Microbiology of periodontal disease in children and young adults

Periodontal inflammatory and microbial profiles in healthy young African Americans and Caucasians

AIM

This study aimed to compare microbial and inflammatory profiles in periodontally/systemically healthy African American (AA) and Caucasian (C) individuals.

MATERIALS AND METHODS

Thirty-seven C and 46 AA aged from 5 to 25 years were evaluated regarding periodontal disease, caries, microbial subgingival profile via 16-s sequencing, as well as salivary and gingival crevicular fluid (GCF) inflammatory profile via multiplex assay.

RESULTS

Greater probing depth percentage was detected in AA (p = .0075), while a higher percentage of caries index (p = .0069) and decayed, missing, filled teeth (DMFT) index (p = .0089) was observed in C, after adjusting for number of teeth, sex and age. Salivary levels of IL-6, IL-8 and TNFα were higher for C, whereas GCF levels of eotaxin, IL-12p40, IL-12p70, IL-2 and MIP-1α were higher in AA (p < .05). Different microbial profiles were observed between the races (p = .02). AA presented higher abundance of periodontopathogens (such as Tanerella forsythia, Treponema denticola, Filifactor alocis, among others), and C presented more caries-associated bacteria (such as Streptococcus mutans and Prevotella species). Bacillaceae and Lactobacillus species were associated with higher DMFT index, whereas Fusobacterium and Tanerella species with periodontal disease parameters.

CONCLUSIONS

A different inflammatory and bacterial profile was observed between healthy AA and C, which may predispose these races to higher susceptibility to specific oral diseases.

Evaluation of microbiome in primary and permanent dentition in grade C periodontitis in young individuals

BACKGROUND

The aim of the present study was to evaluate the subgingival microbiome in patients with grade C molar-incisor pattern periodontitis (C-MIP) affecting the primary or permanent dentitions.

METHODS

DNA was isolated from subgingival biofilm samples from diseased and healthy sites from 45 C-MIP patients and subjected to phylogenetic microarray analysis. C-MIP sites were compared between children affected in the primary to those affected in the permanent dentitions. Within-subject differences between C-MIP-affected sites and dentition-matched healthy sites were also evaluated.

RESULTS

C-MIP sites of subjects affected in the primary dentition showed partially overlapping but distinct microbial communities from C-MIP permanent dentition sites (p < 0.05). Differences were due to increased levels in primary C-MIP sites of certain species of the genera Capnocytophaga and Leptotrichia, while C-MIP permanent dentition sites showed higher prevalence of Filifactor alocis. Aggregatibacter actinomycetemcomitans (Aa) was among species seen in high prevalence and levels in both primary and permanent C-MIP sites. Moreover, both permanent and primary C-MIP sites showed distinct microbial communities when compared to dentition-matched healthy sites in the same subject (p < 0.01).

CONCLUSIONS

Primary and permanent teeth with C-MIP showed a dysbiotic microbiome, with children affected in the primary dentition showing a distinct profile from those affected in the permanent dentition. However, Aa was enriched in both primary and permanent diseased sites, confirming that this microorganism is implicated in C-MIP in both dentitions.

Is insufficient sleep duration a risk indicator for periodontal disease? A systematic review

OBJECTIVES

In this study, we conducted a systematic review and meta-analysis to assess whether people who achieved <7 h of sleep were more likely to develop periodontal disease (PD).

SOURCES

We executed electronic searches in the PubMed, EMBASE and Cochrane Library, as well as a manual search of articles published by leading journals in related fields, for observational studies, published in English from 1 January 1966 to 31 March 2021.which evaluated the relationship between sleep duration and PD. The Agency for Healthcare Research and Quality (AHRQ) quality evaluation scale was used for the cross-sectional studies, and the random effects model was used to summarize the effect sizes in the included studies with a 95% confidence interval (CI).

RESULTS

A total of six cross-sectional studies met the inclusion criteria, totaling 107,777 participants, of which 69,773 had PD. The results of the present indicated that shorter sleep duration (<7 h) is significantly associated with PD (Odd ratio [OR], 1.19; 95% CI, 1.16-1.23; p < 0.001; I² , 0.0%, I² interval, 0%-75%). The strength of the sensitivity analysis and cumulative meta-analysis confirmed the reliability of the results.

CONCLUSION

Although the inclusion of only six studies makes it difficult to explore whether there is a publication bias, we found that insufficient sleep duration was closely related to PD, and we therefore speculated that getting enough sleep may help prevent PD.

A comparative study on periodontitis and periodontitis-associated bacteria in Somali and non-Somali children and adolescents living in Trollhättan, Sweden

The reported prevalence of periodontitis in children and adolescents varies considerably between populations globally. This cross-sectional study compares clinical and microbiological findings on 83 Somali immigrants and 96 non-Somali children aged 10-17 years old living in Trollhättan, Sweden. The clinical examination included registration of bleeding on probing, plaque, and calculus on incisors and first molars. The distance between cemento-enamel junction and bone level was measured on bitewing radiographs. Pooled microbiological samples (1 μL) were taken from the mesial surface of 16, 11, 31, 36, and analyzed by culture and real-time polymerase chain reaction for seven periodontal associated bacterial species. The Somali participants had poorer oral hygiene and more bleeding, plaque, and calculus. Ten of the Somali but none of the non-Somali participants showed periodontal breakdown (radiographical bone loss > 3 mm), corresponding to a prevalence of 12% (95% CI: 5.9, 21.0%). The presence of A. actinomycetemcomitans was almost exclusively associated with Somali participants. Further, the JP2 clone was found in five Somalis (including two periodontitis cases) confirming the association of this clone with African populations. The Somali group showed significantly higher frequencies and numbers of Porphyromonas gingivalis and Treponema denticola, implying a mature and adult type of subgingival microbiota.

Electrospun PLA Fibers Containing Metronidazole for Periodontal Disease

Purpose

Electrospun PLA fiber devices were investigated in the form of fiber mats and disks. Metronidazole was used as an active agent; its concentration was 12.2 and 25.7 wt% in the devices.

Methods

The structure was studied by X-ray diffraction and scanning electron microscopy, drug release by dissolution measurements, while the antimicrobial efficiency was tested on five bacterial strains.

Results

The XRD study showed that the polymer was partially crystalline in both devices, but a part of metronidazole precipitated and was in the form of crystals among and within the fibers. Liquid penetration and dissolution were different in the two devices, they were faster in disks and slower in fiber mats, due to the morphology of the device and the action of capillary forces. Disks released the drug much faster than fiber mats. Although the release study indicated fast drug dissolution, the concentration achieved a plateau value in 24 hrs for the disks; the inhibition effect lasted much longer, 13 days for bacteria sensitive to metronidazole. The longer inhibition period could be explained by the slower diffusion of metronidazole located inside the fibers of the device.

Conclusion

The results suggest that the devices may be effective in the treatment of periodontitis.

