The development of a dental light curable PRFe-loaded hydrogel as a potential scaffold for pulp-dentine complex regeneration: An in vitro study.

AIM: The study aimed to develop a bicomponent bioactive hydrogel formed in situ and enriched with an extract of platelet-rich fibrin (PRFe) and to assess its potential for use in pulp-dentine complex tissue engineering via cell homing. METHODOLOGY: A bicomponent hydrogel based on photo-activated naturally derived polymers, methacrylated chitosan (ChitMA) and methacrylated collagen (ColMA), plus PRFe was fabricated. The optimized formulation of PRFe-loaded bicomponent hydrogel was determined by analysing the mechanical strength, swelling ratio and cell viability simultaneously. The physical, mechanical, rheological and morphological properties of the optimal hydrogel with and without PRFe were determined. Additionally, MTT, phalloidin/DAPI and live/dead assays were carried out to compare the viability, cytoskeletal morphology and migration ability of stem cells from the apical papilla (SCAP) within the developed hydrogels with and without PRFe, respectively. To further investigate the effect of PRFe on the differentiation of encapsulated SCAP, alizarin red S staining, RT-PCR analysis and immunohistochemical detection were performed. Statistical significance was established at p < .05. RESULTS: The optimized formulation of PRFe-loaded bicomponent hydrogel can be rapidly photocrosslinked using available dental light curing units. Compared to bicomponent hydrogels without PRFe, the PRFe-loaded hydrogel exhibited greater viscoelasticity and higher cytocompatibility to SCAP. Moreover, it promoted cell proliferation and migration in vitro. It also supported the odontogenic differentiation of SCAP as evidenced by its promotion of biomineralization and upregulating the gene expression for ALP, COL I, DSPP and DMP1 as well as facilitated angiogenesis by enhancing VEGFA gene expression. CONCLUSIONS: The new PRFe-loaded ChitMA/ColMA hydrogel developed within this study fulfils the criteria of injectability, cytocompatibility, chemoattractivity and bioactivity to promote odontogenic differentiation, which are fundamental requirements for scaffolds used in pulp-dentine complex regeneration via cell-homing approaches.

Microstructure and color stability of calcium silicate-based dental materials exposed to blood or platelet-rich fibrin.

OBJECTIVES: To investigate the effects of blood and platelet-rich fibrin (PRF), commonly used scaffolds in regenerative endodontic treatment (RET), on the hydration, microstructure, and color stability of three hydraulic calcium silicate cements (HCSCs), OrthoMTA, RetroMTA, and TotalFill-BC-RRM. MATERIALS AND METHODS: The HCSCs were prepared and placed into polyethylene molds and transferred to Eppendorf tubes containing PRF, blood, or PBS and then incubated for 1 week or 1 month. The microstructure and hydration of the cements were studied by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The chromatic alteration of materials was also measured using a spectrophotometer. The data for color stability were analyzed using 2-way analysis of variance and Tukey post hoc tests. RESULTS: There was no significant difference between the color stability of cements exposed to PBS (p > 0.05). The chromatic alteration of cements exposed to blood was significantly greater than those exposed to PRF and PBS (p < 0.001). In the presence of blood and PRF, the color change of OrthoMTA was significantly greater than that of RetroMTA and TotalFill (p < 0.05), with no significant difference between RetroMTA and TotalFill (p > 0.05). XRD analysis of all cements revealed a calcium hydroxide peak after 1-week and 1-month exposure to the media; however, OrthoMTA and TotalFill exposed to blood and PRF for 1 month showed weaker calcium hydroxide peaks. SEM images revealed cements exposed to PBS had a different surface microstructure compared to those exposed to blood and PRF. Furthermore, the surface microstructure of HCSCs was influenced by the type of cement radiopacifier (bismuth oxide or zirconium oxide). EDS analysis of the elemental composition in all groups displayed peaks of Ca, O, C, Si, P, and Al. CONCLUSIONS: Color stability, hydration behavior, and microstructure of HCSCs were affected by exposure to PRF and blood and the type of cement radiopacifier. CLINICAL RELEVANCE: As some important physicochemical properties of HCSCs could be influenced by the environmental conditions and the type of radiopacifier, alternatives to blood clot and HCSCs containing substitutes for bismuth oxide might be more suitable in RETs.

Advances in scaffolds used for pulp-dentine complex tissue engineering: A narrative review.

