Associations Between Serum 25-Hydroxyvitamin D and Periodontal Pocketing and Gingival Bleeding: Results of a Study in a Non-Smoking Population in Finland

Associations of Serum Vitamin D With Dental Caries and Periodontitis: The HUNT Study

OBJECTIVE

To study the relationships of serum 25-hydroxyvitamin D [25(OH)D] with dental caries and periodontitis in a general Norwegian adult population.

METHODS

We analysed a subsample of 1605 participants from the Trøndelag Health Study (HUNT) in Norway that had serum 25(OH)D levels measured in HUNT3 (2006-08) and oral health assessed in the HUNT4 Oral Health Study (2017-19). Negative binomial and Poisson regression models were used to estimate the ratios of means (RMs; for count oral outcomes) and prevalence ratios (PRs; for dichotomous oral outcomes).

RESULTS

Serum 25(OH)D was inversely associated with the number of decayed teeth in a dose-response gradient (<30.0 nmol/L: RM 1.41, 95% CI 1.07-1.85; 30.0-49.9 nmol/L: 1.14, 0.98-1.32 and ≥75.0 nmol/L: 0.84, 0.67-1.04, as compared to the 50.0-74.9 nmol/L group, P for trend <.001). Each 25 nmol/L decrease in 25(OH)D level was associated with a 15% (RM 1.15, 95% CI 1.05-1.26) increase in the mean number of decayed teeth. Serum 25(OH)D <30.0 nmol/L was associated with a 35% higher prevalence of severe periodontitis (PR 1.35, 95% CI 1.00-1.83). No association was observed between 25(OH)D and the number of natural teeth.

CONCLUSION

The present study suggested that serum 25(OH)D level had an inverse and dose-response association with the number of decayed teeth, and serum 25(OH)D <30 nmol/L was associated with a higher prevalence of severe periodontitis in this Norwegian adult population.

Vitamin intake and periodontal disease: a meta-analysis of observational studies

OBJECTIVE

A meta-analysis was performed to assess the epidemiological correlation between dietary intake of various types of vitamin intake and the risk of periodontal disease.

METHODS

A comprehensive computerized search was conducted in eight databases, namely PubMed, Web of Science, Embase, Cochrane Library, China Biology Medicine Disc, CNKI, VIP, and WanFang Database, and a random effect model was applied to combine pooled odds ratio (ORs) with corresponding 95% confidence intervals (CIs) of the included studies, and the sensitivity analysis was performed to explore the impact of a single study on the comprehensive results.

RESULTS

We finally included 45 effect groups from 23 observational studies, with a total number of study participants of 74,488. The results showed that higher levels of vitamin A (OR: 0.788, 95% CI: 0.640-0.971), vitamin B complex (OR: 0.884, 95% CI: 0.824-0.948), vitamin C (OR: 0.875, 95% CI: 0.775-0.988), vitamin D (OR: 0.964, 95% CI: 0.948-0.981), and vitamin E (OR: 0.868, 95% CI: 0.776-0.971) intake all were negatively correlated with periodontal disease. After removing each study, leave-one-out sensitivity analysis indicated no significant change in the overall results of any of the five meta-analyses.

CONCLUSIONS

The results from this meta-analysis demonstrated a negative association between high-dose vitamin A, vitamin B complex, vitamin C, vitamin D, and vitamin E consumption and the likelihood of developing periodontal disease, revealing the significant role of vitamins in preventing periodontal disease.

Association of Serum Vitamin D With Periodontal Disease

OBJECTIVE

There are conflicting reports on the relationship between vitamin D and periodontal disease. Our research is intended to further analyse the association between serum 25(OH)D3, a vitamin D precursor and periodontal disease based on a large national survey sample in Japan.

METHODS

We downloaded the 2009-2018 National Health and Nutrition Examination Survey (NHANES) cycle, which included a total of 23,324 samples. Logistic regression of factors influencing perioral disease including periodntal disease, and subgroup logistic regression were performed to analyse the relationship between serum vitamin D and perioral disease, using WTMEC2YR as weights for regression analysis. Then machine learning model-based prediction of perioral disease onset was performed, and the machine learning algorithms used included boost tree, artificial neural network, AdaBoost, and random forest.

