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.

Melatonin as an Agent for Direct Pulp-Capping Treatment.

Melatonin plays an essential role in the regulation of bone growth. The actions that melatonin exerts on odontoblasts may be similar to its action on osteoblasts. This research aimed to evaluate the pulp response to melatonin used for direct pulp capping to evaluate the antioxidant effect of melatonin administered orally and its influence on dental pulp. Direct pulp capping was performed on the upper molars of Sprague Dawley rats using melatonin or Mineral Trioxide Aggregate (MTA). The study groups were: MTA; Melatonin; MTA + Melatonin administered orally; and Melatonin + Melatonin administered orally. In the latter two groups, the animals drank water dosed with melatonin ad libitum (10 mg/100 mL). After 30 days, the animals were sacrificed, and 5 ml of blood, the kidneys, and the liver were extracted in order to evaluate oxidative stress using thiobarbituric acid reactive substances testing (TBARS). Fragments of the maxilla containing the study molars were prepared for histological evaluation. The degree of pulp inflammation and pulp necrosis, the presence of reparative dentin and dentin bridging the pulp chamber, the presence and regularity of the odontoblastic layer, and the presence of pulp fibrosis were evaluated. No significant differences were found between the four study groups for any of the studied histological variables. The oral administration of melatonin did not modify the local effects of MTA or melatonin on dental pulp, or reduce basal-level oxidative stress. The effect of melatonin on pulp is similar to that of MTA and may be used as an agent for direct pulp capping.

Histological evaluation of hard tissue formation after direct pulp capping with a fast-setting mineral trioxide aggregate (RetroMTA) in humans.

OBJECTIVES: To histologically evaluate the morphology of the newly formed mineralized tissue and of the adjacent cells, in intact human teeth subjected to mechanical pulp exposure and capping with a fast-setting mineral trioxide aggregate (RetroMTA). MATERIALS AND METHODS: Seven caries-free third molars from three adults were subjected to pulp exposure, direct capping with RetroMTA, and restoration with a composite resin. Seven months later, the teeth were clinically and radiographically evaluated, extracted, and subjected to histological processing and evaluation. RESULTS: All teeth were clinically and radiographically inconspicuous and showed no presence of severe inflammatory reactions. Bacteria were absent in all teeth. All cases exhibited some degree of mineralized tissue in the area of exposure to varying extent. This newly formed mineralized tissue was mostly atubular and did not display the features of regular dentine in any of the cases. No cells exhibiting the features of odontoblasts or odontoblast-like cells were observed. Instead, the cells exhibited a flat or cuboidal shape, resembling fibroblasts. CONCLUSIONS: When the exposed pulps were directly capped with RetroMTA, the new calcified hard tissue was not "regular dentine," and did not seem to be the product of genuine odontoblast differentiation. These results suggest that the formation of calcified tissues after direct pulp capping with RetroMTA may be more appropriately regarded as a reparative process than as a genuine regeneration response. CLINICAL RELEVANCE: This is the first histological study on humans showing that regular dentine was not regenerated when a bioactive pulp-capping material (RetroMTA) was placed over exposed pulp tissue. TRIAL REGISTRATION: NCT03631511.

Dentine-pulp tissue engineering in miniature swine teeth by set calcium silicate containing bioactive molecules.

