Metabolic profiling of peri-implant crevicular fluid in peri-implantitis.

OBJECTS: This study aims to explore the etiology of peri-implantitis by comparing the metabolic profiles in peri-implant crevicular fluid (PICF) from patients with healthy implants (PH) and those with peri-implantitis (PI). MATERIALS AND METHODS: Fifty-six patients were enrolled in this cross-sectional study. PICF samples were collected and analyzed using both non-targeted and targeted metabolomics approaches. The relationship between metabolites and clinical indices including probing depth (PD), bleeding on probing (BOP), and marginal bone loss (MBL) was examined. Additionally, submucosal microbiota was collected and analyzed using 16S rRNA gene sequencing to elucidate the association between the metabolites and microbial communities. RESULTS: Significant differences in metabolic profiles were observed between the PH and PI groups, with 179 distinct metabolites identified. In the PI group, specific amino acids and fatty acids were significantly elevated compared to the PH group. Organic acids including succinic acid, fructose-6-phosphate, and glucose-6-phosphate were markedly higher in the PI group, showing positive correlations with mean PD, BOP, and MBL. Metabolites that increased in the PI group positively correlated with the presence of Porphyromonas and Treponema and negatively with Streptococcus and Haemophilus. CONCLUSIONS: This study establishes a clear association between metabolic compositions and peri-implant condition, highlighting enhanced metabolite activity in peri-implantitis. These findings open avenues for further research into metabolic mechanisms of peri-implantitis and their potential therapeutic implications.

Predictive factors for the treatment success of peri-implantitis: a protocol for a prospective cohort study.

INTRODUCTION: Peri-implantitis, a common biological complication of dental implant, has attracted considerable attention due to its increasing prevalence and limited treatment efficacy. Previous studies have reported several risk factors associated with the onset of peri-implantitis (eg, history of periodontitis, poor plaque control and smoking). However, inadequate data are available on the association between these risk factors and successful outcome after peri-implantitis therapy. This prospective cohort study aims to identify the local and systemic predictive factors for the treatment success of peri-implantitis. METHODS AND ANALYSIS: A single-centre cohort study will be conducted by recruiting 275 patients diagnosed with peri-implantitis. Sociodemographic variables, healthy lifestyles and systemic disorders will be obtained using questionnaires. In addition, clinical and radiographic examinations will be conducted at baseline and follow-up visits. Treatment success is defined as no bleeding on probing on more than one point, no suppuration, no further marginal bone loss (≥0.5 mm) and probing pocket depth ≤5 mm at the 12-month follow-up interval. After adjustment for age, sex and socioeconomic status, potential prognostic factors related to treatment success will be identified using multivariable logistic regression models. ETHICS AND DISSEMINATION: This cohort study in its current version (2.0, 15 July 2022) is in accordance with the Declaration of Helsinki and was approved by the Ethics Committee of Stomatological Hospital, Southern Medical University (EC-CT-(2022)34). The publication will be on behalf of the study site. TRIAL REGISTRATION NUMBER: ChiCTR2200066262.

Digital workflow for proximal adjustment of teeth adjacent to implant-supported fixed restorations using a predesigned computer-aided grinding guide.

Clinically, the proximal surfaces of teeth adjacent to an implant restoration usually need to be adjusted to build a preferable adjacency relationship. However, it is difficult for freehand preparation to get a favorable proximal contour in some cases. In the workflow presented here, virtual grinding can be made to adjacent teeth, under the consideration of functional reconstruction and biological requirements, and then the grinding can be implemented using digital templates and a specialized bur. This allows for more precise and accurate adjustments to be made during the clinical procedure, reducing the risk of over- or under-preparation of the proximal surfaces. In addition, the use of specialized diamond burs and grinding guides can make the procedure more efficient and streamlined, reducing the time required for proximal adjustment and minimizing patient discomfort. The resulting implant-supported prosthesis is more likely to function properly and last longer, as the precise proximal contacts can help distribute occlusal forces more evenly across the dentition. Overall, the use of digital technology for precise adjustment of proximal contacts during implant restorations represents an important advancement in modern dentistry, enabling dentists to provide their patients with more accurate, efficient, and effective dental care.

