Low prevalence of multi-resistant bacteria in undergraduate dental students; an observational case-control multi-centre study in Europe

Objective: This study assessed the prevalence of MRSA, ESBL and VRE in students from four dental schools in Europe.

Methods: The hand, tongue and nostrils of the students who treated patients (study group) and who did not treat patients (control group) were sampled. After incubation in TSB and subculturing in the presence of 4 µg/ml oxacillin, positive cultures were identified for Staphylococcus aureus by Mannitol salt agar and agglutination tests. The presence of MRSA was confirmed by specific PCR on the species and on the SSCmec genes. ESBL and VRE were isolated using specific CHROMagar and confirmed using antibiotic sensitivity tests.

Results: Of the 879 students who participated in this study (454 students which treated patients, 425 controls) a total of 50 students (5.7%) tested positive for a multi-drug resistant bacterium (MDRB); 13 (1.5%) students tested positive for MRSA, 26 (3.0%) for ESBL and 12 (1.4%) for VRE. No statistically significant differences were found between the students who treated patients compared to the control group for any of the MDRB and study centres, excluding MRSA carriage in the Italian student population. The use of antibiotics the year before sampling, was positively associated with the presence of an MDRB (OR 2.0; 95% Confidence Interval 1.10–3.68; p = 0.02).

Conclusion: The risk for MDRB carriage and sequential transmission of MDRB for dental health care students and their patients were acceptably low.

Immediate clinical and microbiological evaluation of the effectiveness of 0.5% versus 3% sodium hypochlorite in root canal treatment: A quasi-randomized controlled trial

AIM

To test the hypothesis that in the daily routine of a specialist clinic in endodontics that irrigation during root canal preparation with 3.0% NaOCl will result in fewer postoperative samples with cultivable bacteria than irrigation with 0.5% buffered NaOCl but, at the same time, will not result in a higher frequency of postoperative pain nor swelling.

METHODOLOGY

Two hundred ninety-eight patients were enrolled in the study and were randomly assigned into two groups - 0.5% NaOCl and 3% NaOCl. All endodontic diagnoses were included. Root canal treatment was performed, and bacterial sampling was carried out prior to root filling. The patients were requested to complete a form regarding pain and swelling seven days postoperatively. Fisher's exact test, Mann-Whitney U-test, Mantel-Haenszel chi-squared and the chi-squared test with a significance level of P < 0.05 were used for statistical analysis. Multivariable logistic regression was used to adjust for confounders.

RESULTS

In the 0.5% NaOCl group, 18 (13.4%) of the root canal samples were positive; in the 3% NaOCl group, the corresponding number was 24 (18.6%). The mean difference of -5.2% (95% CI: -14.8 to 4.4) was not significant (P = 0.33). In the 0.5% NaOCl group, 57 (53.8%) patients reported some pain; in the 3% group, the corresponding number was 56 (53.3%). The mean difference of 0.4 (95% CI: -14.0 to 14.8) was not significant (P = 1.0). In the 0.5% NaOCl group, 5 (5.1%) patients reported swelling; in the 3% NaOCl group, the corresponding number was 18 (17.8%). The mean difference was 12.7 (95% CI: 3.1-22.4), which was significant (P = 0.0084).

CONCLUSIONS

The difference in the concentration of NaOCl (0.5% vs 3%) had no significant impact on the number of positive cultures and did not influence either the frequency or the magnitude of postoperative pain. A significantly higher incidence of postoperative swelling was recorded for patients who received a greater concentration of NaOCl (3%).

Hydrogen sulfide production from subgingival plaque samples

Periodontitis is a polymicrobial anaerobe infection. Little is known about the dysbiotic microbiota and the role of bacterial metabolites in the disease process. It is suggested that the production of certain waste products in the proteolytic metabolism may work as markers for disease severity. Hydrogen sulfide (H2S) is a gas produced by degradation of proteins in the subgingival pocket. It is highly toxic and believed to have pro-inflammatory properties. We aimed to study H2S production from subgingival plaque samples in relation to disease severity in subjects with natural development of the disease, using a colorimetric method based on bismuth precipitation. In remote areas of northern Thailand, adults with poor oral hygiene habits and a natural development of periodontal disease were examined for their oral health status. H2S production was measured with the bismuth method and subgingival plaque samples were analyzed for the presence of 20 bacterial species with the checkerboard DNA-DNA hybridization technique. In total, 43 subjects were examined (age 40-60 years, mean PI 95 ± 6.6%). Fifty-six percent had moderate periodontal breakdown (CAL > 3 < 7 mm) and 35% had severe periodontal breakdown (CAL > 7 mm) on at least one site. Parvimonas micra, Filifactor alocis, Porphyromonas endodontalis and Fusobacterium nucleatum were frequently detected. H2S production could not be correlated to periodontal disease severity (PPD or CAL at sampled sites) or to a specific bacterial composition. Site 21 had statistically lower production of H2S (p = 0.02) compared to 16 and 46. Betel nut chewers had statistically significant lower H2S production (p = 0.01) than non-chewers. Rapid detection and estimation of subgingival H2S production capacity was easily and reliably tested by the colorimetric bismuth sulfide precipitation method. H2S may be a valuable clinical marker for degradation of proteins in the subgingival pocket.

Caries risk assessment. A systematic review

OBJECTIVE

To assess the ability of multivariate models and single factors to correctly identify future caries development in pre-school children and schoolchildren/adolescents.

STUDY DESIGN

A systematic literature search for relevant papers was conducted with pre-determined inclusion criteria. Abstracts and full-text articles were assessed independently by two reviewers. The quality of studies was graded according to the QUADAS tool. The quality of evidence of models and single predictors was assessed using the GRADE approach.

RESULTS

Ninety original articles fulfilled the inclusion criteria. Seven studies had high quality, 35 moderate and the rest poor quality. The accuracy of multivariate models was higher for pre-school children than for schoolchildren/adolescents. However, the models had seldom been validated in independent populations, making their accuracy uncertain. Of the single predictors, baseline caries experience had moderate/good accuracy in pre-school children and limited accuracy in schoolchildren/adolescents. The period of highest risk for caries incidence in permanent teeth was the first few years after tooth eruption. In general, the quality of evidence was limited.

CONCLUSIONS

Multivariate models and baseline caries prevalence performed better in pre-school children than in schoolchildren/adolescents. Baseline caries prevalence was the most accurate single predictor in all age groups. The heterogeneity of populations, models, outcome criteria, measures and reporting hampered the synthesis of results. There is a great need to standardize study design, outcome measures and reporting of data in studies on caries risk assessment. The accuracy of prediction models should be validated in at least one independent population.

