Effect of an extraoral scavenging device on eliminating droplets and aerosols generated in ultrasonic supragingival scaling: A randomised clinical trial.

OBJECTIVES: Ultrasonic scaling is extensively applied as part of the initial therapy for periodontal diseases, which has been restricted since the outbreak of the COVID-19 pandemic due to droplets and aerosols generated by ultrasonic devices. An extraoral scavenging device (EOS) was designed for diminishing droplets and aerosols in dental clinics. The objective of this study is to evaluate the effect of EOS on eliminating droplets and aerosols during ultrasonic supragingival scaling. METHODS: This single-blinded, randomised controlled clinical trial enrolled 45 patients with generalised periodontitis (stage I or II, grade A or B) or plaque-induced gingivitis. The patients were randomly allocated and received ultrasonic supragingival scaling under three different intervention measures: only saliva ejector (SE), SE plus EOS and SE plus high-volume evacuation (HVE). The natural sedimentation method was applied to sample droplets and aerosols before or during supragingival scaling. After aerobic culturing, colony-forming units (CFUs) were counted and analysed. RESULTS: Compared with the level before treatment, more CFUs of samples throughout treatment could be obtained at the operator's chest and the patient's chest and the table surface when using SE alone (p < 0.05). Compared with the SE group, the SE + EOS group and the SE + HVE group obtained decreasing CFUs at the operator's chest and the patient's chest (p < 0.05), while no significant difference was determined between these two groups. CONCLUSIONS: The EOS effectively eliminated splatter contamination from ultrasonic supragingival scaling, which was an alternative precaution for nosocomial contamination in dental clinics.

Non-invasive assessment of periodontal inflammation by continuum-removal hemodynamic spectral indices.

BACKGROUND: Hyperspectral techniques have aroused great interest in non-invasively measuring periodontal tissue hemodynamics. However, current studies mainly focused on three typical inflammation stages (healthy, gingivitis and periodontitis) and practical approaches for using optical spectroscopy for early and precisely detection of periodontal inflammation at finer disease stages have not been well studied. METHODS: This study provided novel spectroscopic insights into periodontitis at different stages of disease, and developed six simple but physically meaning hemodynamic spectral indices (HSIs) including four spectral absorption depths of oxyhemoglobin ( D HbO 2 ), deoxyhemoglobin ( D Hb ), total hemoglobin ( t Hb ) and tissue water ( D water ), and two normalized difference indices of oxyhemoglobin( N D HbO 2 I ) and deoxyhemoglobin ( N D Hb I ) from continuum-removal spectra (400-1700 nm) of periodontal tissue collected from 47 systemically healthy subjects over different severities from healthy, gingivitis, slight, moderate to severe periodontitis for early and precision diagnostics of periodontitis. Typical statistical analyses were conducted to explore the effectiveness of the proposed HSIs. RESULTS: D Hb and t Hb exerted significant increasing trends as inflammation progressed, whereas D HbO 2 exhibited significant difference (P < 0.05) from the healthy sites only at moderate and severe periodontitis and D water presented unstable sensitives to disease severity. By contrast, N D HbO 2 I and N D Hb I showed more steadily downward trends as severity increased, and demonstrated the highest correlations with clinical gold standard parameters. Particularly, the proposed normalized HSIs ( N D HbO 2 I and N D Hb I ) yielded high correlations of - 0.49 and - 0.44 with probing depth, respectively, far outperforming results achieved by previous studies. The performances of the HSIs were also confirmed using the periodontal therapy group. CONCLUSIONS: These results indicated great potentials of combination optical spectroscopy and smart devices to non-invasively probe periodontitis at earlier stages using the simple and practical HSIs. Trial registration This study was retrospectively registered in the Chinese Clinical Trial Registry on October 24, 2021, and the clinical registration number is ChiCTR2100052306.

Epstein-Barr Virus Promotes Inflammatory Cytokine Production in Human Gingival Fibroblasts.