OBJECTIVE: The present study aims to investigate whether reparative dentinogenesis could be guided at central pulpal sites or at a distance from the amputated pulp of miniature pig teeth, by using set calcium silicate-based carriers containing human recombinant bioactive molecules. DESIGN: Pulp exposures were performed in 72 permanent teeth of 4 healthy miniature swine. The teeth were capped with pre-manufactured implants of set calcium silicate-based material containing BMP-7, TGFß1 or WnT-1, for 3 weeks. Conical-shaped intrapulpal implants were exposed in the central pulp core, while disc-shaped extrapulpal implants were placed at a distance from the amputated pulp. Implants without bioactive molecules were used as controls. Thickness and forms of new matrix mineralized deposition were assessed histologically at post-operative periods of 3 weeks by light microscopy. RESULTS: Intrapulpal applications: Calcified structures composed of osteodentine were found in contact with the BMP-7 implants. An inhomogeneous calcified tissue matrix was found around the WnT-1 carriers. A two-zone calcified structure composed of osteodentine and a thicker tubular matrix zone was seen at the TGFß1 carrier-pulp interface. Extrapulpal applications: The space between WnT-1 implants and pulp periphery had been invaded by soft tissue with traces of calcified foci. Thick calcified structures composed of osteodentine were found surrounding pulp exposure sites in response to application of BMP-7. Spindle-shaped cells associated with atubular calcified matrix or elongated polarized cells associated with tubular dentine-like matrix were found along the cut dentinal walls of the TGFß1 group. CONCLUSION: The present experiments indicated that set calcium silicate could be used as carrier for biologically active molecules. TGFß1 was shown to be an effective bioactive molecule in guiding tertiary dentine formation.

Simvastatin Promotes Dental Pulp Stem Cell-induced Coronal Pulp Regeneration in Pulpotomized Teeth.

INTRODUCTION: Pulpotomy is a specific treatment used to save root pulp, in which only the inflamed coronal pulp is removed and capping materials are placed. Our study aims to study the effect of simvastatin (1) on the proliferation and differentiation of dental pulp stem cells (DPSCs) and (2) on DPSC-induced pulp regeneration after pulpotomy. METHODS: DPSCs were treated with different concentrations of simvastatin. Cell counting kit-8 activity was examined to test cell proliferation, and alkaline phosphatase assays and alizarin red S staining were conducted to examine differentiation. In addition, DPSCs pretreated with simvastatin were transplanted into the dorsum of CB-17 severe combined immunodeficiency mice. Areas of mineralized tissue were compared. Eighteen immature premolars from 2 beagle dogs were divided into 4 groups and treated by pulpotomy: the mineral trioxide aggregate, absorbable gelatin sponge, canine DPSCs (cDPSCs), and simvastatin groups. The teeth were extracted after 10 weeks, and the areas of regenerated pulp and dentin were calculated and compared. RESULTS: Simvastatin at 1 µmol/L suppressed cDPSCs proliferation but significantly increased alkaline phosphatase activity and mineral nodule formation. In addition, cDPSCs pretreated with 1 µmol/L simvastatin formed significantly more mineralized tissue in CB-17 severe combined immunodeficiency mice. In the in vivo study, the ratios of the areas of pulp and dentin regeneration were 47.3% ± 2.5%, 76.8% ± 4.3%, and 85.8% ± 0.9%, respectively, in the absorbable gelatin sponge, cDPSCs, and simvastatin groups. CONCLUSIONS: Simvastatin stimulates cDPSCs mineralization both in vivo and in vitro. It also promotes DPSC-induced pulp and dentin regeneration after pulpotomy.

Preliminary Evaluation of Platelet Rich Fibrin-Mediated Tissue Repair in Immature Canine Pulpless Teeth.

OBJECTIVE: To evaluate the use of platelet-rich fibrin (PRF) in the regenerative therapy of immature canine permanent teeth. METHODS: Eight immature premolars of beagle dogs were pulp extracted and cleaned with irrigation, then divided into two groups of empty root canals and those filled with a PRF clot. All of the eight premolars were sealed with mineral trioxide aggregate and glass ionomer cement. Two premolars were left naturally grown as a positive control. The root development was assessed radiographically and histologically after 12 weeks. RESULTS: The radiological findings showed greater increases in the thickness of lateral dentinal wall in the PRF group than in the vacant group. Histologically, dental-associated mineral tissue, connective tissue, and bone-like mineral tissue grew into the root canals independent of PRF clot use. The PRF was able to increase the thickness of dental-associated mineral tissue. However, the vital tissue differed from the pulp dentin complex. CONCLUSION: Our study demonstrated the feasibility of using PRF-mediated regenerative therapy in pulpless immature teeth for improving tissue repair.

