[Not Available]. / Bedeutung der Hepatitis C-Virusinfektion in der zahnärztlichen Praxis.

This article gives a short overview about the epidemiology, transmission, clinical appearance, testing and therapy of hepatitis C virus infection and its importance in the healthcare setting. Standard infection control measures in dental practice remain essential for the prevention of HCV transmission.

Caries experience in 7-, 12-, and 15-year-old schoolchildren in the canton of Basel-Landschaft, Switzerland, from 1992 to 2011.

OBJECTIVES: To investigate the changes in caries experience and prevalence among schoolchildren of the canton of Basel-Landschaft, Switzerland, over the course of 20 years. METHODS: A random sample of either schoolchildren aged 7, 12, and 15 years (in 1992) or aged 12 and 15 years (in 1997) or their respective school classes (2001, 2006 and 2011) was selected so that approximately 10% of schoolchildren could be examined. The children's dmft and DMFT scores were determined according to the WHO methodology and analyzed using cluster-adjusted ordinary multiple linear regression modeling. RESULTS: For all age groups, the respective dmft/DMFT values decreased steadily from 1992 to 2006 but increased again in 2011. However, the observed differences were not statistically significant over the examination years from 2001 to 2011. Schoolchildren with a migrant background had approximately two- to threefold higher dmft/DMFT values. CONCLUSIONS: In the years from 1992 to 2001, a steady decline in caries was observed in all age groups of schoolchildren examined in the canton of Basel-Landschaft. However, in the subsequent 10 years, this decline has leveled off. The mean dmft/DMFT values are comparable to those in other parts of Switzerland. Migrants are a caries-risk group; the mean dmft/DMFT values were higher in schoolchildren with a migrant background than in the comparable Swiss children.

Effects of Er:YAG laser on bacteria associated with titanium surfaces and cellular response in vitro.

This in vitro study examined (a) the anti-bacterial efficacy of a pulsed erbium-doped yttrium aluminum garnet (Er:YAG) laser applied to Streptococcus sanguinis or Porphyromonas gingivalis adhered to either polished or microstructured titanium implant surfaces, (b) the response of osteoblast-like cells and (c) adhesion of oral bacteria to titanium surfaces after laser irradiation. Thereto, (a) bacteria adhered to titanium disks were irradiated with a pulsed Er:YAG laser (λ = 2,940 nm) at two different power settings: a lower mode (12.74 J/cm(2) calculated energy density) and a higher mode (63.69 J/cm(2)). (b) After laser irradiation with both settings of sterile titanium, disks were seeded with 10(4) MG-63 cells/cm(2). Adhesion and proliferation were determined after 1, 4, and 24 h by fluorescence microscopy and scanning electron microscopy. (c) Bacterial adhesion was also studied on irradiated (test) and non-irradiated (control) surfaces. Adhered P. gingivalis were effectively killed, even at the lower laser setting, independent of the material's surface. S. sanguinis cells adhered were effectively killed only at the higher setting of 63.69 J/cm(2). Laser irradiation of titanium surfaces had no significant effects on (b) adhesion or proliferation of osteoblast-like MG-63 cells or (c) adhesion of both oral bacterial species in comparison to untreated surfaces. An effective decontamination of polished and rough titanium implant surfaces with a Er:YAG laser could only be achieved with a fluence of 63.69 J/cm(2). Even though this setting may lead to certain surface alterations, no significant adverse effect on subsequent colonization and proliferation of MG-63 cells or increased bacterial adhesion was found in comparison to untreated control surfaces.

Decreased susceptibility of Neisseria gonorrhoeae isolates from Switzerland to Cefixime and Ceftriaxone: antimicrobial susceptibility data from 1990 and 2000 to 2012.