BACKGROUND: Periodontitis is one of the most common chronic oral inflammatory diseases. Over the past decade, herpes viruses, particularly Epstein-Barr virus (EBV), have been considered promising pathogenic candidates for periodontitis. However, the specific mechanism by which EBV contributes to the development of periodontitis is still unknown. This study aimed to explore the mechanism of EBV underlying the inflammatory response in human gingival fibroblasts (HGFs). MATERIALS AND METHODS: HGFs were stimulated with different concentrations of EBV (104, 105, 106, 107, and 108 DNA copies/mL) for 0, 8, 24, or 48 hours. The mRNA levels of interleukin (IL)-1ß, tumour necrosis factor-α (TNF-α), IL-8, monocyte chemoattractant protein-1 (MCP-1), and Toll-like receptor 9 (TLR9) were measured using quantitative real-time polymerase chain reaction (PCR). Enzyme-linked immunosorbent assays (ELISAs) were performed for determining the mRNA and protein levels of IL-1ß, TNF-α, IL-8, and MCP-1. Real-time PCR and ELISA were performed to determine the protein levels of IL-1ß, TNF-α, IL-8, and MCP-1. Activation of the TLR9/myeloid differentiation factor 88 (MyD88)/nuclear factor kappa B (NF-κB) pathway was evaluated using western blotting. RESULTS: The expressions of IL-1ß, TNF-α, IL-8, and MCP-1 were significantly upregulated in HGFs under EBV stimulation in a concentration- and time-dependent manner. EBV promoted TLR9 and MyD88 expression and induced NF-κB transcription. On the contrary, the upregulation of these factors and the activation of NF-κB pathway were drastically inhibited by TLR9 antagonists. CONCLUSIONS: Our findings demonstrate that EBV promotes the production of inflammatory cytokines IL-1ß and TNF-α and chemokines IL-8 and MCP-1 in HGFs through the TLR9/MyD88/NF-κB pathway.

Efficacy of concentrated growth factor (CGF) in the surgical treatment of oral diseases: a systematic review and meta-analysis.

BACKGROUND: Concentrated growth factor (CGF), a new autologous platelet concentrate, has been widely investigated to the adjunctive treatment of oral diseases. This study aims to evaluate the efficacy of CGF in the surgical treatment of oral diseases. METHODS: MEDLINE, Web of Science, Scopus, Cochrane, and EMBASE databases were searched up to July 2023. Only randomized clinical trials were included. The methodologic quality was evaluated by the Cochrane Risk of Bias Tool. RevMan 5.4 software was used for data analysis. RESULTS: In the treatment of periodontal intrabony defects, bone graft combined with CGF was significantly superior to bone graft (P < 0.01), with mean intrabony defect depth reduction of 1.41 mm and mean clinical attachment level gain of 0.55 mm. In the regenerative surgery of furcation defects, the effect of CGF group was significantly better than control group (P < 0.0001), with mean probing depth reduction of 0.99 mm, vertical bone gain of 0.25 mm, and horizontal bone gain of 0.34 mm. CGF combined with coronally advanced flap (CAF) was more effective than CAF alone (mean keratinized tissue width increase of 0.41 mm, mean gingival thickness increase of 0.26 mm, P < 0.00001), but less effective than connective tissue graft (CTG) combined with CAF (mean root coverage difference of -15.1%, mean gingival thickness difference of -0.5 mm, P < 0.0001). In the alveolar ridge preservation, additional use of CGF reduced horizontal bone resorption by 1.41 mm and buccal vertical bone resorption by 1.01 mm compared to control group (P < 0.0001). The VAS score of CGF group was significantly lower than that of the control group at the 1st and 7th day after oral surgery (P < 0.0001). CONCLUSIONS: CGF can exert a positive adjunctive effect for the regenerative surgery of periodontal intrabony defects, furcation defects, and alveolar ridge preservation procedure. CGF combined with CAF has a better therapeutic effect on gingival recession compared to CAF alone, although it is not as effective as CTG combined with CAF. CGF could promote postoperative healing and pain relief in oral surgery within a week. There is currently not enough evidence to support the clinical benefits of CGF in other oral surgeries.

Association of carotid intima-media thickness with periodontitis may depend on glycemic control.

BACKGROUND: There is evidence indicating that atherosclerosis is associated with periodontitis, especially in those with diabetes. The purpose of the present study was to determine whether glycemic control influences such association. METHODS: Cross-sectional data on 214 patients diagnosed with type 2 diabetes mellitus were obtained including results of basic laboratory tests, a periodontal examination, and carotid measurements. The association of periodontal parameters and carotid intima-media thickness (cIMT) or carotid plaque (CP) was evaluated in subgroups. RESULTS: Mean cIMT was significantly correlated with mean PLI, mean BI or number of PD ≥4 mm in the whole sample and the group with poor glycemic control. In the group with good glycemic control, however, only the number of PD ≥4 mm was associated with mean cIMT. A multiple logistic regression analysis also revealed that each 1 increase in mean PLI, mean BI or number of PD ≥4 mm was correlated with an increased cIMT in the whole sample. CONCLUSIONS: In addition to confirming the relationship between periodontitis and atherosclerosis, our study found a stronger association in groups with poor glycemic control compared to those with good glycemic control, suggesting that blood glucose modifies the association between periodontitis and arterial injury.

