Efficacy of 1% Metformin Gel in Patients With Moderate and Severe Chronic Periodontitis: A Randomized Controlled Clinical Trial

A sono-responsive antibacterial nanosystem co-loaded with metformin and bone morphogenetic protein-2 for mitigation of inflammation and bone loss in experimental peri-implantitis

Background

Dental implants have become an increasingly popular option for replacing missing teeth, and the prevalence of peri-implantitis has also increased, which is expected to become a public health problem worldwide and cause high economic and health burdens. This scenario highlights the need for new therapeutic options to treat peri-implantitis.

Methods

In this study, we proposed a novel sono-responsive antibacterial nanosystem co-loaded with metformin (Met) and bone morphogenetic protein-2 (BMP-2) to promote efficacy in treating peri-implantitis. We introduced the zeolitic imidazolate framework-8 (ZIF-8) as a carrier for hematoporphyrin monomethyl ether (HMME) to enhance the antibacterial effect of sonodynamic antibacterial therapy and tested its reactive oxygen species (ROS) production efficiency and bactericidal effect in vitro. Afterward, HMME-loaded ZIF-8, BMP-2-loaded polylactic acid-glycolic acid (PLGA), and Met were incorporated into gelatin methacryloyl (GelMA) hydrogels to form HMME@ZIF-8/Met/BMP-2@PLGA/GelMA composite hydrogels, and the biocompatibility of which was determined in vitro and in vivo. A bacterial-induced peri-implantitis model in the maxilla of rats was established to detect the effects of the composite hydrogels with adjunctive use of ultrasound on regulating inflammation and promoting bone tissue repair in vivo.

Results

The results indicated that HMME@ZIF-8 with ultrasound stimulation demonstrated more better ROS production efficiency and antimicrobial efficacy. The composite hydrogels had good biocompatibility. Ultrasound-assisted application of the composite hydrogels reduced the release of the inflammatory factors IL-6 and TNF-α and reduced bone loss around the implant in rats with bacterial-induced peri-implantitis.

Conclusion

Our observations suggest that HMME@ZIF-8 may be a new good sonosensitizer material for sonodynamic antibacterial therapy. The use of HMME@ZIF-8/Met/BMP-2@PLGA/GelMA composite hydrogels in combination with ultrasound can provide a novel option for treating peri-implantitis in the future.

From Basic Science to Clinical Practice: A Review of Current Periodontal/Mucogingival Regenerative Biomaterials

Periodontitis is a dysbiosis-driven inflammatory disease affecting the tooth-supporting tissues, characterized by their progressive resorption, which can ultimately lead to tooth loss. A step-wise therapeutic approach is employed for periodontitis. After an initial behavioral and non-surgical phase, intra-bony or furcation defects may be amenable to regenerative procedures. This review discusses the regenerative technologies employed for periodontal regeneration, highlighting the current limitations and future research areas. The search, performed on the MEDLINE database, has identified the available biomaterials, including biologicals (autologous platelet concentrates, hydrogels), bone grafts (pure or putty), and membranes. Biologicals and bone grafts have been critically analyzed in terms of composition, mechanism of action, and clinical applications. Although a certain degree of periodontal regeneration is predictable in intra-bony and class II furcation defects, complete defect closure is hardly achieved. Moreover, treating class III furcation defects remains challenging. The key properties required for functional regeneration are discussed, and none of the commercially available biomaterials possess all the ideal characteristics. Therefore, research is needed to promote the advancement of more effective and targeted regenerative therapies for periodontitis. Lastly, improving the design and reporting of clinical studies is suggested by strictly adhering to the Consolidated Standards of Reporting Trials (CONSORT) 2010 statement.

