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Periodontitis is a complex, multifactorial disease and the susceptibility is genetically determined. In the last decade a multitude of research projects on genotyping of patients and controls in search of putative genetic risk factors has been performed. The disease (phenotype) however is also dependent on the presence of environmental and lifestyle factors, and their interaction with the various genes. Many candidate genes have been proposed and studied in relation to periodontitis. Most of the studied candidate genes code for proteins that play a role in the innate immune system. Some variants of candidate genes (gene polymorphisms) in the IL1 gene cluster and the FcgammaR genes are possibly associated with periodontitis. However till today there is no strong evidence for target genes and gene polymorphisms that play a key role in the susceptibility to and severity of periodontitis. Therefore genetic testing for periodontitis is currently not indicated.

The aim of the present study is to assess teeth with periodontal bone loss, cigarette smoking and plasma cotinine levels. We enrolled 120 untreated periodontal patients with chronic periodontitis into the study. The group comprised 48 men and 72 women, ranging in age from 21 to 75 years (mean age, 42.4 years). We divided the patients into five groups based on self-reported smoking status: (1) heavy smokers (n=35); (2) light smokers (n = 17); (3) recent former smokers (n = 8); (4) long-term former smokers (n = 17); (5) non-smokers (n = 43). We calculated packyear: (number of cigarette/day/20 x years) for all smokers. Smoking status was confirmed by measurement of plasma cotinine levels in 116 subjects. Periodontal disease was assessed on a full set of periapical radiographs. The number of teeth with bone loss was scored in four categories (no bone loss, light bone loss, moderate bone loss or serious bone loss) in all patients. The results demonstrated that plasma cotinine levels correlated significantly with the number of cigarettes smoked per day. Moreover, heavy smokers had fewer teeth with no bone loss (P < 0.001) and more teeth with moderate bone loss (P < 0.001) than non-smokers. In addition, we found a negative correlation between packyears and the number of teeth with no bone loss (P < 0.04) and a positive correlation between packyears and the number of teeth with light bone loss (P < 0.005). However, we found no correlation between plasma cotinine levels and the number of teeth with bone loss. These clinical findings suggest that cigarette smoking affects the number of teeth with or without periodontal bone loss, and this effect is related to the degree of smoking exposure.

The aim of this cross-sectional study was to investigate the prevalence and several risk indicators of root cariës in 45 periodontal maintenance patients, who had been actively treated for adult periodontitis 11-22 years ago. These patients were part of a routine 3-6 monthly maintenance schedule. Active and inactive root caries and root fillings were recorded, as well as coronal caries experience. Plaque and bleeding scores, number of exposed root surfaces, rate of saliva secretion, saliva buffer capacity, S. mutans counts and Lactobacilli were also scored. From the total of 45 subjects, 37 patients (82%) showed root lesions (root caries and/or fillings), while only 8 patients were free of any root lesions. On average, there were 4.3 lesions per patient (range 0-19) in the present study. Of all damaged root surfaces, 9% were active lesions, mostly located on mandibular teeth at lingual and vestibular sites; 40% were inactive lesions often detected at vestibular sites. The remaining damaged root surfaces (51%) were restored; they were equally divided over both jaws. A higher number of root lesions was observed in those patients with > 106 S. mutans/ml saliva. Although the actual number of lesions per patient was low in relation to the large number of sites with gingival recession, the results from this cross-sectional study in periodontal maintenance patients indicate that: root cariës can be regarded as a complication in periodontal maintenance patients, that the individual number of root lesions correlate with individual dental plaque score, that a high number of root lesions is associated with counts of salivary S. mutans, and that no relation between root cariës and coronal caries experience, salivary secretion rate or salivary buffering capacity seems present. Therefore, repeated oral hygiëne instructions and adjunctive preventive measures including diet counseling and fluoride rinses, as well as fluoride and chlorhexidine varnishes, should be advocated in high-risk patients.