BACKGROUND: Neisseria gonorrhoeae can rapidly develop resistance to antimicrobial agents. Over the last years, decreased gonococcal susceptibility to third-generation cephalosporins, especially cefixime, emerged worldwide. Therefore, current international guidelines recommend dual therapy for gonorrhoea with ceftriaxone plus either azithromycin or doxycycline. Gonococcal susceptibility data in Switzerland are sparse. METHODS: We investigated the prevalence of antibiotic susceptibility of N. gonorrhoeae in specimens collected between 1990 and 2012 at the University of Zurich, Switzerland. Minimum inhibitory concentrations (MICs) for cefixime, ceftriaxone, ciprofloxacin, and penicillin were determined by Etests. The European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints were used to define reduced susceptibility. RESULTS: A total of 320 isolates were tested. Between 1990 and 2006 all tested samples were susceptible to both cephalosporins. Subsequently, the prevalence of elevated MICs for cefixime increased to 10.4% (2007/2008), 11.5% (2009/2010), and 11.4% (2011/2012); and for ceftriaxone to 2.4% (2007/2008), 4.7% (2009/2010), and 0% (2011/2012), respectively. The prevalence of resistance to ciprofloxacin (72.7%) and penicillin (22.7%) was high in 2011/2012. CONCLUSIONS: Decreasing susceptibility of N. gonorrhoeae to third-generation cephalosporins in Switzerland supports treatment recommendations with ceftriaxone plus azithromycin or doxycycline. Health-care providers need to be aware of possible treatment failures with cephalosporins. Continued surveillance of gonococcal antimicrobial resistance is essential.

Prescription of antibiotics in the dental practice: a survey of dentists in Switzerland.

In dentistry, antibiotics are prescribed both for prophylactic and therapeutic purposes. Their unwarranted use, however, may lead to the selection of resistant microorganisms. The aim of this study was to evaluate the indications and the extent of antibiotic prescription by dentists in Switzerland. A questionnaire was sent to 800 dentists during the winter of 2008/2009. Responses to the questionnaire were received from 20% of them. Many respondents indicated that they tried to prescribe antibiotics in a selective and cautious manner. Nevertheless, uncertainties existed regarding the indications. For example, the frequency of prescribing an antibiotic when it was not absolutely necessary was related to the respondents' uncertainty regarding the correct diagnosis and therapy. Not surprisingly, two-thirds of the respondents would prefer to have precise guidelines for the use of these drugs.

Influence of gaseous ozone in peri-implantitis: bactericidal efficacy and cellular response. An in vitro study using titanium and zirconia.

Dental implants are prone to bacterial colonization which may result in bone destruction and implant loss. Treatments of peri-implant disease aim to reduce bacterial adherence while leaving the implant surface intact for attachment of bone-regenerating host cells. The aims of this study were to investigate the antimicrobial efficacy of gaseous ozone on bacteria adhered to various titanium and zirconia surfaces and to evaluate adhesion of osteoblast-like MG-63 cells to ozone-treated surfaces. Saliva-coated titanium (SLA and polished) and zirconia (acid etched and polished) disks served as substrates for the adherence of Streptococcus sanguinis DSM20068 and Porphyromonas gingivalis ATCC33277. The test specimens were treated with gaseous ozone (140 ppm; 33 mL/s) for 6 and 24 s. Bacteria were resuspended using ultrasonication, serially diluted and cultured. MG-63 cell adhesion was analyzed with reference to cell attachment, morphology, spreading, and proliferation. Surface topography as well as cell morphology of the test specimens were inspected by SEM. The highest bacterial adherence was found on titanium SLA whereas the other surfaces revealed 50-75% less adherent bacteria. P. gingivalis was eliminated by ozone from all surfaces within 24 s to below the detection limit (≥99.94% reduction). S. sanguinis was more resistant and showed the highest reduction on zirconia substrates (>90% reduction). Ozone treatment did not affect the surface structures of the test specimens and did not influence osteoblastic cell adhesion and proliferation negatively. Titanium (polished) and zirconia (acid etched and polished) had a lower colonization potential and may be suitable material for implant abutments. Gaseous ozone showed selective efficacy to reduce adherent bacteria on titanium and zirconia without affecting adhesion and proliferation of osteoblastic cells. This in vitro study may provide a solid basis for clinical studies on gaseous ozone treatment of peri-implantitis and revealed an essential base for sufficient tissue regeneration.

Prevalence of enamel fluorosis in 12-year-olds in two Swiss cantons.

