Keiko Yamaki

Improvement of periodontal condition by probiotics with Lactobacillus salivarius WB21 : a randomized, double-blind, placebo-controlled study

AIM This randomized clinical study was designed to evaluate the effect of probiotic intervention using lactobacilli on the periodontal condition of volunteers without severe periodontitis. MATERIAL AND METHODS Freeze-dried Lactobacillus salivarius WB21 (WB21)-containing tablets or a placebo were given to volunteers in a double-blind randomized study. A total of 66 volunteers were finally enrolled and randomly assigned to receive tablets containing WB21 (6.7 x 10(8) CFU) with xylitol or xylitol alone (placebo) three times a day for 8 weeks. Periodontal clinical parameters and whole saliva samples were obtained at baseline (BL), 4 weeks, and the end of the interventional period (8 weeks). Salivary lactoferrin (Lf) levels were measured by enzyme-linked immunosorbent assay. Lactobacilli in saliva and plaque samples was detected by semi-quantitative RT-PCR using 16S rRNA primers. RESULTS Periodontal clinical parameters were improved in both groups after an 8-week intervention. Current smokers in the test group showed a significantly greater improvement of plaque index and probing pocket depth from BL when compared with those in the placebo group. Salivary Lf level was also significantly decreased in the test group smokers. CONCLUSION Our results indicate that probiotics could be useful in the improvement/maintenance of oral health in subjects at a high risk of periodontal disease.

Prevalence and risk factors for peri-implant diseases in Japanese adult dental patients

We investigated the prevalences and risk factors for peri-implant diseases in Japanese adult dental patients attending a follow-up visit at dental hospitals or clinics as part of their maintenance program. This cross-sectional multicenter study enrolled patients with dental implants who attended regular check-ups as part of a periodontal maintenance program during the period from October 2012 through September 2013. Patients with implants with at least 3 years of loading time were included in the study. The condition of peri-implant tissue was examined and classified into the following categories: healthy, peri-implant mucositis, and peri-implantitis. Patients were also evaluated for implant risk factors. A total of 267 patients (110 men, 157 women; mean age: 62.5 ± 10.7 years) were analyzed. The prevalence of patient-based peri-implant mucositis was 33.3% (n = 89), and the prevalence of peri-implantitis was 9.7% (n = 26). Poor oral hygiene and a history of periodontitis were strong risk factors for peri-implant disease. The present prevalences were lower than those previously reported. The quality of periodontal therapy before and after implant installation and patient compliance and motivation, as indicated by plaque control level, appear to be important in maintaining peri-implant tissue health.

Cultivable Anaerobic Microbiota of Infected Root Canals

Objective. Periapical periodontitis is an infectious and inflammatory disease of the periapical tissues caused by oral bacteria invading the root canal. In the present study, profiling of the microbiota in infected root canals was performed using anaerobic culture and molecular biological techniques for bacterial identification. Methods. Informed consent was obtained from all subjects (age ranges, 34–71 years). Nine infected root canals with periapical lesions from 7 subjects were included. Samples from infected root canals were collected, followed by anaerobic culture on CDC blood agar plates. After 7 days, colony forming units (CFU) were counted and isolated bacteria were identified by 16S rRNA gene sequencing. Results. The mean bacterial count (CFU) in root canals was (0.5 ± 1.1) × 106 (range 8.0 × 101–3.1 × 106), and anaerobic bacteria were predominant (89.8%). The predominant isolates were Olsenella (25.4%), Mogibacterium (17.7%), Pseudoramibacter (17.7%), Propionibacterium (11.9%) and Parvimonas (5.9%). Conclusion. The combination of anaerobic culture and molecular biological techniques makes it possible to analyze rapidly the microbiota in infected root canals. The overwhelming majority of the isolates from infected root canals were found to be anaerobic bacteria, suggesting that the environment in root canals is anaerobic and therefore support the growth of anaerobes.

Microflora profiling of infected root canal before and after treatment using culture-independent methods

This study aimed to profile the microflora in infected root canals before and after root canal treatment using culture-independent methods. Six infected root canals in single-rooted teeth with periapical lesions from five subjects were included. Quantification of total bacteria was performed by real-time PCR with primers targeting 16S rRNA genes. PCR products with universal 16S rRNA gene primers were cloned and partially sequenced, and bacterial identification at the species level was performed by comparative analysis with the GenBank database. The concentration of extracted DNA before treatment was higher than that after root canal treatment, although the difference was not statistically significant. Sequence analysis revealed that oral bacteria such as Fusobacterium, Streptococcus, Olsenella, and Pseudoramibacter detected in cases before root canal treatment disappeared after treatment. These results suggest that the root canal microflora are distinct before and after root canal treatment, and that treatment changes the microflora in both quantity and quality.

