Mutans streptococci, lactobacilli and caries prevalence in 11-and 12-year-old Icelandic children

Since the caries prevalence has not declined in Iceland as it has in other European countries, it was of interest to study the presence of cariogenic bacteria in Icelandic children. The prevalence of salivary mutans streptococci and lactobacilli was examined in 217 11- and 12-yr-old Icelandic children and was related to their caries prevalence. In 2% of the children mutans streptococci were not found whereas 31% and 35% of the 11-yr-olds and 12-yr-olds respectively carried more than 10(6) CFU per ml saliva. Lactobacilli were not detected in 8% of the children whereas 28% of the 11-yr-olds and 23% of the 12-yr-olds had more than 10(5) CFU per ml saliva. The mean caries prevalence (DFS), initial caries included, for 11-yr-olds was 21.6 and for 12-yr-olds 28.8. Both mutans streptococci and lactobacilli were significantly correlated to each other as well as to caries prevalence. An increased number of these microorganisms, especially the mutans streptococci, were associated with an increased DFS. Children with high salivary counts of mutans streptococci and lactobacilli showed four times higher DFS than children with low numbers. The magnitude of salivary cariogenic bacteria as well as caries prevalence was found to resemble the situation in Sweden 10 yr ago. S. mutans (serotype c/e/f) was carried by all mutans streptococci positive children. S. sobrinus (serotype d/g) was found in 60 children (30.2%). Children with both S. mutans and S. sobrinus had significantly higher salivary counts of mutans streptococci and lactobacilli as well as caries prevalence than children with only S. mutans.     

Salivary levels of mutans streptococci, lactobacilli, yeasts, and root caries prevalence in non-institutionalized elderly dental patients

Root caries prevalence was recorded for a consecutive sample of dental patients (n = 146), aged over 55 yr and with at least 12 natural teeth. The mean root DFS score of the males (n = 49) was 6.34 +/- 4.55 and for the females (n = 97) 3.76 +/- 3.31 (P less than 0.001). The salivary levels of mutans streptococci, lactobacilli, and yeasts were determined in addition to salivary flow rate and buffering capacity. Subjects with greater than 1 root DFS had significantly higher salivary levels of mutans streptococci, lactobacilli, and yeasts. They also had fewer teeth and more exposed root surfaces. In step-wise multivariate analyses the factors significantly related to the root DFS score were the number of exposed root surfaces, number of teeth, sex and salivary yeast levels (R2 = 0.41). In the multivariate analyses salivary levels of mutans streptococci were not significantly related to any clinical measurement of root caries experience due to the greater strength of association between the root DFS score and salivary levels of yeasts. Subjects prescribed medicines with a reported xerostomic effect had significantly fewer active root lesions than those not prescribed such medicines and salivary levels of all microorganisms studied were significantly elevated in subjects prescribed medications containing sucrose.     

Root surface caries and associated factors

Abstract – The prevalence of root surfaces caries in 208 randomly selected 55, 65, and 75-yr-old Swedes was related to the frequency of coronal caries, the number of remaining teeth and to bacteriologic, salivary, and dietary variables. At least one decayed or filled root surface was found in 89% of the individuals and all of those had also experienced coronal caries. The frequency of root surface caries was positively correlated to the frequency of coronal decay and negatively correlated to the number of remaining teeth and exposed root surfaces. The study shows that the same factors which are associated with enamel caries seem to be of importance in determining the development of root surface caries. The variation in the frequency of root surface caries was best explained by the salivary levels of mutans streptococci and lactobacilli, the percentage of surfaces harboring plaque and the frequency of carbohydrate intake. Other contributory factors were the saliva secretion rate and the buffer capacity.     

