[Oral ecosystem in elderly people]

The Oral Microbiome in the Elderly With Dental Caries and Health

With the aging of the population, dental caries in the elderly has received increasing attention. A comprehensive study of the oral microbiome is required to understand its polymicrobial etiology. The results of previous studies are limited and remain controversial. In this study, subjects 60 years and older with and without caries were recruited. Unstimulated saliva and dental plaque were collected from each subject and the bacterial 16S rDNA was amplified using PCR and sequenced by Illumina MiSeq high-throughput sequencing. A total of 92 samples were collected from 24 caries patients and 22 healthy controls. Sequences clustered into 147,531 OTUs, representing 16 phyla, 29 classes, 49 orders, 79 families, 149 genera, and 305 species. All predominant phyla, including Proteobacteria, Bacteroidetes, Firmicutes, Fusobacteria, Actinobacteria, and Saccharibacteria, were largely consistent in different groups, but different relative abundances could be observed. The core microbiome was defined with 246 shared species among groups, which occupied 80.7% of all the species detected. Alpha diversity showed no significant differences in bacterial richness or diversity between caries patients and healthy controls, but distinction existed between samples collected from dental plaque and saliva. Beta diversity analysis was performed by PCoA and hierarchical clustering analysis, showing similar results that microorganisms vary between the two niches. The biomarkers of different groups were defined by LEfSe analysis to identify potential caries-related and health-related bacteria. The co-occurrence analysis of the predominant genera revealed significant interactions among oral microbiota and exhibited more complex and aggregated bacterial correlations in caries-free groups. Finally, the functional prediction of the microbiota present in oral samples was performed by PICRUSt, indicating vigorous microbial metabolism in the oral bacterial community. Our study provides thorough knowledge of the microbiological etiology of elderly individuals with caries and is expected to provide novel methods for its prevention and treatment.

Molecular characterization of Candida dubliniensis and Candida albicans in the oral cavity of drug abusers using duplex polymerase chain reaction

Background and Purpose:

Candida dubliniensis is closely related to the most pathogenic and prevalent yeast, namely C. albicans.Candida species can opportunistically overgrow in vulnerable individuals and cause a variety of diseases. The current study aimed to identify and isolate C. dubliniensis species present in the Candida albicans species complex identified in the oral cavity of drug abusers.

Materials and Methods:

This study was conducted on 53 strains of C. albicans species complex, isolated from the oral mucosa of drug abusers in Isfahan, Iran. DNA extraction was accomplished through boiling procedure. Duplex polymerase chain reaction (PCR) was performed to amplify ITS1-5.8S-ITS2 region using four specific primers. Fungal species were identified based on the difference in the size of the bands created in the Agarose gel.

Results:

Out of the 53 isolates under study, 30 (56.6%) and 14 (26.4%) samples were identified as C. albicans and C. dubliniensis, respectively. In the remaining 9 samples (17%), both types of Candida species were confirmed.

Conclusion:

The findings of the present study revealed the presence of a noticeable amount of C. dubliniensis in the oral cavity of drug abusers. Therefore, the probable presence of this fungus should be considered during the examination of oral infection among this group. To date, no research has directly investigated this issue in Iran.

Relationship between removable prosthesis and some systemics disorders

This article reviews the dental literature concerning the potential impact of the removable prosthesis (RP) on the health status of patients with certain systemic diseases. Literature was surveyed using Medline/PubMed database resources, as well as a manual search, up to 2015 to identify appropriate articles that addressed the aim of this review. The research used keywords about associations between RP and six pathologies: Human immunodeficiency virus infection, diabetes mellitus, pulmonary diseases, gastric-Helicobacter pylori, cancer, and cardiovascular diseases. Analysis of literature showed that in patients with dentures having one or more of the six general conditions listed, Candida albicans organism is more frequently found in the oral flora compared to healthy denture wearer. Although causality has not been established and pending further research on this topic, the hygienic practices necessary to minimize the risk of numerous pathologies should be strengthened in the case of these patients, all the more in the presence of physical or psychological disability. The relationship between the general diseases and increasing of oral candidiasis denture patients is not explained. Therefore, attention to oral hygiene and professional care for removing C. albicans may be beneficial in these medically compromised patients.