Combination of Zinc Hyaluronate and Metronidazole in a Lipid-Based Drug Delivery System for the Treatment of Periodontitis

Background: Despite being a highly prevalent disease and a possible contributor to adult tooth loss, periodontitis possesses no well-established therapy. The aim of the recent study was the development and evaluation of a mucoadhesive monophase lipid formulation for the sustained local delivery of amoxicillin, metronidazole, and/or zinc hyaluronate or gluconate. Methods: To investigate our formulations, differential scanning calorimetry, X-ray diffraction, swelling, erosion, mucoadhesivity, drug release, and antimicrobial measurements were performed. Results: Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) results show that the loaded drugs are in a suspended form, the softening of the formulations starts at body temperature, but a part remains solid, providing sustained release. Swelling of the lipid compositions is affected by the hydrophilic components, their concentration, and the strength of the coherent lipid structure, while their erosion is impacted by the emulsification of melted lipid components. Conclusions: Results of drug release and antimicrobial effectiveness measurements show that a sustained release may be obtained. Amoxicillin had higher effectiveness against oral pathogens than metronidazole or zinc hyaluronate alone, but the combination of the two latter could provide similar effectiveness to amoxicillin. The applied mucoadhesive polymer may affect adhesivity, drug release through the swelling mechanism, and antimicrobial effect as well.

Caries and Periodontitis: Contesting the Conventional Wisdom on Their Aetiology

We review the literature on the oral microbiome and the role of the microbiota in the development of dental caries and periodontitis. While most research has been focused on identifying one or more specific determinants of these diseases, the results have provided limited predictive value and have not been able to explain the variation in the distribution of these diseases observed in epidemiological or clinical studies. Drawing on existing knowledge about the nature of the oral microbiota, we suggest that a stochastic model based on the Weiner process provides simple and parsimonious explanations for the pathogenesis of both caries and periodontitis, making few assumptions, and providing explanations for phenomena that have hitherto proved difficult, or have required complex arguments, to explain. These diseases occur as the result of the dental hard tissues and periodontal tissues integrating the random "noise" caused by normal metabolic activities of commensal microorganisms in the dental biofilm. The processes that result in the progression and regression of caries and periodontitis may be considered as "natural," rather than pathological, even if, when left unchecked over long periods of time, they can result in the development of pathologies. The likelihood of progression or regression can be influenced by other determinants, but these processes will nevertheless occur in the absence of such influences. The distributional characteristics of the model approximate the findings of epidemiological studies indicating that, for both caries and periodontitis, there will be few sites affected in the early period after the eruption of the permanent dentition, but in those older there is an almost linear relationship with increasing age; furthermore, the longer a site survives without being affected, the less likely that it will be affected. We discuss the clinical and public health importance of these findings.

Non-Surgical Therapy Reduces Presence of JP2 Clone in Localized Aggressive Periodontitis

BACKGROUND

Previous studies have provided substantial evidence of the association of Aggregatibacter actinomycetemcomitans, and its highly leukotoxic JP2 genotype, with localized aggressive periodontitis (LAgP). The present study aims to evaluate presence of JP2 in individuals with LAgP after periodontal treatment.

METHODS

Sixty African-American patients with LAgP, aged 5 to 25 years, were examined. At baseline, probing depth (PD), clinical attachment level (CAL), bleeding on probing, and plaque index were measured, and subgingival plaque was collected from LAgP diseased and healthy sites for each participant. Patients received whole-mouth ultrasonic debridement, scaling and root planing, and a 7-day prescription of amoxicillin and metronidazole. Participants were reevaluated and resampled and received regular maintenance therapy at 3, 6, and 12 months after treatment. Polymerase chain reaction was used to detect presence of the JP2 genotype before and after treatment.

RESULTS

At baseline, the JP2 sequence was identified in 75% of LAgP diseased sites and in 56.67% of healthy sites. At 3, 6, and 12 months after treatment, the number of patients was 40, 31, and 31, respectively, and JP2 detection decreased to 17.5%, 6.45%, and 3.23%, respectively, in diseased sites (P <0.001) and to 2.5%, 3.23%, and 0%, respectively, in healthy sites (P <0.001). Clinical parameters of disease were also significantly reduced after therapy (P <0.001). Additionally, significant correlations were observed between JP2 presence and mean PD (P <0.002) and CAL (P <0.001), after therapy.

CONCLUSION

Periodontal therapy was successful in reducing clinical parameters of LAgP and subgingival presence of JP2 in diseased and healthy sites.

Role of oral and gut microbiome in nitric oxide-mediated colon motility

Periodontal disease (PD), a severe form of gum disease, is among the most prevalent chronic infection in humans and is associated with complex microbial synergistic dysbiosis in the subgingival cavity. The immune system of the body interacts with the microbes as the plaque extends and propagates below the gingival sulcus. Once bacteria reach the gingival sulcus, it can enter the blood stream and affect various areas of the human body. The polymicrobial nature of periodontal disease, if left untreated, promotes chronic inflammation, not only within the oral cavity, but also throughout the human body. Alterations seen in the concentrations of healthy gut microbiota may lead to systemic alterations, such as gut motility disorders, high blood pressure, and atherosclerosis. Although gut microbiome has been shown to play a vital role in intestinal motility functions, the role of oral bacteria in this setting remains to be investigated. It is unclear whether oral microbial DNA is present in the large intestine and, if so, whether it alters the gut microbiome. In addition, polybacterial infection induced PD reduced nitric oxide (NO) synthesis and antioxidant enzymes in rodent colon. In this review, we will discuss the interactions between oral and gut microbiome, specifics of how the oral microbiome may modulate the activities of the gut microbiome, and possible ramifications of these alterations.

Aggregatibacter actinomycetemcomitans in African Americans with Localized Aggressive Periodontitis

This study aims to investigate the prevalence of the highly leukotoxic JP2 sequence versus the minimally leukotoxic non-JP2 sequence of Aggregatibacter actinomycetemcomitans within a cohort of 180 young African Americans, with and without localized aggressive periodontitis (LAP), in north Florida. The study included patients aged 5 to 25 y: 60 LAP patients, 60 healthy siblings (HS), and 60 unrelated healthy controls (HC). Subgingival plaque was collected from LAP sites-diseased (PD ≥5 mm with bleeding on probing) and healthy (PD ≤3 mm with no bleeding on probing)-and from healthy sites of HS and HC. Plaque DNA was extracted and analyzed by polymerase chain reaction for the detection of the JP2 and non-JP2 sequences of A. actinomycetemcomitans. Overall, 90 (50%) subjects tested positive for the JP2 sequence. Fifty (83.33%) LAP subjects were carriers of the highly leukotoxic JP2 sequence, detected in 45 (75%) diseased sites and 34 (56.67%) healthy sites. Additionally, JP2 carriage was found in 16 HS (26.67%) and 24 HC (40%; P < 0.0001, among groups). The non-JP2 sequence was detected in 26 (14.44%) total subjects: 17 (28.33%) LAP patients detected in equal amounts of diseased and healthy sites (n = 11, 18.33%), 6 (10%) HS sites, and 3 (5%) HC sites (P < 0.05, among groups). The JP2 sequence was strongly associated with LAP-diseased sites in young African Americans, significantly more so than the non-JP2 (ClinicalTrials.gov NCT01330719). Knowledge Transfer Statement: Clinicians may use the results of this study to identify susceptible individuals to aggressive periodontitis, potentially leading to more appropriate selection of therapeutic choices.

