Baseline HbA1c Level Influences the Effect of Periodontal Therapy on Glycemic Control in People with Type 2 Diabetes and Periodontitis: A Systematic Review on Randomized Controlled Trails

The efficacy of combining adjuvants with non-surgical periodontal therapy in individuals with type 2 diabetes: A Bayesian network meta-analysis

AIM

This Bayesian network meta-analysis of randomized controlled trials assessed the effect of adjuvant periodontal treatment in both periodontal and HbA1c outcomes in adult individuals with type 2 diabetes (T2DM).

MATERIALS AND METHODS

A systematic search was done up to February 2023 comparing sub-gingival debridement (SD) in combination with local or systemic adjuvant treatment with SD alone for individuals with T2DM. The primary outcomes were changes in absolute HbA1c levels and full-mouth probing depth reported at 3- to 6-month post-treatment.

RESULTS

Seventy-two eligible publications evaluating 27 adjuvant treatments were retrieved. The combination of SD and systemic antibiotic metronidazole or SD and antioxidant alpha lipoic acid provided, respectively, 1.4% (95% credible interval [CrI] 0.48; 2.20) and 2.4% (95% CrI 1.50; 3.30) more significant improvement on HbA1c levels, and 0.89 mm (95% CrI 0.23; 1.50) and 0.92 mm (95% CrI 0.02; 0.92) greater periodontal probing depth reductions. Other adjuvant treatments provided added benefit to the periodontal outcomes without discernible effects on HbA1c.

CONCLUSIONS

Adjuvant use of metronidazole or alpha lipoic acid was the best adjunct option to provide clinically meaningful HbA1c levels and probing depth reductions. However, no strong recommendation can be drawn due to the scarcity of studies for each adjuvant treatment and the low certainty of the resultant evidence.

Effect of periodontal therapy on glycaemic control in type 2 diabetes

AIM

This study aimed to elucidate the impact of periodontal therapy on glycaemic control in individuals with type 2 diabetes and various baseline blood glucose levels using a large-scale claims database from Japan.

MATERIALS AND METHODS

Using the JMDC Claims Database, we identified individuals with type 2 diabetes who underwent health check-ups in the fiscal years 2018 or 2019 and were followed up until the next year's health check-up. We conducted a weighted cohort analysis using stabilized inverse probability weights for treatment and censoring to estimate the effect of periodontal therapy on changes in haemoglobin A1c levels within a year. Analysis was done for different baseline haemoglobin A1c categories: 6.5%-6.9%, 7.0%-7.9% and ≥8.0%.

RESULTS

Of the 4279 insured persons included in the study, 957 received periodontal therapy. Overall, there was a tendency towards improved glycaemic control among those who received periodontal therapy. Participants with baseline haemoglobin A1c levels of 7.0%-7.9% who received periodontal therapy exhibited significantly better glycaemic control compared with those without dental visits (difference; -0.094 [95% confidence interval: -0.181 to -0.007]).

CONCLUSIONS

Periodontal therapy may improve glycaemic control in individuals with diabetes, especially in those with haemoglobin A1c levels ≥7.0%.

Current scientific evidence for why periodontitis should be included in diabetes management

This Perspective provides a brief summary of the scientific evidence for the two-way links between periodontal diseases and hyperglycemia (diabetes mellitus [DM] and pre-DM). It delivers in a nutshell current scientific evidence for manifestations of hyperglycemia on periodontal health status and effects of periodontal diseases on blood glucose levels and in turn incidence, progression, and complications of diabetes. Of outmost importance is presentation of scientific evidence for the potential of routine periodontal treatment to lower blood glucose levels, providing a novel, economical tool in DM management. Non-surgical periodontal treatment ("deep cleaning") can be provided by dental hygienists or dentists in general dental offices, although severe cases should be referred to specialists. Such therapy can decrease the costs of DM care and other health care costs for people with DM. The great importance of a healthy oral cavity free of infection and subsequent inflammation - especially periodontitis that if untreated will cause loosening and eventually loss of affected teeth - has largely gone unnoticed by the medical community as the health care curricula are largely void of content regarding the bi-directional links between oral health and systemic health, despite elevation of blood glucose levels being an integral part of the general systemic inflammation response. The importance of keeping disease-free, natural teeth for proper biting and chewing, smiling, self-esteem, and pain avoidance cannot be overestimated. Medical and dental professionals are strongly encouraged to collaborate in patient-centered care for their mutual patients with - or at risk for - hyperglycemia.

