An air-powder abrasive system was tested among 20 volunteers, who had healthy gingiva or slight gingivitis, but no periodontal pockets. Impressions of randomly selected areas (n = 103) were taken before and after airpolishing and positive replicas were prepared for scanning electron microscopy (SEM). Gingival bleeding increased statistically significantly (p less than 0.001) during the treatment. Also gingival erosive changes were increased when using airpolishing technique (p less than 0.001). The erosive changes observed by SEM and the subjective symptoms during and after the operation positively correlated to the presence of gingival inflammation (p less than 0.001). It can be concluded that also the negative aspects of the airpolishing technique should be taken into consideration, especially when operating near the gingival margin.

The effect of an air-powder abrasive system on dental hard tissues was tested on 20 volunteers. Impressions of 150 randomly selected areas were taken before and after airpolishing and positive replicas were prepared for scanning electron microscopic examination (SEM). The amount of dental plaque on tooth surfaces was reduced by the treatment (P less than 0.001). The abrasive changes caused by airpolishing on enamel were greater on the surfaces covered by dental plaque before the airpolishing compared to the surfaces without plaque (P less than 0.01). The enamel and cemental surfaces were more abraded after the treatment compared with the initial condition. Despite the effectiveness of the dental airpolishing technique, the negative aspects should be considered in the decision to use airpolishing in routine prophylaxis, especially in patients with root surfaces exposed to the oral cavity.

No abstract

Syrjanen SM, Alakuijala P, Markkanen SO, Markkanen H: Gingival fluid, betag-microglobulin and protein levels as indicators ofperiodontal disease. ScandJ Dent Res 1989; 97: 500^.Abstract -Pj-microglobulin (fJj-m), lysozyme and protein concentrations in gingival fluid were anah^ed in 19 patients with severe periodontitis and in 19 controls devoid of any clinical signs of inflammation. A significant increase of the total protein and P^-m levels was found in periodontal subjects. In contrast, lysozyme concentration did not reflect the indammatory status ofthe periodontium. Statistical analyses showed signi^cant correlations between p^-m and protein concentrations in both groups. Furthermore, the values obtained by Periotron 600 closely correlated with the protein and P^-m contents, indicating that this method is a reliable aid in assessment ofthe quantity and quality of crevicular exudate and thus the severity ofperiodontal disease.

A novel method is introduced for the estimation of grain numbers in autoradiographic sections of articular cartilage with an image analyzer. It is based on separation of grains from the underlying structures by gray level thresholding and determination of the percentage of total area occupied by grains in a relatively large measuring field. The mean grain size is used as a reference to calculate grain numbers per cell profile and per unit area of tissue in various zones of bovine articular cartilage labelled with 35S-sulphate in tissue culture. The results demonstrate considerable zonal differences as well as site related topographic variation in the rate of 35S-sulphate incorporation. The largest site-related variation in the grain counts was observed in the superficial zone, suggesting a delicate control of proteoglycan synthesis in this zone.