Long-term clinical response to treatment and maintenance of localized aggressive periodontitis: a cohort study

AIM

To evaluate long-term clinical response to periodontal therapy and maintenance in localized aggressive periodontitis (LAP).

MATERIALS AND METHODS

One hundred forty-one African Americans diagnosed with LAP, aged 5-25 years, were enrolled. Patients underwent periodontal mechanical debridement plus 1 week of amoxicillin/metronidazole. Mechanical therapy was repeated as needed and clinical parameters were recorded at baseline, 3, 6, 12, 18 and 24 months, and two additional annual follow-up visits after treatment. Radiographs from primary dentition of patients with LAP in permanent dentition, and additional healthy siblings (HS) were analysed retrospectively.

RESULTS

Periodontal therapy significantly improved probing depth and clinical attachment level up to 4 years (mean reductions: 2.18 ± 1.03 and 2.80 ± 1.43 mm, respectively). Percentage of affected sites was reduced at all time points and maintained up to 4 years. Non-compliance with antibiotics/appointments negatively affected the treatment response. Ninety per cent of LAP patients in permanent dentition and 32% of HS presented radiographic bone loss in primary dentition.

CONCLUSIONS

Mechanical debridement with 1 week of systemic antibiotics along with proper periodontal maintenance was effective in the treatment and successful maintenance of LAP for up to 4 years. LAP in permanent dentition may be preceded in the primary dentition. Clinicaltrials.gov #NCT01330719.

Nonsyndromic localized aggressive periodontitis of primary dentition: A rare case report

Periodontitis is an inflammatory disease of the gingiva and tissues of the periodontium. It is characterized by pocket formation and destruction of supporting alveolar bone. Periodontal diseases of aggressive nature are not very common in children. They are usually associated with systemic conditions. The present case report is of a 5-year-old male child who reported with rapid attachment loss and bony defects of the gingiva and supporting structures. His family and medical history gave no contribution for the diagnosis. Blood investigations did not reveal any abnormality. The microbial examination of culture revealed the presence of periodontal pathogen Aggregatibacter actinomycetemcomitans. The treatment objective in the present case was to prevent the further progress of the condition, restore esthetic and function in the child which would psychologically benefit the child.

Management of apicomarginal defect in esthetic region associated with a tooth with anomalies

Tooth related factors such as palatoradicular groove can be one of the causes for localized periodontal destruction. Such pathological process may result in apicomarginal defect along with inflammation of pulp. This creates challenging situation which clinician must be capable of performing advanced periodontal regenerative procedures for the successful management. This case report discusses clinical management of apicomarginal defect associated with extensive periradicular destruction in a maxillary lateral incisor, along with histopathologic aspect of the lesion.

Calcium Regulates the Activity and Structural Stability of Tpr, a Bacterial Calpain-like Peptidase

Porphyromonas gingivalis is a peptide-fermenting asaccharolytic periodontal pathogen. Its genome contains several genes encoding cysteine peptidases other than gingipains. One of these genes (PG1055) encodes a protein called Tpr (thiol protease) that has sequence similarity to cysteine peptidases of the papain and calpain families. In this study we biochemically characterize Tpr. We found that the 55-kDa Tpr inactive zymogen proteolytically processes itself into active forms of 48, 37, and 33 kDa via sequential truncations at the N terminus. These processed molecular forms of Tpr are associated with the bacterial outer membrane where they are likely responsible for the generation of metabolic peptides required for survival of the pathogen. Both autoprocessing and activity were dependent on calcium concentrations >1 mm, consistent with the protein's activity within the intestinal and inflammatory milieus. Calcium also stabilized the Tpr structure and rendered the protein fully resistant to proteolytic degradation by gingipains. Together, our findings suggest that Tpr is an example of a bacterial calpain, a calcium-responsive peptidase that may generate substrates required for the peptide-fermenting metabolism of P. gingivalis. Aside from nutrient generation, Tpr may also be involved in evasion of host immune response through degradation of the antimicrobial peptide LL-37 and complement proteins C3, C4, and C5. Taken together, these results indicate that Tpr likely represents an important pathogenesis factor for P. gingivalis.

Comparison of the Oral Microbiomes of Canines and Their Owners Using Next-Generation Sequencing

The oral microbiome, which is closely associated with many diseases, and the resident pathogenic oral bacteria, which can be transferred by close physical contact, are important public health considerations. Although the dog is the most common companion animal, the composition of the canine oral microbiome, which may include human pathogenic bacteria, and its relationship with that of their owners are unclear. In this study, 16S rDNA pyrosequencing was used to compare the oral microbiomes of 10 dogs and their owners and to identify zoonotic pathogens. Pyrosequencing revealed 246 operational taxonomic units in the 10 samples, representing 57 genera from eight bacterial phyla. Firmicutes (57.6%), Proteobacteria (21.6%), Bacteroidetes (9.8%), Actinobacteria (7.1%), and Fusobacteria (3.9%) were the predominant phyla in the human oral samples, whereas Proteobacteria (25.7%), Actinobacteria (21%), Bacteroidetes (19.7%), Firmicutes (19.3%), and Fusobacteria (12.3%) were predominant in the canine oral samples. The predominant genera in the human samples were Streptococcus (43.9%), Neisseria (10.3%), Haemophilus (9.6%), Prevotella (8.4%), and Veillonella (8.1%), whereas the predominant genera in the canine samples were Actinomyces (17.2%), Unknown (16.8), Porphyromonas (14.8), Fusobacterium (11.8), and Neisseria (7.2%). The oral microbiomes of dogs and their owners were appreciably different, and similarity in the microbiomes of canines and their owners was not correlated with residing in the same household. Oral-to-oral transfer of Neisseria shayeganii, Porphyromonas canigingivalis, Tannerella forsythia, and Streptococcus minor from dogs to humans was suspected. The finding of potentially zoonotic and periodontopathic bacteria in the canine oral microbiome may be a public health concern.

Peptidoglycan Induces the Production of Interleukin-8 via Calcium Signaling in Human Gingival Epithelium

The etiology of periodontal disease is multifactorial. Exogenous stimuli such as bacterial pathogens can interact with toll-like receptors to activate intracellular calcium signaling in gingival epithelium and other tissues. The triggering of calcium signaling induces the secretion of pro-inflammatory cytokines such as interleukin-8 as part of the inflammatory response; however, the exact mechanism of calcium signaling induced by bacterial toxins when gingival epithelial cells are exposed to pathogens is unclear. Here, we investigate calcium signaling induced by bacteria and expression of inflammatory cytokines in human gingival epithelial cells. We found that peptidoglycan, a constituent of gram-positive bacteria and an agonist of toll-like receptor 2, increases intracellular calcium in a concentration-dependent manner. Peptidoglycan-induced calcium signaling was abolished by treatment with blockers of phospholipase C (U73122), inositol 1,4,5-trisphosphate receptors, indicating the release of calcium from intracellular calcium stores. Peptidoglycan-mediated interleukin-8 expression was blocked by U73122 and 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis (acetoxymethyl ester). Moreover, interleukin-8 expression was induced by thapsigargin, a selective inhibitor of the sarco/endoplasmic reticulum calcium ATPase, when thapsigargin was treated alone or co-treated with peptidoglycan. These results suggest that the gram-positive bacterial toxin peptidoglycan induces calcium signaling via the phospholipase C/inositol 1,4,5-trisphosphate pathway, and that increased interleukin-8 expression is mediated by intracellular calcium levels in human gingival epithelial cells.

