Evaluation of skeletal and dentoalveolar changes in class II division I pediatric patients receiving myofunctional appliance therapy: A preliminary study.

BACKGROUND/PURPOSE: The treatment effect of myofunctional appliance therapy has remained debated. The aim of this study was to evaluate the skeletal and dentoalveolar effects in class II division I pediatric patients receiving Education Fonctionnelle (EF) myofunctional appliance therapy. METHODS: Thirteen patients undergoing EF appliance treatment (9 boys and 4 girls；average 9.3years old) met the inclusion criteria and 13 untreated patients (9 boys and 4 girls；average 9.9 years old) served as controls. Initial and one-year follow-up lateral cephalometric measurement was used to assess skeletal and dentoalveolar changes. Gender ratio was analyzed using Chi-square test. Age and cephalometric measurement changes within and between the two groups were analyzed using Mann-Whitney U test and Wilcoxon signed rank test and Benjamini - Hochberg procedure. RESULTS: There were no significant differences in age, gender ratio, and initial cephalometric measurement data between the two groups. One-year follow-up skeletal findings revealed no significant differences between the two groups. Regarding the dentoalveolar changes, only the values of the upper incisor angle related parameters revealed significances between the two group (with adjusted p value). CONCLUSION: In this preliminary small sample size study, the EF group demonstrated significant upper incisor angle decrease, lower incisor angle increase, and lower incisor tip to mandibular plane distance decrease in comparison to the values measured in the control group. However, only the upper incisor angle changes were statistically significant after p-value adjustment. The skeletal effect of the EF appliance could not be verified in one-year follow-up of cephalometric data.

Substitutions of strontium in bioactive calcium silicate bone cements stimulate osteogenic differentiation in human mesenchymal stem cells.

Calcium silicate cements have been considered as alternative bone substitutes owing to its extraordinary bioactivity and osteogenicity. Unfortunately, the major disadvantage of the cements was the slow degradation rate which may limit the efficiency of bone regeneration. In this study, we proposed a facile method to synthesize degradable calcium silicate cements by incorporating strontium into the cements through solid-state sintering. The effects of Sr incorporation on physicochemical and biological properties of the cements were evaluated. Although, our findings revealed that the incorporation of strontium retarded the hardening reaction of the cements, the setting time of different cements (11-19 min) were in the acceptable range for clinical use. The presence of Sr in the CS cements would hampered the precipitation of calcium phosphate products on the surface after immersion in SBF, however, a layer of precipitated calcium phosphate products can be formed on the surface of the Sr-CS cement within 1 day immersion in SBF. More importantly, the degradation rate of the cements increased with increasing content of strontium, consequentially raised the levels of released strontium and silicon ions. The elevated dissolving products may contribute to the enhancement of the cytocompatibility, alkaline phosphatase activity, osteocalcin secretion, and mineralization of human Wharton's jelly mesenchymal stem cells. Together, it is concluded that the strontium-incorporated calcium silicate cement might be a promising bone substitute that could accelerate the regeneration of irregularly shaped bone defects.

Trigeminocardiac reflex during non-surgical root canal treatment of teeth with irreversible pulpitis.

BACKGROUND/PURPOSE: Trigeminocardiac reflex (TCR) is a unique clinical incident of acute change in hemodynamic balance, which may lead to hypotension, bradycardia, and even clinical crisis. Up to date, no study so far considers the impact of non-surgical root canal treatment (NSRCT) of irreversible pulpitis teeth under either local infiltration or block anesthesia on hemodynamic change possibly related to TCR. METHODS: This study enrolled 111 patients with 138 irreversible pulpitis teeth that were treated by two sessions of NSRCT. The first session involved mainly the removal of vital pulp tissue with the direct stimulation of the dental branches of the trigeminal nerve, and the second session included the root canal enlargement and debridement with minimal disturbance to the dental branches of the trigeminal nerve. Vital signs mainly the blood pressure were recorded during both NSRCT sessions. RESULTS: The incidences of NSRCT patients with MABP decrease ≧10%, ≧15%, or ≧20% were all significantly higher in the first NSRCT session than in the second NSRCT session (all the P-values < 0.001). In the first NSRCT session, the incidence of patients with MABP decrease ≧10% was significantly associated with tooth type. For both upper and lower teeth, the patients with premolars treated by NSRCR had significantly higher incidences of MABP decrease ≧10% than those with either anterior or molar teeth treated by NSRCR (all the P-values < 0.05). CONCLUSION: We conclude that vital pulp extirpation may lead to a substantial drop in patient's blood pressure possibly related to TCR.

