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2 periodontal dressings, Coe-pak and RD8 (a product under development), were assessed following periodontal surgery, using a double-blind study of randomised split-mouth design, with each patient acting as their own control. Matched sites were selected for periodontal flap surgery under local analgesia. Sites were randomly allocated to each group. The dressings were applied by a single operator and both patients and clinical assessors were blind as to the dressing employed. The dressings were assessed as to their handling properties, in addition to a 7-day post-operative assessment of the surgical sites and a subjective patient report. Maximum pain levels were relatively low (4 in a scale 0-10); subjects reported more pain and analgesics required with RD8 than with Coe-pak. This was reflected in the results of the patient assessment which indicated that 50% preferred Coe-pak, compared to 25% who preferred the RD8 dressing. The results showed RD8 to be an acceptable periodontal dressing when compared to Coe-pak. There were no statistically significant differences between treated sites in both groups with regard to post-operative plaque scores, bleeding scores or tissue healing.

Three types of irrigant, 2.6 per cent sodium hypochlorite, water and Solvidont were compared for their ability to remove debris during root canal preparation with ultrasonically operated K files. Twenty-seven freshly extracted human teeth were divided into three groups, and each group prepared using one of the irrigants. The teeth were sectioned longitudinally, stained and photographed for assessment by a ranking system. Canals prepared with sodium hypochlorite were found to have significantly less debris remaining than those prepared with water or Solvidont. No significant difference was found between preparations with water and Solvidont.

The accuracy of endodontic working length estimation was investigated using three imaging techniques: radiography (Rd), Xeroradiography (Xr) and Radiovisiography (RVG positive and negative prints). An in-vitro model of extracted single straight roots, mounted in wooden blocks with wax, was employed in the study. Optimum exposures were established for each of the imaging techniques. The magnification of the images was measured and the resolution of the RVG images was also investigated. Comparable Rd (D-speed film), Xr,RVG positive and RVG negative images were made of five roots with size 10 files in situ. Images of 10 standard files were made, ranging from 2.0 mm through the root apex to 2.5 mm short of the apex, resulting in 200 images. Six observers each assessed the working distance on 100 images, measuring the distance from the apical foramen to the file tip. After allowing for the magnification of the images, these results were compared with the 'true' file tip to apical foramen (measured with the aid of a reflex microscope). The inaccuracy of working distance estimations was considered to be of clinical significance (> 0.5 mm) in 6% of measurements made from Rd and Xr, 19.2% of measurements from RVG negative and 32.3% from RVG positive images. In addition, 14% of RVG images were too poorly defined to be assessed. The first-generation RVG system was used in this study. It was therefore concluded that the most accurate estimates of working distance were made from Xr and Rd images, and that RVG images, particularly the RVG positive images, were the least accurate and most difficult to read.(ABSTRACT TRUNCATED AT 250 WORDS)

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