The aim of the study was to find out if any of the following factors, alone or in combination, could be used for prediction of caries activity: salivarj' S. mulans, salivary lactobacilli, butler capacity, saliva secretion rate, salivary pH, the amount of plaque and the caries frequency. The patient material consisted of 300 children betvt^een 9 and 12 years old. The increment of caries after 1 and 2 years was compared widi all the above factors registered at baseline. Only the factors caries frequency and S. mutans showed a significant correlation to caries activity. In one of the tests the lactobacillus count approached significance. The combination of high numbers of incipient smooth surface lesions, S. mutans and lactobacilli gave a mean value of caries activity almost three times that of the whole group (8.4 versus 3,1). Different microbial ,and salivary factors review see 32). For selection of children at have been associated with the develop-high risk for caries the previous history of ment of caries. The microbial factors caries (caries frequency) has been used which have been studied most are the (2,14). numbers of Streptococcus mutans andIn the present study the increment of lactobacilli (for reviews see 7, 21). The cor-caries in schoolchildren has been corresponding salivary factors are the related with the above factors and the aim secretion rate, the pH and the buffer of the investigation was to find out if any capacity (for a review see 22). of the factors, alone or, in combination, The amount of plaque has also been registered once at the start of the study, associated with the caries process (for a was correlated to caries activity, i.e. the

– The prevalence of S. mutans and lactobacilli, the salivary secretion rate, and salivary pH and buffer capacity were examined in 655 children 9–12 years old. Some of these factors were correlated with the frequency of caries. Positive correlations were ob served between for example S. mutans and lactobacilli, between S. mutans and incipient smooth surface caries, and between lactobacilli and open carious lesion. A high proportion of the children showed large numbers of S. mutans and lactobacilli

Emilson CG, Klock B, Sanford GB. Microbial flora associated with presence of root surface caries in periodontally treated patients. Scand J Dent Res 1988; 96: 40-9.Abstract -Examination of saliva and dentai plaqtie was carried out in 35 adults who had been treated for periodontal disease 3 yr earlier. Plaque samples were collected from approximal and btiiccal sound and carions root surfaces. The satnples were analyzed for the presence and proportions of members of Streptococcus, Lactobacillus and Actinomyces. The results showed a low prevalence of root surface earies 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.

abstract— On the basis of the number of Streptococcus mutans and lactobacilli, 645 children 9–12 years old were divided into five groups. The children with the highest number of S. mutans and lactobacilli were considered to be at a high caries risk and were divided into three groups with 49 children in each. One group received preventive measures from a specially trained nurse twice a month, one group was treated once a month and the third group served as a control. The other 498 children with lower numbers of S. mutans and lactobacilli were considered to be at a lower caries risk and were divided into two groups. One group was treated once a month while the other was a control. The children with originally high numbers ofS. mutans and lactobacilli developed significantly more new carious lesions after 1 and 2 years (2.5 and 4.3) than the children with low counts in the control groups (1.9 and 2.8). All the children in the test groups which had received the preventive program developed significantly less caries than the corresponding control group. In the test risk group treated twice a month the caries activity was extremely low during the 1st year with an average of 0.34 new carious lesions. After 2 years the average was 0.92. The microbial conditions as well as the saliva secretion rate, buffer capacity and saliva pH did not seem to be influenced by the preventive program.

One hundred 14-yr-old children were observed over 1 yr to find out if caries incidence and caries progression could be predicted in a low prevalence child population by means of well-known caries related factors. The mean caries incidence was low (0.45, SD 0.70) but, on the other hand, 32% of the children developed at least one new lesion during the test period. In only eight out of 35 children progressing lesions were demonstrated. Independent variables at baseline examination were caries prevalence, sucrose intake, fluoride exposure, oral hygiene, saliva secretion rate, and salivary concentrations of mutans streptococci and lactobacilli. A weak but statistically significant correlation was demonstrated between caries incidence and caries prevalence. No other significant correlations were shown. It was concluded that caries activity could not be predicted in this population. Low disease prevalence was a major reason for the weak correlations.