Induced apoptosis of chondrocytes by Porphyromonas gingivalis as a possible pathway for cartilage loss in rheumatoid arthritis

The role of bacterial infections in the pathogenesis of rheumatoid arthritis (RA) has gained increasing interest. Patients with RA often exhibit periodontal disease, which is associated with pathogens like Porphyromonas gingivalis. The present study examines the direct effects of P. gingivalis on apoptosis of human chondrocytes (a feature of inflammatory joint diseases) as one can assume an interrelation of pathogenesis of RA and P. gingivalis infections. Primary chondrocytes were infected with P. gingivalis. Early apoptotic and dead cell analysis was performed using Annexin-V, 7AAD, and propidium iodide and examined by flow cytometry and fluorescence microscopy. Caspase activation and DNA fragmentation were determined by western blot analysis and TUNEL reaction. Flow cytometry and fluorescence microscopy demonstrated an increase of Annexin-V-positive early apoptotic chondrocytes after infection. Western blot showed upregulation of activated caspase-3 expression, and TUNEL reaction revealed considerable DNA fragmentation following infection. The data show that P. gingivalis promotes early and later stages of apoptosis of primary human chondrocytes, which might contribute to the joint damage seen in the pathogenesis of RA.

Regeneration of bone and periodontal ligament induced by recombinant amelogenin after periodontitis

Regeneration of mineralized tissues affected by chronic diseases comprises a major scientific and clinical challenge. Periodontitis, one such prevalent disease, involves destruction of the tooth-supporting tissues, alveolar bone, periodontal-ligament and cementum, often leading to tooth loss. In 1997, it became clear that, in addition to their function in enamel formation, the hydrophobic ectodermal enamel matrix proteins (EMPs) play a role in the regeneration of these periodontal tissues. The epithelial EMPs are a heterogeneous mixture of polypeptides encoded by several genes. It was not clear, however, which of these many EMPs induces the regeneration and what mechanisms are involved. Here we show that a single recombinant human amelogenin protein (rHAM⁺), induced in vivo regeneration of all tooth-supporting tissues after creation of experimental periodontitis in a dog model. To further understand the regeneration process, amelogenin expression was detected in normal and regenerating cells of the alveolar bone (osteocytes, osteoblasts and osteoclasts), periodontal ligament, cementum and in bone marrow stromal cells. Amelogenin expression was highest in areas of high bone turnover and activity. Further studies showed that during the first 2 weeks after application, rHAM⁺ induced, directly or indirectly, significant recruitment of mesenchymal progenitor cells, which later differentiated to form the regenerated periodontal tissues. The ability of a single protein to bring about regeneration of all periodontal tissues, in the correct spatio-temporal order, through recruitment of mesenchymal progenitor cells, could pave the way for development of new therapeutic devices for treatment of periodontal, bone and ligament diseases based on rHAM⁺.

Observations on a new collagen barrier membrane in 16 consecutively treated patients. Clinical and histological findings

BACKGROUND

Space-maintaining capacity, cell disclusive potential, and stability over time are crucial factors to achieving sufficient bone augmentation with membrane barriers. The case series presented here assessed a new collagen barrier used in bone augmentation. Clinically, the healing pattern, especially in cases of secondary healing, was studied.

METHODS

Soft tissue healing was documented by photographs, and the size of the dehiscences calculated by image analysis. The measurements were performed on digitized photographs. During reentry, barrier remnants were dissected and histologically evaluated.

RESULTS

The mean value for dehiscences was 35.5 mm2; all dehiscences healed within 4 weeks after the exposure became evident. The difference was statistically significant between the week 2 and week 6 visits (P = 0.008) for each previously exposed site. The histologic observation of barrier remnants revealed direct apposition of fibrous and bone tissues on the membrane surface.

CONCLUSION

In cases of membrane exposure, gingival dehiscences always disappeared in the following weeks without affecting the healing process. Histologic results showed barrier stability over a 6-month period, promoting bone regeneration.

Secretion of gelatinases and activation of gelatinase A (MMP-2) by human rheumatoid synovial fibroblasts

In monolayer cultures human rheumatoid synovial fibroblasts (HRSF) secrete gelatinase A (MMP-2) and, unlike other human fibroblasts, to a minor extent also gelatinase B (MMP-9) as inactive proenzymes. In this regard HRSF resemble the fibrosarcoma cell line HT-1080. Unlike HT-1080, however, HRSF do not increase the secretion of MMP-9 in response to phorbol-12-myristate-13-acetate. This indicates that in HRSF the protein kinase C pathway for an enhanced MMP-9 secretion is inactive. None of the substances used in our study increased MMP-9 secretion, but some of them inhibited MMP-9 secretion. The secretion of MMP-2 could not be enhanced either, not even by dbcAMP, which has been reported to be effective in Sertoli and peritubular cells. Activation of MMP-2 in HRSF could be induced by treatment with concanavalin A (ConA) or cytochalasin D, as was shown for other cell types. This activation was not accompanied by a significant change in the amount of secreted TIMP-1 and TIMP-2. In contrast to reports on human skin fibroblasts, however, the activation of MMP-2 could not be induced in HRSF by treatment of the cells with monensin or sodium orthovanadate. Moreover, monensin was shown to act as an inhibitor of ConA- or cytochalasin D-mediated activation. Additionally, and in contrast to a report on a rat fibroblast cell line, MMP-2 activation is not mediated via the MAP kinase pathway in HRSF: PD 98059, a specific inhibitor of MAP kinase kinase, did not inhibit the activation of MMP-2. Similarly ineffective were PD 169316, an inhibitor for p38 MAP kinase, other inhibitors for protein kinases as lavendustin A, Gö 6983, wortmannin, rapamycin, as well as the protein tyrosine kinase inhibitors herbimycin A and genistein. Only staurosporin, a broad spectrum inhibitor of protein kinases, and the ionophores monensin and A 23187 effectively inhibited MMP-2 activation in HRSF. Our results demonstrate that MMP-2 can be activated by quite different pathways, and that different cells, even when belonging to the fibroblast family, do not necessarily use the same activating pathways.

