the prevalence of cariogenic salivary micro-organisms in children of various ages

Th e objective of the research was to obtain data on the values of salivary Streptococcus mutans and Lactobacillus spp. in  years old children and teenagers ( –  years old children), and to compare the values of these cariogenic microoorganisms in children of various ages, for the purpose of valuating the risk of caries. Th e sample comprised  persons divided into two groups. Th e fi rst group included  children of the age of . Th e second group included  teenagers. Th e specimen of stimulated saliva, needed for the purpose of establishing the quantities of Streptococcus mutans and Lactobacillus spp., was taken by the method of CRT®-bacteria, according to manufacturers


Introduction
Mutans streptococci are a heterogeneous group of microorganisms divided into  species and  serotypes (,).Th ey make normal micro fl ora in oral cavity.Th ere exist several types of Streptococca, isolated from human dental plaque.Th e most common type is Streptococcus mutans (serotypes c, e and f), and Streptococcus sobrinus (serotypes d, g).Th ey are connected with the development of caries in humans and animals (, ).Streptococcus mutans belongs to the group of Alfa hemolytic streptococci.Mutans streptococci are related to the occurrence of early demineralization, i.e., initial phases of the development of caries ().In consequence of some of their vital characteristics, mutans streptococci are regarded potentially highly cariogenic: they are acidogenic (capable of producing acids that melt the tooth substance), aciduric (able to survive, grow and perform metabolic processes in the environment of very low pH), they have the capacity of creating extracellular polysaccharides, capability to transport sugar, capability to adhere to dental surfaces ().Mutans streptococci infections are globally distributed.These microorganisms can be found in almost all humans in a population; however, in diff erent persons, the levels of mutans streptoccoci vary from low to very high values.Th eir values in individuals are determined by the irregularities on the surface of tooth enamel, retention areas, as well as genetic and immuno-biological factors.Mutans streptococci are microorganisms that primarily colonize dental surfices.In the concentration of   -  CFU/ml in saliva, Streptococcus mutans is able to colonise clean, smooth surface of a tooth.Th e presence of mutans streptococci on tooth surfaces increases the possibility that caries would develop thereon.Lactobacilli belong to the group of Gram-positive microorganisms.They are isolated as a part of normal human microflora.They are acidogenic and aciduric.As early as , W.D. Miller proved the presence of lactobacilli in oral fl ora, and their capacity of producing acids.There are several kinds of lactobacilli, but the most common types found in oral fl ora are Lactobacillus rhamnosus and Lactobacillus casei.Lactobacilli alone have no important role in the initiation of caries ().Lactobacillus is a secondary invasive bacteria connected with the progression of caries lesion.It is most commonly found in the dentine, in deep portions of carious lesion, in open cavities, but also in retention areas on teeth like, for example, poorly made edges of dental fillings.The saliva of persons that have active carious lesions, usually contains a large number of Lacobacilli spp.; however, lacobacilli as a part of normal fl ora can also be found in persons that have no caries ().Infection with Lactobacilli has a global distribution.The levels of lactobacilli vary in different persons.The persons with a high level of Lacobacilli spp.have, or develop more carious lesions than those with lower levels of lactobacilli (,).Th e levels of Lactobacillus spp.and Streptococcus mutans in saliva indirectly point towards the risk that a new carious lesion would develop (), so they are used as parameters in the assessment of caries risk.The objective of the research was to obtain data on the values of salivary Streptococcus mutans and Lactobacillus spp. in  years old children and teenagers ( - years old children), and to compare the values of these cariogenic microorganisms in children of various ages, for the purpose of assessing the risk of caries in these population groups.