Salivary Proteome and Intact N-Glycopeptides Analysis Reveal Specific Signatures in Periodontitis

Periodontitis is a prevalent oral inflammatory disease that can result in tooth loss and is closely linked to type 2 diabetes (T2D). In this study, we analyzed the salivary proteome and intact N-glycopeptides (IGPs) of individuals with mild-moderate, severe, aggressive periodontitis, and periodontitis with T2D, including those treated with antidiabetic drugs, to identify specific signatures associated with the disease. Our results revealed that salivary proteins and glycoproteins were altered in all periodontitis groups (PRIDE ID: 1-20230612-72345), with fucose- and sialic acid-containing N-glycans showing the greatest increase. Additionally, differentially expressed proteins were classified into 9 clusters, including those that were increased in all periodontitis groups and those that were only altered in certain types of periodontitis. Interestingly, treatment with antidiabetic drugs reversed many of the changes observed in the salivary proteome and IGPs in T2D-related periodontitis, suggesting a potential therapeutic approach for managing periodontitis in patients with T2D. Consistent with MS/MS results, the expression of salivary IGHA2 and Fucα1-3/6GlcNAc (AAL) was significantly increased in MP. These findings provide new insights into the pathogenesis of periodontitis and highlight the potential of salivary biomarkers for diagnosis, prognosis, and monitoring of disease progression and treatment response.

Systemic antibiotics adjuvants to scaling and root planing in type 2 diabetic and periodontitis individuals: Systematic review with network meta-analysis

Targeting inflammatory pathways is considered a common strategy to control type 2 diabetes (T2D) and periodontitis. This overview was to validate systemic antibiotics as an adjuvant to scaling and root planing (SRP) for the treatments of periodontal patients with T2D. Literature searches were conducted using Web of Science, PubMed, Cochrane, and EMBASE. Randomized trials comparing SRP and systemic antibiotics on glycated hemoglobin (HbA1c) and probing pocket depth (PPD) in adults with T2D and periodontitis were analyzed using network meta-analysis and meta-regression. At 3-month postintervention, meta-analyses of 16 studies revealed that SRP and SRP plus systemic antibiotics (SRPa) had similar significant effects in reducing HbA1c levels of - 0.72% and - 0.96% respectively. While SRP and SRPa also, respectively, reduced PPD of - 0.67 and - 0.89 mm, SRPa showed a better reduction than SRP. At 6-month postintervention, meta-analyses of 7 trials revealed that only SRP was effective in reducing HbA1c levels (-0.29%) but not SRPa. Although both SRP and SRPa still significantly reduced PPD by - 0.56 and - 0.81 mm, respectively, there was no difference between them. The current overview suggested that routine SRP alone is highly recommended for patients with T2D and periodontitis, since systemic antibiotics as an adjuvant provide a rather short-term effect.

Association between uncontrolled diabetes and periodontal disease in US adults: NHANES 2009-2014

This study examined the relationship between uncontrolled diabetes and periodontal disease (PD) among adults in the United States. We used data from the 2009-2014 National Health and Nutrition Examination Survey (NHANES) with a sample of 6108 adults ages 30 and over. To measure PD status, we used the Centers for Disease Control and Prevention/American Academy of Periodontology's standards. To classify DM status (no DM, DM with HbA1c < 9%, diabetes with HbA1c ≥ 9%),we used self-reported Diabetes Mellitus (DM) diagnosis and laboratory report of HbA1c. Approximately 8.5% of the sample had controlled DM, and 1.7% had uncontrolled DM, for a total of 10.2% DM in the analysis. Multivariate logistic regression showed that compared to those without DM, PD was significantly increased with controlled DM (adjusted odds ratio (aOR) = 1.32, 95% confidence interval (CI) 1.01-1.73, p < 0.05) and even more with uncontrolled DM (aOR = 2.48, 95% CI 1.52-4.04, p < 0.001), after adjusting for covariates. Factors that reduced the prevalence of PD included annual dental visits, female gender, and college education. Factors that significantly increased PD prevalence were cigarette smoking, non-white race, income < 200% Federal Poverty Level, and older age (age > 50 years). In conclusion, uncontrolled DM was significantly associated with higher odds of PD among adults in the US.

Effects of Tocotrienol-Rich Fraction Supplementation in Patients with Type 2 Diabetes: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

There are a large number of studies that have reported benefits of tocotrienol-rich fraction (TRF) in various populations with different health status. To date, no systematic reviews have examined randomized controlled trials (RCTs) on the effect of TRF supplementations specifically in patients with type 2 diabetes mellitus (T2DM). This systematic review and meta-analysis aim to examine the changes in HbA1c (glycated hemoglobin), blood pressure, and serum Hs-CRP (C-reactive protein high sensitivity) levels at post-TRF supplementation. Online databases including PubMed, Scopus, OVID Medline, and Cochrane Central Register of Controlled Trials were searched from inception until March 2023 for RCTs supplementing TRF in patients with T2DM. A total of 10 studies were included in the meta-analysis to estimate the pooled effect size. The Cochrane Risk-of-Bias (RoB) Assessment Tool was utilized to evaluate the RoB in individual studies. The meta-analysis revealed that TRF supplementation at a dosage of 250-400 mg significantly decreased HbA1c (-0.23, 95% CI: -0.44, -0.02, P < 0.05, n = 754), particularly where the intervention duration is less than 6 mo (-0.47%, 95% CI: -0.90, -0.05, P < 0.05, n = 126) and where duration of diabetes is less than 10 y (-0.37, 95% CI: -0.68, -0.07, P < 0.05, n = 83). There was no significant reduction in systolic and diastolic blood pressure and serum Hs-CRP (P > 0.05). The present meta-analysis demonstrated that supplementing with TRF in patients with T2DM decreased HbA1c but does not decrease systolic and diastolic blood pressure and serum Hs-CRP.