Influence of edentulism on the structure and function of temporomandibular joint.

Background: With the acceleration of the aging process of the population, the number of edentulous patients continuously increased. Edentulism induces the loss of occlusal relationship and cause adverse effects on the stomatognathic system. Temporomandibular joint (TMJ), as a significant component of this system, may also be affected by edentulism in the process of supporting mandibular movement. Purpose: Provide a comprehensive review of the structure and function of TMJ in the edentulous population, as well as the prevalence of temporomandibular joint disorder (TMD) in edentulous group. Study selection: An electronic search was conducted on articles prior to December 2022 to filter all papers relevant to the structure and function of TMJ in edentulous population. The internet databases (PubMed, Cochrane Library, Embase) were searched using various combinations of keywords for "edentulism" or "edentulous" and "TMJ" or "TMD". Results: Firstly, 522 articles were selected from the internet database, and finally, a total of 44 articles met the inclusion and exclusion criteria. The research content of these articles mainly focuses on the structure and function of TMJ in edentulous patients, as well as the clinical signs and symptoms of TMD. Conclusions: Edentulous arch induces the loss of occlusal relationship, which may lead to degenerative changes of TMJ components consisting of changes in morphology and bone mass density of condyle, articular fossa, and articular eminence. In addition, the condyle could be shifted backward and upward, and displacement of the articular disc may occur after dentition loss. And the condyle and the articular disc may be guided back to the normal position after effective prosthodontic treatment. But the conclusions of the study on the function of TMJ and the prevalence of TMD in edentulous people are inconsistent. The condition of TMJ, especially the position of condyle-fossa and the symptoms and signs of TMD should not be ignored. If necessary, radiographic examinations should be performed.

Heavy metals in drinking water and periodontitis: evidence from the national oral health survey from China.

BACKGROUND: Periodontitis has become an increasingly important public health issue, coupled with a high economic burden for prevention and treatment. Exposure to essential trace heavy metals has been associated with various diseases; however, the relationships between essential trace heavy metals and periodontitis remain inconclusive. OBJECTIVES: To investigate the association between essential trace heavy metals in tap water and periodontitis in a nationally representative sample in China. METHODS: We conducted a nationwide study including 1348 participants from the Fourth National Oral Health Survey in the 2015-2016 period. The trace heavy metals concentration was measured in the local pipeline terminal tap water. Periodontitis was diagnosed according to the classification scheme proposed at the 2018 world workshop on the classification of periodontal and peri-implant diseases and conditions. We used weighted multivariable logistic regression to estimate the association between essential trace heavy metals and the risk of periodontitis. We additionally used spline analysis to explore the possible nonlinear dose-response associations. RESULTS: Periodontitis patients were exposed to higher concentrations of essential trace heavy metals. In adjusted models, for 1 SD increase in the concentration of iron, manganese, and copper in tap water, the risk of periodontitis increased by 30% (OR: 1.30, 95%CI: 1.12-1.50), 20% (OR: 1.20, 95%CI: 1.03-1.41), and 20% (OR: 1.20, 95%CI: 1.04-1.39), respectively. Stratified analyses demonstrated that the associations between essential trace heavy metals and periodontitis were higher in females, elders, and rural residents. Spline analysis revealed nonlinear exposure-response relationships between periodontitis and exposure to iron, manganese, and copper in tap water. CONCLUSIONS: Exposures to essential trace heavy metals in drinking water were associated with greater odds of periodontitis. Given the growing burden of periodontitis, our study sheds light on tailored public health policies for improving drinking water standards to alleviate periodontitis impairment.

Comparison of the inflammatory states of serum and gingival crevicular fluid in periodontitis patients with or without type 2 diabetes mellitus.

