Comparison of Four Dental Pulp-Capping Agents by Cone-Beam Computed Tomography and Histological Techniques—A Split-Mouth Design Ex Vivo Study

Effect of four direct pulp capping agents on human dental pulp tissue

Direct pulp capping (DPC) is a vital pulp therapy, wherein accidental or carious pulp exposures can be capped with various materials to induce reparative dentine formation. One of the major factors that determine the success of direct pulp capping procedures is the material used. Therefore, it is of interest to evaluate and compare the efficacy of a new material, Tristrontium aluminate in comparison with the widely used materials such as ProRoot MTA, Biodentine & TheraCal LC. Hence, 40 premolars scheduled for extraction for orthodontic treatment, were equally divided into 4 groups and iatrogenic DPC was done using one of the study materials. The premolars were then extracted after 90 days & assessed for the formation of Dentine Bridge and pulpal response elicited by the materials using CBCT and histopathological analysis. All the materials tested in the study were successful in inducing dentine bridge formation & maintaining pulp vitality. Thus, the novelty of Tristrontium aluminate for potential applications in future is eminent.

An animal study on the effectiveness of platelet-rich plasma as a direct pulp capping agent

Direct pulp capping (DPC) is a conservative approach for preserving tooth vitality without requiring more invasive procedures by enhancing pulp healing and mineralized tissue barrier formation. We investigated the effectiveness of Platelet Rich Plasma (PRP) vs. Mineral Trioxide Aggregate (MTA) as a DPC agent. Forty-two teeth from three mongrel dogs were divided into two equal groups. After three months, the animals were sacrificed to evaluate teeth radiographically using cone-beam computerized tomography, histopathologically, and real-time PCR for dentin sialophosphoprotein (DSPP), matrix extracellular phosphoglycoprotein (MEPE), and nestin (NES) mRNA expression. Radiographically, hard tissue formation was evident in both groups without significant differences (p = 0.440). Histopathologic findings confirmed the dentin bridge formation in both groups; however, such mineralized tissues were homogenous without cellular inclusions in the PRP group, while was osteodentin type in the MTA group. There was no significant difference in dentin bridge thickness between the PRP-capped and MTA-capped teeth (p = 0.732). The PRP group had significantly higher DSPP, MEPE, and NES mRNA gene expression than the MTA group (p < 0.05). In conclusion, PRP enables mineralized tissue formation following DPC similar to MTA, and could generate better cellular dentinogenic responses and restore dentin with homogenous architecture than MTA, making PRP a promising alternative DPC agent.

Nano eggshell-based slurry as a direct pulp-capping material: In vitro characterization and histopathological assessment in an experimental animal model

AIM

Pulp vitality is essential for tooth integrity. Following pulp exposure, choosing a suitable pulp-capping material is crucial to maintain pulp vitality. However, the reparative dentine bridge created by calcium hydroxide (Ca(OH)2 ) is generally porous and incomplete. The aim of the current study is to assess the in vitro and in vivo bioactivities of nano eggshell-based slurry (NES), using NES as a direct pulp-capping material, compared with Ca(OH)2 in rabbit animal model.

METHODOLOGY

Nano eggshell powder (NE) was characterized for particle morphology, chemical composition and ion release. In vitro bioactivity was tested by immersion in simulated body fluid (SBF) for 7 days. For histopathological evaluation, 36 adult New Zealand rabbits (72 pulp exposures) were divided into nine groups (n = 8) according to the pulp-capping material (NES, Ca(OH)2 and no capping as negative control group) and the animals were sacrificed after 7, 14 or 28 days. The pulps of the two lower central incisors were exposed and then directly capped by Ca(OH)2 or NES or left untreated. The cavities were then sealed with glass ionomer cement. Teeth were collected for histopathological evaluation using an optical microscope. Pulp haemorrhage, inflammation, fibrosis and calcific bridge formation were assessed. Results were statistically analysed using anova and Tukey's tests.