The synergistic effects of Chinese herb and injectable calcium silicate/ß-tricalcium phosphate composite on an osteogenic accelerator in vitro.

This study investigates the physicochemical and biological effects of traditional Chinese medicines on the ß-tricalcium phosphate (ß-TCP)/calcium silicate (CS) composites of bone cells using human dental pulp cell. CS is an osteoconductive and bioactive material. For this research we have combined ß-TCP and CS and check its effectiveness, a series of ß-TCP/CS composites with different ratios of Xu Duan (XD) were prepared to make new bioactive and biodegradable biocomposites for bone repair. XD has been used in Traditional Chinese Medicine for hundreds of years as an antiosteoporosis, tonic and antiaging agent for the therapy of low back pain, traumatic hematoma, threatened abortion and bone fractures. Formation of bone-like apatite, the diametral tensile strength, and weight loss of composites were considered before and after immersion in simulated body fluid (SBF). In addition, we also examined the effects of XD released from ß-TCP/CS composites and in vitro human dental pulp cell (hDPCs) and studied its behavior. The results show the XD-contained paste did not give any demixing when the weight ratio of XD increased to 5-10 % due to the filter-pressing effect during extrusion through the syringe. After immersion in SBF, the microstructure image showed a dense bone-like apatite layer covered on the ß-TCP/CS/XD composites. In vitro cell experiments shows that the XD-rich composites promote human dental pulp cells (hDPCs) proliferation and differentiation. However, when the XD quantity in the composite is more than 5 %, the amount of cells and osteogenesis protein of hDPCs were stimulated by XD released from ß-TCP/CS composites. The combination of XD in degradation of ß-TCP and osteogenesis of CS gives strong reason to believe that these calcium-based composite cements may prove to be promising bone repair materials.

The influence of different root canal open access shapes on the use of rotary root canal enlargement.

Background/purpose: The success of root canal treatments is influenced by the shape of the access opening and the outcomes of root canal enlargement. The aim of this study was to evaluate the impact of various rotary instruments on the maintenance of the root canal's central alignment post shaping, considering a range of access cavity designs. Materials and methods: Using digital tooth simulation, 4 sets of 12 teeth underwent traditional (TradAC) or conservative (ConsAC) access cavity preparations. Root canals were enlarged with TruNatomy or ProTaper Ultimate rotary instruments. Canal transportation and centering ratio were separately measured. Statistical analysis was performed using JMP trial 17 software. Results: The analysis revealed no significant difference in buccal and lingual canal transportation among different rotary instruments or canal enlargement designs (P > 0.05). TradAC yielded higher centering ratios in MB and ML canals, while ConsAC excelled in the distal canal for the TruNatomy group. Conversely, in the ProTaper Ultimate group, ConsAC demonstrated higher ML canal ratios (P < 0.05). Conclusion: TruNatomy maintained superior canal centering with ConsAC, while ProTaper performed better with TradAC.

An in vitro evaluation of aligner force decay in artificial saliva.

