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Notes: Abstract Bacterial specificity in human periodontal diseases suggests the possibility of diagnosing and treating periodontitis as specific infections and using microbiological diagnostic means to evaluate the efficacy of periodontal therapy. In a series of clinical trials, the usefulness of topical antimicrobial agents in combination with surgical and non-surgical conventional periodontal therapy were tested. The healing result was estimated by monitoring probing attachment levels (PAL). The usefulness of clinical and microbiological parameters to evaluate post-treatment healing result was tested. 9 of the patients exhibiting sites with recurrent periodontal disease were then evaluated for clinical and microbiological parameters to define accurate means to differentiate between active and inactive periodontal disease. The results showed that the frequency of periodontal lesions with significant loss of PAL after treatment was less in patients treated with antimicrobial agent. Specific microbiological parameters showed stronger correlation than clinical parameters with gain and/or loss of PAL post-treatment. Thus Actinobacillus actinomycetemcomitans and Bacteroides gingivalis occurred in periodontal lesions with progressing disease after treatment, but were rarely detected in samples from pockets of the same depths which did not exhibit further loss of PAL over a study period of 1 year. This study points to the usefulness of topical antimicrobial agent as an adjunct to mechanical subgingival debridement in the treatment of periodontitis in adults. The results also indicate the utility of diagnostic microbiology in the assessment of periodontal disease activity post-treatment.

Notes: Experimental diabetes in the rat rapidly produces a shift in the gingival crevicular microflora which is followed, within weeks, by increased production of collagenase by the gingival tissues. To assess the contribution of endogenous (hormonal or metabolic) and exogenous (altered crevicular microflora) factors on this diabetes-induced abnormality in collagenase production, the following series of experiments was undertaken: In each experiment, the germfree rats were housed in two isolators. Half of the animals in both isolators were rendered diabetic (D) with streptozotocin while the remainder were left untreated (non-diabetic (ND) controls). All of the germfree ND and D rats in one isolator of the pair were then infected with either a Gram-positive (S. mitis or A. odontolyticus) or a Gram-negative (Capnocytophaga, A. aclmomycetemcomitans or B. gingivalis) organism. In the other isolator, the ND and D rats were maintained in their germfree state. After 3 wk, the germfree and monoinfected rats were killed and the gingiva (and in one experiment, skin) were dissected. Collagenase activity produced by gingiva in culture (or extracted from gingiva or from skin) was measured using 14C-collagen fibrils (or [3Hmethyl] collagen molecules) as the substrate. Diabetes increased the collagenolytic activity in the gingiva and skin of the germfree rats. Infecting the germfree rats with a Gram-positive organism had no effect on collagenase activity generated by the gingival explants in the tissue culture system. In contrast, infection with any of the Gram-negative organisms dramatically increased the collagenase activity in the gingival tissues of the ND rats in culture, an effect not seen in the D group of rats using this system. However, monoinfection with B. gingivalis did increase collagenase activity in the extracts of gingiva (but not in skin) from both ND and D rats, with the latter group showing the highest level of enzyme activity. We suggest (i) that experimental diabetes stimulates collagenase production in gingiva by both endogenous (hormonal) and exogenous (bacterial) mechanisms, and (ii) that crevicular Gram-negative organisms stimulate collagenolysis in the adjacent gingival tissues by releasing bacterial products (e.g. endotoxins) which penetrate into the connective tissue and enhance host cell collagenase production.

Notes: Localized juvenile periodontitis (LJP) is characterized by severe, early onset alveolar bone loss, localized to the first molars and incisors and a high prevalence of infection with Actinobacillus actinomycetemcomitans and associated neutrophil functional abnormalities. Due to the frequent occurrence of this condition in families, it was the purpose of this investigation to determine the association of neutrophil chemotaxis abnormalities and clinical periodontal disease in families with LJP. Twenty-two families were studied in which the proband was selected based upon presentation of LJP. All siblings were examined for the presence of LJP and neutrophil chemotaxis was measured on all subjects. The results indicate that there is a high association of LJP and neutrophil chemotaxis disorders and that this association is consistent along family lines. Specially, in families in which the proband exhibits a neutrophil chemotaxis disorder, all affected siblings (LJP) also exhibit depressed neutrophil chemotaxis, whereas, non-affected siblings beyond the age of puberty have normal neutrophil chemotaxis. On the other hand, in families where the proband (LJP) exhibits normal chemotaxis, both normal and affected siblings exhibit normal chemotaxis. The finding among families with LJP that some exhibit neutrophil chemotactic depression and others exhibit normal neutrophils suggests heterogeneity of LJP. Accordingly, it is proposed that there is a syndrome of familial localized juvenile periodontitis with depressed neutrophil chemotaxis and another form of familial localized juvenile periodontitis with normal neutrophil chemotaxis. The chemotaxis disorder and LJP occur in nearly one-half of the siblings in families with LJP. which is consistent with a dominant trait. however, multigenerational studies are necessary to determine the mode of inheritance. Hence, neutrophil chemotaxis is a disease marker which can be used in genetic studies of familial LJP with depressed neutrophil chemotaxis. Furthermore, prepubertal siblings often exhibit defective neutrophil chemotaxis in the families in which the proband exhibits such a defect. Since the prepubertal siblings are not affected by clinically detectable LJP, the finding of neutrophil chemotactic depression in these children further suggests that the neutrophil chemotactic defect is genetic in origin, precedes and may predispose to localized juvenile periodontitis.

