Effects of tobacco smoke on the secretion of interleukin-1beta, tumor necrosis factor-alpha, and transforming growth factor-beta from peripheral blood mononuclear cells.

Alterations of the host response caused by short-term exposure to high levels of smoke during the act of smoking (acute smoke exposure) as well as long-term exposure to lower levels of tobacco substances in the bloodstream of smokers (chronic smoke exposure) may play a role in the pathogenesis of periodontal diseases in smokers. In this study, we examined the secretion of three cytokines [interleukin (IL)-1beta, tumor necrosis factor (TNF)-alpha, and transforming growth factor (TGF)-beta] from mononuclear blood cells from current smokers and non-smokers exposed to in vitro tobacco smoke (which may be comparable to in vivo acute smoke exposure) and mononuclear blood cells from current smokers not exposed to further in vitro smoke (which may be comparable to chronic smoke exposure). Peripheral blood mononuclear cells were isolated from eight healthy current smokers and eight healthy non-smokers, plated in culture wells, exposed in vitro for 1-5 min to cigarette smoke in a smoke box system or not exposed (baseline controls), and then incubated without further smoke exposure for another 24 h. Supernatants from each well were then collected and assayed for the concentrations of the three cytokines by enzyme-linked immunosorbent assay (ELISA). At baseline, mean IL-1beta levels were higher in smokers than in non-smokers (mean: 10.6 vs. 5.9 pg/ml, anova: P < 0.05). In both smokers and non-smokers, secreted levels of IL-1beta increased from 0 to 5 min of in vitro smoke exposure (mean: 5.9-9.9 pg/ml, t-test: P < 0.05 for non-smokers only) with levels in smokers higher than in non-smokers (P > 0.05). Mean TNF-alpha levels increased from 0 to 2 min of smoke exposure and decreased from 2 to 5 min in smokers and non-smokers, with higher levels in non-smokers than smokers at all time-points (P > 0.05). Mean TGF-beta levels were higher in smokers than in non-smokers at all time-points (mean: 180.5 vs. 132.0 pg/ml, P < 0.05 at 5 min only) with no significant alteration of the pattern of secretion with cigarette smoke exposure. These observed alterations in the secretion of cytokines from mononuclear blood cells in smokers, relative to non-smokers, and with in vitro smoke exposure may play a role in the pathogenesis of periodontal diseases in smokers.

[Periodontal disease--an additional risk factor for cardiovascular diseases?].

In 1989, a case-control study was published, linking between coronary heart disease and periodontal disease in the studied population. Since then, a number of additional studies, focused the attention to the possible role of dental infections in the pathogenesis of atherosclerosis. Some of these newer cohort studies, are prospective in nature, measuring incidence of the two diseases in large patient populations. The present article reviews these studies, and the proposed mechanisms which might explain the relationships between these two systemically distinct diseases.

Re-use of implant coverscrews changes their surface properties but not clinical outcome.

This study examined the effect of re-using coverscrews for dental implants (Brånemark) and the influence of re-use on clinical outcome. Nine patients, each receiving 3 implants in either the maxilla or the mandible, received 1 new coverscrew, 1 re-used coverscrew, and a third coverscrew that had been used multiple times. In all cases, the re-used coverscrews had been washed, mechanically cleaned, and steam-sterilized prior to re-implantation. Clinical outcome was assessed by X-ray analysis of the mandible/maxilla and light microscopy of histologically prepared sections of the overlying tissue. The surfaces of the coverscrews were characterized by profilometry, scanning electron microscopy (SEM), Auger electron spectroscopy (AES), and atomic force microscopy (AFM). There was no difference in clinical outcome whether the coverscrews were new or re-used multiple times. Histological evaluation showed no influence of re-use on the overlying epithelial and connective tissues at the time the coverscrew was removed. Surface topography and roughness changed with increasing number of uses, but surface chemistry was virtually unchanged. SEM and AFM analyses revealed the presence of machining marks, as well as deep scratches, across the surface of the re-used coverscrews. This study shows that coverscrews can be cleaned and re-used without any apparent adverse affect on clinical outcome. However, the cleaning procedures, as well as the surgical procedure, change the surface characteristics. If this approach were applied to the implant itself, it might affect osseointegration.

Using the PerioChip in treating adult periodontitis: an interim report.

