Antibacterial activity of yoghurt against viridans streptococci in vitro.

OBJECTIVE: Yoghurt consumption leads to a selective decrease in the oral level of mutans streptococci. It is not clear whether this decrease is due to the bactericidal activity of yoghurt or other mechanisms. The present study investigated the differences in susceptibility to yoghurt between several strains of viridans streptococci. DESIGN: The sources of variation were minimised, at the expense of the external validity of the study, using culture collection strains. Each strain was tested separately on five occasions in planktonic form and logarithmic growth phase. Two strains of each of the following Streptococcus species were tested: mutans, sobrinus, gordonii, oralis, parasanguinis and sanguinis. One millilitre [10(8) colony-forming units (cfu)] of each strain was incubated (37 degrees C, 60min) with 9mL of fat-free plain yoghurt containing Streptococcus thermophilus and Lactobacillus bulgaricus (10(8) and 10(7)cfu/g, respectively) in gently vortexed tubes. Survival rates were calculated every 15min by dividing the number of viable cells, obtained using conventional laboratory procedures, by the baseline number. RESULTS: Survival rates were 8% (S. mutans 6519T), 12% (S. mutans 31738), 35% (S. oralis 25671) and >50% (all other species tested) after 15min, and 0.01% (S. mutans) and >10% (all other species tested) after 30min. Overall, S. parasanguinis and S. sobrinus were the most resistant species. When heat-treated yoghurt (<10cfu/g bacteria and inactivated bacteriocins) was used, this antibacterial activity was not found. CONCLUSION: In vitro, yoghurt with live bacteria showed selective anti-mutans activity, suggesting that the overall decrease in mutans streptococci in vivo could be due to a bactericidal effect on S. mutans but not on S. sobrinus.

[Health-related behaviour and HCV prevalence among elderly and younger adults in an isolated community close to Rome (Italy)]. / Abitudini comportamentali e prevalenza di HCV in anziani e giovani di una comunità del frusinate.

The aim of this study has been to investigate the differences in the health-related behaviour by means of a questionnaire in a sample of elderly (>54 years, 1st generation) and younger adults (<54 years, 2nd generation, all of them sons/daughters of HCV positive subjects), given the high difference in HCV positive prevalence among the two groups (19.4% vs. 2.1%). Most (53.4% vs. 0.0%) of the 1st generation subjects used glass syringes while all the 2nd generation subjects used disposable syringes. Among the elderly, the frequency of hospitalisation (70% vs. 50%), transfusions (11.8% vs. 2.9%) and dental therapy by false dentists (52% vs. 0%) were higher. These results show that the use of non recyclable syringes is the main responsible for the drastic reduction of HCV circulation in the present community, and the consequent decrease in the risk for infection in younger subjects. Moreover, dental therapy was not related to an increased risk for infection, providing that the treatment has been made by a "true" dentist. Finally, the intrafamiliar transmission was not supported by the present data.

The effect of milk and sucrose consumption on caries in 6-to-11-year-old Italian schoolchildren.

The effect of milk on dental caries was studied on a sample of 6-to-11-year-old Italian schoolchildren. The daily amount of milk consumed and the frequency of consumption of sucrose-containing foods were obtained by a 24-hour dietary diary. In the subsequent oral examination, the level of visible plaque and the number of decayed, extracted and filled teeth (both primary and permanent) of the children were recorded. 439 children (217 boys) who did not use fluoride prophylaxis and with poor oral hygiene were selected from among 890 children. They were divided into three groups according to the frequency of sucrose consumption. The data were statistically analysed using multiple logistic regression. The children consumed a daily average of 209 +/- 133 ml of milk and there were no differences among the three groups in this respect. As expected, the dental health of the children with low sucrose frequency was significantly better than that of the children with high sucrose frequency. The regression on the whole sample showed a weak, significant, negative association between milk consumption and caries (p < 0.05). In the group of high sucrose-consuming children a negative, highly significant association was found (p < 0.001), while in the two groups of low and moderate sucrose-consuming children no association was found. These data suggest that, in the present sample of children who did not use fluoride and with poor oral hygiene, milk has a caries preventive effect only on those subjects with a high daily sucrose-consuming frequency.

Effect of orthodontic therapy with fixed and removable appliances on oral microbiota: a six-month longitudinal study.

The present study evaluated microbiological and clinical changes occurring during the first six months of orthodontic therapy with fixed and removable appliances and the consequent risk for gingivitis and periodontal disease. This study was justified by the disagreement among different authors: only some of them reported gingivitis development and changes in dental plaque composition during orthodontic therapy with fixed appliances, others did not. Thirty, 7-to-15-year-old children, fifteen with fixed and fifteen with removable appliances, previously motivated to oral hygiene, completed the study. They were clinically examined by a dentist at baseline and at the end of the study. Three supra and subgingival microflora samples were collected from the first molars, when the appliances were inserted (T0), 6-8 weeks later (T1) and 6-7 months later (T2). Microflora was examined using dark-field and light microscopes and cultural methods. An indicator of healthy status (percentage of Gram positive cocci in total bacterial count) and some risk indicators for gingivitis (bacterial count evaluated with light microscope, percentage of Gram negative rods) and for periodontitis (motile rod and spirochete percentages, presumptive Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis prevalence) were investigated. Patients with fixed appliances were clinically healthy at T2; yet they showed significantly increased counts, motile rods, subgingival spirochetes and a decrease of Gram positive cocci. At T2, patients with removable appliances were clinically healthy and the only significant microbiological changes were supragingival motile rods and subgingival spirochetes. These data suggest that in the oral hygiene motivated patients of the present study, gingivitis and periodontitis do not occur, during the first six months of treatment: the significant modification of oral microbiota, shown by subjects with fixed appliances, however, suggests that the risk for gingivitis in the following months of therapy is still high and the risk for periodontitis cannot be excluded.