RESULTS

Nano eggshell particles were spherical with a 20 nm diameter and were composed mainly of calcite. Statistical analysis showed that there was a significant increase in the release of all investigated ions between days 1 and 28, except for copper. NES group showed a significantly higher release of all elements as compared to Ca(OH)2 . Environmental scanning electron microscope micrographs of NES incubated for 7 days in SBF showed the formation of HAp with a Ca/P ratio (1.686). For histopathological evaluation, the difference between groups was statistically significant. At day 28, 75% of the pulps of the Ca(OH)2 group showed mild calcific bridge in comparison with 100% moderate calcific bridge in the NES group. The NES group showed significantly less inflammation at days 7 and 28, and higher fibrosis at day 7 compared with Ca(OH)2 .

CONCLUSIONS

Nano eggshell-based slurry represents a promising novel direct pulp-capping material with favourable pulp tissue response.

Tideglusib-incorporated nanofibrous scaffolds potently induce odontogenic differentiation

Pulp-Dentin regeneration is a key aspect of maintain tooth vitality and enabling good oral-systemic health. This study aimed to investigate a nanofibrous scaffold loaded with a small molecule i.e. Tideglusib to promote odontogenic differentiation. Tideglusib (GSK-3β inhibitor) interaction with GSK-3β was determined using molecular docking and stabilization of β-catenin was examined by confocal microscopy. 3D nanofibrous scaffolds were fabricated through electrospinning and their physicochemical characterizations were performed. Scaffolds were seeded with mesenchymal stem cells or pre-odontoblast cells to determine the cells proliferation and odontogenic differentiation. Our results showed that Tideglusib (TG) binds with GSK-3β at Cys199 residue. Stabilization and nuclear translocation of β-catenin was increased in the odontoblast cells treated with TG. SEM analysis revealed that nanofibers exhibited controlled architectural features that effectively mimicked the natural ECM. UV-Vis spectroscopy demonstrated that TG was incorporated successfully and released in a controlled manner. Both kinds of biomimetic nanofibrous matrices (PCLF-TG100, PCLF-TG1000) significantly stimulated cells proliferation. Furthermore, these scaffolds significantly induced dentinogenic markers (ALP, and DSPP) expression and biomineralization. In contrast to current pulp capping material driving dentin repair, the sophisticated, polymeric scaffold systems with soluble and insoluble spatiotemporal cues described here can direct stem cell differentiation and dentin regeneration. Hence, bioactive small molecule-incorporated nanofibrous scaffold suggests an innovative clinical tool for dentin tissue engineering.

The Influence of New Bioactive Materials on Pulp–Dentin Complex Regeneration in the Assessment of Cone Bone Computed Tomography (CBCT) and Computed Micro-Tomography (Micro-CT) from a Present and Future Perspective—A Systematic Review

The present paper is the first article providing a systematic literature review on the visualization of tertiary dentin influenced by modern bioactive materials in CBCT and micro-CT. Six database searches of studies on tertiary dentin visualization using CBCT produced 622 records in total, and the search of the studies on tertiary dentin using micro-CT produced 502 records in total. The results were thoroughly selected considering the inclusion criteria, and five research papers using CBCT and nine research papers using micro-CT for visualization of tertiary dentin were eventually qualified for the analysis. All the non-randomized and randomized studies presented good and high levels of quality evidence, respectively. Among the bioactive materials used, the most frequently analysed were: MTA, Biodentine dentin matrix hydrogel, Pro Root MTA, and EndoSequence root repair material. The highest thickness of the tertiary dentin was achieved after the use of MTA material in both imaging techniques. The remaining parameters had different results, taking into account the CBCT and micro-CT analysis. The possibilities of the qualitative and quantitative assessment of the particular parameters of tertiary dentin using CBCT and micro-CT techniques were presented and analysed. CBCT and micro-CT analyses can be useful in the assessment of tertiary dentin formed beneath the bioactive material applied during vital pulp treatment. The research argues that the presented results differ depending on the material applied to the pulp, the study duration (4–6 weeks), difference in teeth, species (rats, human), as well as the applied technique and differences in computer software used for the analysis.

