The influence of different extraction indications on the morphological changes in the maxillary sinus: A retrospective cohort study.

AIMS: The comprehensive effects of maxillary posterior tooth extraction on the maxillary sinus (MS) morphology remain to be thoroughly elucidated. This retrospective cohort study aimed at evaluating the influence of different extraction indications on the morphological changes in the MS by utilizing cone-beam computed tomography (CBCT). METHODS: One hundred and seventy-eight of maxillary posterior tooth extractions underwent CBCT scans before and after extraction using 3D Slicer software. Parameters such as maxillary sinus pneumatization (MSP, the primary outcome measure), buccal bone height (BBH), palatal bone height (PBH), mucosal thickness (MT), and other anatomical structures were measured for patients undergoing extraction due to periodontitis, periapical lesions, or tooth fracture. Multiple linear regression analysis was employed to assess the effect of extraction indications on the MS. RESULTS: While the primary outcome, MSP, did not reveal statistically significant differences across various indications for tooth extraction (p > .05), extraction itself resulted in MSP (p < .05). The rate of this pneumatization was influenced by the position of the extraction site (p < .05). Additionally, baseline values of bone height and mucosal thickness showed an inverse correlation with the rate of change in these parameters following tooth extraction (p < .001). CONCLUSIONS: Tooth extraction led to increased pneumatization of the maxillary sinus while simultaneously reducing bone height and mucosal thickness. However, these outcomes were not influenced by the reason for tooth extraction.

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.

A combination technique of strip free gingival grafts and xenogeneic collagen matrix in augmenting keratinized mucosa around dental implants: a single-arm clinical trial.

BACKGROUND: The aim of this study was to assess the outcomes of the combination technique of strip free gingival grafts (SFGG) and xenogeneic collagen matrix (XCM) in augmenting the width of keratinized mucosa (KMW) around dental implants, and compare its efficacy with the historical control group (FGG). METHODS: Thirteen patients with at least one site with KMW ≤ 2 mm after implant surgery were included and received SFGG in combination with XCM. Another thirteen patients with the same inclusion and exclusion criteria from the previous trial received FGG alone. The same outcomes as the previous trial were evaluated. KMW, thickness of keratinized mucosa (KMT), gingival index (GI) and probing depth (PD) were measured at baseline, 2 and 6 months. Postoperative pain, patient satisfaction and aesthetic outcomes were also assessed. RESULTS: At 6 months after surgery, the combination technique could attain 3.3 ± 1.6 mm of KMW. No significant change could be detected in GI or PD at 6 months compared to those at 2 months (p > 0.05). The postoperative pain and patient satisfaction in VAS were 2.6 ± 1.2 and 9.5 ± 1.2. The total score of aesthetic outcomes was 3.8 ± 1.2. In the historical FGG group, 4.6 ± 1.6 mm of KMW was reported at 6 months, and the total score of aesthetic outcomes was higher than the combination technique (4.8 ± 0.7 vs. 3.8 ± 1.2, p < 0.05). CONCLUSIONS: The combination technique of SFGG and XCM could increase KMW and maintain peri-implant health. However, this combination technique was associated with inferior augmentation and aesthetic outcomes compared with FGG alone. TRIAL REGISTRATION: This clinical trial was registered in the Chinese Clinical Trial Registry with registration number ChiCTR2200057670 on 15/03/2022.

Decellularized matrix could affect the proliferation and differentiation of periodontal ligament stem cells in vitro.

