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Wyatt TD, Roberts HW. Simulated Hydrostatic Pulpal Pressure Effect on Microleakage-An Initial Study. Oper Dent 2024; 49:290-299. [PMID: 38632850 DOI: 10.2341/23-123-l] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/15/2023] [Indexed: 04/19/2024]
Abstract
PURPOSE This study's purpose was to evaluate the effect of simulated in vitro hydrostatic pulpal pressure (HPP) on microleakage. METHODS AND MATERIALS Extracted third molars (n=12) were sectioned 5 mm below the cementoenamel junction, pulp tissue removed, and the sectioned crowns mounted on a Plexiglas plate penetrated by an 18-gauge stainless steel tube. The mounted specimen mesial surface received a 2×4×6 mm Class V preparation followed by restoration with a strongly acidic, one-step dental adhesive and a flowable microfilled resin, following all manufacturers' instructions. Restorations were finished to contour, and tubing was attached to a 20-cm elevated, 0.2% rhodamine G reservoir to the specimen steel tube for 48 hours. Specimens then received a nail polish coating to within 1 mm of the restoration margins and were placed in 2% methylene blue (MB) dye for 24 hours, followed by rinsing, embedding in epoxy resin, and sectioning into 1 mm slices using a diamond saw. Controls were intact molars (n=12) processed as above but without HPP. Specimen slices were evaluated using laser confocal microscopy with images exported to ImageJ software with microleakage assessed as the MB linear penetration as a percentage of the total interfacial wall length. Mean values were evaluated with the Kruskal Wallis/Dunn test at a 95% confidence level. RESULTS The control specimens demonstrated significantly greater (p<0.0001) MB penetration than experimental specimens with simulated HPP. Under this study's conditions, simulated HPP significantly decreased MB dye penetration. CONCLUSION Studies accomplished without simulated HPP may overestimate microleakage results.
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Affiliation(s)
- T D Wyatt
- Taylor D Wyatt DMD, dental student, University of Kentucky College of Dentistry, Lexington, KY, USA
| | - H W Roberts
- *Howard W Roberts DMD MS, associate professor, University of Kentucky College of Dentistry, Lexington, KY, USA
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Bordini EAF, Stuani VDT, Correa LE, Cassiano FB, Lovison MF, Leite ML, Hebling J, de Souza Costa CA, Soares DG. Chitosan-Calcium Aluminate as a Cell-homing Scaffold: Its Bioactivity Testing in a Microphysiological Dental Pulp Platform. Altern Lab Anim 2024; 52:107-116. [PMID: 38351650 DOI: 10.1177/02611929241232558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2024]
Abstract
In vitro models of the dental pulp microenvironment have been proposed for the assessment of biomaterials, to minimise animal use in operative dentistry. In this study, a scaffold/3-D dental pulp cell culture interface was created in a microchip, under simulated dental pulp pressure, to evaluate the cell-homing potential of a chitosan (CH) scaffold functionalised with calcium aluminate (the 'CHAlCa scaffold'). This microphysiological platform was cultured at a pressure of 15 cm H2O for up to 14 days; cell viability, migration and odontoblastic differentiation were then assessed. The CHAlCa scaffold exhibited intense chemotactic potential, causing cells to migrate from the 3-D culture to its surface, followed by infiltration into the macroporous structure of the scaffold. By contrast, the cells in the presence of the non-functionalised chitosan scaffold showed low cell migration and no cell infiltration. CHAlCa scaffold bioactivity was confirmed in dentin sialophosphoprotein-positive migrating cells, and odontoblastic markers were upregulated in 3-D culture. Finally, in situ mineralised matrix deposition by the cells was confirmed in an Alizarin Red-based assay, in which the CHAlCa and CH scaffolds were adapted to fit within dentin discs. More intense deposition of matrix was observed with the CHAlCa scaffold, as compared to the CH scaffold. In summary, we present an in vitro platform that provides a simple and reproducible model for selecting and developing innovative biomaterials through the assessment of their cell-homing potential. By using this platform, it was shown that the combination of calcium aluminate and chitosan has potential as an inductive biomaterial that can mediate dentin tissue regeneration during cell-homing therapies.
