Loss of attachment adjacent to class II carious lesions

The present study was designed to investigate the relationship between large open class II carious lesions and loss of periodontal attachment in 224 extracted teeth. Each tooth had a carious and a sound approximal surface. The teeth were divided into 4 groups: upper premolars, upper molars, lower premolars and lower molars each consisting of 56 teeth. Within each group, the carious lesions were divided equally between the mesial and distal surfaces. The teeth were stained and loss of attachment was measured under a stereomicroscope fitted with an ocularmicrometer. The difference in loss of attachment between carious (0.79 +/- 0.05 mm) and sound (0.76 +/- 0.04 mm) surfaces was not statistically significant. Loss of attachment was greater on the carious surface of 98 teeth, equal to in 40 teeth and less in 86 teeth than the sound surface. Mesial and distal surfaces with and without carious lesions exhibited essentially the same degree of loss of periodontal support. Upper molars and lower premolars tended towards more loss of attachment when compared with upper premolars and lower molars. The results indicate that large open class II carious lesions cannot be regarded as an important factor in the progression of attachment loss.