Local versus systemic adjunctive antibiotic therapy in 28 patients with generalized aggressive periodontitis

BACKGROUND

Although the use of systemic antibiotics has been studied in patients with generalized aggressive periodontitis (formerly rapidly progressive periodontitis), the use of adjunctive tetracycline fibers in these patients has not been reported. The purpose of the present study was to compare the clinical response of local versus systemic antibiotic treatment as adjuncts to scaling and root planing in patients with GAgP.

METHODS

After initial therapy and full-mouth scaling and root planing (SRP), 30 patients were randomly assigned to 1 of 2 antibiotic treatment groups. Probing depth (PD), clinical attachment level (CAL), and bleeding on probing (BOP) were recorded with an automated probe prior to SRP at baseline (BL) and 15, 30, 41, and 54 weeks later. Three months after SRP, the patients were treated with amoxicillin/clavulanic acid (500 mg tid; SRP + AUG group) or with local tetracycline fiber in pockets with PD > or =5 mm (SRP + TCF group).

RESULTS

In both treatment groups, PD decreased significantly from BL to week 54 (6.2+/-1.5 mm to 4.7+/-1.4 mm for SRP + TCF and 6.5+/-1.4 mm to 4.2+/-0.6 mm for SRP + AUG). However, there was no statistically significant difference between the 2 groups in pocket reduction. Similarly, in both treatment groups, there were small but significant gains in CAL from BL to week 54 (12.0+/-1.8 mm to 11.3+/-1.8 mm for SRP + TCF and 12.3+/-1.5 mm to 11.2+/-1.2 mm for SRP + AUG). The difference in CAL gain between the 2 groups was not statistically significant. At the final examination, both groups showed significant PD reduction and CAL gain (P <0.001) compared to BL. The frequency and percentage of bleeding sites decreased significantly in both groups. At week 54, this decrease was significantly greater in the SRP + AUG group (31.67% for SRP + TCF versus 3.85% for SRP + AUG).

CONCLUSIONS

These results indicate that the local delivery of tetracycline by a fiber or the systemic administration of amoxicillin/clavulanic acid given 3 months after scaling and root planing produced similar clinical outcomes over the 9-month observation period.

Total IgA and Porphyromonas gingivalis-reactive IgA in the saliva of patients with generalised early-onset periodontitis

Generalised early-onset periodontitis (GEOP) is characterized by acute inflammatory bursts, resulting in rapid destruction of the periodontal apparatus in young adults. An impaired host defense seems to play an important role as etiological factor of periodontitis, especially in the development of GEOP. As the gram-negative Porphyromonas gingivalis has been identified as one of the causative anaerobic bacteria, the humoral immune response to this micro-organism is of particular interest in patients with GEOP. To evaluate the local immune status, we measured total and P. gingivalis-reactive salivary IgA in GEOP patients and in age- and gender-matched periodontally normal controls. We found a significantly lower concentration and secretion rate of total salivary IgA in the GEOP group. Although no differences were detected in the concentration or secretion of P. gingivalis-reactive IgA between groups, the specific fraction of P. gingivalis-reactive IgA of the total IgA was significantly higher in the GEOP group. These findings indicate an inhibition of total secretory IgA in GEOP, while the P. gingivalis-reactive humoral immune system in saliva is, however, activated. P. gingivalis seems to selectively activate IgA lymphocyte clones and induces a switch in the fraction of specific IgA.

Suppression of interleukin-10 release from human periodontal ligament cells by interleukin-1beta in vitro

Periodontitis is characterized by an inflammatory process induced by periodontopathogenic bacteria in the subgingival plaque. Periodontal inflammation can be enhanced by both an increase of inflammatory stimulators, e.g. interleukin (IL)-6, and a decrease of inflammatory inhibitors, e.g. IL-10. The amount of IL-1beta is known to be increased in gingival tissues and in the gingival crevicular fluid from inflamed sites compared to healthy sites. This in vitro study sought to clarity whether IL-1beta (1 ng/ml) has a regulatory effect on the release of these two cytokines from human periodontal ligament (PDL) cells. PDL cells derived from healthy premolars were grown in the presence and absence (control) of IL-1beta. The concentration of IL-6 and IL-10 in the supernatants was assessed by enzyme-linked immunosorbent assay after 48 h of culture. PDL cells incubated with IL-1beta released significantly (p < 0.05) higher amounts of IL-6 and significantly (p < 0.01) smaller amounts of IL-10 compared to control. These results give further support to the observation that IL-1beta can increase the IL-6 secretion from PDL cells. Moreover, they provide original evidence that PDL cells secrete IL-10, which can be suppressed by IL-1beta. It is concluded that PDL cells can function as accessory immunoinflammatory cells amplifying the inflammatory process in periodontitis and, thereby, contributing to periodontal breakdown.