Bacterial flora of the human oral cavity, and the upper and lower esophagus

This reference study aims to survey the bacterial flora of the healthy lower human esophagus and to compare it with that of the upper esophagus and oral mucosa. The use of biopsies, in addition to brush samples, allows inclusion of not only transient bacteria present on the surface but also bacteria residing in the epithelia, and the yield of the two methods can be compared. Forty patients scheduled for surgery for reasons with no known influence on esophageal flora and with no symptoms or endoscopic signs of esophageal disease were included. Samples were collected from the oral, upper esophageal, and lower esophageal mucosa using sealed brushes and biopsy forceps. Colonies cultivated on agar plates were classified and semiquantified. Twenty-three different bacterial species were identified, with similar strains present at the three sites. The most common group of bacteria was viridans streptococci, with an occurrence rate in brush samples and biopsies of 98% and 95%, respectively. The median number of species occurring in the oral cavity, upper esophagus, and lower esophagus was between 3 and 4 (range 0-7). The total number of species in the oral cavity was significantly higher when compared with either level in the esophagus, while the yields obtained by brush and biopsy sampling were highly correlated. Hence, the normal human esophagus is colonized with a resident bacterial flora of its own, which has similarities to that of the oral mucosa. There are diverse species that make up this flora, although in relatively low amounts. The most frequent inhabitants of the esophagus are streptococci, with an occurrence rate in brush samples and biopsies of 95-98%. Comparative studies of patients with eosinophilic esophagitis and gastroesophageal reflux disease are warranted.

Lactobacillus and Bifidobacterium species do not secrete protease that cleaves the MUC2 mucin which organises the colon mucus

The colon epithelium is covered by two layers of mucus built around the MUC2 mucin. An inner dense and attached mucus layer does not allow bacteria to penetrate, thus keeping the epithelial cell surface free from bacteria. An outer loose mucus layer is the habitat for the commensal bacterial microbiota. The inner mucus layer is renewed from the epithelial side and gets converted into the outer layer due to proteolytic cleavages by host proteases. We have now analysed if potential probiotic bacteria, namely Lactobacillus brevis, Lactobacillus plantarum, Lactobacillus bulgaricus and Bifidobacterium lactis, can secrete protease that cleaves the MUC2 mucin. We found that none of the potential probiotic bacteria Lactobacillus and Bifidobacterium could cleave the MUC2 core protein in the form of recombinant MUC2 N and C-termini although they secreted active proteases. This was in contrast to crude mixtures of oral and faecal bacteria that cleaved the MUC2 mucin. This observation further supports the view that these potential probiotic bacteria are of no harm to the host, as these bacteria cannot disrupt the mucin organised mucus as long as they are covered by glycans.

Clinical and microbiological characteristics of peri-implantitis cases: a retrospective multicentre study

OBJECTIVES

The aim of this study was to follow patient cases retrospectively in a longitudinal manner from the time of implant placement to the time they were diagnosed with peri-implant disease, and to identify associated clinical and microbiological features of peri-implant disease.

MATERIAL AND METHODS

A total of 281 patient cases were chosen from the archives of the Oral Microbiological Diagnostic Laboratory, Gothenburg, Sweden, based on bacterial samples taken from diseased implants. A form was designed and filled in separately for each case including data on patient, implant and disease profile.

RESULTS

Most cases were severe peri-implantitis cases (91.4%). In 41.3% of the patients, peri-implantitis was developed early, already after having implants in function less than 4 years. The type of implant surface was significantly associated with the time in years implants were in function, before disease was developed (P < 0.05). The microbiological results by both culture and checkerboard analysis, although failed to fully correspond to the severity of the disease in terms of magnitude, proved to show that peri-implantitis is a polymicrobial anaerobic infection with increased number of AGNB (aerobic Gram-negative bacilli) in 18.6% of the patients.

CONCLUSIONS

Peri-implantitis is a biological complication of implants in function that poses a threat to their long-term survival. It may develop earlier around implants with rough surfaces and it may represent a true infection. Microbiological sampling methods should be improved and uniformed so as to fully unveil the microbiological profile of the disease.

Metal-ion susceptibility of oral bacterial species

AIMS

This study aimed to evaluate the effect of lead (Pb) on growth of bacterial species related to dental diseases in vitro.

METHODS AND RESULTS

The effects of lead acetate on representative species of the oral flora were examined at 0.1-10 mmol l(-1) and compared with the effect of silver nitrate and ferrous sulfate. The minimal inhibitory concentration of lead acetate was between 0.15 and 5 mmol l(-1) for the bacterial strains tested. The minimal bactericidal concentration of lead acetate for most oral species was detected in the range of 5-10 mmol l(-1). Silver nitrate at a concentration of 1.25 mmol l(-1) was sufficient to exhibit antibacterial activity against almost all bacteria tested. Ferrous sulfate had the lowest effect.

CONCLUSIONS

The study indicated a general antimicrobial effect of lead on oral bacterial species in the range of 0.15-10 mmol l(-1). The toxicity of silver nitrate was the highest, whereas that of ferrous sulfate was the lowest. Gram-positive species had a tendency to be less susceptible for metals than Gram-negatives.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study shows that it is possible that microbiological changes may occur in the dental plaque in children because of toxic exposure of environmental lead.

Lactobacillus species and genotypes associated with dental caries in Thai preschool children

Lactobacilli have been associated with the presence and progression of dental caries. Nevertheless, the relation between certain species or genotypes of Lactobacillus and caries is unclear and there are no data available for the Thai population. This study aimed to examine the distribution of species and genotypes of oral Lactobacillus among children with rather high caries prevalence, and to investigate whether certain species or genotypes were more related to caries activity than others. One hundred and sixty-five children were examined for caries status. Saliva samples were collected and the numbers of lactobacilli were counted. A total of 357 Lactobacillus isolates from 59 children were identified to species level by 16S ribosomal RNA genes polymerase chain reaction (PCR) -restriction fragment length polymorphism and 16S ribosomal RNA gene sequencing. Furthermore, 304 isolates from 56 children were genotyped using arbitrarily primed PCR. Significant correlation was found between levels of lactobacilli and dental caries (P < 0.001). Among the 10 identified species of Lactobacillus, L. salivarius was more prevalent in children with moderate to high caries prevalence compared with children with low caries prevalence, while L. fermentum was the most predominant species in all study groups. Moreover, a genetic heterogeneity of Lactobacillus species was found among the children and those with high caries prevalence tended to be colonized with more than one clonal type. In summary, L. salivarius may be a putative caries pathogen among preschool Thai children.

Oral Lactobacillus species in type 2 diabetic patients living in southern Thailand

Although lactobacilli are part of normal oral, gastrointestinal and genitourinary flora, they are an uncommon cause of infections in human. Lactobacillus-associated infections have generally occurred in patients with serious underlying conditions e.g. diabetes and cancer that might favour certain microorganisms. The aim of this study was to characterize species and genotypes of lactobacilli isolated from diabetic patients and non-diabetic subjects. One hundred and five type 2 diabetic patients and 103 non-diabetic subjects were recruited in this study. A total of 170 isolates of Lactobacillus were identified using 16S rRNA gene PCR-RFLP and genotyping were performed using AP-PCR by ERIC primers. It was found that type 2 diabetic patients had a significantly higher prevalence (p = 0.008) and level of lactobacilli than non-diabetic controls (p = 0.030). The most frequently isolated Lactobacillus spp. were L. casei/paracasei and L. fermentum in both the diabetic and non-diabetic groups. Strains of L. casei/paracasei and L. fermentum from between and within individuals were genotyped, and the genotyping of Lactobacillus strains showed diversity between individuals. One up to three genotypes of these two species could be found in the same subject. Interestingly, fewer genotypes were found in the diabetic patients than in the non-diabetic subjects.