OBJECTIVE AND BACKGROUND: Recently, decellularized matrix (DCM) is considered as a new biomaterial for tissue regeneration. To explore the possible application of DCM in periodontal regeneration, the effect of DCM from three different cells on the proliferation and differentiation of human periodontal ligament stem cells (PDLSCs) was investigated. METHODS: DCM derived from human periodontal ligament cells (PDLCs), dental pulp cells (DPCs), and gingival fibroblasts (GFs) were fabricated using Triton X-100/NH4 OH combined with DNase I. Allogeneic PDLSCs were cultured on PDLC-DCM, DPC-DCM, and GF-DCM, respectively. The proliferative capacity of PDLSCs was evaluated by PicoGreen assay kit. The expression of alkaline phosphatase (ALP), runt-related transcription factor-2 (RUNX2), osteocalcin (OCN), collagen I (COL1), periostin (POSTN), and cementum protein 1 (CEMP1) were detected by qRT-PCR and western blotting. RESULTS: PDLC-DCM, DPC-DCM, and GF-DCM had similar and integrated networks of extracellular matrix, as well as significantly decreased DNA content. Compared with control group in which PDLSCs were directly seeded in culture plates, PDLC-DCM, DPC-DCM, and GF-DCM promoted the proliferation of re-seeded PDLSCs. Additionally, PDLSCs on DCM exhibited higher mRNA and protein expression levels of ALP, RUNX2, OCN, and COL1. The expression of POSTN in PDLC-DCM group was significantly higher than control group at both mRNA and protein levels. CONCLUSIONS: PDLC-DCM, DPC-DCM, and GF-DCM could enhance the proliferation of PDLSCs. PDLC-DCM facilitated osteogenic differentiation and periodontal ligament differentiation of PDLSCs, while DPC-DCM and GF-DCM promoted osteogenic differentiation.

Clinical evaluation of xenogeneic collagen matrix versus free gingival grafts for keratinized mucosa augmentation around dental implants: A randomized controlled clinical trial.

AIM: To evaluate the outcomes of an apically repositioned flap (ARF) plus xenogeneic collagen matrix (XCM) in augmenting keratinized mucosa width (KMW) around dental implants when compared with ARF plus free gingival grafts (FGG). MATERIALS AND METHODS: Twenty-six participants with at least one site with KMW ≤2 mm were randomized into FGG or XCM group. Clinical examinations were performed at baseline and at 2 and 6 months after surgery, including KMW, keratinized mucosa thickness, gingival index (GI), and probing depth (PD). Post-operative pain and patient satisfaction were also evaluated. RESULTS: At 6 months, FGG attained a greater increase of KMW and thicker mucosa than XCM (4.1 ± 1.6 mm vs. 1.8 ± 1.0 mm, p < .001; 1.7 ± 0.6 mm vs. 1.2 ± 0.3 mm, p < .01). Regarding GI, PD, post-operative pain, aesthetic outcomes, and patient satisfaction, no significant difference could be detected. Moreover, the operation time of XCM group was shorter (60 ± 9 min vs. 39 ± 8 min, p < .001). CONCLUSIONS: FGG could result in greater increase of KMW than XCM, though both could increase KMW, maintain peri-implant health, and attain comparable aesthetic outcomes. The use of XCM was associated with reduced operation time.

Efficacy of nano-carbonate apatite dentifrice in relief from dentine hypersensitivity following non-surgical periodontal therapy: a randomized controlled trial.

BACKGROUND: Dentine hypersensitivity (DH) could occur or intensify after non-surgical periodontal therapy because of the exposure of dentine tubules, but currently no gold standard exists to treat DH. It has been demonstrated that nano-sized particles presented potential for dentine tubules blocking and remineralization. This randomized controlled trial aimed to investigate the efficacy of dentifrice containing nano-carbonate apatite (n-CAP) in reducing dentine hypersensitivity (DH) after non-surgical periodontal therapy. METHODS: 48 periodontitis patients with DH were included in this clinical trial. After non-surgical periodontal therapy, patients included were randomized to test and control group and the respective dentifrices were applied at chairside, after which they were instructed to brush teeth with the allocated dentifrices twice a day at home. Periodontal parameters were recorded at baseline and the last follow-up. DH was measured by air-blast test and recorded by visual analogue scale (VAS) and Schiff sensitivity scale at baseline, after polishing (0 week) and 2/4/6 weeks. RESULTS: 45 participants completed the follow-up. Periodontal parameters were improved and comparable between groups. Significant reduction in DH was observed in both groups at all time-points compared to baseline in terms of VAS and Schiff score. The test group achieved significantly greater relief from hypersensitivity compared with the control group after 4-week at-home use (for change of VAS, test group: 2.27 ± 2.47 versus control group: 1.68 ± 2.24, p = 0.036; for change of Schiff, test group: 0.94 ± 0.92 versus control group: 0.61 ± 0.83, p < 0.001). The 6-week results showed borderline significance between groups in terms of change of Schiff (p = 0.027) and no significance in terms of change of VAS (p = 0.256). CONCLUSIONS: Home-use of n-CAP based dentifrice had some benefit on alleviation of DH following non-surgical periodontal therapy after 4 weeks compared to the control product. TRIAL REGISTRATION: Chinese Clinical Trials Registry (No. ChiCTR-IPR-17011678, http://www.chictr.org.cn/, registered 16 June, 2017).