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Affiliation(s)
- Ester Alves Ferreira Bordini
- Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo (USP), Bauru, Brazil
| | - Vitor de Toledo Stuani
- Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo (USP), Bauru, Brazil
| | - Lígia Espoliar Correa
- Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo (USP), Bauru, Brazil
| | - Fernanda Balestrero Cassiano
- Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo (USP), Bauru, Brazil
| | - Marcella Fernandes Lovison
- Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo (USP), Bauru, Brazil
| | - Maria Luisa Leite
- Department of Oral Health Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, BC, Canada
| | - Josimeri Hebling
- Department of Orthodontics and Pediatric Dentistry, Araraquara School of Dentistry, São Paulo State University (UNESP), Araraquara, Brazil
| | - Carlos Alberto de Souza Costa
- Department of Physiology and Pathology, Araraquara School of Dentistry, São Paulo State University (UNESP), Araraquara, Brazil
| | - Diana Gabriela Soares
- Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo (USP), Bauru, Brazil
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Dentin Sialoprotein/Phosphophoryn (DSP/PP) as Bio-Inductive Materials for Direct Pulp Capping. Polymers (Basel) 2022; 14:polym14173656. [PMID: 36080731 PMCID: PMC9460548 DOI: 10.3390/polym14173656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 08/26/2022] [Accepted: 08/28/2022] [Indexed: 11/23/2022] Open
Abstract
Conventional direct pulp capping, such as calcium hydroxide (Ca(OH)2) or silicate products, usually induces an inflammatory reaction to provoke pulp regeneration. Phosphophoryn (PP) and dentin sialoprotein (DSP), the two most abundant non-collagenous proteins in the dentin matrix, are responsible for dentin mineralization, pulp cell migration, and differentiation. Here we examined the PP and combined DSP/PP as bio-inductive pulp capping materials by in vitro and in vivo tests. Firstly, the effects of the PP dose on pulp cell migration and matrix protein expression were examined by an agarose bead test. Secondly, the role of recombinant DSP (recDSP) and recDSP/PP on stimulating DSP-PP transcript expression was examined by RT-PCR. DSPP mRNA was also knocked down by RNA interference (RNAi) to examine their functions on dentin matrix mineralization. Finally, we used ferret animal models to test PP and recDSP/PP acting as capping agents on in vivo pulp responses and reparative dentin formation. The result showed that intermediate-dose PP was the most effective to enhance cell migration and differentiation. RecDSP/PP strongly enhanced the DSP-PP transcript expression, while inhibition of DSPP mRNA expression by siRNAs partially or completely affected dental pulp cell mineralization. The in vivo results showed that intermediate-dose PP and recDSP/PP proteins induced less pulp inflammation and promoted reparative dentin formation. Contrarily, conventional calcium hydroxide induced severe pulp inflammation. With these findings, DSP and PP could serve as capping agents for pulp capping therapy.
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He R, Chou C, Chen L, Stoller M, Kang M, Ho SP. Insights Into Pulp Biomineralization in Human Teeth. FRONTIERS IN DENTAL MEDICINE 2022. [DOI: 10.3389/fdmed.2022.883336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
IntroductionMineralized pulp (MP) compromises tooth function and its causation is unknown. The hypothesis of this study is that pulp mineralization is associated with pulpal tissue adaptation, increased mineral densities, and decreased permeabilities of tubular dentin and cementum. Methods will include correlative spatial mapping of physicochemical and biochemical characteristics of pulp, and contextualize these properties within the dentin-pulp complex (DPC) to reveal the inherent vunerabilities of pulp.MethodsSpecimens (N = 25) were scanned using micro X-ray computed tomography (micro-XCT) to visualize MP and measure mineral density (MD). Elemental spatial maps of MP were acquired using synchrotron X-ray fluorescence microprobe (μXRF) and energy dispersive X-ray spectroscopy (EDX). Extracted pulp tissues were sectioned for immunolabelling and the sections were imaged using a light microscope. Microscale morphologies and nanoscale ultrastructures of MP were imaged using scanning electron (SEM) and scanning transmission electron microscopy (STEM) techniques.ResultsHeterogeneous distribution of MD from 200 to 2,200 mg/cc, and an average MD of 892 (±407) mg/cc were observed. Highly mineralized pulp with increased number of occluded tubules, reduced pore diameter in cementum, and decreased connectivity in lateral channels were observed. H&E, trichrome, and von Kossa staining showed lower cell and collagen densities, and mineralized regions in pulp. The biomolecules osteopontin (OPN), osteocalcin (OCN), osterix (OSX), and bone sialoprotein (BSP) were immunolocalized around PGP 9.5 positive neurovascular bundles in MP. SEM and STEM revealed a wide range of nano/micro particulates in dentin tubules and spherulitic mineral aggregates in the collagen with intrafibrillar mineral surrounding neurovascular bundles. EDX and μXRF showed elevated counts of Ca, P, Mg, and Zn inside pulp and at the dentin-pulp interface (DPI) in the DPC.ConclusionColocalization of physical and chemical, and biomolecular compositions in MP suggest primary and secondary biomineralization pathways in pulp and dentin at a tissue level, and altered fluid dynamics at an organ level. Elevated counts of Zn at the mineralizing front in MP indicated its role in pulp biomineralization. These observations underpin the inherent mechano- and chemo-responsiveness of the neurovascular DPC and help elucidate the clinical subtleties related to pulpitis, dentin-bridge, and pulp stone formation.
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