Relationship of microbial and salivary parameters with dental caries in Brazilian pre-school children

Caries examination and collection of paraffin wax-stimulated saliva samples were performed in 37 children, 3-6 years old, in a child-care facility at the Vidigal slum, Rio de Janeiro, Brazil. The levels of mutans streptococci and lactobacilli in saliva were estimated by the Cariescreen and by the Dentocult tests and the saliva secretion rate was determined. Statistical analysis was performed on surface-based and patient-based caries prevalence rates (SBCPR and PBCPR), and related to bacterial and salivary parameters. The results show that 31 of the 37 children were caries active. The SBCPR for the primary dentition was 6.7% +/- 1.0%. Occlusal surfaces were the most affected by decay. Regression analysis revealed that mutans streptococci salivary levels were significantly associated with the SBCPR (P = 0.0001). Similarly, lactobacilli salivary levels were significantly associated with the SBCPR (P = 0.0001). No significant association could be found between the saliva secretion rate and the SBCPR. When regression analysis was used to model dependence of the SBCPR on both organisms, the mutans streptococci and lactobacilli salivary levels were significantly associated with the SBCPRs (P = 0.0021 and 0.0118, respectively), and salivary levels of these organisms accounted for 57% of the SBCPR variability. These findings indicate that the levels of mutans streptococci and lactobacilli in saliva are significantly related to the SBCPRs on the primary dentition of these children.     

Salivary conditions and cariogenic microorganisms in 55, 65, and 75-year-old Swedish individuals

Secretion rate, buffer capacity, and cariogenic microorganisms of resting and stimulated whole saliva were examined in 208 55-, 65-, and 75-yr-old Swedes. The secretion rate for both resting and stimulated saliva decreased with age. When the use of drugs was taken into account the difference in terms of age group was significant for resting saliva alone (P less than 0.01). In 22% the resting saliva was less than 0.1 ml/min, and in 5% the stimulated saliva was less than 0.7 ml/min. Persons with subjective dryness in the mouth had a lower salivary flow. Men had higher secretion rates than women irrespective of medication (P less than 0.05). The buffer capacity was strongly correlated to the secretion rate of both resting and stimulated saliva (r = 0.39 and r = 0.44, respectively). The number of mutans streptococci and lactobacilli increased with age, although significant in terms of age group for lactobacilli alone (P less than 0.05). The number of these microorganisms was lower in resting saliva than in stimulated saliva (P less than 0.0001). Individuals harboring both Streptococcus mutans and Streptococcus sobrinus had higher values of mutans streptococci in resting and stimulated saliva than those harboring only S. mutans (P less than 0.001). Actinomyces viscosus and Actinomyces naeslundii comprised greater than or equal to 1% of the total CFU in 89% of the plaque samples. The corresponding figures for lactobacilli and mutans streptococci were 6% and 38%, respectively.     

Association of the microbial flora of dental plaque and saliva with human root-surface caries

Dental plaque was obtained from one or two sound root surfaces of subjects with different degrees of root-surface caries experience. From subjects with root-surface caries, plaque samples were also obtained from either one incipient or one more advanced lesion. Proportions of the total flora were determined for total streptococci and different streptococcal species, total and different Actinomyces species, and lactobacilli. A sample of saliva was obtained from about one-third of the subjects for determination of the concentrations of mutans streptococci and lactobacilli. The main observations were: (1) Subjects without root-surface caries or restorations (group I), as compared with subjects with root-surface caries with or without restorations (group II), were characterized by having a lower prevalence and proportion of mutans streptococci and a higher prevalence and proportion of A. naeslundii in plaque on sound root surfaces; (2) subjects in group I also tended to have a lower salivary concentration of mutans streptococci and lactobacilli than subjects in group II; (3) dental plaque on sound surfaces in group II subjects contained a lower proportion of mutans streptococci than plaque associated with incipient or advanced lesions; and (4) the prevalence and proportion of lactobacilli in plaque associated with sound as well as carious root surfaces were very low. The data reinforce findings from other studies and indicate that, as for coronal caries, the plaque and saliva populations of mutans streptococci specifically are correlated positively with the presence of root-surface caries.     