Repeated local metronidazole-therapy as adjunct to scaling and root planing in maintenance patients

The purpose of this investigation was to evaluate the effect of local antibiotic therapy with metronidazole adjunctively to scaling and root planing (SRP) versus mechanical treatment alone. 30 maintenance-patients were included in this single-blind study. The subjects had to comply with the following criteria: 2 non-adjacent sites with a probing depth > or =6 mm with bleeding on probing in separate quadrants, no periodontal therapy within the last 3 months, and no antibiotic therapy within the last 6 months. After randomization, the study sites were assigned to one of the following 2 treatments: SRP plus subgingival application of metronidazole 25% dental gel (Elyzol) 5x during 10 days (test site) or SRP alone (control site). Subgingival microbiological samples were taken prior to, and 21 days and 3 months after scaling. The samples were analyzed with a commercial chair-side ELISA (Evalusite) for Porphyromonas gingivalis, Prevotella intermedia and Actinobacillus actinomycetemcomitans. Probing pocket depth (PPD), attachment level (AL) and bleeding on probing (BOP) were recorded at baseline and 3 months later. PPD reduction and AL-gain were statistically significant (p<0.001) after both treatments. However, there were no statistically significant differences between them. The same observation was made for BOP. P. gingivalis was reduced significantly after both treatments without statistically significant differences. P. intermedia was reduced significantly only after SRP. A. actinomycetemcomitans was not reduced significantly after either treatment. In conclusion, the repeated local application of metronidazole as an adjunct to SRP and the mechanical treatment alone showed similar clinical and microbiological effects without statistically significant differences with the exception of P. intermedia.

Comparative antiplaque effectiveness of an essential oil and an amine fluoride/stannous fluoride mouthrinse

The adjunctive use of antimicrobial mouthrinses to help control supragingival plaque and gingivitis has been shown to contribute significantly to patients' daily oral hygiene regimens. This controlled clinical study used an observer-blind, randomized, cross-over design in a 4-day plaque regrowth model to determine the relative efficacies of an essential oil-containing mouthrinse (Listerine Antiseptic) and an amine fluoride/stannous fluoride-containing mouthrinse (Meridol) in inhibiting the development of supragingival plaque. A 0.1% chlorhexidine mouthrinse (Chlorhexamed-Fluid) was used as a positive control, and a 5% hydroalcohol solution was used as a negative control. Dosing for each of the test mouthrinses was based on the manufacturers' label directions. Because the volume and rinse time for each of the test mouthrinses were different, each test mouthrinse had its own negative control group. On day 1 of each test period, subjects received an oral soft and hard tissue examination and a dental prophylaxis to remove all plaque, calculus, and extrinsic stain. Starting the same day, subjects refrained from all mechanical oral hygiene procedures for the next 4 days and rinsed 2x daily under supervision with their randomly-assigned mouthrinse. On day 5, each subject received a plaque assessment as well as an oral examination to assess side effects. Each test period was separated by a 2-week washout period. 23 volunteers with a median age of 26 years completed the study. Compared to the respective placebos, the median percent plaque reductions at 5 days were 23.0%, 12.2%, and 38.2% for the essential oil, amine/stannous fluoride, and chlorhexidine rinses, respectively. The plaque reductions seen in the essential oil and chlorhexidine rinse groups were statistically significant (p < 0.001), while the plaque reduction in the amine/stannous fluoride rinse group was not statistically significant (p > 0.05). Additionally, the essential oil rinse was significantly more effective (p < 0.001) than the amine/stannous fluoride rinse in inhibiting plaque accumulation in this clinical model.

Local metronidazole application in maintenance patients. Clinical and microbiological evaluation

The purpose of this investigation was to evaluate the clinical and microbiological effect of local antibiotic therapy in comparison with subgingival scaling and root planing in a randomized semi-masked study. Forty-six recall patients who completed systematic periodontal therapy 6 to 24 months prior to the study were enrolled. The inclusion requirements were at least one site with probing depth > or = 5 mm in each quadrant, no scaling, and no antibiotic therapy during the last 6 months. After randomization each patient received 2 different treatments: in 2 quadrants metronidazole 25% dental gel was applied subgingivally to the pockets at day 0 and day 7; scaling and root planing was carried out in the 2 other quadrants, one at day 0 and in the remaining quadrant at day 7. Subgingival microbiological samples were taken from each patient before treatment and on days 21, 91, and 175 after the treatment. The analyses were carried out by indirect immunofluorescence assay. At all treated sites probing depth (PD), clinical attachment level (CAL), and bleeding on probing (BOP) were recorded on days 0, 21, 91, and 175. Both treatments resulted in PD reduction and CAL gain. PD reduction was statistically significant (P < 0.01) for both treatment modalities after 6 months. The CAL gain was not significant for either treatment. There was no statistical significance between scaling and antibiotic therapy. Treponema denticola, Porphyromonas gingivalis, and Prevotella intermedia were significantly reduced after therapy; however, there were no statistically significant differences between treatments. If Actinobacillus actinomycetemcomitans was present before therapy, it was also present after treatment in both groups. The conclusion is that, in recall patients, local application of metronidazole and scaling and root planing showed similar clinical and microbiological effects without statistically significant differences.

