Recent years have been marked by a paradigm shift in the study of the human microbiota, with a re-emergence of culture-dependent approaches. Numerous studies have been devoted to the human ...microbiota, while studies on the oral microbiota still remain limited. Indeed, various techniques described in the literature may enable an exhaustive study of the microbial composition of a complex ecosystem. In this article, we report different methodologies and culture media described in the literature that can be applied to study the oral microbiota by culture. We report on specific methodologies for targeted culture and specific culture techniques and selection methodologies for cultivating members of the three kingdoms of life commonly found in the human oral cavity, namely, eukaryota, bacteria and archaea. This bibliographic review aims to bring together the various techniques described in the literature, enabling a comprehensive study of the oral microbiota in order to demonstrate its involvement in oral health and diseases.
Among oral microbiota methanogens,
(
) has remained less studied than the well-characterised and cultivated methanogens
and
.
has been associated with different oral pathologies and was co-isolated ...with the
bacterium
(
) in one case of severe periodontitis. Here, reporting on two additional necrotic pulp cases yielded the opportunity to characterise two co-cultivated
isolates, both with
, as non-motile, 1-2-µm-long and 0.6-0.8-µm-wide Gram-positive coccobacilli which were autofluorescent at 420 nm. The two whole genome sequences featured a 31.3% GC content, gapless 1,834,388-base-pair chromosome exhibiting an 85.9% coding ratio, encoding a formate dehydrogenase promoting
growth without hydrogen in GG medium. These data pave the way to understanding a symbiotic, transkingdom association with
and its role in oral pathologies.
was the sole
representative to be cultured and detected by molecular methods in the human gut microbiota, further associated with digestive and respiratory diseases, leaving unknown the actual ...diversity of human-associated
species. Here, a novel
species,
Methanosphaera massiliense (
. M. massiliense) sp. nov. was isolated by culture using a hydrogen- and carbon dioxide-free medium from one human feces sample.
. M. massiliense is a non-motile, 850 nm Gram-positive coccus autofluorescent at 420 nm. Whole-genome sequencing yielded a 29.7% GC content, gapless 1,785,773 bp genome sequence with an 84.5% coding ratio, encoding for alcohol and aldehyde dehydrogenases promoting the growth of
. M. massiliense without hydrogen. Screening additional mammal and human feces using a specific genome sequence-derived DNA-polymerase RT-PCR system yielded a prevalence of 22% in pigs, 12% in red kangaroos, and no detection in 149 other human samples. This study, extending the diversity of
in human microbiota, questions the zoonotic sources of
. M. massiliense and possible transfer between hosts.IMPORTANCEMethanogens are constant inhabitants in the human gut microbiota in which
was the only cultivated
representative. We grew
Methanosphaera massiliense sp. nov. from one human feces sample in a novel culture medium under a nitrogen atmosphere. Systematic research for methanogens in human and animal fecal samples detected
. M. massiliense in pig and red kangaroo feces, raising the possibility of its zoonotic acquisition. Host specificity, source of acquisition, and adaptation of methanogens should be further investigated.
Methanobrevibacter smithii (M. smithii), the most prevalent and abundant gut methanogen, detoxifies hydrogen into methane and is, therefore, of paramount importance for the equilibrium of the gut ...microbiota. The isolation by culture of M. smithii has routinely relied upon hydrogen‑carbon dioxide-enriched, oxygen-deprived atmospheres. In this study, we developed a medium referred to as “GG”, which allowed for M. smithii growth and isolation by culture in an oxygen-deprived atmosphere, with no supply of either hydrogen or carbon dioxide, making it easier to detect M. smithii by culture in clinical microbiology laboratories.
•Methanobrevibacter smithii can grow without hydrogen using formate and probably acetate.•GG medium eases Methanobrevibacter smithii routine culture, avoiding the explosive hydrogen.•Methanobrevibacter smithii can be associated with bacteria that do not produce hydrogen such as Staphylococcus and Streptococcus genus.
Teaching caries lesion management with operative care requires tooth models with highly realistic anatomical detail and caries lesions that can be assessed using ICDAS. This study aimed to develop ...and evaluate a new 3D-printed teeth model for ICDAS assessment and caries removal for pre-clinical hands-on education.
Printable tooth with different layers for enamel, dentin and carious lesions was designed and tested by 31 dental students. They were asked to visually and radiologically assess the ICDAS severity of the simulated carious lesions, establish the therapeutic strategy according to CariesCare 4D, and perform a qualitative assessment of the models based on five-point Likert scale items.
Concerning carious lesions, the texture was realistic, and the shade was adequate for 94% and 97% of the participants. Ninety per cent of the participants found the model adequate to perform an ICDAS visual assessment. Seventy-four per cent of the students found the hardness adequate. Concerning the difference in shade and the noticeable hardness difference between enamel and dentin, participants have mixed agreement with a proportion of 61% and 55%, respectively. All the participants agreed these 3D-printed models provide a good caries simulation, are suitable for hands-on operative dentistry courses, and that learning outcomes better than the standard model.
The present work shows that rapid prototyping paves the way for customized educational models capable of supporting operative but also preoperative skills. 3D printing opens up new opportunities by reducing the gap between pre-clinical training and clinical reality in caries management, which can positively impact the quality of patient care.
Understanding that dental carious lesions occur as a result of the action of micro-organisms in the dental plaque biofilm, where demineralisation on the tooth surface is the first sign of the ...disease, such incipient lesions can be treated using preventive, non-operative and minimally invasive operative dentistry. If the caries process is left unmanaged, the lesions progress towards cavitation, leading to more invasive treatments. This article discusses the principles of preventive, non-invasive and micro-invasive treatments of early carious lesions, outlining the clinical situations where these therapies can be applied.
Among oral microbiota methanogens, Methanobrevibacter massiliense (M. massiliense) has remained less studied than the well-characterised and cultivated methanogens Methanobrevibacter oralis and ...Methanobrevibacter smithii. M. massiliense has been associated with different oral pathologies and was co-isolated with the Synergistetes bacterium Pyramidobacter piscolens (P. piscolens) in one case of severe periodontitis. Here, reporting on two additional necrotic pulp cases yielded the opportunity to characterise two co-cultivated M. massiliense isolates, both with P. piscolens, as non-motile, 1–2-µm-long and 0.6–0.8-µm-wide Gram-positive coccobacilli which were autofluorescent at 420 nm. The two whole genome sequences featured a 31.3% GC content, gapless 1,834,388-base-pair chromosome exhibiting an 85.9% coding ratio, encoding a formate dehydrogenase promoting M. massiliense growth without hydrogen in GG medium. These data pave the way to understanding a symbiotic, transkingdom association with P. piscolens and its role in oral pathologies.