Metformin alleviates junctional epithelium senescence via the AMPK/SIRT1/autophagy pathway in periodontitis induced by hyperglycemia

The junctional epithelium (JE) serves a crucial protective role in the periodontium. High glucose-related aging results in accelerated barrier dysfunction of the gingival epithelium, which may be associated with diabetic periodontitis. Metformin, an oral hypoglycemic therapeutic, has been proposed as a anti-aging agent. This study aimed to clarify the effect of metformin on diabetic periodontitis and explore its mechanism in ameliorating senescence of JE during hyperglycemia. The db/db mice was used as a diabetic model mice and alterations in the periodontium were observed by hematoxylin-eosin staining and immunohistochemistry. An ameloblast-like cell line (ALC) was cultured with high glucose to induce senescence. Cellular senescence and oxidative stress were evaluated by SA-β-gal staining and Intracellular reactive oxygen species (ROS) levels. Senescence biomarkers, P21 and P53, and autophagy markers, LC3-II/LC3-I, were measured by western blotting and quantitative real-time PCR. To construct a stable SIRT1 (Sirtuin 1) overexpression cell line, we transfected ALCs with lentiviral vectors overexpressing the mouse SIRT1 gene. Cellular senescence was increased in the JE of db/db mice and the periodontium was destroyed, which could be alleviated by metformin. Moreover, oxidative stress and cellular senescence in a high glucose environment were reduced by metformin in in-vitro assays. The autophagy inhibitor 3-MA and SIRT1 inhibitor EX-527 could dampen the effects of metformin. Overexpression of SIRT1 resulted in increased autophagy and decreased oxidative stress and cellular senescence. Meanwhile, AMPK (AMP-activated protein kinase) inhibition reversed the anti-senescence effects of metformin. Overall, these results suggest that metformin alleviates periodontal damage in db/db mice and cellular senescence in ALCs under high glucose conditions via the AMPK/SIRT1/autophagy pathway.

Applications of Metformin in Dentistry-A review

Metformin is a versatile drug with numerous medical uses. It is known primarily as an anti-hyperglycemic drug that has become the main oral blood-glucose-lowering medication for managing type 2 diabetes mellitus globally. Its use has been reported in a variety of oral conditions and dentistry in general. Recent clinical trials have indicated the effectiveness of adjunct topical application of metformin in improving the periodontal parameters of patients with diabetes and periodontitis. Additionally, studies have suggested that metformin stimulates odontogenic differentiation and mineral synthesis of stem cells in the tooth pulp. Metformin also stimulates osteoblast proliferation, decreases osteoclast activity and exerts regenerative effects on periodontal bone, thus making it a viable candidate for periodontal regeneration. Metformin monotherapy significantly enhances osseointegration of endosseous implants and has been reported to have anti-cancer effects on oral squamous cell carcinoma by impeding tumor progression. Animal studies have indicated that metformin improves orthodontic tooth movement and resists orthodontic appliance corrosion. This narrative review aims to provide a current summary of research highlighting the prospective uses of metformin in dentistry.

Clinical efficacy of 1% metformin gel around conventionally placed dental implants: A 9-month follow-up study

Aim

The study aimed to compare the clinical and radiographic outcomes of bone volume, density, and crestal bone levels in conventionally placed dental implants with and without local application of 1% metformin (MF) gel using cone-beam computed tomography (CBCT) at 9 months.

Materials and Methods

Twenty implants were placed in 18 individuals, randomly divided into 2 groups where Group A received a local application of 1% MF gel along with implant placement. In contrast, Group B received implant placement alone. After thorough clinical examination and preoperative CBCTs, implants were placed under aseptic conditions. Patients were recalled at 3 and 9 months after surgery. Implants were functionally loaded by the end of 3rd month. Soft-tissue parameters such as modified plaque index and modified sulcular bleeding index were recorded along with CBCT evaluation to assess the crestal bone loss, bone density measurement, and bone volume, postoperatively. Fisher's extract test, independent and paired t-test, and Bonferroni analysis were used to determine statistical significance with P ≤ 0.05.

Results

There was no discernible difference between the groups regarding soft-tissue parameters, bone density, and crestal bone levels. However, comparing bone volume between the test and control groups at 9 months was statistically significant. The test group with 1% MF gel showed increased bone volume around the implant.

Conclusion

The data obtained were strong enough to suggest that 1% MF gel administered locally can increase peri-implant bone volume, possibly due to its additional property favoring osteoblastic stimulation and proliferation.