Notes: A sonic extract of Actinobarillus actinomycetemcomitans Y4, a microorganism originally isolated from a patient with juvenile periodontitis, contains a leukotoxin (Aa-leukotoxin) which specifically kills human polymorphonuclear leukocytes (PMNs) and monocytes. In the presence of normal human sera, the toxicity of the leukotoxin is enhanced, whereas sera from patients with juvenile periodontitis neutralize leukotoxic activity. In juvenile penodontitis serum immunoglobulin G was identified as the specific inhibitor of the Aaleukotoxin. The leukotoxin enhancing factor(s) in normal human serum appeared to be a large molecular weight protein which was not immunoglobulin. Pooled sera from rabbits immunized with A. actinomycetemcomitans Y4 sonic extract also neutralized Aaleukotoxic activity while normal rabbit serum enhanced toxicity. The presence of antileukotoxin antibody in sera from individuals with juvenile periodontilis suggests that these people have been immunized with A. actittotnyCetemeomitans microorganisms. Monitoring of this antibody may be a convenient tool in the study of the etiology of juvenile periodontitis.

Notes: The ability of fresh isolates of B. gingivalis to establish abscesses in the mouse model was studied by comparing them with established laboratory strains of B. gingivalis. Eight fresh isolates obtained from plaque associated with periodontal disease and grown under similar conditions as established strains were injected subcutaneously on the back of the mouse. All of these strains produced secondary lesions on the abdomen. Septicemia was associated with seven of the strains. Two commonly used laboratory strains, W50 and W83, also produced secondary lesions and septicemia. Five other laboratory strains produced only localized abscesses. On histologic examination, the strains that produced disseminated disease showed invasion of connective disease by individual bacteria that were not in clumps. The strains that produced localized abscesses were characterized by growing in colonies or clumps in the abscess cavity. Four synthetic enzyme substrates were examined to determine whether the differences between invasive and non-invasive strains were due to differences in proteolytic enzyme production. No differences in enzyme production could be demonstrated with the selected substrates.

Notes: Bacteroides gingivalis produces large amounts of proteolytic enzymes which may play a role in its virulence. These enzymes may participate in the tissue destruction of the inflammatory process. In this study, the characteristics of two such enzymes, N-CBz-glycyl-glycyl-arginyl peptidase (N-CBz-Gly-Gly-Arg peptidase) and glycyl-prolyl peptidase (Gly-Pro peptidase) were investigated. The enzymes eluted in different peaks from an anion exchange column. N-CBz-Gly-Gly-Arg peptidase was associated with cells up to 48 h in culture. If cultured longer, it also released in the supernatant. It exhibited optimal activity between pH of 7.0 and 7.5 and was readily inactivated by heat treatment (45°C for 15 min). The enzyme activity was inhibited by p-chloromercuribenzoic acid (PCMB), leupeptin and antipain, suggesting that it is a thiol protease. The B. gingivalis N-CBz-Gly-Gly-Arg peptidase was different from the serum enzyme that digests the same substrate. The serum enzyme was more resistant to heat treatment and was inhibited by diisopro-pylfluorophosphate (DFP). B. gingivalis also produced Gly-Pro peptidase that is released in the supernatant. The enzyme has an optimal pH range between 7.5 and 8.0. The B. gingivalis Gly-Pro peptidase was inhibited by DFP, suggesting that it represents a serine protease. The serum Gly-Pro peptidase did not differ from the bacterial enzyme with respect to its sensitivity to inhibitors; however, they were markedly different in heat sensitivity. The bacterial enzyme was completely inactivated at 60°C for 30 min, whereas the serum enzyme was not inactivated even at 1 h at 60°C.

Notes: Several cationic, mixed and amphoteric surfactants were tested for their antimicrobial activity and ability to inhibit the formation of in vitro plaque by oral microorganisms. All had antimicrobial activity against Actinomyces viscosus. Actinomyces naeslundii and Streptococcus mutans. Cationic surfactants were comparable to chlorhexidine in antimicrobial activity but were less effective in inhibiting plaque formation. Amphoteric surfactants were less effective than other detergents in antibacterial activity and had very limited capacity for the inhibition of plaque formation. Comparison of drug structure provides evidence that surfactant substantivity to saliva-coated enamel is a cation active process. Saliva was found to have an antagonistic effect on the activity of cetylpyridinium chloride but not on Triburon.

Notes: Utilizing intraoral radiographs of human skulls taken at known vertical angulation, we have demonstrated that expression of the crest level as a distance between cej and the crest is as accurate as a ratio of bone height to root length. The degree of inaccuracy of either of these measures is related to the magnitude of the angular deviation of the x-ray beam from 90°. Angular deviation can be estimated from calculation of a cusp height score (ratio of lingual cusp height to buccal cusp height × 100). Based on the analysis of cusp height scores it was determined that the x-ray beam angulation for posterior bitewings ranged between 90° and 80° whereas for posterior periapicals the angulation range was between 90° and 70° Therefore, it is recommended that, for longitudinal studies of bone height, measurements of the crest to cej distance, particularly in the region of the molars, be made utilizing bitewing radiographs. For the premolar and incisor regions, deviation of the vertical angulation of an x-ray of up to 20° from a 90° baseline resulted in little, if any, change in crest level by either one of the two measures used. An appendix is provided for the theoretical modeling of the types and magnitude of change in crest level observed for projection images of different anatomical configurations.