Prevalence of periodontal breakdown in adolescents and presence of Actinobacillus actinomycetemcomitans in subjects with attachment loss

The promise and challenges of genomics-informed periodontal disease diagnoses

Recent advances in human genomics and the advent of molecular medicine have catapulted our ability to characterize human and health and disease. Scientists and healthcare practitioners can now leverage information on genetic variation and gene expression at the tissue or even individual cell level, and an enormous potential exists to refine diagnostic categories, assess risk in unaffected individuals, and optimize disease management among those affected. This review investigates the progress made in the domains of molecular medicine and genomics as they relate to periodontology. The review summarizes the current evidence of association between genomics and periodontal diseases, including the current state of knowledge that approximately a third of the population variance of periodontitis may be attributable to genetic variation and the management of several monogenic forms of the disease can be augmented by knowledge of the underlying genetic cause. Finally, the paper discusses the potential utility of polygenic risk scores and genetic testing for periodontitis diagnosis now and in the future, in light of applications that currently exist in other areas of medicine and healthcare.

Aggregatibacter actinomycetemcomitans Leukotoxin Activates the NLRP3 Inflammasome and Cell-to-Cell Communication

Carriers of highly leukotoxic genotypes of Aggregatibacter actinomycetemcomitans are at high risk for rapid degradation of tooth-supporting tissues. The leukotoxin (LtxA) expressed by this bacterium induces a rapid pro-inflammatory response in leukocytes that results in cell death. The aim of the present study was to increase the understanding of LtxA-induced leukocyte activation mechanisms and of possible associated osteoclast differentiation. The effect of LtxA on activation of the inflammasome complex was studied in THP-1 wild type and in NLRP3- and ASC knockout cells. Cell-to-cell communication was assessed by fluorescent parachute assays, and THP-1 differentiation into osteoclast-like cells was investigated microscopically. The results showed that LtxA induced inflammatory cell death, which involved activation of the NLRP3 inflammasome and gap junction cell-to-cell communication. THP-1 cells treated with lipopolysaccharide (LPS) and LtxA together differentiated into an osteoclast-like phenotype. Here, LPS prevented LtxA-mediated cell death but failed to induce osteoclast differentiation on its own. However, pit formation was not significantly enhanced by LtxA. We conclude that A. actinomycetemcomitans leukotoxicity mediates activation of the NLRP3 inflammasome and cell-to-cell communication in the induced pro-inflammatory cell death. In addition, LtxA stimulated differentiation towards osteoclasts-like cells in LPS-treated THP-1 cells.

Diagnostic Accuracy of Oral Fluids Biomarker Profile to Determine the Current and Future Status of Periodontal and Peri-Implant Diseases

Severe periodontitis is ranked as the sixth most prevalent disease affecting humankind, with an estimated 740 million people affected worldwide. The diagnosis of periodontal diseases mainly relies upon assessment of conventional clinical parameters. However, these parameters reflect past, rather than current, clinical status or future disease progression and, likely, outcome of periodontal treatment. Specific and sensitive biomarkers for periodontal diseases have been examined widely to address these issues and some biomarkers have been translated as point-of-care (PoC) tests. The aim of this review was to provide an update on PoC tests for use in the diagnosis and management of periodontal diseases. Among the PoC tests developed so far, active matrix metalloproteinase-8 has shown promising results in terms of diagnostic and prognostic values. However, further studies are required to increase the sensitivity and specificity via combining more than one biomarker and merging these test kits with periodontal risk assessment tools. Furthermore, the validity of these test kits needs to be investigated by applying the results in further independent studies and the impact on these test kits', together with the results of risk factors for periodontal diseases, such as diabetes and smoking, also needs to be examined.

Simplified basic periodontal examination in adolescents before and after a tailored treatment dental program

BACKGROUND

The aim of this study was to evaluate the effectiveness of a tailored treatment dental program in adolescents in combination with a professional oral hygiene.

METHODS

Ninety-three adolescents (43 males and 50 females; mean age: 14±1.1 years) were included in this study and Plaque Index (PI) and simplified basic periodontal examination (BPE) were measured for each patient at T0 (screening) and at T1 (after 30 days). At T0 a professional dental hygiene treatment was performed and a tailored oral hygiene instruction protocol was adopted. All data were statistically analyzed using Student's t-test and the level of significance was set at P<0.05.

RESULTS

A statistically significant decrease of PI was found from T0 (2.3±0.6) to T1 (0.9±0.3) (P<0.05). Moreover, also a significant decrease (P<0.05) of BPE was observed after 30 days. Girls exhibited a higher significant BPE index improvement (0.47±0.2) in comparison to boys (0.3±0.1) at the end of the follow-up (P<0.05).

CONCLUSIONS

A tailored oral hygiene instruction protocol has resulted in a decreased plaque accumulation and gingival inflammation.

Global prevalence of aggressive periodontitis: A systematic review and meta-analysis

AIM

The prevalence of aggressive periodontitis (AgP) varies considerably between studies. The aim of this meta-analysis was to estimate, throughout the world, the prevalence of this disease.

MATERIALS AND METHODS

Pubmed/Medline, Scopus, Science Direct, EBSCO and Cochrane library were systematically searched up to March 2018. Study selection criteria included cross-sectional studies reporting prevalence of AgP in non-specific population and permanent dentition. We assessed risk of bias using the Joanna Briggs Institute tool. A random effect meta-analysis model was used to estimate the prevalence of AgP. Publication bias was assessed by Begg and Egger's tests and visual aspect of funnel plot.

RESULTS

A total of 33 articles were included. Pooled prevalence for AgP was 1.6% (95% CI 1.1-2.3). Higher pooled prevalence rates were reported in Africa (4.2%, 95% CI 2.0-7.1) and South America (4.0%, 95% CI 0.9-9.1) compared with Europe (0.1%, 95% CI 0.1-0.2). A pooled prevalence of 1.2%, 95% CI 0.5-2.2 was found in Asia and 0.8%, 95% CI 0.4-1.4 in North America. Heterogeneity between groups was statistically significant (Q statistic p < .001).

