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Identifying additional information obtained by X-rays combined with clinical examination concerning primary caries, caries adjacent to restorations and quality of restorations.A total of 240 adult patients, equally distributed in gender and six age-groups, were randomly selected from an original study population of 4,402 subjects (DANHES). Clinical and radiographical registrations on occlusal and approximal surfaces in posterior teeth were categorized into unrestored surfaces (sound/primary caries) and restored surfaces (without/with caries adjacent to restorations). Material and quality of restorations were also recorded. Chi-square and Fisher-exact tests were used for statistical analyses.Of potentially 11,520 surfaces, 3,015 occlusal and 5,112 approximal surfaces were analysed.First-time clinical examination must be supplemented with X-rays to obtain a complete impression of caries status in posterior regions regarding diagnostics of caries, assessment of lesion depth and quality of restorations.

Nú eru næstum tvö ár liðin frá því að nýja kórónuveiran SARS-CoV-2 hóf að breiðast út um allan heim frá Wuhan í Kína og leiddi til heimsfaraldurs kórónuveirunnar (COVID-19). Einkenni COVID-19 geta verið allt frá vægum einkennum í öndunar- og meltingarfærum til alvarlegrar lungnabólgu og jafnvel dauða. Ný stökkbreytt afbrigði sem hafa hugsanlega í för með sér breytingar á klínískum eiginleikum, svo sem smithættu, alvarleika sjúkdóms og virkni bóluefnis, hafa reglulega komið fram. SARS-CoV-2 smitast fyrst og fremst með seyti frá öndunarvegum. Veiran finnst oft í munnvatni smitaðra sjúklinga, hvort sem þeir eru einkennalausir eða ekki. Það hefur valdið verulegum áhyggjum vegna hættu á smiti milli tannlækna og sjúklinga við tannlæknaþjónustu. Því var aðgangur að tannlæknaþjónustu sem ekki var brýn mjög takmarkaður í upphafi heimsfaraldursins. Af því leiðir að uppsöfnuð þörf er á tannlæknaþjónustu og hætta á að tafir verði á meðferð. SARS-CoV-2 veiran getur borist í þekjufrumur í munnholi og munnvatnskirtla. Enn sem komið er eru engar vísbendingar um að SARS-CoV-2 sýking í munnholi hafi verið staðfest með veirugreiningu. Vísbendingar eru um að slök munn- og tannheilsa, einkum tannhaldsbólga, geti gert COVID-19 sýkingu verri. Það getur gerst með þeim hætti að bakteríur í munnholi berist í öndunarveg og valdi þannig samsýkingu, eða vegna altæks bólguástands af völdum tannhaldsbólgu. Þörf er á frekari rannsóknum til að meta hugsanleg áhrif SARS-CoV-2 veirunnar á munnheilsu og almennt heilbrigði. Lykilorð: SARS-CoV-2, COVID-19, munnvatn, munnslímhúð, munnvatnskirtlar, smitvarnir

Teeth are colonized by oral bacteria from saliva containing more than 700 different bacterial species. If removed regularly, the dental biofilm mainly comprises oral streptococci and is regarded as resident microflora. But if left undisturbed, a complex biofilm containing up to 100 bacterial species at a site will build up and may eventually cause development of disease. Depending on local ecological factors, the composition of the dental biofilm may vary considerably. With access to excess carbohydrates, the dental biofilm will be dominated by mainly gram-positive carbohydrate-fermenting bacteria causing demineralization of teeth, dental caries, which may further lead to inflammation and necrosis in the pulp and periapical region, i.e., pulpitis and periapical periodontitis. In supra- and subgingival biofilms, predominantly gram-negative, anaerobic proteolytic bacteria will colonize and cause gingival inflammation and breakdown of supporting periodontal fibers and bone and ultimately tooth loss, i.e., gingivitis, chronic or aggressive periodontitis, and around dental implants, peri-implantitis. Furthermore, bacteria from the dental biofilm may spread to other parts of the body by bacteremia and cause systemic disease. Basically, prevention and treatment of dental biofilm infections are achieved by regular personal and professional removal of the dental biofilm.

Associations of risk factors/indicators with periodontitis may depend on the included case criterion. The objective of the current study is to evaluate differences in outcome by applying five periodontitis case definitions for cross-sectional associations with lifestyle factors among participants of the Danish Health Examination Survey (DANHES).A total of 4,402 adults aged 18 to 96 years from the general health examination of DANHES had a periodontal examination consisting of half-mouth registration at six sites per tooth including probing depth (PD) and clinical attachment level (CAL). Periodontitis was defined according to severe periodontitis, European Workshop of Periodontology (EWP)-specific, meanCAL ≥2.55 mm, CAL-tertile, and PD-CAL definitions. Multivariable logistic regression models fitted the association of age, sex, smoking status, diabetes mellitus, educational level, alcohol consumption, body mass index, physical activity, body fat percentage, waist circumference, triglycerides, total cholesterol, and C-reactive protein with periodontitis.Number of cases captured by the five periodontitis case definitions ranged from 337 (9.2%) to 1,136 (31.0%). A total of 224 participants were defined as periodontitis cases by all five criteria. Analyses on 3,665 participants with complete data revealed statistically significant associations of age and smoking with all periodontitis case definitions and of male sex with severe periodontitis and EWP-specific definitions. Educational level (two lowest groups) was related to three periodontitis criteria. Among obesity and hyperlipidemia measures no factors were related to periodontitis.Regression analyses showed little difference in odds ratio across the five periodontitis case definitions; however, the level of significance did show some variation.

