The overall implant failure rate in a population treated and maintained for periodontal disease is similar to that of healthy subjects. A synergistic effect found between smoking and a positive IL-1 genotype resulted in a significantly higher implant loss. This indicates that further research with a larger patient group should focus on multifactorial analysis for adequate risk assessment.

The aim of this study was to clarify the distribution and persistence of mutans streptococci on different tooth sites in the same oral cavity. Thirteen subjects, aged 20-40 years, were examined. Salivary levels of mutans streptococci, caries prevalence, oral hygiene habits and status of tooth surfaces sampled were recorded. Plaque samples were obtained from four sites, the mesial and buccal surfaces of the first permanent molar on the right side of the lower jaw (46m and 46b), the distal surface of the first permanent premolar (24d) and the mesial surface of the second permanent premolar (25m) on the left side of the upper jaw, using sterile toothpicks on two occasions at 4-7-month intervals. The samples were cultivated on site-specific Strip mutans. Up to 10 colonies/site were isolated when present and genotyped by random amplified polymorphic DNA (RAPD) analysis, after species identification with PCR. Genotyping was also performed by restriction endonuclease analysis (REA) on 148 isolates, and results were consistent with the RAPD results. Most mutans streptococcus-positive samples were obtained from 46m. Within each individual, the same genotype occurred on at least two sites on all but one sampling occasion. A maximum of seven different genotypes were found in an individual. For a particular tooth site, four genotypes occurred simultaneously and taking both sampling occasions together the maximum was six different types. The same genotypes/types were found again after 4-7 months on 25 sites in 12 subjects. Fifteen sites were mutans streptococcus-positive on only one sampling occasion. The results indicate that several different genotypes of mutans streptococci colonize a tooth site, and that the same genotype colonizes several sites in the same oral cavity. Persistence of genotypes on a site for several months and interindividual differences in the occurrence of genotypes were also found.

The aim of this study, performed in Bangkok, was to study whether a particular salivary immunoglobulin A (IgA) antibody profile against mutans streptococci could be related to the absence or presence of caries. A group of 12-year-old individuals representing various combinations of mutans streptococci levels and caries experience was selected. Whole saliva stimulated by paraffin-chewing was collected, and the children were investigated for decayed, missing and filled surfaces (DMFS) and teeth (DMFT), following WHO criteria and methods, at baseline and after 2 years. The total amount of salivary IgA was determined by an immunobead enzyme-linked immunosorbent assay, and SDS-PAGE and Western blot analysis was performed using sonicated antigens of Streptococcus mutans and Streptococcus sobrinus strains and, as a control, a Streptococcus parasanguis strain. The results showed that Thai children with low caries prevalence had more distinct immunoblot bands to antigens from mutans streptococci than did the high-caries children. A similar picture was not seen for S. parasanguis. On the whole, the Thai children also showed fewer bands than usual Swedish saliva samples from comparable age groups. The complexity of the relationship between dental caries and IgA in saliva is highlighted.

Objective. To clarify the effect of Lactobacillus plantarum 299v on the salivary cortisol and salivary IgA levels in young adults under examination stress. Design. Forty-one students with an upcoming academic exam were included in a randomized double-blind, placebo-controlled study. The probiotic bacteria or the placebo product was administered in capsules once a day during 14 days. Saliva was collected and a perceived stress test was filled out at each sampling occasion. Saliva was collected for cortisol analysis by Electrochemiluminescence Immunoassay (ECLI) and salivary IgA was analysed by Enzyme-Linked Immunosorbent Assay (ELISA). Abundance of lactobacilli was evaluated by cultivation of saliva on selective medium and identification of L. plantarum 299v was done on randomly selected colonies by a random amplification of polymorphic DNA (RAPD) typing. Results. A significant difference in cortisol levels was found between the treatment group and the placebo group (P < 0.05), together with a significant increase in levels of lactobacilli in the treatment group compared with the placebo group (P < 0.001). No significant changes were found for salivary IgA. Conclusion. A probiotic bacterium with ability to reduce symptoms of irritable bowel syndrome (IBS) prohibited increased levels of the stress marker cortisol during the examination period. The registration number of the study is NCT02974894, and the study is registered at ClinicalTrials.gov.

