Role of Dietary Fibre in Managing Periodontal Diseases-A Systematic Review and Meta-Analysis of Human Intervention Studies.

BACKGROUND: Periodontitis is a chronic multifactorial inflammatory disease, that leads to tooth loss and is associated with other systemic diseases. The role of dietary fibre in the prevention and management of periodontal diseases is not well understood. The objective of this systematic review and meta-analysis was to assess how an intake of dietary fibre affects periodontal diseases in humans and any concomitant effects on systemic inflammation. METHODOLOGY: Human interventional studies investigating the effects of oral fibre intake on various clinical parameters of periodontal diseases were included. Search strategy with MeSH and free-text search terms was performed on the following database: CINAHL Complete, EMBASE, MEDLINE, SciVerse Scopus®, and Web of Science Core Collection on 21 October 2021 and updated on 19 February 2023 to identify relevant studies. Articles were filtered using the Covidence© web-based platform software. Data were pooled using random effects meta-analysis. RESULTS: From all databases, a total of 19,971 studies were obtained. Upon title and abstract screening, 101 studies were included for full-text screening. Upon full-text screening, six studies were included for analysis. Of these, five were randomised controlled trials, and one was a sequential feeding trial involving fibre-rich daily diet for a 4-8 weeks period. Fibre-rich dietary intervention significantly reduced Clinical Attachment Loss/Level by 0.48 mm/tooth (95% CI, -0.63 to -0.33, p < 0.001), Bleeding On Probing by 27.57% sites/tooth (95% CI -50.40 to -4.74, p = 0.02), Periodontal Inflamed Surface Area by 173.88 mm2 (95% CI -288.06 to -59.69, p = 0.003), Plaque Index by 0.02 (95% CI -0.04 to -0.00, p = 0.04), and Gingival Index by 0.41 (95% -0.67 to -0.16, p= 0.002). A non-significant reduction was observed for Probing Depth (-0.17 mm/tooth; 95% CI, -0.37 to 0.02, p = 0.09). CONCLUSIONS: Fibre-rich dietary interventions are associated with a reduction of clinical and particularly inflammatory markers of periodontal diseases. This shows a promising effect of dietary fibre as an intervention for inflammatory conditions like periodontal diseases.

Role of prebiotic dietary fiber in periodontal disease: A systematic review of animal studies.

Background: Periodontitis is a chronic inflammatory condition affecting the supporting structures of a tooth in the oral cavity. The relationship between dietary fiber and periodontitis is poorly understood. The objective of this systematic review is to investigate if an intake of dietary fiber modulates periodontal disease in animal models and any concomitant effects on systemic inflammation, microbiota and their metabolites. Methods: Animal studies using periodontitis models with any form of fiber intervention were included. Studies with comorbidities that were mutually inclusive with periodontitis and animals with physiological conditions were excluded. Search strategy with MeSH and free-text search terms were finalized and performed on the 22nd of September 2021.CINAHL Complete, EMBASE, MEDLINE, SciVerse Scopus® and Web of Science Core Collection databases were used to identify studies. SYRCLE's risk of bias tool and CAMARADES were used for quality assessment. Results were synthesized utilizing Covidence© web-based platform software to remove duplicates, and the remaining studies were manually filtered. Results: A total of 7,141 articles were retrieved from all databases. Out of 24 full-text articles assessed for eligibility, four studies (n = 4) were included. Four studies involved the use of ß-(1,3/1,6)-glucan (n = 3) and mannan oligosaccharide (n = 1) at differing dosages for different study durations. All studies utilized a ligature-induced model of periodontitis in rats, either Wistar (n = 3) or Sprague-Dawley (n = 1). A dose-dependent relationship between the increased fiber intake and decrease in alveolar bone loss and pro-inflammatory markers was observed. Conclusion: The number of included studies is limited and narrow in scope. They highlight the importance of pre-clinical trials in this field with broader dietary fiber intervention groups before proceeding to clinical trials. The use of dietary fiber as an intervention shows promise in the reduction of inflammatory conditions like periodontitis. However, further research is required to delineate the relationship between diet and its effects on microbiota and their metabolites such as short chain fatty acids in animal models of periodontitis.