A retrospective study on the microbiology in patients with oral complaints and oral mucosal lesions

OBJECTIVE

The aim of this study was to microbiologically analyze oral mucosal samples collected during 2 years from patients with oral mucosal complaints.

MATERIALS AND METHODS

Mucosal scraping samples were taken from 297 patients and semiquantified by culture for detection of opportunistic microorganisms e.g. Staphylococcus aureus, enterococci, aerobic Gram-negative bacilli (AGNB) and yeasts. Antibiotic susceptibility test was performed.

RESULTS

Altogether 297 patients were sampled (mean age 56.8 +/- 20.7). Among the 110 patients with known medical condition, 48 were systemically immunocompromised, 35 had systemic diseases, and 27 had only local oral complaints. Opportunists in moderate growth or more were present commonly in all three groups and most frequent in the immunocompromised patients (66.7%). Candida species were the most frequent opportunist (68.8%), however, their level was low and combinations with bacterial opportunists were common (39.6%). All bacterial opportunists tested were antibiotic multiresistant. Follow-up samples were collected in 23 cases out of which seven showed still presence of opportunists in heavy growth despite repeated treatment with ciprofloxacin.

CONCLUSIONS

This study showed a frequent presence of bacterial and fungal opportunists in patients with oral mucosal complaints, which were most common in immunocompromised individuals, however, also frequent in patients with local oral complaints only. Systematic evaluation of different treatment strategies is needed.

Pre-beta1-lipoprotein and Lp(a) antigen in relation to triglyceride levels and insulin release following an oral glucose load in middle-aged males

A series of 30 previously investigated and presumably healthy middle-aged males have been studied, following an oral glucose tolerance test (OGTT). The insulin mean value 120 min after the start of the OGTT was found to be significantly lower in persons possessing the pre-beta1-lipoprotein (pre-beta1 +) and Lp(a) antigen, than in those who were pre-beta1-/Lp(a-). At 60 min during the OGTT, triglyceride and insulin correlated significantly in pre-beta1-/Lp(a-) individuals, but not in pre-beta1 + or Lp (a+) individuals; on the other hand, insulin correlated significantly with blood glucose at this time in the pre-beta1 + and Lp(a+) individuals, but not in the pre-beta1-/Lp(a-). These findings may reflect an important biochemical difference between the two subpopulations.

Genotypic characterization of Porphyromonas gingivalis isolated from Swedish patients with periodontitis and from periodontal abscesses

INTRODUCTION

A significant genetic polymorphism has been shown for Porphyromonas gingivalis isolates from different geographical areas. It is, however, possible that genetic similarities can be found among isolates obtained from a more specific population. The aim of the present study was to evaluate genetic heterogeneity among P. gingivalis isolates obtained from Swedish subjects with chronic periodontitis and from periodontal abscess lesions.

METHODS

A total of 78 P. gingivalis strains, including 55 fresh clinical isolates obtained from 52 Swedish periodontitis subjects, eight isolates from eight Swedish periodontal abscess subjects and 15 reference strains, were subjected to amplified fragment length polymorphism (AFLP) and random amplified polymorphic DNA (RAPD) genotyping assays.

RESULTS

A total of 62 AFLP genotypes and 70 RAPD genotypes were identified among the 78 P. gingivalis strains. Forty-six strains were clustered at 70% similarity level into 15 clusters. Six identical RAPD genotypes were identified among the strains. The AFLP/RAPD profiles were compared for identical genotypes. A total of 56 AFLP/RAPD genotypes were found. Four pairs of identical AFLP/RAPD genotypes were found for two strains obtained from two different periodontal pockets each of four subjects. Interestingly, two strains showed an RAPD/AFLP genotype, which was identical to the type strain W83.

CONCLUSION

The present study demonstrated that Swedish P. gingivalis isolates exhibit a wide variety of genotypes with only a weak clustering pattern. No predominant genotype at the whole chromosomal DNA level was present among Swedish P. gingivalis strains.

Response to alkaline stress by root canal bacteria in biofilms

AIM

To determine whether bacteria isolated from infected root canals survive alkaline shifts better in biofilms than in planktonic cultures.

METHODOLOGY

Clinical isolates of Enterococcus faecalis, Lactobacillus paracasei, Olsenella uli, Streptococcus anginosus, S. gordonii, S. oralis and Fusobacterium nucleatum in biofilm and planktonic cultures were stressed at pH 10.5 for 4 h, and cell viability determined using the fluorescent staining LIVE/DEAD BacLight bacterial viability kit. In addition, proteins released into extracellular culture fluids were identified by Western blotting.

RESULTS

Enterococcus faecalis, L. paracasei, O. uli and S. gordonii survived in high numbers in both planktonic cultures and in biofilms after alkaline challenge. S. anginosus, S. oralis and F. nucleatum showed increased viability in biofilms compared with planktonic cultures. Alkaline exposure caused all planktonic cultures to aggregate into clusters and resulted in a greater extrusion of cellular proteins compared with cells in biofilms. Increased levels of DnaK, HPr and fructose-1,6-bisphosphate aldolase were observed in culture fluids, especially amongst streptococci.

CONCLUSIONS

In general, bacteria isolated from infected roots canals resisted alkaline stress better in biofilms than in planktonic cultures, however, planktonic cells appeared to use aggregation and the extracellular transport of specific proteins as survival mechanisms.

Phenotypes, serotypes and antibiotic susceptibility of Swedish Porphyromonas gingivalis isolates from periodontitis and periodontal abscesses

This study was conducted to reveal phenotypic, serological subtypes and antibiotic susceptibility among fresh isolates of Porphyromonas gingivalis in a Swedish population with periodontitis and periodontal abscess. Fifty-five subgingival strains were isolated and tentatively designated as P. gingivalis from 55 consecutive paper-point samples taken from 51 patients with periodontitis (at least one site with >6-mm pocket depth) in Sweden and were sent in for microbiological evaluation. Eight P. gingivalis strains from periodontal abscesses were also included. Four P. gingivalis strains served as reference and another four type strains were included. The strains were characterized by colony morphology, biochemical tests, enzyme profile, gas-liquid chromatography and antibiotic susceptibility. The strains were further characterized for whole cell protein profiles using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and were identified to serotype by specific monoclonal antibodies. Among the 55 P. gingivalis strains 35 had smooth (S), 13 rough (R) and seven semi-rough colony morphologies. All strains were phenotypically homogeneous in biochemical tests, enzyme profile and antibiotic susceptibility. All strains produced phenylacetic acid and alpha-fucosidase. Almost all (96%) of the subgingival strains, but relatively fewer (62%) of the abscess strains, belonged to serotype A. Two subgingival and three abscess strains were classified as serotype B. No specific SDS-PAGE protein profiles were recorded for the two serotypes. The P. gingivalis strains from Swedish periodontitis cases showed homogeneity in terms of biochemical phenotypes and antibiotic susceptibility patterns. The strains fell into two serotypes, of which serotype A predominated in the periodontitis cases and serotype B was overrepresented in periodontal abscesses.