According to previous studies, minor glands produce about 35% of the total salivary immunoglobulin A (salivary IgA). The age-dependent increase in whole-saliva salivary IgA concentrations has been studied extensively, but we found no published reports comparing the minor-gland saliva concentrations of salivary IgA in children, adolescents, and adults. In this study we measured the concentration of salivary IgA in saliva from the labial and the buccal minor glands of children, adolescents, and adults. Three age groups donated saliva for analysis: 3-yr-old children, 14-yr-old adolescents, and 20- to 25-yr-old adults. Minor-gland saliva was collected on filter paper and unstimulated whole saliva was collected by draining into a tube, and the salivary IgA concentration was determined by ELISA. The salivary IgA concentration in labial saliva was significantly lower among 3-yr-old children (0.037 mg 100 ml(-1), SD = 0.035) than among 14-yr-old adolescents (0.126 mg 100 ml(-1), SD = 0.128) and adults (0.128 mg 100 ml(-1), SD = 0.13). The 3-yr-old children also had significantly lower whole-saliva salivary IgA values compared with the other age groups (0.09 mg 100 ml(-1), SD = 0.091; 0.179 mg 100 ml(-1), SD = 0.149; and 0.170 mg 100 ml(-1), SD = 0.099, respectively). This increase in salivary IgA concentrations with age might reflect a developing immune response in the growing child.

Supplementation with two strains of the probiotic L. reuteri did not affect sIgA or cytokine levels in whole saliva in healthy young adults. The results thereby indicate that daily oral supplementation with L. reuteri do not seem to modulate the salivary oral immune response in healthy young subjects (ClinicalTrials.gov NCT02017886).

We investigated whether ingestion of probiotic bacteria could influence salivary IgA levels, specific anti-mutans streptococci IgA levels and specific antibodies towards the ingested probiotic bacterium. The study was a randomised, double-blind, placebo-controlled trial, where the test group (n = 11) received twice daily chewing of gum containing Lactobacillus reuteri (2 × 10(8)  CFU per dose) and the control group (n = 12) received placebo. Resting saliva was collected before and after 12 weeks of treatment and 4 weeks after end of treatment. Total salivary IgA concentrations were measured by ELISA. Specific IgA reactivity was determined using a whole-cell ELISA. Results were expressed as % IgA per protein in saliva. The level of total IgA% per protein increased significantly between pretreatment levels (13.5%) and follow-up treatment levels (14.4%) within the test group only (P < 0.05). No changes were seen in the control group during the trial. The level of probiotic-reactive antibodies decreased significantly between pre- and post-treatment samples (from 12.2% to 9.0%, P < 0.05) in the test group. Similarly, the level of specific mutans streptococci antibodies decreased significantly between pre- and post-treatment samples (P < 0.05) in the test group only (for Streptococcus mutans from 20.1% to 15.0%; for Streptococcus sobrinus from 7.4% to 5.3%). Ingestion of probiotic bacteria might influence the adaptive immune response of the host.

Antigen extracts of 9 strains of Streptococcus mutans, Streptococcus sobrinus, Streptococcus salivarius and Streptococcus mitis were separated in acrylamide gels by electrophoresis. Strains of the same genotype of mutans streptococci were found to have virtually identical sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns but differed clearly from other genotypes of mutans or with the reference strains S. salivarius and S. mitis. Immunoglobulin A (IgA) antibody activity to antigens of S. mutans, S. sobrinus and S. mitis in the parotid, submandibular and whole saliva of 12 people was detected by Western blotting. IgA antibodies reacted with several of the antigens, and the reaction pattern was unique for each of the individuals. To certain antigens, all the salivas blotted bands if both clear and questionable bands were counted. Significantly more blotted bands were revealed with antigens from S. mutans than S. sobrinus. The results of the 3 different salivas of the same individual had a high degree of resemblance but in a few individuals, more blotted bands were obtained with parotid saliva to S. mutans and S. sobrinus antigens.