Physical evaluation of a new pulp capping material developed from portland cement

Evaluating the Effect of Tideglusib-Loaded Bioactive Glass Nanoparticles as a Potential Dentine Regenerative Material

Dental pulp treatment is the least intrusive procedure currently available for preserving the vitality of the pulp. Several studies are underway to improve the bioactivity of pulp capping materials. Tideglusib isa potent anti-inflammatory, antioxidant, and a regenerative drug developed against Alzheimer’s disease and has been shown to be effective in the treatment of dental cavities. However, its bioactive properties encapsulated within the nanoparticles as a component of pulp capping material are largely unknown. In this study, tideglusib-loaded bioactive glass nanoparticles were synthesized (tideglusib-BgNPs) and mixed at various concentrations into the calcium silicate cement to testits physiomechanical and bioactivitiescompared with biodentine (control). The calcium silicate cement with 10wgt% tideglusib-BgNPs showed comparable physiomechanical properties to that of biodentine. Additionally, the assessment of cytotoxicity and bioactivity (cell proliferation, wound healing, and cell migration assays) showed increased bioactivity in terms of better wound healing, increased proliferation, and better migration of human dental pulp stem cells than biodentine. These findings suggest new opportunities to use tideglusib-BgNPs in pulp therapy.

Portland Cement: An Overview as a Root Repair Material

Portland cement (PC) is used in challenging endodontic situations in which preserving the health and functionality of pulp tissue is of considerable importance. PC forms the main component of mineral trioxide aggregate (MTA) and demonstrates similar desirable properties as an orthograde or retrograde filling material. PC is able to protect pulp against bacterial infiltration, induce reparative dentinogenesis, and form dentin bridge during the pulp healing process. The biocompatibility, bioactivity, and physical properties of PC have been investigated in vitro and in animal models, as well as in some limited clinical trials. This paper reviews Portland cement's structure and its characteristics and reaction in various environments and eventually accentuates the present concerns with this material. This bioactive endodontic cement has shown promising success rates compared to MTA; however, considerable modifications are required in order to improve its characteristics and expand its application scope as a root repair material. Hence, the extensive chemical modifications incorporated into PC composition to facilitate preparation and handling procedures are discussed. It is still important to further address the applicability, reliability, and cost-effectiveness of PC before transferring into day-to-day clinical practice.

The Effect of Calcium-Silicate Cements on Reparative Dentinogenesis Following Direct Pulp Capping on Animal Models

Dental pulp vitality is a desideratum for preserving the health and functionality of the tooth. In certain clinical situations that lead to pulp exposure, bioactive agents are used in direct pulp-capping procedures to stimulate the dentin-pulp complex and activate reparative dentinogenesis. Hydraulic calcium-silicate cements, derived from Portland cement, can induce the formation of a new dentin bridge at the interface between the biomaterial and the dental pulp. Odontoblasts are molecularly activated, and, if necessary, undifferentiated stem cells in the dental pulp can differentiate into odontoblasts. An extensive review of literature was conducted on MedLine/PubMed database to evaluate the histological outcomes of direct pulp capping with hydraulic calcium-silicate cements performed on animal models. Overall, irrespective of their physico-chemical properties and the molecular mechanisms involved in pulp healing, the effects of cements on tertiary dentin formation and pulp vitality preservation were positive. Histological examinations showed different degrees of dental pulp inflammatory response and complete/incomplete dentin bridge formation during the pulp healing process at different follow-up periods. Calcium silicate materials have the ability to induce reparative dentinogenesis when applied over exposed pulps, with different behaviors, as related to the animal model used, pulpal inflammatory responses, and quality of dentin bridges.

Biological evaluation of hesperidin for direct pulp capping in dogs' teeth

This study compared the biological effect of Hesperidin, Mineral Trioxide Aggregate (MTA)-Angelus and calcium hydroxide for direct pulp capping. A total of 126 dogs, teeth were divided according to the post-treatment evaluation period into three groups (42 teeth each), group I: 2 weeks, group II: 4 weeks and group III: 8 weeks. Each group was further subdivided according to the pulp capping material into three subgroups (14 teeth each), subgroup A (Hesperidin), subgroup B (MTA-Angelus) and subgroup C (Dycal). Both inflammatory response and dentine bridge formation were assessed by histopathology. All data were statistically analysed. Resolution of the inflammation was recorded by the time with a significant difference between subgroups   within the same group (P<.05). Hesperidin, MTA-Angelus and Dycal showed either mild or moderate inflammation at 2 weeks with significant differences between subgroups (P < .05). At 4 and 8 weeks, there were no significant differences between subgroups (P > .05). Absence of complete or partial calcified bridge with no odontoblastic layer was reported in all subgroups at 2 weeks while at 4 weeks, the majority of samples in Hesperidin and MTA subgroups showed amorphous calcified deposit. At 8 weeks, there was no significant difference (P > .05) between subgroups except that 78.5% and 92.9% of Hesperidin and MTA-Angelus samples, respectively, showed moderate dentine bridge. Also, 78.5% of Hesperidin and Dycal samples revealed moderately thick dentine bridge while 78.7% of MTA-Angelus showed a thin dentine bridge with a significant difference between them (P < .05). In conclusion, Hesperidin is a promising pulp capping material inducing mild inflammation and good dentine bridge formation.

