Open Access Research article

Improved ability of biological and previous caries multimarkers to predict caries disease as revealed by multivariate PLS modelling

Åke Nordlund1, Ingegerd Johansson1, Carina Källestål12, Thorild Ericson1, Michael Sjöström3 and Nicklas Strömberg1*

Author Affiliations

1 Department of Odontology/Cariology, Umeå University, 901 87 Umeå, Sweden

2 Department of Women's and Children's Health/International Maternal and Child Health, Uppsala University, 751 85 Uppsala, Sweden

3 Department of Chemistry, Umeå University, 901 87 Umeå, Sweden

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BMC Oral Health 2009, 9:28  doi:10.1186/1472-6831-9-28

Published: 3 November 2009



Dental caries is a chronic disease with plaque bacteria, diet and saliva modifying disease activity. Here we have used the PLS method to evaluate a multiplicity of such biological variables (n = 88) for ability to predict caries in a cross-sectional (baseline caries) and prospective (2-year caries development) setting.


Multivariate PLS modelling was used to associate the many biological variables with caries recorded in thirty 14-year-old children by measuring the numbers of incipient and manifest caries lesions at all surfaces.


A wide but shallow gliding scale of one fifth caries promoting or protecting, and four fifths non-influential, variables occurred. The influential markers behaved in the order of plaque bacteria > diet > saliva, with previously known plaque bacteria/diet markers and a set of new protective diet markers. A differential variable patterning appeared for new versus progressing lesions. The influential biological multimarkers (n = 18) predicted baseline caries better (ROC area 0.96) than five markers (0.92) and a single lactobacilli marker (0.7) with sensitivity/specificity of 1.87, 1.78 and 1.13 at 1/3 of the subjects diagnosed sick, respectively. Moreover, biological multimarkers (n = 18) explained 2-year caries increment slightly better than reported before but predicted it poorly (ROC area 0.76). By contrast, multimarkers based on previous caries predicted alone (ROC area 0.88), or together with biological multimarkers (0.94), increment well with a sensitivity/specificity of 1.74 at 1/3 of the subjects diagnosed sick.


Multimarkers behave better than single-to-five markers but future multimarker strategies will require systematic searches for improved saliva and plaque bacteria markers.