Regulatory B cells induced by interleukin-35 inhibit inflammation and alveolar bone resorption in ligature-induced periodontitis.

BACKGROUND: Regulatory B cells (Bregs) have been reported to suppress immune responses and alveolar bone loss in murine periodontitis models. These cells could be induced by interleukin (IL)-35 which is increased upon periodontal inflammation. Thus, this study aimed to explore the role of Bregs induced by IL-35 in periodontitis. METHODS: Experimental periodontitis was induced in mice by ligature. Two weeks after ligation, the test group was systemically treated with IL-35 for 1 week. Four weeks after ligation, all mice were euthanized, and alveolar bone loss was evaluated by microcomputed tomography. Cytokines associated with periodontitis were analyzed using reverse transcription-quantitative polymerase chain reaction and enzyme-linked immunosorbent assay. Bregs in spleens, cervical lymph nodes, and periodontal tissues were detected by flow cytometry and immunofluorescence staining. RESULTS: In the mouse model of periodontitis, IL-35 induced the expansion of CD1dhi CD5+ B10 cells with increased interleukin-10 (IL-10) and IL-35 production. IL-35 administration also attenuated alveolar bone loss and reduced the levels of proinflammatory cytokines in situ. CONCLUSIONS: Following ligature-induced periodontitis in mice, IL-35 inhibited periodontal inflammation and alveolar bone resorption at least partially through the induction of B10 cells and IL-35+ Bregs.

The role of PRX1-expressing cells in periodontal regeneration and wound healing.

The ideal outcome of wound healing is the complete restoration of the structure and function of the original tissue. Stem cells are one of the key factors in this process. Currently, the strategy of periodontal regeneration based on mesenchymal stem cells (MSCs) is generally used to expand stem cells in vitro and then transplant them in vivo. However, their clinical application is limited. In fact, the human body has the capacity to regenerate through stem cells residing in different tissues, even without external therapeutic intervention. Stem cell niches are present in many adult tissues, such as the periodontal ligament and gingiva, and stem cells might remain in a quiescent state in their niches until they are activated in response to a regenerative need. Activated stem cells can exit the niche and proliferate, self-renew, and differentiate to regenerate original structures. Thus, harnessing the regenerative potential of endogenous stem cells in situ has gained increasing attention as a simpler, safer, and more applicable alternative to stem cell transplantation. Nevertheless, there are several key problems to be solved in the application of periodontal mesenchymal stem cells. Thus, animal studies will be especially important to deepen our knowledge of the in vivo mechanisms of mesenchymal stem cells. Studies with conditional knockout mice, in which the expression of different proteins can be eliminated in a tissue-specific manner, are especially important. Post-natal cells expressing the paired-related homeobox protein 1 (PRX1 or PRRX1), a transcription factor expressed in the mesenchyme during craniofacial and limb development, have been shown to have characteristics of skeletal stem cells. Additionally, following wounding, dermal Prx1+ cells are found out of their dermal niches and contribute to subcutaneous tissue repair. Postnatal Prx1+ cells are uniquely injury-responsive. Meanwhile, current evidence shows that Prx1+ cells contribute to promote dentin formation, wound healing of alveolar bone and formation of mouse molar and periodontal ligament. Initial result of our research group also indicates Prx1-expressing cells in bone tissue around the punch wound area of gingiva increased gradually. Collectively, this review supports the future use of PRX1 cells to stimulate their potential to play an important role in endogenous regeneration during periodontal therapy.

Survival of nonsurgically splinted mandibular anterior teeth during supportive maintenance care in periodontitis patients.

