In order to examine the relationship of possible crevicular biochemical parameters to attachment loss (ALOSS), 330 sites from 8 untreated adult patients were monitored longitudinally at 3-month intervals, for up to 1 year. Attachment levels were measured with a force-sensing probe and an acrylic stent in duplicates at each study point. Crevicular samples were collected and used for the determination of the following 11 markers: number of polymorphonuclear leukocytes (PMNs), prostaglandin E2 (PGE2), osteocalcin (OC), alkaline phosphatase (ALP), collagenase (COL), beta-glucuronidase (BG), antigenic and functional elastase (AEL and FEL), alpha-1 antitrypsin (a1AT), alpha-2 macroglobulin (a2M) and aspartate aminotransferase (AST). 10 sites with ALOSS of > or = 1.5 mm per 3 months (active sites) and 43 sites with negligible changes (inactive sites) were identified. Total amounts of ALP, BG and COL were found to be significantly higher in active as compared to inactive sites, prior to significant ALOSS, without any significant differences in crevicular fluid volume and clinical indices. When biochemical parameters were expressed as ratios to the number of PMNs, PGE2/ PMNs was significantly elevated in active sites. The capacity of such individual parameters to distinguish between active and inactive sites was limited. However, linear discriminant analysis using total amounts of PGE2, COL, ALP, a2M, OC and AEL showed more significant diagnostic values (sensitivity: 80%, specificity: 91%). These findings suggest that the combination of several biochemical parameters in crevicular fluid could give more information to predict future clinical ALOSS.

Ten interproximal sites, with periodontal pockets deeper than 5 mm and showing loss of bone on standard dental radiographs, were treated by subgingival instrumentation in 10 patients properly motivated and given thorough hygiene instructions. The index of gingival inflammation, the plaque index, the degree of mobility, the depth of the pockets, and the loss of attachment were measured before starting the treatment, and 2 months, 6 months, and 1 year after treatment. Standardized reproducible radiographs of the 10 sites were taken by using a recently developed paralleling instrument before treatment, immediately after and 2 months, 6 months, and 1 year afterwards. The density of the interdental bone was measured on the radiographs by a computer assisted densitometric technique at three levels of the interdental septum: the most occlusal or "superficial" level; the "deep" level, arbitrarily chosen 1.5 mm below; and the "control" level, in a much deeper area of interproximal bone. As further control, the density of the superficial crestal bone was also followed in 5 healthy untreated sites from 5 of the patients. As expected, a significant improvement of the clinical parameters was observed during the year following therapy. The results of the radiographical analysis showed statistically significant increases of both the superficial and deep average densities of interproximal bone at 6 months and 1 year after treatment. The superficial bone density was, on the average, 13% higher at 6 months and 16% higher at 1 year, as compared to that measured immediately after treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

12 buccal or lingual class II furcation lesions were selected in the lower molars of 7 patients after treatment by routine scaling. In each of the 7 patients, 1 lesion was treated by guided tissue regeneration (GTR) with expanded polytetrafluoroethylene membranes, while 5 neighbouring molars underwent conventional flap operations. The index of gingival inflammation, the plaque index, the depths of the pockets, the horizontal and vertical attachment levels were measured before and 6 months, 1 year and 2 years after surgery. Standardized reproducible radiographs were taken before treatment, post-operatively (at the time of membrane removal for the GTR treated sites), at 6 months, 1 year and 2 years after treatment. The density of bone was quantified in several areas by using high-resolution digital analysis. With the exception of the higher gain in horizontal attachment observed in the GTR treated furcations, the improvement of clinical parameters was similar in all sites during the 2 years of follow-up. The radiographical analysis showed no statistically significant changes neither in the GTR nor in the conventionally treated lesions over this period of time, even when they were compared to untreated bone control areas. However, in this study limited to 7 patients, the interdental bone next to the GTR treated furcations showed significant signs of remodeling.

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Photodensitometry is known to provide high spatial resolution and continuous measurement of optical density for the analysis of dental radiographs, whereas digitization allows powerful image manipulations but, when using conventional video cameras, gives less spatial resolution and fewer grey levels. The aim of this study was therefore to develop a technique of highresolution digital analysis for the measurement of bone density following the same principles as those of photodensitometry and based upon the use of a CCD Scanner Camera which provides up to 4096 grey levels and a spatial resolution of 4096 X 4096 pixels. Twenty-four zones were analysed with both techniques in five serial dental radiographs taken before and after periodontal therapy in eight patients. Statistical comparison of the results obtained by digital analysis and photodensitometry shows that the two techniques have the same accuracy.