CONCLUSIONS

A relatively high prevalence of AgP was found in Africa. However, the data support the weakness of the definition of this form of periodontal disease. Studies with less heterogeneity are needed to address accurately the prevalence of AgP.

Familial tendency as a determinant of tooth loss during long-term periodontal therapy

AIM

Little evidence exists on how familial tendencies affect the long-term success of periodontal therapy. The aim of this study was to compare outcomes for two generations and their control patients treated in the same private practice.

MATERIALS/METHODS

Parents and their children were observed for tooth loss between 1986 and 2017. Matching control groups were identified from the same practice, one for the parent and one for the children group. The control patients had no close family members with a history of periodontal diseases. Both the generations and control groups completed a similar course of periodontal therapy. The matching strategy aimed at making the groups as similar as possible with respect to well-known risk and prognostic factors. The data were analysed by multiple regression where the outcome was the number of teeth lost due to periodontal disease.

RESULTS

A total of 435 patients were identified (148 parents, 154 children and 133 controls). 72 parents and 61 children (133) had more than 5 years follow-up (average 15.5 and 12.9 years, respectively). Balancing tests showed that the matching was successful. 65% of tooth loss was attributable to close family history. The regression showed that the parent generation lost 1.02 more teeth than the controls, while the children lost 0.61 more teeth.

CONCLUSION

Having close family members with a history of periodontal diseases is a strong prognostic factor affecting the long-term outcome of periodontal therapy.

Pathogenicity of the highly leukotoxic JP2 clone of Aggregatibacter actinomycetemcomitans and its geographic dissemination and role in aggressive periodontitis

For decades, Aggregatibacter actinomycetemcomitans has been associated with aggressive forms of periodontitis in adolescents. In the middle of the 1990s, a specific JP2 clone of A. actinomycetemcomitans, belonging to the cluster of serotype b strains of A. actinomycetemcomitans and having a number of other characteristics, was found to be strongly associated with aggressive forms of periodontitis, particularly in North Africa. Although several longitudinal studies still point to the bacterial species, A. actinomycetemcomitans as a risk factor of aggressive periodontitis, it is now also widely accepted that the highly leukotoxic JP2 clone of A. actinomycetemcomitans is implicated in rapidly progressing forms of aggressive periodontitis. The JP2 clone strains are highly prevalent in human populations living in Northern and Western parts of Africa. These strains are also prevalent in geographically widespread populations that have originated from the Northwest Africa. Only sporadic signs of a dissemination of the JP2 clone strains to non-African populations have been found despite Africans living geographically widespread for hundreds of years. It remains an unanswered question if a particular host tropism exists as a possible explanation for the frequent colonization of the Northwest African population with the JP2 clone. Two exotoxins of A. actinomycetemcomitans are known, leukotoxin (LtxA) and cytolethal distending toxin (Cdt). LtxA is able to kill human immune cells, and Cdt can block cell cycle progression in eukaryotic cells and thus induce cell cycle arrest. Whereas the leukotoxin production is enhanced in JP2 clone strains thus increasing the virulence potential of A. actinomycetemcomitans, it has not been possible so far to demonstrate such a role for Cdt. Lines of evidence have led to the understanding of the highly leukotoxic JP2 clone of A. actinomycetemcomitans as an aetiological factor of aggressive periodontitis. Patients, who are colonized with the JP2 clone, are likely to share this clone with several family members because the clone is transmitted through close contacts. This is a challenge to the clinicians. The patients need intense monitoring of their periodontal status as the risk for developing severely progressing periodontal lesions are relatively high. Furthermore, timely periodontal treatment, in some cases including periodontal surgery supplemented by the use of antibiotics, is warranted. Preferably, periodontal attachment loss should be prevented by early detection of the JP2 clone of A. actinomycetemcomitans by microbial diagnostic testing and/or by preventive means.

Risk factors for periodontal disease

Risk factors play an important role in an individual's response to periodontal infection. Identification of these risk factors helps to target patients for prevention and treatment, with modification of risk factors critical to the control of periodontal disease. Shifts in our understanding of periodontal disease prevalence, and advances in scientific methodology and statistical analysis in the last few decades, have allowed identification of several major systemic risk factors for periodontal disease. The first change in our thinking was the understanding that periodontal disease is not universal, but that severe forms are found only in a portion of the adult population who show abnormal susceptibility. Analysis of risk factors and the ability to statistically adjust and stratify populations to eliminate the effects of confounding factors have allowed identification of independent risk factors. These independent but modifiable, risk factors for periodontal disease include lifestyle factors, such as smoking and alcohol consumption. They also include diseases and unhealthy conditions such as diabetes mellitus, obesity, metabolic syndrome, osteoporosis, and low dietary calcium and vitamin D. These risk factors are modifiable and their management is a major component of the contemporary care of many periodontal patients. Genetic factors also play a role in periodontal disease and allow one to target individuals for prevention and early detection. The role of genetic factors in aggressive periodontitis is clear. However, although genetic factors (i.e., specific genes) are strongly suspected to have an association with chronic adult periodontitis, there is as yet no clear evidence for this in the general population. It is important to pursue efforts to identify genetic factors associated with chronic periodontitis because such factors have potential in identifying patients who have a high susceptibility for development of this disease. Many of the systemic risk factors for periodontal disease, such as smoking, diabetes and obesity, and osteoporosis in postmenopausal women, are relatively common and can be expected to affect most patients with periodontal disease seen in clinics and dental practices. Hence, risk factor identification and management has become a key component of care for periodontal patients.