The neighbouring cantons Basel-Stadt and Basel-Landschaft had introduced different fluoridation schemes for caries prevention: Basel-Stadt provided drinking water fluoridated at 0.8-1 ppm F since 1962, while Basel-Landschaft introduced fluoridated domestic salt (250 ppm F since 1983). Representative samples of 12-year-old schoolchildren (6th-graders) were studied to evaluate the prevalence of (I) dental fluorosis (FOP) using the Thylstrup-Fejerskov (TF) index, (II) non fluoride-associated enamel opacities (non-FOP), and (III) hypoplasia of the incisors. Standardised frontal colour photographs were taken and assessed by four examiners after projection. Of 373 schoolchildren studied in 1999 in Basel-Stadt 119 (31.9%) showed fluoride-associated enamel opacities, i. e. 66 (17.7%) a very mild form (TF score 1), 47 (12.6%) a mild form (TF score 2), five scored TF3 and one TF5. In addition, non-FOP were diagnosed in 115 (30.8%) and hypoplasia in 47 (12.6%) children. Among the 448 children evaluated in 2001 in Basel-Landschaft 143 (31.9%) showed FOP, namely 74 (16.5%) scored TF1, 54 (12.2%) scored TF2, 12 (2.7%) scored TF3, and three (0.7%) scored TF5. Non-FOP were found among 93 (20.8%) and hypoplasia among 56 (12.5%) children. Thus, in spite of different fluoridation schemes in the two cantons, the prevalences of FOP were identical. Most fluoride-associated enamel opacities were mild or very mild. They did not represent an aesthetic problem and certainly not a public health concern.

Bactericidal effects of different laser systems on bacteria adhered to dental implant surfaces: an in vitro study comparing zirconia with titanium.

OBJECTIVES: The purpose of this study was to examine in vitro the anti-bacterial efficacy of two different laser systems (CO(2) and diode) applied to Streptococcus sanguinis or Porphyromonas gingivalis cells in suspensions or adhered to zirconia or titanium dental implant materials, with two different surfaces each. MATERIALS AND METHODS: Bacteria were irradiated at two different power settings with either a CO(2) (lambda=10,600 nm) or a diode laser (lambda=810 nm). The lower mode is used clinically (for CO(2) 100 J/cm(2), diode 50 J/cm(2)) and the higher may alter the materials' surface (for CO(2) 1200 J/cm(2), diode 150 J/cm(2)). After irradiation, the number of viable bacteria was determined by culture. RESULTS: Planktonic cells of both species were more resistant to the laser irradiations than bacteria that adhered to surfaces. Adhered P. gingivalis were effectively killed at both wavelengths lambda=10,600 and 810 nm even at the lower settings, independent of the material. S. sanguinis cells that adhered to either zirconia surface were effectively killed by the CO(2) laser at the lower setting of 100 J/cm(2). However, the higher settings of both lasers were needed to reduce S. sanguinis that adhered to titanium surfaces. The CO(2) laser at the lower setting and the diode laser at the higher setting effectively reduced the viability of S. sanguinis or P. gingivalis that adhered to zirconia surfaces. CONCLUSIONS: Under irradiation conditions known not to alter zirconia implant surfaces in vitro, both CO(2) laser (100 J/cm(2)) and the diode laser (150 J/cm(2)) effectively reduced the viability of adhered S. sanguinis or P. gingivalis.

Methicillin-resistant Staphylococcus aureus (MRSA) among dental patients: a problem for infection control in dentistry?

We assessed the frequency of carriers of methicillin-resistant Staphylococcus aureus (MRSA) among 500 dental patients of a university clinic. From each participant, two specimens were taken from the anterior nares and the pharynx and analysed by culture. The participants completed a questionnaire on possible risk factors of MRSA infection. Two hundred ten individuals carried S. aureus, 90 in the nares only, 51 in the throat only and 69 in nares and throat. Isolates of 208 patients were methicillin-sensitive; two isolates were methicillin-resistant, both carried in the throat exclusively. In conclusion, the frequency of nasal and/or throat carriers of MRSA among dental patients was low and suggests few opportunities of exposure in the dental clinic assessed.

Comparison of the immediate effects of gaseous ozone and chlorhexidine gel on bacteria in cavitated carious lesions in children in vivo.