[Use of a microwave device for dental instrument sterilization: possibilities and limitations]. / L'impiego di un apparecchio a microonde nella sterilizzazione di strumentario odontoiatrico: possibilità e limiti.

BACKGROUND: The aim of the present study was the evaluation of the effectiveness as sterilizer of a modified version of a microwave device, which was previously tested by the same authors and found unsatisfactory. MATERIALS AND METHODS: Dental mirrors were contaminated by 10(4)-10(9) microorganisms of Stapbylococcus aureus and spores of Bacillus subtilis and Bacillus stearothermophilus. The inocula used were both wet and dry. The duration of the treatment was 4 minutes. Three series of tests were made: 1) microwaves and "adjuvant" solution (as suggested by the producer of the device); 2) microwaves only (in place of the "adjuvant" solution, a Na Cl 0.9% was used); 3) "adjuvant" solution only (into an oven at 25 degrees C). RESULTS: In the 1st and 3rd series of tests all the microorganisms and the spores were killed. In the 2nd series of tests a bactericidal effect against some, not all, microorganisms of the S. aureus species and against spores of B. subtilis and B. stearothermophilus was found. CONCLUSIONS: The results of this study suggest that the device tested has a sterilizing activity, which, however, is not due to the activity of microwaves only; but to the combined activity of microwaves, "adjuvant" solution and temperature (since inside the device, at the end of the treatment the temperature on the mirrors was 94 degrees C).

[A new device for the disinfection of handpieces and turbines]. / Su un nuovo apparecchio per la disinfezione di manipoli e turbine.

Dental handpieces are often difficult to disinfect. This is one of the main reasons for the considerable risk of cross-infections in dental offices. The aim of the present study was the evaluation of the disinfectant property of a recent, commercially available, automatic instrument, described as capable to clean, disinfect and lubricate dental handpieces. The following experimental evaluations were made: 1) antimicrobial activity of the disinfectant (glyoxalaldehyde) used. The method described by the European Committee for Standardization was followed. Test microorganisms were Pseudomonas aeruginosa and Staphylococcus aureus. 2) disinfection of dental handpieces (69 contra-angles and 97 turbines of different marks). They were naturally infected using them on patients for 30 minutes at least. 3) disinfection of dental handpieces infected with bacterial suspensions of Staphylococcus aureus, Streptococcus pyogenes (beta-haemolyticus, group A), Candida albicans and Pseudomonas aeruginosa. The results of the first experiment showed a strong bactericidal power of the disinfectant with both the tested strains, after a contact time of only 1 minute. A great proportion of the dental handpieces tested during the second experiment were found disinfected: from 84% through 89% out of the various models of turbine handpieces; from 89% through 100% out of the models of contra-angle handpieces. Even though bacterial contamination level was low (about 10(3) microorganisms per handpiece), a satisfactory disinfectant ability in natural conditions was found. The results of the third experiment were unclear. The tested instrument reduced 10(5)-10(8) times the original bacterial count when the gram positive microorganisms (Staphylococcus aureus, Streptococcus pyogenes) were used. On the other hand, when Pseudomonas aeruginosa and Candida albicans were used, the results were different: the bacterial count was reduced 10(6)-10(7) times in some cases, and only 10(2) times in other cases. This difference was found in the tests made using the same attachment and in those made using various attachments. In conclusion, the tested instrument showed, in most cases, a good disinfectant property, but the presence of unclear results suggests that some technical modifications are required.

[3 different methods for evaluating Streptococcus mutans in the saliva]. / Su tre differenti metodiche di valutazione dello Streptococcus mutans nella saliva.

Three different methods for detection and count of Streptococcus mutans in saliva have been compared with a microbiological method in order to estimate their efficacy and practicality. The study has been carried out on fifty children of six-eleven years old. The first method (stamp method) derives from that of Kohler and Bratthall, improved on the sampling, without saliva stimulation and, hence, more rapid. Furthermore, using a tongue depressor with a shovel-like extremity, we can either restrict the area where the grown colonies must be counted, avoiding any mistake, and stamp the spatula in the centre of the plate, not in the border, as the original method described, pressing it with the same force in every part, so that almost all the saliva collected can be plated on the Streptococcus mutans selective medium. As stated by this method, a tongue depressor is pressed first on the subject's tongue, then on a plate containing the medium. After incubation, the Streptococcus mutans colonies are counted on the plate's area limited by the stamp of the extremity of the spatula. According to Emilson we can also discriminate Streptococcus mutans and Streptococcus sobrinus colonies. The second method is a "strip mutans test" (Dentocult): saliva is stimulated making the subject chew a piece of paraffin and then it is collected passing a plastic spatula for ten times on the child's tongue. The spatula is introduced into a tube containing a liquid medium selective for Streptococcus mutans and then incubated.(ABSTRACT TRUNCATED AT 250 WORDS)

[Nutritional hygiene in the prevention of dental decay: thoughts about weight gain in children in elementary schools]. / L'igiene alimentare nella prevenzione della carie dentale: riflessi sull'accrescimento ponderale in alunni della scuola elementare.