Progression of attachment loss is strongly associated with presence of the JP2 genotype of Aggregatibacter actinomycetemcomitans: a prospective cohort study of a young adolescent population

AIM

To assess the progression of attachment loss (AL) during a 2-year period according to the presence of JP2 and non-JP2 genotypes of Aggregatibacter actinomycetemcomitans in a Ghanaian adolescent population.

METHODS

A total of 500 adolescents (mean age 13.2 years, SD ± 1.5) were enrolled in the study. After 2 years, 397 (79.4%) returned for a periodontal re-examination, including the measurement of AL. The carrier status of the JP2 and non-JP2 genotypes of A. actinomycetemcomitans was evaluated in a baseline examination 2 years earlier.

RESULTS

Individuals who carried the JP2 genotype of A. actinomycetemcomitans had a significantly increased risk [relative risk (RR) = 7.3] of developing AL ≥ 3 mm. The mean AL at the follow-up and the mean 2-year progression of AL were significantly higher in the JP2 genotype-positive group (n = 38) compared with the group positive for the non-JP2 genotypes of A. actinomycetemcomitans (n = 169), and the group of A. actinomycetemcomitans-negative individuals (n = 190). The JP2 genotype was strongly associated with the progression of AL ≥ 3 mm (OR = 14.3). The non-JP2 genotypes of A. actinomycetemcomitans were also, however, less pronounced, associated with the progression of AL ≥ 3 mm (OR = 3.4).

CONCLUSION

The JP2 genotype of A. actinomycetemcomitans is strongly associated with the progression of AL.

Utility of Periodontal exploration in patients with Fibromyalgia

Objetive: Fibromyalgia (FM) is a chronic pain syndrome with unknown etiology, which affects predominantly women. Mitochondrial alteration could have a role in the pathophysilogical mechanisms of inflammatory conditions as FM and periodontitis. The aim of the present study was assay the relationship between both diseases and mitochondrial dysfunction. Patient and Methods: We study the presence of periodontitis in twelve patients diagnosed of FM and mitochondrial dysfunction described. The diagnosis of FM was established according to ACR criteria and clinical symptoms were evaluated using the Fibromyalgia Impact Questionnaire (FIQ) and Beck Depression Inventory (BDI). Results: Only one patients of twelve included and agreed to participate in the study were diagnosed with periodontitis. Conclusions: Pending studies with larger numbers of patients, we can conclude that mitochondrial dysfunction in FM is a itself event not related with periodontitis. Periodontitis could be considered a exclusion criterion in all studies about mitochondrial dysfunction in patients.

Key words:Peridontitis, fibromyalgia, mitocondrial dysfunction, oxidative stress.

The association between self-reported tooth loss and cognitive function in the REasons for Geographic And Racial Differences in Stroke study: an assessment of potential pathways

BACKGROUND

Several mechanisms may associate tooth loss and related oral inflammation with cognitive impairment. The authors studied the relationship between tooth loss and cognitive function.

METHODS

The REasons for Geographic And Racial Differences in Stroke study is a national longitudinal study of more than 30,000 African American and white adults 45 years or older. Data for tooth loss, cognitive function and potential confounding variables were available for 9,853 participants at the time of analysis. The authors used incremental linear regression modeling to investigate the cross-sectional association between self-reported tooth loss and cognitive function.

RESULTS

In unadjusted analysis (mean learning followed by recall; α level of significance of .05), the loss of six to 16 teeth and the loss of more than 16 teeth were associated with poorer cognitive function compared with the loss of no teeth. Attenuated associations persisted after the authors adjusted for demographic and systemic risk factors. The full model, which was adjusted for socioeconomic status (SES), revealed no association between tooth loss and cognitive function.

CONCLUSION

Tooth loss may be associated with cognitive function; however, this association is mediated by age and SES.

CLINICAL IMPLICATIONS

Tooth loss due to periodontal disease may be a marker for low SES, and the interplay of these factors with advanced age may confer risk of having poorer cognitive function. Further studies are needed to clarify these associations.

The genetic impact of the Q551R interleukin-4 receptor alpha polymorphism for aggressive or chronic periodontitis and the occurrence of periodontopathic bacteria

OBJECTIVE

The Q551R polymorphism of the gene encoded for the α chain of the interleukin-4 receptor (IL-4RA) could influence both IL-4 and IL-13 signalling. Since both cytokines could be important in the pathogenesis of periodontitis the aim of this study was to evaluate putative associations of the Q551R polymorphism to generalized aggressive or chronic periodontitis and five periodontopathogens.

DESIGN

154 patients with severe generalized periodontitis (chronic: n=68, mean age=48.7 ± 9.4 years; aggressive: n=86, mean age=40.4 ± 9.8 years) and controls without periodontitis (n=89, mean age=46.2 ± 10.8 years) were included. The Q551R polymorphism was analysed by PCR-SSP CTS-Kit, Heidelberg, Germany. Subgingival bacteria were determined molecular biologically using micro-Ident test (HainLifescience, Nehren, Germany). Distributions of single alleles and genotypes were calculated by Chi(2)-test with Yates correction or Fisher's exact test. Adjusted odds ratios were generated by logistic regression with respect to established cofactors for periodontitis.

RESULTS

The mutant allele R551 (p(Y)=0.013) and the genotypes QR+RR (p(B)=0.024) occurred more frequently amongst patients with chronic periodontitis vs. controls. Carriers of the Q551R polymorphism had an increased adjusted odds ratio for chronic periodontitis (OR=3.2, 95%CI 1.5-6.5, p=0.002) and severe periodontitis (chronic+aggressive) in general (OR=2.0, 95%CI 1.1-3.6, p=0.003). Moreover, in the total study cohort the Q551R polymorphism was associated with the presence of Tannerella forsythia (90.3% vs. 78.0%, p(Y)=0.01).

CONCLUSIONS

The Q551R IL-4RA polymorphism is a putative risk indicator for severe chronic periodontitis, but was not significant associated to AP.