Multicenter clinical trials have established that the adjunctive use of the subgingival controlled release of chlorhexidine, in the form of the PerioChip, significantly reduces pocket probing depth, improves probing attachment levels, and reduces bleeding on probing compared to scaling and root planing alone, for periods up to 9 months. The purpose of the present study was to report on the adjunctive use of the PerioChip for the long-term management of adult periodontitis for 2 years. A total of 836 patients with adult periodontitis from private dental offices were recruited into the trial. This interim report is on the first 72 patients to have completed the 2-year study. Treatments included initial definitive therapy followed by PerioChip placement in pocket sites with a pocket probing depth of > or = 5 mm after 1 month. Subsequently, the patients received routine periodontal maintenance therapy together with the placement of a PerioChip in pockets with pocket probing depths > or = 5 mm every 3 months. Results indicated that there was a continuous decrease in pocket probing depth over the 2 years (1.26 +/- 0.77 mm). This decrease in pocket probing depth was marked over the first 9 to 12 months, and then appeared to be less marked over the next 12 months. At 2 years, 60% of the patients had at least 2 pockets showing a reduction of 2 mm or more, and only 10% of the patients showed no change or increased pocket probing depth. The results indicate that adjunctive PerioChip use is a clinically effective treatment option for dental professionals and their patients for the long-term management of adult periodontitis.

Differentiation of monocytes to macrophages primes cells for lipopolysaccharide stimulation via accumulation of cytoplasmic nuclear factor kappaB.

During infection, circulating blood monocytes migrate from the vasculature to the extravascular compartments where they mature into tissue macrophages. The maturation process prepares the cell to actively participate in the inflammatory and the immune responses, and many transcription factors have been found to be involved. Here we report on a novel role for nuclear factor kappaB (NF-kappaB) in this process. Its accumulation in the cytoplasm of differentiated macrophages is responsible for the enhanced ability of the cell to respond to lipopolysaccharide (LPS) stimulation, as determined by tumor necrosis factor alpha (TNF-alpha) secretion. Differentiation of the human monocytic cell line THP-1 into macrophage-like cells was induced by exposure of the cells to phorbol myristate acetate. DNA-bindable NF-kappaB was not detected in the cytoplasm of undifferentiated THP-1 cells but accumulated in the cytoplasm of the cells following differentiation. No TNF-alpha was detected in the media of resting differentiated and nondifferentiated THP-1 cells. Stimulation with LPS of differentiated cells induced the production of higher levels of TNF-alpha than stimulation of nondifferentiated cells. This hyperresponsiveness to LPS was found in the mRNA and secreted TNF-alpha levels. Furthermore, stimulation with LPS induced the translocation of NF-kappaB from the cytoplasm into the nucleus. This translocation process was more rapid in the differentiated cells than in the nondifferentiated cells, and the resultant accumulated levels of NF-kappaB in the nucleus were higher. The DNA-bindable NF-kappaB was identified as a heterodimer of p65 and p50. The results suggest that NF-kappaB accumulation in the cytoplasm during maturation of monocytes to macrophages primes the cells for enhanced responsiveness to LPS and results in the rapid secretion of inflammatory mediators, such as TNF-alpha, by mature macrophages following LPS challenge.

In vivo exposure to Porphyromonas gingivalis up-regulates nitric oxide but suppresses tumour necrosis factor-alpha production by cultured macrophages.

The present study was designed to test whether the functional response of mouse macrophages elicited by chronic exposure to bacteria will be different from that of cells elicited by a non-bacterial irritant. Macrophage elicitation was conducted by Porphyromonas gingivalis, a major periodontal pathogen, in comparison to a standard elicitation by thioglycollate (TG). We measured lipopolysaccharide (LPS)-induced nitric oxide (NO) and tumour necrosis factor-alpha (TNF-alpha) secretion by the elicited macrophages, and the expression of inflammatory cytokines in the whole elicited cell population. In addition, we tested the response of TG-elicited macrophages to pretreatment with P. gingivalis LPS in vitro. Mouse peritoneal macrophages were harvested 4 days after intraperitoneal injection of TG or heat-killed P. gingivalis. TG-elicited macrophages produced undetectable levels of TNF-alpha and approximately 0.5 microM of NO. The stimulation of the macrophages with LPS resulted in the secretion of NO and TNF-alpha in a dose-dependent manner. The P. gingivalis-elicited macrophages produced basal levels of approximately 5 microM NO, but TNF-alpha was not detectable. LPS stimulation of these cells further increased the secretion of NO eightfold while TNF-alpha remained undetectable. The NO secretion by P. gingivalis-elicited cells was significantly higher than that by TG-elicited cells. Examination of cytokine expression in the whole elicited cell population revealed that both P. gingivalis-elicited cells and TG-elicited cells expressed messenger RNA for interleukin-2 (IL-2), TNF-alpha and interferon-gamma (IFN-gamma), but not for IL-4. IL-6 was expressed in P. gingivalis-elicited cells only. Pretreatment of TG-elicited macrophages with P. gingivalis LPS for 24 hr prior to a second LPS challenge resulted in down-regulation of TNF-alpha secretion and up-regulation of NO secretion, a response similar to that seen in P. gingivalis-elicited peritoneal macrophages. The results suggest that the in vivo exposure of resident macrophages to P. gingivalis induces functional changes in peritoneal macrophages. These changes might be due to the effect of P. gingivalis LPS.

