Effect of 3D-printed polycaprolactone/osteolectin scaffolds on the odontogenic differentiation of human dental pulp cells.

Cell-based tissue engineering often requires the use of scaffolds to provide a three-dimensional (3D) framework for cell proliferation and tissue formation. Polycaprolactone (PCL), a type of polymer, has good printability, favorable surface modifiability, adaptability, and biodegradability. However, its large-scale applicability is hindered by its hydrophobic nature, which affects biological properties. Composite materials can be created by adding bioactive materials to the polymer to improve the properties of PCL scaffolds. Osteolectin is an odontogenic factor that promotes the maintenance of the adult skeleton by promoting the differentiation of LepR+ cells into osteoblasts. Therefore, the aim of this study was to evaluate whether 3D-printed PCL/osteolectin scaffolds supply a suitable microenvironment for the odontogenic differentiation of human dental pulp cells (hDPCs). The hDPCs were cultured on 3D-printed PCL scaffolds with or without pores. Cell attachment and cell proliferation were evaluated using EZ-Cytox. The odontogenic differentiation of hDPCs was evaluated by alizarin red S staining and alkaline phosphatase assays. Western blot was used to evaluate the expression of the proteins DSPP and DMP-Results: The attachment of hDPCs to PCL scaffolds with pores was significantly higher than to PCL scaffolds without pores. The odontogenic differentiation of hDPCs was induced more in PCL/osteolectin scaffolds than in PCL scaffolds, but there was no statistically significant difference. 3D-printed PCL scaffolds with pores are suitable for the growth of hDPCs, and the PCL/osteolectin scaffolds can provide a more favorable microenvironment for the odontogenic differentiation of hDPCs.

Icariin negatively regulated lipopolysaccharide-induced inflammation and ameliorated the odontogenic activity of human dental pulp cells in vitro.

Alleviating inflammation and promoting dentine regeneration is critical for the healing of pulpitis. In this study, we investigated the anti-inflammatory, angiogenesis and odontogenesis function of icariin on Human dental pulp cells (HDPCs) under inflammatory state. Furthermore, the underlying mechanisms was also evaluated. Icariin attenuated the LPS-induced pro-inflammatory marker expression, such as interleukin-1ß (IL-1ß), IL-6 and IL-8. The immunoblotting and immunofluorescence staining results showed that icariin suppressed the inflammatory responses mediated by the protein kinase B (Akt) and nuclear factor kappa-B (NF-κB) signaling cascades. Additionally, icariin also upregulated the expression of odontogenic and angiogenic genes and proteins (namely dentin sialophosphoprotein (DSPP), dentin matrix protein 1 (DMP1), anti-collagen Ⅰ (COL-Ⅰ), and vascular endothelial growth factor (VEGF) and fibroblast growth factor-1 (FGF-1)), alkaline phosphatase activity, and calcium nodule deposition in LPS-exposed HDPCs. In a word, our findings indicated that icariin attenuated pulp inflammation and promoted odontogenic and angiogenic differentiation in the inflammatory state. Icariin may be a promising vital pulp therapy agent for the regenerative treatment of the inflamed dental pulp.

A comparison of osteogenic effect of newly manufactured calcium silicate-based sealers in vitro.

This study aimed to assess the effect of different calcium silicate-based root canal sealers (CSRS) on osteogenic effect in human periodontal ligament cells (hPDLCs). hPDLCs were cultured in a medium containing extract of 5 types of CSRS. The specimens were assessed by the cell cytotoxicity test, alkaline phosphatase staining, alizarin red S staining, quantitative real-time PCR, Western blot analysis, and enzyme-linked immunosorbent assay. The diluted concentrations of extracted solutions had no significant effect on the viability of hPDLCs. There was a statistically significant difference in the mRNA expression level of bone sialoprotein (BSP), osteocalcin (OCN), and runt-related transcription factor 2 (RUNX2) among some groups. The protein expressions of BSP, OCN, and RUNX2 were significantly higher in some groups compared to the control group. The CSRS did not interfere with the osteogenic differentiation of hPDLCs, compared to the control group. CSRS are shown to have biocompatibility and osteogenic differentiation effect on hPDLCs.