Presence of Aggregatibacter actinomycetemcomitans in young individuals: a 16-year clinical and microbiological follow-up study

AIM

To look for clinical signs of periodontal disease in young adults who exhibited radiographic bone loss and detectable numbers of Aggregatibacter actinomycetemcomitans in their primary dentition.

MATERIAL AND METHODS

Periodontal status and radiographic bone loss were examined in each of the subjects 16 years after the baseline observations. Techniques for anaerobic and selective culture, and checkerboard, were used to detect periodontitis-associated bacterial species. The isolated A. actinomycetemcomitans strains were characterized by polymerase chain reaction.

RESULTS

Signs of localized attachment loss were found in three out of the 13 examined subjects. A. actinomycetemcomitans was recovered from six of these subjects and two of these samples were from sites with deepened probing depths and attachment loss. Among the isolated A. actinomycetemcomitans strains, serotypes a-c and e, but not d or f, were found. None of the isolated strains belonged to the highly leucotoxic JP2 clone, and one strain lacked genes for the cytolethal distending toxin.

CONCLUSIONS

This study indicates that the presence of A. actinomycetemcomitans and early bone loss in the primary dentition does not necessarily predispose the individual to periodontal attachment loss in the permanent dentition.

Detection of herpesviruses and periodontal pathogens in subgingival plaque of patients with chronic periodontitis, generalized aggressive periodontitis, or gingivitis

BACKGROUND

Herpesviruses may be related to the etiology of aggressive periodontitis (AgP) and chronic periodontitis (CP) by triggering periodontal destruction or by increasing the risk for bacterial infection. This case-control study evaluated the presence of herpes simplex virus type I (HSV-1), Epstein-Barr virus type I (EBV-1), human cytomegalovirus (HCMV), Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans), Porphyromonas gingivalis, Prevotella intermedia, and Tannerella forsythia (previously T. forsythensis) in patients with generalized AgP (AgP group), CP (CP group), or gingivitis (G group) and in healthy individuals (C group).

METHODS

Subgingival plaque samples were collected with paper points from 30 patients in each group. The nested polymerase chain reaction (PCR) method was used to detect HSV-1, EBV-1, and HCMV. Bacteria were identified by 16S rRNA-based PCR.

RESULTS

HSV-1, HCMV, and EBV-1 were detected in 86.7%, 46.7%, and 33.3% of the AgP group, respectively; in 40.0%, 50.0%, and 46.7% of the CP group, respectively; in 53.3%, 40.0%, and 20.0% of the G group, respectively; and in 20.0%, 56.7%, and 0.0% of the C group, respectively. A. actinomycetemcomitans was detected significantly more often in the AgP group compared to the other groups (P <0.005). P. gingivalis and T. forsythia were identified more frequently in AgP and CP groups, and AgP, CP, and G groups had higher frequencies of P. intermedia compared to the C group.

CONCLUSION

In Brazilian patients, HSV-1 and EBV-1, rather than HCMV, were more frequently associated with CP and AgP.

Prevalence and distribution of principal periodontal pathogens worldwide

BACKGROUND

Detailed genetic analysis of bacteria has demonstrated an unanticipated genetic diversity within species, which often reveals evolutionary lineages that are disproportionately associated with infection. There is evidence that some evolutionary lineages of bacteria have adapted to particular ethnic groups.

AIM

This review analyzes to what extent observed differences in periodontal disease prevalence among ethnically or geographically distinct populations may be explained by restricted host adaptation of clones of principal periodontal pathogens.

RESULTS

Carriage rates of several putative periodontal pathogens and particular subsets of these species vary between ethnic groups. Few of these differences can, with the limited information available, be directly related to differences in periodontal disease prevalence. Asian populations are regularly colonized with Actinobacillus actinomycetemcomitans serotype c with questionable pathogenic potential. Conversely, the JP2 clone of A. actinomycetemcomitans has enhanced virulence and causes significantly higher prevalence of aggressive periodontitis in adolescents whose descent can be traced back to the Mediterranean and Western parts of Africa. Some genetically distinct types of Porphyromonas gingivalis are more associated with disease than others, but additional work is required to relate this to clinical differences.

CONCLUSIONS

Studies that take into account differences linked to the genetics of both patients and potential pathogens are likely to give better insight into the aetiology of periodontal diseases.

Expression of FcgammaRs and mCD14 on polymorphonuclear neutrophils and monocytes may determine periodontal infection

Variance in expression of receptors for immunoglobulin G (FcgammaRs), complement (CR3) and lipopolysaccharide (mCD14) on polymorphonuclear neutrophils (PMNs) and monocytes might affect susceptibility for infection with certain pathogens in periodontitis, a chronic infectious disease of tooth-supportive tissues. Levels of FcgammaRI, IIa, III, CR3 and mCD14 on PMNs and monocytes were measured in 19 periodontitis patients and 18 healthy controls. Subgingival infection with Aggregatibacter actinomycetemcomitans (Aa) and Porphyromonas gingivalis (Pg) was determined. Activation of PMNs and monocytes in response to stimulation with Aa and Pg was assessed by means of change in mCD14 expression. Periodontitis is associated with an enrichment of the FcgammaRIII(+) monocytes (P = 0.015) with concomitant low mCD14 (P = 0.001). Unadjusted data showed that the subjects culture-positive for Aa (Aa(+)) had significantly lower expression of monocytic FcgammaRI (P = 0.005) and FcgammaRIIa (P = 0.015) than Pg(+) subjects. The FcgammaRI was still lower on monocytes from Aa(+) subjects after adjusting for the background factors (P = 0.037). PMNs from Aa(+) subjects responded in a hyper-reactive manner, in particular when stimulated with Aa (P = 0.011). Lower FcgammaRs expression by monocytes is related to a higher susceptibility of a subject to become infected with Aa. The higher proportion of FcgammaRIII(+) monocytes may be involved in the chronicity of this condition. Hyper-reactive PMNs in Aa(+) subjects may contribute to accelerated breakdown of tooth-supportive tissues.