A clinical study comparing two high-fluoride dentifrices for the treatment of dentinal hypersensitivity

Amine fluoride, the active ingredient of a currently marketed dentifrice in Germany and other European countries, and sodium fluoride were compared to a placebo dentifrice for their effectiveness in alleviating dentinal hypersensitivity. This was a randomized, double-blind, two-center, parallel clinical study covering 8 weeks of product use by 115 subjects. The hypersensitivity of the affected teeth was assessed by tactile stimulation, cold air stimulation, and overall subjective patient response. The three treatment groups exhibited comparable baseline sensitivity. These three methods of clinical assessment demonstrated that the desensitizing ability of a relatively higher fluoride dentifrice (1,400 ppm), delivered either as amine fluoride or sodium fluoride, did not differ significantly from that of the placebo dentifrice.

The occurrence of treponemes and their spherical bodies on polytetrafluoroethylene membranes

The occurrence of small (diameter 0.125 micrometers) and large (diameter 0.27 micrometers) treponemal species on expanded polytetrafluoroethylene membranes were demonstrated in vivo. In the apical part of the expanded polytetrafluoroethylene membrane only the smaller treponemes were colonizing, while in other parts a mixed population of different bacterial species including large treponemes was seen. Only the smaller treponemes were able to form spherical bodies in the occlusive part of the membrane. All morphological characteristics of spherical bodies such as common outer sheath, randomly distributed axial flagella, sheathless protoplasmic cylinders and central bodies could be differentiated. Possible causes for the formation of spherical bodies are discussed.

Induction of metalloproteinase activity, cartilage matrix degradation and inhibition of endochondral mineralization in vitro by E. coli lipopolysaccharide is mediated by interleukin 1 alpha

Chronic inflammation and degradation of connective tissue in the course of periodontitis are maintained by bacterial products such as lipopolysaccharides (LPS), which probably act via inflammation mediators, e.g. cytokines. We investigated the effects of lipopolysaccharide (LPS) from E. coli and mouse recombinant interleukin 1 alpha (mrIL-1) on chondrogenesis, endochondral mineralization, matrix metalloproteinase activation and matrix degradation in vitro using cartilage organoid cultures. Mesenchymal cells of limb buds from mouse embryos (day 12) were grown at high density on a membrane filter at the medium/air interphase for 14 days. Chondrogenesis occurred during the first 6 days of culture. Endochondral mineralization took place upon addition of 5 mM beta-glycerophosphate from day 7 to 14. Treatment of the cultures with LPS and mrIL-1 on days 2 to 14 and during mineralization on days 7 to 14 resulted in a marked decrease of types I and II collagen, matrix mineralization and proteoglycan content. In the medium, proteoglycan content and metalloproteinase activity were enhanced. LPS induced IL-1 alpha production and release into the medium. LPS antagonist polymyxin B partly abolished the LPS effect, whereas IL-1 receptor antagonist (IL-1ra) partly abolished both LPS and mrIL-1 effects. Reversal of LPS-induced effects by IL-1ra was comparable to the reversal of mrIL-1 effects, only the decrease in type II collagen after LPS treatment was abolished to a lesser extent by IL-1ra.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibition of chondrogenesis and endochondral mineralization in vitro by different calcium channel blockers

Limb bud mesenchymal cells from mouse embryos grown at high density at the medium/air interphase undergo chondrogenesis and form numerous nodules of mature cartilage. Addition of beta-glycerophosphate (5 mM) induced endochondral mineralization within these nodules. Ca2+ accumulation, matrix formation and alkaline phosphatase activity were recorded for each culture. Treatment with the L-type channel-specific blockers nifedipine and verapamil during the entire culture period caused an inhibition of mineralization. Sequential treatment reduced mineralization only when added during the early part of the culture period in the course of chondrogenesis. In all cases, matrix formation, estimated by alcian blue binding, was concomitantly diminished. Lanthanum acetate, which blocks Ca2+ channels non-specifically, also reduced Ca2+ accumulation in the cultures when added continuously. After sequential treatment, Ca2+ content was only diminished when the cultures were treated in the last part of the culture period during mineralization. Matrix formation was not altered by lanthanum acetate, but alkaline phosphatase was decreased. These results show that chondrogenic differentiation is under control of L-type Ca2+ channels, whereas matrix calcification depends on intracellular Ca2+ accumulation mediated by lanthanum-sensitive Ca2+ channels. This points to the importance of intracellular Ca2+ accumulation in the process of endochondral mineralization.