Background/purpose: Splinting mobile teeth is a choice to improve the patient's oral comfort. The purpose of this study was to assess the survival and stability of mobile anterior mandibular teeth after splinting in patients with periodontitis undergoing supportive periodontal therapy (SPT). Materials and methods: Patients with splinted mobile anterior mandibular teeth were assessed retrospectively. Periodontal statuses were recorded at baseline and follow-up visits. Tooth and splint survival as well as splint repairs were recorded. Multilevel Cox regression analyses were performed to evaluate patient- and tooth-related factors that might have influenced the survival rates of splints. Results: Sixty-one patients, collectively having 161 splints, were followed for an average of 5.44 years. On average, probing depth (PD) of splinted teeth decreased from 4.31 mm to 2.93 mm and clinical attachment loss (CAL) decreased from 5.02 mm to 4.58 mm. Alveolar bone was stable in the follow-up period. None of the splinted teeth were extracted, The overall survival rate of the splints was 65.2%. Splints made of composite resin alone were associated with a higher risk of breakage when compared to splints composed of composite resin with mesh grid strips. Conclusion: Splinting showed long-term survival and splinting combined with periodontal supportive treatment is a feasible option to maintain mobile mandibular anterior teeth.

Weak direct current exerts synergistic effect with antibiotics and reduces the antibiotic resistance: An in vitro subgingival plaque biofilm model.

BACKGROUND AND OBJECTIVE: Weak direct current (DC) exerts killing effect and synergistic killing effect with antibiotics in some specific bacteria biofilms. However, the potential of weak DC alone or combined with periodontal antibiotics in controlling periodontal pathogens and plaque biofilms remains unclear. The objective of this study was to investigate whether weak DC could exert the anti-biofilm effect or enhance the killing effect of metronidazole (MTZ) and/or amoxicillin-clavulanate potassium (AMC) on subgingival plaque biofilms, by constructing an in vitro subgingival plaque biofilm model. METHODS: The pooled subgingival plaque and saliva of patients with periodontitis (n = 10) were collected and cultured anaerobically on hydroxyapatite disks in vitro for 48 h to construct the subgingival plaque biofilm model. Then such models were stimulated with 0 µA DC alone (20 min/12 h), 1000 µA DC alone (20 min/12 h), 16 µg/ml MTZ, 16 µg/ml AMC or their combination, respectively. Through viable bacteria counting, metabolic activity assay, quantitative real-time PCR absolute quantification and 16S rDNA sequencing analysis, the anti-biofilm effect of 1000 µA DC and enhanced killing effects of 1000 µA DC combined with antibiotics (MTZ, AMC or MTZ+AMC) were explored. RESULTS: The old subgingival plaque model (48 h) had no significant difference in total bacterial loads from subgingival plaque in situ, which achieved a similarity of 80%. The 1000 µA DC plus MTZ or AMC for 12 h showed a stronger synergistic killing effect than the same combination for 20 min. The metabolic activity was reduced to the lowest by DC plus MTZ+AMC, as 37.4% of that in the control group, while average synergistic killing effect reached 1.06 log units and average total bacterial loads decreased to 0.87 log units. Furthermore, the relative abundance of the genera Porphyromonas, Prevotella, Treponema_2, and Tannerella were decreased significantly. CONCLUSION: The presence of weak DC (1000 µA) improved the killing effect of antibiotics on subgingival plaque biofilms, which might provide a novel strategy to reduce their antibiotic resistance.

Oxidative stress in human gingival fibroblasts from periodontitis versus healthy counterparts.

OBJECTIVE: Elevated p53 promotes oxidative stress and production of pro-inflammatory cytokines in liposaccharide (LPS)-treated healthy human gingival fibroblasts (HGFs). This study compared oxidative stress, production of inflammatory cytokines, and p53 expression in HGFs from patients with chronic periodontitis (CP) and healthy subjects in vitro upon LPS from Porphyromonas gingivalis challenge. METHODS: Human gingival fibroblasts were isolated from 6 biopsies-3 from healthy donors and 3 from diseased area in CP (Grade B, Stage III). HGFs were cultured with or without 1 µg/ml 24 h LPS. Oxidative stress was assessed by analyzing the level of reactive oxygen species (ROS). Mitochondrial membrane potential and respiration were determined by immunofluorescence and respirometry, respectively. Tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1ß were determined by enzyme-linked immunosorbent assay. P53 expression was monitored by Western blot and immunofluorescence. RESULTS: Human gingival fibroblasts from CP exhibited increased levels of mitochondrial p53, enhanced ROS production, decreased mitochondrial membrane potential, increased mitochondrial oxygen consumption, and increased secretion of TNF-α, IL-6, and IL-1ß, as compared to HGFs from healthy donors. Moreover, LPS exacerbated these changes. CONCLUSION: Human gingival fibroblasts from CP exhibited stronger basal and LPS-inducible oxidative stress and inflammatory response as compared to HGFs from healthy subjects by increased p53 in mitochondria.