Alveolar bone loss and restorative dentistry in the primary molars.

This study examined the relationship between the status of the interproximal alveolar bone and the nature of the adjacent proximal surfaces in the primary molar area. In bite wing radiographs of 354 children, aged 6 to 9 years, 5091 sites were examined; 72.7% of the sites were adjacent to intact proximal surfaces, 14.2% to untreated proximal carious surfaces, and 13.0% to restored proximal surfaces. Marginal alveolar bone loss (ABL) was evident in 26.8% of the children, at 4.0% of the sites. Two thirds of the children with ABL had bone defects in more than 1 site. Males had a significantly higher mean number of sites affected with marginal ABL, per child, than females (mean = 2.4, SE = 0.2 and mean = 1.8, SE = 0.2 respectively). ABL was found adjacent to: 0.8% of the intact surfaces; 16.9% of the carious surfaces; 7.8% of the restored surfaces; 1.8% and 53.8% of the sites without or with proximal contact loss respectively; 3.8% and 30.8% of the sites with or without an adequate amalgam restoration respectively; 4.9% and 25.8% of the sites with an adequate or inadequate crown restoration respectively. The differences in distribution of marginal alveolar bone loss were highly significant (Chi square analysis, p = < 0.0001) for sites with intact, carious or restored sites, and for the presence or absence of contact loss, adequate amalgam or adequate crown.

Sequential manifestation of different forms of early-onset periodontitis. A case report.

Pathogenic bacteria constitute the primary extrinsic agent in the etiology of early onset periodontitis. However, the risk of developing periodontal disease is not equal for all individuals, suggesting host factors are involved in determining an individual's disease susceptibility. In this report, a case of an otherwise healthy female, who exhibited prepubertal periodontitis (PPP) at age 10, juvenile periodontitis (JP) at age 13, and rapidly progressive periodontitis (RPP) at age 29 years, is presented. Microbial, immunological, and genetic features of the case are presented. PPP, JP, and RPP are considered distinct disease entities, albeit with similar pathology and pathogenesis, yet all were manifest sequentially in the same individual. This report presents the idea that certain individuals are predisposed to early-onset periodontal diseases and the early identification of risk factors is important in the management of these individuals.

Histologic characteristics of the gingiva associated with the primary and permanent teeth of children.

The severity of the gingival inflammatory response to dental plaque increases with age, and it has been suggested that this phenomenon may be related to histological characteristics of the gingiva. The objective of this study was to compare the histological characteristics of the gingival tissues of primary teeth with that of permanent teeth in children. Prior to extraction, children were subjected to a period of thorough oral hygiene. Histological sections prepared from gingival biopsies were examined using the light microscope. One biopsy from each of seven primary and seven permanent teeth of 14 children, whose mean ages were 11.0 +/- 0.9 and 12.9 +/- 0.9 years respectively, was obtained. All sections exhibited clear signs of inflammation. Apical migration of the junctional epithelium onto the root surface was associated only with the primary teeth. Compared with the permanent teeth, the primary teeth were associated with a thicker junctional epithelium (P < 0.05), higher numbers of leukocytes in the connective tissue adjacent to the apical end of the junctional epithelium (P < 0.05), and a higher density of collagen fibers in the suboral epithelial connective tissue (P < 0.01). No significant differences were noted in the width of the free gingiva, thickness of the oral epithelium, or its keratinized layer. In conclusion, this study indicates significant differences in the microanatomy of the gingival tissues between primary and permanent teeth in children.

HLA A9 and B15 are associated with the generalized form, but not the localized form, of early-onset periodontal diseases.