Fcgamma receptor polymorphisms and periodontal status: a prospective follow-up study

AIMS

The aims of this study were to assess: (i) the distribution of Fcgamma receptor polymorphisms among patients with chronic periodontitis ("cases") and control subjects with no/minimal loss of periodontal tissue support in a Caucasian population; (ii) whether these polymorphisms can serve as severity markers for periodontitis; and (iii) whether they have any bearing on the response to periodontal therapy.

METHODS

The study sample consisted of 132 cases and 73 controls of comparable age and gender. Full-mouth periodontal status was assessed. Subgingival plaque (PL) samples and blood samples were obtained and analysed with respect to 19 bacterial species and homologous serum immunoglobulin G titres. Polymorphisms in the Fcgamma receptor IIa (131R/H) and IIIb (NA1/NA2) were assessed by polymerase chain reaction. Patients underwent periodontal therapy and were followed up at 4 and 30 months.

RESULTS

Neither polymorphism showed a skewed distribution among cases and controls. At baseline, periodontitis patients with Fcgamma RIIa-H/H131 genotype had more PL and deeper pockets than patients in other genotype groups (p < 0.05). Both bacterial levels and antibody titres were unrelated to genotype. The longitudinal analysis failed to detect an association between genotype and response to periodontal therapy.

CONCLUSIONS

The present data failed to demonstrate a clinically relevant relationship between the Fcgamma receptor IIa (131R/H) or IIIb (NA1/NA2) polymorphism and periodontal status.

Use of polymerase chain reaction techniques and sodium dodecyl sulfate-polyacrylamide gel electrophoresis for differentiation of oral Lactobacillus species

BACKGROUND/AIMS

The genus Lactobacillus has been associated with dental caries in humans, although it is seldom speciated due to lack of simple and nonlaborious identification methods. A considerable heterogeneity among Lactobacillus species has been demonstrated. The purpose of this study was to develop simple methods combining restriction fragment length polymorphism analysis of polymerase chain reaction (PCR)-amplified 16S rRNA (16S rRNA gene PCR-RFLP) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) for the identification of 13 reference strains of Lactobacillus.

METHODS

The 16S rRNA gene sequences were amplified by PCR using universal primers and digestion of PCR products with the restriction endonucleases, HpaII and HaeIII. The 16S rRNA gene PCR-RFLP is reproducible and has been proved to be useful for differentiating Lactobacillus strains to species level. Seventy-seven Lactobacillus isolates from a Thai population were used to show the applicability of the identification test.

RESULTS

PCR-RFLP alone had limitations, because the RFLP patterns of Lactobacillus casei and Lactobacillus rhamnosus and of Lactobacillus acidophilus and Lactobacillus crispatus showed similar patterns; however, these could be differentiated by SDS-PAGE. Of the 77 isolates, 38 were identified as Lactobacillus fermentum, 25 as L. rhamnosus, 5 as Lactobacillus salivarius, 5 as L. casei, 3 as L. acidophilus and 1 as Lactobacillus plantarum.

CONCLUSION

16S rRNA gene PCR-RFLP, using HpaII and HaeIII, together with SDS-PAGE protein profiles could be an alternative method for the identification of oral Lactobacillus strains to species level, and may be applicable for large-scale studies on the association of Lactobacillus to dental caries.

A new checkerboard panel for testing bacterial markers in periodontal disease

BACKGROUND/AIMS

Various microbiological methods have been used for testing bacterial markers for periodontitis and periodontal disease progression. Most studies have used only a limited number of well recognized bacterial species. The purpose of the present study was to evaluate the association of 13 more recently identified bacterial species in a new panel in comparison with 12 previously more recognized periodontotopathogens ('old panel') using the 'checkerboard' DNA-DNA hybridization method.

METHODS

Fifty individuals were chosen who showed at least one site with a probing pocket depth of 6 mm or more (disease) and bleeding on probing and at least one site with a probing pocket depth of 3 mm and without bleeding on probing (health). One diseased and one healthy site on each individual were sampled with the paperpoint technique and the samples were processed in the checkerboard technique against deoxigenin-labeled whole genomic probes to 25 subgingival species representing 12 well recognized and 13 newly identified periodontitis associated species.

RESULTS

Twenty-four (out of 25) species were detected more frequently in the subgingival plaque of diseased than healthy sites both at score 1 (> 10(4)) and score 3 (> 10(5)). A significant difference at the higher score (score 3) was noticed for all species of the old panel except for three (Streptococcus intermedius, Selenomonas noxia, and Eikenella corrodens). Of the species in the new panel only Prevotella tannerae, Filifactor alocis, and Porphyromonas endodontalis showed a statistical significant difference between diseased and healthy sites.

CONCLUSION

It was concluded that P. tannerae, F. alocis, and P. endodontalis should be added to the 12 species used for routine diagnostics of periodontitis-associated bacterial flora.

Is pre-term labour associated with periodontitis in a Danish maternity ward?

OBJECTIVES

To reveal differences in periodontal status and presence of subgingival bacteria in a Scandinavian population of women with pre-term birth compared with women who delivered at term.

MATERIALS AND METHODS

Twenty-one women with pre-term labour (before week 35) and 33 women with term labour (between weeks 38 and 41) were included in this case-control study. Periodontal measurements included plaque index (PlI), probing pocket depth (PPD) and bleeding on probing (BOP). Inter-proximal distances from the cemento-enamel junction (CEJ) to the marginal bone crest (MBC) were measured on bitewing radiographs. In 31 patients (16 cases and 15 controls) the subgingival plaque was analysed using "checkerboard" DNA-DNA hybridization.

RESULTS

Differences between the two examined groups were found related to "Twin births" (p=0.0064) and "Smokers" (p=0.03). None of the periodontal measurements showed any association. Significant differences were found concerning presence of Tannerella forsythensis, Treponema denticola, Peptostreptococcus micros, Streptococcus intermedius, Streptococcus oralis, Streptococcus sanguis and Capnocytophaga ochracea but when defining sites with >10(5) bacteria as heavily colonized, no statistical difference was found between the two groups.

CONCLUSION

A relation between pre-term birth and periodontitis was not revealed in the present study.

Virulence, phenotype and genotype characteristics of endodontic Enterococcus spp

BACKGROUND/AIMS

Enterococci have been implicated in persistent root canal infections but their role in the infection process remains unclear. This study investigated the virulence, phenotype and genotype of 33 endodontic enterococcal isolates.

METHODS

Phenotypic tests were conducted for antibiotic resistance, clumping response to pheromone, and production of gelatinase, hemolysin and bacteriocin. Genotype analysis involved polymerase chain reaction amplification of virulence determinants encoding aggregation substances asa and asa373, cytolysin activator cylA, gelatinase gelE, gelatinase-negative phenotype ef1841/fsrC, adherence factors esp and ace, and endocarditis antigen efaA. Physical DNA characterization involved pulsed-field gel electrophoresis of genomic DNA, and plasmid analysis.

