Hydrogel Arrays and Choroidal Neovascularization Models for Evaluation of Angiogenic Activity of Vital Pulp Therapy Biomaterials

Physicochemical, mechanical and biological properties of nano-calcium silicate-based cements: a systematic review

This systematic review evaluated the effects of nano-sized cement particles on the properties of calcium silicate-based cements (CSCs). Using defined keywords, a literature search was conducted to identify studies that investigated properties of nano-calcium silicate-based cements (NCSCs). A total of 17 studies fulfilled the inclusion criteria. Results indicated that NCSC formulations have favourable physical (setting time, pH and solubility), mechanical (push out bond strength, compressive strength and indentation hardness) and biological (bone regeneration and foreign body reaction) properties compared with commonly used CSCs. However, the characterization and verification for the nano-particle size of NCSCs were deficient in some studies. Furthermore, the nanosizing was not limited to the cement particles and a number of additives were present. In conclusion, the evidence available for the properties of CSC particles in the nano-range is deficient-such properties could be a result of additives which may have enhanced the properties of the material.

Recent Progress on the Applications of Nanomaterials and Nano-Characterization Techniques in Endodontics: A Review

The impact of nano-based technologies in endodontics for the identification and treatment of various dental infections is showing fast progress. Studies show that nanoparticles could serve as useful agents with many beneficial results and continue to be promising in the field of endodontics. To ensure progress and improvements on novel nanomaterials in relation to their physicochemical and biological properties, nano-identification methods for the detection and evaluation of diseases need to be further highlighted. This study aims to review the current technological progress and recent research outcomes as well as possible prospective applications of nano-based technologies in endodontics. A comprehensive literature survey has been carried out on the utilizations of nanomaterials and nano-characterization techniques in endodontics. The current status and recent applications in endodontics are discussed with illustrative examples. The results have shown that the progress and improved accuracy of nano-identification techniques enabled a better characterization, evaluation and selection of appropriate treatment plans for endodontics-related diseases. The results have been inspiring for further clinical investigations. Nano-endodontics is still a developing field with a strong potential for revolutions of novel materials and techniques in the diagnosis and treatment of dental diseases. Further improvements in nanoparticles properties will pave the way for the development of many beneficial endodontic therapeutic agents. The future looks encouraging for sustainable products and testing methods for clinical endodontic applications.

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 Novel Polyurethane Expandable Root Canal Sealer

INTRODUCTION

Endodontic sealers play a vital role in the obturation of root canal space. The aim of this study was to evaluate the utility of a recently developed polyurethane expandable sealer (PES), along with its cytotoxicity and dimensional changes.

METHODS

L929 fibroblasts and an cell viability assay (MTS assay) were used to determine the cytotoxicity of dental sealers (AH Plus [Dentsply Maillefer, Ballaigues, Switzerland], Sure-Seal Root [Sure Dent Corporation, Gyeonggi-do, South Korea], and the PES) at 24, 48, 72, and 96 hours. An advanced choroidal neovascularization model was used to assess the effect of these sealers on angiogenesis. Thirty-six extracted single-rooted human teeth were prepared and randomly divided into 3 groups (n = 12). Obturation was performed with gutta-percha and a sealer using lateral compaction as follows: group 1, AH Plus; group 2, Sure-Seal; and group 3, PES. The average depth of sealer penetration into dentinal tubules was measured with a scanning electron microscope. Data were analyzed using 1-way analysis of variance and post hoc Tukey tests (level of significance, P < .05).

RESULTS

The values of MTS, choroidal neovascularization, and the penetration depth of PES were significantly higher than in other experimental groups (P < .05). The lowest values were noted in specimens of AH Plus, whereas the highest were detected in the PES group.

CONCLUSIONS

PES showed promising results in terms of biocompatibility and dentinal tubule adaptation and penetration.

Noninvasive temporal detection of early retinal vascular changes during diabetes

Diabetes associated complications, including diabetic retinopathy and loss of vision, are major health concerns. Detecting early retinal vascular changes during diabetes is not well documented, and only few studies have addressed this domain. The purpose of this study was to noninvasively evaluate temporal changes in retinal vasculature at very early stages of diabetes using fundus images from preclinical models of diabetes. Non-diabetic and Akita/+ male mice with different duration of diabetes were subjected to fundus imaging using a Micron III imaging system. The images were obtained from 4 weeks- (onset of diabetes), 8 weeks-, 16 weeks-, and 24 weeks-old male Akita/+ and non-diabetic mice. In total 104 fundus images were subjected to analysis for various feature extractions. A combination of Canny Edge Detector and Angiogenesis Analyzer plug-ins in ImageJ were utilized to quantify various retinal vascular changes in fundus images. Statistical analyses were conducted to determine significant differences in the various extracted features from fundus images of diabetic and non-diabetic animals. Our novel image analysis method led to extraction of over 20 features. These results indicated that some of these features were significantly changed with a short duration of diabetes, and others remained the same but changed after longer duration of diabetes. These patterns likely distinguish acute (protective) and chronic (damaging) associated changes with diabetes. We show that with a combination of various plugging one can extract over 20 features from retinal vasculature fundus images. These features change during diabetes, thus allowing the quantification of quality of retinal vascular architecture as biomarkers for disease progression. In addition, our method was able to identify unique differences among diabetic mice with different duration of diabetes. The ability to noninvasively detect temporal retinal vascular changes during diabetes could lead to identification of specific markers important in the development and progression of diabetes mediated-microvascular changes, evaluation of therapeutic interventions, and eventual reversal of these changes in order to stop or delay disease progression.

Moderately Acidic pH Promotes Angiogenesis: An In Vitro and In Vivo Study

INTRODUCTION

This study evaluated the effect of different pH values of 4.4, 5.4, 6.4, 7.4, 8.4, and 9.4 on angiogenesis.

METHODS

Endothelial cells were isolated from the mice molar teeth and placed in 42 Matrigel (Corning, NY)-coated wells, which were prepared and divided into 6 groups (n = 7). Synthetic tissue fluid was prepared and divided into 6 parts, and their pH values were adjusted to 4.4, 5.4, 6.4, 7.4, 8.4, and 9.4. A 2-mL volume from each group was diluted in the growth medium at a ratio of 1:3 and used for tubulogenesis assay. Forty-two 6-week-old mice in 6 groups (n = 7) were used for choroidal neovascularization (CNV). A 2-μL volume from each group or saline (control) was delivered by intravitreal injection on the day of laser application and 1 week later. Data on the number of nodes, the total length of the branches, and CNV areas (μm²) were determined using ImageJ software (National Institutes of Health, Bethesda, MD) and analyzed with 1-way analysis of variance and post hoc Tukey tests. The correlation was assessed between the tested variables.

RESULTS

The number of nodes decreased with changes in pH values as follows: 6.4 > 5.4 > 7.4 > 8.4 > 9.4 > 4.4. The total branch length decreased with pH value changes as follows: 6.4 > 4.4 > 6.4 > 7.4 > 8.4 > 9.4, and the CNV areas decreased with pH value changes as follows: 6.4 > 5.4 > 4.4 > 7.4 > 8.4 > 9.4.

CONCLUSIONS

Moderately acidic pH values (5.4 and 6.4) enhanced angiogenesis, whereas moderately alkaline pH values (8.4 and 9.4) suppressed angiogenesis.