Salivary caries-related tests as predictors of future caries increment in teenagers. A three-year longitudinal study

The aim of the study was to evaluate the capability of caries-related salivary tests and a test based on past caries experience (baseline DFS) to select persons at high risk for caries. The subjects (n = 122) were 12-17 years old at the beginning of the study. Caries was registered and salivary samples were taken annually during the 3-study period. The 3-year caries increment was positively correlated to the baseline DFS (r = 0.46, p less than 0.001), salivary level of mutans streptococci (r = 0.30, p less than 0.001) and lactobacilli (r = 0.30, p less than 0.001), and combined level of mutans streptococci and lactobacilli (r = 0.39, p less than 0.001) and negatively correlated to the buffering capacity of saliva (r = -0.22, p less than 0.05). Tests based on either past caries experience or mutans streptococci or lactobacilli levels alone were not efficient in selecting persons at high risk for caries. Among the tests, DFS was the most sensitive and specific. A combination of either microbial test and DFS was more efficient to select persons at risk than various alternatives alone. The sensitivity was 84% and the specificity 62% for the combination of lactobacilli test and DFS and 71% and 79% respectively for the combination of mutans streptococci and DFS. In the former combination the positive prediction value was 43% and in the latter 56%.     

Microbial flora associated with presence of root surface caries in periodontally treated patients

Abstract — Examination of saliva and dental plaque was carried out in 35 adults who had been treated for periodontal disease 3 yr earlier. Plaque samples were collected from approximal and buccal sound and carious root surfaces. The samples were analyzed for the presence and proportions of members of Streptococcus, Lactobacillus and Actinomyces. The results showed a low prevalence of root surface caries and a low level of salivary mutans streptococci and lactobacilli. From subjects with root caries there was a not statistically significant tendency to higher proportional levels of mutans streptococci in plaque from carious root surfaces than from caries-free surfaces. An inverse significant relationship between noncarious and carious root surfaces was noted for S. sanguis. The population of A. viscosus and A. naeslundii was similar in plaque samples from sound and carious sites but showed elevated levels in the subjects with five or more new root surface lesions.     

Saliva, salivary micro-organisms, and oral health in the home-dwelling old elderly--a five-year longitudinal study.

High scores of chair-side salivary microbial tests have been found to be related to an increased prevalence and incidence of coronal and root caries. Many elderly face an increased risk of the growth of oral microbes, and previous studies have reported high salivary microbial counts in elderly populations. The aim of this follow-up study was to compare, at five-year intervals, stimulated salivary flow rates with the numbers of selected salivary micro-organisms (mutans streptococci, lactobacilli, and yeasts) in a group of home-dwelling elderly in Helsinki. A further aim was to study the influence of baseline microbial counts on five-year root caries increments and rates of tooth loss. The baseline study population was comprised of 270 subjects who were all participants in the population-based Helsinki Aging Study. Salivary flow rates and microbial conditions were determined as part of their dental examination at the Institute of Dentistry, University of Helsinki, in 1990-1991. Of these subjects, 110 underwent a follow-up examination in 1995-1996. Commercially available kits (Dentocult SM strip mutans for mutans streptococci, Dentocult LB for lactobacilli, and Oricult N for yeasts) were used for the enumeration of micro-organisms, after the collection of paraffin-wax-stimulated whole saliva. The stimulated whole saliva flow rates of the subjects were significantly lower at the follow-up than at baseline (paired t test, difference -0.16 mL/min; p < 0.05), whereas buffer capacity was higher (paired t test, difference 0.19 on a three-unit scale; p < 0.05). Apart from lower salivary lactobacilli counts at follow-up (paired t test, difference -0.44 CFUs/mL of saliva; p < 0.001), no changes were found in salivary microbial levels. Salivary microbial counts were clearly associated with the subjects' dentition types: More denture-wearers had high microbial counts than persons with natural dentitions. None of the salivary factors correlated with the root caries incidence or the number of teeth lost during the five-year follow-up.     