Gels as adjuvant to non-surgical periodontal therapy: A systematic review and meta-analysis

Objective

This systematic review and meta-analysis evaluated the effect of the use of available drugs loaded gels used as adjunct to non-surgical periodontal therapy.

Methods

Systematic research on PubMed/MEDLINE, Cochrane Central register of Controlled Trials, and Embase databases up to December 2021 was performed. Randomized clinical trials (RCT) which compared the outcomes of scaling and root planing (SRP) + local adjuvant administration (gel) versus SRP + placebo or SRP alone in Humans were included. The primary outcome measures were PPD and CAL changes at 3 months.

Results

After articles screening, 77 articles were included and assessed for quality. Then, a meta-analysis was conducted in studies with at least 3 months of follow-up. Clinical improvements were found to be significant for tetracyclines (-0.51 [-0.71;-0.31] p < 0.001), macrolides (-0.71 [-1.04;-0.38] p < 0.001), statins (-0.84 [-0.98;-0.70] p < 0.001), metformin (-1.47 [-1.66;-1.29] p < 0.001) and hyaluronan (-1.61 [-2.28;-0.94] p < 0.001) loaded gels, but non-significant for chlorhexidine (-0.48 [-1.10; 0.14] p = 0.13), metronidazole (-0.50 [-1.20; 0.20] p = 0.16) and bisphosphonates (-0.42 [-1.39; 0.54] p = 0.539) gels.

Conclusion

Adjunctive use of drugs loaded gels to non-surgical periodondal treatment could improve PPD reduction at 3 months. However, huge disparities remain when comparing the outcomes of the differents drugs used. Future comparative studies should be considered to determine precisely short and long term benefits of such treatments.

Adjunctive use of locally delivered host-modulators in intra-bony defects as part of step 2 periodontal therapy: systematic review, meta-analysis and trial sequential analysis

BACKGROUND

This systematic review and meta-analysis aimed at investigate the role of locally delivered host-modulators in combination with step 2 of periodontal therapy in reducing probing pocket depth, improving clinical attachment level and reducing bone defect depth in intra-bony defects.

HIGHLIGHT

RCT with at least 6 months follow-up were included in this study. Risk of bias assessment was performed with Cochrane collaboration tool and Grade GRADEpro. In addition, meta-analysis and trial sequential analysis were used to aggregate the available evidence. 22 studies met the inclusion criteria and were included in this systematic review. At 6 months locally delivered host-modulators significantly improved PD and CAL and bone defect depth.

CONCLUSION

Considering the emerging role of host-inflammatory response in the treatment of periodontitis, several studies are exploring the role of locally delivered host modulators as an adjunct to step 2 of periodontal therapy.

Efficacy of platelet rich fibrin with and without metformin in the treatment of periodontal osseous defects: a systematic review and meta-analysis

OBJECTIVE

The systematic review and meta-analysis aimed to evaluate the efficacy of Metformin (MF) with Platelet Rich Fibrin (PRF) over PRF alone in the treatment of periodontal osseous defects.

MATERIALS AND METHODS

An extensive electronic search for articles published up to September 2021 was conducted on 'Embase', 'PubMed' and other library databases accompanied with manual searching. Randomized controlled trials (RCTs), comparing MF plus PRF Vs PRF alone in periodontal osseous defects were identified in which periodontal pocket depth (PPD), Clinical attachment level (CAL) and Intrabony defect depth (IBD Depth) were the outcome measures.

RESULTS

Four studies compared MF plus PRF vs .PRF alone in periodontal osseous defects. Meta-analysis was carried out for PPD reduction, CAL gain and IBD Depth changes. A standardized mean difference (SMD) of 1.86 for PPD reduction, 1.95 for CAL gain and 1.31 for IBD Depth reduction in all the studies was observed and the findings were statistically significant favouring test group.

CONCLUSION

The systematic review indicates supplemental benefits of combination therapy of MF + PRF over monotherapy in resolving periodontal osseous defects. In our quest to achieve maximum regeneration in periodontal osseous defects, combination therapies such as MF + PRF have reported to be better treatment choices over other modalities.