Background/purpose: The present study aimed to compare the force decay of invisible aligners for maxillary anterior teeth with 0.1 mm (D1), 0.2 mm (D2), and 0.3 mm (D3) labial movement within a simulated oral environment over 7 days. Materials and methods: The prepared invisible aligners were immersed in saliva (S) and subjected to applied force (F) for 7 days. The aligners were set and placed on the maxillary right central incisor with 0.1 mm (D1), 0.2 mm (D2), and 0.3 mm (D3) labial movement. Thin-film pressure sensors were used to measure the aligner force changes. The data were collected and analyzed by statistical methods. Results: Significant differences were observed in the initial and first-day force between the D2 and D3 groups under simulated oral environment force (SF) (P < 0.05). There was a significant difference in force decay between Day 1 and Day 7 for all groups (P < 0.05). The SFD1 group showed a significant decrease in force on Day 5 (P < 0.05), while the SFD2 and SFD3 groups showed significant force decay on Day 4 (P < 0.05). The force decay ratio on Day 7 was higher in the SFD3 group than in the SFD1 and SFD2 groups, but no significant difference was observed. Conclusion: Larger labial movement of the aligners resulted in higher force decay under artificial saliva environments, and the force decay of invisible aligners was increased by immersion time in artificial saliva.

Clinical evaluation of 3D-printed zirconia crowns fabricated by selective laser melting (SLM) for posterior teeth restorations: Short-term pilot study.

Background/purpose: Zirconia crowns (ZrC) without veneering porcelain have become an effective alternative in clinical practice. Monolithic zirconia restorations fabricated by the dry milling method do not have acceptable clinical properties. This study evaluated the periodontal qualities of three-dimensional printed ZrC using the modified United States Public Health Service (USPHS) criteria. Materials and methods: A total of 15 patients who required dental crowns were recruited, and all 15 teeth were restored with digital 3D-printed ZrC. All crowns were assessed at the time of crown placement and 2, 6, and 24 weeks post-placement. Clinical parameters, including plaque index, gingival index, probing depth, crown marginal integrity, and attrition of the antagonist's teeth, were evaluated and recorded. Results: According to the Modified California Dental Association quality evaluation system, 100% of the crowns received satisfactory grades. Despite the significant increase in plaque index and gingival index at two weeks post-ZrC placement, there was no deterioration in probing depth. Moreover, there was discard usage of ZrC on the antagonist's teeth at 24 weeks posttreatment. Of the 15 crowns, one tooth had to be extracted due to a vertical root fracture. Overall, the digital 3D-printed crowns showed no adverse effects on periodontal tissues after 24 weeks of follow-up. Conclusion: The 3D-printed ZrC showed no periodontal problems. It can serve as an alternative for patients, particularly those with high esthetic expectations.

An in vitro comparison of the frictional forces between archwires and self-ligating brackets of passive and active types.

The aim of this study was to compare the static and kinetic frictional forces generated by various contemporary designs of self-ligating brackets (SLBs) and different wire alloys. In total, six different brackets (four passive type SLB, one active SLB, and one conventional bracket) were investigated using stainless steel, nickel-titanium, and titanium-molybdenum alloy archwires of several sizes. The friction forces were measured by sliding on a bracket-wire combination system in an EZ instron testing machine. A scanning electron microscope (SEM) was used to examine the wear effects of the wall surfaces of bracket slots. Energy-dispersive spectroscopy (EDS) was used to identify the elemental compositions of the bracket surfaces. The data were collected and statistically analysed using analysis of variance. The results of static and kinetic frictional forces were lower in passive type SLBs (P < 0.05), except in the Smart Clip bracket. The wire materials or wire dimensions in the present study showed similar friction forces with no statistical differences (P > 0.05). The wearing effects were not obviously found in bracket slots under SEM observation. Only conventional brackets and mini-Clippy SLB revealed nickel ions via EDS analysis. This study shows that passive SLBs are associated with lower static or kinetic friction forces than those of active SLBs or conventional brackets. Wear on the bracket slots was not observed in the present study.

The Effect of Probiotics Use on Salivary Cariogenic Bacteria in Orthodontic Patients with Various Caries Risk Status.