Extended and adjustable field-of-view of variable interscan time analysis by ammonite-scanning swept-source optical coherence tomography angiography.

A novel scanning protocol, ammonite scan, is proposed for widefield optical coherence tomography angiography (OCTA) and relative retinal blood flow velocity imaging in the human retina using variable interscan time analysis (VISTA). A repeated circle scan using a 400 kHz swept-source was employed to achieve an interscan time of 1.28 ms. The center of the repeated circular scan continuously moved spirally towards the peripheral region, ensuring an extended and adjustable scan range while preserving the short interscan time. Image artifacts due to eye movement were eliminated via extra motion-correction processing using data redundancy. The relative blood flow velocity in superficial and deep plexus layers was calculated from the VISTA image, and their ratio was used to explore the microvascular flow parameter in the healthy human eye.

Osteolectin Promotes Odontoblastic Differentiation in Human Dental Pulp Cells.

INTRODUCTION: Osteolectin is a secreted glycoprotein of the C-type lectin domain superfamily, expressed in bone tissues and is reported as a novel osteogenic factor that promotes bone regeneration. However, the effect of osteolectin on human dental pulp cells (hDPCs) has not been reported. Therefore, we aimed to investigate the odontoblastic differentiation of osteolectin in hDPCs and further attempt to reveal its underlying mechanism. METHODS: Cytotoxicity assays were used to detect the cytotoxicity of osteolectin. The odontoblastic differentiation of hDPCs and its underlying mechanisms were measured by the alkaline phosphatase (ALP) activity, mineralized spots formation, and the gene and protein expression of odontoblastic differentiation through ALP staining, Alizarin red S staining, quantitative real-time polymerase chain reaction, and Western blot analysis, respectively. RESULTS: WST-1 assay showed osteolectin at concentrations below 300 ng/ml was noncytotoxic and safe for hDPCs. The following experiment demonstrated that osteolectin could increase ALP activity, accelerate the mineralization process, and up-regulate the odontogenic differentiation markers in both gene and protein levels (P < .05). Osteolectin stimulated the phosphorylation of ERK, JNK, and Protein kinase B (AKT) in hDPCs. Extracellular signal-regulated kinase (ERK), Jun N-terminal kinase (JNK), and AKT inhibitors decreased ALP activity and mineralization capacity and suppressed the expression of dentin sialophosphoprotein and dentin matrix protein-1. CONCLUSION: Osteolectin can promote odontoblastic differentiation of hDPCs, and the whole process may stimulate ERK, JNK, and AKT signaling pathways by increasing p-ERK, p-JNK, and p-AKT signals.

Retinal blood flow speed quantification at the capillary level using temporal autocorrelation fitting OCTA [Invited].

Optical coherence tomography angiography (OCTA) can visualize vasculature structures, but provides limited information about blood flow speed. Here, we present a second generation variable interscan time analysis (VISTA) OCTA, which evaluates a quantitative surrogate marker for blood flow speed in vasculature. At the capillary level, spatially compiled OCTA and a simple temporal autocorrelation model, ρ(τ) = exp(-ατ), were used to evaluate a temporal autocorrelation decay constant, α, as the blood flow speed marker. A 600 kHz A-scan rate swept-source OCT prototype instrument provides short interscan time OCTA and fine A-scan spacing acquisition, while maintaining multi mm2 field of views for human retinal imaging. We demonstrate the cardiac pulsatility and assess repeatability of α measured with VISTA. We show different α for different retinal capillary plexuses in healthy eyes and present representative VISTA OCTA in eyes with diabetic retinopathy.

Effects of CTHRC1 on odontogenic differentiation and angiogenesis in human dental pulp stem cells.

