IRR cavities were created using 40 extracted single-rooted human teeth and randomly divided into four groups (n = 10). The specimens were obturated with either MTA or Biodentine and the placement technique applied was either hand condensation or indirect ultrasonic activation. Micro-CT scans were performed for the volumetric analysis of voids and filling materials in the resorption cavities and apical portion of the specimens. Data were analyzed using one-way analysis of variance and paired t test. RESULTS: No significant difference was observed between the groups in terms of the percentage volume of filling materials (p > 0.05). The apical portion of the specimens significantly presented less percentage volume of filling materials than the resorption cavities in each group (p < 0.05). CONCLUSIONS: No placement technique produced void-free fillings in teeth with perforating IRR. There was no significant difference between the obturation quality of Biodentine and MTA. The obturation quality in the apical portion of the root canals was inferior than that in the resorption cavities. CLINICAL RELEVANCE: The obturation of the apical region of teeth with perforating IRR is challenging irrespective of the material type and placement technique.

Surface and vertical dimensional changes of mineral trioxide aggregate and biodentine in different environmental conditions

Abstract Surface changes in biological environments are critical for the evaluation of physical and biological activity of biomaterials. Objective: This study investigated surface alterations of calcium silicate-based cements after exposure to different environments. Material and Methods: Forty-eight cylindrical cavities were prepared on root surfaces. The cavities were filled using ProRoot MTA or Biodentine and assigned to four subgroups (n=6): dry, wet, acidic, and blood. Surface topographies were evaluated using an optical profilometer for 28 days, and the roughness of the material surfaces was quantified. Vertical dimensional change was measured by determining the height difference between the material surface and the flat tooth surface. Data were compared with a two-way repeated measures ANOVA and Bonferroni tests. Results: In dry condition, the surface roughness of MTA or Biodentine was constant up to 3 days (p>0.05) but decreased after 28 days (p<0.05). In dry condition, ProRoot MTA presented constant surface level through time, while Biodentine showed decreased surface level after 28 days. In wet condition, the roughness and the surface levels of both materials increased after 1 day (p<0.05). Neither the surface roughness nor the levels of the materials showed significant changes in acidic conditions (p>0.05). Both materials showed the highest roughness in blood conditions on the 1st day (p<0.05), while the surface roughness in blood decreased dramatically after 28 days. The roughness of Biodentine was higher in wet conditions up to 3 days compared with ProRoot MTA (p<0.05). Likewise, in blood condition, Biodentine showed higher roughness on the 28th day than ProRoot MTA (p<0.05). Conclusions: Dry, wet, and blood conditions had a time-dependent effect on the surface roughness and vertical dimensional changes of the materials. However, acidic conditions did not affect the roughness and the surface level of the materials.

Surface and vertical dimensional changes of mineral trioxide aggregate and biodentine in different environmental conditions.

OBJECTIVES: Surface changes in biological environments are critical for the evaluation of physical and biological activity of biomaterials. Objective: This study investigated surface alterations of calcium silicate-based cements after exposure to different environments. MATERIAL AND METHODS: Material and Methods: Forty-eight cylindrical cavities were prepared on root surfaces. The cavities were filled using ProRoot MTA or Biodentine and assigned to four subgroups (n=6): dry, wet, acidic, and blood. Surface topographies were evaluated using an optical profilometer for 28 days, and the roughness of the material surfaces was quantified. Vertical dimensional change was measured by determining the height difference between the material surface and the flat tooth surface. Data were compared with a two-way repeated measures ANOVA and Bonferroni tests. RESULTS: Results: In dry condition, the surface roughness of MTA or Biodentine was constant up to 3 days (p>0.05) but decreased after 28 days (p<0.05). In dry condition, ProRoot MTA presented constant surface level through time, while Biodentine showed decreased surface level after 28 days. In wet condition, the roughness and the surface levels of both materials increased after 1 day (p<0.05). Neither the surface roughness nor the levels of the materials showed significant changes in acidic conditions (p>0.05). Both materials showed the highest roughness in blood conditions on the 1st day (p<0.05), while the surface roughness in blood decreased dramatically after 28 days. The roughness of Biodentine was higher in wet conditions up to 3 days compared with ProRoot MTA (p<0.05). Likewise, in blood condition, Biodentine showed higher roughness on the 28th day than ProRoot MTA (p<0.05). CONCLUSIONS: Conclusions: Dry, wet, and blood conditions had a time-dependent effect on the surface roughness and vertical dimensional changes of the materials. However, acidic conditions did not affect the roughness and the surface level of the materials.