BACKGROUND: The purpose of this study was to evaluate the change in intraoral cariogenic bacteria density after probiotic use in patients with orthodontic treatment, and to compare the impact of probiotics in patients with various caries risk status. METHODS: Patients that planned to receive orthodontic treatment were recruited according to this study's inclusion/exclusion criteria. A probiotic prescription (Lactobacteria 3 mg, Glycobacteria 2 mg) was started one month after the initial orthodontic treatment. Saliva sampling and cultures using a CRT kit (caries risk test) were performed at three time points (T0, T1, T2). Mutans streptococci (MS) and Lactobacilli (LB) density were evaluated and scored using the interpretation chart in the CRT kit to evaluate the change in bacteria density at three time points, to define the high and low caries risk prior to orthodontic treatment, and to evaluate if there were differences in probiotics between the high and low caries risk groups. RESULTS: Thirty-three orthodontic patients were enrolled, twenty-two classified as high caries risk and eleven as low caries risk. After undergoing treatment for one month, the densities of MS and LB increased significantly (p = 0.011, p = 0.001); probiotics for one month decreased the density of MS and LB, but the differences were statistically nonsignificant (p = 0.109, p = 0.109). Patients classified as low risk of caries demonstrated an increase in MS and LB density one month after orthodontic treatment (p = 0.024, p = 0.001), probiotic use did not result in a significant reduction in bacteria density (p = 1000, p = 0.933). In patients with high caries risk, there were no statistically significant changes in MS count between the three time points (p = 0.127); a significant change in LB density occurred at T0-T1 (p = 0.011) only. CONCLUSIONS: Supplemental use of probiotic oral tablets during orthodontic treatment aimed at reducing cariogenic bacteria count in saliva did not achieve significant differences, regardless of patients' risk status for caries.

Comparison of friction force between corroded and noncorroded titanium nitride plating of metal brackets.

INTRODUCTION: Titanium nitride (TiN) plating is a method to prevent metal corrosion and can increase the surface smoothness. The purpose of this study was to evaluate the friction forces between the orthodontic bracket, with or without TiN plating, and stainless steel wire after it was corroded in fluoride-containing solution. METHODS: In total, 540 metal brackets were divided into a control group and a TiN-coated experimental group. The electrochemical corrosion was performed in artificial saliva with 1.23% acidulated phosphate fluoride (APF) as the electrolytes. Static and kinetic friction were measured by an EZ-test machine (Shimadazu, Tokyo, Japan) with a crosshead speed of 10 mm per minute over a 5-mm stretch of stainless steel archwire. The data were analyzed by using unpaired t test and analysis of variance (ANOVA). RESULTS: Both the control and TiN-coated groups' corrosion potential was higher with 1.23% APF solution than with artificial solution (P <0.05). In brackets without corrosion, both the static and kinetic friction force between the control and TiN-coated brackets groups showed a statistically significant difference (P <0.05). In brackets with corrosion, the control group showed no statistical difference on kinetic or static friction. The TiN-coated brackets showed a statistical difference (P <0.05) on kinetic and static friction in different solutions. CONCLUSION: TiN-coated metal brackets, with corrosion or without corrosion, cannot reduce the frictional force.

Effects of treatment with local anesthetics on RANKL expression in MG63 and PDL cells.

BACKGROUND/PURPOSE: Local anesthesia (LA) application is a routine dental work in clinic. The aim of present study was to evaluate the extent of biologic effects of LA on periodontal ligaments (PDL) or bone cells (MG63). MATERIALS AND METHODS: Local anesthetics (LAs) at different concentrations were added to PDL and MG 63 cells. The viability of the cells was analyzed using an MTT assay. The inflammatory markers, COX-2, IL-1, IL-6 and TNF-A, of PDL and MG63 cells treated with LAs were analyzed with a Western blot assay. The extract medium of the LA-treated PDL cells was added to the MG63 cells for subsequent culture and to examine the RANKL, ALP, and OPG expression. The data were statistically analyzed with p < 0.05 set as an indication of significance. RESULTS: The viability of the PDL and MG63 cells was less 50% at LAs concentrations above the 10 mM. At high LA concentrations, the PDL and MG63 cells treated with LAs became spherical in shape, or vesicles developed in the cytoplasm. The IL-1, IL-6, and TNF-A expression in the PDL groups showed no statistical differences between Septanest and Scandonest (p > 0.05). The RANKL expression in the MG63 cells increased as the Septanest and Scandonest concentrations were increased in the PDL extract medium (p < 0.05) after 48 h of culturing. CONCLUSION: The LAs with adrenaline increased inflammation in the PDL and MG63 cells. The LA-treated PDL extract medium increased the RANKL expression in the MG63 cells.