Rare case of generalised aggressive periodontitis in the primary dentition

BACKGROUND

Generalised aggressive periodontitis (AP) in the prepubescent age is an exceptionally rare disease in the primary dentition of otherwise healthy children. Characteristics of AP are gingival inflammation, deep periodontal pockets, bone loss, tooth mobility and even tooth loss. The most common way of treating this disease is the extraction of all the involved primary teeth.

CASE REPORT

A 4-year-old girl presented with signs of severe gingival inflammation. Clinical examination revealed deep pockets, increased tooth mobility and bone loss. Microbiological testing revealed the presence of a typical periopathogenic flora consisting of Aggregatibacter actinomycetemcomitans and the typical members of the red complex (Porphyromonas gingivalis, Prevotella intermedia and Treponema denticola). The patient underwent tooth extraction of all primary teeth except the primary canines, followed by thorough root debridement and treatment with systemic antibiotics (amoxicillin plus metronidazole).

FOLLOW-UP

Regular clinical and microbiological examinations over 4 years showed no signs of recurrence of a periodontitis, even in the erupted permanent teeth.

CONCLUSION

Early diagnosis and consequent early treatment of aggressive periodontitis can stop the disease and therefore avoid the development of a periodontal disease in the permanent dentition. A close collaboration between specialists of different disciplines is required for a favourable outcome.

Protease-dependent mechanisms of complement evasion by bacterial pathogens

The human immune system has evolved a variety of mechanisms for the primary task of neutralizing and eliminating microbial intruders. As the first line of defense, the complement system is responsible for rapid recognition and opsonization of bacteria, presentation to phagocytes and bacterial cell killing by direct lysis. All successful human pathogens have mechanisms of circumventing the antibacterial activity of the complement system and escaping this stage of the immune response. One of the ways in which pathogens achieve this is the deployment of proteases. Based on the increasing number of recent publications in this area, it appears that proteolytic inactivation of the antibacterial activities of the complement system is a common strategy of avoiding targeting by this arm of host innate immune defense. In this review, we focus on those bacteria that deploy proteases capable of degrading complement system components into non-functional fragments, thus impairing complement-dependent antibacterial activity and facilitating pathogen survival inside the host.

A combination of clinical and microbiological management of generalized aggressive periodontitis in primary teeth. A case report

BACKGROUND

Generalized aggressive periodontitis (GAP) in primary teeth is a rare periodontal disease that occurs during or soon after eruption of the primary teeth. An association with systemic diseases is a possibility.

CASE REPORT

A 4-year-old Brazilian girl presented with GAP involving the entire primary dentition. The patient and her parents and sister were subjected to microbiological testing to identify the microorganisms involved in the disease. The patient underwent tooth extraction to eradicate the disease and received a prosthesis for the restoration of masticatory function. After the permanent teeth erupted, fixed orthodontic appliances were place to restore dental arch form and occlusion.

CONCLUSIONS

The results show the importance of an early diagnosis of GAP and of a multidisciplinary approach involving laboratory and clinical management to treat the disease and to restore masticatory function, providing a better quality of life for patients.

Deep sequencing of the oral microbiome reveals signatures of periodontal disease

The oral microbiome, the complex ecosystem of microbes inhabiting the human mouth, harbors several thousands of bacterial types. The proliferation of pathogenic bacteria within the mouth gives rise to periodontitis, an inflammatory disease known to also constitute a risk factor for cardiovascular disease. While much is known about individual species associated with pathogenesis, the system-level mechanisms underlying the transition from health to disease are still poorly understood. Through the sequencing of the 16S rRNA gene and of whole community DNA we provide a glimpse at the global genetic, metabolic, and ecological changes associated with periodontitis in 15 subgingival plaque samples, four from each of two periodontitis patients, and the remaining samples from three healthy individuals. We also demonstrate the power of whole-metagenome sequencing approaches in characterizing the genomes of key players in the oral microbiome, including an unculturable TM7 organism. We reveal the disease microbiome to be enriched in virulence factors, and adapted to a parasitic lifestyle that takes advantage of the disrupted host homeostasis. Furthermore, diseased samples share a common structure that was not found in completely healthy samples, suggesting that the disease state may occupy a narrow region within the space of possible configurations of the oral microbiome. Our pilot study demonstrates the power of high-throughput sequencing as a tool for understanding the role of the oral microbiome in periodontal disease. Despite a modest level of sequencing (~2 lanes Illumina 76 bp PE) and high human DNA contamination (up to ~90%) we were able to partially reconstruct several oral microbes and to preliminarily characterize some systems-level differences between the healthy and diseased oral microbiomes.

Acquisition of complement inhibitor serine protease factor I and its cofactors C4b-binding protein and factor H by Prevotella intermedia

Infection with the Gram-negative pathogen Prevotella intermedia gives rise to periodontitis and a growing number of studies implies an association of P. intermedia with rheumatoid arthritis. The serine protease Factor I (FI) is the central inhibitor of complement degrading complement components C3b and C4b in the presence of cofactors such as C4b-binding protein (C4BP) and Factor H (FH). Yet, the significance of complement inhibitor acquisition in P. intermedia infection and FI binding by Gram-negative pathogens has not been addressed. Here we show that P. intermedia isolates bound purified FI as well as FI directly from heat-inactivated human serum. FI bound to bacteria retained its serine protease activity as shown in degradation experiments with ¹²⁵I-labeled C4b. Since FI requires cofactors for its activity we also investigated the binding of purified cofactors C4BP and FH and found acquisition of both proteins, which retained their activity in FI mediated degradation of C3b and C4b. We propose that FI binding by P. intermedia represents a new mechanism contributing to complement evasion by a Gram-negative bacterial pathogen associated with chronic diseases.

