OPERATIVE AND MICROBIOLOGICAL VALIDATION OF VISUAL, RADIOGRAPHIC AND ELECTRONIC DIAGNOSIS OF OCCLUSAL CARIES IN NON-CAVITATED TEETH JUDGED TO BE IN NEED OF OPERATIVE CARE

The diagnosis of occlusal caries depends upon the correct identificati on of demineralised enamel and dentine. However, tissue demineralisati on precedes bacterial infection so that dentine may be demineralised b ut uninfected. The presence of a bacterial infection of dentine may be a more relevant factor to be considered when planning to restore a ca rious lesion. The aim of this clinical study was to validate three tec hniques for the diagnosis of occlusal caries as demineralised tissue a nd as infected demineralised tissue during cavity preparation. The stu dy sample was 82 non-cavitated occlusal lesions, judged by various den tists to be in need of operative care. The diagnostic techniques used by the single operator were vision, bitewing radiography and electroni c caries diagnosis. The validating techniques were a caries detector d ye to stain demineralised tissue, microbiological sampling to determin e the level of infection of the dentine and clinical assessment of the dentine at operation. The caries detector dye showed demineralised de ntine in 96% of the referred lesions. This demineralisation was reliab ly predicted by the electronic readings. However, the dentine samples from many teeth yielded only small numbers of bacteria indicating no, or only a very low level of bacterial infection. Neither vision nor el ectronic readings reliably predict heavily infected dentine. Radiograp hic evidence of dentine demineralisation was significantly associated with heavily infected dentine and this dentine was soft and wet at ope ration.