Hereafter the results of an investigation carried out in two elementary schools, centred on a health education programme divided into oral hygiene and nutritional hygiene interventions, having the aim above all of assessing the effectiveness of otherwise of such interventions for purposes of checking up on dental caries. Parallel to this main aim we also wished to verify the validity of a working hypothesis which, departing from a strictly odontological aspect, also aimed at pointing out the influence or otherwise of such food education interventions on a more harmonious growth in weight of the children concerned in the programme. This was because most of the principles underlying food education interventions in the strictly auxological field coincide with the basic principles of interventions aimed at the prevention of caries. The programme was prolonged for three school years in two elementary school of Rome coming under the same Local Health Service. This note concerns the second point on the programme, namely study of the body growth pattern. The results may be summarised as follows: At the beginning of the experiment the control group showed a maximum concentration of children in the "normal weight" class (38.9%) and a progressive decrease towards the extreme classes. Whereas in the experimental sample the spread was less regular, with a smaller percentage of children in the "normal weight" (22.9%) a maximum concentration in the "slightly overweight" class (30%) and a distribution of pupils progressively decreasing towards the extremes, but with a slight preponderance towards the Overweights. At the end of the experiment the control group showed a clear reduction in the "normal weight" class (from 38.9% to 30.6%) and at the same time an increase in all the adjacent classes (with the "slightly overweights" rising from 19,45% to 22,21%, and the "seriously overweights" from 9,72% to 13,9%, the "slightly underweights" from 18,06% to 23,62% to 23,62%; while a fall in the "very seriously underweights" was recorded (from 5,56% to 2.78%), with the "seriously overweights" remaining practically unchanged). Whereas in the experimental group we found a better redistribution by classes, with the greatest concentration of pupils in the "normal weight" class (from 22.86% to 41.43%), the only significant increase (p less than 0.01), and considerable falls in the "slightly overweight" class (from 30.0% to 21.44%) and in the "slightly underweight" class (from 20.0% to 12.86%); while the "seriously overweights" continued to gather a large percentage of children (from 18.58% to 20.00%).(ABSTRACT TRUNCATED AT 400 WORDS)

[Epidemiologic approaches, in school health education programs with particular attention to dentistry]. / Approccio epidemiologico per interventi di educazione sanitaria nella scuola con particolare attenzione al campo odontoiatrico.

At the request of the Cultural Union of the Upper Aniene Valley, the social-health workers dealing with school medicine of the Teaching District of Affile (Rome) have tried to define the programming lines for a health education intervention in the elementary schools of the district. The basic requisites of the intervention were pinpointed as: effectiveness, in terms of improvement of health conditions; short-term results; cognitive-transformative methodology having a spiral progression (cognitive, decision-making, implementative and of verification). The departure point of the intervention was the cognitive study on the social-health situation of the school population based on an analysis of the individual data contained in the medical files compiled by the school doctor, standardised and filled out with the pupils' social and family data. Out of 257 children, 212 were examined, namely 82.4% of the school population. The first social-anamnestic data on pupils' families was in respect of parents' level of education, giving the following results: 65% with elementary schooling only, 11% semi-illiterate and 10.5% diploma- or degree-holders. In respect of parents' working activities, on the other hand, a clear difference emerged: compared with 50.4% of worker or artisan fathers and about 33.3% engaged in the tertiary sector, almost all the mothers were still home-based (90.9% housewives). Another interesting fact emerged from the cards, namely that only 69% of the boys and girls have undergone the full cycle of antidiphtheria-antitetanus vaccinations, and only 80% of antipolio vaccinations. As regards pupils pathological anamnesis, cases of hospitalisation were for the following causes: 5.7% fractures and/or burns, followed by intestinal infections (4.5%). Whereas, as regards current pathology the high incidence of a cariogenic pathology emerged, with such high values as to indicate, in the field of prevention and health education, oral hygiene as the priority intervention to be undertaken in respect of the pupils included in the teaching district. The stages of the planned intervention were fixed as follows: -campaign to make teachers and families, considered as the primary educators, aware of this health problem; -meetings with pupils for the purpose of informing them in a simple way of the problem of caries and of discussing together behaviours liable to ensure greater dental hygiene; -involvement of the school and local administrative authorities for the implementation of any measures aimed at favouring the improvement of the behavioural and eating habits of the boys and girls (access for all to school canteens, free dental examinations, etc.).(ABSTRACT TRUNCATED AT 400 WORDS)