Diabetes mellitus promotes susceptibility to periodontitis-novel insight into the molecular mechanisms

Diabetes mellitus is a main risk factor for periodontitis, but until now, the underlying molecular mechanisms remain unclear. Diabetes can increase the pathogenicity of the periodontal microbiota and the inflammatory/host immune response of the periodontium. Hyperglycemia induces reactive oxygen species (ROS) production and enhances oxidative stress (OS), exacerbating periodontal tissue destruction. Furthermore, the alveolar bone resorption damage and the epigenetic changes in periodontal tissue induced by diabetes may also contribute to periodontitis. We will review the latest clinical data on the evidence of diabetes promoting the susceptibility of periodontitis from epidemiological, molecular mechanistic, and potential therapeutic targets and discuss the possible molecular mechanistic targets, focusing in particular on novel data on inflammatory/host immune response and OS. Understanding the intertwined pathogenesis of diabetes mellitus and periodontitis can explain the cross-interference between endocrine metabolic and inflammatory diseases better, provide a theoretical basis for new systemic holistic treatment, and promote interprofessional collaboration between endocrine physicians and dentists.

Effect of subgingival periodontal therapy on glycaemic control in type 2 diabetes patients: Meta-analysis and meta-regression of 6-month follow-up randomized clinical trials

BACKGROUND

Periodontitis worsens the hyperglycaemia in patients with type 2 diabetes mellitus (T2DM). Subgingival instrumentation, with or without surgical access, is the gold-standard treatment for periodontitis. The aim was to summarize the evidence on the effect of subgingival instrumentation (with or without open flap) on the reduction of glycosylated haemoglobin (HbA1c).

METHODS

Nine electronic databases were searched up to 15 February 2023. Twelve randomized controlled trials with at least 6 months of follow-up were included. Studies using systemic or local-delivery antimicrobial therapies were excluded. Meta-analyses were performed using the random-effects model. The sources of heterogeneity were assessed by applying linear meta-regression. Risk of bias was assessed by RoB 2, and certainty of evidence by GRADE.

RESULTS

Eleven studies were included in the quantitative analyses (1374 patients). Subgingival instrumentation resulted in 0.29% lower HbA1c (95% confidence interval: 0.10-0.47; p = .03) compared with non-active treatment.

DISCUSSION

None of the 12 studies were assessed as having low risk of bias. The percentage of females and the time of diabetes diagnosis significantly explained the high level of heterogeneity. Subgingival periodontal therapy results in a significant and clinically relevant improvement in glycaemic control over 6 months in patients with T2DM and periodontitis. The grade of evidence was moderate.

Sodium alginate-based drug delivery for diabetes management: A review

Diabetes mellitus (DM) is among the biggest global health problems of the 21st century, which is characterised by insufficient insulin secretion and results in the augmentation of blood sugar levels. The current foundation of hyperglycemia therapy is oral antihyperglycemic medications like biguanides, sulphonylureas, α-glucosidase inhibitors, peroxisome proliferator-activated receptor gamma (PPAR-γ) agonists, sodium-glucose co-transporter 2 (SGLT-2) inhibitors, dipeptidyl peptidase-4 (DPP-4) inhibitors and others. Many naturally occurring substances have shown promise in treating hyperglycemia. Inadequate prologitivity of action, restricted bioavailability, site specificity, and dose-related side effects are some problems with currently available anti-diabetic medications. Sodium alginate has shown promise as a drug delivery mechanism, potentially solving issues with current therapies for several substances. This review summarizes the research on the efficacy of drug delivery systems based on alginate for transporting oral hypoglycemic medicines, phytochemicals, and insulin for treating hyperglycemia.

Effect of periodontal therapy on insulin resistance in adults with dysglycemia and periodontitis: a systematic review and meta-analysis

OBJECTIVES

This systematic review and meta-analysis aimed to address whether non-surgical periodontal therapy (NSPT) can affect insulin resistance, estimated by the homeostasis model assessment (HOMA), in adults with prediabetes or type 2 diabetes mellitus and periodontitis.

MATERIALS AND METHODS

Six electronic databases and the gray literature were systematically searched for interventional studies reporting NSPT effect on insulin resistance. Seven studies met the eligibility criteria to be synthesized in the qualitative analysis, six reporting change in HOMA-IR, three reporting change in HOMA-%S, and two in HOMA-β. Among them, four were pooled in a meta-analysis of standardized mean difference (SMD) of HOMA-IR; comparing pre- and post-intervention values, three were pooled considering HOMA-%S as outcome, and two studies were summarized considering SMD of HOMA-%S between intervention and control groups. HOMA-β results were qualitatively synthetized.