BACKGROUND: Pulp-dentine complex regeneration via tissue engineering is a developing treatment modality that aims to replace necrotic pulps with newly formed healthy tissue inside the root canal. Designing and fabricating an appropriate scaffold is a crucial step in such a treatment. OBJECTIVES: The present study aimed to review recent advances in the design and fabrication of scaffolds for de novo regeneration of pulp-dentine complexes via tissue engineering approaches. METHODS: A literature search was conducted using PubMed, Europe PMC, Scopus and Google Scholar databases. To highlight bioengineering techniques for de novo regeneration of pulp-dentine complexes, both in vitro and in vivo studies were included, and clinical studies were excluded. RESULTS: In the present review, four main classes of scaffolds used to engineer pulp-dentine complexes, including bioceramic-based scaffolds, synthetic polymer-based scaffolds, natural polymer-based scaffolds and composite scaffolds, are covered. Additionally, recent advances in the design, fabrication and application of such scaffolds are analysed along with their advantages and limitations. Finally, the importance of vascular network establishment in the success of pulp-dentine complex regeneration and strategies used to create scaffolds to address this challenge are discussed. DISCUSSION: In the tissue engineering platform, scaffolds provide structural support for cells to adhere and proliferate and also regulate cell differentiation and metabolism. Up to now, considerable progress has been achieved in the field of pulp-dentine complex tissue engineering, and a spectrum of scaffolds ranging from bioceramic-based to naturally derived scaffolds has been fabricated. However, in designing a suitable scaffold for engineering pulp-dentine complexes, a variety of characteristic parameters related to biological, structural, physical and chemical features should be considered. CONCLUSION: The variety of biomaterials and fabrication techniques provides a great opportunity to address some of the requirements for scaffolds in regenerative endodontics. However, more studies are required to develop an ideal scaffold for use in a clinical setting.

Crystalline phases involved in the hydration of calcium silicate-based cements: Semi-quantitative Rietveld X-ray diffraction analysis.

Chemical comparisons of powder and hydrated forms of calcium silicate cements (CSCs) and calculation of alterations in tricalcium silicate (Ca3 SiO5 ) calcium hydroxide (Ca(OH)2 ) are essential for understanding their hydration processes. This study aimed to evaluate and compare these changes in ProRoot MTA, Biodentine and CEM cement. Powder and hydrated forms of tooth coloured ProRoot MTA, Biodentine and CEM cement were subjected to X-ray diffraction (XRD) analysis with Rietveld refinement to semi-quantitatively identify and quantify the main phases involved in their hydration process. Data were reported descriptively. Reduction in Ca3 SiO5 and formation of Ca(OH)2 were seen after the hydration of ProRoot MTA and Biodentine; however, in the case of CEM cement, no reduction of Ca3 SiO5 and no formation of Ca(OH)2 were detected. The highest percentages of amorphous phases were seen in Biodentine samples. Ettringite was detected in the hydrated forms of ProRoot MTA and CEM cement but not in Biodentine.

Anesthetic efficacy of mental/incisive nerve block compared to inferior alveolar nerve block using 4% articaine in mandibular premolars with symptomatic irreversible pulpitis: a randomized clinical trial.

OBJECTIVES: The aim of this study was to compare the onset, success rate, injection pain, and post-injection pain of mental/incisive nerve block (MINB) with that of inferior alveolar nerve block (IANB) using 4% articaine in mandibular premolars with symptomatic irreversible pulpitis. The accuracy of electrical pulp test (EPT) in determining pulpal anesthesia was also examined. MATERIALS AND METHODS: The study was designed as a randomized clinical trial with two study arms-MINB and IANB. Injections were performed using a standardized technique. Root canal treatment was initiated 10 min after the injection. Success was defined as no pain or mild pain during access cavity preparation and instrumentation. Injection pain and post-injection pain (up to 7 days) were recorded. All pain ratings were done using Heft-Parker Visual Analog Scale (HP VAS). RESULTS: Sixty-four patients were enrolled. The success rate of MINB (93.8%) was higher than IANB (81.2%) but the difference was not significant (p > 0.05). The onset of anesthesia with MINB was significantly quicker, and injection pain was significantly less (p < 0.05), but post-injection pain was significantly higher during the first 4 days (p < 0.001). The accuracy of EPT in determining pulpal anesthesia was 96.88%. CONCLUSIONS: MINB and IANB with 4% articaine had similar efficacy in anesthetizing mandibular premolars with irreversible pulpitis. Post-injection pain with MINB was higher than with IANB. CLINICAL RELEVANCE: MINB and IANB with 4% articaine can be used interchangeably to anesthetize mandibular premolars with irreversible pulpitis.