ObjectiveTo investigate whether intakes of Ca, vitamin D, casein and whey are associated with periodontitis and to investigate the possibility of interactions between them.DesignCross-sectional study. An Internet-based, 267-item FFQ was used to assess dietary intake. Intakes of casein (32·0 g/d), whey proteins (9·6 g/d) and vitamin D (5·8 μg/d) were classified as withinv.above the 50th percentile. Ca intake was classified as withinv.below age-specific recommendations. Severe periodontitis was defined as having ≥2 inter-proximal sites with clinical attachment loss ≥6 mm (not on the same tooth) and ≥1 inter-proximal site with pocket depth ≥5 mm. Since vitamin D influences Ca absorption, models were stratified by lower and higher (v. ≥5·8 µg/d) vitamin D intake.SettingDanish Health Examination Survey (DANHES) 2007–2008.SubjectsAdult participants (n3287) in the oral health study of DANHES 2007–2008.ResultsIntakes of Ca within recommendations (OR=0·76; 95 % CI 0·58, 0·99), whey ≥9·6 g/d (OR=0·75; 95 % CI 0·58, 0·97) and casein ≥32 g/d (OR=0·75 95 % CI 0·58, 0·97) were associated with lower likelihood of severe periodontitis after adjustment for age, gender, education, smoking, sucrose intake, alcohol consumption, number of teeth, daily brushing, regular visits to the dentist and chronic illness, irrespective of vitamin D intake levels. Intake of vitamin D alone was not associated severe with periodontitis.ConclusionsIntakes of Ca, casein and whey protein were inversely associated with periodontitis. Consumption of foods rich in Ca, casein and whey (e.g. dairy foods) should be promoted, as they may contribute to the prevention of periodontitis. Further longitudinal studies are required to confirm these associations.

The purpose of the study was to examine the susceptibility of two different small-sized spirochete morphotypes from subgingival plaque to eight antibiotics and chlorhexidine. MIC-values were determined by a broth dilution method and related to achievable antibiotic tissue- and blood concentrations. The spirochetes were characterized as susceptible, moderate susceptible, and resistant to the different antibiotics. The MICs of tetracycline hydrochloride, doxycycline, penicillin G, and chlorhexidine were all considerably lower for spirochete strains with a 2:4:2 endoflagella system (two endoflagella from each cell-end) than for strains with a 1:2:1 endoflagella system (one endoflagellum from each cell-end). No differences were observed for the remaining antibiotics. Spirochetes containing one endoflagellum from each cell-end were found to be susceptible to metronidazole and doxycycline, susceptible to moderate susceptible to tetracycline hydrochloride, moderate susceptible to penicillin G, and resistant to the remaining antibiotics. Spirochetes containing two endoflagella from each cell-end were susceptible to doxycycline, tetracycline hydrochloride, and metronidazole. Susceptible to moderate susceptible to penicillin G. These spirochetes were resistant to the remaining agents. The significance of these observations is discussed in relation to obtainable gingival crevicular fluid concentrations and treatment of marginal periodontitis.

The purpose of the present investigation was to establish a biochemical characterization of oral spirochetes containing one endoflagellum from each cell-end. Nine spirochete strains were isolated from subgingival plaque with pocket depth greater than 6 mm. The following metabolic capabilities were examined: fermentation of 16 different carbohydrates, hydrolysis of urea, gelatin and esculin, and production of indol and H2S. Furthermore activities of the following categories of enzymes were examined: proteases, peptidases, lipases, glycosidases, phosphatases, and mucopolysaccharadases. The tests and analyses were routinely carried out with cultures in the early stationary phase of growth. Of the examined metabolic capabilities eleven of the 21 characters were identical for all strains. Only the fermentation of some of the carbohydrates varied between the strains. All strains were identical regarding the examined enzymes. The following enzyme activities were found: acid and alkaline phosphatase, C-4 (butyrate)-, and C-8 (caprylate)-lipases, peptidases, hyaluronidase, and chondroitinsulfatase. The findings are compared with earlier observations for the same spirochete morphotype and with small-sized spirochetes containing two endoflagella from each cell-end.

