[Marginal fit of dental restorations and the periodontium in Swiss army recruits]. / Restaurationsrandschlusse und Parodont bei Schweizer Rekruten.

The present study analyzed the relationship between periodontal health adjacent to filled and unfilled tooth sites in young men (recruits). The status of oral health of 419 Swiss army recruits, aged 19 to 20 years was assessed by determining Plaque Index (PI), Retention Index (RI) and Gingival Index (GI) as well as Pocket Probing Depth (PPD) and Probing Attachment Loss (PAL). In addition, the level of alveolar bone was measured using digitized bite-wing radiographs with an enlargement of 4.5x. Filling margins were assessed and the distance between the alveolar bone crest and the cemento-enamel junction (CEJ) measured to the nearest one tenth of a millimeter. These data were compared with the clinical parameters. A total of 8'050 sites were examined. 765 or 9.5 of the sites in the posterior area were filled. 119 of them showed filling overhangs larger than 0.2 mm. Thus, 1.5 % of the examined sites had a significant overhanging margin. All clinical parameters had greater values at filled than at unfilled sites. The differences were statistically not significant. Even the sites with margins overhanging more than 0.8 mm (n=14) did not show significantly different parameters compared to unfilled sites. The comparison with a similar study involving recruits 11 years earlier assessed that the recruits of 1996 had less and smaller filling overhangs. This, in turn, means that, in Switzerland restorative dentistry in young males has been markedly improved during the 1980's and 1990's.

Automated short range locator system.

A computer operated system is described for determining the location of a subject fitted with a small sensing coil and telemetry transmitter. The system uses the geometric factors inherent in the value of the mutual inductance of a fixed and moveable coil. Results of a two-dimensional system are shown.