Crevicular fluid myeloperoxidase at healthy, gingivitis and periodontitis sites

The volume and myeloperoxidase (MPO) activity of gingival crevicular fluid (GCF) collected with filter paper strips for 30 s from the sulcus of healthy, gingivitis and periodontitis sites of Chinese subjects were measured. MPO/site and MPO/microliter GCF were both greater at gingivitis and periodontitis sites than at healthy sites. Enzyme activity was similar at the 2 categories of diseased sites. Mean GCF volume and MPO activity were calculated for all samples from healthy, gingivitis and periodontitis sites with GI 0, 1, 2 and 0 + 1. GCF volume, MPO/site and MPO/microliter GCF all were greater at GI 2 than GI 0 or 0 + 1. These data indicate that increased GCF MPO previously observed at periodontitis sites is not specific to such sites. Rather increased GCF MPO likely occurs when additional polymorphonuclear leukocytes enter the sulcus as a result of gingival inflammation. A second sample was obtained from 22 sites 4 weeks after the initial collection. These samples were collected for 5 s rather than 30 s. The GCF volume, MPO/site and MPO/microliters GCF were each greater in samples collected for 30 s rather than 5 s. Correlation coefficients showed that the amount of GCF and MPO activity of the fluid collected for 5 s and 30 s was dependent upon the site even though the 5-s and 30-s samples were collected 4 weeks apart.     

The use of DNA probes to examine the distribution of subgingival species in subjects with different levels of periodontal destruction

The present investigation examined the distribution of 14 subgingival species at a total of 2299 sites in 90 subjects with different levels of periodontal destruction. Subgingival plaque samples taken from the mesial aspect of each tooth were anaerobically dispersed, diluted and plated on non selective media. After anaerobic incubation, colonies were lifted to nylon filters and specific species detected using digoxygenin-labeled whole chromosomal DNA probes. The mean total viable count for all sites in all subjects was 8.3 x 10(6). The probes accounted for an average of 27.8% of the total viable count. The % of subjects in which each species was detected was as follows; V. parvula, 98; B. intermedius I, 98; S. sanguis II, 96; B. intermedius II, 95; C. ochracea, 94; B. gingivalis, 91; S. sanguis I, 85; W. recta, 83; F. nucleatum ss. vincentii, 82; S. intermedius, 80; B. forsythus, 76; P. micros, 74; A. actinomycetemcomitans serotype a, 62 and A. actinomycetemcomitans serotype b, 52. The % of sites colonized by each of the 14 test species varied considerably within different subjects. The median number of sites colonized by different species ranged from 3.6% for A. actinomycetemcomitans serotype b to 43.5% for V. parvula. In half the subjects, the mean % of the total viable counts for each of the test species was less than 4%. When subjects were divided on the basis of % of sites at baseline with greater than 3 mm attachment loss, the 14 probes accounted for 29.9% of the microbiota in the localized disease group and 25% in the widespread disease group.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effects of phenytoin and sodium valproate on the periodontal health of adult epileptic patients

The periodontal health of 30 adult epileptic patients treated with either sodium valproate or phenytoin was compared with a control group (n = 15) of otherwise healthy patients. The 3 groups were matched for age and sex. Patients on phenytoin therapy showed significantly higher plaque scores (P less than 0.05), gingival index (P less than 0.05) and pocketing (P less than 0.05) than patients in the control group. The % of gingival hyperplasia was significantly higher (P less than 0.05) in the phenytoin-treated patients than those on sodium valproate or in the control group. However, patients on phenytoin therapy had significantly less bone loss than those on sodium valproate (P less than 0.05) or in the control group (P less than 0.01). No significant differences were observed between the sodium valproate group and the control group on any of the parameters assessed. The results from this study would suggest that sodium valproate has no unwanted effects on periodontal health and may be considered a safe alternative, regarding the periodontal aspects, to phenytoin for the treatment of adult onset epilepsy.     

Microstructure and strength properties of silicate and glass ionomer cements

Microstructure characterization of silicate and glass ionomer cements has been carried out using, SEM, EDAX and ion microprobe techniques. The distribution of aluminum, calcium, fluorine, phosphorus or silicon was measured in the set cement surfaces. Cracks in the cement specimens produced by mechanical breaking, in contraction during setting, or as a result of SEM preparation were observed to occur mainly in the matrix and in the interface between matrix and particle. Powders of silicate and glass ionomer cements were separated into various fractions using sieves or cyclone separation technique. Compressive strength measurements of specimens made of powders with various size distributions have been assessed. The fractionation did not reveal any strong effect on the compressive strength properties either for the silicate or the glass ionomer cement.     

Distribution of the EDTA-soluble non-collagenous organic matrix components of rabbit incisor dentine

EDTA-soluble fractions were obtained from serial sections of rabbit incisor dentine. The amounts of protein in each extract were measured and their amino acid composition determined. Changes in composition and amount of protein were found and 3 zones could be differentiated. Zone 1, from the immature end of the root to approx. $\text{1}\text{3rd}$ of the way along the incisor, contained low levels of protein, predominantly of the anionic glycoprotein type. Zone 2, from zone 1 to approx. $\text{1}\text{2}$ way along the incisor near an opaque boundary, contained higher levels of protein with a much greater proportion of the less-acidic glycoproteins. The 3rd zone, from zone 2 to the incisive edge, appeared to consist of a mixture of non-collagenous matrix protein together with further protein material, possibly of pulpal origin.