Case definitions for use in population-based surveillance of periodontitis

Many definitions of periodontitis have been used in the literature for population-based studies, but there is no accepted standard. In early epidemiologic studies, the two major periodontal diseases, gingivitis and periodontitis, were combined and considered to be a continuum. National United States surveys were conducted in 1960 to 1962, 1971 to 1974, 1981, 1985 to 1986, 1988 to 1994, and 1999 to 2000. The case definitions and protocols used in the six national surveys reflect a continuing evolution and improvement over time. Generally, the clinical diagnosis of periodontitis is based on measures of probing depth (PD), clinical attachment level (CAL), the radiographic pattern and extent of alveolar bone loss, gingival inflammation measured as bleeding on probing, or a combination of these measures. Several other patient characteristics are considered, and several factors, such as age, can affect measurements of PD and CAL. Accuracy and reproducibility of measurements of PD and CAL are important because case definitions for periodontitis are based largely on either or both measurements, and relatively small changes in these values can result in large changes in disease prevalence. The classification currently accepted by the American Academy of Periodontology (AAP) was devised by the 1999 International Workshop for a Classification of Periodontal Diseases and Conditions. However, in 2003 the Centers for Disease Control and Prevention and the AAP appointed a working group to develop further standardized clinical case definitions for population-based studies of periodontitis. This classification defines severe periodontitis and moderate periodontitis in terms of PD and CAL to enhance case definitions and further demonstrates the importance of thresholds of PD and CAL and the number of affected sites when determining prevalence.

Aggressive periodontitis in a 16-year-old Ghanaian adolescent, the original source of Actinobacillus actinomycetemcomitans strain HK1651 - a 10-year follow up

The highly leukotoxic JP2 clone of Actinobacillus actinomycetemcomitans is strongly associated with periodontitis in adolescents. Availability of the DNA sequence of the complete genome of A. actinomycetemcomitans strain HK1651, a representative strain of the JP2 clone (http://www.genome.ou.edu/act.html), has provided new possibilities in basic research regarding the understanding of the pathogenesis of A. actinomycetemcomitans in periodontitis. This case report describes the periodontal treatment of the original source of A. actinomycetemcomitans HK1651, a 16-year-old Ghanaian adolescent girl with aggressive periodontitis. The bacterial examination involved polymerase chain reaction analysis for presence of JP2 and non-JP2 types of A. actinomycetemcomitans. The treatment, including periodontal surgery supplemented by antibiotics, arrested the progression of periodontitis for more than 10 years. Initially, infection by A. actinomycetemcomitans, including the JP2 clone, was detected at various locations in the oral cavity and was not limited to the periodontal pockets. Post-therapy, the JP2 clone of A. actinomycetemcomitans disappeared, while the non-JP2 types of A. actinomycetemcomitans remained a part of the oral microflora.

Identification of genetic risk factors for periodontitis and possible mechanisms of action

AIM

To review the literature for genetic risk factors associated with periodontitis.

METHODS

Computerized search of the literature in English using key words: Periodontitis; Genes; Mutation; Polymorphism; Risk.

RESULTS AND CONCLUSIONS

Mutations in the cathepsin C gene (CTSC) have been identified as causal for the Papillon-Lefèvre syndrome (PLS), which includes prepubertal periodontitis (PP). Some CTSC mutations are causal for PP without PLS. No relationship has been demonstrated between CTSC mutations and other forms of periodontitis. Genetic polymorphisms in a candidate gene approach have been explored as risk factors for periodontitis. There is limited evidence that some polymorphisms in the genes encoding interleukins (IL)-1, Fc gamma receptors (Fc gammaR), IL-10 and the vitamin D receptor, may be associated with periodontitis in certain ethnic groups. However relatively large variations in carriage rates of the Rare (R)-alleles among studies on any polymorphism were observed. The available studies appear under-powered and do not adequately take into account other pertinent risk factors for periodontitis. Future studies should include larger cohorts, should clearly define phenotypes and should adequately control for other risk factors. In addition to the candidate gene approach, alternative strategies need to be considered to elucidate the gene variations, which confer risk for periodontitis.

Characteristics of Periodontal Microflora in Acute Myocardial Infarction

BACKGROUND

Periodontitis has been linked to increased risk of cardiovascular diseases. Systemic reactions associated with cardiovascular events may depend on characteristics of the subgingival microflora in periodontitis. Our objectives were to compare the numbers of cultivable bacteria, composition of subgingival microflora and clonal distribution of Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans) in two groups of patients with generalized chronic periodontitis (GCP), one with an acute myocardial infarction (AMI-GCP) and the other one without AMI (non-AMI-GCP).

METHODS

In all, 150 dentate individuals were screened for suitability to this study. Subgingival bacterial samples were collected from 11 AMI-GCP and 11 non-AMI-GCP patients who had been selected using strict inclusion criteria in an attempt to exclude confounding factors and to increase comparability of periodontal conditions by matching for periodontal probing depths and attachment levels. Culture methods were used to determine the total viable counts and occurrence and proportions of six periodontal bacterial species and yeasts. Polymerase chain reaction (PCR) technique was used to detect A. actinomycetemcomitans and Porphyromonas gingivalis (P. gingivalis). Intraspecies characterization of A. actinomycetemcomitans included serotyping and genotyping.

RESULTS

The mean proportions of P. gingivalis (P = 0.05) and Tannerella forsythensis (T. forsythensis) (P = 0.01) were significantly lower, but the numbers of Micromonas micros (M. micros) and A. actinomycetemcomitans were up to nine times higher and the mean total number of cultivable bacteria per sample higher (P <0.01) in AMI-GCP than in non-AMI-GCP.