Combined effects of mineral trioxide aggregate and human placental extract on rat pulp tissue and growth, differentiation and angiogenesis in human dental pulp cells.

OBJECTIVE: The aim of this study was to evaluate the combined effects of mineral trioxide aggregate (MTA) and human placental extract (HPE) on cell growth, differentiation and in vitro angiogenesis of human dental pulp cells (HDPCs) and to identify underlying signal transduction mechanisms. In vivo dental pulp responses in rats for a pulp-capping agent were examined. MATERIALS AND METHODS: MTS assay. ALP activity test, alizarin red S staining and RT-PCR for marker genes were carried out to evaluate cell growth and differentiation. HUVEC migration, mRNA expression and capillary tube formation were measured to evaluate angiogenesis. Signal transduction was analysed using Western blotting and confocal microscopy. The pulps of rat maxillary first molars were exposed and capped with either MTA or MTA plus HPE. Histologic observation and scoring were performed. RESULTS: Compared to treatment of HDPCs with either HPE or MTA alone, the combination of HPE and MTA increased cell growth, ALP activity, mineralized nodules and expression of marker mRNAs. Combination HPE and MTA increased migration, capillary tube formation and angiogenic gene expression compared with MTA alone. Activation of Akt, mammalian target of rapamycin (mTOR), p38, JNK and ERK MAPK, Akt, and NF-κB were significantly increased by combining HPE and MTA compared with MTA alone. Pulp capping with MTA plus HPE in rats showed superior dentin bridge formation, odontoblastic layers and dentinal tubules and lower inflammatory cell response, compared to the MTA alone group. CONCLUSIONS: This study demonstrates for the first time that the use of MTA with HPE promotes cell growth, differentiation and angiogenesis in HDPCs, which were associated with mTOR, MAPK and NF-κB pathways. Direct pulp capping with HPE plus MTA showed superior results when compared with MTA alone. Thus, the combination of MTA and HPE may be useful for regenerative endodontics.

Histological evaluation of direct pulp capping of rat pulp with experimentally developed low-viscosity adhesives containing reparative dentin-promoting agents.

OBJECTIVES: This study examines the wound healing process in exposed rat pulp when capped with experimental adhesive resin systems. METHODS: Experimental adhesive resin system for direct pulp capping was composed of primer-I (PI), -II (PII), and -III (PIII) and an experimental bonding agent (EBA). PI was Clearfil(®) SE Bond(®)/Primer (CSP) containing 5.0 wt% CaCl2, PII was PI containing 10 wt% nanofiller (Aerosil(®) 380), and PIII was CSP containing 5.0 wt% of compounds of equal moles of synthetic peptides (pA and pB) derived from dentin matrix protein 1. EBA was Clearfil(®) SE Bond(®)/Bond (CSB) containing 10 wt% hydroxyapatite powders. Three experimental groups were designed. PI was assigned to experimental Groups 1 and 3. PII was assigned to experimental Groups 2 and 3. PIII and EBA were assigned to all experimental adhesive groups. Control teeth were capped with calcium hydroxide preparation (Dycal(®)), and CSP and CSB were applied to the cavity. The rats were sacrificed after each observation period (14, 28, 56, and 112 days). The following parameters were evaluated: pulp tissue disorganization, inflammatory cell infiltration, reparative dentin formation (RDF), and bacterial penetration. RESULTS: There were no significant differences among all the groups for all parameters and all observation periods (p>0.05, Kruskal-Wallis test). All groups showed initial RDF at 14 days postoperatively and extensive RDF until 112 days postoperatively. Groups 2 and 3 demonstrated higher quantity of mineralized dentin bridge formation compared with Group 1. CONCLUSIONS: Addition of nanofillers to the primer was effective in promoting high-density RDF. CLINICAL SIGNIFICANCE: Experimentally developed adhesive resin systems induce the exposed pulp to produce almost the same quantity of reparative dentin as calcium hydroxide. However, we need further studies to elucidate whether the same results could be obtained in humans.