Chemico-physical and mechanical evaluation of three calcium silicate-based pulp capping materials

Aim

This study compared biointeractivity (pH of soaking water and calcium ions), porosity, water sorption, solubility, compressive strength, lap shear strength, as well as the apatite forming ability of three calcium silicate-based capping materials: Mineral trioxide aggregate (MTA), Biodentine (BD) and Tech Biosealer capping (BS).

Methods

One hundred and five discs of the tested materials were prepared in compliance with the manufacturer's instructions. The materials' pastes were placed in Teflon molds and allowed to set before testing. The pH and Ca⁺² ions were measured by a potentiometric method. Porosity, water sorption, and solubility were calculated through the measurement of initial mass, mass, saturated mass and dry mass. Apatite forming ability was measured by an Environmental Scanning Electron Microscope that was connected to a secondary electron detector for energy dispersive X-ray analysis. Meanwhile compressive strength was measured by a computer controlled universal testing machine. Lap shear strength was measured by computer software on the testing machine. All data were statistically analyzed.

Results

The tested materials showed Ca ions release and alkalization, which decreased with soaking time. The BD exhibited a very high Ca release at both short (3 h) and long times (28 days). Significant high values of open and apparent porosities, water sorption, and solubility were measured for BS, which was followed by the MTA then BD (P < .05). The BD had significant higher compressive and lap shear bond strength than the MTA and BS (P < .05).

Conclusion

MTA, BD and BS are biointeractive bioactive materials that possess the ability to release ions and form calcium phosphate deposits. Unlike BD, BS is incapable of alternating MTA in pulp capping due to its high porosities, water sorption and solubility, as well as poor compressive and lap shear bond strength.

A comparative study of the physicochemical properties of hesperidin, MTA-Angelus and calcium hydroxide as pulp capping materials

Aim

This study compared the setting time, radiopacity, solubility and pH changes between Hisperidin cement, MTA-Angelus and Calcium hydroxide cements.

Methods

The study was conducted on 3 equal groups of samples of the evaluated capping materials including; Hisperidin (group I, N = 24), MTA-Angelus (group II, N = 24) and Dycal (group III, N = 24). According to the assessed property, these groups were further subdivided into three equal subgroups (8 samples each) including; subgroup A for assessment of the setting time, subgroup B for assessment of radiopacity and subgroup C for assessment of the solubility of the material and evaluation of pH. All recorded data were tabulated and statistically analyzed.

Results

The highest mean value of setting time was for the MTA-Angelus followed by Hesperidin and Calcium hydroxide with 72.83, 48.26 and 1.58 min, respectively. MTA-Angelus had the highest radiopacity value and followed by Calcium hydroxide then Hesperidin. Hesperidin showed the solubility in distilled water (≈45% mass loss) in relation to Calcium hydroxide (≈19% mass loss). On the other hand, MTA-Angelus showed 9% increase in weight. On contrast to MTA and Calcium hydroxide, Hesperidin showed decrease in pH value throughout the evaluation periods. Higher pH values in MTA-Angelus and Calcium hydroxide were reported in comparison with Hesperidin.

Conclusion

Despite its slight acidic nature, lower radiopacity and longer initial setting time, Hesperidin, as a natural product, is a promising pulp capping material. Further research on Hesperidin powder is recommended to improve its physicochemical properties and to assess its biological actions.

Evaluation of Properties of Mineral Trioxide Aggregate with Methyl Cellulose as Liquid

OBJECTIVES

Mineral trioxide aggregate (MTA) is extensively used in endodontics. However, MTA is difficult to handle because of its granular consistency, low mechanical properties and initial looseness. The objective of this study was to assess the compressive strength (CS), diametral tensile strength (DTS), and pH of set MTA using methyl cellulose as liquid.

MATERIALS AND METHODS

White ProRoot MTA was used as the control group; modified MTA cement was prepared by mixing Portland cement, bismuth oxide and calcium sulfate (75%, 20% and 5%, respectively) as the experiment group. Methyl cellulose was used as hydrating liquid and compared with distilled water. The data were analyzed by two-way ANOVA.

RESULTS

The pH values of modified MTA cement set using deionized water and methyl cellulose were slightly, but not significantly, different (P>0.05). The DTS and CS tests for modified MTA cement hydrated with methyl cellulose showed a significant difference at one day and one week (P<0.05).

CONCLUSIONS

The results suggest that using methyl cellulose as the hydrating liquid enhances some mechanical properties but does not compromise pH of white ProRoot MTA.