Perialveolar bacterial microbiota and bacteraemia after dental alveolitis in adult rats that had been subjected to neonatal malnutrition

The aim of the present study was to analyse the bacteriological factors during the process of dental alveolitis, relating it to a higher incidence of bacteraemia in adult rats subjected to neonatal malnutrition. We used forty male Wistar rats, suckled by mothers fed a diet during lactation containing 17 % protein in the nourished group (N) or 8 % protein in the undernourished group (UN). After weaning, the animals were given the Labina standard diet. After 90 d, these animals underwent upper right incisor extraction and induction of alveolitis. The oral microbiota was obtained using a swab and blood culture through venous blood. These procedures were performed before the extraction, 5 min after extraction, on the 21st day after alveolitis for groups N-21 and UN-21 and on the 28th day after alveolitis for groups N-28 and UN-28. Data were expressed as means and standard deviations for parametric data, and as medians and interquartile intervals for non-parametric data. Statistical significance was considered by assuming a critical level of 5 %. Before and after extraction, lower bacterial growth was observed per colony-forming unit (CFU) in the perialveolar region of the upper right incisors of undernourished animals, while the opposite was true after alveolitis, when a larger number of CFU was observed in these animals. The percentage of positive blood cultures obtained after alveolitis was greater in the undernourished animals. The present study thus demonstrated the influence of neonatal malnutrition in the perialveolar microbiota and in the development of bacteraemia after dental alveolitis.

Can oral pathogens influence allergic disease?

The hygiene hypothesis contends that fewer opportunities for infections and microbial exposures have resulted in more widespread asthma and atopic disease. Consistent with that hypothesis, decreases in infectious oral diseases over the past half century have coincided with increases in the prevalence of asthma and other allergic diseases. This observation has led some researchers to speculate that exposures to oral bacteria, including pathogens associated with periodontal diseases, such as gingivitis and periodontitis, might play a protective role in the development of asthma and allergy. Colonization of the oral cavity with bacteria, including some species of periodontal pathogens, begins shortly after birth, and the detection of serum antibodies to oral pathogens in early childhood provides evidence of an early immune response to these bacteria. Current knowledge of the immune response to oral bacteria and the immunologic pathogenesis of periodontal diseases suggests biologically plausible mechanisms by which oral pathogens could influence the risk of allergic disease. However, studies investigating the association between oral pathogen exposures and allergic disease are few in number and limited by cross-sectional or case-control design, exclusion of young children, and use of surrogate measures of oral bacterial colonization. Additional studies, particularly well-designed case-control studies among very young children and prospective birth cohort studies, are needed.

A microbiological study in relation to the presence of caries and calculus

OBJECTIVE

To examine whether oral microflora in individuals with caries differs from that of individuals with calculus in Thai adolescents with poor oral hygiene.

MATERIAL AND METHODS

One hundred 13-year-old schoolchildren from Southern Thailand were examined for the presence of caries, calculus and plaque and saliva pH was also determined. Saliva samples were analysed by culture and approximal supragingival plaque samples were analysed with the DNA-DNA hybridization method ('checkerboard').

RESULTS

Among the 100 children, mean DMFS was 3.43 [standard deviation (SD) 2.82] and 90% had calculus. The correlation between DMFS and the calculus index was 0.064. A total of 36 children were caries-free and 56 had calculus including teeth other than those in the lower anterior region (calculus score > or =3). A total of 23 caries-free children with a high calculus score (> or =3) were compared with 22 children with the highest DMFS [mean 11.19 (SD 5.58)] and a calculus score < 3. No significant difference was obtained for saliva and plaque pH. The salivary levels of mutans Streptococci and Lactobacilli were low. Significantly more children in the caries group had high levels of glycolytic Prevotella nigrescens and Filifactor alocis in plaque compared with the calculus group. Calculus cases had a significantly higher total viable count in saliva.

CONCLUSIONS

There was no inverse correlation between the presence of caries and calculus at a population level and a high calculus score only marginally reduced the individual likelihood of having caries. Several glycolytic bacteria were related to caries, while no specific bacteria could be related to calculus formation. Calculus seemed to be more closely related to poor oral hygiene.

Interpain A, a cysteine proteinase from Prevotella intermedia, inhibits complement by degrading complement factor C3

Periodontitis is an inflammatory disease of the supporting structures of the teeth caused by, among other pathogens, Prevotella intermedia. Many strains of P. intermedia are resistant to killing by the human complement system, which is present at up to 70% of serum concentration in gingival crevicular fluid. Incubation of human serum with recombinant cysteine protease of P. intermedia (interpain A) resulted in a drastic decrease in bactericidal activity of the serum. Furthermore, a clinical strain 59 expressing interpain A was more serum-resistant than another clinical strain 57, which did not express interpain A, as determined by Western blotting. Moreover, in the presence of the cysteine protease inhibitor E64, the killing of strain 59 by human serum was enhanced. Importantly, we found that the majority of P. intermedia strains isolated from chronic and aggressive periodontitis carry and express the interpain A gene. The protective effect of interpain A against serum bactericidal activity was found to be attributable to its ability to inhibit all three complement pathways through the efficient degradation of the alpha-chain of C3 -- the major complement factor common to all three pathways. P. intermedia has been known to co-aggregate with P. gingivalis, which produce gingipains to efficiently degrade complement factors. Here, interpain A was found to have a synergistic effect with gingipains on complement degradation. In addition, interpain A was able to activate the C1 complex in serum, causing deposition of C1q on inert and bacterial surfaces, which may be important at initial stages of infection when local inflammatory reaction may be beneficial for a pathogen. Taken together, the newly characterized interpain A proteinase appears to be an important virulence factor of P. intermedia.

Periodontal pathogen levels in adolescents before, during, and after fixed orthodontic appliance therapy

INTRODUCTION

This purpose of this study was to document and investigate changes in periodontal pathogen levels before, during, and after orthodontic treatment in adolescents.

METHODS

DNA gene probe analysis was used to quantify the levels of 8 periodontal pathogens before, during, and after treatment with fixed orthodontic appliances in 190 concurrently treated adolescent orthodontic patients. The 8 pathogens examined were Actinobacillus actinomycetemcomitans (AA), Porphyromonas gingivalis (PG), Prevotella intermedia (PI), Tannerella forsythia (TF), Eikenella corrodens (EC), Fusobacterium nucleatum (FN), Treponema denticola (TD), and Campylobacter rectus (CR). Chi-square tests were used to determine whether the percentages of subjects with high counts significantly changed over time. Logistic regression analyses were also performed to derive the relative risk of higher counts of pathogenic bacteria with fixed appliances at the various time intervals studied.

RESULTS

For 6 (PI, TF, EC, FN, TD, CR) of the 8 pathogens, the percentages of subjects with high pathogen counts increased significantly after 6 months of fixed appliance treatment, but these returned to pretreatment levels by 12 months of orthodontic treatment. No pathogen level was significantly higher after 12 months of orthodontic treatment, and orthodontic treatment was found to be significantly protective for half of the pathogens (EC, FN, TD, CR) posttreatment.

CONCLUSIONS

Orthodontic treatment with fixed appliances does not increase the risk of high levels of these periodontal pathogens.