Histological Effects of Enamel Matrix Derivative on Exposed Dental Pulp.

INTRODUCTION: Direct pulp capping procedure is a therapeutic application of a drug on exposed tooth pulp in order to ensure the closure of the pulp chamber and to allow the healing process to take place. OBJECTIVE: The aim of this study was to examine the histological effects of Emdogain® on exposed tooth pulp of a Vietnamese pig (Sus scrofa verus). METHODS: The study comprised 20 teeth of a Vietnamese pig. After class V preparation on the buccal surfaces of incisors, canines and first premolars, pulp was exposed. In the experimental group, the perforations were capped with Emdogain® (Straumann, Basel, Switzerland), while in the control group pulp capping was performed with MTA® (Dentsply Tulsa Dental, Johnson City, TN, USA). All cavities were restored with glass-ionomer cement (GC Fuji VIII, GC Corporation, Tokyo, Japan). The observational period was 28 days, after which the animal was sacrificed and histological preparations were made. A light microscope was used to analyze dentin bridge formation, tissue reorganization and inflammation, and the presence of bacteria in the pulp. RESULTS: The formation of dentin bridge was observed in the experimental and control groups. Inflammation of the pulp was mild to moderate in both groups. Angiogenesis and many odontoblast-like cells, responsible for dentin bridge formation, were observed. Necrosis was not observed in any case, nor were bacteria present in the pulp. CONCLUSION: Histological analysis indicated a favorable therapeutic effect of Emdogain® Gel in direct pulp capping of Vietnamese pigs. Pulp reaction was similar to that of MTA®.

Direct Pulp Capping with Calcium Hydroxide or Mineral Trioxide Aggregate: A Meta-analysis.

INTRODUCTION: The purpose of this study was to compare the effectiveness of mineral trioxide aggregate (MTA) and calcium hydroxide (CH) as pulp capping materials in humans by means of a meta-analysis. METHODS: The PubMed, Cochrane Library, Embase, and Web of Knowledge databases were used in the literature search from their establishment date until December 7, 2014. Studies that met the inclusion criteria were accepted, and necessary information was extracted by 2 authors independently using a standardized form. The success rate, inflammatory response, and dentin bridge formation were evaluated. RESULTS: Thirteen studies met the inclusion criteria. There was no significant heterogeneity between studies, so a fixed-effects model was used. The MTA treatment groups showed a significantly higher success rate compared with CH-capped groups (randomized controlled trials: odds ratio [OR] = 2.26; 95% confidence interval [CI] = 1.33-3.85; P = .003; retrospective nonrandomized trials: OR = 2.88; 95% CI, 1.86-4.44; P < .00001). MTA was superior to CH in terms of the absence of an inflammatory response as well as dentin bridge formation, with the OR being 4.56 (95% CI, 2.65-7.83) and 3.56 (95% CI, 1.89-6.70), respectively. CONCLUSIONS: MTA has a higher success rate and results in less pulpal inflammatory response and more predictable hard dentin bridge formation than CH. MTA appears to be a suitable replacement of CH used for direct pulp capping.

Promotion of Dental Pulp Cell Migration and Pulp Repair by a Bioceramic Putty Involving FGFR-mediated Signaling Pathways.