Long-term stability of root coverage procedures for single gingival recessions: A systematic review and meta-analysis.

AIM: To evaluate the long-term (≥2 years) stability of root coverage procedures for single gingival recessions. MATERIALS AND METHODS: A complete literature search was performed up to July 2018. Randomized controlled trials (RCTs) following ≥2 years were selected. Primary outcomes were complete root coverage (CRC) and mean root coverage (MRC). Secondary outcomes were width of keratinized tissue (KTW) and patient-centred parameters. Meta-analysis was conducted when possible. RESULTS: A total of fifteen RCTs were included. The results demonstrated significantly higher MRC in short-term than long-term after coronally advanced flap (CAF; 7.29%, p = 0.006). When CAF combined with connective tissue graft (CTG), no significant difference was observed in CRC or MRC for short-term versus long-term (1.00, p = 0.97; 2.35%, p = 0.09), and it resulted in better long-term efficacy than CAF alone in terms of CRC (0.69, p = 0.0006) and KTW (-0.63 mm, p = 0.04). For CAF plus enamel matrix derivative, the meta-analysis showed no significant difference between the short-term and long-term results of CRC (1.26, p = 0.21). CONCLUSIONS: CAF alone could result in decreased postoperative percentage of root coverage with time. CAF + CTG could maintain long-term stability and result in better root coverage outcomes than CAF.

Efficacy of xenogeneic collagen matrix in the treatment of gingival recessions: A systematic review and meta-analysis.

OBJECTIVES: This review aims to evaluate the efficacy of xenogeneic collagen matrix (XCM) for the treatment of single or multiple gingival recessions in terms of clinical parameters and patient-related outcomes. MATERIALS AND METHODS: Various electronic databases (The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, etc.) from 1966 to April 2018 and hand literatures were searched. Quality of the included studies was assessed through the Cochrane Collaboration's Risk of Bias tool. A meta-analysis was performed to calculate risk ratios and mean differences. RESULTS: Nine randomized controlled trials were included. The results revealed a higher percentage of mean root coverage (MRC) and a greater recession reduction (RecRed) for single recessions for the combination of coronally advanced flap (CAF) with XCM compared to CAF alone (n = 3; MD = 10.00%; 95%CI [3.56%; 16.43%]; p = 0.002) (n = 3; MD = 0.35 mm; 95%CI [0.10 mm; 0.60 mm]; p = 0.005). Comparing XCM with connective tissue graft (CTG), no significant differences were detected in MRC or RecRed for single and multiple recessions. CONCLUSIONS: The addition of XCM under CAF could improve MRC and RecRed at single tooth recessions. Initial data suggest that XCM shows promising results to improve the clinical efficacy of CAF for multiple recessions. In addition, XCM could be a valid alternative to CTG in terms of MRC and RecRed at both single and multiple recessions. Based on limited evidence, XCM may decrease postoperative morbidity and operation time compared to CTG.

Effect of alveolar ridge preservation at periodontally compromised molar extraction sockets: A retrospective cohort study.