RESULTS

We evaluated the vitamin D, age, sex, race, education, marriage, body mass index, ratio of family income to poverty (PIR), smoking, alcohol consumption, diabetes, and hypertension as variables in the included samples. Vitamin D was negatively associated with perioral disease; compared with Q1, the odds ratios and 95% CI were 0.8 (0.67-0.96) for Q2, 0.84 (0.71-1.00) for Q3, and 0.74 (0.6-0.92) for Q4 (P for trend <.05), respectively. The results of the subgroup analysis showed that the effect of 25(OH)D3 on periodontal disease was more pronounced in women younger than 60 years. Based on the accuracy and receiver operating characteristic curve, we concluded that a boost tree was a relatively good model to predict periodontal disease.

CONCLUSIONS

Vitamin D might be a protective factor for periodontal disease, and boost tree analysis we emplyed was a relatively good model to predict perioral disease.

The role of vitamin D in periodontal health and disease

Vitamin D plays an essential role in calcium and bone metabolism, immune regulation and possesses profound anti-inflammatory effects. Evidence suggests that low serum vitamin D is associated with increased severity of periodontitis, a chronic inflammatory condition characterised by destruction of the supporting tissues surrounding the tooth, which has several shared risk factors with other chronic non-communicable diseases. The biological functions of vitamin D are mediated by its strong anti-microbial, anti-inflammatory, and host modulatory properties. Experimental periodontitis models involving targeted deletion of 1α-hydroxylase, the enzyme responsible for the conversion of inactive substrate to active 1,25(OH)₂ D₃ (calcitriol), showed augmented alveolar bone loss and gingival inflammation. Vitamin D receptor (VDR) gene polymorphisms have also been associated with increased severity of periodontitis. Thus, the involvement of vitamin D in the pathogenesis of periodontitis is biological plausible. Clinical studies have consistently demonstrated an inverse relationship between serum 25OHD₃ and periodontal disease inflammation. However, due to the paucity of well-designed longitudinal studies, there is less support for the impact of vitamin D status on periodontal disease progression and tooth loss. The evidence emphasises the importance of maintaining vitamin D sufficiency in supporting periodontal health. This review aims to first examine the biological mechanisms by which vitamin D might influence the pathogenesis of periodontal disease and second, discuss the clinical evidence which implicate the role of vitamin D in periodontal disease.

Vitamin D levels and oral health in stroke patients during inpatient rehabilitation

BACKGROUND

Stroke is a severe that restricts the individual's functions, effects the oral health.

OBJECTIVES

The aim of this study was to investigate the relationship between oral health and vitamin D levels in stroke patients in rehabilitation units.

METHODS

Participants with stroke, and age- and sex-matched healthy controls were recruited for the study. Oral Health Impact Scale-14 (OHIP-14), Decayed, Missing, Filled Teeth (DMFT) Index, Community Periodontal Index of Treatment Needs (CPITN), Gingival Index (GI) and Plaque Index (PI) were assessed for all participants. Barthel Index (BI), Brunnstrom Recovery Scale (BRS) and Modified Ashworth Scale (MAS) assessed for the stroke patients. Vitamin D levels of each participant were recorded.

RESULTS

The stroke patients' DMFT index and OHIP-14 values were higher than those of the healthy controls (p < .05). However, no significant differences were observed in terms of CPTIN, PI, or GI scores (p > .05). No statistically significant difference was determined in the DMFT index, OHIP-14 scores, Community Periodontal Index of Treatment Needs (CPITN), PI (Plaque Index) and GI (Gingival Index) scores according to vitamin D levels among the stroke patients (p > .05). Stroke patients' functional scores (BRS, MAS and BI), vitamin D levels and oral health status (OHIP-14, DMFT, CPITN, PI and GI) were subjected to correlation analysis. This revealed significant negative correlation between BRS (arm, hand and leg), and BI and OHIP-14 scores (p < .05).

CONCLUSION

Although the DMFT index and oral health-related quality of life were adversely affected in stroke patients, no relationship was found between vitamin D and oral health status.

Dietary vitamin D and calcium and periodontitis: A population-based study

Aim

This study aimed to explore the relationship between dietary vitamin D and calcium intake and periodontitis among adults and whether it differs from males to females.

Methods

Cross-sectional analysis of a population-based cohort study with adults aged 20 to 60 from Southern Brazil. Intake of vitamin D and calcium were gathered in 2012 using two 24h-dietary recalls. Clinical examination assessed the clinical attachment level and bleeding on probing. Confounders included sex, age, family income, smoking, and obesity. The controlled direct effect of vitamin D and calcium on periodontitis was examined using marginal structural modeling. Analyses were also stratified by sex.