Background/purpose:There is a two-way relationship between periodontitis and type 2 diabetes mellitus. This study aimed to compare the inflammatory states in serum and gingival crevicular fluid (GCF) in periodontitis patients with or without type 2 diabetes mellitus (T2DM) and healthy subjects. Materials and methods: 20 subjects were systematic and periodontal healthy (H group), 40 subjects were with periodontitis (CP group), and other 40 were with periodontitis and type 2 diabetes mellitus (DC group). Fasting blood glucose (FBG) and HbA1c was tested. GCF and serum level of interleukin (IL) -17, visfatin, receptor activator of nuclear factor-kappa B (NF-κB) ligand (RANKL)/osteoprotegerin (OPG) ratio were measured. Results: The GCF volume, total amount of IL-17, vastatin, RANKL/OPG ratio in GCF and their concentrations in serum were higher (P < 0.05) in CP and DC groups than in H group, which were also higher (P < 0.05) in DC group than in CP group except for visfatin in GCF and IL-17 in serum. At sample sites of PD ≤ 3 mm, GCF volume, IL-17, visfatin and RANKL/OPG ratio in DC and CP groups were higher (P < 0.05) than that in H group, which were also higher in DC group than in CP group either with PD ≤ 3 mm or PD > 3 mm. Inflammatory state in GCF was positively correlated to systemic inflammation, and both of them were positively correlated to FBG. Conclusion: Moderate and severe periodontitis aggravated systemic inflammation. T2DM together with periodontitis resulted in more severe systemic inflammation. The positive correlation between the periodontal and systemic inflammation and their association with FBG indicated an inflammatory link between periodontitis and T2DM.

Application of functionalized hyaluronic acid hydrogel with the activity of regulating the behaviors of stem cells in repairing rabbit knee articular cartilage.

Using injectable hydrogels loaded with mesenchymal stem cells (MSCs) to repair chondral defects is a new trend of cartilage tissue engineering in recent years. In this study, hyaluronic acid (HA) hydrogels containing the system of sustained-release Kartogenin (KGN) and modified by RGD and HAV peptides were used to facilitate repair of cartilage defect in the knee joint of rabbits. Different groups of implants were injected into osteochondral defects, and samples were taken 4 weeks after operation. Through the qualitative and quantitative analysis of Micro-CT, it can be seen that both FH (unloaded cell group) and R + FH groups (allogeneic cell group) can repair osteochondral defects well, and the amount of bone formation is high, which is close to the intact cartilage groups. Macroscopic observation and histological staining analysis showed that except for the intact cartilage group, FH group obtained the highest score. The morphology of the cartilage tissue in the FH groups was more regular and continuous than that in R + FH and H + FH (xenogeneic cell group) groups, approaching that of native cartilage. Immunohistochemical staining of Collagen II (Col II) showed that the expression and morphology of Col II in FH groups were similar to those in intact cartilage tissue. Interestingly, through in vivo experiments, this functionalized hyaluronic acid hydrogel can effectively promote the rapid repair of rabbit knee cartilage defects within one month.

The Characteristics of Microbiome and Cytokines in Healthy Implants and Peri-Implantitis of the Same Individuals.

AIM: To characterize the profile of submucosal microbiome and cytokine levels in peri-implant crevicular fluid (PICF) from clinically healthy implants and peri-implantitis in the same individuals. MATERIAL AND METHODS: A total of 170 patients were screened and, finally, 14 patients with at least one healthy implant and one peri-implantitis implant were included. Submucosal microbiota and cytokines from 28 implants were analyzed using 16S rRNA gene sequencing and multifactor assays, respectively. Correlations of clinical indexes and microbiota or cytokines were analyzed using Spearman's correlation coefficient. A random forest classification model was constructed. RESULTS: Peri-implantitis sites harbored higher microbial diversity, as well as more Gram-negative bacteria and anaerobic bacteria, compared with healthy implants sites. The genera of Peptostreptococcaceae XIG-1, Treponema, Porphyromonas, and Lachnospiraceae G-8, as well as the cytokines of IL-17A, IL-6, IL-15, G-CSF, RANTES, and IL-1ß were significantly higher in peri-implantitis than healthy implants. Furthermore, these genera and cytokines had positive relationships with clinical parameters, including probing depth (PD), bleeding on probing (BOP), and marginal bone loss (MBL). The classification model picked out the top 15 biomarkers, such as IL-17A, IL-6, IL-15, VEGF, IL-1ß, Peptostreptococcaceae XIG-1, Haemophilus, and Treponema, and obtained an area under the curve (AUC) of 0.85. CONCLUSIONS: There are more pathogenic bacteria and inflammatory cytokines in peri-implantitis sites, and biomarkers could facilitate the diagnosis of peri-implantitis.

