A simple paralleling instrument for superimposing radiographs of the molar regions.

A simple, disposable paralleling device to produce identical radiographs of the maxillary and mandibular molar regions is described. Its precision was determined by taking serial radiographs of several patients. No deformations were found when enlargements of the radiographs were made. Identical tracings were produced during analysis with a computer-assisted densitometric technique. The new device is inexpensive and could be used advantageously for qualitative and quantitative longitudinal studies.

Longitudinal quantitative radiodensitometric study of treated and untreated lower molar furcation involvements.

38 first or second lower molars from 16 patients showing furcation involvements of degrees 1 and 2 were treated after motivation and hygiene instruction, either by subgingival curettage, or by the modified Widman surgical procedure or by furcation plasty. The plaque index, the gingival index of inflammation and the depth of interproximal and interradicular pockets were recorded before and up to 1 year after the 3 therapeutical procedures. The above clinical indices were also followed for 2 years in 15 lower molars from 7 untreated patients. A quantitative radiographical analysis of the interradicular bone was performed in all patients, by using superposable identical radiographs and a computer-assisted photodensitometric technique. In the 3 groups of treated patients, the clinical scores were, in general, improved by the 3 therapeutic modalities. In the furcation areas, the plaque index was always higher on the lingual side, whereas the depth of "horizontal" pockets was always greater on the buccal side. Except for the lesions treated by furcation plasty, no change could be noticed clinically in the depths of vertical or horizontal penetration of a periodontal probe in the furcation areas. The quantitative radiographic analysis, however, clearly showed a loss in the first 2 mm of superficial bone during the 2 months following the 3 therapeutical procedures: this loss was followed by a statistically significant recovery and, for the group treated by curettage, even by a net gain during the 6 to 12 months following therapy. The radiographical density of the deeper layer of bone did not change in the group treated by curettage only. It showed a loss in the first 2 months following the 2 surgical procedures but a statistically significant recovery in the months thereafter. As for the group of untreated patients, at the examinations performed initially, 6 months, 1 and 2 years later, the number of plaque-free and non-bleeding sites in the furcation areas was lower on the lingual as compared to the buccal side, whereas the frequency distribution of furcation involvements was similar on both aspects. No significant changes were found in the various clinical parameters throughout the 2 years of the study. On the contrary, a significant loss of average density of the superficial layer of interradicular bone was already measured on the superposable radiographs 6 months after the initial examination and was found to increase thereafter. No changes of radiodensity could be measured for the deeper layer of bone.(ABSTRACT TRUNCATED AT 400 WORDS)

Densitometric analysis of lower molar interradicular areas in superposable radiographs.

Superposable radiographs of lower molar areas were obtained by means of a specially designed film holder and a gnathostat maintained in a constant position with respect to long-cone radiological equipement. A quantitative evaluation of the bone mass in the interradicular area was obtained by scanning the area under a photodensitometer. A photodensitometric scan of the image of an aluminium wedge adapted to each radiograph was also performed. This allowed the transformation, with the aid of a computer, of the photodensitometric recording of bone into a tracing of mm of aluminium equivalents. The reproducibility and precision of the method were verified by comparing magnifications of repeated radiographs, by photodensitometric readings of radiographs developed in different batches and by repeated quantitative readings of the same film. The method allowed one, for instance, to follow quantitatively the healing of a radiographically visible periapical lesion. It was also used to evaluate quantitatively, in the interradicular area, bone changes which could not be seen with the marked eye.

Periodontal status associated with chronic neutropenia.

A case of chronic neutropenia in a 12-year-old boy is reported. The patient presented with severe gingival inflammation and alveolar bone loss. Immunologic analysis of the patient's serum revealed the presence of precipitating antibodies against antigenic components of Actinobacillus actinomycetemcomitans Y4 and 652. It was also found that the serum neutralized the leukotoxic activity of Actinobacillus actinomycetemcomitans Y4. The etiology and the pathogenesis of periodontal disease in neutropenic patients are discussed in view of these findings.