Bonding to caries affected dentine.

OBJECTIVES: Dentine replacement materials are often placed over caries affected dentine (CAD). The aim of this study was to compare the bonding characteristics and interactions of selected hydraulic calcium silicate-based dentine replacement materials to CAD and sound dentine. METHODS: Three hydraulic calcium silicate-based dentine replacement materials were assessed: Retro MTA, Biodentine and Theracal LC. Material characterization was done by scanning electron microscopy and X-ray diffraction analyses. Blocks of sound and CAD were prepared and standardized by Vickers microhardness testing. Half of the affected and sound dentine blocks were pretreated with 5.25% NaOCl prior to material placement. The materials were stored either for 1 week or 24 weeks in 37°C in fully saturated conditions. Shear bond strength was assessed at both time periods. Radiopacity of the interfacial dentine was also evaluated to assess the remineralization potential of the dentine replacement materials. RESULTS: The reaction of Theracal was slower than that of the water-based materials. The bond strengths of different materials did not differ after 1 week (P>0.05). The bond strength of Biodentine and Retro MTA increased over time but no change was observed for Theracal. NaOCl pre-treatment deteriorated the bond strength to sound dentine but improvement was observed in affected dentine. Radiopacity changes were observed after 24 weeks. SIGNIFICANCE: Biodentine and Retro MTA showed better bonding to CAD. Pretreatment with NaOCl improved the bond strength of dentine replacement materials to CAD.

Effect of blood contamination on the compressive strength of three calcium silicate-based cements.

The aim of this study was to investigate the effect of human blood exposure on the compressive strength of various calcium silicate-based cements. Two hundred and eighty-eight customised cylindrical moulds were randomly divided into three groups according to material used: ProRoot MTA, Biodentine or CEM cement (n = 96). Each group was divided into two subgroups according to exposure conditions: PBS or blood. Then, the compressive strength of the specimens was measured after 6 h, 24 h, 72 h and 7 days. The compressive strength of CEM cement could not be measured after 6 and 24  h regardless of the exposure conditions nor could the compressive strength of 6 h blood-exposed ProRoot MTA. The compressive strength of blood-exposed ProRoot MTA was only significantly lower after 6 h, but no difference was seen at other time intervals. Blood exposed did adversely affected the compressive strength of Biodentine. The compressive strength of all groups significantly increased over time (P < 0.005).

Evaluation and Comparison of Occurrence of Tooth Discoloration after the Application of Various Calcium Silicate-based Cements: An Ex Vivo Study.

INTRODUCTION: Biodentine (Septodont, Saint Maur des Fossés, France), OrthoMTA (BioMTA, Seoul, Korea), and EndoSequence Root Repair Material (ERRM; Brasseler, Savannah, GA) have been developed to overcome the shortcomings of mineral trioxide aggregate (MTA). The purpose of this study was to compare tooth discoloration after the application of ProRoot MTA (Dentsply Tulsa Dental Products, Tulsa, OK) and 3 recently introduced calcium silicate-based cements in the presence and absence of blood. METHODS: In total, 104 human anterior teeth were prepared; 96 were randomly divided into 2 groups (blood and saline contamination). Each group was subdivided into 4 experimental subgroups (n = 12) of ProRoot MTA, Biodentine, OrthoMTA, and ERRM that were used to fill the pulp chambers. The remaining 8 teeth served as the saline and blood groups. Color analysis of tooth crowns was performed using a spectroradiometer before the application of materials and at 24 hours, 1 month, and 6 months after application. Repeated measures analysis of variance was used to evaluate the effects of blood, material, and time on color change (ΔE*). RESULTS: Tooth color change in all experimental groups increased over time (P < .05). Blood contamination significantly increased ΔE* (P < .05), but no significant difference occurred between the 4 groups in this respect in the presence of blood. However, in the absence of blood, the ΔE* of Biodentine and ERRM was significantly less than that of OrthoMTA (P < .05). CONCLUSIONS: There was no significant difference between tooth discolorations with materials in the presence of blood. However, in the absence of blood, Biodentine and ERRM exhibited less tooth discoloration than OrthoMTA.