Mineral trioxide aggregate is the currently recommended material of choice for clinical pulp repair despite several disadvantages, including handling inconvenience. Little is known about the signaling mechanisms involved in bioceramic-mediated dental pulp repair-particularly, dental pulp cell (DPC) migration. This study evaluated the effects of iRoot BP Plus, a novel ready-to-use nanoparticulate bioceramic putty, on DPC migration in vitro and pulp repair in vivo, focusing on possible involvement of fibroblast growth factor receptor (FGFR)-related signaling, including mitogen-activated protein kinase and Akt pathways. Treatment with iRoot BP Plus extracts enhanced horizontal and vertical migration of DPCs, which was comparable with the effects induced by mineral trioxide aggregate extracts. The DPCs exposed to iRoot BP Plus extracts demonstrated no evident apoptosis. Importantly, treatment with iRoot BP Plus extracts resulted in rapid activation of FGFR, p38 mitogen-activated protein kinase, extracellular signal-regulated kinase (ERK) 1/2, c-Jun-N-terminal kinase (JNK), and Akt signaling in DPCs. Confocal immunofluorescence staining revealed that iRoot BP Plus stimulated focal adhesion formation and stress fiber assembly in DPCs, in addition to upregulating the expression of focal adhesion molecules, including p-focal adhesion kinase, p-paxillin, and vinculin. Moreover, activation of FGFR, ERK, JNK, and Akt were found to mediate the upregulated expression of focal adhesion molecules, stress fiber assembly, and enhanced DPC migration induced by iRoot BP Plus. Consistent with the in vitro results, we observed induction of homogeneous dentin bridge formation and expression of p-focal adhesion kinase, p-FGFR, p-ERK 1/2, p-JNK, and p-Akt near injury sites by iRoot BP Plus in an in vivo pulp repair model. These data demonstrate that iRoot BP Plus can promote DPC migration and pulp repair involving the FGFR-mediated ERK 1/2, JNK, and Akt pathways. These findings provide valuable insights into the signaling mechanisms underlying nanoparticulate bioceramic-mediated pulp repair.

Dentinogenic responses after direct pulp capping of miniature swine teeth with Biodentine.

INTRODUCTION: The aim of this study was to evaluate pulpal responses after experimental direct pulp capping of mechanically exposed teeth with a new calcium silicate-based dentin replacement material. METHODS: Thirty-four anterior and posterior teeth of 3 miniature swine were used. Class V or I cavities were prepared on the buccal or occlusal surfaces, respectively. Pulpal exposures were further performed using a round carbide bur 0.8 mm in diameter. Exposures were treated with white MTA Angelus (Angelus, Londrina, PR, Brazil) or Biodentine (Septodont, Saint Maur des Fosses, France), and the cavities were further restored with Biodentine. The pulpal tissue responses were histologically assessed at postoperative periods of 3 and 8 weeks. Data were statistically analyzed using the Kruskal Wallis and the Mann-Whitney U tests. RESULTS: Inflammatory infiltration or pulp tissue necrosis was not found in any of the specimens. All teeth showed mineralized matrix formation in the form of a complete hard tissue bridge composed of osteodentin or osteodentin followed by a discontinuous or continuous reparative dentin zone. A significantly higher thickness of the hard tissue bridge was found in the group of teeth treated with Biodentine at both 3 and 8 weeks. A number of teeth, which were under root development at the onset of the experimental procedures, exhibited ectopic pulp calcification. CONCLUSIONS: The application of both calcium silicate-based materials in direct contact with the mechanically exposed pulp of healthy miniature swine teeth led to pulp repair with complete hard tissue bridge formation. The thickness of hard tissue bridges was significantly higher after pulp capping with Biodentine.

Initial transient accumulation of M2 macrophage-associated molecule-expressing cells after pulpotomy with mineral trioxide aggregate in rat molars.