Effect of partial restorative treatment on stress distributions in non-carious cervical lesions: a three-dimensional finite element analysis.

BACKGROUND: Partial restoration combined with periodontal root coverage surgery can be applied to the treatment of non-carious cervical lesions (NCCLs) accompanied with gingival recessions in clinical practice. However, the feasibility of NCCL partial restorative treatment from a biomechanical perspective remains unclear. This study aimed to investigate the effect of partial restorations on stress distributions in the NCCLs of mandibular first premolars via three-dimensional finite element analysis. METHODS: Three-dimensional finite element models of buccal wedge-shaped NCCLs in various locations of a defected zenith (0 mm, 1 mm, and 2 mm) were constructed and divided into three groups (A, B, and C). Three partially restored NCCL models with different locations of the lower restoration border (1 mm, 1.5 mm, and 2 mm), and one completely restored NCCL model were further constructed for each group. The following restorative materials were used in all restoration models: composite resin (CR), glass-ionomer cement (GIC), and mineral trioxide aggregate (MTA). The first principal stress distributions under buccal oblique loads of 100 N were analyzed. Restoration bond failures were also evaluated based on stress distributions at dentin-restoration interfaces. RESULTS: When the partial restoration fully covered the defected zenith, the first principal stress around the zenith decreased and the maximum tensile stress was concentrated at the lower restoration border. When the partial restoration did not cover the defected zenith, the first principal stress distribution patterns were similar to those in unrestored models, with the maximum tensile stress remaining concentrated at the zenith. As the elastic modulus of the restorative material was altered, the stress distributions at the interface were not obviously changed. Restoration bond failures were not observed in CR, but occurred in GIC and MTA in most models. CONCLUSIONS: Partial restorations that fully covered defected zeniths improved the stress distributions in NCCLs, while the stress distributions were unchanged or worsened under other circumstances. CR was the optimal material for partial restorations compared to GIC and MTA.

Periodontitis induced by Porphyromonas gingivalis drives impaired glucose metabolism in mice.

Periodontitis has been demonstrated to be bidirectionally associated with diabetes and has been recognized as a complication of diabetes. As a periodontal pathogen, Porphyromonas gingivalis is a possible pathogen linking periodontal disease and systemic diseases. It has also been found to be involved in the occurrence and development of diabetes. In this study, 6-week-old male C57BL/6 mice were orally administered the P. gingivalis strain ATCC381 for 22 weeks. Histological analysis of the gingival tissue and quantified analysis of alveolar bone loss were performed to evaluate periodontal destruction. Body weight, fasting glucose, glucose tolerance test (GTT), and insulin tolerance test (ITT) were used to evaluate glucose metabolism disorder. We then analyzed the expression profiles of inflammatory cytokines and chemokines in gingival tissue, the liver, and adipose tissue, as well as in serum. The results showed that mice in the P. gingivalis-administered group developed apparent gingival inflammation and more alveolar bone loss compared to the control group. After 22 weeks of P. gingivalis infection, significant differences were observed at 30 and 60 min for the GTT and at 15 min for the ITT. P. gingivalis-administered mice showed an increase in the mRNA expression levels of the pro-inflammatory cytokines (TNF-α, IL-6, IL-17, and IL-23) and chemokines (CCL2, CCL8, and CXCL10) in the gingiva and serum. The expression levels of the glucose metabolism-related genes were also changed in the liver and adipose tissue. Our results indicate that oral administration of P. gingivalis can induce changes in the inflammatory cytokines and chemokines in the gingiva and blood, can lead to alveolar bone loss and to inflammatory changes in the liver and adipose tissues, and can promote glucose metabolism disorder in mice.

Treatment of multiple gingival recessions with concentrated growth factor membrane and coronally advanced tunnel technique via digital measurements: A randomized controlled clinical trial.