Objectives: This study aimed to determine whether collagen triple helix repeat containing-1 (CTHRC1), which is involved in vascular remodeling and bone formation, can stimulate odontogenic differentiation and angiogenesis when administered to human dental pulp stem cells (hDPSCs). Materials and Methods: The viability of hDPSCs upon exposure to CTHRC1 was assessed with the WST-1 assay. CTHRC1 doses of 5, 10, and 20 µg/mL were administered to hDPSCs. Reverse-transcription polymerase reaction was used to detect dentin sialophosphoprotein, dentin matrix protein 1, vascular endothelial growth factor, and fibroblast growth factor 2. The formation of mineralization nodules was evaluated using Alizarin red. A scratch wound assay was conducted to evaluate the effect of CTHRC1 on cell migration. Data were analyzed using 1-way analysis of variance followed by the Tukey post hoc test. The threshold for statistical significance was set at p < 0.05. Results: CTHRC1 doses of 5, 10, and 20 µg/mL had no significant effect on the viability of hDPSCs. Mineralized nodules were formed and odontogenic markers were upregulated, indicating that CTHRC1 promoted odontogenic differentiation. Scratch wound assays demonstrated that CTHRC1 significantly enhanced the migration of hDPSCs. Conclusions: CTHRC1 promoted odontogenic differentiation and mineralization in hDPSCs.

Ultrahigh Resolution OCT Markers of Normal Aging and Early Age-related Macular Degeneration.

Purpose: Ultrahigh resolution spectral domain-OCT (UHR SD-OCT) enables in vivo visualization of micrometric structural markers which differentially associate with normal aging versus age-related macular degeneration (AMD). This study explores the hypothesis that UHR SD-OCT can detect and quantify sub-retinal pigment epithelium (RPE) deposits in early AMD, separating AMD pathology from normal aging. Design: Prospective cross-sectional study. Participants: A total of 53 nonexudative (dry) AMD eyes from 39 patients, and 63 normal eyes from 39 subjects. Methods: Clinical UHR SD-OCT scans were performed using a high-density protocol. Exemplary high-resolution histology and transmission electron microscopy images were obtained from archive donor eyes. Three trained readers evaluated and labeled outer retina morphological features, including the appearance of a hyporeflective split within the RPE-RPE basal lamina (RPE-BL)-Bruch's membrane (BrM) complex on UHR brightness (B)-scans. A semi-automatic segmentation algorithm measured the thickness of the RPE-BL-BrM split/hyporeflective band. Main Outcome Measures: Qualitative description of outer retinal morphological changes on UHR SD-OCT B-scans; the proportion of the RPE-BL-BrM complex with visible split (%) and the thickness of the resulting hyporeflective band (µm). Results: In young normal eyes, UHR SD-OCT consistently revealed an RPE-BL-BrM split/hyporeflective band. Its visibility and thickness were less in eyes of advanced age. However, the split/hyporeflective band was again visible in early AMD eyes. Both qualitative reading and quantitative thickness measurements showed significantly elevated visibility and thickness of the RPE-BL-BrM split/hyporeflective in early AMD eyes compared to age-matched controls. Conclusions: Our imaging results strongly support the hypothesis that appearance of the RPE-BL-BrM split/hyporeflective band in older subjects is dominated by the BL deposit, an indicator of early AMD well known from histology. Ultrahigh resolution SD-OCT can be used to investigate physiological aging as well as early AMD pathology in clinical imaging studies. Developing quantifiable markers associated with disease pathogenesis and progression can facilitate drug discovery, as well as reduce clinical trial times. Financial Disclosures: Proprietary or commercial disclosure may be found after the references.

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.

Perfusable micro-vascularized 3D tissue array for high-throughput vascular phenotypic screening.