A Miniature Swine Model for Stem Cell-Based De Novo Regeneration of Dental Pulp and Dentin-Like Tissue.

The goal of this study was to establish mini-swine as a large animal model for stem cell-based pulp regeneration studies. Swine dental pulp stem cells (sDPSCs) were isolated from mini-swine and characterized in vitro. For in vivo studies, we first employed both ectopic and semi-orthotopic study models using severe combined immunodeficiency mice. One is hydroxyapatite-tricalcium phosphate (HA/TCP) model for pulp-dentin complex formation, and the other is tooth fragment model for complete pulp regeneration with new dentin depositing along the canal walls. We found that sDPSCs are similar to their human counterparts exhibiting mesenchymal stem cell characteristics with ability to form colony forming unit-fibroblastic and odontogenic differentiation potential. sDPSCs formed pulp-dentin complex in the HA/TCP model and showed pulp regeneration capacity in the tooth fragment model. We then tested orthotopic pulp regeneration on mini-swine including the use of multi-rooted teeth. Using autologous sDPSCs carried by hydrogel and transplanted into the mini-swine root canal space, we observed regeneration of vascularized pulp-like tissue with a layer of newly deposited dentin-like (rD) tissue or osteodentin along the canal walls. In some cases, dentin bridge-like structure was observed. Immunohistochemical analysis detected the expression of nestin, dentin sialophosphoprotein, dentin matrix protein 1, and bone sialoprotein in odontoblast-like cells lining against the produced rD. We also tested the use of allogeneic sDPSCs for the same procedures. Similar findings were observed in allogeneic transplantation. This study is the first to show an establishment of mini-swine as a suitable large animal model utilizing multi-rooted teeth for further cell-based pulp regeneration studies.

Comparison of sodium hypochlorite extrusion by five irrigation systems using an artificial root socket model and a quantitative chemical method.

OBJECTIVES: This is to compare the volumes of irrigant apically extruded by five irrigation systems in an artificial socket model simulating clinical conditions. MATERIALS AND METHODS: Twenty extracted human single-rooted teeth were enlarged to size 40/04 and then embedded in silicone impression material. The root canal space was irrigated with nominal 3% sodium hypochlorite (NaOCl) using standard needle irrigation (SNI) with a 30-gauge notched needle, EndoActivator (EA), XP Endo Finisher (XP Endo), EndoVac (EV), and photon-induced photoacoustic streaming (PIPS). Extruded NaOCl was collected, reacted with taurine to form taurine-monochloramine, and absorbance of taurine-monochloramine was measured at 252 nm using a spectrophotometer. The five irrigation systems were compared with repeated measures ANOVA and pairwise comparisons. RESULTS: The EV group had very low extrusion (mean ± SD = 0.12 ± 0.2 µL) and differed significantly from the other four groups (P ≤ 0.001). Larger volumes of irrigant were extruded in the other irrigation groups. There were no significant differences in the extruded volumes among the SNI (7.4 ± 3.4 µL), EA (7.0 ± 6.1 µL), and XP Endo (7.8 ± 4.1 µL) groups (P = 1). The PIPS group had the highest mean extruded volume (12.9 ± 6.8 µL) and differed significantly from SNI (P = 0.030), EV (P < 0.0005), and EA (P = 0.02), but not XP Endo (P = 0.154). CONCLUSION: Under the in vitro conditions of this study, irrigant extrusion appears unavoidable unless negative pressure irrigation such as EV is used. PIPS extrudes more irrigant than other systems, while SNI, EA, and XP Endo extrude similar volumes of irrigant. CLINICAL RELEVANCE: The findings help clinicians select the optimal irrigation system to avoid irrigant extrusion.

Concentration and time-dependent effect of initial sodium hypochlorite on the ability of QMix and ethylenediaminetetraacetic acid to remove smear layer.