Background: Periodontitis is a common, often undiagnosed, chronic infection of the supporting tissues of the teeth, epidemiologically associated with cardiovascular diseases. Since C-reactive protein (CRP) and other systemic markers of inflammation have been identified as risk factors for cardiovascular diseases, we investigated whether these factors were elevated in periodontitis., Methods: Consecutive adult patients with periodontitis (localized n = 53; generalized n = 54), and healthy controls (n = 43), all without any other medical disorder, were recruited and peripheral blood samples were taken., Results: Patients with generalized periodontitis and localized periodontitis had higher median CRP levels than controls (1.45 and 1.30 versus 0.90 mg/L, respectively, P = 0.030); 52% of generalized periodontitis patients and 36% of the localized periodontitis patients were sero-positive for interleukin-6 (IL-6), compared to 26% of controls (P= 0.008). Plasma IL-6 levels were higher in periodontitis patients than in controls (P = 0.015). Leukocytes were also elevated in generalized periodontitis (7.0 x 10(9)/L) compared to localized periodontitis and controls (6.0 and 5.8 x 10(9)/L, respectively, P= 0.002); this finding was primarily explained by higher numbers of neutrophils in periodontitis (P= 0.001). IL-6 and CRP correlated with each other, and both CRP and IL-6 levels correlated with neutrophils. The current findings for periodontitis were controlled for other known factors associated with cardiovascular diseases, including age, education, body mass index, smoking, hypertension, cholesterol, and sero-positivity for CMV, Chlamydia pneumoniae, and Helicobacter pylori., Conclusions: Periodontitis results in higher systemic levels of CRP, IL-6, and neutrophils. These elevated inflammatory factors may increase inflammatory activity in atherosclerotic lesions, potentially increasing the risk for cardiac or cerebrovascular events.

Background: Two genotypes can be distinguished within the species Peptostreptococcus micros: a smooth (Sm) and a rough (Rg) type. To date no systematic study has been performed on the prevalence and proportion of both types in untreated periodontitis patients and subjects without destructive periodontal disease. Therefore, the present study was performed to investigate: 1) the relative importance of the Sm and the Rg genotype of P micros in periodontitis and gingivitis; 2) the correlation between smoking and the 2 genotypes of P micros; and 3) the systemic antibody response against the 2 genotypes in relation to the periodontal condition and smoking., Methods: A total of 104 untreated periodontitis patients and 41 individuals with gingivitis underwent clinical examination and microbiological sampling. Pocket samples were cultured anaerobically on blood agar plates to determine the prevalence and proportion of the Sm and Rg types of P micros. Serum antibody titers against both types of P micros were determined in all subjects by enzyme-linked immunosorbent assay (ELISA) using whole bacterial cells as antigen. Additionally, in a representative group of subjects, the antigen specificity of the serum antibodies was assessed by immunoblotting experiments., Results: The prevalence of the Sm genotype was higher in subjects with periodontitis (94%) compared to subjects with gingivitis (59%), whereas the prevalence of the Rg type was not significantly different (38% versus 29%). Similar analyses were performed for subgroups of smokers and non-smokers; within the periodontitis group, the prevalence of the Sm type was not different between smokers and non-smokers (96% and 92%, respectively), whereas the prevalence of the Rg type was higher in smokers (48%) compared to non-smokers (19%). No difference in prevalence of both types was observed between smokers and non-smokers within the gingivitis group. The titers and specificity of P micros-specific immunoglobulins in periodontitis patients were not different from those in gingivitis subjects, nor were they related to smoking status or culture-positivity., Conclusions: The results of this study suggest that both the Sm and the Rg genotypes of P micros are part of the normal oral microbiota. However, the elevated prevalence of the Sm genotype in periodontitis and the elevated prevalence of the Rg type in periodontitis patients who smoke implies that both types can behave as opportunistic pathogens in destructive periodontal disease.

The aim of this cross-sectional study was to investigate cross-sectionally the prevalence and several risk indicators of root caries in 45 periodontal maintenance patients, who had been actively treated for adult periodontitis 11-22 years ago. These patients were part of a routine 3-6 monthly maintenance schedule. Active and inactive root caries and root fillings were recorded, as well as coronal caries experience. Plaque and bleeding scores, number of exposed root surfaces, rate of saliva secretion, saliva buffering capacity, mutans streptococci counts and Lactobacilli were also scored. From the total of 45 study subjects, 37 patients (82%) showed root lesions (root caries and/or root fillings), while only 8 patients were free of any root lesions. On average, there were 4.3 root lesions per patient (range 0-19) in the present study. 10 patients had active root caries lesions. Of all damaged root surfaces, 9% were active lesions, mostly located on mandibular teeth at lingual and vestibular sites: 40% were inactive lesions often detected at vestibular sites. The remaining damaged root surfaces (51%) were restored; they were equally divided over both jaws. A higher number of root lesions was observed in those patients with >106 mutans streptococci/ml saliva. Although the actual number of lesions per patient was low in relation to the large number of sites with gingival recession, the results from this cross-sectional study in periodontal maintenance patients indicate that: (1) root caries can be regarded as a complication in periodontal maintenance patients; (2) the individual number of root lesions correlate with individual dental plaque scores; (3) a high number of root lesions is associated with high counts of salivary mutans streptococci; (4) no relation between root caries and coronal caries experience, salivary secretion rate or salivary buffering capacity seems present. Therefore, repeated oral hygiene instructions and adjunctive preventive measures including diet counseling and fluoride rinses, as well as fluoride and chlorhexidine varnishes, should be advocated in high-risk patients.

