2000 Fiscal Year Final Research Report Summary
Analysis of the relationship between the invasion of dental caries-associated bacteria and the host response of dental pulp in human carious teeth with pulp exposure
| Project/Area Number |
11671897
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Conservative dentistry
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| Research Institution | The University of Tokushima, School of Dentistry |
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Principal Investigator |
NAKANISHI Tadashi Univ.of Tokushima, Conserv.Dent., Assistant professor, 歯学部・附属病院, 講師 (00217770)
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| Co-Investigator(Kenkyū-buntansha) |
SUGE Toshiyuki Univ.of Tokushima, Conserv.Dent., Instructor, 歯学部, 助手 (60243713)
NAKAE Hideaki Univ.of Tokushima, Conserv.Dent., Assistant professor, 歯学部, 助教授 (30227730)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Caries-associated bacteria / Pulpitis / Immunohistology / Macrophage / Fibroblast / Cyclooxygenase-2 / MCP-1 / MMP-1 |
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| Research Abstract |
We immunohistologically examined the prevalence and localization of 6 selected bacteria and the characteristics of pulpal response in human carious teeth with pulp exposure. Moreover, we investigated the interaction between caries-associated bacteria and pulpal fibroblasts to clarify the mechanism of pulpal tissue destruction in irreversible pulpitis.
Fourteen specimens were obtained from the extracted carious third molars with bactcrial invasion in reparative dentin and/or dental pulp for the immunohistological study. All of the samples showed the invasion of Lactobacillus plantarum in the reparative dentin. About 90% of the examined teeth showed the invasion of Lactobacillus casei, Streptococcus mutans and Peptostreptococcus micros in the reparative dentin. These 4 bacteria were also detected in the dental pulp with carious exposure. In relation to the host response of dental pulp, we examined the characteristics of MCP-1, MMP-1 and cyclooxygenase-2 (COX-2). These could be found in all of the inflamed pulp. MCP-1 and MMP-1 were mainly detected in macrophages in the area adjacent to bacterial invasion, and they were also detected in a small number of endothelial cells. In contrast, COX-2-expressing cells were mostly distributed close to the area of accumulation of inflammatory cells. In this predominant region of COX-2-expressing cells, COX-2 was principally expressed by fibroblasts rather than macrophages.
To elucidate the mechanism of the interaction between caries-associated bacteria and dental pulp, we investigated the expression of COX-2 in pulpal fibroblasts in response to S.mutans. The level of COX-2-specific mRNA from S.mutans-stimulated pulpal fibroblasts was significantly increased.
This study revealed the actual condition of the selected bacteria in deep-carious teeth with pulpal exposure. And this study also indicated that pulpal fibroblasts as well as macrophages may participate in the pulpal tissue destruction in irreversible pulpitis.
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Research Products
(10 results)