HLA proteins are genetically determined, and account in part for individual immune response. Several studies have been performed seeking an association between HLA antigens and various forms of periodontitis with no conclusive results. The aim of the present study was to determine the frequency of HLA antigens of patients suffering from the localized (LJP) and the generalized (SGP) forms of early-onset periodontitis (EOP). Twenty-six EOP patients from the same ethnic group were studied in comparison to 113 race-matched controls. The EOP group included 11 LJP and 15 SGP patients. HLA-A9 and B15 antigens were found to be significantly elevated in the patient group. These differences were found to be due to the high frequency of A9 and B15 antigens in the SGP patients, with the LJP patient group showing no significant difference from the control group. The results are in agreement with previous studies in which A9 and B15 were found to be associated with EOP. However, previous studies did not differentiate between the localized and the generalized form of EOP. These results support the hypothesis that the generalized and the localized forms of EOP are under different genetic control.

Periodontal treatment needs, by CPITN, among employees of a Jerusalem hospital.

A survey, employing the Community Periodontal Index of Treatment Needs (CPITN), was conducted among 344 employees of a Jerusalem hospital. Of the population surveyed, 2.2 per cent demonstrated totally healthy mouths, 1.5 per cent had, at the worst, bleeding symptoms, 13.3 per cent had calculus, 53.4 per cent had 4-5 mm ('shallow' according to WHO) pockets and 29.6 per cent had deep pockets (6 mm or more) as their worst CPITN scores. Results revealed an average of 0.55 edentulous sextants, 0.68 healthy sextants, 0.87 sextants with bleeding symptoms, 1.36 with calculus, 1.95 with 4-5 mm pockets and 0.61 sextants with deep pockets. In general, females were healthier than males, had a significantly greater number of healthy sextants, less sextants with calculus and less sextants with deep pockets. A deterioration in periodontal health with age was evident, according to mean number of sextants per person by CPITN scores. Associations were also analysed between CPITN and demographic variables. Few significant associations were revealed. Based on FDI and WHO estimates, the calculated periodontal treatment needs for the hospital employees was found to be about 2 hours per person. Compared with data for other countries, as reported by the WHO, this status demands serious efforts to be made towards periodontal health promotion.

Structural and microbiological evaluation of a degradable sustained-release device for use in periodontal therapy.

Degradable protein matrices containing chlorhexidine were tested as intra-pocket drug delivery systems in the treatment of periodontal diseases. The properties of the device were mainly dependent upon the degree of cross linking in the matrix, which could be varied according to the preparative conditions. The degree of cross linking was determined by amino acid analysis based on the amount of free lysine in the protein. The release of chlorhexidine and of the plasticizer used in the preparation of the matrix were determined. The release of chlorhexidine from the matrix was prolonged for a period of 300 hours, and the release of plasticizer ceased after four hours. Limited clinical trials suggest that one of the degradable devices--that containing the highest amount of cross-linking--causes a significant reduction in the amount of perio-pathogenic bacteria following its insertion into the periodontal pockets of patients with periodontal disease.

Superoxide formation and chemiluminescence of peripheral polymorphonuclear leukocytes in rapidly progressive periodontitis patients.

Previous studies have indicated that in certain types of chronic inflammatory periodontal diseases, polymorphonuclear leucocytes (PMN) functions are impaired. In view of the damage oxygen free radicals may cause to the periodontal tissues, the present study focussed on superoxide (SO) formation and luminol-dependent chemiluminescence (LDCL) by peripheral PMN cells in rapidly progressive periodontitis patients (RPP). PMN cell preparations were stimulated by either opsonized bacteria or phorbol myristate acetate (PMA). The results indicate that PMN cells from RPP patients, stimulated by opsonized bacteria, have significantly enhanced SO formation and LDCL response as compared to healthy subjects. The hyperactivity was cell-associated. In the presence of PMA, no significant differences were detected between the groups. The results suggest that PMN cells from RPP patients are functionally activated, and produce elevated levels of oxygen radicals. These oxygen radicals may play a role in the pathogenesis of RPP.

A new degradable controlled release device for treatment of periodontal disease: in vitro release study.