Microfluidic organ-on-a-chip technologies have enabled construction of biomimetic physiologically and pathologically relevant models. This paper describes an injection molded microfluidic platform that utilizes a novel sequential edge-guided patterning method based on spontaneous capillary flow to realize three-dimensional co-culture models and form an array of micro-vascularized tissues (28 per 1 × 2-inch slide format). The MicroVascular Injection-Molded Plastic Array 3D Culture (MV-IMPACT) platform is fabricated by injection molding, resulting in devices that are reliable and easy to use. By patterning hydrogels containing human umbilical endothelial cells and fibroblasts in close proximity and allowing them to form vasculogenic networks, an array of perfusable vascularized micro-tissues can be formed in a highly efficient manner. The high-throughput generation of angiogenic sprouts was quantified and their uniformity was characterized. Due to its compact design (half the size of a 96-well microtiter plate), it requires small amount of reagents and cells per device. In addition, the device design is compatible with a high content imaging machine such as Yokogawa CQ-1. Furthermore, we demonstrated the potential of our platform for high-throughput phenotypic screening by testing the effect of DAPT, a chemical known to affect angiogenesis. The MV-IMPACT represent a significant improvement over our previous PDMS-based devices in terms of molding 3D co-culture conditions at much higher throughput with added reliability and robustness in obtaining vascular micro-tissues and will provide a platform for developing applications in drug screening and development.

Odontogenic Effect of Icariin on the Human Dental Pulp Cells.

Background and Objectives: Human dental pulp cells (HDPCs) can be used for dentin regeneration due to its odontogenic differentiation property. Icariin can induce osteogenic differentiation of stem cells. However, its potential to induce odontogenic differentiation of HDPCs remains unclear. Thus, the aim of this study was to evaluate the capacity of icariin to induce odontogenic differentiation of HDPCs and investigate the underlying molecular mechanism. Materials and Methods: Cell viability assay was used to detect the cytotoxicity of icariin to HDPCs. Effect of icariin on HDPCs chemotaxis was measured by scratch migration assay. The mineralized and odontogenic differentiation of HDPCs was assessed by alkaline phosphatase (ALP) staining, alizarin red S (ARS) staining, real-time PCR, and Western blot of dentin matrix protein 1 (DMP 1) and dentin sialophosphoprotein (DSPP). In addition, Mitogen-activated protein kinase (MAPK) signaling pathway of icariin-induced biomineralization was investigated by Western blot. Results: Cells treated with icariin at all concentrations tested maintained viability, indicating that icariin was biocompatible. Icariin accelerated HDPCs chemotaxis (p < 0.05). Expression levels of related odontogenic markers were increased in the presence of icariin (p < 0.05). Icariin-induced odontogenic differentiation occurred via activation of the MAPK signaling pathway. Furthermore, MAPK inhibitors suppressed expression levels of DSPP and DMP 1 protein, ALP activity, and mineralization of HDPCs. Conclusions: Icariin can upregulate odontogenic differentiation of HDPCs by triggering the MAPK signaling pathway.

The Effects of 3-Dimensional Bioprinting Calcium Silicate Cement/Methacrylated Gelatin Scaffold on the Proliferation and Differentiation of Human Dental Pulp Stem Cells.

A calcium silicate cement/methacrylated gelatin (GelMa) scaffold has been applied in tissue engineering; however, the research on its applications in dental tissue regeneration remains lacking. We investigate the effect of this scaffold on human dental pulp stem cells (hDPSCs). hDPSCs were cultured in 3D-printed GelMa and MTA-GelMa scaffolds. Cell adhesion was evaluated using scanning electron microscopy images. Cells were cultured in an osteogenic differentiation medium, which contained a complete medium or α-MEM containing aqueous extracts of the 3D-printd GelMa or MTA-GelMa scaffold with 2% FBS, 10 mM ß-glycerophosphate, 50 µg/mL ascorbic acid, and 10 nM dexamethasone; cell viability and differentiation were shown by WST-1 assay, Alizarin Red S staining, and alkaline phosphatase staining. Quantitative real-time PCR was used to measure the mRNA expression of DSPP and DMP-1. One-way analysis of variance followed by Tukey's post hoc test was used to determine statistically significant differences, identified at p < 0.05. hDPSCs adhered to both the 3D-printed GelMa and MTA-GelMa scaffolds. There was no statistically significant difference between the GelMa and MTA-GelMa groups and the control group in the cell viability test. Compared with the control group, the 3D-printed MTA-GelMa scaffold promoted the odontogenic differentiation of hDPSCs. The 3D-printed MTA-GelMa scaffold is suitable for the growth of hDPSCs, and the scaffold extracts can better promote odontoblastic differentiation.