Comparison of the effect of root canal preparation by using WaveOne and ProTaper on postoperative pain: a randomized clinical trial.

INTRODUCTION: WaveOne is a single-file reciprocating instrumentation system with the benefits of M-Wire alloy that has increased flexibility and improved resistance to cyclic fatigue over the conventional alloy. Root canal preparation techniques may cause postoperative pain. The goal of the present study was to compare the intensity and duration of postoperative pain when using WaveOne or ProTaper Universal systems for instrumentation of root canals. METHODS: Forty-two patients who fulfilled specific inclusion criteria were assigned to 2 groups according to the root canal instrumentation technique used, WaveOne or ProTaper Universal. Root canal treatment was carried out in 2 appointments, and the severity of postoperative pain was assessed by numerical rating scale (NRS) score after each session until complete pain relief was achieved. Analgesic consumption, duration of pain, and root canal preparation time were also recorded. RESULTS: The mean NRS score and duration of pain after both appointments were significantly higher in the WaveOne group (P < .05); however, the mean analgesic consumption was only significantly higher in the WaveOne group after the first appointment (P < .05). In all groups the highest mean NRS score was seen 6 hours after each therapeutic appointment. Canal preparation time was significantly shorter in the WaveOne group (P < .001). CONCLUSIONS: Postoperative pain was significantly lower in patients undergoing canal instrumentation with ProTaper Universal rotary instruments compared with the WaveOne reciprocating single-file technique.

The effect of MTAD, an endodontic irrigant, on fibroblast attachment to periodontally affected root surfaces: A SEM analysis.

BACKGROUND: Root surface debridement (RSD) is necessary to create an environment suitable for reattachment of the periodontium. Root surface conditioning may aid the formation of a biocompatible surface suitable for cell reattachment. BioPure™ MTAD (mixture of Doxycycline, citric acid and a detergent) is an endodontic irrigant with antibacterial properties and the ability to remove smear layer. It was hypothesized that MTAD may be useful for root surface conditioning. The efficacy of MTAD as a conditioner was measured by examining fibroblast attachment to root surfaces. MATERIALS AND METHODS: Thirty-two specimens of human teeth with advanced periodontal disease were used. The surfaces were root planed until smooth. Half of the specimens were treated with 0.9% saline and the other samples with Biopure MTAD. As a negative control group, five further samples were left unscaled with surface calculus. Human gingival fibroblast cells HGF1-PI1 were cultured and poured over the tooth specimens and incubated. After fixation, the samples were sputter-coated with gold and examined with a SEM. The morphology and number of attached, fixed viable cells were examined. The data was analysed using the Mann-Whitney-U statistical test. RESULTS: There was no significant difference between the numbers of attached cells in the experimental group treated with MTAD and the control group treated with saline. Little or no attached cells were seen in the negative control group. CONCLUSION: RSD created an environment suitable for cell growth and attachment in a laboratory setting. The use of MTAD did not promote the attachment and growth of cells on the surface of human roots following RSD.

The sealing ability of resilon and gutta-parcha following different smear layer removal methods: an ex vivo study.

OBJECTIVE: The objective of this study was to compare the ex-vivo sealing ability of Resilon/new Epiphany (SE) sealer to that of gutta-percha/AH-Plus following smear layer removal with EDTA or MTAD. STUDY DESIGN: One hundred extracted single-rooted human teeth were divided into 4 experimental groups and 2 positive and negative control groups. EDTA was used in groups 1 and 2. In groups 3 and 4 MTAD was used. The root canals were then obturated with gutta-percha/AH-Plus in groups 1 and 3 and Resilon/Epiphany (SE) in groups 2 and 4. After sterilization, the samples were coronally exposed to human saliva and monitored every 24 hours for 60 days. RESULTS: In groups 1, 2, 3, and 4, 45%, 65%, 90%, and 65% of specimens leaked within 60 days, respectively. There were statistically significant differences between group 1 and 3 (P < .05). CONCLUSIONS: Resilon/Epiphany (SE) system is as effective as gutta-percha/AH-Plus in preventing saliva leakage. MTAD did not adversely affect the sealing ability of Resilon/Epiphany (SE).