The directional and non-directional associations of periodontitis with chronic kidney disease: A systematic review and meta-analysis of observational studies.

This systematic review aimed to assess the current evidence on the directional and non-directional associations of periodontitis with chronic kidney disease (CKD). Electronic search for observational studies on the association of periodontitis with CKD was performed in MEDLINE, EMBASE, PubMed, Open GREY and Cochrane library up to June 5, 2017. Two reviewers conducted study selection, data collection and assessment of methodological quality using the original and modified Newcastle-Ottawa Scale. Cohort, case-control and cross-sectional studies were included, which clearly defined periodontitis and CKD or reported acceptable clinical parameters of these 2 diseases in adults. Meta-analysis was employed to estimate the pooled odds ratio on the non-directional association and the incidence rate ratio (IRR) for the directional association. Among 2530 potential eligible articles, 47 were finally included. Most of them investigated a non-directional association of periodontitis with CKD, including 7 case-control studies and 38 cross-sectional studies; 24 studies had statistical analysis on the non-directional association and 75% of them reported significant results, which were supported further by the meta-analysis (random: odds ratio = 2.12, P < .001; χ2  = 25.74, I2  = 88.3%). None of the studies focused on the directional association of CKD (as the exposure) with periodontitis (as the outcome), whereas 2 retrospective cohort studies explored a directional association of periodontitis (as the exposure) with CKD (as the outcome) (random: IRR=2.10, P > .05; fixed: IRR=1.76, P < .05; χ2  = 4.65, I2  = 78.3%). Overall, the high heterogeneity of studies limits the significance of these results. There is substantial evidence on the non-directional association of periodontitis with CKD, while there are limited studies on the directional association. Well-designed prospective studies with longer follow-ups in representative communities are needed to clarify the directional association and enhance the quality of the evidence on this topic.

The gingival biotype in a cohort of Chinese subjects with and without history of periodontal disease.

OBJECTIVE: The present study aimed to determine the gingival biotype in Chinese subjects with and without a history of periodontal disease. MATERIAL AND METHODS: Thirty periodontally healthy subjects and 20 subjects with treated chronic periodontitis were recruited. The mid-buccal gingival thickness of upper central and lateral incisors was measured by a customized caliper in all subjects. The crown length and crown width of these teeth were recorded in the healthy group, while gingival recession was measured in the periodontitis group. These outcome measures were compared among the groups and sub-groups, and the correlation of gingival biotypes with clinical parameters was analyzed. RESULTS: The mean thickness of gingiva in the 30 periodontally healthy subjects was 1.05±0.31 mm (0.47-1.57 mm). The males exhibited a greater crown length than the females (P<.05). No significant correlation was found between gingival thickness and the crown width to crown length ratio. The mean gingival thickness at the 80 sites measured in the 20 periodontitis subjects was 0.89±0.29 mm (0.33-1.56 mm). Overall, gingival biotype as measured by gingival thickness was significantly correlated with gingival recession (r=-.240, P=.032), while a stronger correlation was found among the 42 sites with bleeding on probing prior to periodontal treatment (r=-.382, P=.013). CONCLUSION: This study shows that gingival biotype measured by gingival thickness in subjects with treated periodontitis is significantly correlated with gingival recession. Further study could clarify the clinical implications of gingival biotype in the management of periodontal patients.

Lipid subclasses profiles and oxidative stress in aggressive periodontitis before and after treatment.

BACKGROUND AND OBJECTIVE: Associations between dyslipidaemia, oxidative stress and periodontitis have emerged in recent years. However, there is a lack of studies investigating these associations in aggressive periodontitis (AgP) cases. The aim of this study was to investigate the lipid and oxidative stress profiles in patients with AgP, and to relate them to clinical variables and interleukin (IL)-6 genetic variants. MATERIAL AND METHODS: Twelve non-smoking Caucasian patients with AgP selected based on their IL6 haplotypes underwent periodontal non-surgical and surgical treatment. Peripheral blood samples taken at baseline and at six different time-points after treatment were processed to determine IL-6 circulating levels, lipid profiles (cholesterol, triglycerides, high-density lipoprotein [HDL] and low-density lipoprotein [LDL] subclasses) and oxidative stress markers (glutathione and total lipid hydroperoxide levels). RESULTS: HDLs were the most prevalent lipoproteins, followed by intermediate-density lipoprotein, very-low-density lipoprotein and LDL. The LDL subclasses consisted mainly of the less atherogenic large LDL. The lipid profile did not consistently change after treatment up to 3 mo after surgery. Periodontal disease severity was associated with LDL levels and size. The IL6 haplotypes were associated with total cholesterol, triglycerides, HDL and LDL subclasses after adjusting for confounders. IL-6 circulating levels were associated with both very-low-density lipoprotein and lipid hydroperoxide levels. CONCLUSION: Based on these data, we conclude that both periodontal disease severity and IL6 haplotypes may influence lipid profiles in AgP.

Influence of IL-6 haplotypes on clinical and inflammatory response in aggressive periodontitis.

OBJECTIVES: The aim of this study was to investigate the inflammatory response in aggressive periodontitis (AgP) patients after periodontal therapy and associate these changes to subjects' interleukin-6 (IL-6) genetic variants. MATERIALS AND METHODS: Twelve non-smoking UK Caucasian patients with AgP were selected based on their IL6 haplotypes (six haplotype positive and six haplotype negative based on polymorphisms rs 2069827 and rs 2069825) and underwent full mouth non-surgical periodontal therapy, followed by open flap surgery. Gingival crevicular fluid (GCF) and peripheral blood samples were taken at baseline and at six different time points after treatment. Gingival biopsy samples were harvested during surgery and underwent immunohistochemical analysis for identification of IL-6. RESULTS: An overall improvement in clinical periodontal parameters was observed following periodontal therapy. Haplotype status was associated with clinical presentation, Aggregatibacter actinomycetemcomitans counts in subgingival plaque samples, white cell count, neutrophils, red cell count and haemoglobin. GCF IL-6 concentrations increased dramatically 1 day after surgery and IL-6 haplotype-positive subjects exhibited a higher magnitude in this increase. CONCLUSIONS: IL6 haplotypes may have an effect on clinical presentation and magnitude and kinetics of local and systemic inflammatory responses following non-surgical and surgical periodontal therapy in aggressive periodontitis. CLINICAL RELEVANCE: Detecting IL-6 haplotype-positive periodontitis patients might become helpful in identifying subjects prone to excessive inflammatory response and increased periodontal breakdown.