Application of the community periodontal index of treatment needs (CPITN) in a group of 45-54-year-old German factory workers

The purpose of the present study was to assess the periodontal status of 45-54-year-old patients and to evaluate their treatment needs. Probing depths, bleeding on probing and retentional elements (calculus and overhanging restorations) were determined according to the community periodontal index of treatment needs (CPITN). Additionally, loss of attachment was measured. Results indicated that none of the subjects had a completely healthy periodontium; only 14.7% presented with single sextants which were healthy or needed only improved oral hygiene. Slightly less than half (46.1%) of the subjects were classified as treatment need (TN) category 2 and the remainder (53.9%) as TN3. Of the subjects classed as TN category 3, 14% had the requisite code 4 in one sextant, 18.2% in 2 sextants, 21.7% in half or more of the sextants and 4.2% in all sextants. With a mean of 5.55 sextants per patient, 0.2 sextants per person were scored as code 0 or 1, 1.33 sextants as code 2, 2.79 sextants as code 3 and 1.24 sextants as code 4. The mean loss of attachment was 3.8 mm. Anterior teeth showed less loss of attachment than posterior teeth and buccal and lingual surfaces showed less loss of attachment than mesial and distal surfaces. The data indicate that although this group of 45-54-year-old subjects had high CPITN scores in total TN categories, the codes for complex Treatment Needs (TN3) were recorded only in localized areas.

The double lateral bridging flap for coverage of denuded root surface: longitudinal study and clinical evaluation after 5 to 8 years

Longitudinal results of a 5 to 8 year follow-up study of the double lateral bridging flap for coverage of gingival recessions (GR) are presented. On a total of 75 GR in 18 patients (31 surgical procedures) the majority of the teeth (58%) showed a root denudation reduction of 75% or more. Total coverage was observed on 18 teeth (24%). Examinations did not show a high correlation between the extent of recession and bone dehiscence after surgery, between the degree of root coverage and the initial width of keratinized gingiva, or between the GR before and after surgery. We conclude that neither the quantity of gingival recession nor the quality of the supporting tissues were a prerequisite for the success of this surgical technique.

Immunohistochemical distribution of extracellular matrix proteins as a diagnostic parameter in healthy and diseased gingiva

This study showed histopathological findings of the extracellular matrix in healthy, inflamed, and hyperplastic human gingiva with immunohistochemical techniques. The distribution of collagen types V and VI, as well as of glycoprotein fibronectin, shows that they are extracellular matrix structural components which differentiate the tissue pathology. The orientation of the collagen fibers, the intensity of the fluorescent staining, the thickness of the fibrillar component, and the topographical localization of the connective tissue proteins are important parameters for tissue morphology. Therefore, bacterial deposits and the pharmacodynamic properties of drugs associated with gingival hyperplasia lead to an alteration of the matrix compared to the healthy tissues. This may be important in the tissue pathology in cases when the medical history of the patient is not known, as well as in forensic medicine.

Extracellular matrix analysis of nifedipine-induced gingival overgrowth: immunohistochemical distribution of different collagen types as well as the glycoprotein fibronectin

The purpose of this study was to demonstrate the localization of collagen types I, III, IV, V, VI and VII as well as the glycoprotein fibronectin in nifedipine-induced gingival overgrowth. The slices, after the use of indirect immunofluorescence (incubation with antibodies against these extracellular matrix components), showed a diffuse distribution with the anti-types I and III in the stroma and fluorescent staining of the basement membranes of the epithelium, blood vessels and nerves with collagen type IV antibodies. The increased number of vessels was localized near the surface of the lesion. Collagen type V - seen as a filamentous - and collagen type VI - as microfibrillar - components were also localized in the tissue, showing completely different patterns of distribution. Collagen type V appeared "crater"-like and type VI displayed a "honeycomb"-shaped structural model. The blood vessels were not stained but the area around their walls demonstrated an intense fluorescence with these antibodies. Collagen type VII showed a characteristic linear staining near to the epithelial basement membrane. In contrast to this, fibronectin localized with a varied intensity in the different areas of the tissues and presented a "cloud"-like structure. This shows differences between the matrix components in nifedipine-induced hyperplasia and confirms the heterogeneity of the matrix in health and in gingival alterations.

Distribution of fibronectin in healthy, inflamed and drug-induced gingival hyperplasia

The distribution of fibronectin (FN) in the healthy, inflamed and hyperplastic human gingiva was investigated by indirect immunofluorescence. FN appeared as a fibrillar structure in the lamina propria of the healthy gingivae. In the inflamed specimens, FN demonstrated parallel fibres, especially in the coronal areas of the tissue. In the phenytoin gingival overgrowth, tissue FN was observed as thin fibres with variable length. The thin fibres gave the appearance of penetrating the basement membrane of the epithelium. Cyclosporin A gingival enlargement could be differentiated by phenytoin lesions because of the higher length and the parallel distribution of the FN. Finally, FN was observed in the nifedipine gingival overgrowth, where a microfibrillar delicate network gave the appearance of a "cloud"-pattern of distribution. In all of the specimens, blood vessels and nerves could not be stained. These findings show that FN distribution could differentiate the structure of the gingival lesions.