Results

Of the 1,066 investigated adults (mean age 35 ± 11.7 years; 49% females), 12.3% (95%CI 10.2;14.7) had periodontitis. Calcium intake had a direct protective effect on periodontitis (risk ratio (RR) 0.61; 95%CI 0.45;0.83), whereas no association between vitamin D and periodontitis was observed (RR 1.13; 95%CI 0.82;1.56). Stratified analyses revealed a null association between both vitamin D and calcium intake and periodontitis among men, but a protective association between calcium and intake and periodontitis among women (RR 0.56; 95%CI 0.38;0.79), while vitamin D remained without any association (RR 1.07; 95%CI 0.72;1.61).

Conclusion

Our findings suggest a protective association between dietary calcium intake and periodontitis among women.

ORAL HEALTH AND VITAMIN D IN ADULT - A SYSTEMATIC REVIEW

This systematic review aimed to provide a synthesis of the evidence relating to how the provision of Vitamin D supplements influences oral health status. An electronic database search was performed across six databases using a standardised search strategy. The PICO framework was used to define the review question. The screening and selection followed PRISMA process. The quality of reporting was assessed using CONSORT guidelines, and the bias was assessed using the revised Cochrane tool RoB2. A total of 1812 studies were retrieved. 1427 studies were excluded due to unmet inclusion criteria. Full texts of 75 potential studies were retrieved and ultimately six studies met the inclusion criteria. There were limitations in the quality of reporting of studies (between 49% and 73%). 70% of the risk of bias items were in the low risks category. Vitamin D interventions varied with respect to dosage and duration. Qualitative syntheses identified significantly better oral health outcomes. Heterogeneity of study design, intervention and outcomes precluded quantitative synthesis. Few clinical trials investigated the effect of Vitamin D supplementation on oral health. There is considerable heterogeneity among studies interventions and oral health outcomes. Quality of reporting of studies have limitations and there is evidence of study biases. Nonetheless, qualitative synthesis of the evidence suggest that Vitamin D supplements improve oral health outcomes, particularly periodontal health. Calcium may also play a significant role. Further high-quality trials are required of comparable Vitamin D supplements with similar oral health outcomes focus to inform quantitative synthesis of the evidence.

A Mendelian randomization study on the effect of 25-hydroxyvitamin D levels on periodontitis

BACKGROUND

25-hydroxy vitamin D (25OHD) levels have been proposed to protect against periodontitis based on in vitro and observational studies but evidence from long-term randomized controlled trials (RCTs) is lacking. This study tested whether genetically proxied 25OHD is associated with periodontitis using Mendelian randomization (MR).

METHOD

Genetic variants strongly associated with 25OHD in a genome-wide association study (GWAS) of 417,580 participants of European ancestry were used as instrumental variables, and linked to GWAS summary data of 17,353 periodontitis cases and 28,210 controls. In addition to the main analysis using an inverse variance weighted (IVW) model, we applied additional robust methods to control for pleiotropy. We also undertook sensitivity analyses excluding single nucleotide polymorphisms (SNPs) used as instruments with potential pleiotropic effects and used a second 25OHD GWAS for replication. We identified 288 SNPs to be genome-wide significant for 25OHD, explaining 7.0% of the variance of 25OHD levels and providing ≥90% power to detect an odds ratio (OR) of ≤ 0.97.

RESULTS

MR analysis suggested that a 1 standard deviation increase in natural log-transformed 25OHD was not associated with periodontitis risk (IVW OR = 1.04; 95% confidence interval (CI): 0.97-1.12; P-value = 0.297). The robust models, replication, and sensitivity analyses were coherent with the primary analysis.

CONCLUSIONS

Collectively, our findings suggest that 25OHD levels are unlikely to have a substantial effect on the risk of periodontitis, but large long-term RCTs are needed to derive definitive evidence on the causal role of 25OHD in periodontitis. This article is protected by copyright. All rights reserved.

The association between vitamin D level and periodontal disease in Saudi population, a preliminary study

OBJECTIVE

Among other regulatory functions, vitamin D has a role in modulating the inflammatory process of periodontal disease. Therefore, this retrospective study aimed to assess the relationship between vitamin D levels and periodontal health in dental patients from the Eastern Province of Saudi Arabia.

METHODS

Radiographs and serum vitamin D levels of patients seeking dental treatment were collected. Exclusion criteria were systemic disease, smoking, recent vitamin D supplementation, and previous periodontal surgery. Gender, age, and alveolar crest height (ACH) were recorded. A total of 67 patients were categorized into three groups according to their serum vitamin D level (<10, <20, and > 20 ng/mL) and their bone loss compared.