Peripheral T helper cell profiles during management of periodontitis.

AIM: Periodontitis has been associated with other systemic diseases with underlying inflammation responsible for the shared link. This study evaluated longitudinal variation in peripheral T helper cells in periodontitis patients undergoing management over 1 year. MATERIALS AND METHODS: Periodontal parameters and peripheral blood mononuclear cells (PBMCs) were collected from 54 periodontitis patients at baseline, and 3-, 6- and 12-months post-treatment and 40 healthy controls. IFN-γ+ , IL-4+ , IL-17+ and Foxp3+ and their double-positive expression were identified in CD4+ and TCRαß+ cells using flow cytometry. PBMCs were incubated with P. gingivalis, and IFN-γ, IL-4, IL-17 and IL-10 in cell supernatant were measured by ELISA. Cells and cytokines were also assessed based on clinical response to treatment where good (<10% of sites), moderate (10-20%) and poor (>20%) treatment outcome (TxO) groups had probing depths of ≥5 mm at study conclusion. RESULTS: IFN-γ+ cells were lower at baseline, and 3- and 6-months compared to health, whereas Foxp3+ cells were increased at 12-months compared to all preceding timepoints and health. The good TxO group showed treatment-related variation in IFN-γ+ and Foxp3+ cells, whereas the poor TxO group did not. IFN-γ and IL-17 cytokine expression in cell supernatants was significantly lower at baseline compared to health, and IFN-γ and IL-10 showed treatment-related decrease. CONCLUSION: This study suggests that IFN-γ+ and Foxp3+ cells may have a role in the systemic compartment in periodontitis. Periodontal management has local and systemic effects, and thus, assessment and management of periodontitis should form an integral part of overall systemic health.

A review of T helper 17 cell-related cytokines in serum and saliva in periodontitis.

Periodontitis is a chronic inflammatory disease with a complex underlying immunopathology. Cytokines, as molecular mediators of inflammation, play a role in all stages of disease progression. T helper 17 (Th17) cells are thought to play a role in periodontitis. Th17 cell development and maintenance requires a pro-inflammatory cytokine milieu, with many of the cytokines implicated in the pathogenesis of periodontitis. Serum and saliva are easily accessible biofluids which can represent the systemic and local environment to promote the development of Th17 cells. Here we review human clinical studies that investigate IL-1ß, IL-4, IL-6, IL-10, IL-17A, IL-17F, IL-21, IL-22, IL-23, IL-25, IL-31, IL-33, IFN-γ, sCD40L and TNF-α in serum and saliva in periodontitis. We highlight their putative role in the pathogenesis of periodontitis and place them within a wider context of animal and other clinical studies.

Peripheral memory T-cell profile is modified in patients undergoing periodontal management.

AIMS: T-cells are known to have a role in periodontitis, however, the effect of periodontal therapy on peripheral memory T-cells is unclear. This study evaluated variation in peripheral memory T-cells and red complex bacteria in sub-gingival plaque in patients undergoing periodontal management. METHODS: Peripheral blood mononuclear cells and sub-gingival plaque were collected from 54 periodontitis patients at baseline, 3-, 6- and 12-months post-therapy and 40 healthy controls. Periodontitis patients were divided into treatment outcome (TxO) groups based on prevalence of sites with probing depth ≥5 mm as good (<10% of sites), moderate (10-20%) or poor (>20%) at study conclusion. Naïve (TN -CCR7+ CD45RA+ ), central memory (TCM -CCR7+ CD45RA- ), effector memory (TEM -CCR7- CD45RA- ) and effector memory T-cells re-expressing CD45RA (TEMRA -CCR7- CD45RA+ ) were phenotyped using flow cytometry in CD4+ , CD8+ , CD4+ CD8+ and CD4- CD8- T-cells and red complex bacteria were quantified using qPCR. RESULTS: At baseline, periodontitis subjects had significantly greater mean probing depths and Porphyromonas gingivalis proportions, lower TN but higher CD4+ TCM , CD8+ TCM , CD4+ CD8+ TEM and CD4- CD8- TEM cell proportions compared to health. Periodontal therapy decreased mean probing depths, P. gingivalis proportions, TEM and CD4+ and CD8+ TCM cells, but increased TN and CD4+ and CD8+ TEMRA cells. The T-cell profile in the good TxO group showed therapy-related changes in CD4+ TEM , and CD8+ TN and TEM cells, whereas, no changes were observed in the poor TxO group. CONCLUSION: Management and the reduction in red complex bacteria were associated with changes in peripheral memory T-cells in periodontitis.

