Distinguishing the Signals of Gingivitis and Periodontitis in Supragingival Plaque: a Cross-Sectional Cohort Study in Malawi

Abstract

Periodontal disease ranges from gingival inflammation (gingivitis) to the inflammation and loss of tooth-supporting tissues (periodontitis). Previous research has focused mainly on subgingival plaque, but supragingival plaque composition is also known to be associated with disease. Quantitative modeling of bacterial abundances across the natural range of periodontal severities can distinguish which features of disease are associated with particular changes in composition. We assessed a crosssectional cohort of 962 Malawian women for periodontal disease and used 16S rRNA gene amplicon sequencing (V5 to V7 region) to characterize the bacterial compositions of supragingival plaque samples. Associations between bacterial relative abundances and gingivitis/periodontitis were investigated by using negative binomial models, adjusting for epidemiological factors. We also examined bacterial cooccurrence networks to assess community structure. The main differences in supragingival plaque compositions were associated more with gingivitis than periodontitis, including higher bacterial diversity and a greater abundance of particular species. However, even after controlling for gingivitis, the presence of subgingival periodontitis was associated with an altered supragingival plaque. A small number of species were associated with periodontitis but not gingivitis, including members of Prevotella, Treponema, and Selenomonas, supporting a more complex disease model than a linear progression following gingivitis. Cooccurrence networks of periodontitis-associated taxa clustered according to periodontitis across all gingivitis severities. Species including Filifactor alocis and Fusobacterium nucleatum were central to this network, which supports their role in the coaggregation of periodontal biofilms during disease progression. Our findings confirm that periodontitis cannot be considered simply an advanced stage of gingivitis even when only considering supragingival plaque. IMPORTANCEPeriodontal disease is a major public health problem associated with oral bacteria. While earlier studies focused on a small number of periodontal pathogens, it is now accepted that the whole bacterial community may be important. However, previous highthroughput marker gene sequencing studies of supragingival plaque have largely focused on high-income populations with good oral hygiene without including a range of periodontal disease severities. Our study includes a large number of low-income participants with poor oral hygiene and a wide range of severities, and we were therefore able to quantitatively model bacterial abundances as functions of both gingivitis and periodontitis. A signal associated with periodontitis remains after controlling for gingivitis severity, which supports the concept that, even when only considering supragingival plaque, periodontitis is not simply an advanced stage of gingivitis. This suggests the future possibility of diagnosing periodontitis based on bacterial occurrences in supragingival plaque.

Plaque‐induced gingivitis: Case definition and diagnostic considerations

“…The introduction in the late 90s of open‐ended molecular methods and their application to the detection of microbes broadened significantly the spectrum of bacterial species associated with periodontal diseases, with many previously unidentified and/or uncultivated bacteria linked with periodontitis . In the last few years, these molecular techniques have been applied, along with novel statistical approaches, to the study of the biofilm associated with gingivitis and compared to health and periodontitis . These studies have demonstrated that the transition from health to disease follows the principles of primary ecological succession, with change in abundances of indigenous species, rather than acquisition of newer organisms.…”

“…[168][169][170][171] In the last few years, these molecular techniques have been applied, along with novel statistical approaches, to the study of the biofilm associated with gingivitis and compared to health and periodontitis. [172][173][174][175][176][177] These studies have demonstrated that the transition from health to disease follows the principles of primary ecological succession, with change in abundances of indigenous species, rather than acquisition of newer organisms. Even as these studies identified previously unrecognized species in gingivitis, they confirmed that the biofilms associated with gingivitis and periodontitis share most species (albeit with quantitative differences).…”

Dental plaque–induced gingival conditions

“…Histopathologic changes include the elongation of rete ridges into the gingival connective tissue, vasculitis of blood vessels adjacent to the junctional epithelium, progressive destruction of the collagen fiber network with changes in collagen types, cytopathologic alterations of resident fibroblasts, and a progressive inflammatory/ immune cellular infiltrate. 16 Although recent studies suggest that bacterial phylotypes associated with gingivitis are distinct from those associated with health or periodontitis, [21][22][23][24] further studies are needed to clearly define the microbial community of gingivitis. In this regard, gingivitis is a non-specific dental plaque-induced inflammatory condition, a concept that remains unchanged from…”

Periodontal Disease Distribution, Risk Factors, and Importance of Primary Healthcare in the Clinical Parameters Improvement

“…The importance in the implementation of a health education program and of a periodontal conservative treatment for this population group is our main finding. It has been considered that periodontal disease is the most important public health issue, in particular in low income locations due to its high prevalence; and since an increase has been observed with the risk of having (Shaw et al, 2016).…”