The inhibitory effects of naringin on the growth of periodontal pathogens in vitro

Naringin is a flavonoid that is commonly found in grapefruits. The objective of this study was to evaluate the effects of naringin on the growth of periodontal pathogens such as A. actinomycetemcomitans and P. gingivalis in vitro. For comparison, the effects of naringin on several oral microbes were also studied. Different concentrations of naringin solution were added to calibrated suspensions of A. actinomycetemcomitans and P. gingivalis. All the suspensions were incubated for 3, 6 and 24 h in an anaerobic chamber at 37 degrees C. At each time point, selected dilutions from each culture broth were plated on blood agar plates. Colonies recovered on blood agar were visually counted on days 3 and 5, respectively. A. actinomycetemcomitans showed a significant decrease (p < 0.05) in viable counts after 3 h when naringin was added at baseline. P. gingivalis also showed a marked growth reduction in the presence of naringin, and no colony forming units could be observed after 24 h. Naringin also had an inhibitory effect against all bacteria and yeasts tested. The results suggest that naringin possesses significant antimicrobial properties on periodontal pathogens in vitro. It also has an inhibitory effect on some common oral microorganisms in low concentrations.

Membrane morphology and leukotoxin secretion are associated with a novel membrane protein of Aggregatibacter actinomycetemcomitans

Gram-negative bacteria display either a flat or an irregular outer membrane. The periodontal pathogen Aggregatibacter (Actinobacillus) actinomycetemcomitans has an irregular outer membrane. We have identified a gene that is associated with the biogenesis of this morphology. The gene is part of a three-gene operon and codes for a 141-kDa protein designated morphogenesis protein C (MorC), which is conserved in several gram-negative bacteria including Haemophilus influenzae and Pasteurella multocida. Insertional inactivation of this gene resulted in the conversion of an irregularly shaped membrane to a flat membrane. Associated with this morphological change were the autoaggregation of the bacteria during planktonic growth and a concomitant increase in the surface hydrophobicity of the bacterium. The absence of MorC also resulted in the loss of the secretion of leukotoxin but not the ltxA transcription. Our findings suggest that MorC is critical for membrane morphology and leukotoxin secretion in A. actinomycetemcomitans.

Colonization pattern of periodontal bacteria in Japanese children and their mothers

BACKGROUND AND OBJECTIVE

The purpose of this study was to determine the time of infection by anaerobic gram-negative rods associated with periodontal disease, and to clarify their transmission from mother to child.

MATERIAL AND METHODS

Seventy-eight Japanese children (including 10 siblings), aged from 3 to 9 years, and 68 mothers, were enrolled in this study. Colonization by 11 periodontal bacterial species was determined using polymerase chain reaction amplification of samples of subgingival plaque obtained from the children and their mothers.

RESULTS

The detection rates of Porphyromonas gingivalis, Tannerella forsythensis and Treponema denticola increased in children after the age of 6 years. We found a high consistency in colonization by P. gingivalis, T. denticola, Prevotella intermedia and Prevotella nigrescens in 9 of the 10 siblings. The average number of bacterial species in plaque samples harboring Fusobacterium nucleatum and/or Fusobacterium periodonticum was significantly greater than in those without, in both children and mothers. Kappa statistical analysis revealed that the detection of Capnocytophaga gingivalis, Capnocytophaga ochracea, Campylobacter rectus and T. denticola in children was consistent with that in the mother.

CONCLUSION

Periodontal bacterial colonization in Japanese children increased with age and was associated with F. nucleatum and/or periodonticum, and the bacterial flora in children was similar to that in their mothers.

Production of antagonistic substance by Eikenella corrodens isolated from the oral cavity of human beings with and without periodontal disease

AIMS

Antagonistic abilities may confer ecological advantages for micro-organisms in competitive ecosystems. However, reports regarding this phenomenon in Eikenella corrodens are not available.

METHODS AND RESULTS

Nineteen E. corrodens strains, isolated from the oral cavity of human beings without periodontal disease (n = 5) and with aggressive (n = 9) and chronic (n = 5) periodontitis, as well as a reference strain (E. corrodens ATCC23834), were evaluated for antagonistic activity. The following indicators were used: Porphyromonas gingivalis FDC381, Prevotella intermedia ATCC25611, Actinomyces israelii ATCC12102, Eubacterium lentum ATCC25559, Peptostreptococcus anaerobius ATCC27337, Actinobacillus actinomycetemcomitans FDCY4, Fusobacterium nucleatum ATCC10953, Streptococcus sanguinis ATCC10557, Streptococcus uberis ATCC9927, Streptococcus mutans IM/UFRJ, Staphylococcus aureus ATCC33591 and Candida albicans ATCC18804. All the strains showed antagonism against at least one of the indicator strains. This phenomenon was more frequently observed for strains isolated from patients with chronic periodontitis (36.4%), than those from healthy subjects (20.6%) and those with aggressive periodontitis (10.8%).

CONCLUSIONS

The heterogeneous antagonistic spectrum exhibited by E. corrodens isolates suggests their ability to produce more than one antagonistic substance, whose ecological relevance is yet to be demonstrated.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first description of antagonistic compound production by E. corrodens and its relationships with the clinical status of the patients.

Desnutrição neonatal e microbiota normal da cavidade oral em ratos

OBJETIVO: Avaliar a influência da desnutrição neonatal sobre o padrão e o crescimento de bactérias aeróbias, da microbiota normal da cavidade oral, em ratos Wistar adultos. MÉTODOS: O material da cavidade oral foi coletado através de swabs embebidos em 40µL de solução salina estéril e colocados em tubos estéreis contendo 960µL de brain heart infusion. Posteriormente, fez-se homogeneização de cada uma amostra. Então, destes 1.000µL, retirou-se 1µL e este foi semeado em placas de Petri contendo Agar-sangue e Levine para isolamento e identificação de bactérias Gram+ e Gram-, respectivamente. Essas placas foram incubadas em estufa bacteriológica a 37ºC, 48 horas, e as unidades formadoras de colônias que cresceram foram contadas e seus percentuais calculados. Para a bacterioscopia foram confeccionadas lâminas coradas pelo método de Gram. RESULTADOS: Do 5º ao 21º dia de vida os pesos corporais do grupo desnutrido (33,6g:42,8g, desvio-padrão=27,2g) foram menores (p<0,001) que os do grupo nutrido (52,5g:56,3g, desvio-padrão=24,0g). Dos 60 aos 120 dias de vida os pesos foram reduzidos no grupo desnutrido (248,2g:290,2g, desvio-padrão=220,2g), quando comparados aos do grupo nutrido (306,2g:319,4g, desvio-padrão=219,5g) teste Mann Whitney, p<0,05. A microbiota foi composta de menor número de bactérias no grupo nutrido (4,2x10(6) unidades formadoras de colônias, desvio-padrão=1,2x10(6) unidades formadoras de colônias de bactérias/mL), comparado ao grupo desnutrido (7,4x10(6) unidades formadoras de colônias, desvio-padrão=1,0x10(6) unidades formadoras de colônias de bactérias/mL) teste "t", (p=0,026). Das bactérias isoladas em culturas, observou-se um padrão bacteriano semelhante nos dois grupos, com 70% de bactérias gram-positivas e 30% de bactérias gram-negativas. CONCLUSÃO: A desnutrição neonatal foi efetiva em reduzir o peso corporal e aumentar o crescimento bacteriano. Embora o padrão bacteriano não tenha sido alterado, o aumento do crescimento bacteriano pode induzir a um desequilíbrio na microbiota oral desfavorecendo assim, o hospedeiro.