CONCLUSION

The findings that no target subgingival species were overrepresented but the total bacterial number was higher in AMI-GCP than non-AMI-GCP patients may provide support to the hypothesis that elevated numbers of bacteria in close vicinity to sterile parenteral area present a risk for systemic health.

Aggressive Periodontitis in an Urban Population in Southern Brazil

BACKGROUND

There are limited data about the epidemiology and risk factors for aggressive periodontitis (AgP) in Latin American and Brazilian populations. The aim of this study was to assess the prevalence of AgP and the risk associated with demographic variables, smoking behavior, and other periodontal variables in a young urban population in southern Brazil.

METHODS

A representative sample of 612 subjects aged 14 to 29 years were sampled using a multistage probability method. A full-mouth clinical examination of six sites per tooth and an interview were performed in a mobile examination center. Subjects in the age groups 14 to 19 years and 20 to 29 years were classified with AgP if they had four or more teeth with attachment loss > or =4 mm or > or =5 mm, respectively.

RESULTS

AgP was found in 5.5% of the subjects. The disease occurred equally among males and females, but was twice as prevalent among non-whites than whites. In the age groups 20 to 24 years and 25 to 29 years, the AgP subjects had a significantly higher prevalence of tooth loss (90.2% versus 40.4% and 86.1% versus 43.4%, P <0.01) and mean number of missing teeth (2.6 versus 0.9 and 3.4 versus 1.5, P <0.05) than subjects without attachment loss. The AgP subjects also had significantly higher percentages of sites with dental plaque (P <0.0001), gingival bleeding (P <0.05), and supragingival calculus (P <0.0001) than normal subjects. The risk for AgP was higher in the 25- to 29-year than the 14- to 19-year age groups (odds ratio [OR] = 6.2), in the low than middle or high socioeconomic status (OR = 4.5), in moderate or heavy smokers than nonsmokers (OR = 3.1), and in subjects with > or =10% versus <10% sites with supragingival calculus (OR = 3.6).

CONCLUSION

Socioeconomic status, smoking, and dental calculus were significant risk indicators of aggressive periodontitis in this population. Suitable periodontal prevention programs implementing these risk indicators may prevent or reduce the prevalence of aggressive periodontitis in this and similar populations.

Microbiological profile of early onset/aggressive periodontitis patients

OBJECTIVES

The objectives of this study were to characterize the bacterial profile and to seek possible bacterial associations in the subgingival microbiota of early onset periodontitis/aggressive periodontitis patients by using two different techniques, culture and immunofluorescence.

MATERIAL AND METHODS

The study group consisted of 66 systemically healthy individuals with evidence of early onset periodontitis - 41 females and 25 males aged 23-35 years (mean 31.1 +/- 3.1 years). Bacterial samples were collected from the deepest site in each quadrant, resulting in a total of 264 sites with a mean probing pocket depth of 6.6 +/- 1.5 mm. Samples were cultured anaerobically and in 10% CO(2) using selective and nonselective media, and isolates were characterized to species level. Indirect immunofluorescence using monoclonal antibodies was applied to detect Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia (Bacteroides forsythus, Tannerella forsythensis), Prevotella intermedia/Prevotella nigrescens, Campylobacter rectus, Peptostreptococcus micros and Actinomyces israelii.

RESULTS

93.6% of sampled sites showed bleeding on probing and 23.5% were positive for suppuration. P. intermedia/P. nigrescens, P. gingivalis, and C. rectus were detected in 77.3-85.9% of samples using culture methods and in 85.6-91.3% using immunofluorescence. P. micros and A. actinomycetemcomitans were found, respectively, in 63.3% and 25.0% of all sites using culturing and in 58.7% and 27.7% sites using immunofluorescence. Significantly strong positive associations were observed between T. forsythia and C. rectus (odds ratio 109.46), and T. forsythia and P. gingivalis (odd ratio 90.26), whereas a negative association was seen between P. intermedia/P. nigrescens and A. actinomycetemcomitans (odds ratio 0.42). Coinfection by P. gingivalis, T. forsythia, P. intermedia/P. nigrescens and C. rectus was observed in 62.1% of the test sites, and in 89.4% of the studied subjects. The sensitivity of immunofluorescence for T. forsythia, C. rectus, P. intermedia/P. nigrescens and P. gingivalis was found to be very high (0.99-0.94) using culture as the reference detection method. The agreement between culture and immunofluorescence in detecting the presence or absence of the investigated species was 85.2-88.1% for P. gingivalis, P. intermedia/P. nigrescens, C. rectus, and T. forsythia, 75.9% for A. actinomycetemcomitans and 70.4% for P. micros.

CONCLUSIONS

The microbial profile of the early onset/aggressive periodontitis population was complex. The agreement between the two detection methods was very high.

Clinical course of chronic periodontitis

AIM

The purpose of this study was to assess the initiation and progression of periodontal disease during adult life.

MATERIALS AND METHODS

In a 26-year longitudinal investigation of the initiation and progression of chronic periodontitis that started in 1969 and included 565 men of Norwegian middle class, 223 who had participated in some, but not all, intermediate examinations presented at the last survey in 1995. Fifty-four individuals were available for examination in all seven surveys.

RESULTS

Covering the age range from 16 to 60 years, the study showed that at 16 years of age, 5% of the participants had initial loss of periodontal attachment (ILA > or = 2 mm) at one or more sites. Both the subject incidence and the site incidence increased with time, and by 32 years of age, all individuals had one or more sites with loss of attachment. As age progressed, new lesions affected sites, so that as these men approached 60 years of age approximately 50% of all available sites had ILA. An assessment of the intraoral distribution of the first periodontal lesion showed that, regardless of age, molars and bicuspids were most often affected. At and before the age of 40 years, the majority of ILA was found in buccal surfaces in the form of gingival recession. By 50 years, however, a greater proportion of sites presented with attachment loss attributed to pocket formation or a combination of pocket formation and gingival recession. As individuals neared 60 years of age, approximately half of the interproximal areas in posterior teeth had these lesions.