Root surface and coronal caries in adults with type 2 diabetes mellitus

OBJECTIVES: To determine the effect of type 2 diabetes mellitus (DM) on coronal and root surface caries and to investigate some factors suspected of being related to or interacting with DM, that may be associated with coronal and root surface caries. METHODS: A stratified cross-sectional study was conducted in 105 type 2 diabetic patients and 103 non-diabetic subjects of the same age and gender. Coronal and root surface caries, exposed root surfaces, periodontal status, stimulated salivary functions, oral hygiene status, oral health behaviors, and counts of mutans streptococci and lactobacilli were measured. RESULTS: Type 2 diabetic patients compared with non-diabetic subjects had a higher prevalence of root surface caries (40.0% versus 18.5%; P = 0.001), a higher number of decayed/filled root surfaces (1.2 +/- 0.2 versus 0.5 +/- 0.1; P < 0.01) and a higher percentage of generalized periodontitis (98.1% versus 87.4%; P < 0.01); but the prevalence and decayed/filled surface of coronal caries was not significantly different (83.8% versus 72.8% and 8.0 +/- 9.4 versus 6.3 +/- 7.5 respectively). The factors associated with root surface caries included type 2 DM, a low saliva buffer capacity, more missing teeth, and existing coronal caries; whereas wearing removable dentures, more missing teeth, a high number of lactobacilli, and a low saliva buffer capacity were associated with coronal caries. CONCLUSION: Type 2 DM is a significant risk factor for root surface, but not for coronal caries. Periodontal disease should be treated early in type 2 diabetic subjects to reduce the risk of subsequent root surface caries.     

Streptococcus mutans, Iactobacilli, and caries experience in older adults

This study Investigated salivary levels of Streptococcus mutans, lactobacilli, and caries experience in a random sample of 448 black and 362 white older dentate adults living in North Carolina. Significant proportions of the participants had stimulated salivary flow rates less than 1.0 mL/min, salivary buffering capacity less than 4.0, S. mutans levels of 10⁵ cfu/mL or more in stimulated whole saliva, or lactobacilli levels of 10⁵ cfu/mL or more. Each of these factor levels could be considered, on a clinical basis, to increase caries risk. in general, people with higher levels of S. mutans or lactobacilli had more untreated coronal and root caries, but not greater total caries experience.     

Mutans streptococci, lactobacilli and caries prevalence in 15 to 16-year olds in G?teborg. Part II.

During the fall of 1987 one hundred and fifty-five 15 to 16-year-olds were examined with regard to caries prevalence, saliva secretion rate and salivary numbers of mutans streptococci and lactobacilli. In 15% of the subjects no mutans streptococci were detected, while 17.7% carried > 10(6) colony forming units (cfu) per ml saliva. The median value was 1.8 x 10(5) cfu per ml saliva. No lactobacilli were detected in 19% of the subjects and 14.3% had > 10(5) cfu per ml saliva. The mean caries prevalence was 21.0, of these 14.1 were incipient lesions. Increased numbers of mutans streptococci and lactobacilli were associated with increasing caries prevalence. Subjects with high numbers of both microorganisms showed about 4 times higher mean caries prevalence than those with low numbers. Streptococcus sobrinus carriers (15%) had both higher mean caries prevalence and a higher proportion of subjects with > 10(6) cfu mutans streptococci per ml saliva than was found in the whole group.     

Root surface caries and associated factors

The prevalence of root surfaces caries in 208 randomly selected 55, 65, and 75-yr-old Swedes was related to the frequency of coronal caries, the number of remaining teeth and to bacteriologic, salivary, and dietary variables. At least one decayed or filled root surface was found in 89% of the individuals and all of those had also experienced coronal caries. The frequency of root surface caries was positively correlated to the frequency of coronal decay and negatively correlated to the number of remaining teeth and exposed root surfaces. The study shows that the same factors which are associated with enamel caries seem to be of importance in determining the development of root surface caries. The variation in the frequency of root surface caries was best explained by the salivary levels of mutans streptococci and lactobacilli, the percentage of surfaces harboring plaque and the frequency of carbohydrate intake. Other contributory factors were the saliva secretion rate and the buffer capacity.     

The earlier the colonization by mutans streptococci, the higher the caries prevalence at 4 years of age

Seventy-eight 4-year-old children, examined earlier for the presence of mutans streptococci at 4-month intervals from 15 months of age, were recalled for recording of dental caries and salivary sampling. The saliva samples were analysed for the presence of mutans streptococci, including the species Streptococcus mutans and Streptococcus sobrinus and lactobacilli. The results showed that the earlier the mutans streptococci had been detected in the children, the higher the caries experience. Eighty-nine percent of the children colonized at 2 years of age had experienced caries and had a mean dfs of 5.0 compared with 25% of the non-colonized 4-year-olds with a mean dfs of 0.3. S. mutans was the predominant species. S. sobrinus was usually found in combination with S. mutans , except in 2 children where S. sobrinus was the only species detected. More children with multiple species had higher numbers of total mutans streptococci and a tendency to higher caries prevalence than children with only S. mutans.     