Nanocarrier-Assisted Delivery of Metformin Boosts Remodeling of Diabetic Periodontal Tissue via Cellular Exocytosis-Mediated Regulation of Endoplasmic Reticulum Homeostasis

Endoplasmic reticulum (ER) dysfunction is a potential contributor to the impaired repair capacity of periodontal tissue in diabetes mellitus (DM) patients. Restoring ER homeostasis is thus critical for successful regenerative therapy of diabetic periodontal tissue. Recent studies have shown that metformin can modulate DM-induced ER dysfunction, yet its mechanism remains unclear. Herein, we show that high glucose elevates the intracellular miR-129-3p level due to exocytosis-mediated release failure and subsequently perturbs ER calcium homeostasis via downregulating transmembrane and coiled-coil domain 1 (TMCO1), an ER Ca²⁺ leak channel, in periodontal ligament stem cells (PDLSCs). This results in the degradation of RUNX2 via the ubiquitination-dependent pathway, in turn leading to impaired PDLSCs osteogenesis. Interestingly, metformin could upregulate P2X7R-mediated exosome release and decrease intracellular miR-129-3p accumulation, which restores ER homeostasis and thereby rescues the impaired PDLSCs. To further demonstrate the in vivo effect of metformin, a nanocarrier for sustained local delivery of metformin (Met@HALL) in periodontal tissue is developed. Our results demonstrate that compared to controls, Met@HALL with enhanced cytocompatibility and pro-osteogenic activity could boost the remodeling of diabetic periodontal tissue in rats. Collectively, our findings unravel a mechanism of metformin in restoring cellular ER homeostasis, enabling the development of a nanocarrier-mediated ER targeting strategy for remodeling diabetic periodontal tissue.

Metformin protects 5-Fu-induced chemotherapy oral mucositis by reducing endoplasmic reticulum stress in mice

Metformin (Met) is a first-line and essential treatment for type 2 diabetes, with anti-inflammatory effects. It has been reported Met could inhibit NF-κB activity and down-regulate the release of inflammatory factors. However, whether Met has a protective effect on chemotherapy-induced oral mucositis(CIOM) is unknown. The purpose of this study was to evaluate the protective effect of Metformin(Met) on chemotherapy-induced oral mucositis(CIOM) and further explore its possible mechanism. 5-Fu was used in the C57BL/6 mice to establish the model of CIOM. Our results showed Met could significantly improve 5-Fu-induced mucosal damage, apoptosis, ROS and releasing of inflammatory factors in the tongue tissue. In addition, Met could inhibit 5-Fu-induced high expression of endoplasmic reticulum stress(ERS)-related proteins GRP78 and CHOP. Further studies showed that the protective effect of ERS inhibitor 4-PBA on CIOM was similar to Met. Moreover, Met inhibited the phosphorylation of NF-κB in tongue tissue, independent of AMPK phosphorylation. The protective effect of PDTC, an inhibitor of NF-κB, on tongue tissue was similar to that of Met. This study confirmed the protective effect of Met on 5-Fu-induced CIOM, which was achieved by inhibiting ERS and reducing the activity of NF-κB.

Diabetes Medication Metformin Inhibits Osteoclast Formation and Activity in In Vitro Models for Periodontitis

Diabetes and periodontitis are comorbidities and may share common pathways. Several reports indicate that diabetes medication metformin may be beneficial for the periodontal status of periodontitis patients. Further research using appropriate cell systems of the periodontium, the tissue that surrounds teeth may reveal the possible mechanism. Periodontal ligament fibroblasts anchor teeth in bone and play a role in the onset of both alveolar bone formation and degradation, the latter by inducing osteoclast formation from adherent precursor cells. Therefore, a cell model including this type of cells is ideal to study the influence of metformin on both processes. We hypothesize that metformin will enhance bone formation, as described for osteoblasts, whereas the effects of metformin on osteoclast formation is yet undetermined. Periodontal ligament fibroblasts were cultured in the presence of osteogenic medium and 0.2 or 1 mM metformin. The influence of metformin on osteoclast formation was first studied in PDLF cultures supplemented with peripheral blood leukocytes, containing osteoclast precursors. Finally, the effect of metformin on osteoclast precursors was studied in cultures of CD14⁺ monocytes that were stimulated with M-CSF and receptor activator of Nf-κB ligand (RANKL). No effects of metformin were observed on osteogenesis: not on alkaline phosphatase activity, Alizarin red deposition, nor on the expression of osteogenic markers RUNX-2, Collagen I and Osteonectin. Metformin inhibited osteoclast formation and accordingly downregulated the genes involved in osteoclastogenesis: RANKL, macrophage colony stimulating factor (M-CSF) and osteoclast fusion gene DC-STAMP. Osteoclast formation on both plastic and bone as well as bone resorption was inhibited by metformin in M-CSF and RANKL stimulated monocyte cultures, probably by reduction of RANK expression. The present study unraveling the positive effect of metformin in periodontitis patients at the cellular level, indicates that metformin inhibits osteoclast formation and activity, both when orchestrated by periodontal ligament fibroblasts and in cytokine driven osteoclast formation assays. The results indicate that metformin could have a systemic beneficiary effect on bone by inhibiting osteoclast formation and activity.