To evaluate the in vitro abilities of probiotic bacteria derived from consumer products to coaggregate with caries-associated mutans streptococci.Six lactobacillus strains (L. acidophilus (CCUG 5917), L. plantarum 299v, L. rhamnosus GG and LB21, L. paracasei F19, L. reuteri PTA5289) were cultivated under anaerobic conditions at 37°C in Man Rogosa Sharpe (MSB) broth for 24 h. Four strains of human streptococci (S. mutans Ingbritt, S. mutans (ATCC 25175), S. mutans GS-5, S. sobrinus (ATCC 33478) were similarly grown in Brain Heart Infusion (BHI) broth. A gastrointestinal pathogen (Escherichia coli) was aerobically cultivated on BHI broth as a positive control. After incubation, the bacteria were aerobically harvested, washed, and suspended in 10 mmol/l phosphate-buffered saline (pH 7.2). The probiotic strains were characterized with the API 50 CH system to confirm their identity. Coaggregation was determined by spectrophotometry in mixtures and bacterial suspensions alone after 1, 2, 4, and 24 h and expressed as the aggregation ratio (%).All probiotic strains showed coaggregation abilities with the oral pathogens and the results were strain specific and dependent on time. S. mutans GS-5 exhibited a significantly higher ability to coaggregate with all the probiotic strains than the other mutans streptococci and E. coli. The differences among the probiotic strains were modest with L. acidophilus being the most prone and L. rhamnosus LB21 the least prone to coaggregate with the oral streptococci.The results demonstrated different abilities of lactobacilli-derived probiotic bacteria to coaggregate with selected oral streptococci. Aggregation assays may be a useful complement for screening of probiotic candidates with possible anti-caries properties.

The object of this review is to discuss the state of dental education and describe current developments at dental schools in the Nordic countries. The main focus is the undergraduate dental education; however, the postgraduate system will also be addressed. The curriculum model for undergraduate dental education in the Nordic countries is based upon the odontological tradition. The influence of biomedicine on dental education is increasing at present due to scientific and medico-technological developments and the altered disease profiles of oral and systemic diseases. These circumstances create new possibilities for dental education, but at the same time they raise some problems. In the long-term, the strong biomedical influence on dental education will be an advantage to future dentists' function and tasks in health care systems in the Nordic countries. In the short term, it may result in an identity crisis for dental schools, students, and our profession, as we experience the evolution from the traditional odontological curriculum model to one significantly influenced by ongoing changes in the biomedical field. Continuing professional education and advanced training in clinical specialties are likely to play important roles in this evolution.

The contamination level of alginate impressions delivered to a large dental laboratory in Sweden was determined. One hundred and seven consecutive alginate impressions were included during 7 days. Samples were taken and transferred into sterile physiological saline and analysed microbiologically for colony-forming units (cfu) as well as nonhemolytic, alpha-hemolytic, and beta-hemolytic colonies. After sampling, the clinics were contacted and asked to fill in simple questionnaires about their routines of disinfecting impressions. The questionnaire study revealed that about half of the clinics had some kind of disinfection routine, while the others rinsed in running water only. Seventy-two percent of the impressions yielded growth of bacteria, with a median number of 1.3x10(2) cfu. Thirteen per cent of the samples yielded10(3) cfu, with a maximum number of 3.4x10(4) cfu. The majority of isolates were non- and alpha-hemolytic bacteria. Growth was recorded in 61.3% of disinfected impressions, and the numbers of bacteria in disinfected and nondisinfected impressions were similar. These findings raise the question of whether impressions need to be disinfected or if proper handling and hygienic procedures are sufficient to block the possible route of infection.

The purpose of this study was to obtain a better understanding of probing measurements around osseointegrated oral implants. A comparison was made of probe tip position around Astra Tech implants and teeth of eight cynomolgus monkeys (Macaca fascicularis) in conditions of i) healthy peri-implant mucosa/gingiva, ii) mild mucositis/gingivitis, iii) severe mucositis/gingivitis or iv) peri-implantitis/periodontitis. Histological sections of 128 probes that were attached to implants or teeth with surrounding tissues were prepared by the cutting-grinding technique. No systematic differences were identified in the clinical and histological estimates of the distance between the mucosal/gingival margin and the probe tip. The differences were mainly smaller than 0.5 mm, and in no case were they larger than 0.7 mm. For implants and teeth with healthy peri-implant mucosa/gingiva, the distance between the probe tip and the alveolar bone was similar and ranged from 0.5 to 1.5 mm (P = 0.97). However, the probe tip was closer to bone around implants than around teeth in conditions of mild mucositis/gingivitis (P = 0.034), severe mucositis/gingivitis (P < or = 0.0001) and peri-implantitis/periodontitis (P < or = 0.0001). Around implants with severe mucositis and peri-implantitis, the distance was generally smaller than 0.5 mm, whereas teeth with severe gingivitis and periodontitis showed distances that mainly ranged from 0.5 to 1.5 mm. In conclusion, the probing measurements around osseointegrated oral implants and teeth were different. Even mild marginal inflammation was associated with deeper probe penetration around implants in comparison to teeth.