Bidirectional Differentiation of Human-Derived Stem Cells Induced by Biomimetic Calcium Silicate-Reinforced Gelatin Methacrylate Bioink for Odontogenic Regeneration.

Tooth loss or damage is a common problem affecting millions of people worldwide, and it results in significant impacts on one's quality of life. Dental regeneration with the support of stem cell-containing scaffolds has emerged as an alternative treatment strategy for such cases. With this concept in mind, we developed various concentrations of calcium silicate (CS) in a gelatin methacryloyl (GelMa) matrix and fabricated human dental pulp stem cells (hDPSCs)-laden scaffolds via the use of a bioprinting technology in order to determine their feasibility in promoting odontogenesis. The X-ray diffraction and Fourier transform-infrared spectroscopy showed that the incorporation of CS increased the number of covalent bonds in the GelMa hydrogels. In addition, rheological analyses were conducted for the different concentrations of hydrogels to evaluate their sol-gel transition temperature. It was shown that incorporation of CS improved the printability and printing quality of the scaffolds. The printed CS-containing scaffolds were able to release silicate (Si) ions, which subsequently significantly enhanced the activation of signaling-related markers such as ERK and significantly improved the expression of odontogenic-related markers such as alkaline phosphatase (ALP), dentin matrix protein-1 (DMP-1), and osteocalcin (OC). The calcium deposition assays were also significantly enhanced in the CS-containing scaffold. Our results demonstrated that CS/GelMa scaffolds were not only enhanced in terms of their physicochemical behaviors but the odontogenesis of the hDPSCs was also promoted as compared to GelMa scaffolds. These results demonstrated that CS/GelMa scaffolds can serve as cell-laden materials for future clinical applications and use in dentin regeneration.

Effects of different aligner materials and attachments on orthodontic behavior.

BACKGROUND/PURPOSE: The orthodontic aligner becomes popular worldwide in orthodontic therapy as an esthetic alternative to fixed labial braces. This study evaluated orthodontic tooth movement behavior using different aligner materials and attachment shapes for the movement of a single tooth. MATERIALS AND METHODS: First bicuspid extracted resin typodont models were printed with a 3D printer. Three type of attachments, an ellipsoid shape (thick and thin) and a bar, were designed to fit the canine crown surface. Three types of aligner materials, Polyethylene Terephthalate enhanced with glycol (BIOSTAR) Polyethylene Terephthalate (BenQ), and Thermoplastic polyurethanes (TPU) were used to fabricate different aligners. The typodonts with aligners were sunk in a water bath to simulate canine distal movement in vivo. The canine crown, root movement, and long axis angle changes in each step were calculated and recorded. The data were analysed using a oneway ANOVA statistical method. RESULTS: Comparing the three aligners, the changes the long axis of the canine showed that the BENQ group had a smaller change in the long axis angle. The BENQ group canine involved bodily movement, but the canine movement of the BIOSTAR and TPU group involved tipping. Comparing the three attachments, the bar type attachment had more canine crown tipping in the BIOSTAR and TPU groups. The thick and thin ellipsoid-shaped attachments showed no statistical differences in tooth movement. CONCLUSION: Attachment shape or size had little influence on the bodily movement of the tooth. A high modulus material may thus be suitable for clinical applications.

The Development of Light-Curable Calcium-Silicate-Containing Composites Used in Odontogenic Regeneration.