Materials and Methods
The sample comprised  persons divided into two groups.The first group included  children of the age of .The second group included  teenagers ( - years old children).The following criteria were applied in the selection of participants: -Patient did not use antibiotics  weeks before the testing.
-No changes exist in the structure of tooth enamel.
-No active carious lesion exists Both groups of patients were the children coming from good-income families, who regularly maintain oral hygiene by brushing their teeth at least twice a day.All respondents had their teeth sanitized with dental fillings, without a single carious lesion.Th e levels of salivary Streptoccocus mutans and Lactobacillus spp.were determined for each individual patient.Th e sample of stimulated saliva, needed for the purpose of establishing the quantities of Streptococcus mutans and Lactobacillus spp., was taken by the method of CRT ® -bacteria (Ivoclar-Vivadent ® clinical), according to manufacturer instruction.Patients were given a piece of (factory-made) wax, which they chewed for  minutes in order to collect enough stimulated saliva (during wax chewing, the process of bacteria mobilization happens, from the plaque into saliva).While chewing, the respondents collected saliva into disposable plastic cups.After  minutes, disposable pipettes were used to take saliva and seed it on slides for Streptococci mutans and Lactobacilli spp.Firstly, after the protective coat was removed from sterile slides,  drops were neatly dripped on the slide (until its entire surface was cov-ered in saliva), which was held under a slight angle, taking special care not to damage the surface of the slide with the sharp edge of pipette.Once the procedure was over, a tablet of NaHCO  was put in slide boxes, and then the boxes were closed and placed into incubator at the temperature of °C. hours later, the results were read as indicated in the manufacturers scheme, according to the following scale (): Class = <  CFU/ml saliva Class =  -  CFU/ml saliva Class =  -  CFU/ml saliva Class =>  CFU/ml saliva The statistic software programme StatsDirect (Stats-Direct version ..) was used in the analysis of the results.The prevalence of salivary Streptococcus mutans and Lactobacillus spp. in both groups of children was shown in percentages.T-test was applied in testing differences in the values of Streptococcus mutans and Lactobacillus spp. in respondents' groups.The value of p<, was taken as significant.

Results
Th e results showed no diff erences in the levels of salivary Lactobacillus spp. between the group of -year old children and the group of teenagers (p=,) (Table ).A significant difference exists between the group of -year old children and the group of teenagers in the levels of salivary Streptococcus mutans, where the teenagers have significantly higher values of Streptococcus mutans in the saliva (p= ,) (Table ).

Discussion
The  ): Th e results of our research show that the fi nding of the prevalence of salivary Streptococcus mutans in -year old children, whose dental status includes no active carious lesion, remains the same as that in their age-fellows selected by the method of random sample, where the dental status presented no criterion for participation in the study.In our research, twelve-year olds had no carious tooth, unlike the research of A. Zukanović, where the respondents had KEP-index ,, where caries component was ,, which means that each child in that participants' group had , carious teeth on average ().Comparing the values of Streptococcus mutans found in our children of various ages, we see that teenagers have signifi cantly higher values of salivary Streptococcus mutans.S. Bjarnason et alia () 20 made a longitudinal study that followed the levels of Streptococcus mutans, Lactobacillus spp.spp and KEP index through a three-   ).Th e above authors found the increase in the levels of examined microorganisms, in comparison with - years old children.When we compare these details with ours, we see a higher level of Streptococcus mutans in the group of our teenagers, too; however, when we compare the levels, we perceive a lower level of Streptococcus mutans, but much higher level of Lactobacillus spp. in our population, which can be explained with a higher consumption of carbohydrates and higher number of meals than in the Swedish population.Th e work of Steckens-Blicks reveals correlation between a higher consumption of carbohydrates and the levels of Streptococcus mutans and Lactobacillus spp.().
It has been proved that the number of Lactobacillus spp. in saliva depends on the type of food consumed during the day, and especially on the frequency of consumption of carbohydrates.Restricted consumption of carbohydrates brings to decline in the number of lactobacilli in saliva.Th erefore, recent practices of monitoring the dietary habits in humans and active participation of patients in preventive programs include measuring of the levels of Lactobacillus spp.. Hence, the level of Lactobacillus spp. in saliva indirectly points to the risk of the development of new carious lesion ().On the sample of  teenage participants, I.