Therapeutic Potential of Liraglutide for Diabetes-Periodontitis Comorbidity: Killing Two Birds with One Stone

BACKGROUND

The relationship between diabetes and periodontitis is bidirectional, and there is now consensus that periodontitis and diabetes are comorbid. There is a quest for a drug that can be used to treat both conditions simultaneously. This study evaluated the anti-inflammatory and osteoprotective effects of liraglutide (LIRA) on periodontitis in diabetic rats.

METHODS

Male Wistar rats (n = 46) were randomly divided into four groups: control group (n = 8), LIRA group (n = 8), diabetes-associated periodontitis+0.9% saline group (diabetic periodontitis (DP)+NaCl group, n = 15), and diabetes-associated periodontitis+LIRA group (DP+LIRA group, n = 15). LIRA treatment lasted for 4 weeks (300 μg/kg/d) after establishment of a rat model of DP. The expression of IL-6, TNF-α, and IL-1β was detected by enzyme-linked immunosorbent assay. The morphological changes of periodontal tissues were observed by hematoxylin-eosin staining. The absorption of alveolar bone and its ultrastructural changes were observed by histomorphometry and microcomputed tomography. The expression of receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) in alveolar bone was detected by immunohistochemistry. The levels of Runx2 mRNA and ALP mRNA in the gingival epithelium were examined by quantitative real-time polymerase chain reaction.

RESULTS

LIRA decreased alveolar bone resorption, improved the microstructure of alveolar bone, and reduced periodontal inflammation and damage (P < 0.05). LIRA also reduced blood glucose level and inhibited the secretion of serum IL-6, TNF-α, and IL-1β (P < 0.05). In addition, after treatment with LIRA, the ratio of RANKL/OPG was reduced, and the expression levels of ALP mRNA and Runx2 mRNA were upregulated (P < 0.05).

CONCLUSIONS

LIRA not only controls blood glucose level but also reduces inflammation and bone loss and enhances osteogenic differentiation in diabetes-associated periodontitis. Those indicate that LIRA may be used as a potential medicine for the adjunctive therapy of diabetes-periodontitis comorbidity.

Efficacy of 1.5% Metformin Gel as an Adjuvant to Scaling, Root Planing, and Curettage for the Treatment of Infrabony Defects in Chronic Periodontitis Patients

Context

To compare and evaluate clinically and radiographically the efficacy of 1.5% metformin (MF) gel and placebo gel as an adjunct to scaling and root planing (SRP) and Curettage for the treatment of infrabony defects (IBDs) in chronic periodontitis patients.

Subjects and Methods

The study was conducted randomly on 15 patients of both the genders. Each patient contributed two sites (total 30 sites - Split mouth design) which was randomly assigned to one of the two treatments: (i) Site A (Control Site) in which SRP was done along with curettage and intrapocket application of Placebo Gel and (ii) Site B (Test Site) in which SRP was done along with curettage and intrapocket application of 1.5% MF Gel. The Periodontal status {which included plaque index (PI), sulcus bleeding index (SBI), probing pocket depth (PPD), clinical attachment level (CAL), IBD Depth} was assessed both clinically and radiographically at baseline, 3 months, and 6 months after treatment.