RESULTS

Differences in means were compared by t-test. ANOVA was used to compare vitamin D groups and the corresponding ACH, as well as the correlation (p < .05). Patients with vitamin D levels > 20 ng/mL demonstrated a mean ACH of 1.6 mm. The mean ACH was 3.1 mm for those with vitamin D levels < 20 ng/mL, and 4.6 mm for vitamin D levels < 10 ng/mL. A weak negative correlation was found between vitamin D and ACH in all groups (r = -0.055, p = .7).

CONCLUSION

Serum vitamin D level seems to be an important factor that influences oral health, especially the periodontal condition, of both male and female patients.

Relationship between Vitamin D Deficiency and Periodontitis in Korean Adults Aged ≥60 Years: Analysis of Data from the Korea National Health and Nutrition Examination Survey (2013-2014)

There have been contradictory reports on the effects of vitamin D in the prevention of periodontitis. We analyzed the association between vitamin D status (levels of plasma 25(OH)D) and periodontitis using the Korea National Health and Nutrition Examination Survey (KNHANES) 2013–2014 database. Among the participants in the KNHANES (2013–2014), only those aged ≥60 years who completed a health interview survey, periodontal examination, and blood test were included in the study. Thus, data from 701 participants were used in the final analysis. Periodontal status was evaluated using the Community Periodontal Index (CPI), and periodontitis was defined as having a CPI score of 3 or 4. Plasma 25(OH)D levels were classified according to two criteria: 20 ng/mL and quartile value. The chi-square test and multivariate logistic regression analyses were performed to analyze the prevalence of periodontitis according to plasma 25(OH)D levels. Univariate analyses showed that periodontitis was not significantly associated with plasma 25(OH)D levels. In the multivariate logistic regression model adjusted for sociodemographic characteristics, the difference in the prevalence of periodontitis between those with a normal range of 25(OH)D and those with low plasma of 25(OH)D levels was not statistically significant. Vitamin D intake has been reported to have benefits in maintaining periodontal health; however, total plasma 25(OH)D levels showed no significant association with periodontitis based on CPI scores in this study. Additionally, these findings reaffirmed the importance of toothbrushing and smoking cessation to prevent periodontitis in people aged ≥60 years.

Association of Systemic Sclerosis and Periodontitis with Vitamin D Levels

The aim of the present study was to analyze the association among systemic sclerosis (SSc), periodontitis (PT); we also evaluated the impact of PT and SSc on vitamin D levels. Moreover, we tested the association with potential confounders. A total of 38 patients with SSc, 40 subjects with PT, 41 subjects with both PT and SSc, and 41 healthy controls were included in the study. The median vitamin D levels in PT subject were 19.1 (17.6-26.8) ng/mL, while SSc + PT group had vitamin d levels of 15.9 (14.7-16.9) ng/mL, significantly lower with respect to SSc patients (21.1 (15.4-22.9) ng/mL) and to healthy subjects (30.5 (28.8-32.3) ng/mL) (p < 0.001). In all subjects, vitamin D was negatively associated with c-reactive protein (CRP) (p < 0.001) and with probing depth (PD), clinical attachment level (CAL), bleeding on probing (BOP), and plaque score (PI) (p < 0.001 for all parameters) and positively related to the number of teeth (p < 0.001). Moreover, univariate regression analysis demonstrated an association among high low-density lipoproteins (LDL) cholesterol (p = 0.021), CRP (p = 0.014), and PT (p < 0.001) and reduced levels of vitamin D. The multivariate regression analysis showed that PT (p = 0.011) and CRP (p = 0.031) were both predictors of vitamin D levels. Subjects with PT and SSc plus PT had significant lower vitamin D values with respect to SSc and to healthy subjects. In addition, PT seems negatively associated with levels of vitamin D in all analyzed patients.

Expression of vitamin D 1α-hydroxylase in human gingival fibroblasts in vivo

Background

Vitamin D 1α-hydroxylase CYP27B1 is the key factor in the vitamin D pathway. Previously, we analyzed the expression of CYP27B1 in human gingival fibroblasts in vitro. In the present study, we analyzed the gingival expression of CYP27B1 in vivo.

Methods

Forty-two patients with periodontitis Stage IV Grade C and 33 controls were recruited. All patients with periodontitis had unsalvageable teeth and part of the wall of the periodontal pocket was resected and obtained after tooth extraction. All controls needed crown-lengthening surgery, and samples of gingiva resected during surgery were also harvested. All the individuals' gingivae were used for immunohistochemistry and immunofluorescence. In addition, gingivae from seventeen subjects of the diseased group and twelve subjects of the control group were analyzed by real-time PCR.