An Update on Nickel-Titanium Rotary Instruments in Endodontics: Mechanical Characteristics, Testing and Future Perspective-An Overview

Since the introduction of Nickel-Titanium alloy as the material of choice for the manufacturing of endodontic rotary instruments, the success rate of the root canal therapies has been significantly increased. This success mainly arises from the properties of the Nickel-Titanium alloy: the biocompatibility, the superelasticity and the shape memory effect. Those characteristics have led to a reduction in time of endodontic treatments, a simplification of instrumentation procedures and an increase of predictability and effectiveness of endodontic treatments. Nevertheless, the intracanal separation of Nickel-Titanium rotary instruments is still a major concern of endodontists, with a consequent possible reduction in the outcome rate. As thoroughly demonstrated, the two main causes of intracanal separation of endodontic instruments are the cyclic fatigue and the torsional loads. As results, in order to reduce the percentage of intracanal separation research and manufacturers have been focused on the parameters that directly or indirectly influence mechanical properties of endodontic rotary instruments. This review describes the current state of the art regarding the Nickel-Titanium alloy in endodontics, the mechanical behavior of endodontic rotary instruments and the relative stresses acting on them during intracanal instrumentation, highlighting the limitation of the current literature.

Histological Aspects Regarding Dental Pulp of Diabetic Patients

Background: The possible histological changes in dental pulp in teeth of diabetic patients are important to be understood, as the clinician will consider the best treatment choice for those teeth, especially if they are affected by decay. The aim of this paper is to assess if there are effects of diabetes-associated hyperglycemia on the nervous and vascular system of the dental pulp. Methods: Twenty-three dental pulp specimens of patients aged 36–70 years old were analyzed. All patients had been diagnosed with type 2 diabetes for at least 5 years. Results: Most of the patients had poorly controlled hyperglycemia, deep caries, but no clinical signs of pulpitis. The histological aspects of pulp specimens included frequently seen inflammatory infiltrate, degeneration of the nerves, thickened blood vessel walls, pulp sclerosis and frequent pulp calcifications, and even small necrotic areas. Conclusion: The analyzed dental pulp specimens of carious teeth of type 2 diabetic patients show fibrotic transformation of the dental pulp, with the presence of calcifications, arteriosclerosis and inflammatory infiltrate. In this situation, the attitude of the dentist in pulp vitality preservation in the case of carious teeth of diabetic patients should be limited.

Optimization of X-ray Investigations in Dentistry Using Optical Coherence Tomography

The most common imaging technique for dental diagnoses and treatment monitoring is X-ray imaging, which evolved from the first intraoral radiographs to high-quality three-dimensional (3D) Cone Beam Computed Tomography (CBCT). Other imaging techniques have shown potential, such as Optical Coherence Tomography (OCT). We have recently reported on the boundaries of these two types of techniques, regarding. the dental fields where each one is more appropriate or where they should be both used. The aim of the present study is to explore the unique capabilities of the OCT technique to optimize X-ray units imaging (i.e., in terms of image resolution, radiation dose, or contrast). Two types of commercially available and widely used X-ray units are considered. To adjust their parameters, a protocol is developed to employ OCT images of dental conditions that are documented on high (i.e., less than 10 μm) resolution OCT images (both B-scans/cross sections and 3D reconstructions) but are hardly identified on the 200 to 75 μm resolution panoramic or CBCT radiographs. The optimized calibration of the X-ray unit includes choosing appropriate values for the anode voltage and current intensity of the X-ray tube, as well as the patient’s positioning, in order to reach the highest possible X-rays resolution at a radiation dose that is safe for the patient. The optimization protocol is developed in vitro on OCT images of extracted teeth and is further applied in vivo for each type of dental investigation. Optimized radiographic results are compared with un-optimized previously performed radiographs. Also, we show that OCT can permit a rigorous comparison between two (types of) X-ray units. In conclusion, high-quality dental images are possible using low radiation doses if an optimized protocol, developed using OCT, is applied for each type of dental investigation. Also, there are situations when the X-ray technology has drawbacks for dental diagnosis or treatment assessment. In such situations, OCT proves capable to provide qualitative images.