RESULTS

Potential virulence traits expressed included production of gelatinase by Enterococcus faecalis (n=23), and response to pheromones in E. faecalis culture filtrate (n=16). Fourteen strains produced bacteriocin. Five strains were resistant to tetracycline and one to gentamicin, whereas all were susceptible to ampicillin, benzylpenicillin, chloramphenicol, erythromycin, fusidic acid, kanamycin, rifampin, streptomycin and vancomycin. Polymerase chain reaction products encoding efaA, ace, and asa were detected in all isolates; esp was detected in 20 isolates, cylA in six isolates, but asa373 was never detected. The gelatinase gene (gelE) was detected in all isolates of E. faecalis (n=31) but not in Enterococcus faecium (n=2); a 23.9 kb deletion sequence corresponding to the gelatinase-negative phenotype was detected in six of the eight E. faecalis isolates that did not produce gelatinase. Pulsed-field gel electrophoresis and plasmid analyses revealed genetic polymorphism with clonal types evident. Plasmid DNA was detected in 25 strains, with up to four plasmids per strain and a similar (5.1 kb) plasmid occurring in 16 isolates.

CONCLUSIONS

Phenotypic and genotypic evidence of potential virulence factors were identified in endodontic Enterococcus spp., specifically production of gelatinase and response to pheromones.

Longitudinal stability of serum immunoglobulin G responses to periodontal bacteria

BACKGROUND

The value of seroepidemiology in the study of periodontal infections has not been adequately explored. This study examined serum immunoglobulin (IgG) responses to periodontal bacteria in patients with periodontitis and periodontitis-free individuals over a 30-month period.

METHODS

Eighty-nine patients with chronic periodontitis and 42 control subjects with no deep periodontal pockets and no or minimal attachment loss (30-72 years old, 43% men) were included. Patients were examined at baseline, after completed periodontal therapy 4 months post-baseline, and at 30 months, and controls, at baseline and 30 months. IgG antibodies to 19 periodontal species were determined by checkerboard immunoblotting.

RESULTS

On average, patients displayed at baseline up to 800-fold higher titers than controls to all but three species. Over the 30-month period, titers remained stable at low levels in controls. In patients, periodontal conditions improved from a baseline mean probing depth of 3.6 mm, bleeding on probing of 62% and an average of 21.5 pockets of=6 mm/person, to 2.5 mm mean pocket depth, 30% bleeding on probing, and 1.2 deep pockets, at 30 months. Over time, antibody titers showed a modest decline in patients, but remained significantly elevated at 30 months in comparison with controls. Antibody-level changes over time were not significantly different between subjects that did and did not receive adjunctive systemic antibiotics.

CONCLUSIONS

Conspicuous differences in IgG titers to periodontal bacteria exist between periodontitis patients and periodontally healthy controls. Despite successful periodontal therapy, titers remained elevated over a 30-month period, suggesting that serology may mark the history of past periodontal infection.

Gram-positive rods prevailing in teeth with apical periodontitis undergoing root canal treatment

AIMS

To identify Gram-positive rods from root canals of teeth with apical periodontitis and to examine their associations with other species.

METHODOLOGY

Consecutive root canal samples (RCSs) from 139 teeth undergoing root canal treatment were analyzed prospectively for cultivable microbes. Gram-positive rods in the first RCS submitted after chemo-mechanical preparation were categorised to genus level by selective media and gas-liquid chromatography (GLC), and identified to species level by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Associations between organisms were measured by odds ratios (OR).

RESULTS

In the first samples submitted a total of 158 Gram-positive rods, 115 Gram-positive cocci, 26 Gram-negative rods and 9 Gram-negative cocci, were identified. At genus levels Gram-positive rods were classified into: Lactobacillus spp. (38%), Olsenella spp. (18%), Propionibacterium spp. (13%), Actinomyces spp. (12%), Bifidobacterium spp. (13%) and Eubacterium spp. (6%). The most frequent species were Olsenella uli, Lactobacillus paracasei and Propionibacterium propionicum. In subsequent samples taken during treatment, Gram-positive rods were also identified, although the number of strains was considerably reduced. Positive associations were observed between members of the genus lactobacilli and Gram-positive cocci (OR>2).

CONCLUSIONS

Olsenella uli and Lactobacillus spp. predominated over other Gram-positive rods. A possible association exists between Lactobacillus spp. and Gram-positive cocci in root canals of teeth with apical periodontitis receiving treatment.

Microbiological Evaluation of One- and Two-Visit Endodontic Treatment of Teeth with Apical Periodontitis: A Randomized, Clinical Trial

The antimicrobial efficacy of endodontic procedures performed in one-visit (including a 10-min intraappointment dressing with 5% iodine-potassium-iodide) was compared with a two-visit procedure (including an interappointment dressing with calcium-hydroxide paste). Teeth with apical periodontitis (n = 96) were randomly assigned to either group. Root canal sampling and culturing were performed before and immediately after instrumentation, and after medication. Initial sampling demonstrated the presence of microorganisms in 98% of the teeth. Postinstrumentation sampling showed reduction of cultivable microbiota. Antibacterial dressing further reduced the number of teeth with surviving microbes. In the postmedication samples, residual microorganisms were recovered in 29% of the one-visit teeth and in 36% of the two-visit treated teeth. No statistically significant differences between the groups were discerned. It was concluded that from a microbiological point of view, treatment of teeth with apical periodontitis performed in two appointments was not more effective than the investigated one-visit procedure.

Oral and intestinal microflora in 5-fluorouracil treated rats, translocation to cervical and mesenteric lymph nodes and effects of probiotic bacteria

Serious systemic infections may occur during cancer chemotherapy due to disturbances in the oropharyngeal and gastrointestinal microflora, impaired mucosal barrier functions and immunosuppression. Bacteria may spread from the gastrointestinal tract to the regional lymph nodes. The routes for bacterial spread from the oral cavity are less well known. In the present study we investigated changes in the oral and intestinal microfloras in rats given 50 mg/kg 5-fluorouracil (5-FU) i.v. for 6 days. Bacterial dissemination to the lymph nodes draining the oral cavity and the lymph nodes draining the gastrointestinal tract was examined. Effects of adding the probiotic strain Lactobacillus plantarum 299v in the drinking water to the rats were measured. 5-FU treatment caused an increase in the number of facultative and strictly anaerobic bacteria in biopsies from the oral cavity and an increase in the number of facultative anaerobes in the large intestine. The proportion of facultative gram-negative rods increased in both the oral cavity and intestine. Bacteria translocated to both the cervical and mesenteric lymph nodes in untreated animals and increased in numbers after 5-FU treatment due to an increase in the number of facultative gram-negative rods. Treatment with L. plantarum 299v improved food intake and body weight in 5-FU-treated rats. It also reduced the 5-FU-induced raise in the total numbers of facultative anaerobes in the intestine, but did not reduce translocation and did not prevent diarrhea. This study reinforces the oral cavity, along with the gastrointestinal tract, as a source for bacterial dissemination. The use of probiotic bacteria may reduce some side effects of 5-FU treatment.