High speed, long range, deep penetration swept source OCT for structural and angiographic imaging of the anterior eye.

This study reports the development of prototype swept-source optical coherence tomography (SS-OCT) technology for imaging the anterior eye. Advances in vertical-cavity surface-emitting laser (VCSEL) light sources, signal processing, optics and mechanical designs, enable a unique combination of high speed, long range, and deep penetration that addresses the challenges of anterior eye imaging. We demonstrate SS-OCT with a 325 kHz A-scan rate, 12.2 µm axial resolution (in air), and 15.5 mm depth range (in air) at 1310 nm wavelength. The ultrahigh 325 kHz A-scan rate not only facilitates biometry measurements by minimizing acquisition time and thus reducing motion, but also enables volumetric OCT for comprehensive structural analysis and OCT angiography (OCTA) for visualizing vasculature. The 15.5 mm (~ 11.6 mm in tissue) depth range spans all optical surfaces from the anterior cornea to the posterior lens capsule. The 1310 nm wavelength range enables structural OCT and OCTA deep in the sclera and through the iris. Achieving high speed and long range requires linearizing the VCSEL wavenumber sweep to efficiently utilize analog-to-digital conversion bandwidth. Dual channel recording of the OCT and calibration interferometer fringe signals, as well as sweep to sweep wavenumber compensation, is used to achieve invariant 12.2 µm (~ 9.1 µm in tissue) axial resolution and optimum point spread function throughout the depth range. Dynamic focusing using a tunable liquid lens extends the effective depth of field while preserving the lateral resolution. Improved optical and mechanical design, including parallax "split view" iris cameras and stable, ergonomic patient interface, facilitates accurate instrument positioning, reduces patient motion, and leads to improved imaging data yield and measurement accuracy. We present structural and angiographic OCT images of the anterior eye, demonstrating the unique imaging capabilities using representative scanning protocols which may be relevant to future research and clinical applications.

Aspiration-mediated hydrogel micropatterning using rail-based open microfluidic devices for high-throughput 3D cell culture.

Microfluidics offers promising methods for aligning cells in physiologically relevant configurations to recapitulate human organ functionality. Specifically, microstructures within microfluidic devices facilitate 3D cell culture by guiding hydrogel precursors containing cells. Conventional approaches utilize capillary forces of hydrogel precursors to guide fluid flow into desired areas of high wettability. These methods, however, require complicated fabrication processes and subtle loading protocols, thus limiting device throughput and experimental yield. Here, we present a swift and robust hydrogel patterning technique for 3D cell culture, where preloaded hydrogel solution in a microfluidic device is aspirated while only leaving a portion of the solution in desired channels. The device is designed such that differing critical capillary pressure conditions are established over the interfaces of the loaded hydrogel solution, which leads to controlled removal of the solution during aspiration. A proposed theoretical model of capillary pressure conditions provides physical insights to inform generalized design rules for device structures. We demonstrate formation of multiple, discontinuous hollow channels with a single aspiration. Then we test vasculogenic capacity of various cell types using a microfluidic device obtained by our technique to illustrate its capabilities as a viable micro-manufacturing scheme for high-throughput cellular co-culture.

Anti-Inflammatory and Mineralization Effects of Bromelain on Lipopolysaccharide-Induced Inflammation of Human Dental Pulp Cells.