Dental caries and salivary and microbial conditions in 50–60-year-old persons

In a group of 124 persons, 50-60 yr old, the prevalence at baseline of mutans streptococci (MS) and lactobacilli and the salivary secretion rate and buffer capacity were examined. The mean secretion rate was 1.58 mL/min with a flow rate below 1 mL/min found in 20% of the persons. A buffer capacity below end pH 5.5 was observed in 64% of the subjects. MS was not detected in 5% of the persons whereas 17% had 10(6) or more MS per ml saliva. Lactobacilli were not found in 10% of the persons while 21% had counts in excess of 10(5) CFU mL. A new examination 5 yr later in 1986 revealed no significant changes in secretion rate and buffer capacity or in the population of lactobacilli, whereas markedly elevated levels of salivary MS were found. S. sobrinus was detected in 35-37% of the persons at the two examinations. Persons with both S. mutans and S. sobrinus had more MS than persons with only S. mutans.     

Mutans streptococci and lactobacilli in saliva from children with insulin-dependent diabetes mellitus

The quantitative distribution of mutans streptococci and lactobacilli in saliva of insulin-dependent diabetic children was compared with a group of healthy children and related to the metabolic control of the disease. The study group, consisting of 94 boys and girls (age 4-19) with type 1 diabetes was matched by sex and age with a non-diabetic control group. Stimulated whole saliva was collected and flow rate, buffer capacity and the levels of mutans streptococci and lactobacilli were analysed in all children. In the diabetic group, total salivary proteins and glucose content of saliva were determined. Data on caries experience were recorded from the dental cards of all children. There were no difference in the distribution or number of mutans streptococci between the groups, but significantly (p less than 0.05) lower levels of lactobacilli were found among the diabetic children. The number of lactobacilli was positively correlated (p less than 0.05) to glucose concentration in saliva. There was no difference in the prevalence of caries between the groups. The present findings suggest that the dietary treatment of young insulin dependent diabetics gives rise to a reduced number of lactobacilli in saliva but does not affect the mutans streptococci.     

Salivary conditions and cariogenic microorganisms in 55, 65, and 75-year-old Swedish individuals

Abstract – Secretion rate, buffer capacity, and cariogenic microorganisms of resting and stimulated whole saliva were examined in 208 55-, 65-, and 75-yr-old Swedes. The secretion rate for both resting and stimulated saliva decreased with age. When the use of drugs was taken into account the difference in terms of age group was significant for resting saliva alone (P<0.01). In 22%, the resting saliva was <0.1 ml/min, and in 5% the stimulated saliva was <0.7 ml/min. Persons with subjective dryness in the mouth had a lower salivary flow. Men had higher secretion rates than women irrespective of medication (P<0.05). The buffer capacity was strongly correlated to the secretion rate of both resting and stimulated saliva (r=0.39 and r=0.44, respectively). The number of mutans streptococci and lactobacilli increased with age, although significant in terms of age group for lactobacilli alone (P<0.05). The number of these microorganisms was lower in resting saliva than in stimulated saliva (P<0.0001). Individuals harboring both Streptococcus mutans and Streptococcus sobrinus had higher values of mutans streptococci in resting and stimulated saliva than those harboring only S. mutans (P<0.001). Actinomyces viscosus and Actinomyces naeslundii comprised 1% of the total CFU in 89% of the plaque samples. The corresponding figures for lactobacilli and mutans streptococci were 6% and 38%, respectively.     