RESULTS

With low level of certainty, NSPT significantly reduced HOMA-IR, when compared with pre-intervention data (SMD, -0.35, 95% CI -0.63 to 0.07, p=0.02). There were no significant changes in HOMA-%S or in HOMA-β scores. The level of certainty was very low and moderate, respectively.

CONCLUSIONS

Assertions about a causal link between NSPT and insulin resistance are weak and conflicting, although our more robust results point out to the absence of effect. .

CLINICAL RELEVANCE

Because further high-quality studies assessing the relationship between periodontitis and insulin resistance are need, the findings of the current systematic review are limited to give recommendations for clinicians. However, while identifying a lack of research in humans with T2D concerning periodontitis and insulin resistance, this study reinforces the need of multicenter well-designed randomized clinical trials.

Effect of periodontal treatment on glycated haemoglobin and metabolic syndrome parameters: A randomized clinical trial

AIM

To assess the effect of periodontal treatment on HbA1c and diagnostic parameters of patients with metabolic syndrome (MetS).

MATERIALS AND METHODS

One hundred and fifty-eight patients with MetS and moderate and severe periodontitis were included. They were randomized into a test group (n = 79), which received non-surgical periodontal treatment, and a control group (n = 79), which received no treatment. Medical treatment was delivered to both groups. Clinical periodontal, anthropometric and serological parameters were assessed at baseline, 3 and 6 months. The main outcome was glycated haemoglobin (HbA1c) levels, and the secondary outcomes were changes in the MetS parameters, C-reactive protein (CRP) and HOMA indexes.

RESULTS

Significant reductions in all periodontal parameters were observed in the test group, compared with the control group, at 3 and 6 months (p < .001). HbA1c levels, MetS parameters, CRP and HOMA indexes showed no significant differences between the test group and the control group at 3 and 6 months.

CONCLUSIONS

Periodontal treatment led to a substantial reduction in periodontal inflammation, although there was no significant effect on the parameters used for MetS diagnosis in patients with early diagnosed and well-controlled MetS.

Effectiveness of periodontal treatment to improve glycemic control: an umbrella review

AIM

The aim of the present umbrella review was to systematically assess existing evidence on the effect of non-surgical periodontal therapy, both per se' and with adjuvants, on glycemic control in patients with type 2 diabetes and periodontitis and to combine quantitative data with a meta-analysis.

MATERIALS AND METHODS

A detailed study protocol was registered on PROSPERO (CRD42021222279). Four electronic databases (Medline via Pubmed, EMBASE, Cochrane Database of Systematic Reviews and Scielo) were searched independently and in duplicate to identify potentially eligible systematic reviews up to March 2022. Two pre-calibrated independent reviewers performed study selection, data extraction and quality assessment with two checklists (AMSTAR 2 and PRISMA). Moreover, general characteristics of primary studies included in each systematic review were abstracted, and JADAD scale was used to assess the risk of bias for included randomized controlled trials. Data from the individual studies included in each meta-analysis were analyzed, using both fixed and random effect model. The statistical heterogeneity was calculated using the Q test and the I² index. The publication bias was evaluated using a funnel plot and Egger's linear regression method.

RESULTS

Sixteen systematic reviews, published between 2010 and 2021, were included for qualitative synthesis. From these systematic reviews, a total of 27 studies were included in the meta-analysis: all of them were randomized clinical trials, except 1 controlled clinical study. A statistically significant mean difference of - 0.49% and of - 0.38% HbA1c reductions was seen respectively at 3- and 6-month post-treatment, favoring the treatment group (non-surgical periodontal therapy alone) compared to the control group (no treatment). The effect of periodontal treatment with the adjunctive use of antibiotics or laser on the glycemic control was not statistically significant compared to non-surgical periodontal therapy alone.

CONCLUSIONS

The findings of the present study, within its limitations, indicated that non-surgical treatment of periodontitis is an efficacious therapy for improving the glycemic control in type 2 diabetes mellitus patients, both at 3- and 6-month follow-up.