Pulp regeneration is one of the most successful areas in the field of tissue regeneration, despite its current limitations. The biocompatibility of endodontic biomaterials is essential in securing the oral microenvironment and supporting pulp tissue regeneration. Therefore, the objective of this study was to investigate the new light-curable calcium silicate (CS)-containing polyethylene glycol diacrylate (PEGDA) biocomposites' regulation of human dental pulp stem cells (hDPSCs) in odontogenic-related regeneration. The CS-containing PEGDA (0 to 30 wt%) biocomposites are applied to endodontics materials to promote their mechanical, bioactive, and biological properties. Firstly, X-ray diffraction and Fourier-transform infrared spectroscopy showed that the incorporation of CS increased the number of covalent bonds in the PEGDA. The diameter tension strength of the CS-containing PEGDA composite was significantly higher than that of normal PEGDA, and a different microstructure was detected on the surface. Samples were analyzed for their surface characteristics and Ca/Si ion-release profiles after soaking in simulated body fluid for different periods of time. The CS30 group presented better hDPSC adhesion and proliferation in comparison with CS0. Higher values of odontogenic-related biomarkers were found in hDPSCs on CS30. Altogether, these results prove the potential of light-curable CS-containing PEGDA composites as part of a 'point-of-care' strategy for application in odontogenesis-related regeneration.

Variations in surface characteristics and corrosion behaviour of metal brackets and wires in different electrolyte solutions.

The aim of this study was to assess the surface characteristics and to compare the corrosion potential of metal brackets and wires in environments containing different media. Four brands of metal brackets and two types of orthodontic wires [stainless steel and nickel-titanium (NiTi)] were investigated. An electrochemical assay was used to compare the corrosion potential (V) of the brackets and wires in different electrolyte media at 37°C. The test media were acidulated sodium fluoride (NaF) and pH 4 and pH 6 artificial saliva solutions. The data were analysed using analysis of variance with a predetermined significance level of α = 0.05. Scanning electron microscopy (SEM) was used to observe surface defects and corrosion. The results of the potentiodynamic curve showed that most brands of metal brackets were easily corroded in the NaF and pH 4 environments, while the NiTi and stainless steel wires were easily corroded in the pH 4 artificial saliva. SEM observations showed that defects or pitting corrosion occurred on the surfaces of the brackets and wires in all tested media.

Orthodontic adhesives induce human gingival fibroblast toxicity and inflammation.

OBJECTIVE: To test the null hypothesis that the resin base and the resin hybrid glass ionomer base adhesives do not cause inflammation after contacting primary human gingival fibroblasts in vitro. MATERIALS AND METHODS: The resin base and resin hybrid glass ionomer base adhesives were used to treat human gingival fibroblasts to evaluate the survival rate using MTT colorimetric assay to detect the level of cyclooxygenase-2 (COX-2) mRNA by reverse transcription polymerase chain reaction (RT-PCR) technique and COX-2 protein expression using Western blot analysis. The results were analyzed using one-way analysis of variance (ANOVA). Tests of differences of the treatments were analyzed using the Tukey test and a value of P < .05 was considered statistically significant. RESULTS: The paste and primer of the resin base adhesive and the liquid of glass ionomer adhesive showed decreasing survival rates after 24 hours of treatment (P < .05). All orthodontic adhesives induced COX-2 protein expression in human gingival fibroblasts. The exposure of quiescent human gingival fibroblasts to adhesives resulted in the induction of COX-2 mRNA expression. The investigations of the time-dependent COX-2 mRNA expression in adhesive-treated human gingival fibroblasts revealed different patterns. CONCLUSIONS: The hypothesis is rejected. For orthodontic patients with gingival inflammation, except for those with oral hygiene problems, the activation of COX-2 expression by orthodontic adhesive may be one of the potential mechanisms.

Biocompatibility of various formula root filling materials for primary teeth.