Oestrogen receptor alpha gene polymorphism is related to aortic valve sclerosis in postmenopausal women

OBJECTIVES

Aortic valvular sclerosis (AS) is an inflammatory process and not a result of normal ageing. The sclerotic process is accelerated by risk factors such as smoking and high cholesterol levels. The genetic factors for the development of AS are however unknown. Therefore the purpose of the present study was to investigate whether polymorphisms in the oestrogen receptor alpha (ORalpha) gene and in the transforming growth factor beta (TGF-beta1) gene were related to the presence of AS in postmenopausal women.

DESIGN

Case-control study.

SUBJECTS AND METHODS

Relationships were tested between polymorphisms in the ORalpha gene defined by the restriction enzymes PvuII and XbaI, and in the TGF-beta1 gene defined by AocI, and AS, lipid levels, and lipoprotein(a) [Lp(a)] in 41 postmenopausal female patients and 41 age- and sex-matched controls. These polymorphisms were also tested in relation to lipid levels and Lp(a), in 99 healthy Caucasian girls, aged 16.9 +/- 1.2 years.

RESULTS

In the postmenopausal patients and age-matched controls, the PvuII polymorphism was independently associated with an increased risk of AS [odds ratio (OR) = 3.38; 95% confidence interval (CI) 1.13-10.09). A genotype defined by at least one restriction site in the PvuII polymorphism and two restriction sites in the TGF-beta1 polymorphism was related to a highly significantly increased risk of AS (OR = 4.58; 95% CI 1.68-12.51). In the adolescent female cohort, presence of two restriction sites in the PvuII polymorphism was associated with higher levels of total cholesterol (TC) (P = 0.02), and low-density lipoprotein cholesterol (LDL) (P = 0.04).

CONCLUSIONS

We have demonstrated that the PvuII polymorphism in the ORalpha gene is related to both the presence of AS in postmenopausal women and to lipid levels in adolescent females, suggesting that this polymorphism may influence the risk of AS partly by affecting lipid levels.

Bacteria recovered from teeth with apical periodontitis after antimicrobial endodontic treatment

Chávez de Paz LE, Dahlén G, Molander A, Möller A, Bergenholtz G. Bacteria recovered from teeth with apical periodontitis after antimicrobial endodontic treatment. International Endodontic Journal, 36, 500-508, 2003.

AIM

To determine whether there is a pattern for certain bacteria to remain after chemo-mechanical treatment of root canals in teeth with apical periodontitis.

METHODOLOGY

Consecutive root-canal samples of 200 teeth receiving root-canal treatment, referred from general practitioners and endodontic specialists for analyses of cultivable microbes, were studied prospectively. To be included, samples had to be taken at a treatment session subsequent to the one at which endodontic therapy was initiated. All samples were from teeth that either presented with clinical or radiographic evidence of apical periodontitis or both. Bacteriological findings were linked to clinical and radiographic parameters including status of the root canal prior to treatment, namely, vital pulp, necrotic pulp or root filled.

RESULTS

A total of 248 strains were isolated from 107 teeth giving bacterial growth. Gram-positives predominated (85%). Lactobacillus spp. (22%), nonmutans streptococci (18%), and Enterococcus spp. (12%) were the most common isolates. Gram-negative anaerobes were relatively sporadic. Large radiographic bone lesions, persistent pain and use of intracanal calcium hydroxide dressing correlated with bacterial presence (P < 0.05).

CONCLUSIONS

Once established, nonmutans streptococci, enterococci and lactobacilli appear to survive commonly following root-canal treatment of teeth with clinical and radiographical signs of apical periodontitis.

Periodontal conditions among adults in Southern Thailand

OBJECTIVE

To describe the periodontal conditions among 30-39- and 50-59-year-old rural Thais from the Province of Songkhla, Southern Thailand.

METHODS

A total of 359 dentate persons were given a clinical examination comprising recordings of plaque and calculus in six teeth, and bleeding on probing, attachment level and pocket depth in six sites of all teeth present, except third molars. The same examiner carried out all examinations. Information on religious faith, smoking habits and use of betel was obtained by interview. A subset consisting of 60 persons was reexamined for attachment level 6 months later by another examiner.

RESULTS

The oral hygiene conditions were poor with abundant amounts of both plaque and calculus. Gingival bleeding was essentially ubiquitous. The prevalence of attachment loss > or = 4 mm was 92% among 30-39-year-olds and 100% among 50-59-year-olds. The average percentage of sites affected in the two age groups was 23.9% and 63.9%. Pockets > or = 4 mm were seen in 84% of the 30-39-year-olds and in 93% of the 50-59-year-olds. Older age, Thai Buddhist faith and a high percentage of sites with calculus were significant positive predictors of a high percentage of sites with attachment loss > or = 4 mm, whereas older age and Thai Buddhist faith were the only statistically significant predictors of a high percentage of sites with attachment loss > or = 7 mm.

CONCLUSION

The results indicate that this Thai population may have more widespread and severe periodontal destruction than other Asian populations, but failed to confirm the contention that Muslim faith is associated with more severe periodontal destruction.

Periodontal microbiota and clinical periodontal status in a rural sample in southern Thailand

We sought to determine (i) the association of subgingival bacterial profiles to clinical periodontal status in a population with limited access to dental care in Thailand, and (ii) the external validity of our earlier findings from a similar study in rural China. We examined 356 subjects, 30-39 yr old and 50-59 yr old, with respect to clinical periodontal status and subgingival plaque at maximally 14 sites per subject. Checkerboard hybridizations were used to analyse a total of 4343 samples. The prevalence of the 27 species investigated ranged between 87.2% and 100%. Discriminant analysis based on microbial profiles classified correctly 67.5% of all deep (> or = 5 mm) and 64.2% of all shallow sites, and 67.4% of all subjects with and 69.3% of all subjects without > or = 3 deep pockets. High colonization by 'red complex' bacteria was four times as likely (95% Confidence Limits (CL) 2.5-6.6) in subjects with > or = 10 sites with attachment loss of > or = 5 mm, and 4.3 times as likely (95% CL 2.6-7.1) in subjects with > or = 30 such sites. The data confirmed (i) the ubiquitous prevalence of the bacteria investigated in subjects with no regular access to dental care; and (ii) the high odds for periodontal pathology conferred by increased levels of specific periodontal bacteria.

Interleukin-1 gene polymorphism and periodontal status

OBJECTIVES

This case-control study examined polymorphisms at the interleukin-1 gene in relation to periodontal status, subgingival bacteria and systemic antibodies to periodontal microbiota.

METHODS

132 periodontitis patients were age- and gender-matched with 73 periodontally intact controls. Full-mouth clinical assessments of the periodontal tissues were performed. Subgingival plaque samples (2440 in total) were analyzed by genomic DNA probes, and serum IgG antibodies to periodontal microbiota were assessed by an immunoassay. Polymorphisms in the IL-1A gene at position +4845 and the IL-1B gene at position +3953 were studied by PCR. A composite positive genotype was defined as at least one rare (#2) allele present at each locus.

