Zone between plaque and attached periodontal tissues on chronic periodontitis-affected teeth: an SEM study.

The zone between plaque and attached periodontal tissues on chronic periodontitis-affected teeth was examined by a combined macroscopic and scanning electron microscopy (SEM) approach. Examined were 27 teeth with chronic periodontitis (chronic periodontitis-affected group) and three healthy teeth with no evidence of periodontal disease (control group). Both groups were collected immediately after extraction, fixed in 2% glutaraldehyde, and post-fixed in 1% osmium tetroxide. Then, teeth were macroscopically examined to identify their stained zones. Teeth were dehydrated, critical-point dried, gold coated, and examined in an SEM. Both healthy and chronic periodontitis-affected teeth showed a very similar staining pattern on their surfaces. An unstained band with a belt-like appearance was observed around the teeth, delimited by two osmium-stained zones. Some weakly stained areas were frequently observed inside the unstained band. The SEM examination showed four different regions in both groups. These regions appeared in the following coronoapical sequence: dental plaque, plaque-free zone, junctional epithelium, and attached periodontal tissues. A dental cuticle covering the cementum surface from the plaque border to the junctional epithelium was detected on chronic periodontitis-affected teeth. Some aspects of this particular zone may be involved in the pathogenesis of inflammatory periodontal disease and therefore may have some influence on treatment for chronic periodontitis-affected teeth.