Interactions of periodontal pathogens with platelets in the gingival crevicular fluid of patients with periodontitis.

AIM: To explore the immunological defensive effects of platelets on periodontal pathogens in the gingival crevicular fluid (GCF). MATERIALS AND METHODS: GCF samples were collected from 20 patients with periodontitis and 10 healthy controls. Platelets in the GCF were detected by immunocytochemistry and immunofluorescence. Isolated platelets from healthy volunteers were co-cultured with Porphyromonas gingivalis (Pg) and Fusobacterium nucleatum (Fn). The interactions between platelets and periodontal pathogens were observed by transmission and scanning electron microscopy. The isolated platelets plus neutrophils were co-cultured with Pg or Fn, and the formation of neutrophil extracellular traps (NETs) was evaluated by staining with Sytox Green. RESULTS: The platelet level in the GCF was higher in patients with periodontitis than in healthy controls. Platelets interacted with bacteria and neutrophils in the GCF. In vitro, platelets recruited and engulfed periodontal pathogens. In response to periodontal pathogens, neutrophils released web chromatin, and platelets promoted the formation of intensive NETs. CONCLUSIONS: Platelets, migrating to the gingival sulcus, may exert direct antibacterial effects or assist neutrophils.

Effect of adjunctive systemic antibiotics on microbial populations compared with scaling and root planing alone for the treatment of periodontitis: A pilot randomized clinical trial.

BACKGROUND: To investigate the microbial shift after periodontitis being treated by scaling and root planing (SRP) with or without adjunctive antibiotics, and to assess the relationship between oral microbiota and systemic factors. METHODS: A 6-month pilot randomized controlled trial recruited 14 subjects with severe periodontitis, divided into test group and control group to receive full-mouth SRP with or without amoxicillin (500 mg) and metronidazole (200 mg) (three times a day for 7 days). Clinical examination, collection of subgingival plaque and saliva, and blood tests were performed at baseline pre-treatment, 3 months, and 6 months post-treatment. The V3V4 region of 16S DNA was sequenced; taxonomic assignment was based on the Human Oral Microbiome Database. RESULTS: The periodontal condition significantly improved in both groups; the test group showed a greater improvement in plaque index, probing depth, and bleeding index than the control group. The test group demonstrated significantly lower microbial richness and diversity, and less abundant Porphyromonas than the control group at 3 months for both subgingival microbiome and salivary microbiome. However, the microbial differences narrowed within 6 months. The subgingival and salivary microbiota shifted synergistically. Glucose was positively related to subgingival Porphyromonas; mean platelet volume was positively related to subgingival Leptotrichia. CONCLUSIONS: Systemic administration of amoxicillin and metronidazole along with SRP had an advantage over SRP alone in clinical improvement and infection control in both the subgingival region and saliva 3 months post-treatment. Microbial advantage nearly disappeared at 6 months; however, the clinical advantage lasted longer. The use of antibiotics also has potential benefits for systemic inflammation and glucose.

The occurrence of peri-implant mucositis associated with the shift of submucosal microbiome in patients with a history of periodontitis during the first two years.