INTRODUCTION: M2 (alternatively activated) macrophages are known to participate in wound healing and tissue repair. This study aimed to analyze the temporospatial changes in the distribution and density of M2 macrophage-associated molecule-expressing cells after pulpotomy with mineral trioxide aggregate (MTA) in rat molars to ascertain the role played by M2 macrophages in the healing of MTA-capped pulp tissue. METHODS: The maxillary first molars of 8-week-old Wistar rats were pulpotomized and capped with MTA. After 1-14 days, the teeth were examined after hematoxylin-eosin staining or immunoperoxidase staining of CD68 (a general macrophage marker) and M2 macrophage markers (CD163 and CD204). The density of positively stained cells was enumerated in the surface and inner regions (0-100 µm and 300-400 µm, respectively, from the wound surface). RESULTS: MTA capping initially caused mild inflammatory changes and the formation of a degenerative layer followed by progressive new matrix formation and calcified bridging. At 1-2 days, CD68-, CD163-, and CD204-positive cells started to accumulate beneath the degenerative layer, and the density of these cells was significantly higher in the surface region than in the inner region (P < .05). From 7 days onward, the 3 types of cells displayed an almost normal distribution beneath the newly formed dentinlike matrix. CONCLUSIONS: After the pulpotomy of rat molars with MTA, M2 macrophage-associated molecule-expressing cells transiently accumulated beneath the degenerative layer under the MTA. This suggests that M2 macrophages participate in the initial phases of the healing of MTA-capped pulp tissue.

The plasma-rich in growth factor as a suitable matrix in regenerative endodontics: a case series.

The aim of this report is to describe the positive effect of plasma-rich in growth factor (PRGF) on pulp regeneration and apex formation in cases with necrotic pulps and open apices. After access cavity preparation and cleaning of the canal, triple antibiotic paste was inserted into the canals for the purpose of disinfection. After two weeks, apical bleeding was mechanically created by insertion of a #80 file through the apex. PRGF obtained from the patient was centrifuged and injected into the canals up to the level of the cementoenamel junction; the teeth were restored temporarily. The patients returned for review two weeks later. If there was absence of pain, swelling, fistula or any other complication, the teeth were sealed with MTA and composite. At 22 months follow-up, complete apex closure in two teeth and apical closure and continued increase of dentinal wall thickness in two other cases were evident.

Effects of a triple antibiotic solution on pulpal dynamics after intentionally delayed tooth replantation in mice.

INTRODUCTION: This study analyzed the detailed biological events underlying pulpal dynamics evoked by 3Mix (the mixture of ciprofloxacin, metronidazole, and minocycline) solution after intentionally delayed tooth replantation because 3Mix improves pulpal healing after tooth injuries. METHODS: The maxillary first molars of 3-week-old mice were extracted and immersed in 3Mix solution for 30 minutes in comparison with phosphate buffered saline (PBS) alone. Cell proliferation, apoptosis, and differentiation were assessed in extracted/replanted teeth during days 0-14 using immunohistochemistry, apoptosis assay, and reverse-transcriptase polymerase chain reaction. RESULTS: 3Mix solution accelerated odontoblast differentiation in the coronal pulp on day 7 and tertiary dentin formation on day 14, whereas the regenerative process was delayed in the PBS group. Cell proliferation and apoptosis occurred in the pulp of the 3Mix group during days 5-7 and subsequently decreased from days 7-14. On day 5, dentin sialophosphoprotein and nestin were first recovered in the 3Mix group, whereas expression levels for alkaline phosphatase, osteopontin, and osteocalcin increased in the PBS group. The expression levels for octamer-binding factor 3/4A and 3/4B reached the maximum level on day 1 and were sharply decreased on day 3 in both groups. High expression levels of Cd11c were first observed in the 3Mix group on day 1 and later at days 5 and 7. CONCLUSIONS: The results suggest that the application of 3Mix may suppress osteoblast differentiation by the migration of dendritic cells to the injury site and via the activation of stem/progenitor cells, resulting in the acceleration of odontoblastlike cell differentiation.

Pulpal response to nano hydroxyapatite, mineral trioxide aggregate and calcium hydroxide when used as a direct pulp capping agent: an in vivo study.