Background/purpose: Research into biomaterial alternatives to connective tissue grafts (CTG) is a research hotspot. The purpose of this clinical trial was to compare the effectiveness of root coverage through tunnel technique with concentrated growth factor (CGF) vs CTG in treating multiple gingival recessions using digital measurements. Materials and methods: Seventy Cairo Class I multiple gingival recessions (in 28 patients) were treated with either CGF or CTG combined with coronally advanced tunnel technique. Digital models were obtained at baseline, 2 weeks, 6 weeks, and 6 months post-op to compare the gain in gingival height, area, volume, and thickness. Tooth sensitivity, post-operative pain, and healing index were also recorded. Results: Complete root coverage at 6 months post-op were 47.06% in the CGF group and 77.78% in the CTG groups. Mean root coverages were 80.55% and 96.18%, respectively. No statistical difference was demonstrated between the two groups in terms of gingival area gain at 2 weeks post-op, but the CTG group had greater increases in gingival height, area, volume, and thickness in the period after 2 weeks post-op. Pain scores were statistically significantly lower in the CGF group. At 6 months post-op, sensitivity scores decreased more significantly in the CTG group. Conclusion: Digital measurements revealed post-operative gingival shrinkage was more pronounced in the CGF group than in the CTG group when combined with coronally advanced tunnel technique. Despite the ease-of-use and minimal post-operative discomfort, it is difficult to achieve similar root coverage outcomes to CTG when using CGF alone in treating multiple gingival recessions.

Mitochondrial DNA Efflux Maintained in Gingival Fibroblasts of Patients with Periodontitis through ROS/mPTP Pathway.

Mitochondria have their own mitochondrial DNA (mtDNA). Aberrant mtDNA is associated with inflammatory diseases. mtDNA is believed to induce inflammation via the abnormal mtDNA release. Periodontitis is an infectious, oral inflammatory disease. Human gingival fibroblasts (HGFs) from patients with chronic periodontitis (CP) have shown to generate higher reactive oxygen species (ROS) that cause oxidative stress and have decreased mtDNA copy number. Firstly, cell-free mtDNA was identified in plasma from CP mice through qRT-PCR. Next, we investigated whether mtDNA efflux was maintained in primary cultures of HGFs from CP patients and the possible underlying mechanisms using adenovirus-mediated transduction live cell imaging and qRT-PCR analysis. Here, we reported that mtDNA was increased in plasma from the CP mice. Additionally, we confirmed that CP HGFs had significant mtDNA efflux from mitochondria compared with healthy HGFs. Furthermore, lipopolysaccharide (LPS) from Porphyromonas gingivalis can also cause mtDNA release in healthy HGFs. Mechanistically, LPS upregulated ROS levels and mitochondrial permeability transition pore (mPTP) opening by inhibition of pyruvate dehydrogenase kinase (PDK)2 expression, resulting in mtDNA release. Importantly, mtDNA efflux was even persistent in HGFs after LPS was removed and cells were passaged to the next three generations, indicating that mtDNA abnormalities were retained in HGFs in vitro, similar to the primary hosts. Taken together, our results elucidate that mtDNA efflux was maintained in HGFs from periodontitis patients through abnormal ROS/mPTP activity. Therefore, our work indicates that persistent mtDNA efflux may be a possible diagnostic and therapeutic target for patients with periodontitis.

The effect of (-)-epigallocatechin gallate as an adjunct to non-surgical periodontal treatment: a randomized clinical trial.

BACKGROUND: EGCG is proven to be of good effect to relieve periodontal inflammation, but it has not been applied as a local delivery medicine in patients with periodontitis widely. The aim of this clinical trial was to evaluate the adjunctive effect of (-)-epigallocatechin gallate (EGCG) aqueous solution as a coolant during scaling and root planing in the management of chronic periodontitis. METHODS: A double-blind, randomized controlled study was performed on 15 patients with moderate to severe chronic periodontitis. The bilateral maxillary teeth were randomly divided into the test side and the control side on every individual. On the control side, the periodontal therapy was routinely performed. And on the test side, in the process of periodontal therapy, the distilled water in the ultrasonic scaler was replaced with a 5-mg/mL EGCG solution. The probing depth (PPD), clinical attachment level (CAL), bleeding index (BI), gingival index (GI), and plaque index (PI) were recorded at baseline and 6 and 12 weeks after the treatment. RESULTS: PPD, CAL, BI, GI, and PI generally improved after treatment in both groups. At the sixth week and the twelfth week of review, PPD, CAL, GI, and PI had no statistical difference (p >0.05) between the two groups. At the review of the twelfth week, BI on the test side decreased significantly (p <0.05). CONCLUSIONS: Using EGCG solution as the irrigant instead of water has an additional benefit on the bleeding index at the 12-week review. However, the rest clinical parameters had no additional benefit. TRIAL REGISTRATION: ClinicalTrials.gov ChiCTR2000029831 , date of registration: Feb 15, 2020.

MFN2 knockdown promotes osteogenic differentiation of iPSC-MSCs through aerobic glycolysis mediated by the Wnt/ß-catenin signaling pathway.