AIM: To investigate the dynamic changes of peri-implant microbiome in patients with a history of periodontitis and to construct a microbial prediction model. MATERIALS AND METHODS: The prospective study was performed at one month (T1), one year (T2) and two years (T3) after restoration. Clinical examinations [probing depth (PD), bleeding on probing (BOP), suppuration (SUP)], radiographic examinations and sample collection were conducted at three timepoints. Peri-implant sulcular fluid (PISF) was collected and analysed by 16S rRNA gene sequencing. Generalized linear mixed model (GLMM) was used to identify differences. RESULTS: Totally, 168 subjects were assessed for eligibility. Twenty-two patients were recruited in the longitudinal study. Eventually, 67 PISF samples from 24 implants of 12 patients were collected and analysed. Peri-implant microbiome showed increasing diversity and complexity over time. Disease-associated genera Porphyromonas, Tannerella, Treponema and Prevotella dramatically increased from T1 to T3. The prediction model for clinical suppuration at T1 showed a high accuracy of 90%. CONCLUSION: The dysbiosis of peri-implant microbiome increased with time during the two-year observation in patients with a history of periodontitis. Genera of Porphyromonas, Tannerella, Treponema and Prevotella were biomarkers of peri-implant mucositis. Microbiota at the early stage could predict subsequent microbial dysbiosis and clinical suppuration.

Functional characterization of a starch synthesis-related gene AmAGP in Amorphophallus muelleri.

AMORPHOPHALLUS: has attracted tremendous interest because of its high contents of glucomannan and starch. Very few genes regulating glucomannan and starch were reported in Amorphophallus. In this study, an ADP-glucose pyrophosphorylase (AGP) gene that plays a significant role in plant starch synthesis was cloned from Amorphophallus muelleri. It was shown that it encoded a predicted protein containing a conserved plant ADP-Glucose-PP repeat domain and seven potential ligand-binding sites. The real-time quantitative PCR showed that AmAGP was most abundant in tubers, and it was positively correlated with starch content. Additionally, its influencers about temperature and exogenous plant hormone were also discussed, showing that AmAGP expressed highly in tubers under treatments using 25°C and IAA. Furthermore, starch content was closely related to AmAGP expression level, suggesting that AmAGP was involved in the regulation of starch synthesis in A. muelleri. Therefore, identifying the sequence of AmAGP and its expression pattern during tuber enlarging and the changes of its transcript levels in response to temperature and plant hormones would contribute to a better understanding of starch synthesis, and also providing a reference information for future preferable breeding for obtaining more starch or more glucomannan in Amorphophallus.

Well-maintained patients with a history of periodontitis still harbor a more dysbiotic microbiome than health.

BACKGROUND: It remains unclear whether well-maintained subjects, with periodontitis in the past, effectively treated, and maintained for a long time, have the same subgingival microbiome as healthy subjects. Therefore, the objective of this study was to investigate the characteristics of the subgingival microbiome in well-maintained patients with a history of periodontitis compared with healthy subjects. METHODS: We recruited in 17 well-maintained individuals (no evidence of clinical inflammation and progress of periodontitis) and 21 healthy individuals. Periodontal clinical parameters, consisting of missing teeth, plaque index (PLI), periodontal depth (PD), and bleeding index (BI), were recorded and analyzed. The pooled subgingival samples from mesiobuccal sites of two maxillary first molars were collected. The V3-V4 region of 16S rRNA gene from 38 subgingival samples was sequenced and analyzed. Alpha diversity, microbial composition, types of bacteria, functional pathways between well-maintained group and health group were compared using Mann-Whitney U test. Spearman correlation was used in analyzing the symbiotic relationship among taxa. A classification model was constructed to distinguish two ecological types. RESULTS: The maintained individuals demonstrated a different microbiome from healthy subjects, with higher diversity, more disordered structure, more pathogenic microbiota, and more host-destructive metabolism pathways. The genera Actinomyces, Streptococcus, Leptotrichia, Capnocytophaga, Lautropia, and Fusobacterium were predominant components with relative abundance >5% in the subgingival microbiome of well-maintained patients. The classification model by microbiota got a remarkable accuracy of 83.33%. CONCLUSIONS: Individuals with well-maintained periodontitis showed a more dysbiotic microbial community than healthy individuals. Therefore, close monitoring and scheduled maintenance treatment are necessary for them to maintain a healthy periodontal condition.

Peri-implant mucositis sites with suppuration have higher microbial risk than sites without suppuration.