UNLABELLED: Nano hydroxyapatite (Nano-HA) and Mineral Trioxide Aggregate (MTA) because of its better qualities can be used as an alternative to calcium hydroxide in direct pulp capping procedures. The aim of the study was to compare the response of exposed human pulp to Nano-HA, Mineral Trioxide Aggregate and calcium hydroxide. STUDY DESIGN: The study was done on 30 premolars, ranging from patients between 11-15 years. Intentional pulp capping was done using one of the experimental materials. The extracted teeth were then subjected to staining procedure and evaluated for dentin bridge and pulpal response after 15 and 30 days. Intragroup comparisons of the observed values were analyzed using Chi-square test. RESULTS: Nano-HA and MTA produced continuous dentin bridges. Dentin bridge that was formed in MTA group had regular pattern of dentinal tubules but no tubules were seen in the nano-HA group. Dentin bridge was not observed in Dycal group for the 15 days period in majority of the sample and by 30 days dentin bridge was observed that were both continuous and interrupted in equal number of samples. The initial inflammatory response and necrosis was more with Nano-HA and calcium hydroxide which reduced with time. CONCLUSION: MTA showed no inflammatory changes in majority of the samples in both the study periods. Necrosis was least observed in MTA group followed by Nano-HA. Vascularity increased in Nano-HA group in the initial periods which reduced with increasing time. Based on the ability of nano-HA to produce complete dentinal bridges, favorable cellular and vascular response, the material could be considered as an substitute and could be tried used as a direct pulp capping agent.

Comparison of pulpal responses to pulpotomy and pulp capping with biodentine and mineral trioxide aggregate in dogs.

INTRODUCTION: This study evaluated the pulpal and periapical responses of dogs' teeth after pulpotomy and pulp capping with a new tricalcium silicate-based cement (Biodentine) when compared with mineral trioxide aggregate (MTA) by radiographic, histopathologic, and histomicrobiological analyses. METHODS: Sixty roots (30 teeth) of dogs were divided into 2 groups, Biodentine (n = 36 roots) and ProRoot MTA (control, n = 24 roots). Animals were killed after 120 days, and the teeth were subjected to histotechnical processing (hematoxylin-eosin and Brown and Brenn staining). Qualitative and quantitative histopathologic data were analyzed by Fisher exact and Mann-Whitney tests (α = 0.05). RESULTS: Radiographically, mineralized tissue bridge formation was observed in more specimens treated with Biodentine (96.8%) than with MTA (72.2%) (P = .02). Integrity of the lamina dura and absence of periapical bone rarefaction and root resorption (external and internal) were observed in all specimens. Histopathologic and histomicrobiological analyses revealed mineralized tissue bridge formation, pulpal vitality, odontoblast layer integrity, preserved periodontal ligament, and absence of bone or root resorption and microorganisms in both groups. Although the bridges formed at the amputation site had similar morphology, they were significantly thicker in the Biodentine group (P < .0001). Comparison between the radiographic and histopathologic results showed that radiographic visualization of more bridges in the Biodentine group was related to bridge thickness because radiographic diagnosis was flawed for bridges with thickness less than 0.5 mm. Fluorescence microscopy improved the visualization of bridge structure. CONCLUSIONS: Biodentine presented tissue compatibility and allowed for mineralized tissue bridge formation after pulpotomy in all specimens with similar morphology and integrity to those formed with use of MTA. Periapical radiographs failed in detecting mineralized tissue bridges with thickness less than 0.5 mm.

Capping a pulpotomy with calcium aluminosilicate cement: comparison to mineral trioxide aggregates.