Results

Expression of CYP27B1 was detected both in gingival epithelia and in gingival connective tissues, and the expression in connective tissues colocalized with vimentin, indicating that CYP27B1 protein is expressed in gingival fibroblasts. The expression of CYP27B1 mRNA in gingival connective tissues and the CYP27B1 staining scores in gingival fibroblasts in the diseased group were significantly higher than those in the control group.

Conclusions

Expression of CYP27B1 in human gingival tissues was detected, not only in the fibroblasts of gingival connective tissues, but also in the gingival epithelial cells, and might be positively correlated with periodontal inflammation.

Periodontal health and disease: The contribution of genetics

Periodontitis is an infectious, inflammatory disease that is associated with a complex interplay between specific bacteria, host response, and environmental factors. Because of its high degree of familial aggregation, specifically for the more aggressive forms of the disease, genetics factors have been implicated in disease pathogenesis for several decades. This review provides an overview of what we currently know regarding the genetic and epigenetic contributions to periodontal disease and discusses future opportunities in the field.

Extending the vitamin D pathway to vitamin D3 and CYP27A1 in periodontal ligament cells

BACKGROUND

In periodontal connective tissue cells, the vitamin D pathway has been elucidated, and vitamin D₃ in the main storage form, 25-hydroxy vitamin D₃ (25[OH]D₃ ), and the functional form, 1,25-dihydroxy vitamin D₃ (1,25[OH]₂ D₃ ), have been found to induce the expression of human cationic antimicrobial protein (hCAP-18)/LL-37. Moreover, synergistic effects between Toll-like receptor agonists and 25(OH)D₃ have been reported. This research aimed at extending the vitamin D pathway to vitamin D₃ and CYP27A1 in human periodontal ligament cells (hPDLCs) to further explore its function in periodontal inflammatory reaction.

METHODS

Vitamin D₃ was used to stimulate hPDLCs in the presence or absence of Porphyromonas gingivalis lipopolysaccharide (Pg-LPS). Conversely, CYP27A1 RNA interference was performed to further validate the findings. The mRNA expression of hCAP-18 was determined with real-time polymerase chain reaction. Monocyte chemotactic protein-1 (MCP-1) and interleukin-8 (IL-8) were also detected. The cell supernatant levels of LL-37 were detected with enzyme-linked immunosorbent assay.

RESULTS

Vitamin D₃ significantly enhanced the generation of hCAP-18/LL-37. A combination of Pg-LPS and vitamin D₃ significantly promoted hCAP-18/LL-37 expression. When the expression of CYP27A1 was knocked down with RNA interference, the induction of hCAP-18/LL-37 expression was significantly inhibited. Therefore, the mRNA levels of MCP-1 and IL-8 in hPDLCs were significantly decreased through the vitamin D pathway.

CONCLUSION

The vitamin D pathway from vitamin D₃ to hCAP-18/LL-37 exists in hPDLCs, and CYP27A1 might be involved in periodontal immune defense.

Association of vitamin D in patients with periodontitis: A cross-sectional study

BACKGROUND AND OBJECTIVE

Vitamin D has been considered to possess anti-inflammatory and antimicrobial activity, which may be a link for the known interaction of periodontitis (CP) and coronary heart disease (CHD). This study investigated the association between serum vitamin D levels and periodontitis in patients with CP and with CHD. Furthermore, the objective was to determine whether periodontitis and CHD had an impact on serum vitamin D levels.

MATERIAL AND METHODS

Using a cross-sectional design, a total of 46 patients with CP, 45 patients with CHD, 45 patients with both CP and CHD, and 43 healthy patients were enrolled in the present study.

RESULTS

Patients in the CP (17.4 ± 5.2 ng/mL) and in the CP + CHD (16.5 ± 5.6 ng/mL) group presented a significantly lower mean serum level of 25(OH)vitamin D compared to patients in the CHD (24.6 ± 3.7 ng/mL) and healthy control groups (29.9 ± 5.4 ng/mL) (P < .001). 25(OH)vitamin D levels were positively correlated with the number of teeth and negatively with C-reactive protein (CRP) and all periodontal parameters (P < .001). In all patients, there was a proportional increase of 25(OH)vitamin D levels with a progressive increase in number of teeth (P-trend <.001) while there were a proportional decrease in 25(OH)vitamin D levels with a progressive increase in clinical attachment level (CAL, P-trend = .001), probing depth (PD, P-trend = .006), and bleeding sites (BOP, P-trend <.001) levels.