Inhibition of plaque accumulation under periodontal dressing by sustained-release varnish of chlorhexidine

Slow-release varnish containing chlorhexidine was applied prior to the application of a periodontal dressing. The ability of the slow-release varnish to inhibit accumulation of dental plaque under the dressing was compared to a placebo varnish. Seven volunteers were fitted with periodontal dressing on the lower and upper jaws. One jaw was pre-coated with slow-release varnish containing chlorhexidine, while the other was coated with a placebo. A week later the dressings were removed and the plaque under the dressing was scored. Significantly less plaque was found on teeth pre-coated with the slow-release varnish containing chlorhexidine as compared to the control. An increase in the amount of gingival fluid was observed in both the control and experimental groups after removing the periodontal dressing.

Immunohistochemical localization of collagenous components in healthy periodontal tissues of the rat and marmoset (Callithrix jacchus). I. Distribution of collagen types I and III

The distribution of collagen types I and III was demonstrated in healthy periodontal tissues of the rat and marmoset using immunofluorescent localization after decalcification of the maxillae and mandiblae in 0.2 N HCl. An intense fluorescence in the alveolar bone and cementum matrix, as well as in the soft periodontal tissue, was demonstrated with anti-collagen type I antibodies. In the gingival connective tissue and in the periodontal ligament thick fibers of collagen type I could be observed. The fluorescent reaction in the rat periodontal ligament was not strong in comparison to the marmoset periodontal ligament. Sharpey's fibers, inserting into the cementum and alveolar bone, were also stained. On the other hand, collagen type III could not be demonstrated in the hard periodontal tissues, but could be in the bone marrow stroma and the incremental lines as well as around the Sharpey's fibers of the cementum, in accordance to previous studies. In the gingival connective tissue a strong staining was evident, especially near the basement membrane. The periodontal ligament showed an intense fluorescence that was, in some areas, continuous with Sharpey's fibers inserting into the cementum. The distribution of collagen types I and III was demonstrated with immunohistochemical techniques in the rat and marmoset periodontium. These results provide necessary information on healthy tissues that will be required for future studies on the effects of pathological, reparative and regenerative processes.

Immunohistochemical localization of collagenous components in healthy periodontal tissues of the rat and marmoset (Callithrix jacchus). II. Distribution of collagen types IV, V and VI

The immunohistochemical distribution of collagen types IV, V and VI has been demonstrated in healthy periodontal tissues of rats and marmosets following decalcification of the maxillae and mandibulae in 0.2 N HCl. An intense fluorescence with anti-collagen type IV antibodies was demonstrated in the basement membranes of the epithelium and of the blood vessels and nerves. In the alveolar bone stroma and in the periodontal ligament (PL) collagen type IV was present only in the basal membranes of the blood vessels and nerves. In comparison, collagen type V was observed in a fibrillar pattern in the gingival connective tissue, as well as the PL. In the PL, type V collagenous fibers demonstrated a parallel distribution with stronger fluorescence near the cementum surface. Collagen type VI could be demonstrated in fine fibers present in the gingival connective tissue and the PL. Blood vessels and nerves were not stained in the marmoset, but were in the rat, where a localization of collagen type VI was demonstrated in these areas. Alveolar bone and cementum, as well as the Sharpey's fibers embedded in these tissues, were not stained with antibodies against collagen type V and type VI, but a pericellular localization of these collagenous components could be observed. Collectively, these results provide basic information on the relative distribution of different collagen types in normal tissues of rats and marmosets that will be required for future studies on the effects of pathological, reparative and regenerative processes.

[Treatment of a patient with advanced periodontitis]

This case report presents the planning and clinical treatment of a patient with advanced periodontitis and insufficient prosthetic reconstruction. After initial therapy with extraction of the unrestorable teeth, periodontal surgery was performed partly by means of the implantation of hydroxyapatite into bony defects. The prosthodontic treatment consisted of a fixed/removable prosthesis in the maxilla, together with a shortened teeth arch in the mandible. This clinical treatment, combined with regular recalls, has ensured the patient a functional and esthetic reconstruction for a period of 4 years.

Immunohistochemical distribution of the collagen types IV, V, VI and glycoprotein laminin in the healthy rat, marmoset (Callithrix jacchus) and human gingivae

The purpose of this study was to demonstrate the localization of collagen types IV, V and VI as well as the glycoprotein laminin in biopsies of healthy rat, marmoset (Callithrix jacchus) and human gingivae. The slices, after the use of indirect immunofluorescence (incubation with antibodies against these extracellular matrix components), showed the same distribution with the anti-type IV and laminin antibodies on the basement membranes of the epithelium, blood vessels and nerves. Collagen type V, as a filamentous, and collagen type VI, as microfibrillar components, were localized in a similar pattern in the different species. In contrast to the other species, collagen type VI could not be found near the basement membranes of vessels and nerves of the marmoset gingiva. This result shows differences between human and monkey tissues, but not between rat and human gingivae, and conforms the heterogeneity of collagen type VI in the various cell and tissue types.