Salivary levels of mutans streptococci and lactobacilli in dentate 80- and 85-year-old Swedish men and women

The number of Streptococcus mutans, Streptococcus sobrinus, and lactobacilli in whole stimulated saliva was examined in 130 dentate 80- and 85-yr-old persons. 88.5% were positive for mutans streptococci and 29% carried greater than 10(6) cfu per ml saliva. S. mutans was most frequently isolated and was found in 114 persons (88%) alone or in combination with S. sobrinus. S. sobrinus was detected in 33 persons (25%), who also showed significantly higher salivary numbers of both mutans streptococci and lactobacilli than persons from whom S. sobrinus was not isolated. The S. sobrinus carriers also had significantly lower stimulated saliva secretion rates than the non-carriers. 95% of the subjects had detectable levels of lactobacilli in saliva with 35% having greater than 10(5) cfu per ml saliva. When the subjects were divided into classes according to the number of intermaxillary contacts, i.e. the Eichner classification, the distribution of subjects with high and low salivary counts of cariogenic bacteria varied. Thus fewer subjects belonging to Eichner class A showed higher salivary numbers of mutans streptococci (14% had greater than 10(6) cfu/ml) as well as lactobacilli (21% had greater than 10(5) cfu/ml) than, for example, subjects belonging to Eichner class B (26% had greater than 10(6) cfu/ml of mutans streptococci, 35% had greater than 10(5) cfu/ml of lactobacilli). Subjects who carried a removable denture(s) had significantly higher salivary numbers of both mutans streptococci and lactobacilli than subjects without removable dentures.     

A cross-sectional study into the prevalence of root caries in periodontal maintenance patients

Abstract. The aim of this cross-sectional study was to investigate cross-sectionally the prevalence and several risk indicators of root caries in 45 periodontal maintenance patients, who had been actively treated for adult periodontitis 11–22 years ago. These patients were part of a routine 3–6 monthly maintenance schedule. Active and inactive root caries and root fillings were recorded, as well as coronal caries experience. Plaque and bleeding scores, number of exposed root surfaces, rate of saliva secretion, saliva buffering capacity, mutans streptococci counts and Lactobacilli were also scored. From the total of 45 study subjects, 37 patients (82%) showed root lesions (root caries and/or root fillings), while only 8 patients were free of any root lesions. On average, there were 4.3 root lesions per patient (range 0–19) in the present study. 10 patients had active root caries lesions. Of all damaged root surfaces, 9% were active lesions, mostly located on mandibular teeth at lingual and vestibulair sites; 40% were inactive lesions often detected at vestibular sites. The remaining damaged root surfaces (51%) were restored; they were equally divided over both jaws. A higher number of root lesions was observed in those patients with >10⁶mutans streptococci/ ml saliva. Although the actual number of lesions per patient was low in relation to the large number of sites with gingival recession, the results from this cross-sectional study in periodontal maintenance patients indicate that: (1) root caries can be regarded as a complication in periodontal maintenance patients; (2) the individual number of root lesions correlate with individual dental plaque scores; (3) a high number of root lesions is associated with high counts of salivary mutans streptococci; (4) no relation between root caries and coronal caries experience, salivary secretion rate or salivary buffering capacity seems present. Therefore, repeated oral hygiene instructions and adjunctive preventive measures including diet counseling and fluoride rinses, as well as fluoride and chlorhexidine varnishes, should be advocated in high-risk patients.     

Associations of microbiological factors and plaque index with caries prevalence and water fluoridation status

Plaque indices, numbers of mutans streptococci, lactobacilli and total viable flora in plaque and saliva were assessed as part of a large-scale cross-sectional study designed to determine the factors that are associated with high caries activity in children. Subjects, 12 to 15 years old, residing in areas where the water supplies were either fluoridated (n = 140) or fluoride-deficient (n = 173) were studied. Mutans streptococci and lactobacilli numbers in saliva were positively correlated with plaque index. Plaque indices were significantly higher in the high-caries group than in the zero-caries group of the fluoride-deficient community. In the fluoridated community, there was no difference in the plaque index between the zero- or high-caries groups. In each community, pooled dental plaque and saliva harbored fewer mutans streptococci and lactobacilli in the zero-caries than the high-caries group. Greater numbers of mutans streptococci were found in the dental plaque and saliva of the zero-caries subjects in the fluoridated community than in the fluoride-deficient community, suggesting that a greater caries challenge can coexist with zero-caries status in the fluoridated community.