Microbiology and Principles of Antimicrobial Therapy for Head and Neck Infections

The principles of antimicrobial management for head and neck infections include establishing an accurate clinical and microbiologic diagnosis and treating the patient initially with an empiric antimicrobial regimen based on predicted likelihood of success and reduced potential for resistance. Subsequent adjustments may be required based on clinical response and available culture results. This article summarizes the aerobic and anaerobic microbiology of selected acute and chronic infections of the head and neck and the approaches to antimicrobial therapy.

Microbiology in toothbrush samples from children exposed to lead in southern Thailand

OBJECTIVE

The purpose of this study was to evaluate the prevalence and level of selected oral bacterial species in association with dental caries in low versus high blood lead (PbB) children.

MATERIAL AND METHODS

With an observational cross-sectional design, a sample of 292 children aged 6-11 years from two primary schools around a shipyard, known to be an area contaminated with lead, were examined. The number of decayed and filled surfaces on deciduous teeth (dfs) and the number of decayed, missing, and filled surfaces on permanent teeth (DMFS) were recorded. Microbiological plaque samples were taken from each child with a toothbrush. Enumeration of 17 bacterial species was carried out using the checkerboard DNA-DNA hybridization technique.

RESULTS

Overall means (SD) of dfs and DMFS were 13.2 (9.5) and 1.3 (2.3), respectively. Prevalence of excessive count (>or=10(6) cells/sample) was 100% for 4 known cariogenic bacteria and over 95% in another 2 species. With Bonferroni correction for type I error adjustment, there was no significant association between the count of each bacterial species and PbB and caries experience. The checkerboard method is sensitive in bacteria detection, but may not be suitable for differentiating caries risk in the endemic population.

Oral bacteria in plaque and invading buccal cells of young orthodontic patients

INTRODUCTION

In this longitudinal study, patients with fixed orthodontic appliances served as models to determine whether Actinobacillus actinomycetemcomitans, Tannerella forsythia, and total streptococci increased after treatment, and whether treatment affected bacterial invasion into the adjacent buccal epithelial cells (BEC).

METHODS

Supragingival plaque, subgingival plaque, and BEC were collected from 27 patients before and at least 4 weeks after placement of orthodontic fixed appliances. Total sample DNA was determined, and bacteria were assayed by quantitative polymerase chain reaction. The BEC were also examined by confocal microscopy after fluorescent in-situ hybridization to visually detect the presence of each species bacteria in BEC.

RESULTS

Total DNA in supragingival and subgingival plaque increased after appliance placement (P = .005). There was also a significant increase in supragingival streptococci (P = .0002). By confocal microscopy, a trend toward fewer buccal cells recovered was found after appliance placement, and there was a significant increase in the percentage of buccal cells containing A. actinomycetemcomitans (P = .0058).

CONCLUSIONS

Appliance placement appeared to increase buccal cell susceptibility to A. actinomycetemcomitans invasion. This might be due to physical trauma or to leaching of metals from the appliances.

The papilla amplification flap for the treatment of a localized periodontal defect associated with a palatal groove

BACKGROUND

Teeth with a palatal groove often present with severe localized periodontal attachment loss including pocket formation and alveolar bone loss. The aim of the present case report was to describe the regenerative surgical treatment of periodontal and bone lesions associated with the subgingival extension of a palatal groove affecting a maxillary lateral incisor.

METHODS

The left maxillary lateral incisor of a systemically healthy young subject presented with a palatal probing depth of 10 mm with no gingival recession at the buccal and palatal surfaces; the neighboring interdental papillae were intact. The radiograph showed a radiolucency area distal to the affected tooth. Treatment procedures consisted of: 1) the papilla amplification flap with the use of enamel matrix proteins as the regenerative periodontal material; 2) the elimination/flattening of the radicular portion of the palatal groove; and 3) the sealing of the coronal portion of the groove with composite flow.

RESULTS

The clinical examination at 1 year revealed a clinical attachment gain (8 mm) with a shallow residual probing depth (2 mm) and no increase in gingival recession. The radiographic examination showed the complete disappearance of the radiolucency area suggesting bone fill.

CONCLUSIONS

The present study indicated that localized periodontal defects associated with a palatal groove can be successfully treated by means of the papilla amplification flap with the use of enamel matrix protein as the regenerative material. The long-term stability of such successful results needs to be determined.

Oral pathogens and allergic disease: results from the Third National Health and Nutrition Examination Survey

BACKGROUND

The hygiene hypothesis contends that fewer opportunities for infection have led to increases in the prevalences of asthma and other allergic diseases.

OBJECTIVE

This study evaluated the association between asthma, wheeze, and hay fever and antibodies to 2 oral bacteria associated with periodontal disease.

METHODS

Data were obtained from the Third National Health and Nutrition Examination Survey. Serum levels of IgG antibodies to Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis were quantified by enzyme-linked immunoassays in 9385 subjects age 12 years and older. The outcomes were current asthma, wheeze, and hay fever. Odds ratios (ORs) representing a 1-log-unit increase in IgG concentrations were estimated with logistic regression. ORs were adjusted for 8 confounders and weighted to represent the US population.

RESULTS

For each disease outcome, geometric mean antibody concentrations were higher in persons without the disease outcome than with the disease outcome. For a 1-log-unit increase in P gingivalis antibody concentration, adjusted ORs were 0.41 (95% CI, 0.20-0.87) for asthma, 0.43 (0.23-0.78) for wheeze, and 0.45 (0.23-0.93) for hay fever. For A actinomycetemcomitans, those ORs were 0.56 (0.19-1.72), 0.39 (0.17-0.86), and 0.48 (0.23-1.03), respectively.

CONCLUSION

Consistent with the hygiene hypothesis, higher concentrations of IgG antibodies to P gingivalis were significantly associated with lower prevalences of asthma, wheeze, and hay fever, and higher concentrations of IgG antibodies to A actinomycetemcomitans were significantly associated with a lower prevalence of wheeze.

CLINICAL IMPLICATIONS

Colonization of the oral cavity by bacteria and other microbes might play a protective role in the etiology of allergic disease.

Distribution of 10 periodontal bacteria in saliva samples from Japanese children and their mothers

OBJECTIVE

We analyzed the distribution of 10 periodontal bacteria species (Porphyromonas gingivalis, Tannerella forsythensis, Prevotella intermedia, Prevotella nigrescens, Campylobacter rectus, Eikenella corrodens, Actinobacillus actinomycetemcomitans, Capnocytophaga ochracea, Capnocytophaga sputigena, and Treponema denticola) in children, and then compared their distribution in those children and their mothers, with special attention given to three of the species known as the red complex (P. gingivalis, T. forsythensis, and T. denticola) whose presence has been shown to be associated with conditions related to periodontal diseases.

METHODS

One hundred thirteen pairs of children and their mothers were randomly selected from patients treated at the Pedodontic Clinic of Osaka University Dental Hospital. Saliva samples were taken at the second visit prior to receiving professional tooth brushing instruction. Genomic DNA was extracted from each saliva sample, followed by a polymerase chain reaction assay with species-specific sets of primers.