Results

It was found that there was statistically significant difference in the periodontal status (PI, SBI, PPD, CAL, IBD depth) of the two sites when compared from baseline to 6 months.

Conclusions

Local delivery of 1.5% MF improves the clinical outcomes of traditional treatment (SRP) and curettage and should be considered particularly as an adjunct to it.

Unusual Findings in Trials Evaluating Adjuncts to Scaling and Root Planing: Meta-analysis (Part 1)

BACKGROUND

A number of studies in patients with periodontitis have compared scaling and root planning (SRP) combined with an adjunctive treatment to SRP alone. Within that literature, an array of studies with overlapping investigators has consistently yielded substantially greater effects of adjunctive treatments than had been previously noted. This report investigates discrepancies between that cluster of research and the most recent American Dental Association (ADA) systematic review.

METHODS

This review was preregistered at https://osf.io/4meyd/. A search using the Scopus platform identified 32 articles published from 2010 to 2017 by investigators affiliated with the Government Dental College and Research Institute (GDCRI) in Bangalore, India. The primary outcome used in this meta-analysis was the change in clinical attachment level (CAL) after 6 mo. Effect sizes were estimated using Comprehensive Meta-Analysis software after categorizing agents into groups based on pharmacologic similarity.

RESULTS

The search identified 32 studies encompassing 5 sets of adjunctive agents. Across the GDCRI studies, the CAL averaged 1.67 mm (95% confidence interval [CI]: 1.43-1.91 mm), substantially exceeding values reported in the ADA review (mean: 0.39 mm, 95% CI: 0.27-0.51 mm). For categories of studies in which comparable subgroup estimates were available, the evaluations yielded overlapping estimates of SRP alone, but CAL estimates were discrepant for both locally delivered antimicrobials (GDCRI studies: mean: 1.45 mm, 95% CI: 0.63-2.27 mm; ADA review: mean: 0.38 mm, 95% CI: 0.16 -0.60 mm) and systemic antibiotics (GDCRI studies: mean: 1.35 mm, 95% CI: 0.97-1.73 mm; ADA review: mean: 0.39 mm, 95% CI: 0.21-0.57 mm).

CONCLUSION

In the literature on adjunctive agents supplementing SRP, findings from investigators linked to GDCRI stand out as having significantly more favorable estimated effects. Meanwhile, some agents studied by GDCRI-linked investigators have not been investigated by other researchers. In the absence of a clear explanation for discrepant results, it is recommended that unusually favorable reported effects of adjunctive agents be viewed with caution.

KNOWLEDGE TRANSFER STATEMENT

The present meta-analysis observed an unusually large effect size of adjunctive agents to scaling and root planning in studies conducted by the same research group. These results were not consistent with trials on adjunctive agents and previous reports. As this research group has exclusively tested most of the agents, their results must be viewed with caution until other independent groups replicate the studies and reproduce the effect size.

Unusual Findings in Trials Evaluating Adjuncts to Scaling and Root Planing: Reporting Quality (Part 2)

INTRODUCTION

On the topic of adjuncts to scaling and root planing (SRP), numerous randomized clinical trials (RCTs) were published by a single group of authors and frequently reported unusually large effect sizes. A meta-analysis in part 1 of this project failed to explain the causes for these unusual findings. We assessed the reporting quality and trial registration discrepancies to examine the possibility of replicating the work of this research group as well as the overall rigor of the research methodology.

METHODS

This study was preregistered at the Open Science Framework (https://osf.io/4meyd/). The Scopus platform was utilized for the RCT search on SRP adjuncts in intrabony defects in patients with periodontitis as compared with SRP alone. The search analysis was limited from 2010 to 2017, and RCTs on SRP adjuncts published by a single research group were selected for screening and inclusion. RCT registration records were assessed for consistency.