CONCLUSION

Patients with CP and CP + CHD presented significantly lower serum levels of vitamin D compared to CHD and healthy controls. Moreover, the presence of CP negatively influenced serum vitamin D levels.

Could Vitamin D influence risk for Periodontal Disease - to "D" or not to "D"?

PURPOSE OF REVIEW

The purpose of this review is to discuss the literature on associations between vitamin D and periodontal disease, including its strengths and weaknesses. Future direction for continued work in this area is provided.

RECENT FINDINGS

Research in cross-sectional cohorts, surveys, and case-control studies provide support for a role of vitamin D in periodontal disease, especially using clinical indicators such as bleeding on probing and clinical attachment loss. However, these studies have a number of limitations. They cannot establish temporality of these associations. Most case-control studies have been limited in sample size and have inconsistent findings. A number of cross-sectional studies are restricted to select populations (e.g., persons with HIV, diabetes, rheumatoid arthritis) limiting extrapolation of findings to the general aging population.Fewer prospective studies have been conducted, and only three have examined associations using a biomarker for vitamin D that reflects exposure from all its sources (sunlight, diet and supplements). One study is limited by using self-reported measures of disease outcomes, and only two used measures of alveolar crestal height. However, of the prospective studies published, there is a suggestion that vitamin D might prevent against tooth loss. Only two randomized controlled trials have examined these associations, and they support the effects of vitamin D supplementation on prevention of tooth loss and gingival bleeding.

SUMMARY

We strongly suggest that new research should focus on prospective study designs with followup of participants longer than a decade and long-term clinical trials. Such studies should incorporate measures of alveolar bone loss and tooth loss with indication for reason for tooth loss. Such clinical trials should be designed to examine both the influence of vitamin D supplementation alone as well as with other nutrients (e.g., calcium) or therapeutic medications (e.g., bisphosphonates). Currently, there is no strong evidence to suggest that vitamin D protects against development of periodontal disease.

1,25-dihydroxyvitamin D3 suppresses lipopolysaccharide-induced interleukin-6 production through aryl hydrocarbon receptor/nuclear factor-κB signaling in oral epithelial cells

Background

Antiinflammatory effect of 1,25-dihydroxyvitamin D₃ (1,25D3) has been reported in periodontitis, but the exact mechanisms remain unclear. Oral epithelial cells are recently highlighted as an important regulator of inflammation in this disease. This in vitro study was established to investigate the effect of 1,25D3 on key proinflammatory cytokine IL-6 production and aryl hydrocarbon receptor (AhR)/nuclear factor-κB (NF-κB) signaling in oral epithelial cells upon the stimulation of lipopolysaccharide (LPS) from periodontal pathogens.

Methods

OKF6/TERT-2 oral keratinocytes were incubated with LPS and different concentrations of 1,25D3, and levels of IL-6 production were determined using enzyme-linked immunosorbent assay (ELISA). Expression of vitamin D receptor (VDR), and activation of AhR was examined using western blot analysis, and phosphorylation of NF-κB was detected using cell-based protein phosphorylation ELISA.

Results

1,25D3 inhibited LPS-induced IL-6 overexpression in OKF6/TERT-2 cells. Additionally, 1,25D3 increased VDR expression and AhR activation, and repressed NF-κB phosphorylation. Furthermore, 1,25D3 suppressed IL-6 expression and enhanced VDR expression and regulated AhR/NF-κB signaling activation in a dose-dependent manner after 48 h treatment.

Conclusions

These results suggest that 1,25D3 may inhibit LPS-induced IL-6 overexpression in human oral epithelial cells through AhR/NF-κB signaling. Our findings may provide an explanation for the antiinflammatory effect and therapeutic benefit of 1,25D3 in periodontitis.

Effects of 1,25-dihydroxyvitamin D3 on experimental periodontitis and AhR/NF-κB/NLRP3 inflammasome pathway in a mouse model

Vitamin D has been known to have important regulatory functions in inflammation and immune response and shows inhibitory effects on experimental periodontitis in animal models. However, the potential mechanism has yet to be clarified. Recent studies have highlighted Aryl hydrocarbon receptor (AhR) and its downstream signaling as a crucial regulator of immune homeostasis and inflammatory regulation.

OBJECTIVE

This study aimed to clarify the effect of 1,25-dihydroxyvitamin D3 (VD3) on experimental periodontitis and AhR/nuclear factor-κB (NF-κB)/NLR pyrin domain-containing 3 (NLRP3) inflammasome pathway in the gingival epithelium in a murine model.