The substantivity of a drug in the periodontal pocket is an important factor determining its effect on the subgingival flora. Therefore, one of the predominant factors in the development of a sustained release delivery device is the ability to control the rate of release of the drug. Previous studies have demonstrated the advantages of the local sustained release of chlorhexidine from nondegradable devices in the treatment of periodontal diseases. The aim of this study was to develop a degradable sustained release device composed of a cross-linked protein containing chlorhexidine as the therapeutic agent. The in vitro release profile of chlorhexidine from the degradable films was altered by the amount of chlorhexidine incorporated into the film, by the cross-link density of the polymer, and by the chlorhexidine salt used. The chlorhexidine in the final pharmaceutical preparation did not lose its antibacterial activity as was shown in an in vitro antibacterial test. This work demonstrates that the release of chlorhexidine from a degradable delivery system and the degradation of the matrix can be controlled by variation in the formulation. This presents a new dental drug delivery system that can be used as an adjunct in the treatment of periodontal diseases in the future. These studies enable us to choose the pharmaceutical formulations for clinical trials to be conducted testing the efficacy of this treatment modality.

Use of a metastabilized chlorous acid/chlorine dioxide formulation as a mouthrinse for plaque reduction.

A metastabilized chlorous acid/chlorine dioxide (MECA) formulation was used as a mouthwash in a group of 18 volunteers aged 20-27. Its effect on developing plaque and salivary bacterial count was tested. The trial was carried out over 33 days during which each subject used three different formulations of mouthwash: a high concentration (0.16% sodium chloride in an activating system), a low concentration (0.04% sodium chloride, comparably activated) and a placebo mouthwash (activating system alone). Each participant used each of the three formulations as the only means of oral hygiene for 5-day periods. Each experimental period was separated by 9 days during which the participants returned to their regular oral hygiene habits. The high concentration and low concentration groups showed a 34.5 and 13.5% reduction of dental plaque scores, respectively, compared with the placebo control group. This effect on the plaque index scores was not accompanied by any significant change in the number of salivary bacteria.

Apical migration of the junctional epithelium in the human primary dentition as a multifactorial phenomenon.

Apical migration of the gingival junctional epithelium and/or attachment loss in the human primary dentition have been reported in the literature. The findings of several histological, in vitro and radiographic studies are summarized and related to the etiology of this phenomenon. An hypothesis that apical migration of the junctional epithelium, in the human primary dentition, is the result of a combination of the qualitative characteristics of the inflammatory cell infiltrate, passive eruption and the shedding process is presented.

A radiographic study of interproximal alveolar bone crest between the primary molars in children.

This study establishes baseline data regarding the normal relationship between the cementoenamel junction and the alveolar crest in the primary dentition, using bitewing radiographs. Measurements greater than those presented in this study may indicate an early stage of periodontal disease in the primary dentition, a tendency of the patient to develop the disease, or a combination of these.

Clinical and microbiological effects of sustained release chlorhexidine in periodontal pockets.

Previous studies have shown that a 3-day exposure of the pocket flora to the sustained release of chlorhexidine significantly reduced the relative numbers of spirochetes and motile rods in periodontal pockets to negligible amounts. By 14 days post-treatment, their numbers had returned to pre-treatment levels. The present study extended the exposure time of the pocket flora to the sustained release of chlorhexidine in an attempt to prolong the suppression of the microbial flora for a clinically significant period of time. Clinical parameters were also studied. Sustained release devices (SRD) were inserted into 13 pockets from 8 patients. Pocket depth ranged between 5 and 8 mm. The SRD's were replaced every 3 days to give a total exposure of 9 days. Plaque index (PlI), bleeding on probing and pocket depth were measured, and bacterial samples taken for dark field microscopy and anaerobic culture. There was a marked decrease in the relative proportions of spirochetes and motile rods and the total anaerobic count post-treatment. Pocket depth was reduced in all 13 pockets. These results indicate that a prolonged exposure to chlorhexidine suppresses the pocket flora to negligible amounts and reduces pocket depth for up to 11 weeks post-treatment.

Sustained release device containing metronidazole for periodontal use.

The purpose of this study was to develop a sustained release device containing metronidazole for insertion within periodontal pockets and to examine the release kinetics in vitro and in vivo. Cast films of ethyl cellulose with or without polyethylene glycol, containing metronidazole, were prepared and exhibited sustained release. Release rate of metronidazole from the film was measured by means of a UV spectrophotometer, and kinetics of release in vitro was found to conform to Higuchi's diffusional model. The microbiological results proved that embedding metronidazole in ethyl cellulose film does not inhibit the biological activity. The release kinetics in vivo correlated with in vitro results, exhibiting a sustained release of metronidazole over a period of three days from 30% metronidazole with polyethylene glycol or 40% metronidazole in ethyl cellulose chloroform cast. This study demonstrates that, by embedding metronidazole in ethyl cellulose, it is possible to obtain sustained release of the drug within the periodontal pocket for three days.