RESULTS

Out of 92 studies that were retrieved from Scopus and PubMed, 32 were included for quality assessment per the CONSORT guidelines (Consolidated Standards of Reporting Trials). Results showed that all RCTs were characterized by a low reporting quality. The majority of CONSORT items scored <50%, including critical items (randomization, registration, and blinding). When registration records were compared with published RCTs, several discrepancies were found. The per-protocol follow-up duration was compared against the study's initiation and termination dates. Only 38% of the RCTs presented a follow-up period within the initiation and termination dates. The remaining RCTs showed inconsistent follow-up in comparison with the initiation and termination dates.

CONCLUSION

RCTs by this group were characterized by poor adherence to reporting quality guidelines. Crucial RCT elements, such as randomization, blinding, and primary outcomes, were not reported properly. RCT registration records revealed systematic inconsistencies when compared with RCT publication. Therefore, the unusually large effects reported by this group should be viewed with extreme caution.

KNOWLEDGE TRANSFER STATEMENT

The included randomized clinical trials were characterized by poor adherence to reporting quality guidelines, missing information about important trial items, and discrepancies between the reports and trial registrations. This quality assessment should guide clinical research and show clinicians that they should be cautious when applying evidence in their clinical practice.

Recent progress in materials development and biological properties of GTR membranes for periodontal regeneration

Chronic periodontal is a very common infection that instigates the destruction of oral tissue, and for its treatment, it is necessary to minimize the infection and the defects regeneration. Periodontium consists of four types of tissues: (a) cementum, (b) periodontal ligament, (c) gingiva, and 4) alveolar bone. In separated cavities, regenerative process also allows various cell proliferations. Guided tissue regeneration (GTR) is a potential procedure that favors periodontal regrowth; however, some limitations (such as ineffective hemostatic property, poor mechanical property, and improper biodegradation) are also associated with it. This review mainly emphasizes on the following areas: (a) a summarized overview of the periodontium and its immunological situations, (b) recently utilized treatments for regeneration of distinctive periodontal tissues; (c) an overview of GTR membranes available commercially, and the latest developments on the characterization and processing of GTR membrane material; and 4) the function of the different non-polymeric/polymeric materials, which are acting as drug carriers, antibacterial agents, nanoparticles, and periodontal barrier membranes to prevent periodontal inflammation and to improve the strength of the GTR membrane.

Clinico-radiographic comparative evaluation of 1% metformin gel plus platelet-rich fibrin over platelet-rich fibrin alone in treatment of Grade II furcation defects: A randomized controlled double-blind clinical trial

BACKGROUND

The present study was aimed to evaluate and compare the effects of 1% MF plus PRF over PRF alone in treatment of Grade II furcation defects, clinically and radiographically by using cone-beam computed tomography.

METHODS

This split-mouth clinical trial randomly allotted 21 patients with 42 bilateral Grade II furcation defects into two groups. Group I was treated with PRF alone while Group II with 1% MF gel and PRF. The primary outcome parameters were clinical attachment level (CAL) and horizontal probing depth (HPD) while the secondary outcome parameters were probing depth (PD) and defect volume (DV). The clinical parameters were evaluated at 3, 6, and 12 months and the radiographic parameters at 12 months.

RESULTS

Both the study groups yielded improvements in assessed parameters; however, significantly greater mean reduction of PD, HPD, and CAL gain was observed in Group II (3.90 ± 0.78 mm, 2.94 ± 0.80 mm, and 3.42 ± 0.93 mm) in comparison with Group I (3.23 ± 0.90 mm, 1.96 ± 0.80 mm, and 2.67 ± 0.88 mm) at 12 months, respectively. A significant reduction of DV was exhibited radiographically in Group II (12.61 ± 4.01 mm³ ) as compared with Group I (9.14 ± 4.31 mm³ ) at the end of 12 months.

CONCLUSIONS

Better clinical and radiographic findings in terms of reduction in PD, HPD, CAL gain, and significant reduction in DV in Group II patients indicated that the combination therapy of 1% MF + PRF promotes regenerative ability within the periodontal tissues in Grade II furcation defects to a greater extent.

The adjunctive use of host modulators in non-surgical periodontal therapy. A systematic review of randomized, placebo-controlled clinical studies

BACKGROUND

Considering the role of the inflammatory host response in the pathogenesis of periodontitis, different host modulators have been proposed to enhance the outcomes of non-surgical periodontal therapy (NSPT), but their efficacy has not been fully clarified.