RESULTS

No skewed distribution of the composite genotype was observed between cases and controls (45.2% vs 41.7%). In cases, both the composite genotype and the number of #2 alleles were positively correlated with the severity of attachment loss. No relationship between genotype and subgingival microbial profiles was observed. Genotype positive patients revealed both overall lower serum antibody levels and specific titers against selected bacteria.

CONCLUSIONS

The composite genotype failed to distinguish between periodontitis patients and controls but correlated in patients with the severity of the disease and the antibody responses to periodontal microbiota.

A protocol for polymerase chain reaction detection of Enterococcus faecalis and Enterococcus faecium from the root canal

AIM

The present study was set up to develop a protocol for detection of Enterococcus faecalis and Enterococcus faecium from the root canal.

METHODOLOGY

A collection of type strains and clinical isolates ol E. faecalis and faecium was used. Specific polymerase chain reaction (PCR) primers targeted against the 16S/23S rDNA intergenic region were used and PCR reactions were set up. PCR products were run on TBE-agarose gel and analysed. The sensitivity of the PCR systems was studied using serial dilutions of (i) bacterial DNA and (ii) bacterial cells from E. faecalis. The specificity of the identification was tested against closely related species.

RESULTS

All strains of E. faecalis and E. faecium produced identical amplicon profiles composed of two major bands corresponding to sizes of 320 and 420 bp. When amplifying DNA of higher purity, a third band of 600 bp became evident as well. Closely related species demonstrated single bands of various sizes and were easily distinguished from enterococci. The detection level of DNA from serial dilutions of DNA was 10(-13) g. The DNA extraction protocol from bacterial cell suspensions resulted in a detection level of 10 bacterial cells per sample. CONCLUSIONS The present study demonstrated a good potential for using PCR technology in the detection of F. faecalis and E. faecium from root canal samples. With a high specificity the methodology was able to detect 10 cells of E. faecalis.

Smoking and subgingival microflora in periodontal disease

AIM

The present investigation was undertaken to analyze the influence of smoking on the periodontal disease associated subgingival microflora. The population included 33 smokers and 31 non-smokers in the age range 36-86 years.

METHODS

Microbial samples were obtained from 4 sites per patient. The checker-board DNA-DNA hybridization technology was used for detection of the bacterial species P. gingivalis, P. intermedia, P. nigrescens, B. forsythus, A. actinomycetemcomitans, F. nucleatum, T. denticola, P. micros, C. rectus, E. corrodens, S. noxia and S. intermedius.

RESULTS

Using score 1 as cutoff, contrasting colonized versus non-colonized patients, 8 out of 12 species were detected in > or = 90% of both smokers and non-smokers. Using score 4 as cutoff, contrasting heavily colonized patients versus non-colonized and less heavily colonized patients, the detection rates decreased in both smokers and non-smokers. No significant differences in detection rates were observed between smokers and non-smokers. Logistic regression analysis indicated that neither smoking, probing depth nor gingival bleeding influenced the occurrence of the species analyzed. The lack of a smoking exposure dose-response further supported the indication of a limited influence of smoking.

CONCLUSION

Smoking exerts little, if any, influence on the subgingival occurrence of several of the bacteria most commonly associated with periodontal disease.

Checkerboard assessments of serum antibodies to oral microbiota as surrogate markers of clinical periodontal status

BACKGROUND

This study addresses whether checkerboard assessments of serum IgG antibodies to oral bacteria may serve as surrogate markers of clinical periodontal status in epidemiologic studies.

METHOD

The analysis involved data from 205 subjects, 132 periodontitis patients and 73 periodontally-intact controls, from whom full-mouth clinical periodontal data and serum IgG titers against 19 periodontal bacterial species were available.

RESULTS

A logistic regression model involving titers against 6 species (Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Eubacterium nodatum, Eikenella corrodens, Capnocytophaga ochracea and Actinomyces naeslundii genospecies 2) classified correctly 74.5% of the subjects examined, with 84% sensitivity, 57.5% specificity, 78% positive predictive value and 66.7% negative predictive value.

CONCLUSIONS

Checkerboard serology may be useful in providing surrogate markers for clinical periodontal status when such data are not readily available and, thus may serve as a valuable complement in the armamentarium of epidemiologic tools suited for the study of periodontal diseases.

Identification and antimicrobial susceptibility of enterococci isolated from the root canal

Enterococci are occurring in opportunistic infections involving the oral cavity. This study has identified enterococcal species in 29 endodontic infections undergoing treatment with Ca (OH)2 dressings. The in vitro antimicrobial susceptibility of 29 isolated enterococcal strains was determined. Enterococcus faecalis was speciated for 26 isolates and Enterococcus faecium for three isolates. In vitro antimicrobial susceptibility testing revealed enterococcal isolates resistant to benzylpenicillin, ampicillin, clindamycin, metronidazole and tetracycline but sensitive to erythromycin and vancomycin. Due to low sensitivity to antimicrobial agents, enterococci may be selected in root canals undergoing standard endodontic treatment and significantly contribute to endodontic treatment failures.

Adherence of Bacteroides forsythus to host cells

The adherence characteristics of Bacteroides forsythus to host cells, was examined. Four laboratory strains and twelve clinical isolates of B. forsythus were used. All strains demonstrated different haemagglutination activities. The haemagglutination of B. forsythus was inhibited strongly by amino acids such as L-arginine, L-histidine, L-lysine and L-alanine. The adherence to polymorphonuclear leucocytes (PMNL) was weak except for B. forsythus ATCC 43037 and OMZ 408. The adherence of these strains was inhibited by L-histidine and L-arginine, and was facilitated by trypsin (0.1 mg/ml) treatment of polymorphonucleocytes. B. forsythus strains showed varied adherence to fibroblasts. It is suggested that the adherence of B. forsythus to host cells is mediated by a factor which is sensitive against some amino acids, and altered by trypsin-like enzymes.

"Checkerboard" assessments of periodontal microbiota and serum antibody responses: a case-control study

BACKGROUND

We explored the association between subgingival microbial profiles and serum IgG responses to periodontal microbiota in relation to clinical periodontal status.

METHODS

One hundred thirty-one (131) periodontitis patients aged 29 to 74 years (mean 51.8) were age- and gender-matched with 74 periodontally intact controls (range 26 to 77, mean 49.3). Smoking habits and health history were recorded and assessments of plaque, bleeding on probing, probing depth, and attachment level were performed at 6 sites per tooth on all present teeth, excluding third molars. Subgingival plaque samples were obtained from each tooth in one upper and one lower quadrant (maximum 14 samples/subject; 2,440 samples total) and analyzed with respect to 19 species by means of whole genomic DNA probes. Serum IgG antibodies against the same 19 species were assessed by an immunoassay.