BACKGROUND: To date, the clinical evidence regarding the effectiveness of alveolar ridge preservation (ARP) in restricting alveolar bone height and width change after extraction at periodontally compromised molar extraction sockets still remains controversial. This retrospective cohort study aims to evaluate the effect of ARP in molars extracted for periodontal reasons. METHODS: Retrospective data were collected from patient electronic records from January 2019 to December 2023. Patients with Stage III/IV periodontitis who underwent extraction of molars for periodontal reasons were screened for eligibility. The outcomes included the horizontal and vertical dimensions of alveolar bone. The need for additional augmentation procedure during implantation was also evaluated. A linear regression model was used to adjust for known confounders. RESULTS: A total of 80 sockets were included in this study, of which 27 sockets received ARP therapy after extraction while 53 sockets experienced natural healing (NH). ARP resulted in significantly less bone height change in the periodontally compromised molar sites compared to the NH group (p < 0.001). In sockets displaying a height disparity of >2 mm between the buccal and palatal/lingual walls, the ARP group exhibited advantageous outcomes in terms of ridge width change, surpassing the NH group (p = 0.004). Moreover, the percentage for additional augmentation was significantly reduced in the ARP compared to the NH group (p = 0.006). Age, sex, smoking, jaw, location, and buccal wall thickness did not show any significant effect on bone height change. CONCLUSION: ARP had benefits on limiting ridge resorption subsequent to molar extraction for periodontal reasons.

Clinical relevance of distolingual roots and periodontal status in mandibular first molars: a cross-sectional study employing CBCT analysis. / ä¸‹é¢Œç¬¬ä¸€ç£¨ç‰™è¿œèˆŒæ ¹çš„å­˜åœ¨ä¸Žç‰™å‘¨çŠ¶æ€çš„ä¸´åºŠç›¸å ³æ€§åˆ†æžï¼šä¸€é¡¹é‡‡ç”¨é”¥å½¢å°„æŸç”µè„‘æ–­å±‚æ‰«æåˆ†æžçš„æ¨ªæ–­é¢ç ”ç©¶.

OBJECTIVES: Distolingual root of the permanent mandibular first molar (PMFM-DLR) has been frequently reported, which may complicate the treatment of periodontitis. This study aimed to assess the morphological features of PMFM-DLR and investigate the correlation between the morphological features of PMFM-DLR and periodontal status in patients with Eastern Chinese ethnic background. MATERIALS AND METHODS: A total of 836 cone beam computed tomography (CBCT) images with 1497 mandibular first molars were analyzed to observe the prevalence of PMFM-DLR at the patients and tooth levels in Eastern China. Among them, complete periodontal charts were available for 69 Chinese patients with 103 teeth. Correlation and regression analyses were used to evaluate the correlation between the morphological features of DLR, bone loss, and periodontal clinical parameters, including clinical attachment loss (CAL), probing pocket depth (PPD), gingival recession (GR), and furcation involvement (FI). RESULTS: The patient-level prevalence and tooth-level prevalence of DLR in mandibular first molars were 29.4% and 26.3%, respectively. Multiple linear regression analysis suggested that bone loss at the lingual site and CAL were negatively affected by the angle of separation between distolingual and mesial roots in the transverse section, while they were significantly influenced by age and the angle of separation between distobuccal and mesial roots in the coronal section. CONCLUSIONS: The prevalence of PMFM-DLR in Eastern China was relatively high in our cohort. The morphological features of DLR were correlated with the periodontal status of mandibular first molars. This study provides critical information on the morphological features of DLR for improved diagnosis and treatment options of mandibular molars with DLR.

Collagen-based scaffolds with high wet-state cyclic compressibility for potential oral application.

Soft tissue substitutes have been developed to treat gingival recessions to avoid a second surgical site. However, products of pure collagen for clinical application lack their original mechanical strengths and tend to degrade fast in vivo. In this study, a collagen-based scaffold crosslinked with oxidized sodium alginate (OSA-Col) was developed to promote mechanical properties. Compared with commercial products collagen matrix (CM) and collagen sponge (CS), OSA-Col scaffolds presented higher wet-state cyclic compressibility, early anti-degradation ability, similar hemocompatibility and cytocompatibility. Furthermore, in the subcutaneous implantation experiment, OSA2-Col3 scaffolds showed better anti-degradation performance than CS scaffolds and superior neovascularization than CM scaffolds. These results demonstrated that OSA2-Col3 scaffolds had potential as a new soft tissue substitute for the treatment of gingival recessions.