AIM: To investigate selected lifestyle factors in relation to active caries and restored root surface lesions in adults.MATERIALS AND METHODS: Based on clinical examinations and questionnaires, data on root caries, socioeconomic status, body mass index, dietary habits, alcohol consumption, tobacco use and oral hygiene routines were collected from 4369 adults aged 21-89 who took part in a survey covering 13 municipalities across Denmark. Uni- and multivariate logistic regression analyses were applied to analyse the relationship between the independent lifestyle variables and active caries and restored root surface lesions, respectively.RESULTS: The prevalence of active root caries was 4%, while 26% displayed restored root surfaces. The sugar intake was not related to root caries. A multivariate logistic regression analysis revealed that, in subjects aged 45 or over, smoking and wearing dentures were significantly associated with presence of active root caries (pCONCLUSIONS: Lifestyle factors such as tobacco use and alcohol consumption, as well as wearing dentures, were significantly associated with the occurrence of untreated caries and restored root surface lesions, especially in persons over 45. Thus, such lifestyle factors should be taken into consideration, identifying persons with a need of preventive dental services. In addition, oral health education should focus on the possible risks of smoking and a high alcohol intake.

Introduction Lifestyle and general diseases are important for the development of periodontitis and other diseases in the oral cavity. Therefore, knowledge on lifestyle factors must be part of the dental curriculum. However, a search for information in the literature databases gave meagre results. The aim of this study was to describe education of lifestyle in relation to diseases in the oral cavity with focus on periodontitis and to elucidate how education is practiced and reflected in dental education in the Nordic countries. Materials and Methods A questionnaire, which consisted of 18 questions, was sent to the chairs of the departments of periodontology in the Nordic countries. The questions concerned extent, curriculum structure, educational method, content, assessment and evaluation of the education. Results Education on lifestyle factors took place at all dental schools, but the extent, content and placement in the curriculum varied. In some schools, more than 10 lessons were scheduled; two schools had only 3–5 lessons. The education of lifestyle factors was prioritised highest in the departments of periodontology followed by cariology and general health. Despite differences in the content across the dental schools, there were also similarities. So, at all schools smoking, medication, cardiovascular diseases and diabetes type 2 had a high priority. Education of other factors such as alcohol, psychological stress, oral hygiene habits, hypotension and obesity varied. Conclusion Despite the general view that understanding of odontology is considered to be rather homogenous in the Nordic countries, the education varies across the dental schools. This variation may inspire dental educators in the future planning dental curricula.

The article concerns the dental education at 10 different faculties in Denmark, Iceland, Norway, Sweden, and Finland. The information is based upon a questionnaire to the faculties concerning the definition, the structure and succession of the basic science subjects/courses/themes/topics in the dental curriculum, the time span of the basic science teaching, and the methods of teaching. Furthermore, there is information about integration among the basic science subjects and the coordination/integration between the basic science teaching and the clinical teaching. Finally, the teachers' educational background and the cowork with the medical education is elucidated. The main findings are: the basic science teaching is structured in different ways in the Nordic countries. In Reykjavik, Bergen, and Aarhus this teaching is subject specific, while in Copenhagen it is mainly subject specific, as it has few integrated courses. In Gothenburg, Stockholm, and Umea, the basic science teaching consists of a mixture of integrated courses and subject specific teaching. In Helsinki, Oslo and Malmo the basic sciences are theme and topic based, and for the two last-mentioned institutions, integrated with the clinic, except at the faculty in Malmo. Here the basic science teaching is totally integrated in the clinical teaching throughout the study. Usually, the basic science teaching is placed mainly in the first part of the curriculum; however, in Umea, Copenhagen, and Oslo, some integration takes place.

Since the early 1980s, a number of large-scale, population-based, epidemiologic studies have focused on the development of disability, cognitive impairment, dementia, long-term care, and other health issues with particular relevance to older adults. With few exceptions, these health issues have been investigated in older populations, usually defined on the basis of chronological age (e.g., older than 65). Examples are the Established Populations for Epidemiologic Studies of the Elderly (EPESE), Women’s Health and Aging Studies (WHAS), and several other American, Australian, Canadian, and

Aim Periodontitis is a multifactorial disease in which subgingival bacteria play an important role in the pathogenesis of the disease. The objective of this study was to determine if periodontitis is associated with a characteristic salivary bacterial profile. This was accomplished by comparing the bacterial profile of saliva from subjects with chronic periodontitis with that of saliva from a control cohort. Materials and methods Stimulated saliva samples from 139 chronic periodontitis patients and 447 samples from a control cohort were analysed using the Human Oral Microbe Identification Microarray (HOMIM). Frequency and levels (mean HOMIM-value) of around 300 bacterial taxa/clusters in samples were used as parameters for investigation. Differences at taxon/cluster values between groups were analysed using Mann–Whitney U-test with Benjamini–Hochberg correction for multiple comparisons. Principal component analysis was used to visualize bacterial community profiles obtained by the HOMIM. Results Eight bacterial taxa, including putative periodontal pathogens as Parvimonas micra and Filifactor alocis, and four bacterial clusters were identified statistically more frequently and at higher levels in samples from periodontitis patients than in samples from the control cohort. These differences were independent of the individuals' smoking status. Conclusions Periodontitis is associated with a characteristic bacterial profile of saliva different from that of a control cohort.