RESULTS

Cases displayed an average of 22.7 teeth, 20.3 sites with probing depth > or =6 mm, and 18.9 sites with attachment loss > or =6 mm. Corresponding figures for controls were 27.1, 0.1, and 1.0, respectively. Heavy smoking was 3 times more frequent among cases than controls (32.1% versus 9.6%). Higher levels of Porphyromonas gingivalis, Porphyromonas endodontalis, Prevotella intermedia, Prevotella nigrescens, Prevotella melaninogenica, Bacteroides forsythus, Fusobacterium nucleatum, Treponema denticola, Eubacterium nodatum, Peptostreptococcus micros, and Campylobacter rectus were found in cases and higher levels of Eikenella corrodens, Veillonella parvula, and Actinomyces naeslundii in controls. Cases displayed higher IgG levels against P. gingivalis and Actinobacillus actinomycetemcomitans, while controls displayed higher levels against F. nucleatum, T. denticola, E. nodatum, and Capnocytophaga ochracea. Positive correlations between bacterial colonization and antibody responses were identified for 9 species in controls. In cases, however, statistically significant correlations were observed for only 3 species out of which only one was positive (V. parvula). Both bacterial levels and antibody responses declined in ages over 55 years. A logistic regression employing selected elements of bacterial colonization and antibody responses as independent variables resulted in 81.1% correct diagnosis, with sensitivity of 83.1%, specificity of 77.8%, positive predictability of 86%, and negative predictability of 73.7%. Smoking did not reach statistical significance in this model.

CONCLUSION

A combined microbial colonization/antibody response profile can effectively discriminate between periodontitis patients and periodontally intact controls.

The diagnostic accuracy of microbiologic root canal sampling and the influence of antimicrobial dressings

The routine approach to endodontic treatment of teeth with apical periodontitis often involves an interappointment dressing with calcium hydroxide. However, investigations have demonstrated a negative influence of calcium hydroxide on the accuracy of microbiological root canal sampling (MRS). The aim of the present study was to investigate whether the use of a fluid dressing like 5% iodine potassium iodide (IPI) would increase the accuracy of MRS. Following instrumentation of 50 teeth with radiographically verified apical periodontitis the root canals received IPI as an intracanal dressing. One week after closure canals were sampled, "test sample" (TS), and then left filled with sampling fluid and temporarily scaled. Seven days later a "gold standard" (GS) sample was obtained. Bacteria were recovered in 22 teeth (44%) in TS as well as in GS. Fifteen teeth (30%) were positive for growth in both samples. Using the detection level "very sparse growth" of microbes the sensitivity and specificity of MRS reached 68% and 75%, respectively. In an earlier study, following the same experimental protocol, but with calcium hydroxide as intracanal dressing, the corresponding values were 33% and 81%. In 25% of these cases bacteria persisted in the canals. As compared to calcium hydroxide, the use of IPI resulted in improved test accuracy, but loss of antibacterial capacity. Conclusively, intracanal dressings seem to vary in their influence on the microbiologic test performance as well as in their antibacterial efficacy. In a clinical situation the choice of interappointment dressing should include consideration of these potentially conflicting properties.

The antimicrobial effect of calcium hydroxide in root canals pretreated with 5% iodine potassium iodide

Calcium hydroxide (CH) is often used as a routine interappointment dressing during the endodontic treatment of teeth with apical periodontitis. However, it fails to consistently produce sterile root canals. The present study was set up to find out whether an antimicrobial strategy including the use of CH could be made more effective if: 1) canals were pretreated with 5% iodine potassium iodide (IPI), and 2) the dressing period was extended up to 2 months. Fifty human teeth, with radiographically verified apical periodontitis, were microbiologically sampled. After chemomechanical preparation the canals were pretreated with IPI for 3-7 days. Teeth where microorganisms persisted were then treated with CH for 2 months. Following instrumentation and dressing with IPI, 43 bacterial strains were recovered in 22 of the teeth. Samples obtained after the CH dressing period disclosed growth of 13 facultative and two strict anaerobic strains in 10 teeth. Enterococcus faecalis was identified in two specimens. In conclusion, the present study gave no evidence for an increased antimicrobial effect of CH if it was left for longer periods in the root canal. Although pretreatment with IPI from a quantitative point of view did not seem to add antimicrobial power, it might reduce the frequency of persisting strains of E. faecalis.

Microbial findings at failing implants

The aim of this study was to evaluate qualitative differences in the subgingival microbiota at titanium implants, ad modum Brånemark, demonstrating clinical and radiographic signs of loss of supporting tissues (peri-implantitis) as compared to implants surrounded by healthy tissues. A total of 37 patients demonstrating 1 or more implants with bone loss > or = 3 threads, bleeding on probing and/or suppuration and 51 patients with clinically healthy mucosa and no bone loss were recruited for the study. In each patient subgingival bacterial samples were obtained using paper-points, and subjected to microbiological analysis by culture. The two types of clinical conditions showed distinct bacterial profiles. For implants with peri-implantitis putative periodontal pathogens, such as Porphyromonas gingivalis, Prevotella intermedia/Prevotella nigrescens and Actinobacillus actinomycetemcomitans, were found in 60% of the cases and microorganisms primarily not associated with periodontitis, such as Staphylococcus spp., enterics and Candida spp., were found in 55% of the peri-imaplant lesions. In contrast, implants surrounded by healthy tissue demonstrated a microbiota associated with periodontal health. The results indicate that the microbiota of the healthy peri-implant sulci is similar to that from corresponding conditions around teeth. However, in peri-implant areas staphylococci, enterics and yeasts were found almost as frequently as periopathogens indicating differences as compared to the microbiota around periodontitis affected teeth. A microbiological diagnosis may therefore be of guidance for the choice of antimicrobial treatment in patients with peri-implant infection.

The association of hyperlipidemia with retinopathy in diabetic patients aged 15-50 years in the county of Umeå

PURPOSE

To study possible associations between serum lipid levels and degree of retinopathy in a population-based study on a specific age-group of patients with diabetes mellitus in the county of Umeå, Sweden.

METHODS

All patients with diabetes mellitus aged 15-50 years living in the county of Umeå were invited to the study. The participating subjects had a standard clinical examination and an eye examination performed. Seven-field stereoscopic photographs were taken of each eye, and the photos were sent to Grading Center, Hammersmith Hospital, London, U.K. for grading of the retinopathy. Blood samples were drawn for analysis of lipoprotein(a), high density lipoprotein (HDL) cholesterol, cholesterol and triglycerides. Univariate and multivariate statistical analyses were performed.

RESULTS

In the present study only patients with type 1 diabetes mellitus were included, and 285 of the invited 308 diabetic subjects (93%) took part. When univariate analysis was applied we found statistically significant associations between higher lipoprotein(a) levels, higher triglyceride levels, higher cholesterol levels, lower HDL cholesterol/total cholesterol ratios and increasing severeness of retinopathy. However, in the multivariate analysis triglyceride levels lost their importance while all other significant associations were still present.

CONCLUSION

Associations were found between higher levels of serum total cholesterol, declining ratios of high density lipoprotein (HDL) cholesterol/total cholesterol, higher levels of serum lipoprotein(a) and more severe retinopathy in diabetes mellitus type 1. No such association was found between serum triglycerides and degree of retinopathy.