[Collagen as a basic element of the periodontium: immunohistochemical aspects in the human and animals. 2. Cementum and periodontal ligament]

Immunohistochemical knowledge of the distribution of the collagen types in the cementum and periodontal ligament were reported in this paper. Because of the different localization of each of these collagenous components in the two periodontal tissues its function in the matrix was explored. It was also possible to clarify the role of collagen in healthy periodontium as well as in regeneration and wound healing mechanisms.

[Collagen as a basic element of the periodontium: immunohistochemical aspects in the human and animal. 1. Gingiva and alveolar bone]

The connective tissue (CT) is responsible for stability and function of the whole periodontium. It consists of cells, which are embedded in the extracellular matrix. Collagen plays the main role for the function of the periodontal unit. Collagen types I, III, IV, V and VI are distributed in a different pattern in all periodontal tissues, as has been here demonstrated in the gingiva and alveolar bone. Collagen type I, as a characteristic collagen type of the hard tissues, has been demonstrated by thick collagen fibers in the alveolar bone and in the gingival connective tissue. It can be differentiated from the thinner collagen type III fibers, which are localized in the gingiva (especially under the basement membrane of the epithelium) as well as only in the bone marrow stroma. The epithelium, blood vessels and nerves contain the characteristic collagen type IV in their basement membrane Filamentous (collagen type V) and microfibrillar (collagen type VI) components demonstrate different patterns of distribution, especially around the bone cells and in contrast to the other collagen types of fibrillar networks in the gingival CT. This morphological differentiation of the extracellular matrix components of the periodontium allows conclusions in the pathological and inflammatory processes as well as in the regenerative and reparative procedures.

[Healing and integration of ePTFE membranes]

In this study 40 patients with adult periodontitis received periodontal therapy with ePTFE membranes according to the principle of guided tissue regeneration. Membranes were subgingivally implanted for a period of 4 to 6 weeks. The tissue response was examined clinically and, in 7 cases, also histologically. After removal of the membranes, the membranes themselves and biopsies of the underlying regenerated tissue were prepared for light- and transmission electron microscopy. Clinically most cases showed membrane exposure with recessions and gingival pockets between membrane and gingiva. Histologically all exposed parts of the membranes were contaminated by microorganisms. In the superficial layers of the biopsies microorganisms were found between neutrophils, degenerated collagen fibrils and necrotic cell components.

[Guided bone tissue regeneration--a clinical and histological pilot study]

The aim of the present investigation was to study whether a technique based on the principle of guided tissue regeneration is able to generate new osseous tissue around osseointegrated implants in humans. 14 titanium implants (IMZ) were inserted in 4 patients. The fixtures were modified by hydroxyapatite (HA) or titanium discs measuring 3 mm in height, which were screwed onto the implants. The modified implants were inserted in such way, that the discs were above the level of the alveolar bone. 3 modalities of treatment were performed. In group I HA granules were placed on the bone around the disc-implant-constructions and completely covered by an ePTFE membrane in order to create a space for ingrowth of bone-derived cells. In group II the membrane alone was placed and in the control group HA granules alone were used. After complete closure of the flap and 2-4 months of healing, the membranes including the generated tissue and the discs were removed and processed for histological examination. Clinical results demonstrated that in group I hard tissue had formed underneath the membrane, which strongly adhered to alveolar bone. Histological examination revealed new formation of trabecular bone. When the membrane alone was used, the created space was almost completely reduced during healing and no significant tissue formation had occurred. The greatest clinical problem was flap dehiscence over the membrane. In the control group the HA granules and discs were encapsulated in connective tissue. Limited by the small number of sites, the study indicates that a membrane technique according to the principle of guided tissue regeneration promotes new bone formation around osseointegrated implants in humans.

[Role of antibodies in periodontal disease]

Bacteria and their products play a key role in the etiology of periodontitis. They activate the host immunologic system which produces specific immunoglobulins (Ig). Mainly IgA, IgG and IgM are found in the oral environment, in the saliva IgA are present as secretory IgA. In case of periodontitis, the tissular destruction could be practically explained by spontaneous hypersensibility reactions which may contribute to deteriorate the periodontal tissues. Considering the complexity of the factors involved in periodontal inflammation (i.e. bacterial variety, difference of properties, patient's individuality, difference of analysis methods), the question of the exact role played by the antibodies still remains open.

[Implantation of porous hydroxyapatite into periodontal bony defects]

The purpose of the present report was to evaluate on a clinical and histological level the effect of hydroxylapatite (HA)--Interpore 200--implanted into various types of periodontal defects. Additionally in-vitro studies with enzymatically released calvarial cells from fetal rats were performed in the organoid culture system. The clinical data 12 months after surgery revealed a greater reduction of probing depths (PD) and gain of attachment level in the implanted sites (59 sites) when compared to the sites treated by open flap curettage (40 sites). When the results were analyzed according to the initial PD the measurements showed no significant difference between the two modalities of treatment in moderately deep pockets (PD less than or equal to 6 mm) in contrast to deep and extremely deep pockets (PD = 7-9 mm and PD greater than 9 mm). In order to collect data about the type of periodontal wound healing biopsies, respectively block sections were taken 6-12 months after therapy in 6 patients and evaluated by light microscopy. Three forms of tissue reaction in relation to the implants were observed. The first consisted of a fibrous connective tissue encapsulation of the implants, the second showed organized bone tissue around the HA, while the third type of tissue reaction consisted of a deposit of mineralized tissue on the surface limited in width, which was interpreted as cementum formation. Analysis of the block sections revealed new connective tissue attachment to a certain extent and bone/cementum-like tissue formation. The possibility of cementum-like tissue formation on HA was confirmed transmission electronmicroscopically by the in-vitro experiments.(ABSTRACT TRUNCATED AT 250 WORDS)