Objective. The aims of the oral part of the Danish Health Examination Survey (DANHES 2007-2008) were (1) to establish an oral health database for adult Danes and (2) to explore the influence of general diseases and lifestyle on oral health. This paper presents the study population, examination methods, questionnaire and baseline results. Materials and methods. The study population comprised 4402 subjects, aged 18-96, consecutively enrolled from 18 065 DANHES participants from 13 municipalities in Denmark. The oral part consisted of a validated questionnaire and a clinical examination, carried out in mobile units by three trained and calibrated dental hygienists. The data were processed with descriptive statistics and mono-and bivariate analyses. Results. The mean age was 54.1 years and 60% were women. The mean number of natural teeth was 26.6; the mean DMFT/DMFS values were 18.9 and 61.0, and varied with age (DMFT 8.7-24.3). A higher proportion of females suffered from dental erosion in the younger age groups. Forty per cent of all subjects had a mean clinical attachment loss ≥ 3 mm, varying from 4% among those aged 18-34 to 80% in those over 75. A sub-optimal saliva secretion rate was more common among females than males (17.7% vs 10.4%) and this was reflected by the reported frequency of dry mouth. Conclusion. This extensive cross-sectional study provides a platform for obtaining future knowledge of the impact of health-and lifestyle-related factors on oral diseases. The validated questionnaire and the clinical characteristics enable robust analyses, although the conclusions may be hampered by limited external validity.

Bacteria living in biofilms as dental plaque on tooth surfaces are generally more resistant to antimicrobial agents than bacteria in batch culture normally used for in vitro susceptibility testing. In order to compare the resistance of free-living and surface-grown oral bacteria, the MIC of Streptococcus sanguis 804 and ATCC 10556 to amoxicillin, doxycycline and chlorhexidine was determined by a broth dilution method. Subsequently, S. sanguis biofilms established in an in vitro flow model were perfused with the antimicrobial agents for 48 h at concentrations equal to and up to 500 times the MIC, and biofilm cell number was determined during this period. The antibiotics at the MIC did not affect the cell number of S. sanguis biofilms compared to the starting point, and only after 48 h at 500 times the MIC were the biofilm bacteria eliminated. At intermediate concentrations biofilm cell number gradually decreased. Chlorhexidine also gradually reduced biofilm cell number, but was inhibitory at concentrations closer to the MIC than was the case for the antibiotics. Thus S. sanguis in biofilms survived up to 500 times the MIC found in batch culture for up to 48 h.

Longo Vital® herbal tablets have been shown to have a protective effect against periodontal bone loss in rats. This may be ascribed either to a previously demonstrated immuno-stimulatory effect of the tablets, to an antimicrobial effect of the herbs or to a combination of both. In the present study the in vitro susceptibility of 12 dental plaque bacteria to six individual herbs included in Longo Vital® was determined by a broth dilution method. Paprika, rosemary leaves and peppermint inhibited two thirds of the tested bacteria at 2.8-45 mg/ml, 0.75-12 mg/ml and 3-24 mg/ml corresponding to 0.8-12.5 per cent, 1.6-25 per cent and 12.5-100 per cent of the recommended daily dose, respectively. A combination of paprika and rosemary leaves tested towards five susceptible bacteria revealed a decreased inhibitory effect on two of these bacteria, especially of Actinobacillus actinomycetemcomitans to paprika, but conversely a pronounced increase in susceptibility of Peptostreptococcus anaerobius, Porphyromonas gingivalis and Prevotella intermedia now susceptible to 0.01-0.70 mg/ml of each herb, corresponding to 0.02-0.2 per cent of the recommended daily dose. The active ingredients of the herbs, however, and the concentrations of these obtained in blood and periodontal tissues after ingestion of Longo Vital® are not known.

In the present study DNA restriction patterns and corresponding ribotypes of 17 subgingival small-sized spirochetes (1:2:1 and 2:4:2 isolates), 2 Treponema socranskii strains and two Treponema denticola strains were examined. Purified chromosomal DNA was digested by BamHI, HindIII, PstI and ClaI. The DNA fragments were separated in a horizontal slab of 0.7% agarose containing ethidium bromide and transferred by nylon membranes. Hybridization was carried out with digoxigenin-labelled copy DNA of 16S and 23S ribosomal RNA from Escherichia coli. Depending on the restriction endonuclease used, up to 4 distinct bands were observed for the 2:4:2 isolates and the T. denticola strains. For each of the endonucleases used, identical band patterns were always observed for this group of isolates, and these patterns differed persistently from the T. denticola strains. For the 1:2:1 strains, up to 11 distinct bands were observed after digestion with HindIII, whereas a maximum of 6 bands were observed when PstI or ClaI was used. By using ClaI, the examined 1:2:1 isolates were separated into 8 groups, whereas PstI and HindIII separated these isolates into 5 groups. The ribotyping showed that the tested 1:2:1 spirochetes were more heterogeneous than the 2:4:2 spirochetes examined.