Clinical application of ozone gas has been shown to arrest the progression of dentinal caries in children. In this study, we compare the immediate effects of gaseous ozone and chlorhexidine gel on bacteria in cavitated carious lesions in children. Forty children, each with at least two open occlusal carious lesions, were enrolled in the study. Two teeth were chosen randomly. In one lesion, overlying soft biological material was removed, whilst the other lesion was not excavated. Cavities were rinsed with sterile water and dried with air. A standardised sample was taken from the mesial part of each lesion. Then, gaseous ozone (HealOzone) or 1% chlorhexidine gel (Corsodyl) was applied for 30 s on both lesions of 20 children each, and a second sample was taken from the distal part of each lesion. The anaerobic microbiota was cultivated; the number of colony forming units was calculated per milligram sample. The two-sided paired t test showed no significant (P > 0.05) differences in the reduction of total bacterial counts per milligram comparing samples before and after ozone or chlorhexidine application. The tests also showed no statistically significant difference whether the superficial decayed dentine had been removed before ozone or with chlorhexidine treatment or not. It can be concluded that gaseous ozone or chlorhexidine gel application for 30 s to deep occlusal carious cavities had no significant immediate antimicrobial effects whether the superficial decayed layers dentine were removed or not.

Antimicrobial susceptibility of periodontopathogenic bacteria.

OBJECTIVES: The aim of this study was to evaluate the resistance profiles of Aggregatibacter (Actinobacillus) actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia/Prevotella nigrescens and to detect possible changes in antibiotic resistance over the time period of 1991-2005. METHODS: A. actinomycetemcomitans (125 strains), P. gingivalis (152 strains) and P. intermedia/P. nigrescens (326 strains) isolated during the years 1991-2005 were tested for their susceptibility to amoxicillin/clavulanic acid, clindamycin, metronidazole, phenoxymethylpenicillin and tetracycline using the Etest. RESULTS: No antibiotic resistance was detected in P. gingivalis, whereas a few isolates of P. intermedia were not susceptible to clindamycin (0.9%), phenoxymethylpenicillin (13.5%) or tetracycline (12.6%). Amoxicillin/clavulanic acid, tetracycline and metronidazole were the most effective antibiotics against A. actinomycetemcomitans with 0%, 0.8% and 20.8% non-susceptible isolates, respectively. However, 88% of the A. actinomycetemcomitans isolates were non-susceptible to phenoxymethylpenicillin and 88% to clindamycin. When strains isolated in the years 1991-94 were compared with those isolated in the years 2001-04, there was no statistically significant difference in the percentage of A. actinomycetemcomitans strains non-susceptible to clindamycin, metronidazole or phenoxymethylpenicillin, or in the percentage of P. intermedia strains non-susceptible to phenoxymethylpenicillin or tetracycline (P > 0.4 each). CONCLUSIONS: Increasing antibiotic resistances in periodontopathogenic bacteria are not yet a problem in the Northern part of Switzerland.

Adhesion of Streptococcus sanguinis to glass surfaces measured by isothermal microcalorimetry (IMC).

Bacterial adhesion is the first step in the development of the oral biofilm, called dental plaque. Plaque is the cause of caries, periodontal diseases, and periimplantitis. Investigations of dental plaque, including bacterial adhesion, employ various in vivo and in vitro models using microscopic methods. Microcalorimetry offers another direct approach. The model organism Streptococcus sanguinis is one of the first colonizers adhering to the saliva-coated human tooth surfaces or dental materials within minutes after tooth cleaning. TAM III thermostats, equipped with microcalorimeters, were used for isothermal microcalorimetric (IMC) measurements of heat production as a function of time, expressed by power-time (p-t) curves. Continuous measurements of heat production of growing S. sanguinis cells showed their overall metabolic activity and were highly reproducible. For the adhesion experiments the bacteria were allowed to adhere to different amounts of glass beads. Growing S. sanguinis cells produced a characteristic p-t curve with a maximum of 500 microW at 4.5 h when reaching 10(9) cells ml(-1). The same number of stationary S. sanguinis cells, suspended in PBS produced only approximately 30 microW at 0.5 h due to adhesion. But the amount of heat increased with available glass surface area, indicating that a portion of the heat of adhesion was measured. Similar results were obtained with stationary S. sanguinis cells suspended in human saliva. This study shows that microcalorimetric evaluation of initial bacterial adhesion is indeed possible and may become a rapid, reproducible screening method to study adhesion of different bacteria to different dental materials or to modified surfaces.

Antimicrobial activity of Mahonia aquifolium and two of its alkaloids against oral bacteria.

