Smoking habit modulates peri-implant microbiome: A case-control study.

BACKGROUND AND OBJECTIVE: Smoking is a recognized risk factor for peri-implant disease and leads to microbiological changes in mucositis and peri-implantitis. However, there is no knowledge about the impact of smoking in healthy peri-implant tissue. The aim of the study was to evaluate the microbiome in a peri-implant environment in smokers with healthy peri-implant conditions. METHODS: Peri-implant biofilm was collected around single clinically healthy, screwed-retained, teeth-surrounded implants in 12 non-smoker (NSMK) and 12 smoker (SMK) non-periodontitis subjects (no bleeding and probing depth <4 mm). Bacterial DNA was isolated and 16S ribosomal RNA gene libraries were sequenced using pyrosequencing, targeting the V3-V4 region. Datasets were processed using the Quantitative Insights into Microbial Ecology, Greengenes and the Human Oral Microbiome Database databases. RESULTS: An evident difference in the SMK peri-implant microbiome was observed compared to the NSMK microbiome, with a large abundance of species, even with a healthy peri-implant. The SMK core-microbiome showed an abundance of Fusobacterium, Tannerella and Mogibacterium, while the NSMK core revealed an abundance of Actinomyces, Capnocytophaga and Streptococcus, genera that are usually related to periodontal health. The microbiome inter-relationship was shown to be more inter-generic in SMK then in NSMK, indicating different microbiome cohesion. CONCLUSION: Smoking negatively affected the peri-implant microbiome, leading to a disease-associated state, even in clinically healthy individuals.

Simultaneous detection of Dialister pneumosintes and Filifactor alocis in endodontic infections by 16S rDNA-directed multiplex PCR.

Dialister pneumosintes and Filifactor alocis have been recently considered as candidate endodontic pathogens. In this study, we devised a 16S rDNA-directed multiplex PCR protocol for simultaneous detection of these two bacterial species in endodontic infections. Samples were taken from infected root canals associated with asymptomatic periradicular lesions as well as from cases of acute periradicular abscesses. DNA extracted from the samples was used as template for simultaneous detection of D. pneumosintes and F. alocis through a multiplex PCR assay. Two fragments of the expected sizes, one specific for D. pneumosintes and the other for F. alocis, were simultaneously amplified from a mixture of reference genomic DNA containing DNA from both species. Clinical samples that were positive for the target species showed a single band of the predicted size for each species. D. pneumosintes was detected by multiplex PCR in 11 samples (7 asymptomatic and 4 abscesses) and F. alocis was identified in 9 cases (6 asymptomatic and 3 abscesses). Six samples (3 asymptomatic and 3 abscesses) shared the two species. Data from the present study confirmed that D. pneumosintes and F. alocis are common members of the microbiota present in primary endodontic infections and thereby may participate in the pathogenesis of periradicular lesions. The proposed multiplex PCR assay is a simple, rapid, and accurate method for the simultaneous detection of these two candidate endodontic pathogens.

Detection of Filifactor alocis in endodontic infections associated with different forms of periradicular diseases.

Recent molecular studies have expanded the list of suspected endodontic pathogens. The aim of this study was to evaluate the occurrence of Filifactor alocis in primary endodontic infections associated with different forms of periradicular diseases. Identification by nested polymerase chain reaction was performed in root canal samples from teeth associated with either asymptomatic periradicular lesions or acute apical periodontitis. Samples were also taken by aspiration of purulent exudate associated with acute apical abscesses. DNA extracted from the samples was initially amplified using universal 16S rDNA primers followed by a second round of amplification using the first PCR products to detect a specific fragment of F. alocis 16S rDNA. F. alocis was detected in 12/21 (57.1%) root canal samples from teeth showing asymptomatic periradicular lesions and in 3/10 (30%) samples taken from root canals associated with acute apical periodontitis. This species occurred in 8/19 (42.1%) pus aspirates obtained from abscessed teeth. In general, F. alocis was detected in 23/50 (46%) samples taken from endodontic infections. These findings suggest that F. alocis is involved in the etiology of different forms of periradicular diseases and has the potential to be an endodontic pathogen.