INTRODUCTION: Calcium aluminate cements have shown little affinity for bacterial growth, low toxicity, and immunogenicity when used as a restoration material, but calcium aluminate cements have not been tested in vivo in pulpotomy procedures. METHODS: To address this question, a calcium aluminosilicate cement (Quick-Set) was tested along with 2 mineral trioxide aggregates, ProRoot MTA and MTA Plus. These cements were used as a capping agent after pulpotomy. Control rats had no pulpotomy, or the pulpotomy was not capped. Proinflammatory cytokines interleukin (IL)-1ß and IL-1α were measured, and histology was performed at 30 and 60 days after capping. The nociceptive response was determined by measuring the lengthening of the rat's meal duration. RESULTS: and CONCLUSIONS: IL-1ß and IL-1α concentrations were reduced in the capped teeth, but no differences were observed among the 3 cements. Dentinal bridging could be detected at both 30 and 60 days with each of the 3 cements, and the pulps were still vital 60 days after capping. Meal duration significantly shortened after placement of the 3 different cements, indicating a nociceptive response, but there were no differences among the materials. Calcium aluminosilicate cement had similar properties to mineral trioxide aggregates and is a viable option for pulpotomy procedures.

Iloprost induces tertiary dentin formation.

INTRODUCTION: Prostacyclin (PGI2), a member of the prostaglandin family, can promote angiogenesis and cell proliferation. METHODS: In this study, the effect of the application of a PGI2 analog (iloprost) on dentin repair was examined in vitro and in vivo. RESULTS: Iloprost significantly stimulated the expression of vascular endothelial growth factor and osteo-/odontogenic marker messenger RNA in human dental pulp cells (HDPCs) under osteoinductive conditions in vitro. In addition, iloprost enhanced HDPC alkaline phosphatase enzymatic activity and mineral deposition. An in vivo study was performed using a rat molar mechanical pulp exposure model. After 30 days, histologic analysis revealed that there was a dramatic tertiary dentin formation in the iloprost-treated group compared with the calcium hydroxide and the untreated control groups. Furthermore, vascular endothelial growth factor protein expression in dental pulp tissue was increased in the iloprost-treated group as determined by immunohistochemical staining. CONCLUSIONS: Taken together, the present study, for the first time, shows that iloprost induces the expression of osteo-/odontogenic markers in vitro and promotes angiogenic factor expression and enhances tertiary dentin formation in vivo. This implies the potential clinical usefulness of iloprost in vital pulp therapy.

Physical properties and biological/odontogenic effects of an experimentally developed fast-setting α-tricalcium phosphate-based pulp capping material.

BACKGROUND: Recently, fast-setting α-tricalcium-phosphate (TCP) cement was developed for use in the pulp capping process. The aim of this study was to investigate the physical properties and biological effects of α-TCP cement in comparison with mineral trioxide aggregate (MTA). METHODS: We measured the setting time, pH values, compressive strength, and solubility of the two materials. We evaluated biocompatibility on the basis of cell morphology and a viability test using human dental pulp cells (hDPCs). Chemical composition of each material was analyzed by energy dispersive x-ray spectroscopic (EDS) analysis. The expression of odontogenic-related genes was evaluated by Western blotting and immunofluorescence. The calcified nodule formation was measured by Alizarin red staining. We performed the pulp capping procedure on rat teeth for histological investigation. The data were analyzed by an independent t-test for physical properties, one-way ANOVA for biological effects, and the Mann-Whitney U test for tertiary dentin formation. A P value of less than 0.05 was considered statistically significant for all tests. RESULTS: The setting time, pH values, and compressive strength of α-TCP was lower than that of MTA (P < 0.05); however, the solubility of α-TCP was higher than that of MTA (P < 0.05). The resultant cell viability observed with the two materials was similar (P > 0.05). Scanning electron microscopy (SEM) revealed that cells attached to both materials were flat and had cytoplasmic extensions. The expression of odontogenic-related markers and mineralized nodule formation were higher in the two experimental groups compared to the control group (P < 0.05). Continuous tertiary dentin was formed underneath the capping materials in all samples of the tested groups. CONCLUSIONS: Our study demonstrated that the α-TCP exhibited biocompatibility and odontogenicity comparable to MTA, whereas it had a quicker setting time.