Background and Objectives: Bromelain is a mixture of protease obtained from pineapple fruits or stems. Even though the biological mechanism of action of bromelain has not been completely understood, it is well known that bromelain possesses anticancer, anti-inflammatory and immunomodulatory effects. This study investigated the anti-inflammatory effects of bromelain on lipopolysaccharide (LPS)-induced human dental pulp cells (hDPCs). Materials and Methods: Cell viability after bromelain treatment was measured using WST-1 assay. We exposed hDPCs to 5 µg/mL of LPS with 2.5 or 5 µg/mL of bromelain. We performed reverse-transcription polymerase chain reaction and enzyme-linked immunosorbent assay to detect interleukin-1ß, interleukin-6, and interleukin-8 levels. Western blots were used to detect intercellular adhesion molecules-1 (ICAM-1) and vascular cell adhesion molecules-1 (VCAM-1) levels. Immunofluorescence staining and Western blots were used to determine bromelain's anti-inflammatory mechanism. We also performed alkaline phosphatase and Alizarin red staining to verify mineralization nodule formation. Results: Bromelain at 2.5, 5, 10, or 20 µg/mL did not affect the viability of hDPCs significantly. LPS increased interleukin-1ß, interleukin-6, interleukin-8, ICAM-1 and VCAM-1 expression in hDPCs. Bromelain significantly decreased interleukin-1ß, interleukin-6, interleukin-8, ICAM-1, and VCAM-1 levels in hDPCs, which were stimulated by LPS. Bromelain treatment significantly reduced p65 phosphorylation in the cytoplasm and the nucleus. It also significantly decreased phosphorylation levels of extracellular signal-related kinases (ERK) and p38 mitogen-activated protein kinases (p38). Bromelain also promoted ALP activity and mineralized nodule formation. Conclusions: Bromelain inhibits the expression of inflammatory cytokines in LPS-stimulated hDPCs. The inhibitory effect of bromelain on inflammatory mediators is related to decreased NF-κB and the MAPK pathway. Therefore, bromelain might have the potential to be used for regenerative endodontics, including vital pulp therapy.

Characterization, Antimicrobial Effects, and Cytocompatibility of a Root Canal Sealer Produced by Pozzolan Reaction between Calcium Hydroxide and Silica.

This study aimed to evaluate a newly developed pozzolan-based bioceramic sealer (PZBS) regarding setting time, radiopacity, antibacterial effect, and cytocompatibility. The PZBS was manufactured by mixing calcium hydroxide and silica. The pozzolan reaction was verified by identification of calcium silicate hydrate (C-S-H) using X-ray diffraction analysis. The initial setting time and radiopacity were measured using the ISO 6876/2012 protocol in comparison with other commercially available calcium silicate (CS) sealers. The antibacterial effect of PZBS on biofilms cultured in the bovine root canal was evaluated by measurement of colony-forming units and volume of biofilms in comparison with other calcium hydroxide pastes. The morphological features of the biofilms were observed by scanning electron microscopy (SEM). The cytocompatibility of PZBS was assessed by the viability of bone marrow-derived mesenchymal stem cells and scratch wound healing rate in comparison with other CS sealers. The morphology of the cells cultured on the tested sealers was observed by SEM. The detection of the CS peak confirmed the formation of C-S-H. The initial setting time of PZBS was around 11 h, which was twice as long as the other tested sealers. The radiopacity of PZBS was 4.3 mm/Al, which satisfied the ISO criteria. The antibacterial effect and cytocompatibility of PZBS were comparable to those of the commercially available intracanal medicaments and CS endodontic sealers, respectively. The PZBS has the potential to be used for root canal obturation, and is expected to exert a favorable antibacterial effect.

Hard tissue formation after direct pulp capping with osteostatin and MTA in vivo.