Effects of Nonsurgical Periodontal Therapy on Salivary 8-Hydroxy-Deoxyguanosine Levels and Glycemic Control in Diabetes Mellitus Type 2 Patients

Diabetes and periodontitis are complex chronic diseases that are potentially interrelated, as well as associated with oxidative stress. Thus, the aim of the present study was to evaluate the influence of nonsurgical periodontal treatment on salivary 8-hydroxy-deoxyguanosine (8-OHdG) levels and glycemic control in patients suffering from both diabetes mellitus type 2 (DM2) and periodontitis. The study sample included 53 DM2 patients, while 31 systemically healthy patients served as controls. Participants in both groups suffered from periodontitis of comparable severity. Periodontal clinical parameters, namely plaque index (PI), gingival index (GI), papilla bleeding index (PBI), probing pocket depth (PPD), and clinical attachment level (CAL) were recorded, along with salivary 8-OHdG levels and glycated hemoglobin (HbA1c). Levels of 8-OHdG were analyzed by ELISA. All aforementioned parameters were evaluated prior to commencing the study and at 90-day follow-up upon nonsurgical periodontal therapy completion. At baseline, salivary levels of 8-OHdG in DM2 patients were significantly higher (1.17 ng/mL) than those measured for the control group (0.75 ng/mL) and showed significant positive correlation with GI and PPD (p < 0.05). Three months after nonsurgical periodontal therapy, the salivary 8-OHdG levels were significantly reduced in DM2 patients (p < 0.05). Analysis results also revealed statistically significant changes in all measured clinical parameters between baseline and three-month follow-up in both groups (p < 0.05). Upon treatment completion, a decline in the HbA1c level was noted in DM group, but it did not reach statistical significance (p > 0.05). It can be concluded that DM2 patients benefit from non-surgical periodontal therapy, as indicated by a marked reduction in their salivary 8-OHdG level and a modest improvement in glycemic control. Short-term clinical benefits noted in the DM group were similar to those observed in the non-diabetic periodontal patients.

Screening for type 2 diabetes and periodontitis patients (CODAPT-My©): a multidisciplinary care approach

BACKGROUND

The practice of referring diabetic patients for dental intervention has been poor despite awareness and knowledge of the oral health effects of diabetes. Likewise, dentists treating patients receiving diabetes treatment are rarely updated on the glycaemic status and as a result, the opportunity for shared management of these patients is missed. This study aimed to provide a standardised care pathway which will initiate screening for diabetes from dental clinics and link patients with primary care for them to receive optimised care for glycaemic control.

METHOD

A Modified Delphi technique was employed to obtain consensus on recommendations, based on current evidence and best care practices to screen for diabetes among patients attending dental clinics for periodontitis. Expert panel members were recruited using snowball technique where the experts comprised Family Medicine Specialists (5), Periodontists (6), Endocrinologists (3) and Clinical Pharmacists (4) who are involved in management of patients with diabetes at public and private healthcare facilities. Care algorithms were designed based on existing public healthcare services.

RESULTS

The CODAPT^© panel recommends referral to primary care for further evaluation of glycaemic status if patients diagnosed with periodontitis record fasting capillary blood glucose levels ≥ 5.6 mmol/L. Intervention treatment options for prediabetes are listed, and emphasis on feedback to the dental healthcare team is outlined specifically.

CONCLUSION

The CODAPT^© care pathway has the potential to link dental clinics with primary care for diagnosis and/or optimised treatment of prediabetes/diabetes among patients receiving periodontitis treatment.

Antioxidant Effects of Curcumin Gel in Experimental Induced Diabetes and Periodontitis in Rats

This study aimed to evaluate the effect of curcumin gel on antioxidant marker level in experimental induced diabetes and periodontitis (EDP) in rats. Adult Wistar rats were randomized into five groups (20 each): (1) EDP treated with scaling and root planing (SRP) + curcumin gel (CU), (2) EDP treated with CU, (3) EDP treated with SRP, (4) EDP without treatment, and (5) systemically healthy and without ligature (control). Each group was subdivided equally into 4 subgroups of 5 rats. Diabetes was induced by intraperitoneal injection of streptozotocin (STZ), and periodontitis was induced by a ligature. Blood samples were collected by cardiac puncture at 0, 7, 14, and 21 days to assess oxidative stress of malondialdehyde (MDA) and antioxidant enzymes of glutathione peroxidase (GPx), catalase (CAT), and suproxidase dismutase (SOD) levels. The results showed a significant increase in serum MDA and antioxidant enzyme levels in the untreated EDP group compared to the control group ( $p<0.05$ ). The adjuvant use of CU to SRP resulted in a significant reduction of MDA and CAT levels as compared to the SRP group ( $p<0.05$ ); however, significant reduction of GPX and SOD levels can be found only at day 7. It can be concluded that the decreased level of antioxidant enzymes can be construed as a result of decreased oxidative stress by curcumin therapy.

Treatment of periodontitis for glycaemic control in people with diabetes mellitus

BACKGROUND

Glycaemic control is a key component in diabetes mellitus (diabetes) management. Periodontitis is the inflammation and destruction of the underlying supporting tissues of the teeth. Some studies have suggested a bidirectional relationship between glycaemic control and periodontitis.  Treatment for periodontitis involves subgingival instrumentation, which is the professional removal of plaque, calculus, and debris from below the gumline using hand or ultrasonic instruments. This is known variously as scaling and root planing, mechanical debridement, or non-surgical periodontal treatment. Subgingival instrumentation is sometimes accompanied by local or systemic antimicrobials, and occasionally by surgical intervention to cut away gum tissue when periodontitis is severe. This review is part one of an update of a review published in 2010 and first updated in 2015, and evaluates periodontal treatment versus no intervention or usual care.  OBJECTIVES: To investigate the effects of periodontal treatment on glycaemic control in people with diabetes mellitus and periodontitis.