CONCLUSION

This investigation has shown that, in a well-maintained population who practises oral home care and has regular check-ups, the incidence of incipient periodontal destruction increases with age, the highest rate occurs between 50 and 60 years, and gingival recession is the predominant lesion before 40 years, while periodontal pocketing is the principal mode of destruction between 50 and 60 years of age.

Periodontal conditions in patients with juvenile idiopathic arthritis

OBJECTIVE

Our aim was to compare the periodontal conditions in a group of juvenile idiopathic arthritis (JIA) patients with those in a control group of healthy subjects (CTR).

MATERIAL AND METHODS

Thirty-two patients with JIA and 24 controls were selected. The measurements used to diagnose periodontal disease included plaque and bleeding scores, probing depths (PDs) and clinical attachment loss (CAL). Laboratory indicators of JIA activity included the erythrocyte sedimentation rate (ESR) and capsule-reactive protein (CRP). The Mann-Whitney test was used to evaluate the data (alpha = 0.05).

RESULTS

The mean ages were 15.9 (+/- 2.7) years and 14.7 (+/- 2.3) years for groups JIA and CTR, respectively. The median ESR was 42 mm/h 13 mm/h in the CTR group (p = 0.032) and the median CRP was 1.9 and 0.4 mg/l, respectively (p = 0.001). The prevalence of patients with a proximal attachment loss of 2mm or more in the JIA group was 25% and in controls it was 4.2%. The mean percentages of visible plaque and marginal bleeding were similar in the JIA (54 +/- 22 and 30 +/- 16, respectively) and CTR groups (44 +/- 18 and 29 +/- 11, respectively). The mean percentages of sites with PD > or = 4 mm were significantly higher in the JIA group (3 +/- 4.7) than in the CTR group (0.4 +/- 1.7) (p = 0.012). The mean percentages of sites with proximal CAL > or = 2 mm were 0.7 (+/- 1.4) in the JIA group and 0.001 (+/- 0.2) in the CTR group (p = 0.022).

CONCLUSION

Adolescents with JIA present more periodontal attachment loss than healthy controls, in spite of similar plaque and marginal bleeding levels.

Herpesviral-bacterial interactions in aggressive periodontitis

BACKGROUND

Human cytomegalovirus, Epstein-Barr virus and herpesvirus co-infections occur with significantly higher frequency in actively progressing than in stable periodontitis sites of adolescents and young adults. Also, periodontal presence of cytomegalovirus and Epstein-Barr virus is associated with increased occurrence of subgingival Porphyromonas gingivalis, Bacteroides forsythus, Dialister pneumosintes, Prevotella intermedia, Prevotella nigrescens, Treponema denticola and Actinobacillus actinomycetemcomitans.

AIM

This article reviews the evidence linking herpesviruses to the development of aggressive periodontitis and suggests a potential mechanism for herpesviral acceleration of the periodontal disease process.

CONCLUSIONS

It seems to be a reasonable supposition that the etiopathogenesis of various types of aggressive periodontitis includes the combined action of herpesviruses and specific bacterial species. New vaccines and vaccination technologies that are being developed against herpesviruses warrant testing for their ability to induce a protective immune response against destructive periodontal disease. Clearly, the importance of combined herpesviral-bacterial infections and associated host responses in the development of periodontitis needs to be studied further.

[Prevalence of aggressive periodontitis in adolescents and young adults from Vale do Paraíba]

The aim of the present study was to determine the prevalence of localized and generalized aggressive periodontitis, as well as of incidental attachment loss, in a population of adolescents and young adults aging between 15 and 25 years (19.4 +/- 3.44) from Vale do Paraíba - SP, who searched for general dental care at the Department of Dentistry, University of Taubaté, São Paulo. Six hundred patients, 244 male and 356 female subjects, were included in the studied sample. The periodontal status of this population was evaluated by measuring the depth of periodontal pockets, as well as attachment loss. The data were confirmed by means of radiographic examination. Measurements were performed in six sites per tooth. Ten subjects (1.66%) were diagnosed as having localized aggressive periodontitis, 2 males (aging 18.5 +/- 2.12 years) and 8 females (aging 19.2 +/- 3.91 years); 22 (3.66%) presented with generalized aggressive periodontitis, 6 males (aging 19.1 +/- 3.06 years) and 16 females (aging 20.1 +/- 2.71 years); and 86 individuals (14.3%) presented with incipient periodontitis, 29 males (aging 20.2 +/- 2.87 years) and 57 females (aging 21.1 +/- 2.79 years). There was a positive correlation between the female gender and the occurrence of periodontal disease.

Epidemiology of clinical attachment loss in adolescents

BACKGROUND

Relatively little is known about the prevalence, severity, and determinants of clinical attachment loss among adolescents.

METHODS

A multi-stage random sampling procedure was used to obtain a sample of 9,203 high school students aged 12 to 21 years from the Province of Santiago, Chile. All but 41 students were examined for clinical attachment loss in 6 sites of first and second molars and incisors. The students were interviewed with respect to tooth brushing habits, smoking habits, dental visits, and diabetic status. Logistic regression analyses were used to assess the relative strength of the associations between age, gender, smoking, tooth brushing habits, dental attendance patterns, diabetic status, and governmental school support and the occurrence of clinical attachment loss.

RESULTS

Overall, clinical attachment loss > or = 1 mm was seen in 69.2% of the students; > or = 2 mm in 16% of the students; and > or = 3 mm in 4.5%. The distribution of clinical attachment loss was markedly skewed, but followed a continuum of disease severity. Logistic regression analyses showed that attachment loss was associated with higher age, female gender, infrequent tooth brushing, infrequent dental visits, and attending a high school receiving governmental support.

CONCLUSIONS

No sharp distinction exists between periodontal health and disease among Chilean adolescents. Higher age, poor oral hygiene, and a lower socioeconomic background play a role in the occurrence of clinical attachment loss.