OBJECTIVES

This systematic review investigated the efficacy of host modulators combined with NSPT in reducing probing pocket depth (PPD) in periodontitis patients.

MATERIALS AND METHODS

Placebo-controlled RCTs with ≥6 months follow-up were searched. Meta-analysis was conducted when ≥5 studies using the same host modulator were identified.

RESULTS

Fifty eight studies met the inclusion criteria. After 6 months, local administration of 1.2% statin gels as adjuncts to NSPT significantly improved PPD reduction (1.83 mm) in infrabony defects and systemic administration of sub-antimicrobial dose doxycycline (SDD) in addition to NSPT improved PPD reduction of deep pockets. Administration of probiotics conferred limited clinical benefits. Local bisphosphonate and metformin gels showed potential for clinical use in infrabony defects, which needs to be confirmed.

CONCLUSIONS

Local delivery of statins in infrabony defects and systemic SDD for deep pockets may confer additional clinical benefits to NSPT. Their long-term effectiveness and safety need to be confirmed in independent multi-centred studies. Further studies are needed to confirm the benefit of other host modulators.

Recent advances in periodontal regeneration: A biomaterial perspective

Periodontal disease (PD) is one of the most common inflammatory oral diseases, affecting approximately 47% of adults aged 30 years or older in the United States. If not treated properly, PD leads to degradation of periodontal tissues, causing tooth movement, and eventually tooth loss. Conventional clinical therapy for PD aims at eliminating infectious sources, and reducing inflammation to arrest disease progression, which cannot achieve the regeneration of lost periodontal tissues. Over the past two decades, various regenerative periodontal therapies, such as guided tissue regeneration (GTR), enamel matrix derivative, bone grafts, growth factor delivery, and the combination of cells and growth factors with matrix-based scaffolds have been developed to target the restoration of lost tooth-supporting tissues, including periodontal ligament, alveolar bone, and cementum. This review discusses recent progresses of periodontal regeneration using tissue-engineering and regenerative medicine approaches. Specifically, we focus on the advances of biomaterials and controlled drug delivery for periodontal regeneration in recent years. Special attention is given to the development of advanced bio-inspired scaffolding biomaterials and temporospatial control of multi-drug delivery for the regeneration of cementum-periodontal ligament-alveolar bone complex. Challenges and future perspectives are presented to provide inspiration for the design and development of innovative biomaterials and delivery system for new regenerative periodontal therapy.

Novel metformin-containing resin promotes odontogenic differentiation and mineral synthesis of dental pulp stem cells

This represents the first report on the development of metformin-containing dental resins. The objectives were to use the resin as a carrier to deliver metformin locally to stimulate dental cells for dental tissue regeneration and to investigate the effects on odontogenic differentiation of dental pulp stem cells (DPSCs) and mineral synthesis. Metformin was incorporated into a resin at 20% by mass as a model system. DPSC proliferation attaching on resins was evaluated. Dentin sialophosphoprotein (DSPP), dentin matrix phosphoprotein 1 (DMP-1), alkaline phosphatase (ALP), and runt-related transcription factor 2 (Runx2) genes expressions were measured. ALP activity and alizarin red staining (ARS) of mineral synthesis by the DPSCs on resins were determined. DPSCs on metformin-containing resin proliferated well (mean ± SD; n = 6), and the number of cells increased by 4-fold from 1 to 14 days (p > 0.1). DSPP, ALP, and DMP-1 gene expressions of DPSCs on metformin resin were much higher than DPSCs on control resin without metformin (p < 0.05). ALP activity of metformin group was 70% higher than that without metformin at 14 days (p < 0.05). Mineral synthesis by DPSCs on metformin-containing resin at 21 days was 9-fold that without metformin (p < 0.05). A novel metformin-containing resin was developed, achieving substantial enhancement of odontoblastic differentiation of DPSCs and greater mineral synthesis. The metformin resin is promising for deep cavities and perforated cavities to stimulate DPSCs for tertiary dentin formation, for tooth root coatings with metformin release for periodontal regeneration, and for root canal fillings with apical lesions to stimulate bone regeneration.