The aim of this study was to compare the effects of different materials used in primary root canal fillings on the cell viability of human osteosarcoma cell lines. The experimental group contained six different types of root canal filling materials, including zinc oxide (ZnO) + eugenol + formocresol (FC), Ca(OH)(2) + FC, Ca(OH)(2) + Iodoform, Ca(OH)(2) + Iodoform + camphorated parachlorophenol (CPC), Ca(OH)(2) + CPC, and Vitapex. Cell viability tests were performed using tetrazolium bromide colorimetric (MTT) assay on human osteosacorma cell lines (U2OS). The results were analyzed using one-way analysis of variance (ANOVA) and Student-Newman-Keul's test with p < 0.05 showed statistical differences. The ZnO + eugenol + FC group and Ca(OH)(2) + FC group showed the lowest survival rates (p < 0.05). The Ca(OH)(2) + Iodoform + CPC group and Ca(OH)(2) + CPC group showed significantly lower survival rates at concentrations above 6 microL/mL (p < 0.05). The Ca(OH)(2) + Iodoform group and Vitapex group showed the highest survival rates (p < 0.05). We concluded that the use of calcium hydroxide with iodoform as a root filling base material is a better option than other medications.

Cytotoxicity of orthodontic wire corroded in fluoride solution in vitro.

OBJECTIVE: To investigate the toxicity of fluoride corrosion extracts of stainless steel (SS) and nickel-titanium (NiTi) wires on a human osteosarcoma cell line (U2OS). MATERIALS AND METHODS: The SS and NiTi wires were corroded by an electrochemical method with the application of three kinds of electrolytes: 0.2% pH 3.5 acidulated phosphate fluoride (NaF) in artificial saliva, and pH 4 and pH 6.75 artificial saliva solutions. The extracts were analyzed for nickel, chromium, and titanium ions by the atomic absorption method. The extracts were diluted with medium to different concentrations (1, 0.1, and 0.01 microL/mL). The cell survival rate was determined by the ability of test cells to cleave the tetrazolium salt to form a formazan dye. RESULTS: The results were compared using one-way analysis of variance. Differences between the treatment means were analyzed using a Student-Newman-Keuls (SNK) test and were considered significant at P < .05. The release of ionic nickel was different in different extract groups (P < .05). The SS and NiTi wires in the 0.2% pH 3.5 NaF artificial saliva group caused a dose-dependent decrease in the survival rate (P < .05). Survival rates of cells in the groups exposed to extracts of SS and NiTi wires in pH 4 and pH 6.75 artificial saliva solutions showed no statistical differences (P >.05). CONCLUSIONS: Orthodontic wires in acidulated fluoride saliva solution can cause U2OS cell toxicity.

Mesoporous Calcium Silicate Nanoparticles with Drug Delivery and Odontogenesis Properties.

INTRODUCTION: Calcium silicate (CS) -based materials play an important role in the development of endodontic materials that induce bone/cementum tissue regeneration and inhibit bacterial viability. The aim of this study was to prepare novel mesoporous CS (MesoCS) nanoparticles that have osteogenic, drug delivery, and antibacterial characteristics for endodontic materials and also have an excellent ability to develop apatite mineralization. METHODS: The MesoCS nanoparticles were prepared using sol-gel methods. In addition, the mesoporous structure, specific surface area, pore volume, and morphology of the MesoCS nanoparticles were analyzed. The apatite mineralization ability, in vitro odontogenic differentiation, drug delivery, and antibacterial properties of the MesoCS nanoparticles were further investigated. RESULTS: The results indicate that the 200-nm-sized MesoCS nanoparticles synthesized using a facile template method exhibited a high specific surface area and pore volume with internal mesopores (average pore size = 3.05 nm). Furthermore, the MesoCS nanoparticles can be used as drug carriers to maintain sustained release of gentamicin and fibroblast growth factor-2 (FGF-2). The MesoCS-loaded FGF-2 might stimulate more odontogenic-related protein than CS because of the FGF-2 release. CONCLUSIONS: Based on this work, it can be inferred that MesoCS nanoparticles are potentially useful endodontic materials for biocompatible and osteogenic dental pulp tissue regenerative materials.