BACKGROUND: The aims of the present study were to compare the microbial differences between peri-implant mucositis sites with or without suppuration, and to construct a classification model with microbiota. METHODS: Twenty-four implants with peri-implant mucositis were divided into suppuration (SUP) group and non-suppuration (Non-SUP) group. Clinical assessments of bleeding index, probing depth, suppuration following probing (SUP) were recorded. Submucosal samples were collected from mesiobuccal sites and distobuccal sites, and analyzed by 16S rRNA gene sequencing. Generalized linear mixed model was used to adjust age, gender, location of implants, and intraindividual correlation. RESULTS: It was demonstrated that the microbial richness was lower in SUP group. The relative abundance of some pathogenic taxa, such as genera of Fusobacterium, Tannerella, and Peptostreptococcus, were significantly higher in SUP group than Non-SUP group. In addition, SUP group had less Gram-positive bacteria, aerobic bacteria, and more metabolic pathway related to life activity. The classification model constructed with 12 genera got a 100% accuracy in identifying sites with or without suppuration. CONCLUSIONS: The results from this study demonstrate a higher pathogenicity of microbiome at peri-implant mucositis sites with suppuration than without suppuration, which supports suppuration as a clinical indicator for higher microbial risk.

A three-year study on periodontal microorganisms of short locking-taper implants and adjacent teeth in patients with history of periodontitis.

OBJECTIVE: To analyze the change of six periodontal pathogens around short locking-taper implants and adjacent teeth in patients with different periodontal conditions for three years. METHODS: Sixty implants and 62 adjacent teeth from 24 patients with different periodontal conditions were included: 5 patients with history of aggressive periodontitis (AgP group), 14 patients with history of chronic periodontitis (CP group), and 5 patients with healthy condition or slight gingivitis (H group). Subgingival samples were collected at five timepoints: before implant placement (T1); before second stage operation (T2); one month after restoration (T3); one year after functional loading (T4) and two years after functional loading (T5). Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, Fusobacterium nucleatum, Prevotella intermedia, and Aggregatibacter actinomycetemcomitans were detected by polymerase chain reaction (PCR). RESULTS: Pathogens were hardly found around implants or adjacent teeth until T4. The detection rates of five pathogens other than A. actinomycetemcomitans raised up from T3 to T5. F. nucleatum and P. gingivalis were mostly detected followed by P. intermedia, T. forsythia, and T. denticola. The detection rate of P. gingivalis in implants were higher than natural teeth. There was significant correlation between pathogenic bacteria from implants and adjacent teeth. A. actinomycetemcomitans were only detected positively in peri-implant sites of AgP group. Peri-implantitis sites showed significantly higher detection rates of T. denticola, F. nucleatum at T4, and P. gingivalis, F. nucleatum at T5 than peri-implant mucositis and healthy groups. CONCLUSION: This three-year longitudinal study demonstrated that periodontal pathogens accumulate over time around short locking-taper implants and adjacent natural teeth after restoration. Adjacent teeth may become the microbial reservoir for peri-implant bacteria. Therefore, periodontally compromised patients may face higher risk for peri-implant disease. CLINICAL SIGNIFICANCE: Plaque control of implant should be intensified with time instead of diminished. Patients with history of periodontitis need more frequent and individualized implant maintenance. Treatment and maintenance for adjacent teeth is as important as for implants..

Microbiome in maintained periodontitis and its shift over a single maintenance interval of 3 months.

AIM: To assess the subgingival microbial shift of maintained periodontitis treated by ultrasonic scaling (US) or air polishing (AP) during a 3-month maintenance interval. MATERIALS AND METHODS: We conducted a 12-week randomized split-mouth controlled trial with US and AP in 17 maintained subjects (bleeding on probing [BOP%] ≤25%, probing depth [PD] ≤5 mm). They were monitored at baseline, week 2, week 8 and week 12. The V3-V4 region of the 16S rDNA from 136 subgingival plaque samples was sequenced and analysed. RESULTS: Treatment by US or AP could effectively reduce the PD, microbial richness, diversity, periodontitis-associated microbiota and pathogenic metabolism in maintained periodontitis. Bacteria recolonized after treatment and returned to the pre-treatment level 12 weeks after treatment. Ultrasonic scaling group demonstrated slight advantage in reducing BOP (%), pathogenic bacteria and metabolism than AP group. Pathogenic microbiota and commensal microbiota kept a balance in subgingival community of maintained patients during the 3-month interval. CONCLUSIONS: Treatment by US or AP effectively reduced the pathogenicity of subgingival microbiome by reducing microbial diversity, proportion of periodontitis-associated microbiota and pathogenic metabolism. It helped to keep a balanced subgingival community and stable periodontal condition over a single maintenance interval of 3 months.