METHODOLOGY

We induced periodontitis in male C57BL/6 wild-type mice by oral inoculation of Porphyromonas gingivalis (P. gingivalis), and subsequently gave intraperitoneal VD3 injection to the mice every other day for 8 weeks. Afterwards, we examined the alveolar bone using scanning electron microscopy (SEM) and detected the gingival epithelial protein using western blot analysis and immunohistochemical staining.

RESULTS

SEM images demonstrated that alveolar bone loss was reduced in the periodontitis mouse model after VD3 supplementation. Western blot analyses and immunohistochemical staining of the gingival epithelium showed that the expression of vitamin D receptor, AhR and its downstream cytochrome P450 1A1 were enhanced upon VD3 application. Additionally, VD3 decreased NF-κB p65 phosphorylation, and NLRP3, apoptosis-associated speck-like protein, caspase-1, interleukin-1β (IL-1β) and IL-6 protein expression.

CONCLUSIONS

These results implicate the alleviation of periodontitis and the alteration of AhR/NF-κB/NLRP3 inflammasome pathway by VD3 in the mouse model. The attenuation of this periodontal disease may correlate with the regulation of AhR/NF-κB/NLRP3 inflammasome pathway by VD3.

Activation of vitamin D in the gingival epithelium and its role in gingival inflammation and alveolar bone loss

BACKGROUND AND OBJECTIVE

Both chronic and aggressive periodontal disease are associated with vitamin D deficiency. The active form of vitamin D, 1,25(OH)₂ D₃ , induces the expression of the antimicrobial peptide LL-37 and innate immune mediators in cultured human gingival epithelial cells (GECs). The aim of this study was to further delineate the mechanism by which vitamin D enhances the innate defense against the development of periodontal disease (PD).

MATERIALS AND METHODS

Wild-type C57Bl/6 mice were made deficient in vitamin D by dietary restriction. Cultured primary and immortalized GEC were stimulated with 1,25(OH)₂ D₃ , followed by infection with Porphyromonas gingivalis, and viable intracellular bacteria were quantified. Conversion of vitamin D₃ to 25(OH)D₃ and 1,25(OH)₂ D₃ was quantified by ELISA. Effect of vitamin D on basal IL-1α expression in mice was determined by topical administration to the gingiva of wild-type mice, followed by qRT-PCR.

RESULTS

Dietary restriction of vitamin D led to alveolar bone loss and increased inflammation in the gingiva in the mouse model. In primary human GEC and established human cell lines, treatment of GEC with 1,25(OH)₂ D₃ inhibited the intracellular growth of P. gingivalis. Cultured GEC expressed two 25-hydroxylases (CYP27A1 and CYP2R1), as well as 1-α hydroxylase, enabling conversion of vitamin D to both 25(OH)D₃ and 1,25(OH)₂ D₃ . Topical application of both vitamin D₃ and 1,25(OH)₂ D₃ to the gingiva of mice led to rapid inhibition of IL-1α expression, a prominent pro-inflammatory cytokine associated with inflammation, which also exhibited more than a 2-fold decrease from basal levels in OKF6/TERT1 cells upon 1,25(OH)₂ D₃ treatment, as determined by RNA-seq.

CONCLUSION

Vitamin D deficiency in mice contributes to PD, recapitulating the association seen in humans, and provides a unique model to study the development of PD. Vitamin D increases the activity of GEC against the invasion of periodontal pathogens and inhibits the inflammatory response, both in vitro and in vivo. GEC can convert inactive vitamin D to the active form in situ, supporting the hypothesis that vitamin D can be applied directly to the gingiva to prevent or treat periodontal disease.

Serum vitamin D levels and chronic periodontitis in adult, Caucasian population-a systematic review

The aim of this systematic review was to explore the relationship between serum vitamin D levels and periodontal disease. The review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The focused PICO question was: Are serum vitamin D levels (I) associated with gingivitis or periodontitis (C) in healthy humans (P)? PubMed (Medline), Embase, Science Direct, the Cochrane library, and grey literature were searched up to 31 July 2017. Two reviewers independently selected studies and extracted data. Quality, risk of bias, and heterogeneity of the studies were assessed using the Newcastle-Ottawa Scale. In total, 365 studies were identified and 24 were analyzed. Seven studies fulfilled the inclusion criteria. Four case-control studies showed an influence of vitamin D and its metabolites on periodontal health status/disease. One interventional study suggested the proposed anti-inflammatory role of vitamin D. Two cross-sectional studies failed to show a relationship between vitamin D and periodontal condition. The literature on the effect of serum vitamin D levels on periodontal status remains scarce and controversial. Some data, however, support a "perio-protective" role for vitamin D. There is a need for well-designed randomized clinical trials to explore the possible anti-inflammatory effect of vitamin D on periodontal health.