Extracts or alkaloids isolated from Mahonia aquifolium exhibit antimicrobial activity against Gram-positive and Gram-negative bacteria, fungi, and protozoa. In this study the bacteriostatic and bacteriocidal activities of a M. aquifolium extract and two of its major alkaloids, berberine chloride and oxyacanthine sulphate, were tested in vitro against nine different oral bacteria. Minimum inhibitory concentrations were in the range from < or = 0.0031% to 0.1993% for the M. aquifolium extract, from 0.002% to > 0.125% for berberine chloride, and from 0.0156% to > 0.0625% for oxyacanthine sulphate. The values for the minimum bactericidal concentrations were in the same range, indicating that the test substances most probably acted in a bactericidal manner. The most susceptible bacterium against all three test substances was Porphyromonas gingivalis.

[Early detection and prevention of oral precancer. An enquiry among dentists in Switzerland]. / Früherkennung und Prävention von Präkanzerosen der Mundhöhle. Eine Umfrage unter Zahnärzten in der Schweiz.

Squamous cell carcinoma ranks eighth among the most common tumors worldwide. In many cases, these tumors develop from a preliminary phase (precancerosis). For different reasons, these preinitial carcinomas are recognised too late or not at all. The aim of this study was to find out about the dentists' state of knowledge, their management of these tumors and their readiness for a prevention campaign among Swiss dentists. 800 questionnaires were mailed or handed out to dentists nationwide. 22% of the questionnaires were returned. 64% of the dentists stated to be highly motivated for further education and 81% were willing to participate in a prevention campaign. 94% of the dentists examine the oral mucosa inclusive the (palatine) tonsil bed at least once a year, but only 15% of the participating dentists discuss the risk factors like alcohol or tobacco consumption with their patients. The most common factors which inhibit prevention in daily routine are the patients' refusal, a lack of education in that field, absence of information flyers and lack of time. A primary and secondary prevention program would be preferable to achieve a decrease in the incidence rate of squamous cell carcinoma.

Adhesion of Streptococcus sanguinis to dental implant and restorative materials in vitro.

Bacterial adhesion to tooth surfaces or dental materials starts immediately upon exposure to the oral environment. The aim of this study, therefore, was to compare the adhesion of Streptococcus sanguinis to saliva-coated human enamel and dental materials - during a one-hour period - using an in vitro flow chamber system which mimicked the oral cavity. After fluorescent staining, the number of adhered cells and their vitality were recorded. The dental materials used were: titanium (Rematitan M), gold (Neocast 3), ceramic (Vita Omega 900), and composite (Tetric Ceram). The number of adherent bacterial cells was higher on titanium, gold, and ceramic surfaces and lower on composite as compared to enamel. As for the percentage of adherent vital cells, it was higher on enamel than on the restorative materials tested. These results suggested that variations in the number and vitality of the adherent pioneer oral bacteria, S. sanguinis, in the in vitro system depended on the surface characteristics of the substratum and the acquired salivary pellicle. The in vitro adhesion model used herein provided a simple and reproducible approach to investigate the impact of surface-modified dental materials on bacterial adhesion and vitality.

Clinical effectiveness of two different toothbrushes in the elderly.

Proper tooth brushing is the simplest way to maintain oral health. Still, it can cause considerable manipulative difficulties among parts of the population, like the elderly. The aim of this study was to evaluate a tool that could make tooth-brushing more effective and easier for this age group. Therefore, in a population of 34 elderly people aged 65 and over, we compared the plaque-removing ability of the Superbrush, a three-headed toothbrush, with the Elmex interX and the toothbrush normally used. A balanced cross-over design was chosen and the study was operator-blind. Two indices were used to measure the plaque-removing abilities of the toothbrushes, the OHI (Quigley-Hein plaque index) and the API (proximal plaque index). Professional tooth cleaning was performed to obtain a plaque-free condition at the beginning of the study as well as before switching to a new toothbrush. After one week of using each toothbrush, the OHI and API were determined to assess the oral hygiene status of each participant. The overall plaque removal was similar for the Superbrush, the Elmex interX and the patients' own toothbrushes. However, at the oral surfaces of the teeth, the Superbrush was significantly more effective than the other toothbrushes. No or only small differences were found for other surfaces (posterior and front teeth and facial surfaces).

Oral health risks associated with HLA-types of patients undergoing hematopoietic stem cell transplantation.

