Page 12 - MDJ Volume 47 Number 2 ( Jul-Dec 2024)

Babu Osman, et al.: Oral microbiome in the elderly
range of genes from different bacterial species. Saliva is a detection of bogus species and exaggeration of microbial
[60]
good medium to study the oral microbiome as the salivary diversity. In addition, PCR is affected by limited primer
[66]
microbiota is partially shared with that of all different sites coverage, which can result in the failure to amplify some
of the oral cavity due to contact and saliva collection is taxa, particularly novel ones, and differential amplification
relatively non-invasive and easy to do. Saliva microbiota of templates, which can alter the relative abundance of
[61]
carries disease-associated functional signatures, potentially species and distort the original microbial community
distinguishing caries-active from caries-free individuals. structure. [66]
[47]
Studies have identified these differences in microbial
communities and metabolic functions. A gene catalogue conclusIon
was established for children with early childhood caries,
highlighting potential diagnostic markers and therapeutic The oral cavity contains a diverse microbiota and any
targets. [62] disruptions or imbalances in this microbial community,
especially in the presence of systemic diseases, may
The main application of NGS in microbiology is to replace induce the development of oral diseases such as dental
conventional pathogen characterisation by morphology, caries. The advancement of genomic technique provides
staining properties and metabolic criteria with genomic a greater understanding of how the oral microbiome is
definitions of pathogens. NGS, also known as high- associated with oral and systemic health. NGS using
[12]
throughput sequencing, can sequence hundreds of targeted 16s ribosomal RNA gene sequencing allows
genes simultaneously and offers deeper coverage of analysis of the oral microbiota with a relatively lower
microbial communities. This technique allows for cost and eliminating the need for culture or PCR
[63]
the unprecedented depth and breadth of microbial amplification to study the broad genomic group of
community analysis at a relatively lower cost, making it the oral microbiome in health and disease. There is a
an invaluable tool for studying the oral microbiome in need to further understand the relationship between
both health and disease. Characterising microbiota using oral microbiome and dental caries in the elderly with
NGS targets one or more regions of the 16S rRNA gene, diabetes and possibly use the salivary microbiome in the
which serves as a good marker for bacterial taxa due to its management of dental caries.
hypervariability. Multiple studies have used this approach
to explore the microbiomes of dental caries, providing Financial support and sponsorship
better insights into microorganism diversity, not limited to Nil.
bacteria. For example, one study characterised a healthy
oral microbiome and identified over 200 microbial genera,
generating a reference for eubiosis. This was enabled by Conflicts of interest
NGS techniques targeting the 16S rRNA gene, providing There are no conflicts of interest.
detailed information on the bacterial component’s
complexity. [64] references
In the past, conventional culture-dependent techniques 1. Usuga-Vacca M, Marin-Zuluaga DJ, Castellanos JE, Martignon S.
limited research into the oral microbiome because Association between root/coronal caries and individual factors in
many species are not cultivable. Culture-independent institutionalised elderly using ICDAS severity and activity. BMC
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Oral Health 2021;21:146.
molecular approaches, such as direct sequencing of 2. Gati D, Vieira AR. Elderly at greater risk for root caries: A look at
microbial DNA or sequencing amplified DNA using the multifactorial risks with emphasis on genetics susceptibility. Int
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barcoding genes (16S for bacteria and archaea and ITS 3. Machiulskiene V, Campus G, Carvalho JC, Dige I, Ekstrand KR,
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S. mutans, Lactobacillus, Propionibacterium, Veillonella 5. Hariyani N, Setyowati D, Spencer AJ, Luzzi L, Do LG. Root caries
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of NGS to explore microbiomes in diabetic elderly 2018;77:1-7.
individuals with dental caries is still lacking, presenting 6. Powers AC, Niswender KD, Rickels MR. Diabetes mellitus:
opportunities to investigate this vulnerable population. Management and therapies. In: Jameson JL, Fauci AS, Kasper DL,
Hauser SL, Longo DL, Loscalzo J, editors. Harrison’s Principles of
Despite the advanced technology of NGS, the PCR Internal Medicine. 20th ed. United States of America: McGraw-Hill
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relationship between dental caries, diabetes mellitus and oral
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38 Malaysian Dental Journal ¦ Volume 47 ¦ Issue 2 ¦ July-December 2024
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