RESULTS

A. actinomycetemcomitans was the most frequently detected species in the mothers, followed by C. sputigena, P. gingivalis, and T. forsythensis, while C. sputigena had the highest detection rate, followed by A. actinomycetemcomitans and T. denticola in the children. The detection rate of the red complex species in children whose mothers possessed the same species was significantly higher than in those whose mothers did not possess them.

CONCLUSIONS

Our results indicate a correlation between the presence of periodontal bacteria in children and their mothers, while the presence of red complex bacteria in children was highly associated with that in their mothers.

Langerhans' Cell Histiocytosis in a 5-Year-Old Girl: Evidence of Periodontal Pathogens

BACKGROUND

Langerhans' cell histiocytosis (LCH) is a rare disorder characterized by Langerhans' cell proliferation in various organs or tissues. When periodontal tissue is involved, clinical manifestations can vary from gingival recession and pocket formation to severe alveolar bone loss. This case report describes periodontal pathogens found in the pockets of involved primary teeth.

METHODS

A 5-year-old girl with LCH presented with loose teeth. Intraoral examination and radiographs revealed deep pockets and severe bone loss around all primary molars. Bacterial samples were obtained from saliva and subgingival plaque and analyzed for the presence of five periodontopathic bacteria using a polymerase chain reaction (PCR) method. Due to severe periodontal destruction, all primary molars were extracted, and a gingival biopsy was taken from tooth T to confirm the diagnosis of LCH.

RESULTS

The biopsy specimen revealed the histologic features of LCH. The patient was diagnosed as having periodontitis as a manifestation of LCH. PCR results of subgingival plaque from LCH-affected molars indicated the presence of Porphyromonas gingivalis, Tannerella forsythensis, Treponema denticola, and Prevotella intermedia. However, Actinobacillus actinomycetemcomitans was absent from these teeth. No tested bacteria were found in the non-affected anterior teeth.

CONCLUSIONS

The bacteria commonly associated with periodontal disease were detected in subgingival plaque samples from this LCH patient. More microbiological data are required to understand the role of these bacteria in LCH-associated periodontal destruction.

Distribution ofPorphyromonas gingivalis fimAGenotypes in Japanese Children and Adolescents

BACKGROUND

Porphyromonas gingivalis is considered to be one of the most important pathogens in periodontal disease and its fimA genes have been classified into six variants (types I through V and Ib). A majority of the P. gingivalis organisms isolated from periodontitis patients are type II, followed by type IV, while type I is prevalent in healthy adults.

METHODS

A total of 650 saliva samples were taken from 464 children (3 to 18 years of age), who visited Osaka University Dental Hospital. Genomic DNA was extracted from each sample and analyzed using a polymerase chain reaction (PCR) method with P. gingivalis-specific primers, followed by an additional PCR assay to determine the fimA genotypes for P. gingivalis- positive subjects.

RESULTS

Fifteen (3.23%) of the subjects were P. gingivalis-positive and none of those samples showed a positive reaction to the type II fimA-specific primers, while four, one, and two subjects were shown to be positive for the type I, Ib, and III genotypes, respectively. In addition, the type IV genotype was detected in three subjects in the older age group.

CONCLUSIONS

Our findings suggest that a limited number of children harbor P. gingivalis, and that the distribution of type II and IV fimA genotypes is extremely low. Further, some adolescents were found to possess the type IV fimA genotype which has been shown to be possibly related to adult periodontitis, in contrast to types I, III, and V.

Relationship of Actinobacillus actinomycetemcomitans serotypes to periodontal condition: prevalence and proportions in subgingival plaque

No study available has utilized the new classification scheme (the consensus report of the American Academy of Periodontology 1999) to determine the prevalence of Actinobacillus actinomycetemcomitans in different periodontal conditions. The purpose of this study was to investigate prevalence and proportions of A. actinomycetemcomitans serotypes in subgingival plaque samples from a young Taiwanese population with aggressive periodontitis, chronic periodontitis and no periodontal disease. A total of 221 subgingival plaque samples from 171 diseased subjects (70 had aggressive periodontitis, and 101 had chronic periodontitis) (mean age 25.0 +/- 8.2 yr) and 50 periodontally healthy subjects (mean age 18.4 +/- 9.5 yr) were screened for A. actinomycetemcomitans. Serotypes of A. actinomycetemcomitans were determined by an indirect immunofluorescence assay using serotype-specific polyclonal antisera to A. actinomycetemcomitans strains ATCC 29523 (serotype a), ATCC 43728 (serotype b) and ATCC 33384 (serotype c). Prevalence (% of positive samples) of A. actinomycetemcomitans was 84.3% in aggressive periodontitis, 60.4% in chronic periodontitis, and 64.0% in periodontally healthy subjects. Proportions of A. actinomycetemcomitans (mean percentage per total bacteria) in periodontally healthy subjects were significantly lower than in aggressive periodontitis subjects. The proportion of serotype b in subjects with aggressive periodontitis and subjects with chronic periodontitis were significantly greater than that in periodontally healthy subjects. The proportion of serotype c in periodontally healthy subjects was much higher than that in chronic periodontitis subjects. The results of this study suggest that prevalence and proportions of A. actinomycetemcomitans are significantly greater in patients with aggressive periodontitis than in those with chronic periodontitis. Serotype b is the predominant serotype of A. actinomycetemcomitans in patients with diseased periodontal conditions. Serotype c is a more common serotype detected in periodontally healthy subjects.

Increased Interleukin-18 in Patients With Juvenile Idiopathic Arthritis and Early Attachment Loss

BACKGROUND

Patients with juvenile idiopathic arthritis (JIA) have been shown to have incipient attachment loss (AL) more frequently than systemically healthy individuals. This study investigated neutrophil activity and proinflammatory cytokines in these patients and aged-matched controls.

METHODS

Elastase activity, measured with a low molecular weight substrate (S-2484), and interleukin-1beta (IL-1beta), measured with the enzyme-linked immunosorbent assay (ELISA), were analyzed in the gingival fluid of 38 patients with JIA and 29 controls. IL-1beta and interleukin-18 (IL-18) were measured with ELISA in the serum of the same groups. Subgingival plaque was analyzed by DNA probes to detect 12 bacteria.

RESULTS

Significantly elevated serum levels of IL-1beta and IL-18 were found in the JIA group. No differences were found in the gingival fluid levels of elastase and IL-1beta between groups, or in the frequency of subjects positive to most of the bacteria analyzed, except F. nucleatum, C. rectus, P. micros, and S. intermedius, which were significantly more frequent in the control group. When the JIA group was subdivided according to the presence/absence of AL, IL-18 was significantly increased in the JIA subgroup with AL compared to those without it. There were no differences in the subgingival microbiota between the subgroups.

CONCLUSION

The findings of increased serum IL-18 and IL-1beta in patients with JIA accompanied by a similar subgingival microbiota suggest that the increased frequency of incipient attachment loss observed in these patients might be due to their altered systemic inflammatory response, making them more susceptible to periodontal disease.