Interaction Between Autophagy and Porphyromonas gingivalis-Induced Inflammation.

Autophagy is an immune homeostasis process induced by multiple intracellular and extracellular signals. Inflammation is a protective response to harmful stimuli such as pathogen microbial infection and body tissue damage. Porphyromonas gingivalis infection elicits both autophagy and inflammation, and dysregulation of autophagy and inflammation promotes pathology. This review focuses on the interaction between autophagy and inflammation caused by Porphyromonas gingivalis infection, aiming to elaborate on the possible mechanism involved in the interaction.

Inflamm-Aging-Related Cytokines of IL-17 and IFN-γ Accelerate Osteoclastogenesis and Periodontal Destruction.

Periodontal disease (PD), as an age-related disease, prevalent in middle-aged and elderly population, is characterized as inflammatory periodontal tissue loss, including gingival inflammation and alveolar bone resorption. However, the definite mechanism of aging-related inflammation in PD pathology needs further investigation. Our study is aimed at exploring the effect of inflamm-aging-related cytokines of interleukin-17 (IL-17) and interferon-γ (IFN-γ) on osteoclastogenesis in vitro and periodontal destruction in vivo. For receptor activator of nuclear factor-κB ligand- (RANKL-) primed bone marrow macrophages (BMMs), IL-17 and IFN-γ enhanced osteoclastogenesis, with the expression of osteoclastogenic mRNA (TRAP, c-Fos, MMP-9, Ctsk, and NFATc1) and protein (c-Fos and MMP-9) upregulated. Ligament-induced rat models were established to investigate the role of IL-17 and IFN-γ on experimental periodontitis. Both IL-17 and IFN-γ could enhance the local inflammation in gingival tissues. Although there might be an antagonistic interaction between IL-17 and IFN-γ, IL-17 and IFN-γ could facilitate alveolar bone loss and osteoclast differentiation.

Porphyromonas gingivalis-Induced NLRP3 Inflammasome Activation and Its Downstream Interleukin-1ß Release Depend on Caspase-4.

Background: Oral commensals contribute to microbe-host symbiosis in periodontal homeostasis, and Porphyromonas gingivalis (P. gingivalis) as the keystone pathogen critically accounts for the shift of symbiosis to dysbiosis and periodontal destruction. Nucleotide-binding oligomerization domain (NOD)-like receptor (NLR) family pyrin domain containing 3 (NLRP3) inflammasome-mediated interleukin-1ß (IL-1ß) is significantly involved in periodontal diseases, and notably P. gingivalis enables to modulate the induction and expression of NLRP3. Whereas, the exact mechanism by which NLRP3 inflammasome is regulated in response to commensal and pathogenic bacteria remains unclear. Methods: To examine the expression of IL-1ß and NLRPs inflammasome in tissues with severe chronic periodontitis, and further investigate how Caspase-4-dependent non-canonical NLRP3 inflammasome pathways functioned during the interactions of Streptococcus mitis (S. mitis) and P. gingivalis with human THP-1 cells. Results: IL-1ß and NLRP3, NLRP6, NLRP12, and absent in melanoma 2 (AIM2) inflammasomes are highly expressed in gingival tissues with severe chronic periodontitis. In human THP-1 cells, P. gingivalis activates the synthesis and secretion of IL-1ß to higher levels than S. mitis. Importantly, NLRP3-, Caspase-1-, and Caspase-4-siRNA knockdown THP-1 cells treated with P. gingivalis exhibited a lower expression level of IL-1ß as compared to the control cells. In addition, silencing of either CASP4 or CASP1 can lead to a concurrent or reciprocal decrease in the expression of the other. Of note, the IL-1ß induction is not affected in the S. mitis-treated THP-1 cells with the silence of NLRP3, Caspase-1, and Caspase-4 genes. Conclusion: NLRP3/Caspase-4 and NLRP3/Caspase-1 dependent IL-1ß production may crucially contribute to the dysregulated immuno-inflammatory response in periodontal pathogenesis.

3LPS-binding protein and its interactions with P. gingivalis LPS modulate pro-inflammatory response and Toll-like receptor signaling in human oral keratinocytes.