[Awareness of oral health in 45 to 54-year old Berlin subjects and correlation with clinical periodontal findings]

143 subjects 45-54 years old were interviewed by questionnaire about their oral hygiene behaviour, their knowledge about periodontal diseases and their opinion concerning prophylaxis and therapy of periodontitis. The CPITN and the loss of attachment was measured at each tooth by clinical examination. Then the clinical data were examined for possible correlation to socioeconomic factors, gender or behaviour and knowledge of the subjects. Women showed statistically significant better clinical data than men, but no correlation to CPITN classes was found in analyzing education, profession or income. Also clinical data could not be found influenced by the frequency of toothbrushing and frequency of seeing a dentist or by the patients knowledge. However, increasing knowledge about their disease significantly increased the subjects willingness to undergo a long-term treatment. The subjects examined were interested in oral health, but their clinical data indicated that motivation or knowledge was not converted sufficiently into practice.

Bone formation by rat calvarial cells grown at high density in organoid culture

Calvarial cells from day 21 rat fetuses were isolated by enzymatic digestion and grown at high density in an organoid culture system at the medium/air interface. In this type of culture, mineralization occurred as early as 7 days in vitro, as revealed by light and electron microscopic means. After about 18 days in vitro, most of the culture consisted of mineralized tissue. Mineralization was also achieved without beta-glycerophosphate, but it was delayed by 2 to 3 days. Maximal alkaline phosphatase activity occurred at days 8 to 12 in vitro and then declined continuously during further cultivation. Two types of mineralization could be observed: (1) mineralization of a collagen-rich osteoid by typical apatite crystals; (2) mineralization of a nearly collagen-free matrix by amorphous material which was possibly secreted by the cells. The importance of higher cell densities for cell differentiation and formation of histotypic tissue in vitro is apparent, and it is indicated that cell-cell contacts and cell-matrix interactions may be prerequisites for the development of histotypic conditions similar to the in vivo situation.

Influence of free gingival grafts on the health of the marginal gingiva

In order to evaluate the effect of increasing the width of inadequate attached gingiva on the health of the marginal gingiva, 12 free gingival grafts were performed on 12 patients with less than 1.0 mm of attached gingiva on homologous contralateral pairs of mandibular teeth. A baseline examination, which included measurements of plaque, gingival exudate, sulcus bleeding, sulcus probing depth and width of attached gingiva, was done before surgery. One week after surgery, plaque was eliminated mechanically on the test and control sides. All measurements were repeated 7 and 14 weeks after surgery. During the week following the first postsurgical examination, individual oral hygiene instruction was given until the patient could show plaque-free test and control sites. The width of the attached gingiva increased significantly on the side where the grafting was performed (test side). The only other significant changes observed during the experiment were a decrease of the mid-buccal plaque index on the test side during the first 7 weeks following surgery and a decrease of the buccoproximal plaque index on the test and control sides during the total experimental period (14 weeks). None of the other clinical parameters measured showed significant differences when test and control sites were compared or when the same sites were compared longitudinally.

[Free grafts of attached and papillary gingiva]

In order to evaluate both attached and papillary gingiva as donor site for free gingival graft, 22 patients were operated and controlled 1, 3, 6 and 24 months postoperatively. The initial topography of donor sites encountered only transitory modifications. A better transplant color (when compared with transplant from the palate), the absence of palatal wound, the fixation of the graft with cyanoacrylate, the absence of sutures and periodontal pack not only reduced the operative time by more as the half but also contributed to a less painfull and more aggreable postoperative result.

Changes in the differentiation pattern of oral mucosal epithelium following heterotopic connective tissue transplantation in man

Anterior palatal connective tissue was transplanted into wound beds created within the alveolar mucosa of the lower anterior vestibulum in seven adults females. Six months postoperatively, the epithelial lining of the inverted transplants was biopsied and compared histologically, histometrically, and stereologically to the neighboring mucosal epithelium. The data suggest that (1) connective tissue of the lamina propria is primarily responsible for the structural specificity of the overlying epithelium, (2) inductive stimuli are not confined to superficial layers but also originate from deep portions of the lamina propria, (3) these stimuli influence both the epithelial differentiation and the type of epithelium-connective tissue interface, and (4) the epithelial response to the inductive stimuli in man may depend on the individual type of epithelial differentiation pattern originally prevailing at the recipient site. The transplant-lining epithelium assumed features resembling that of the hard palate in subjects with an alveolar mucosal epithelium with cheek-type characteristics. In subjects with an alveolar epithelium displaying a mixed differentiation pattern, the transplant-lining epithelium continued to generate a mixed pattern or else shifted to more palate-like characteristics.