Peripheral neutrophil phenotypes during management of periodontitis.

BACKGROUND AND OBJECTIVES: Neutrophils are emerging as a key player in periodontal pathogenesis. The surface expression of cellular markers enables functional phenotyping of neutrophils which have distinct roles in disease states. This study aimed to evaluate the effect of periodontal management on neutrophil phenotypes in peripheral blood in periodontitis patients over one year. MATERIALS AND METHODS: Peripheral blood and the periodontal parameters, mean probing depth and percentage of sites with bleeding on probing (%BOP), were collected from 40 healthy controls and 54 periodontitis patients at baseline and 3-, 6- and 12- months post-treatment. Flow cytometry was used to identify CD11b+ , CD16b+ , CD62L- and CD66b+ expression on neutrophils, neutrophil maturation stages as promyelocytes (CD11b- CD16b- ), metamyelocytes (CD11b+ CD16b- ) and mature neutrophils (CD11b+ CD16b+ ), and suppressive neutrophil phenotype as bands (CD16dim CD62Lbright ), normal neutrophils (CD16bright CD62Lbright ) and suppressive neutrophils (CD16bright CD62Ldim ). RESULTS: CD62L- expression decreased with treatment. No differences were observed in neutrophil maturation stages in health or disease upon treatment. Suppressive and normal neutrophils showed a reciprocal relationship, where suppressive neutrophils decreased with treatment and normal neutrophils increased with treatment. In addition, %BOP was associated with suppressive neutrophils. CONCLUSION: This study demonstrates that management of periodontitis significantly modifies distinct neutrophil phenotypes in peripheral blood. Suppressive neutrophils may play a role in the pathogenesis of periodontitis. However, their exact role is unclear and requires further investigation.

T helper 17 cell-related cytokines in serum and saliva during management of periodontitis.

AIM: T helper (Th)17 cells are implicated in the pathogenesis of periodontitis. This study investigated the effect of periodontal management on fifteen Th17-related cytokines in serum and saliva in periodontitis patients. MATERIALS AND METHODS: Periodontal parameters, serum and saliva were collected from 40 healthy controls and 54 periodontitis subjects before treatment, and 3-, 6- and 12-months post-treatment. Cytokine concentrations of IL-1ß, IL-4, IL-6, IL-10, IL-17A, IL-17F, IL-21, IL-22, IL-23, IL-25, IL-31, IL-33, IFN-γ, sCD40L and TNF-α were determined by Luminex assay. RESULTS: IL-1ß, IL-6, sCD40L and TNF-α in serum, and IL-1ß, IL-6, IL-25 and IL-31 in saliva were significantly higher at baseline compared to health and decreased with treatment. In contrast, serum IL-31 was significantly lower at baseline compared to health and increased with treatment. In addition, salivary IL-10, IL-17A, IL-17F, IL-23, IL-33, IFN-γ and TNF-α also displayed treatment-related reduction. Correlation networks showed that cytokines in saliva displayed a higher number of correlations compared to serum in periodontitis. CONCLUSION: Treatment generally decreased cytokine concentrations except for serum IL-31 which showed a treatment-related increase. Serum cytokine concentrations may not be reflective of salivary cytokines. Saliva may be a better medium for cytokine detection compared to serum. Serum IL-31 and salivary IL-1ß, IL-6, IL-10 and TNF-α were significant predictors for mean probing depth and may be potential biomarkers of interest in the pathogenesis of periodontitis.