Predictive Power of Different Clinical and Laboratory Caries Risk Parameters

Objectives: The aim of the study was to investigate the influence of preventive measures on caries risk evaluation. Methods: 150 caries free schoolchildren aged 8-9 were randomly selected for a preventive trial in three groups with quarterly application of varnishes containing fluoride (Duraphat®), chlorhexidine (Cervitec®) or a combination of F-Protector®/Cervitec®). 49 adolescents were re-investigated after 4.5 years; in both examinations caries (D3-4MFS) and initial caries (D1-2S) were recorded. At the end of the study the fluoride content of plaque and enamel and the bacterial load of the oral cavity were determined. Biopsy of enamel was carried out by filter discs with HClO4. Determination of calcium and fluoride by atomic adsorption and with the Orion electrode followed. Parallel plaque was sampled from three interdental spaces using dental floss. The amount of plaque was weighed, solubilised and analysed using the fluoride electrode. The intra-oral microbial challenge by mutans streptococci and lactobacilli was estimated by chairsite tests (Dentocult®) or by determination of lactic acid present in the oral cavity as most cariogenic final product of sugar metabolism. To this purpose there is a newly developed biochemical test Clinpro™-Cario-L-Pop™ (CCLP; 3M ESPE AG). Results: During the study period the caries prevalence increased up to 1.4–2.0 DMFS without any significant difference between groups. But the number of initial caries lesions raised significantly in the Duraphat group (DD1-2S=7.2) and differed from CHX+F combination group (DD1-2S=2.2). Microbial load estimated by different methods seemed to be equal and the F content of enamel (1024-745ppmF) was in reverse order to caries challenge recorded. But the fluoride concentration of dental plaque (0.4–1.7ppmF) agreed with the caries scores. Conclusions: Therefore, in summary it was concluded that individual oral hygiene which could reliably be checked by CCLP has more to be taken into consideration when evaluating caries trials.