In 2005, a new curriculum was introduced at the School of Dentistry at the University of Copenhagen. Amongst many changes, the pedagogical concept behind theoretical teaching was changed. The main emphasis was previously on lectures and teacher controlled teaching, but the emphasis has now shifted to a more dialogue-based teaching style for smaller groups where the students became much more active. Thus, the learning principle was now given the pride of place. The present article focuses on the pedagogical reorganisation of the course in oral microbiology where, based on interviews with students and teachers, an evaluation is made regarding how the changes were implemented and developed. Despite the fact that the students themselves wanted to abandon the lecture-based teaching style, there was great dissatisfaction with the new dialogue-based teaching style as the students did not think that it was possible for them to take responsibility for their learning. They would much rather listen to teachers who know the material. Initially, the teachers were very surprised by the negative attitude of the students and had to change the teaching style to more traditional teaching in groups whilst still maintaining the dialogue principle to a certain degree. In this article, the need to enter into a teaching contract between students and teachers prior to introducing new pedagogical principles is discussed.

Objectives To identify and analyze determinants for oral-health-related quality of life among adults admitted to a Danish research program on general health and lifestyle (DANHES 2007-2008) Materials and methods Study population of the present (dental) study: 4402 volunteers invited among participants of main study (n18065) covering 12 different Danish cities. Age 18-96 years (average 54) Structured interviews (from main study and dental study) and clinical oral examination Oral-Health-Related Quality of Life measured by a 10 item index Non-parametric statistical methods, chi-square, simple and multivariate logistic regression Data are not representative to the Danish population, however, associations between outcome and independent variables are considered valid. Regular dental visits and high number of natural teeth are determinants for a high level of Oral-Health-Related Quality of Life Untreated caries, wearing dentures and high caries experience are determinants for reduced Oral-Health-Related Quality of Life Results 33 persons were edentulous, Mean DMFS = 62, 7 % wore dentures 88% were regular users of the dental care system 24 % reported Oral-Health-Related Quality of Life problems 6 % reported a score of 3 or more Oral-Health-Related Quality of Life problems (maximum score = 30) Most frequent problems were: Feeing embarrassed because of the appearance of teeth (or dentures) 13 % Difficulties with eating food due to mouth or teeth problems 9 % Feeling tense because of the appearance of teeth (or dentures) 9 % Avoid smiling/laughing because of the appearance of teeth (or dentures) 6 %

The purpose of the present study was to determine the surface hydrophobicity of small oral spirochetes and to receive an impression of the molecular organization of the cell surfaces. Nine spirochete strains with one endoflagellum from each cell-end (1:2:1 spirochetes) and eight with two endoflagella from each cell-end (2:4:2 spirochetes) from subgingival plaque were examined. Two hydrophobicity assay systems were used: 1) two-phase partitioning and 2) salting-out aggregation by ammonium sulfate. The influence of heat, enzymes, saliva, and serum were examined. The 2:4:2 spirochetes were significantly more hydrophobic than the 1:2:1 spirochetes. For all strains heat treatment increased surface hydrophobicity, whereas incubation with proteases decreased surface hydrophobicity for the 1:2:1 spirochetes. The 2:4:2 spirochetes were unaffected by the proteases. Lipase and hyaluronidase affected the two morphotypes in opposite directions. Saliva did not affect the surface hydrophobicity of any of the strains, whereas rabbit serum decreased this property for the 2:4:2 strains.

– Different bacterial profiles of subgingival plaque have been described for different clinical categories of marginal periodontitis. In the present investigation the subgingival microflora was studied in young adults with advanced marginal periodontitis. From 12 patients pooled subgingival plaque samples from 5 advanced stages of diseased sites were examined by direct differential phase-contrast microscopy and by cultivation on enriched and selective media. The proportions of the following genera and species were calculated: black-pigmented Bacteroides sp., B. gingivalis, Fusobacterium nucleatum, Veillonella sp., Actinobacillus actinomycelemcomitans, Capnocytophaga sp., Eikenella corrodens, Campylobacter sp., and Candida sp. Spirochete identification was carried out ultrastructurally. Calculated percent minimum similarity levels between the individuals revealed that each patient harbored its characteristic cultivable subgingival microflora different from the other individuals. The spirochetes seemed to constitute the subgingival bacterial group with the smallest variation as certain morphotypes were dominating in almost all individuals.