Absence of a specific subgingival microflora in adults with Down's syndrome

BACKGROUND

Periodontal disease in Down's syndrome (DS) is generally characterized by a high degree of bone loss. Bone loss of 5 mm or more is observed in 70% of these subjects. Among DS subjects, considerable differences in disease progression occur. So far, no studies have been conducted in which specific properties of the subgingival microflora have been related to the condition observed.

AIMS

To investigate (1) the subgingival microflora in DS subjects and other mentally retarded (control) individuals which were matched to the utmost and (2) to investigate the subgingival microflora of a "low-risk" and a " high-risk" group formed in DS subjects.

MATERIAL AND METHODS

17 DS subjects and 17 control subjects were matched with respect to age, plaque level and bleeding on probing. In addition, the DS group was divided in a "low-risk" group (0-2 teeth lost due to periodontal disease n=6) and a "high-risk"group (6-13 teeth lost due to periodontal disease n=11). Prevalence and proportions of the putative periodontal pathogens Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Bacteroides forsythus, Peptostreptococcus micros, Fusobacterium nucleatum and Campylobacter rectus in the subgingival plaque were determined using anaerobic culture techniques. No differences in the prevalence of distinct suspected periodontopathic bacteria and bacterial subgingival composition between the DS group and the control group could be established. Also no differences in the prevalence of the seven investigated microbial species between the "low-risk" and the "high-risk" group were observed.

CONCLUSIONS

Because of the lack of differences in microflora between the DS group and the control group, a specific effect of the microbiological composition in the periodontal status of subjects with DS can be excluded in this population. Host factors constitute the more likely explanation of the differences observed in DS.

Periodontal disease as a specific, albeit chronic, infection: diagnosis and treatment

Periodontal disease is perhaps the most common chronic infection in adults. Evidence has been accumulating for the past 30 years which indicates that almost all forms of periodontal disease are chronic but specific bacterial infections due to the overgrowth in the dental plaque of a finite number of mostly anaerobic species such as Porphyromonas gingivalis, Bacteroides forsythus, and Treponema denticola. The success of traditional debridement procedures and/or antimicrobial agents in improving periodontal health can be associated with the reduction in levels of these anaerobes in the dental plaque. These findings suggest that patients and clinicians have a choice in the treatment of this overgrowth, either a debridement and surgery approach or a debridement and antimicrobial treatment approach. However, the antimicrobial approach, while supported by a wealth of scientific evidence, goes contrary to centuries of dental teaching that states that periodontal disease results from a "dirty mouth." If periodontal disease is demonstrated to be a risk factor for cardiovascular disease and stroke, it will be a modifiable risk factor since periodontal disease can be prevented and treated. Since the antimicrobial approach may be as effective as a surgical approach in the restoration and maintenance of a periodontally healthy dentition, this would give a cardiac or stroke patient and his or her physician a choice in the implementation of treatment seeking to improve the patient's periodontal condition so as to reduce and/or delay future cardiovascular events.

Genetic heterogeneity in Prevotella intermedia, Prevotella nigrescens, Prevotella corporis and related species isolated from oral and nonoral sites

Prevotella intermedia (43 isolates), Prevotella nigrescens (55) and Prevotella corporis (8) from oral and nonoral sites were distinguished by species-specific DNA fragments, after hybridization of DNA fragments with ribosomal RNA (ribotyping). Eight strains previously identified as P. intermedia did not have these specific fragments. P. nigrescens, P. intermedia and P. corporis formed separate clusters in dendrograms constructed using clustering with an unweighted pair group method with arithmetic averages of similarity values derived from ribotype patterns, with 10 subclusters in P. intermedia isolates and 26 in P. nigrescens. Nine groups of P. intermedia isolates and 6 of P. nigrescens shared identical patterns. Specific ribotypes or species were not associated with particular diseases when all isolates were analyzed. However, results from organisms isolated by one laboratory using consistent clinical reporting indicated that P. intermedia was associated with more severe forms of periodontitis and P. nigrescens with mild to moderate disease.

Development of a classification system for periodontal diseases and conditions

Classification systems are necessary in order to provide a framework in which to scientifically study the etiology, pathogenesis, and treatment of diseases in an orderly fashion. In addition, such systems give clinicians a way to organize the health care needs of their patients. The last time scientists and clinicians in the field of periodontology and related areas agreed upon a classification system for periodontal diseases was in 1989 at the World Workshop in Clinical Periodontics. Subsequently, a simpler classification was agreed upon at the 1st European Workshop in Periodontology. These classification systems have been widely used by clinicians and research scientists throughout the world. Unfortunately, the 1989 classification had many shortcomings including: 1) considerable overlap in disease categories, 2) absence of a gingival disease component, 3) inappropriate emphasis on age of onset of disease and rates of progression, and 4) inadequate or unclear classification criteria. The 1993 European classification lacked the detail necessary for adequate characterization of the broad spectrum of periodontal diseases encountered in clinical practice. The need for a revised classification system for periodontal diseases was emphasized during the 1996 World Workshop in Periodontics. In 1997 the American Academy of Periodontology responded to this need and formed a committee to plan and organize an international workshop to revise the classification system for periodontal diseases. The proceedings in this volume are the result of this reclassification effort. The process involved development by the Organizing Committee of an outline for a new classification and identification of individuals to write state-of-the-science reviews for each of the items on the outline. The reviewers were encouraged to depart from the preliminary outline if there were data to support any modifications. On October 30-November 2, 1999, the International Workshop for a Classification of Periodontal Diseases and Conditions was held and a new classification was agreed upon (Fig. 1). This paper summarizes how the new classification for periodontal diseases and conditions presented in this volume differs from the classification system developed at the 1989 World Workshop in Clinical Periodontics. In addition, an analysis of the rationale is provided for each of the modifications and changes.