AIM: Dental caries, gingivitis and periodontitis are frequent long-term complications after hematopoietic stem cell transplantation (HSCT). Not all patients are affected equally. As HLA-genotypes are associated with many functions of the immune system we made use of our long-standing oral health program in HSCT recipients to compare oral health data with recipient HLA-antigens. PATIENTS AND METHODS: This study includes 267 patients evaluated prior to a planned HSCT at our institution between March 1987 and March 2002. Standardized oral examinations were undertaken at fixed time points: pre-HSCT and at 6 and 12 months post-HSCT. Evaluation included loss of radiologic attachment level, decayed, missing, filled teeth (DMFT) index, and salivary flow rate. For 241 patients (120 males, 121 females) baseline values of these parameters were compared with recipient HLA-A, -B, -C and -DR-antigens. RESULTS: Significant correlations were found between increased DMFT and HLA-A32 (P = 0.05), -B5 (0.04), and -DR2 (0.05) as well as decreased DMFT with HLA-B35 (0.02) and -C4 (0.04). Significant associations were also found between certain HLA-antigens and loss of radiologic periodontal attachment level [HLA-A1 (<0.01), -C7 (0.04), and -B60 (0.05)], and saliva flow rate [HLA-A30 (0.02)]. CONCLUSIONS: These data suggest that there may be associations between pretransplant caries, other oral parameters and HLA in patients at HSCT. Confirmatory studies concerning the associations of certain HLA-antigens with caries and periodontal diseases will be needed.

Fluoride excretion of adults living in border regions with either water or salt fluoridation.

The canton of Basel-Stadt was the only canton in Switzerland which introduced drinking water fluoridation (DWF) at 1 ppm (mg/l). All other cantons have relied on fluoridated domestic salt at 250 ppm F as the main vehicle for basic fluoride exposure. It has been suggested that persons living and working in the DWF areas or persons commuting to the DWF areas may be exposed to higher than optimal doses of fluoride. The objective of this present study was to determine the urinary fluoride excretion of adults living and or working in neighboring areas of either salt or water fluoridation. In this study, 24-hour urine was collected from 69 healthy subjects and tested for fluoride concentration. The mean fluoride concentration for all participants was 0.55 +/- 0.25 ppm (mg/l) ranging from 1.14 to 0.09 ppm. The mean fluoride excretion was 0.95 +/- 0.47 mg F/d ranging from 0.18 to 2.12 mg F/d. The 33 subjects living in a DWF region showed a mean urine fluoride concentration of 0.64 +/- 0.24 ppm (mg/l) and a mean fluoride excretion of 1.14 +/- 0.48 mg F/d. Those 36 subjects living in a region without DWF showed a mean urine fluoride concentration of 0.47 +/- 0.24 ppm (mg/l) and a mean fluoride excretion of 0.78 +/- 0.40 mg F/d. A significant difference between the two means of the groups living in regions with or without DWF was detected when the Mann-Whitney statistical test was applied (p < 0.005). The combined intake of fluoridated drinking water and fluoridated table salt in the sub-group of 11 subjects who commuted showed an overall increase in fluoride urine concentration. The measured values, however, were not significantly different from the other sub-groups.

[Milk fluoridation--where are we today?]. / Milchfluoridierung--wo stehen wir heute?

This review deals with and discusses the history and objectives of milk fluoridation from its early beginnings in Winterthur/Switzerland up to current, WHO-sponsored controlled clinical trials with some 10000 children in several developing and emerging countries as well as in Great Britain. Today the fluoridation of milk in Switzerland does not represent an alternative to the fluoridation of salt and therefore has no practical meaning in this country.

[Critical assessment of microbiological diagnostics in periodontal diseases with special focus on Porphyromonas gingivalis]. / Kritische Beurteilung mikrobiologischer Diagnostik bei marginaler Parodontitis unter besonderer Berüchsichtigung von Porphyomonas gingivalis.

Periodontitis is caused by an opportunistic infection with pathogenic microorganisms of the oral biofilm. In this paper, we discuss the usefulness of microbial diagnostics with respect to the differential diagnosis or the treatment approaches of periodontal diseases. Several diagnostic techniques, based on morphological, enzymatic, cultural, genetic or antigenetic properties have been established to analyze the microbial flora. Among the bacterial species some virulent genotypes of P. gingivalis play an important role in the etiology of periodontitis. Expression of fimbriae or different proteases have been identified as potential virulence factors of this gram negative anaerobic rod. To date a characterization of virulence of specific strains or a correlation between expression of different virulence factors and distinct periodontal conditions, however, is missing. Therefore, the importance of a routine identification of P. gingivalis still needs further evaluation.