BACKGROUND: Mitofusin-2 (MFN2) is a kind of GTPase that participates in the regulation of mitochondrial fusion, which is related to a variety of physiological and pathological processes, including energy metabolism, cell differentiation, and embryonic development. However, it remains unclear whether MFN2 is involved in the metabolism and osteogenic differentiation of mesenchymal stem cells (MSCs). METHODS: MFN2 knockdown (MFN2-KD) and MFN2-overexpressing (MFN2-OE) induced pluripotent stem cell-derived mesenchymal stem cells (iPSC-MSCs) were constructed by lentivirus. The commercial kits were utilized to detect the glycolysis and oxidative phosphorylation (OXPHOS) rate. Flow cytometry, Western blot, quantitative real-time polymerase chain reaction (qRT-PCR), RNA-seq, immunofluorescence, and immunoprecipitation were employed for phenotype and molecular mechanism assessment. RESULTS: We demonstrated that MFN2 and Wnt/ß-catenin signaling pathway regulated glycolysis of iPSC-MSCs. The lack of MFN2 promoted the osteogenic differentiation of iPSC-MSCs, and aerobic glycolysis in the presence of sufficient oxygen, which increased glucose consumption and lactic acid production, as well as the glycolytic enzyme activity and gene expression. Inhibiting the Wnt/ß-catenin signaling pathway normalized the enhanced glycolytic rate and osteogenic differentiation of MFN2-KD iPSC-MSCs. MFN2-OE iPSC-MSCs displayed the opposite phenotype. CONCLUSIONS: Downregulating MFN2 promotes osteogenic differentiation of iPSC-MSCs through aerobic glycolysis mediated by the Wnt/ß-catenin signaling pathway. Our research reveals the new function of MFN2 in regulating the osteogenic differentiation and energy metabolism of MSCs, which will provide a new therapeutic target and theoretical basis for alveolar bone repair and periodontal regenerative treatment.

Effectiveness of modified periodontally accelerated osteogenic orthodontics in skeletal class II malocclusion treated by a camouflage approach.

Skeletal Class II malocclusion is a complex orofacial condition. Here, we translated the single clinical problem to a multidisciplinary approach that combined the periodontal surgery, biomaterial implantation, and orthodontics to treat this condition. This study aimed to explore the clinical effectiveness of modified periodontally accelerated osteogenic orthodontics (PAOO) in adult patients with skeletal Class II discrepancy via a camouflage orthodontic approach. This clinical trial has been registered in the Chinese Clinical Trial Registry (trial number: ChiCTR2100052638, trial URL: http://www.chictr.org.cn/showproj.aspx?proj=135827). A total of 26 adult female patients with similar skeletal Class II malocclusions and similar dental and skeletal discrepancies were enrolled. A total of 13 patients in the experimental group received modified PAOO characterized by vertical incisions in interradicular areas and random punching made by a piezoelectric device, whereas 13 patients in the control group received orthodontic treatment only. All patients underwent extraction of four premolars and orthodontic treatment with the sliding MBT straight-wire technique. Treatment courses were recorded and changes in dental and skeletal parameters were evaluated by cephalometric analysis and translated into upper digital cast for further measurements. The results showed that the durations of the alignment and leveling stage (4.51±1.53 mos versus 9.41±1.46 mos. P<0.01), space closing stage (13.56±2.57 mos versus 17.09±3.50 mos. P<0.05) and total treatment course (24.43±2.53 mos versus 31.16±4.17 mos. P<0.01) in the PAOO group were significantly shorter than in the control. The modified PAOO accelerated orthodontic tooth movement in adult extraction cases with skeletal Class II discrepancy and convex profile; the modified PAOO achieved dual goals of periodontal health and long-term stability of orthodontics. Ultimately, this multidisciplinary approach and the use of translational 3D measurements constitute powerful tools that can be used to solve complex clinical problems.

Clinical and histological evaluation of the use of acellular dermal matrix (ADM) membrane in peri-implant vertical soft tissue augmentation: A controlled clinical trial.