SEARCH METHODS

An information specialist searched six bibliographic databases up to 7 September 2021 and additional search methods were used to identify published, unpublished, and ongoing studies.  SELECTION CRITERIA: We searched for randomised controlled trials (RCTs) of people with type 1 or type 2 diabetes mellitus and a diagnosis of periodontitis that compared subgingival instrumentation (sometimes with surgical treatment or adjunctive antimicrobial therapy or both) to no active intervention or 'usual care' (oral hygiene instruction, education or support interventions, and/or supragingival scaling (also known as PMPR, professional mechanical plaque removal)). To be included, the RCTs had to have lasted at least 3 months and have measured HbA1c (glycated haemoglobin).

DATA COLLECTION AND ANALYSIS

At least two review authors independently examined the titles and abstracts retrieved by the search, selected the included trials, extracted data from included trials, and assessed included trials for risk of bias. Where necessary and possible, we attempted to contact study authors. Our primary outcome was blood glucose levels measured as glycated (glycosylated) haemoglobin assay (HbA1c), which can be reported as a percentage of total haemoglobin or as millimoles per mole (mmol/mol). Our secondary outcomes included adverse effects, periodontal indices (bleeding on probing, clinical attachment level, gingival index, plaque index, and probing pocket depth), quality of life, cost implications, and diabetic complications.

MAIN RESULTS

We included 35 studies, which randomised 3249 participants to periodontal treatment or control. All studies used a parallel-RCT design and followed up participants for between 3 and 12 months. The studies focused on people with type 2 diabetes, other than one study that included participants with type 1 or type 2 diabetes. Most studies were mixed in terms of whether metabolic control of participants at baseline was good, fair, or poor. Most studies were carried out in secondary care.  We assessed two studies as being at low risk of bias, 14 studies at high risk of bias, and the risk of bias in 19 studies was unclear. We undertook a sensitivity analysis for our primary outcome based on studies at low risk of bias and this supported the main findings. Moderate-certainty evidence from 30 studies (2443 analysed participants) showed an absolute reduction in HbA1c of 0.43% (4.7 mmol/mol) 3 to 4 months after treatment of periodontitis (95% confidence interval (CI) -0.59% to -0.28%; -6.4 mmol/mol to -3.0 mmol/mol). Similarly, after 6 months, we found an absolute reduction in HbA1c of 0.30% (3.3 mmol/mol) (95% CI -0.52% to -0.08%; -5.7 mmol/mol to -0.9 mmol/mol; 12 studies, 1457 participants), and after 12 months, an absolute reduction of 0.50% (5.4 mmol/mol) (95% CI -0.55% to -0.45%; -6.0 mmol/mol to -4.9 mmol/mol; 1 study, 264 participants). Studies that measured adverse effects generally reported that no or only mild harms occurred, and any serious adverse events were similar in intervention and control arms. However, adverse effects of periodontal treatments were not evaluated in most studies.

AUTHORS' CONCLUSIONS

Our 2022 update of this review has doubled the number of included studies and participants, which has led to a change in our conclusions about the primary outcome of glycaemic control and in our level of certainty in this conclusion. We now have moderate-certainty evidence that periodontal treatment using subgingival instrumentation improves glycaemic control in people with both periodontitis and diabetes by a clinically significant amount when compared to no treatment or usual care. Further trials evaluating periodontal treatment versus no treatment/usual care are unlikely to change the overall conclusion reached in this review.

Interplay Among the Oral Microbiome, Oral Cavity Conditions, the Host Immune Response, Diabetes Mellitus, and Its Associated-Risk Factors-An Overview