Conclusion
Th e level of Streptococcus mutans in our children is higher in teenagers than in the younger children, while the diff erences in the level of Lactobacillus spp. in children of various ages do not exist.In view of the global distribution, the levels of Streptococcus mutans and Lactobacillus spp.are higher in our population than in other countries in both age groups concerned.Th e above data should be taken into consideration in the creating and implementing preventive programs for the improvement of oral health at all levels (individually, within families, schools, communities and similar).
 research by A. Zukanović about the prevalence of lactobacilli among -year old children in Sarajevo, conducted on a random sample of  children, showed that . children had very low values, , had low values, , high values, and , had very high values of salivary Lactobacillus spp.().The results of our research obtained similar results, where the level of salivary Lactobacillus spp.has the same distribution among -year old children and teenagers, and  of children have low and very low values of Lactobacillus spp.. Comparing the results obtained in children from Sarajevo with those obtained in their Sweedish age-fellows in the research by Hänsel-Petersson et al.(), we see that , -year old children in Sweeden have very low values, ,  low values, ,  have high values and ,  very high values of Lactobacilli in saliva.Th e study conducted among -year old children in Estonia shows that  children have very low values,  low,  high and  very high values of Lactobacilli ().Comparing the values of Lactobacilli in saliva among Sarajevo children with the above researches, we see that our children have higher levels of lactobacilli in saliva, which indicates a higher risk of the development of caries.The results of the research by A. Zukanović of  concerning the values of Streptococcus mutans in saliva among  -year old children in Sarajevo, selected by the method of random sample, prove that most -year old children have high values of Streptococcus mutans in saliva.In , of children we have very low, in , low, in , high, and in , very high values of Streptococcus mutans ().Th e following table displays the values of Streptococcus mutans in -year old children in several countries (Table

TABLE 1 .
Th e prevalence of Lactobacillus spp. in 12 years old children and teenagers

TABLE 2 .
Th e prevalence of Streptococcus mutans in 12 years old children and teenagers year period.Th rough their work we see that  of  years old participants have very high levels of Streptococcus mutans (  ), while  of participants have high level of Lactobacillus spp.( Zickert et al.  ()found Streptococcus mutans in  participants, among them  had very high levels thereof 22.Th e same authors also give details on the level of Lactobacillus spp. the presence of Lactobacillus spp. was found in  participants, among them  had high values.In our study,  of participants had the presence of Streptococcus mutans, among them , very high levels thereof, which is almost twice as much as in Swedish teenagers.Similar are the data on Lactobacillus spp., where the presence of lactobacilli was found in  of our teenagers, with  having high values thereof().Similar results were publicized by B.Kohler et  al. ()on the sample of  participants, Streptococcus mutans was isolated in  cases; among them, . had very high values().Lactobacillus spp.was found in  participants, where . had a high level thereof().Neither of the above authors gives explanation for the increased levels of Streptococcus mutans in children of older age.When it comes to the global distribution of salivary Streptococcus mutans, the research by authors El -Nadeef and Bratthall () is interesting.Th ey compared the values of Streptococcus mutans in children of various areas, which had diff erent levels of fl uoride in water.
duce caries risk to minimum.It should be noted that both the level of Streptococcus mutans and the level of Lactobacillus spp.present considerable risk-factors of caries, but whether and when caries would develop depends on many other factors as well, because caries is a complex infective condition of multi-causal etiology.

TABLE 3 .
Th e values of Streptococcus mutans in 12 years old children in diff erent countries: ENITA NAKAŠ, AMILA ZUKANOVIĆ: THE PREVALENCE OF CARIOGENIC SALIVARY MICRO-ORGANISMS IN CHILDREN OF VARIOUS AGES BOSNIAN JOURNAL OF BASIC MEDICALSCIENCES 2007; 7 (2): 168-172