AIMS: The aim of this study was to compare the ability of 17% ethylenediaminetetraacetic acid (EDTA) and QMix with different concentrations and time exposures of initial sodium hypochlorite (NaOCl) to remove the smear layer from the root canals. MATERIALS AND METHODS: Eighty maxillary central incisors were used. After instrumentation, the teeth were divided into eight experimental groups according to the initial and final rinse. About 2.5% and 5% NaOCl were used during instrumentation and for 1 or 3 min was used as postinstrumentation initial irrigants, and 17% EDTA and QMix used as final irrigants. The apical and middle parts of the specimens were observed by scanning electron microscope. STATISTICAL ANALYSIS USED: Data were analyzed using the Kruskal-Wallis, Mann-Whitney, and Friedman's test. RESULTS: Regardless of the type of final irrigant, QMix allowed more smear layer removal than EDTA after using 5% initial NaOCl for 3 min. In the apical part of the root canal walls, the smear layer was not completely removed. CONCLUSION: QMix and EDTA were similarly effective in smear layer removal at the middle parts of the root canal regardless of the concentration and time exposure of initial NaOCl, while none of the irrigation protocols was able to remove smear layer at the apical parts.

Efficacy of different irrigant protocols and application systems on sealer penetration using a stepwise CLSM analysis.

This study compared several irrigation protocols and application systems for sealer penetration into dentinal tubules. Single-rooted-human teeth were divided into 5 experimental groups (n = 15) and a control group (n = 5), according to final irrigation protocols: standard needle irrigation (SNI); Vibringe; Vibringe + NaviTip FX (Vibringe NFX); Endo Spray (ES); and passive-ultrasonic-irrigation (PUI). Following obturation of the root canals, the percentage of the sealer penetration was measured at different depths using stepwise CLSM analysis. The sealer penetration in the experimental groups was significantly higher than the control group at all levels (p < .05). No significant differences were observed between Vibringe and SNI or Vibringe NFX, ES, and PUI at all depths (p > .05). The Vibringe NFX, ES, and PUI groups allowed deeper sealer penetration than SNI at 100, 250, and 500 µm levels (p < .05). The irrigant activation, the needle design, and the application form (syringe or spray) may impact the quality of the seal that is achieved with root canal filling.

Combined Effects of Vascular Endothelial Growth Factor and Bone Morphogenetic Protein 2 on Odonto/Osteogenic Differentiation of Human Dental Pulp Stem Cells In Vitro.

INTRODUCTION: The purpose of this study was to investigate whether combined and concerted delivery of vascular endothelial growth factor (VEGF) and bone morphogenetic protein 2 (BMP-2) enhances odonto/osteogenic differentiation of human dental pulp stem cells (DPSCs) in vitro. METHODS: Various concentrations of VEGF and/or BMP-2 with or without the presence of odonto/osteogenic medium (OM) were added into DPSC cultures for 21 days. The mineral formation in cultures was evaluated using alizarin red stain (ARS). Optimal concentrations of VEGF and BMP-2 were codelivered to DPSCs for total of 21 days with the following experimental groups: (1) group 1: OM only, (2) group 2: OM + VEGF, (3) group 3: OM + BMP-2, and (4) group 4: OM + VEGF + BMP-2 (subgroup 4a: VEGF present the first 7 days, 4b: BMP-2 present the last 14 days, and 4c, both present for 21 days). Cultures were then subjected to quantitative ARS analysis or harvested for quantitative polymerase chain reaction analysis for the expression of core-binding factor alpha 1 (CBFA1), alkaline phosphatase (ALP), and dentin matrix protein 1 (DMP-1). RESULTS: No mineral formation was detected by ARS when VEGF and/or BMP-2 were used without OM. OM + VEGF, but not OM + BMP-2, formed more mineralization than OM (P < .05). In the codelivery groups, the highest mineralization was observed in OM + VEGF and subgroup 4a compared with OM or the other groups (P < .05). Quantitative polymerase chain reaction analysis showed that CBFA1, ALP, and DMP-1 levels were higher in groups 2, 3, and 4a compared with 4b and 4c (P < .05). CBFA1 expressed higher in groups 2, 3, and 4a compared with OM (P < .05). For ALP expression, only subgroup 4a expressed higher than OM (P < .05). No difference was detected between groups 2 and 3 (P > .05) in the expression of the 3 genes. CONCLUSIONS: VEGF addition in the early phase rather than a continuous presence of both VEGF and BMP-2 enhances odonto/osteogenic differentiation of DPSCs.