| Project/Area Number |
23K16013
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 57030:Conservative dentistry-related
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| Research Institution | Hokkaido University |
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Principal Investigator |
劉 雲青 北海道大学, 歯学研究院, 博士研究員 (50962320)
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| Project Period (FY) |
2023-04-01 – 2026-03-31
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| Project Status |
Granted (Fiscal Year 2023)
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| Budget Amount *help |
¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2025: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2024: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2023: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
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| Keywords | direct pulp capping / calcium hydroxide / platinum nanoparticles / angiogenesis / inflammatory / polyphosphoric acid / phosphorylated pullulan / MTA |
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| Outline of Research at the Start |
CPN reduce the inflammation and induce numerous blood vessels in the dental pulp exposure area. PPA plays critical roles in bone regeneration and PPL used as a carrier for growth factors in hard tissue engineering. Based on the above-mentioned properties of CPN and carriers PPA/PPL, these materials combined with MTA/CH materials may contribute to the development of a novel experimental pulp capping material.
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| Outline of Annual Research Achievements |
We aim to develop an experimental pulp capping material by the incorporation Colloidal platinum nanoparticles (CPN) with the commercially available pulp capping agent calcium hydroxide (CH). Initially, we assessed the pulpal tissue response in Wistar rats following the application of three different CPN materials at day 1, 7, 14, and 28 subsequent to direct pulp capping. The dental pulps were mechanically exposed and randomly divided into three groups based on the CPN materials applied: group 1- PAA-PT (platinum, poly acrylic acid, water), group 2- C-PT (platinum, sodium citric acid, water) and group 3- C-CYD (platinum, sodium citric acid, γ-cyclodextrin, water). All cavities were then restored using Super Bond-SB. A negative control (SB) was also included. At day 1, no or mild inflammatory responses were observed in all three CPN groups, significantly differing from the SB group (p<0.05), except C-PT group. At day 3, numerous blood vessels with no or mild inflammation were observed in the C- CYD group, indicating rapid angiogenesis, which was significantly different from SB groups (p<0.05), whereas PAA-PT and C-PT groups showed mild to moderate inflammatory responses. At day 7, no or mild inflammation was observed in the C-CYD group significantly differing from the PAA-PT, C-PT and SB groups (p<0.05), whereas mild or moderate inflammatory responses were observed in all other groups.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
Last year, we evaluated the healing responses of the colloidal platinum nanoparticles (CPN).
CPN is being incorporated into pulp capping agent calcium hydroxide (CH). A positive control (CH) is also included.
The expression of angiogenesis, inflammation, and mineralization-related markers such as CD34, CD45, VEGFs; IL-6, IL-10; ALP, Runx2, OCN (immunohistochemistry) will be checked.
The mechanical properties including microhardness, compressive strength, setting time will be checked for screening out the optimal experimental pulp capping material.
On the other hand, the adhesion ability of the experimental pulp capping material to dental hard tissue is being evaluated (SEM, TEM, EDS, and FTIR).
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| Strategy for Future Research Activity |
Histological preparation: by the end of October 2024, the histological response of exposed dental pulp to the combined material will be evaluated using Hematoxylin-Eosin staining (histological observation), details were taken concerning the hard tissue bridge (continuity, morphological aspects, thickness, localization); Mechanical properties analysis: by the end of December 2024; Immunohistochemical preparation: by the end of August 2025; Data acquisition: by the end of September 2025; Data analysis: by the end of October 2025; Preparation of a draft for the manuscript: by the end of January 2026; Manuscript submission for publication: by the end of March 2026.
In our present study evaluation, the healing responses of colloidal platinum nanoparticles on dental pulp were very satisfactory. Therefore, calcium hydroxide combined with colloidal platinum nanoparticles could be the material of choice for direct pulp capping, which will be our next future research work.
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