This comprehensive review of the literature aimed to investigate the interplay between the oral microbiome, oral cavity conditions, and host immune response in Diabetes mellitus (DM). Moreover, this review also aimed to investigate how DM related risk factors, such as advanced age, hyperglycemia, hyperlipidemia, obesity, hypertension and polycystic ovary syndrome (PCOS), act in promoting or modifying specific mechanisms that could potentially perpetuate both altered systemic and oral conditions. We found that poorly controlled glycemic index may exert a negative effect on the immune system of affected individuals, leading to a deficient immune response or to an exacerbation of the inflammatory response exacerbating DM-related complications. Hyperglycemia induces alterations in the oral microbiome since poor glycemic control is associated with increased levels and frequencies of periodontal pathogens in the subgingival biofilm of individuals with DM. A bidirectional relationship between periodontal diseases and DM has been suggested: DM patients may have an exaggerated inflammatory response, poor repair and bone resorption that aggravates periodontal disease whereas the increased levels of systemic pro-inflammatory mediators found in individuals affected with periodontal disease exacerbates insulin resistance. SARS-CoV-2 infection may represent an aggravating factor for individuals with DM. Individuals with DM tend to have low salivary flow and a high prevalence of xerostomia, but the association between prevalence/experience of dental caries and DM is still unclear. DM has also been associated to the development of lesions in the oral mucosa, especially potentially malignant ones and those associated with fungal infections. Obesity plays an important role in the induction and progression of DM. Co-affected obese and DM individuals tend to present worse oral health conditions. A decrease in HDL and, an increase in triglycerides bloodstream levels seem to be associated with an increase on the load of periodontopathogens on oral cavity. Moreover, DM may increase the likelihood of halitosis. Prevalence of impaired taste perception and impaired smell recognition tend to be greater in DM patients. An important interplay among oral cavity microbiome, DM, obesity and hypertension has been proposed as the reduction of nitrate into nitrite, in addition to contribute to lowering of blood pressure, reduces oxidative stress and increases insulin secretion, being these effects desirable for the control of obesity and DM. Women with PCOS tend to present a distinct oral microbial composition and an elevated systemic response to selective members of this microbial community, but the association between oral microbiome, PCOS are DM is still unknown. The results of the studies presented in this review suggest the interplay among the oral microbiome, oral cavity conditions, host immune response and DM and some of the DM associated risk factors exist. DM individuals need to be encouraged and motivated for an adequate oral health care. In addition, these results show the importance of adopting multidisciplinary management of DM and of strengthening physicians-dentists relationship focusing on both systemic and on oral cavity conditions of DM patients.

Novel Insight into the Mechanisms of the Bidirectional Relationship between Diabetes and Periodontitis

Periodontitis and diabetes are two major global health problems despite their prevalence being significantly underreported and underestimated. Both epidemiological and intervention studies show a bidirectional relationship between periodontitis and diabetes. The hypothesis of a potential causal link between the two diseases is corroborated by recent studies in experimental animals that identified mechanisms whereby periodontitis and diabetes can adversely affect each other. Herein, we will review clinical data on the existence of a two-way relationship between periodontitis and diabetes and discuss possible mechanistic interactions in both directions, focusing in particular on new data highlighting the importance of the host response. Moreover, we will address the hypothesis that trained immunity may represent the unifying mechanism explaining the intertwined association between diabetes and periodontitis. Achieving a better mechanistic insight on clustering of infectious, inflammatory, and metabolic diseases may provide new therapeutic options to reduce the risk of diabetes and diabetes-associated comorbidities.

Global burden of periodontal disease and its relation with socioeconomic development during 1990-2019

To analyze the global burden of periodontal disease and its relation with socioeconomic development. Data of global disability-adjusted life year (DALY) due to periodontal disease and human development index (HDI) from 1990 to 2019 were obtained from Global Health Data Exchange (GHDx) and human development reports. The trend of the global burden of periodontal disease from 1990 to 2019 was described. The correlation between age-standardized DALY rates and HDI were examined in 2019, and between-country periodontal disease burden inequality from 1990 to 2019 was measured using health-related Gini coefficients and concentration indexes. From 1990 to 2019, the global DALY rate due to periodontal disease increased from 78.63 to 85.48, and the epidemiological burden did not increase significantly. Statistical differences were found across different HDI categories for age-standardized DALY rates of periodontal disease ( 44.315, <0.01) in 2019. Linear regression analysis also revealed a negative correlation between age-standardized DALY rate of periodontal disease and HDI ( = -0.417, <0.01) . Gini coefficients decreased from 0.361 to 0.281 and concentration indexes fell from 0.0339 to -0.0538 between 1990 and 2019. The global burden of periodontal disease did not increase between 1990 and 2019, though the socioeconomic-associated inequality still existed. The burden of periodontal disease was more concentrated in less developed countries, and the socioeconomic-associated inequality has increased since 2000.

Clinical Outcomes and Oral Health-Related Quality of Life after Periodontal Treatment with Community Health Worker Strategy in Patients with Type 2 Diabetes: A Randomized Controlled Study

Interventions engaging community health workers (CHW) for diabetes management aim to improve diabetes care and self-management behaviors among patients. We evaluated the effects of nonsurgical periodontal treatment (NSPT) with the CHW strategy on oral self-care behaviors, periodontal status and oral health-related quality of life (OHQoL) in patients with type 2 diabetes mellitus (T2DM). The participants were randomly assigned to experimental (EG; n = 35) and control (CG; n = 33) groups. All participants received NSPT, whereas the patients in the EG also received one-on-one 30 min lessons from a CHW over 4 weeks. The EG exhibited greater improvement in the probing pocket depth (β = −0.2, effect size [ES] = 0.61) and clinical attachment level (β = −0.2, ES = 0.59) at 1-month follow-up than the CG did. The ES increased over the 1-, 3- and 6-month follow-ups, indicating an increase in OHQoL (ES = 0.19, 0.60, and 0.62, respectively) in the EG. The patients in the EG were more likely to change their oral self-care behaviors than patients in the CG were. The NSPT with CHW strategy had a positive effect on 1-month periodontal treatment outcomes, long-term OHQoL and oral self-care behaviors in patients with T2DM.