Vitamin D levels and risk for periodontal disease: A systematic review

OBJECTIVE

To evaluate the existing evidence supporting or refuting the following questions: (i) Do patients with lower vitamin D levels have higher risk for periodontal disease? (ii) Are periodontal treatment outcomes improved by the adjuvant supplementation of vitamin D or by elevated serum vitamin D levels?

MATERIAL AND METHODS

MEDLINE, SCOPUS, EMBASE and Cochrane Central Register of Controlled Trials (CENTRAL) databases were searched up to September 2017. Studies were included if they had measured serum vitamin D levels or vitamin D intake and any periodontal parameter.

RESULTS

Overall, 27 studies were included (13 cross-sectional studies, 6 case-control studies, 5 cohort studies, 2 randomized clinical trials and 1 case series study). Sixty-five percent of the cross-sectional studies reported significant associations between low vitamin D levels and poor periodontal parameters. None of the observational longitudinal studies found that periodontal disease progression could be attributed to lower vitamin D levels. No interventional studies that evaluated the use of vitamin D supplementation as a solely adjuvant to periodontal treatment was found. No meta-analysis was performed due to high variability across studies.

CONCLUSION

The data to support or refute the association between vitamin D levels and periodontal disease are inconclusive at the moment. More rigorously designed longitudinal studies with standardized definitions of periodontal disease and vitamin D are necessary.

The Role of Nutrition in Periodontal Health: An Update

Periodontal health is influenced by a number of factors such as oral hygiene, genetic and epigenetic factors, systemic health, and nutrition. Many studies have observed that a balanced diet has an essential role in maintaining periodontal health. Additionally, the influences of nutritional supplements and dietary components have been known to affect healing after periodontal surgery. Studies have attempted to find a correlation between tooth loss, periodontal health, and nutrition. Moreover, bone formation and periodontal regeneration are also affected by numerous vitamins, minerals, and trace elements. The aim of this review is to critically appraise the currently available data on diet and maintenance of periodontal health and periodontal healing. The effects of nutritional intervention studies to improve the quality of life and well-being of patients with periodontal disease have been discussed.

Higher Intakes of Fruits and Vegetables, β-Carotene, Vitamin C, α-Tocopherol, EPA, and DHA Are Positively Associated with Periodontal Healing after Nonsurgical Periodontal Therapy in Nonsmokers but Not in Smokers

BACKGROUND

Periodontitis is a chronic inflammatory disease and a significant risk factor for tooth loss. Although a link between diet and periodontal health exists, the relation between diet and healing after periodontal therapy has yet to be investigated.

OBJECTIVE

The objective was to determine whether higher intakes of fruits and vegetables or nutrients with antioxidant or anti-inflammatory activity are associated with greater healing, measured as reduced probing depth (PD), after scaling and root planing (SRP), a cost-effective treatment to manage periodontal disease and prevent tooth loss.

METHODS

Patients (63 nonsmokers, 23 smokers) with chronic generalized periodontitis who were undergoing SRP participated. Healing was evaluated based on PD, assessed at baseline and 8-16 wk after SRP. Intakes of fruits, vegetables, β-carotene, vitamin C, α-tocopherol, α-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) were estimated using the Block 2005 food frequency questionnaire and a supplement questionnaire. Serum 25-hydroxyvitamin D concentrations were also measured. PD (% sites >3 mm) was modeled in multiple linear regression and analysis of covariance by tertile of intake and adjusted for age, sex, body mass index (BMI), baseline PD, examiner, gingival bleeding, and study duration.

RESULTS

In nonsmokers, PD was associated with fruit and vegetable, β-carotene, vitamin C, α-tocopherol, EPA, and DHA intakes (P < 0.05). PD was not significantly associated with ALA intake or serum 25-hydroxyvitamin D concentration. Significant associations that included supplements (β-carotene, vitamin C, α-tocopherol) were attenuated or lost, depending on the statistical model used. There were no significant associations within the group of smokers.

CONCLUSIONS

Dietary intakes of fruits and vegetables, β-carotene, vitamin C, α-tocopherol, EPA, and DHA are associated with reduced PD after SRP in nonsmokers, but not smokers, with chronic generalized periodontitis. These findings may lead to the development of dietary strategies to optimize healing after periodontal procedures. This trial was registered at clinicaltrials.gov as NCT02291835.