Oral Microbiota in Crevices Around Dental Implants: Profiling of Oral Biofilm

Large numbers of bacteria (>106/mm2) generally inhabit the surface of the oral cavity, particularly at the interface between teeth and gingiva, as an oral biofilm (microbiota). The establishment of anaerobic bacterial culture and molecular biological techniques has enabled us to isolate and detect various bacterial species from oral biofilm. It has been estimated that more than 600 bacterial species inhabit the oral cavity. Nevertheless, the oral cavity is considered healthy when the oral microbiota is composed of indigenous bacteria. Numerous environmental changes in the oral cavity may lead to accumulation of dental caries-associated or periodontitis-associated bacteria, resulting in the initiation of dental caries or periodontitis, respectively. The environment in crevices around dental implants is considered similar to that in subgingival sulcus, such as neutral pH, anaerobiosis and rich nutrition (e.g., amino acids and peptides). The environment may be supportive of anaerobic growth of the bacteria in microbiota in crevices around implants, particularly at the interface between histocompatible artificial material and mucosal epithelium. The microbiota may trigger inflammation in the tissue around the implants. In this article, the current topics on the profiling of oral microbiota in crevices around implants are reviewed.

Rapid Quantification of Bacteria in Infected Root Canals Using Fluorescence Reagents and a Membrane Filter: A Pilot Study on Its Clinical Application to the Evaluation of the Outcomes of Endodontic Treatment

Objective. The bacterial examination has been performed during the course of the root canal treatment. In the present pilot study, the new developed method, using fluorescence reagents and a membrane filter, was applied to the detection and quantification of bacteria in infected root canals, in order to evaluate the outcomes of the treatment. Methods. Six infected root canals with periapical lesions from 5 subjects were included. Informed consent was obtained from all subjects (age ranges, 23–79 years). Samples from infected root canals were collected at the beginning of the treatment (termed #25 First), the end of the first day of treatment (termed #55 First), and the next appointment day (termed #55 Second). Then, the bacterial count (CFU) was measured using fluorescence reagents (4′,6′-diamidino-2-phenylindole and propidium iodide) and the polycarbonate membrane filter by Bioplorer. Results. The mean ± SD of CFU in the sample of “#25 First” was (1.0 ± 1.4) × 105. As the root canal treatment progressed, the CFU decreased as 7.9 × 103 (#55 First) and 4.3 × 102 (#55 Second). Conclusion. In the present pilot study, rapid detection and quantification of bacteria in infected root canals were found to be successfully performed using fluorescence reagents and a membrane filter (Bioplorer analysis).

Change in Infected Root Canal Microflora During the Course of Root Canal Therapy

The purpose of the present study was to profile the microflora in infected root canals, using anaerobic culture and molecular biological techniques for bacterial identification, before and after root canal treatment. The mean bacterial count in root canals before treatment was 106, and obligate anaerobes were predominant. The predominant isolates were Olsenella, Pseudoramibacter, Propionibacterium and Mogibacterium. On second and third visits, no bacteria were detected in the samples collected after treatment. These results suggest that the environment in root canals is anaerobic and therefore support the growth of anaerobes, and that adequate treatment changes the root canal environment drastically.

Microflora profiling of root canal utilizing real-time PCR and cloning-sequence analyses based on 16S rRNA genes—differences between before and after root canal treatments

This study aimed to profile microflora of root canals before and after root canal treatments, using real-time PCR and cloning-sequence analyses based on 16S rRNA genes. Six infected root canals of single-rooted teeth with periapical lesions were included. The quantification of total bacteria was performed by realtime PCR using universal primers based on 16S rRNA genes. PCR products were cloned and partially sequenced, and bacterial identification to the species level was performed by comparative analysis with the GenBank database. The concentrations of bacterial DNA after root canal treatments were less than those before root canal treatments. The cloning-sequence analysis suggested that the root canal microflora in cases of after root canal treatments was clearly distinct from that of before root canal treatments.

Effects of orally administered Lactobacillus salivarius WB21 supplement on periodontal clinical parameters and microflora

The aim of this study was to evaluate whether the oral administration of lactobacilli could change the periodontal condition and microflora compared with placebo. Sixty-six healthy volunteers were randomized into two groups to receive lactobacilli or placebo for 8 weeks. The mean Plaque Index, Gingival Index, and bleeding on probing were significantly improved at 4 and 8 weeks in both groups, but showed the biggest change on smokers in the test group. Occurrence of Porphyromonas gingivalis and Treponema denticola in the subgingival plaque sample significantly decreased in the test group at 8 weeks. Oral administration of probiotic lactobacilli successfully reduced the prevalence of periodontopathic bacteria from the subgingival plaque, and possibly contributed to the beneficial effects on periodontal conditions.