Extension of the carious lesion into the matrix of dentine undermines the physical and functional integrity of the tooth and provides an increasingly noxious insult to the underlying pulp tissue. The bacteria associated with this process are not well understood. Currently, there are no reliable means of identifying the status of the pulp tissue underlying a carious lesion and no enhanced therapeutic modalities are available. This seriously impairs the efficacy of current diagnostic and treatment regimes for this clinically important disease. ? ? Preliminary studies have used a universal bacterial amplicon based on 16S rDNA to define the major bacterial populations of carious dentine. This work was complemented by real-time polymerase chain reaction quantification of bacterial DMA to determine levels of bacterial species identified by phylogenetic analysis. A complex array of predominantly anaerobic bacteria was demonstrated with characteristic Lactobacillus and Prevotella spp. dominant. Further dissection of the microbial composition of the developing lesion will be enhanced by development of methods for enriching the display in population analysis of low abundance species of interest. The sequence information obtained will be used to design specific oligonucleotide probes for the determination of the spatial localization of organisms within the lesion by fluorescence in situ hybridization combined with confocal microscopy. ? ? Experimental analysis will extend to provide information on the mechanisms of bacterial invasion of the Dental pulp at high resolution using both extractive and in situ approaches and relate this to the histopathological responses of the pulps. Data obtained from this study will provide an objective basis for an understanding of the extension of the carious process with potential diagnostic value for predicting pulp response including pulpal death and endodontic infection. ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
Research Project (R01)
Project #
5R01DE015272-04
Application #
7413635
Study Section
Oral, Dental and Craniofacial Sciences Study Section (ODCS)
Program Officer
Lunsford, Dwayne
Project Start
2005-08-29
Project End
2009-03-31
Budget Start
2008-04-01
Budget End
2009-03-31
Support Year
4
Fiscal Year
2008
Total Cost
$200,445
Indirect Cost
Name
U.S. Nat'L Inst/Dental/Craniofacial Res
Department
Type
DUNS #
214591549
City
Sydney
State
Country
Australia
Zip Code
2145
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Kianoush, Nima; Nguyen, Ky-Anh T; Browne, Gina V et al. (2014) pH gradient and distribution of streptococci, lactobacilli, prevotellae, and fusobacteria in carious dentine. Clin Oral Investig 18:659-69
Charadram, Nattida; Austin, Christine; Trimby, Patrick et al. (2013) Structural analysis of reactionary dentin formed in response to polymicrobial invasion. J Struct Biol 181:207-22
Charadram, Nattida; Farahani, Ramin M; Harty, Derek et al. (2012) Regulation of reactionary dentin formation by odontoblasts in response to polymicrobial invasion of dentin matrix. Bone 50:265-75
Farahani, Ramin M; Sarrafpour, Babak; Simonian, Mary et al. (2012) Directed glia-assisted angiogenesis in a mature neurosensory structure: pericytes mediate an adaptive response in human dental pulp that maintains blood-barrier function. J Comp Neurol 520:3803-26
Farahani, Ramin M; Simonian, Mary; Hunter, Neil (2011) Blueprint of an ancestral neurosensory organ revealed in glial networks in human dental pulp. J Comp Neurol 519:3306-26
Zou, W; Hunter, N; Swain, M V (2011) Application of polychromatic µCT for mineral density determination. J Dent Res 90:18-30
Nadkarni, Mangala A; Simonian, Mary R; Harty, Derek W S et al. (2010) Lactobacilli are prominent in the initial stages of polymicrobial infection of dental pulp. J Clin Microbiol 48:1732-40
Farahani, Ramin M; Nguyen, Ky-Anh; Simonian, Mary et al. (2010) Adaptive calcified matrix response of dental pulp to bacterial invasion is associated with establishment of a network of glial fibrillary acidic protein+/glutamine synthetase+ cells. Am J Pathol 177:1901-14
Zou, Wei; Gao, Jinlong; Jones, Allen S et al. (2009) Characterization of a novel calibration method for mineral density determination of dentine by X-ray micro-tomography. Analyst 134:72-9

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