Epidemiological studies have shown that periodontitis may be associated with presence of atherosclerosis. DNA from periodontal pathogens has been detected in atherosclerotic lesions, but viable oral bacteria have not yet been isolated from atherosclerotic plaques. The purpose of the present study was to determine if viable oral bacteria could be isolated from atherosclerotic lesions and if DNA from periodontal pathogens could be detected by use of polymerase chain reaction (PCR) techniques.Seventy-nine specimens of atherosclerotic plaque removed from carotid or femoral arteries during surgery were immediately transferred to reduced transport fluid and brought to the laboratory. The calcified tissue was meticulously cut into fine pieces and used for cultivation of Porphyromonas gingivalis, Prevotella intermedia, P. nigrescens, Campylobacter rectus, Actinobacillus actinomycetemcomitans, Tannerella forsythensis, and oral streptococci. The material from 24 of the specimens was homogenized, DNA was extracted, and PCR amplification of 16S rDNA with universal and specific primers was carried out. Finally, the PCR products were sequenced.None of the samples yielded growth of the oral bacteria under investigation. In all the 24 specimens bacterial DNA was detected and likewise DNA of P. intermedia was found in the samples. P. nigrescens and P. gingivalis were found sporadically.Viable oral bacteria could not be isolated from the atheromas, but the data confirm that DNA of periodontal pathogens can be detected in atherosclerotic plaques. However, the finding that DNA from P. intermedia constantly occured in the examined samples was new. Further studies may focus on the simultaneous occurrence of identical clones of this species in subgingival plaque and atherosclerotic plaques.

To evaluate the effect of a disinfectant agent based on hydrogen peroxide (Sterilex Ultra, Sterilex Corporation, Maryland, USA) on the microbiological water quality in dental unit waterlines (DUWL).Six older dental units were disinfected with Sterilex Ultra and another six units with sodium hypochlorite. The results were compared to six non-disinfected units examined during a period without patient treatment.The number of colony forming units of bacteria (cfu)/ml of water was determined according to European Standards on water quality.The water quality was initially determined during a six week period, and subsequently in more detail for two weeks. Finally, the effect of prolonged administration of Sterilex Ultra was investigated for six weeks.Instillation of Sterilex Ultra according to the recommendations of the manufacturer initially reduced the number of bacteria in DUWL to10(2) cfu/ml. However, following daily, as well as prolonged administration of Sterilex Ultra a gradual recolonisation was observed resulting in bacterial numbers10(4) cfu/ml in a number of units. Major differences between the number of cfu/ml in individual units were observed.Neither daily nor extended administration of Sterilex Ultra was capable of maintaining an acceptable water quality in these older dental units.

An association between periodontal infection and CVD has been revealed in some epidemiologic studies, whereas other studies were unable to demonstrate such an association. A link between the two diseases may be explained by shared established or nonestablished risk factors. Future studies with extended control of confounding factors and intervention studies may add to the understanding of a possible relationship between the diseases. In some cases, IE is caused by dental plaque bacteria. Several studies are suggestive of oral bacteria causing respiratory infection. The pathogenesis and course of a number of other diseases including DM and rheumatoid arthritis have been associated wish periodontitis, but more research is necessary to elucidate possible pathogenic interactions.

The purpose of this study was to determine the risk of microbiological transmission into the dental laboratory via impressions and dental stone models. Metal master models were contaminated with Bacillus subtilis and Streptococcus sanguis. Impressions in alginate, polyvinylsiloxane, and polyether were used, and models were cast in two brands of dental stone. Samples were taken from the impression surfaces before and after casting, and sections from the stone models were taken by a technique developed for this study. After incubation, the numbers of colonies were counted and the numbers of colony-forming units per milliliter were calculated. The reductions were statistically significant but considered to be clinically insignificant. The conclusion is that even after severe contamination, the risks to dental laboratory personnel are minimal. "Normal" hygienic procedures are recommended instead of disinfection.

A binding assay was developed and used to study the binding of oral streptococcus to immobilized human fibronectin, laminin, vitronectin, fibrinogen, heparin, and collagen IV. The protein binding was dependent on the broth used for bacterial growth. The binding after growth in brain heart infusion broth, trypticase soy broth, Todd-Hewitt broth, and Dulbecco's modified Eagle's medium was examined. Most of the strains were able to bind to immobilized fibronectin and laminin, and to a minor extent vitronectin. Binding was not observed on immobilized fibrinogen, collagen IV, or heparin. Measured surface hydrophobicity correlated well with the bacterial binding strength to the proteins. Streptococcal incubation with putative inhibitors indicates multiple binding mechanisms of a lectin-like and protein nature, possibly involving protein receptors.

Objective. It has been demonstrated that contamination of the insides of high-speed dental turbines occurs and that bacteria as well as viruses may remain infectious when expelled from such turbines during subsequent use. Consequently, it has been widely recommended that a high-speed turbine be sterilized after each patient. The purpose of this study was to evaluate the effect of steam autoclaving on a high-speed dental turbine with a contaminated turbine chamber. Study Design. Streptococcus salivarius and endospores of Bacillus stearothermophilus were used as test organisms to determine the effectiveness of 4 different small non-vacuum autoclaves and one vacuum autoclave. Results. The study demonstrated different efficiencies among the small non-vacuum autoclaves, the best showing close to a 6 log reduction of the test organisms inside the turbine chamber. When cleaning and lubrication of the high-speed dental turbine was carried out before autoclaving, this level of reduction was observed for all the examined non-vacuum autoclaves. Conclusions. It is concluded that cleaning before sterilization is essential for safe use of high-speed dental turbines and that small non-vacuum autoclaves should be carefully evaluated before being used for the reprocessing of hollow instruments such as high-speed turbines. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999;87:184-8)