Butyrate rather than LPS subverts gingival epithelial homeostasis by downregulation of intercellular junctions and triggering pyroptosis.

AIM: To investigate the effects of sodium butyrate (NaB) and lipopolysaccharide (LPS) on gingival epithelial barrier. MATERIAL AND METHODS: We cultured human primary gingival epithelial cells and investigated the effects of NaB and LPS on gingival epithelial barrier and involved mechanisms at in vitro and in vivo levels by immunostaining, confocal microscopy, field emission scanning electron microscopy (FE-SEM), transmission electronic microscopy (TEM), transepithelial electrical resistance (TEER), FTIC-dextran flux, flow cytometry, real-time PCR and Western blot assays. RESULTS: Our results showed that NaB, rather than LPS, destroyed the epithelial barrier by breaking down cell-cell junctions and triggering gingival epithelial cell pyroptosis with characteristic morphological changes, including swollen cells, large bubbles, pore formation in the plasma membrane and subcellular organelles changes. The upregulated expression of pyroptosis-related markers, caspase-3 and gasdermin-E (GSDME) contributed to this effect. Pyroptosis aroused by NaB is a pro-inflammatory cell death. Pyroptotic cell death provoked inflammatory responses by upregulation of IL-8 and MCP-1, and releasing intracellular contents into the extracellular microenvironment after pyroptotic rupture of the plasma membrane. CONCLUSIONS: Our new findings indicate that butyrate is a potent destructive factor of gingival epithelial barrier and pro-inflammatory mediator, which shed a new light on our understanding of periodontitis initiation.

The effect of supragingival glycine air polishing on periodontitis during maintenance therapy: a randomized controlled trial.

BACKGROUND: Glycine air polishing has been proved to be safe, comfortable and time-saving. Whether it could substitute ultrasonic scaling to remove dental plaque biofilm during periodontal maintenance remains unclear. The purposes of this study were to evaluate the effect of supragingival glycine air polishing (SGAP) on the subgingival periodontal pathogens during maintenance therapy and to check the association of periodontal pathogens and clinical parameters. METHODS: Twenty-three chronic periodontitis patients during their maintenance therapy were enrolled in the 12-week study. According to randomized split-mouth design, the test side was treated with SGAP (65 µm), while the control side was treated with supragingival ultrasonic scaling and polishing (SUSP) with rubber cup. Clinical examination including plaque index (PLI), probing depth (PD), bleeding index (BI) were performed at baseline and 12 weeks post-treatment. Sampling of the subgingival plaque at each investigational site (mesiobuccal site of the mandibular first molar) was performed at baseline and 2, 4, 8, 12 weeks after maintenance treatment. Four periodontal pathogens including Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola and Fusobacterium nucleatum were detected by 16S rDNA polymerase chain reaction. RESULTS: Clinical status generally improved after treatment in both groups. PLI in both groups, PD in SGAP group and bleeding on probing (%) in SUSP group significantly decreased after treatment (p < 0.05). There was no significant difference of clinical parameters between two groups before and after treatment. The detection rates of P. gingivalis, T. denticola in both groups, T. forsythia in SUSP group and F. nucleatum in SGAP group decreased after maintenance treatment in both groups, although no significant difference was found, and it rebound to baseline level at 12 weeks after maintenance treatment. There was no significant difference between SGAP group and SUSP group at any time point. T. denticola-positive sites had significantly greater BI than T. denticola-negative sites (p < 0.05). DISCUSSION: Supragingival glycine air polishing had a reliable effect in removing subgingival dental plaque biofilm during maintenance period, and three months may be a proper maintenance interval for pockets not more than 5 mm.