OBJECTIVES: In recent in vitro study, it was reported that osteostatin (OST) has an odontogenic effect and synergistic effect with mineral trioxide aggregate (MTA) in human dental pulp cells. Therefore, the aim of this study was to evaluate whether OST has a synergistic effect with MTA on hard tissue formation in vivo. MATERIALS AND METHODS: Thirty-two maxillary molars of Spraque-Dawley rats were used in this study. An occlusal cavity was prepared and the exposed pulps were randomly divided into 3 groups: group 1 (control; ProRoot MTA), group 2 (OST 100 µM + ProRoot MTA), group 3 (OST 10 mM + ProRoot MTA). Exposed pulps were capped with each material and cavities were restored with resin modified glass ionomer. The animals were sacrificed after 4 weeks. All harvested teeth were scanned with micro-computed tomography (CT). The samples were prepared and hard tissue formation was evaluated histologically. For immunohistochemical analysis, the specimens were sectioned and incubated with primary antibodies against dentin sialoprotein (DSP). RESULTS: In the micro-CT analysis, it is revealed that OST with ProRoot MTA groups showed more mineralized bridge than the control (p < 0.05). In the H&E staining, it is showed that more quantity of the mineralized dentin bridge was formed in the OST with ProRoot MTA group compared to the control (p < 0.05). In all groups, DSP was expressed in newly formed reparative dentin area. CONCLUSIONS: OST can be a supplementary pulp capping material when used with MTA to make synergistic effect in hard tissue formation.

Growth Modeling for Quantitative, Spatially Resolved Geographic Atrophy Lesion Kinetics.

Purpose: To demonstrate the applicability of a growth modeling framework for quantifying spatial variations in geographic atrophy (GA) lesion kinetics. Methods: Thirty-eight eyes from 27 patients with GA secondary to age-related macular degeneration were imaged with a commercial swept source optical coherence tomography instrument at two visits separated by 1 year. Local GA growth rates were computed at 6-µm intervals along each lesion margin using a previously described growth model. Corresponding margin eccentricities, margin angles, and growth angles were also computed. The average GA growth rates conditioned on margin eccentricity, margin angle, growth angle, and fundus position were estimated via kernel regression. Results: A total of 88,356 GA margin points were analyzed. The average GA growth rates exhibited a hill-shaped dependency on eccentricity, being highest in the 0.5 mm to 1.6 mm range and lower on either side of that range. Average growth rates were also found to be higher for growth trajectories oriented away from (smaller growth angle), rather than toward (larger growth angle), the foveal center. The dependency of average growth rate on margin angle was less pronounced, although lesion segments in the superior and nasal aspects tended to grow faster. Conclusions: Our proposed growth modeling framework seems to be well-suited for generating accurate, spatially resolved GA growth rate atlases and should be confirmed on larger datasets. Translational Relevance: Our proposed growth modeling framework may enable more accurate measurements of spatial variations in GA growth rates.

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 a calcium hydroxide-based intracanal medicament containing N-2-methyl pyrrolidone as a vehicle against Enterococcus faecalis biofilm.

INTRODUCTION: This study investigated the effect of a calcium hydroxide (CH) paste (CleaniCal®) containing N-2-methyl pyrrolidone (NMP) as a vehicle on Enterococcus faecalis (E. faecalis) biofilms compared with other products containing saline (Calasept Plus™) or propylene glycol (PG) (Calcipex II®). METHODOLOGY: Standardized bovine root canal specimens were used. The antibacterial effects were measured by colony-forming unit counting. The thickness of bacterial microcolonies and exopolysaccharides was assessed using confocal laser scanning microscopy. Morphological features of the biofilms were observed using field-emission scanning electron microscopy (FE-SEM). Bovine tooth blocks covered with nail polish were immersed into the vehicles and dispelling was observed. The data were analyzed using one-way analysis of variance and Tukey tests (p<0.05). RESULTS: CleaniCal® showed the highest antibacterial activity, followed by Calcipex II® (p<0.05). Moreover, NMP showed a higher antibacterial effect compared with PG (p<0.05). The thickness of bacteria and EPS in the CleaniCal® group was significantly lower than that of other materials tested (p<0.05). FE-SEM images showed the specimens treated with Calasept Plus™ were covered with biofilms, whereas the specimens treated with other medicaments were not. Notably, the specimen treated with CleaniCal® was cleaner than the one treated with Calcipex II®. Furthermore, the nail polish on the bovine tooth block immersed in NMP was completely dispelled. CONCLUSIONS: CleaniCal® performed better than Calasept Plus™ and Calcipex II® in the removal efficacy of E. faecalis biofilms. The results suggest the effect might be due to the potent dissolving effect of NMP on organic substances.