Microbiological studies of carious dentine from human teeth with irreversible pulpitis

Hahn, Chin‐Lo; Falkler, William A.; Minah, Glenn E.

doi:10.1016/0003-9969(91)90077-8

Cited by 113 publications

(110 citation statements)

References 39 publications

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“…Although various components of Gram-negative bacteria can activate many immunomodulating receptors (Akira et al, 2006), analysis of our RNA-silencing data affirms a prominent role of TLR4 in the activation of odontoblast responses to these bacteria. These results are shown in both hOD clones and are also supported by: (1) our previous findings in human odontoblasts maintained in natural teeth (Veerayutthwilai et al, 2007); and (2) previous clinical data showing that the recovery of Gramnegative bacteria (e.g., Prevotella, Porphyromonas, and Fusobacterium) and their LPS from caries lesions was closely associated with pain and thermal hypersensitivity, which strongly indicates an extensive underlying pulpitis (Hahn et al, 1991(Hahn et al, , 1993Massey et al, 1993;Khabbaz et al, 2000;Hahn and Liewehr, 2007).…”

Section: Tlr4 Silencing Diminished Odontoblast Immune Responses To Grsupporting

confidence: 85%

TGF-β1 Inhibits TLR-mediated Odontoblast Responses to Oral Bacteria

et al. 2009

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A supplemental appendix to this article is published electronically only at http://jdr.sagepub.com/supplemental. ABSTRACT TGF-β1 exerts diverse functions in tooth development and tissue repair, but its role in microbial defenses of the tooth is not well-understood. Odontoblasts extending their cellular processes into the dentin are the first cells to recognize signals from TGF-β1 and bacteria in carious dentin. This study aimed to determine the role of TGF-β1 in modulating odontoblast responses to oral bacteria. We show that these responses depend upon the expression levels of microbial recognition receptors TLR2 and TLR4 on the cell surface. Porphyromonas gingivalis, Prevotella intermedia, and Fusobacterium nucleatum activated both TLRs, but TLR4 played a greater role. Lack of cell-surface TLR2 was associated with poor response to Streptococcus mutans, Enterococcus faecalis, and Lactobacillus casei. TGF-β1 inhibited TLR2 and TLR4 expression and attenuated odontoblast responses. Our findings suggest that the balance between TLR-mediated inflammation and TGF-β1 anti-inflammatory activity plays an important role in pulpal inflammation.

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Section: Tlr4 Silencing Diminished Odontoblast Immune Responses To Grsupporting

confidence: 85%

TGF-β1 Inhibits TLR-mediated Odontoblast Responses to Oral Bacteria

et al. 2009

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“…Up to 31 different taxa were detected in each of the 10 carious dentine samples, similar to the diversity reported to be associated with endodontic infections (21) and to the diversity in carious dentine seen by using a combination of culture-based and cloning techniques (20), but greater than the level of diversity determined in previous carious dentine studies with only culture-based methods (1,7,11).…”

Section: Discussionsupporting

confidence: 71%

Molecular Analysis of Microbial Diversity in Advanced Caries

et al. 2005

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Real-time PCR analysis of the total bacterial load in advanced carious lesions has shown that the total load exceeds the number of cultivable bacteria. This suggests that an unresolved complexity exists in bacteria associated with advanced caries. In this report, the profile of the microflora of carious dentine was explored by using DNA extracted from 10 lesions selected on the basis of comparable total microbial load and on the relative abundance of Prevotella spp. Using universal primers for the 16S rRNA gene, PCR amplicons were cloned, and approximately 100 transformants were processed for each lesion. Phylogenetic analysis of 942 edited sequences demonstrated the presence of 75 species or phylotypes in the 10 carious lesions. Up to 31 taxa were represented in each sample. A diverse array of lactobacilli were found to comprise 50% of the species, with prevotellae also abundant, comprising 15% of the species. Other taxa present in a number of lesions or occurring with high abundance included Selenomonas spp., Dialister spp., Fusobacterium nucleatum, Eubacterium spp., members of the Lachnospiraceae family, Olsenella spp., Bifidobacterium spp., Propionibacterium sp., and Pseudoramibacter alactolyticus. The mechanisms by which such diverse patterns of bacteria extend carious lesions, including the aspect of infection of the vital dental pulp, remain unclear.