Previous research has shown that probing force and probe tine shape influence the clinically assessed probing depth. The purpose of the present study was to investigate the effect of tine shape and probing force on probe penetration, in relation to the microscopically assessed attachment level in untreated periodontal disease. In 22 patients, scheduled for partial or full mouth tooth extraction and no history of periodontal treatment, 135 teeth were selected. At mesial and distal sites of the teeth reference marks were cut. Three probe tines, mounted in a modified Florida Probe handpiece, were tested: a tapered, a parallel and a ball-ended; tip-diameter 0.5 mm. The three tines were distributed at random over the sites. At each site increasing probing forces of 0.10 N, 0.15 N, 0.20 N, 0.25 N were used. After extraction, the teeth were cleaned and stained for connective tissue fiber attachment. The distance between the reference mark and the attachment level was determined using a stereomicroscope. The results showed that the parallel and ball-ended tine measured significantly beyond the microscopically assessed attachment level at all force levels; with increasing forces, the parallel tine measured 0.96 to 1.38 mm and the ball-ended tine 0.73 to 1.06 mm deeper. The tapered tine did not deviate significantly from the microscopic values at the forces of 0.15, 0.20 and 0.25 N. It can be concluded that for the optimal assessment of the attachment level in inflamed periodontal conditions, a tapered probe with a tip diameter of 0.5 mm and exerting a probing force of 0.25 N may be most suitable.

The objective of this study was to evaluate the effect of the tine shape of 3 different periodontal probes. One tapered, one parallel-sided and one WHO-probe tine, each with a diameter of 0.5 mm at the tip, were mounted in hinged handles exerting a constant probing force (Brodontic). The handles were adjusted to either 0.25 N (127 N/cm2) or 0.5 N (255 N/cm2). 12 patients with moderate to severe periodontitis were measured after supra- and subgingival debridement, using all 6 possible tine/force combinations in 3 sessions. In each session one tine/force combination was used in the 1st and 3rd quadrants, and another tine/force combination in the 2nd and 4th quadrant. The measurements in the same quadrants could therefore be used for comparisons within the same site. The selection for the 2 quadrants in which a given tine/force combination was to be used, was randomised. Calculations of differences (mean per patient) between probing measurements show that the WHO tine yields deeper recording than the parallel/sided and tapered tines, both at 127 N/cm2 and 255 N/cm2. We conclude that in addition to probing force, the tine shape of a periodontal probe is of significant importance for the recorded probing depth.

An overview is given of typing methods for bacteria that are associated with periodontitis. Special attention is paid to new molecular biological techniques, based on the characterization of protein and DNA. Bacteria that are associated with periodontitis have a population structure similar to that of opportunistic bacteria. Typing methods are used to study transmission of bacteria. P. gingivalis can be transmitted between spouses, but transmission from parent to child seems to be uncommon. A. actinomycetemcomitans transmission between adults does not occur frequently, while transmission from parent to child can occur in a low frequency.

Porphyromonas endodontalis strains ATCC 35406, HG 181, and HG 413 were cultured in an enriched broth medium, and growth curves were determined. Total membrane protein profiles of cells, harvested either from exponential phase or from stationary phase of growth, were studied by sodium dodecyl sulfate polyacrylamide-gel electrophoresis. The protein profiles indicated that the three strains shared three major proteins, designated A, B, and C, with molecular masses of 59, 43, and 41 kDa, respectively. In addition, the strains showed homology among the majority of the minor proteins. However, some minor proteins were unique for each strain. Two common minor proteins with molecular masses of 56 and 51 kDa were weakly expressed or absent in membrane preparations from cells of the early exponential phase, while they were present in membrane preparations from cells harvested in the late phase of growth. The major and minor membrane proteins may play a role in the interaction between P. endodontalis and the host. In addition, the membrane proteins may play an important role in the physiology of this endodontic pathogen.