Diabetes and Oral Health: Summary of Current Scientific Evidence for Why Transdisciplinary Collaboration Is Needed

This Perspective provides a brief summary of the scientific evidence for the often two-way links between hyperglycemia, including manifest diabetes mellitus (DM), and oral health. It delivers in a nutshell examples of current scientific evidence for the following oral manifestations of hyperglycemia, along with any available evidence for effect in the opposite direction: periodontal diseases, caries/periapical periodontitis, tooth loss, peri-implantitis, dry mouth (xerostomia/hyposalivation), dysbiosis in the oral microbiome, candidiasis, taste disturbances, burning mouth syndrome, cancer, traumatic ulcers, infections of oral wounds, delayed wound healing, melanin pigmentation, fissured tongue, benign migratory glossitis (geographic tongue), temporomandibular disorders, and osteonecrosis of the jaw. Evidence for effects on quality of life will also be reported. This condensed overview delivers the rationale and sets the stage for the urgent need for delivery of oral and general health care in patient-centered transdisciplinary collaboration for early detection and management of both hyperglycemia and oral diseases to improve quality of life.

Effects of multiple sessions of antimicrobial photodynamic therapy (aPDT) in the treatment of periodontitis in patients with uncompensated type 2 diabetes: A randomized controlled clinical study

BACKGROUND

The aim of this study was to compare, through clinical and microbiological analysis, the use of multiple applications of aPDT as an adjuvant therapy to non-surgical periodontal treatment of stage III and IV grade C periodontitis in type 2 diabetic (DM2) patients.

METHODS

Thirty-four patients with non-compensated DM2 and periodontitis were randomly divided into two groups: SRP Group (n = 17): scaling and root planing (SRP); and SRP+aPDT Group (n = 17): SRP followed by 3 consecutive aPDT applications, immediately, 48 and 96 h after in pockets with probing depth (PD) ≥5 mm. In SRP+aPDT, after 1 min of irrigation with methylene blue (10 mg/ml), the sites were irradiated with a 660 nm diode laser for 50 s (157 J/cm², 4.7 J, 100 mW). Porphyromonas gingivalis (P. gingivalis) and Prevotella intermedia (P. intermedia) were quantified by real-time qPCR. Periodontal clinical and microbiological data (baseline, 90 and 180 days) were statistically analyzed (α = 5%).

RESULTS

There was a significant reduction in PD and bleeding on probing at 90 and 180 days post-treatment in both groups (p<0.05). The SRP+aPDT group presented a significant reduction in the number of residual pockets at 90 and 180 days (p<0.05). The SRP+aPDT group presented reduced PD means in deep pockets 180 days post-treatment (p<0.05). No differences were observed in P. gingivalis and P. intermedia levels (p>0.05).

CONCLUSION

The results of present study indicate that the use of multiples aPDT sessions as adjuvant therapy in the periodontal treatment of uncompensated diabetic patients with periodontitis promotes additional clinical benefits.

Characterization of salivary microbiota in elderly patients with type 2 diabetes mellitus: a matched case-control study

OBJECTIVE

The importance of oral health in type 2 diabetes mellitus (T2DM) is widely recognized; however, oral microbiota characteristics associated with T2DM in the elderly population are not well-understood. This study was conducted to evaluate the characteristics of the salivary microbiota in elderly Japanese patients with T2DM.

METHODS

Saliva samples were collected from 42 elderly Japanese patients with T2DM and 42 age- and sex-matched subjects without T2DM (control). 16S ribosomal RNA metagenomic analysis and comparative analysis of both groups were performed. Random forest classification by machine learning was performed to discriminate between the salivary microbiota in the two groups.

RESULTS

There were significant differences in the overall salivary microbiota structure between the T2DM and control groups (beta diversity; unweighted UniFrac distances, p = 0.001; weighted UniFrac distances, p = 0.001). The phylum Firmicutes was abundant in patients with T2DM, whereas the phylum Bacteroidetes was abundant in controls. The T2DM prediction model by random forest based on salivary microbiota data was verified with a high predictive potential in five cross-validation tests (area under the curve (AUC) = 0.938 (95% CI, 0.824-1.000)).

CONCLUSION

Characterization revealed that the salivary microbiota profile of the elderly patients with T2DM is significantly distinct from that of the controls.

CLINICAL RELEVANCE

These data indicate the necessity of oral health management based on the characteristics of the salivary microbiota in elderly patients with T2DM. Our findings will contribute to future research on the development of new diagnostic and therapeutic methods for this purpose.