Dental high-speed turbines and handpieces can take up and expel microorganisms during operation and thus need regular sterilization. This study established a method for validating devices used to sterilize high-speed turbines and handpieces. The air and water channels and turbine chambers were contaminated with suspensions of Streptococcus salivarius or endospores of Bacillus stearothermophilus. The effect of flushing and/or autoclaving performed by a new device combining both procedures was evaluated by counting the number of viable bacteria recovered from these devices. Further, the effect on clinically used handpieces was evaluated. In an initial experiment, the device partially reduced S. salivarius, and the endospores survived. In a second experiment, a 5 to 6 log reduction of S. salivarius in air and water channels was obtained. No growth was observed in clinically used high-speed handpieces, and both S. salivarius and endospores were eliminated from the turbine chambers. Thus, the method of validation proved capable of discriminating between different levels of bacterial reduction.

By local delivery of antibiotics to periodontal pockets, very high initial concentrations are often quickly succeeded by subinhibitory concentrations, which may facilitate development of bacterial resistance. The purpose of the present study was to investigate possible development of resistance in suspected periodontal pathogens after exposure to subinhibitory concentrations of metronidazole and minocycline. The minimal inhibitory concentration (MIC) of 18 reference strains and 12 clinical isolates was determined by a broth dilution method. Subsequently, all strains with MIC8 micrograms/ml were exposed to serial passage on plates containing subinhibitory and gradually increasing concentrations of antibiotics, until growth was inhibited. Initially, most strains were inhibited ator = 0.250 microgram/ml of minocycline andor = 0.5 microgram/ml of metronidazole, though A. actinomycetemcomitans was resistant to metronidazole. After growth at subinhibitory concentrations, 8 strains survived 1-2 x and 11 stains survived 8-32 x their initial MIC of metronidazole, growing at up to 8 micrograms/ml. All A. actinomycetemcomitans survived 8-64 x their initial MIC of minocycline, growing ator = 2 micrograms/ml, while all other strains were inhibited ator = 0.250 microgram/ml, corresponding to a 1-8 x increase in their initial MIC. Thus, development of resistance was observed for periodontal bacteria growing at up to 64 x their initial MIC, but the final level of resistance was moderate.

A group of 1:2:1 and 2:4:2 subgingival spirochetes, well characterized by transmission electron microscopy, biochemical tests, cellular fatty acid and carbohydrate analyses, and ribotyping, was recently suggested to represent new treponemal species. The present study used DNA hybridization to examine this possibility. When DNA of a representative strain (no. 16) of the 8 1:2:1 spirochetes examined was labeled by iodination, it showed, after S1 nuclease treatment, from 58 to 104% (average 76%) homology with DNA from the 1:2:1 spirochetes, 94% homology with DNA from the type strain of Treponema socranskii and of T. socranskii subsp. socranskii, i.e., ATCC 35536T, and 62% homology with DNA from T. socranskii subsp. buccale, strain ATCC 35534T. Similarly treated DNA from a representative strain (no. 3) of 8 2:4:2 spirochetes exhibited from 90 to 105% (average 97%) homology with DNA from the 2:4:2 spirochetes, and 85% and 87% homology, respectively, with DNA from Treponema denticola strains ATCC 33520 and FDC T1. There was a negligible degree of homology between the 1:2:1 and 2:4:2 spirochetes. Thus, all the 2:4:2 spirochetes belonged to T. denticola. 1:2:2 strains with DNA homology levels >70% (5 strains) belonged to T. socranskii or T. socranskii subsp. socranskii, while those with homology levels from 58 to 63% (3 strains) most likely belonged to other subspecies of T. socranskii.

Bacteria in biofilms are known to be more resistant than bacteria in batch cultures to antimicrobial agents. The purpose of the present study was to develop a flow method for formation of oral biofilms permitting susceptibility testing of plaque bacteria. A brain heart infusion (BHI) Streptococcus sanguis 804 culture was pumped through a modified Robbins Device (MRD) with 25 exchangeable silicone disks at 40 ml/h. After 24-48 h disks were removed and biofilm cells dispersed by vortex mixing and low-output ultrasonication. Colony forming units (cfu)/cm2 were determined after aerobic incubation on blood agar plates. Optimal biofilm formation was found after growth for 48 h at 37 degrees C in BHI + 1% sucrose, using saliva-coated silicone disks in inverted MRDs, yielding on average 4.4 x 10(5) cfu/cm2. Similar results were obtained for S. sanguis ATCC 10556 and five clinical isolates. Testing the susceptibility of S. sanguis to chlorhexidine gluconate showed increased resistance of biofilms compared to batch culture. Thus an appropriate biofilm model for susceptibility testing of oral microorganisms has been established.