The effect of serum bactericidal antibody on colonization with non-typable Haemophilus influenzae (NTHI) was studied in 26 children. Serum bactericidal antibody did not prevent colonization with NTHI in the nasopharynx. Antibody was present in 53% before, 91% during and 100% after documented colonization of the nasopharynx with NTHI. In addition, 5 children with recurrent otitis media with effusion (OME) due to NTHI were observed for bactericidal serum antibody during a 4-year period. Bactericidal antibody against the causative NTHI strain was not detected in the acute sera of any patient during each episode, but was observed in the convalescent sera of all of the patients. The bactericidal antibody in the convalescent serum did not appear to be protective against colonization and recurrence of disease by a different heterologous strain of NTHI. However, bactericidal antibody was augmented in some cases by a heterologous infection with NTHI. We confirmed the emergence of new strains of NTHI with DNA fingerprinting and outer membrane protein (OMP) analysis. The data suggest that the immune response to NTHI in OME is usually strain-specific, and furthermore, the results demonstrate that strain-specific bactericidal antibody does not prevent colonization in the nasopharynx with the homologous or heterologous bacterial strains. In general, bactericidal antibody is not cross-protective against heterologous strains of NTHI causing a second or third episode of otitis media with NTHI.

Recent studies of microbial epidemiology emphasizing the genetic organization and distribution of organisms associated with orofacial infections have led to new insights into the possible origins of pathogenicity. Studies into genetic heterogeneity, acquisition and transmission of these organisms have been markedly advanced by the utilization of the powerful technique of genomic DNA fingerprinting. Characteristic fingerprints for each bacterial isolate can be produced by cleavage of high molecular weight genomic DNA by restriction endonucleases. It is assumed that each DNA fingerprint represents a clonal type. In this report, we review and analyze studies of the epidemiology of bacteria associated with orofacial infections with an emphasis on periodontal disease. Studies of nontypable (NT) Haemophilus influenzae associated with recurrent otitis media illustrate the utility of this technique. DNA fingerprinting clearly demonstrates genetic heterogeneity of NT H. influenzae isolates, and clonality of infection of any individual. Furthermore, DNA fingerprinting has shown that the same clonal type is seen in siblings concurrently suffering from otitis media, suggesting horizontal transmission within the family. Studies of mutans Streptococci also show extensive genetic heterogeneity and show vertical transmission of a predominant clonal type only from mother to infant, but not from father to infant. Studies of Actinobacillus actinomycetemcomitans show considerable genetic heterogeneity among monkey isolates. Thus far, three clonal types have been reported with DNA fingerprinting among isolates from periodontal patients, but additional genetic heterogeneity can be found using specific DNA fragments as probes in hybridization experiments. Intrafamilial transmission of A. actinomycetemcomitans has been demonstrated. Porphyromonas (Bacteroides) gingivalis shows extensive genetic heterogeneity and case reports suggest clonal infection of any one individual. In contrast, results with DNA fingerprinting of Eikenella corrodens, Fusobacterium nucleatum, and Bacteroides intermedius show that individuals may be infected with 2 or more clonal types. These studies point to the great potential of DNA fingerprinting for investigating the epidemiology of putative orofacial pathogens. Such studies with periodontal microorganisms will likely reveal steps in the acquisition, intraoral and person-to-person transmission, which then could possibly be inhibited or interfered with to prevent periodontal disease or its recurrence.

Isolates of nontypable haemophilus influenzae (NTHI) recovered from paired nasopharyngeal (NP) and middle ear (ME) fluid cultures performed simultaneously on seven children with otitis media with effusion (OME) were studied by analysis of the restriction fragment patterns produced from total genomic DNA. This method provides a sensitive measure of the genetic similarities between strains. In the seven pairs examined, the NP and ME strains were indistinguishable from one another, whereas each pair was distinct from the other, except for two siblings in whom all four strains were identical. This information provides evidence that the pathogenesis of OME caused by NTHI involves spread of the bacteria from NP to the ME. Analysis of paired NP and ME isolates from three children with recurrent OME caused by NTHI indicated that the second episode was caused by the reinfection with a different strain rather than persistence and reemergence of the first strain. Finally, DNA analysis of strains from two siblings with concurrent OME suggested that person-to-person transmission of NTHI can occur among children. These findings suggest that at any one time the NTHI population in the NP is relatively homogenous, at least at the time of acute upper respiratory disease. Our observation that the strains present at the second episode of otitis media were different than the strains present in the first episode is consistent with strain replacement in the NP. Restriction fragment mapping analysis of genomic DNA of NTHI could provide a powerful tool for investigating the rate of turnover of the NTHI population in the NP.