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“…As the lesion progresses, there is a transition from predominantly facultative gram-positive bacteria in early caries to anaerobic gram-positive rods and cocci and gram-negative rods in deep carious lesions (15). Previous research has associated the presence of anaerobic gram-negative rods, such as Fusobacterium, Prevotella, and Porphyromonas, with symptomatic teeth (11,19), infected pulps (38), and periapical abscesses (29,35), whereas anaerobic gram-positive cocci, such as peptostreptococci, have been associated with apical infections (10).…”

mentioning

confidence: 99%

Quantitative Microbiological Study of Human Carious Dentine by Culture and Real-Time PCR: Association of Anaerobes with Histopathological Changes in Chronic Pulpitis

et al. 2002

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The bacteria found in carious dentine were correlated with the tissue response of the dental pulps of 65 teeth extracted from patients with advanced caries and pulpitis. Standardized homogenates of carious dentine were plated onto selective and nonselective media under anaerobic and microaerophilic conditions. In addition, real-time PCR was used to quantify the recovery of anaerobic bacteria. Primers and fluorogenic probes were designed to detect the total anaerobic microbial load, the genera Prevotella and Fusobacterium, and the species Prevotella melaninogenica, Porphyromonas endodontalis, Porphyromonas gingivalis, and Micromonas (formerly Peptostreptococcus) micros. The pulpal pathology was categorized according to the cellular response and degenerative changes. Analysis of cultured bacteria showed a predominance of gram-positive microorganisms, particularly lactobacilli. Gram-negative bacteria were also present in significant numbers with Prevotella spp., the most numerous anaerobic group cultured. Real-time PCR analysis indicated a greater microbial load than that determined by colony counting. The total number of anaerobes detected was 41-fold greater by real-time PCR than by colony counting, while the numbers of Prevotella and Fusobacterium spp. detected were 82-and 2.4-fold greater by real-time PCR than by colony counting, respectively. Real-time PCR also identified M. micros, P. endodontalis, and P. gingivalis in 71, 60, and 52% of carious samples, respectively. Correlation matrices of the real-time PCR data revealed significant positive associations between M. micros and P. endodontalis detection and inflammatory degeneration of pulpal tissues. These anaerobes have been strongly implicated in endodontic infections that occur as sequelae to carious pulpitis. Accordingly, the data suggest that the presence of high levels of these bacteria in carious lesions may be indicative of irreversible pulpal pathology.The microbial populations involved in dental caries are known to be highly complex and variable and have not yet been fully identified, although key organisms are generally recognized to be associated with disease progression. The bacteria involved in caries initiation and early caries development, particularly the mutans group streptococci and lactobacilli, have been well documented (34). As the lesion progresses, there is a transition from predominantly facultative gram-positive bacteria in early caries to anaerobic gram-positive rods and cocci and gram-negative rods in deep carious lesions (15). Previous research has associated the presence of anaerobic gram-negative rods, such as Fusobacterium, Prevotella, and Porphyromonas, with symptomatic teeth (11, 19), infected pulps (38), and periapical abscesses (29, 35), whereas anaerobic gram-positive cocci, such as peptostreptococci, have been associated with apical infections (10).While it is well recognized that bacteria and their products play a major role in dental caries and associated pulpal inflammation (5), attempts to correlate clinical signs an...

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Microbiological studies of carious dentine from human teeth with irreversible pulpitis

Cited by 113 publications

References 39 publications

TGF-β1 Inhibits TLR-mediated Odontoblast Responses to Oral Bacteria

TGF-β1 Inhibits TLR-mediated Odontoblast Responses to Oral Bacteria

Molecular Analysis of Microbial Diversity in Advanced Caries

Quantitative Microbiological Study of Human Carious Dentine by Culture and Real-Time PCR: Association of Anaerobes with Histopathological Changes in Chronic Pulpitis

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