A clinical and microbiological study of approximal carious lesions. Part 1: the relationship between cavitation, radiographic lesion depth, the site-specific gingival index and the level of infection of the dentine.

A clinical study was carried out to assess relationship between the presence of approximal cavitation, the radiographic depth of the lesion, the site-specific gingival index and the level of infection of the dentine. Adult patients assessed as needing operative treatment and presenting with approximal lesions visible in the outer third of dentine on bite-wing radiographs were included in the study. Direct lesion depth measurements were recorded from the radiographs and the site-specific gingival index adjacent to the lesion was noted. The presence or absence of a cavity was recorded on an impression following tooth separation. During operative treatment samples of dentine were taken on entry to the lesions to ascertain the level of infection of the dentine. Visual evaluation of 54 successfully recorded impressions revealed that 85% were cavitated. Cavitated lesions were found to have higher site-specific gingival index scores compared to non-cavitated lesions (p = 0.03). The probability of cavitation was greater for lesions >0.5 mm from the enamel-dentine junction on bite-wing radiographs (p<0.01). The level of infection of the dentine was significantly higher for cavitated lesions than for non-cavitated lesions (p = 0.02). However, the non-cavitated lesions were still infected.