OBJECTIVES: The aim of this study was to clinically and histologically evaluate the efficacy of using acellular dermal matrix (ADM) for peri-implant vertical soft tissue augmentation at implant placement. MATERIALS AND METHODS: Twenty patients were enrolled in this study. According to the initial thickness of vertical soft tissue, patients were assigned into the ADM group (≤2 mm) or the control group (>2 mm) prior to implant surgery +ADM grafting or implant surgery alone. Second-stage surgery was carried out 3 months later, and a small piece of ridge membrane was harvested for histological and immunohistochemical evaluation. Vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF)-BB in peri-implant crevicular fluid (PICF) were also assessed 1 week, 1 month, and 5 months after second-stage surgery. Clinical parameters were recorded to evaluate peri-implant health at 1 week and 3 months after implant restoration. RESULTS: All 20 implants healed uneventfully and successfully. Soft tissue thicknesses were comparable in the two groups at second-stage surgery (3.20 ± 0.42 mm vs. 3.50 ± 0.58 mm). In the ADM group, the mean increase in soft tissue thickness was 1.85 ± 0.34 mm. Histological and immunohistochemical outcomes showed no differences between the two groups. VEGF and PDGF-BB levels in PICF were significantly lower in the ADM group 1 week after second-stage surgery (p < .01), yet they decreased in both groups later. The difference between the groups had disappeared by 5 months after second-stage surgery. The clinical peri-implant parameters were good and stable by the end of the study (3 months after restoration). CONCLUSIONS: Our results suggested that using ADM at implant placement was effective in increasing the thickness of peri-implant vertical soft tissue and achieved comparable clinical and histological performance to the control group. However, the incremental soft tissue showed inferior angiogenic ability in the early stage of wound healing.

Comparisons of the killing effect of direct current partially mediated by reactive oxygen species on Porphyromonas gingivalis and Prevotella intermedia in planktonic state and biofilm state - an in vitro study.

BACKGROUND/PURPOSE: Bacterial biofilms formed on the surface of tissues and biomaterials are major causes of chronic infections in humans. Among them, Porphyromonas gingivalis (P. gingivalis) and Prevotella intermedia (P. intermedia) are anaerobic pathogens causing dental infections associated with periodontitis. In this study, we evaluated the killing effect and underlying mechanisms of direct current (DC) as an antimicrobial method in vitro. MATERIALS AND METHODS: We chose P. gingivalis and P. intermedia in different states to make comparisons of the killing effect of DC. By viable bacteria counting, fluorescent live/dead staining, reactive oxygen species (ROS) assay, addition of ROS scavenger DMTU and mRNA expression assay of ROS scavenging genes, the role of ROS in the killing effect was explored. RESULTS: The planktonic and biofilm states of two bacteria could be effectively killed by low-intensity DC. For the killing effect of 1000 µA DC, there were significant differences whether on planktonic P. gingivalis and P. intermedia (mean killing values: 2.40 vs 2.62 log10 CFU/mL) or on biofilm state of those (mean killing values: 0.63 vs 0.98 log10 CFU/mL). 1000 µA DC greatly induced ROS production and the mRNA expression of ROS scavenging genes. DMTU could partially decrease the killing values of DC and downregulate corresponding gene's expression. CONCLUSION: 1000 µA DC can kill P. gingivalis and P. intermedia in two states by promoting overproduction of ROS, and P. intermedia is more sensitive to DC than P. gingivalis. These findings indicate low-intensity DC may be a promising approach in treating periodontal infections.

Downregulating MFN2 Promotes the Differentiation of Induced Pluripotent Stem Cells into Mesenchymal Stem Cells through the PI3K/Akt/GSK-3ß/Wnt Signaling Pathway.

Understanding the mechanism of the differentiation of induced pluripotent stem cells (iPSCs) into mesenchymal stem cells (MSCs) and promoting the production efficiency of iPSC-derived MSCs (iPSC-MSCs) are critical to periodontal tissue engineering. However, the gene networks that control this differentiation process from iPSCs into MSCs are poorly understood. We demonstrated that MFN2 knockdown showed a positive effect on the triploblastic and MSC differentiation from iPSCs. Activation of the PI3K/Akt signaling pathway by MFN2 knockdown activated the Wnt/ß-catenin signaling pathway by inhibiting GSK-3ß and reducing ß-catenin degradation. Inhibitor of the PI3K/Akt signaling pathway normalized the enhanced efficiency of differentiation into MSCs of MFN2-KD iPSCs and Wnt activator-treated control iPSCs. MFN2-OE iPSCs displayed an opposite phenotype. In conclusion, downregulating MFN2 promotes the differentiation of iPSCs into MSCs by activating the PI3K/Akt/GSK-3ß/Wnt signaling pathway. Our results reveal a crucial function and mechanism for MFN2 in regulating MSC differentiation from iPSCs, which will provide new ideas for periodontal tissue engineering and periodontal regenerative treatment by using iPSC-MSCs.