Lipopolysaccharide (LPS)-binding protein (LBP) as an acute-phase protein plays a crucial role in innate host response to bacterial challenge. Our previous study shows that LBP expression in human gingiva is associated with periodontal status. Porphyromonas gingivalis is a keystone periodontopathogen, and its LPS with lipid A structural heterogeneity critically accounts for periodontal pathogenesis. This study investigated the effects of LBP and its interactions with two featured isoforms of P. gingivalis LPS (tetra-acylated LPS1435/1449 and penta-acylated LPS1690) on the expression of pro-inflammatory cytokines in human oral keratinocytes (HOKs), and the involvement of Toll-like receptor (TLR) signaling. HOKs were pre-incubated with recombinant human LBP (rhLBP) at 10ng/ml, 100ng/ml and 1µg/ml for 1 h, followed by the treatment of P. gingivalis LPS1690 or LPS1435/1449 for 3h or 24h respectively. The expression of IL-6 and IL-8, and involvements of TLR2 and TLR4 were analyzed. The genes associated with TLR signaling were assessed by PCR array. Interestingly, rhLBP per se significantly up-regulated the expression of IL-6 and IL-8 in HOKs (p<0.05), which was blocked by TLR2 antibody (p<0.001). LPS1435/1449 down-regulated more significantly rhLBP-induced IL-6 and IL-8 mRNAs with reference to P. gingivalis LPS1690 (approximately 80% vs. 40%, p<0.05; and 90% vs. 36%, p<0.001, respectively). Moreover, rhLBP markedly down-regulated the gene expression of TLRs and their adaptors such as CD180 (-2.44 folds) and MD-1 (-9.62 folds), while the interaction of P. gingivalis LPS1435/1449 with rhLBP greatly up-regulated both transcripts (7.11 and 4.05 folds, respectively). Notably, P. gingivalis LPS1690-rhLBP interaction dramatically up-regulated CD180 transcript (20.86 folds) and significantly down-regulated MD-1 transcript (-6.93 folds). This pioneering study shows that rhLBP enables to enhance the expression of pro-inflammatory cytokines in HOKs through TLR2 signaling pathway. P. gingivalis LPS with different lipid A structures down-regulates to different extents rhLBP-induced cytokine expression, possibly through fine-tuning of the CD180-MD1 complex and relevant TLRs.

AKT2 is involved in the IL­17A­mediated promotion of differentiation and calcification of murine preosteoblastic MC3T3­E1 cells.

Interleukin (IL)­17A exhibits pleiotropic biological activities and serves a role in the progression of periodontitis. However, data describing the association between IL­17 and osteogenesis are not conclusive. It was previously demonstrated that RAC­ß serine/threonine protein kinase (AKT2)­specific knockdown in MC3T3­E1 cells weakened osteogenic effects. The role of AKT2 in the regulation of IL­17A for osteoblast differentiation and calcification remains unclear. The MTT method was adopted in the present study to assess cell proliferation; cell cycle distribution was analyzed by flow cytometry. Following osteogenic induction treatment, the involvement of phosphatidylinositol 3­kinase (PI3K) and phosphorylated­PI3K was evaluated by western blotting. The effects of IL­17A on osteogenesis­associated markers, including Runt­related transcription factor 2 (Runx­2), alkaline phosphatase (ALP) and osteocalcin (OCN) were evaluated by reverse transcription­quantitative polymerase chain reaction (RT­qPCR) analysis. An ALP activity assay and Alizarin Red S staining were used to assess the differentiation and calcification functions. AKT2 knockdown inhibited MC3T3­E1 cell proliferation, inducing significantly increased G0/G1 cell counts, and reduced S and G2/M cell numbers. IL­17A exerted no significant effects. The protein levels of p­PI3K, gene expression levels of IL­17A, Runx­2, ALP and OCN, and relative ALP activity and calcification areas were increased in the induction group, and these effects were markedly promoted by treatment with IL­17A. AKT2 knockdown in MC3T3­E1 cells resulted in reduced IL­17A­induced differentiation and calcification, although it was not completely inhibited. The results of the present study suggested that AKT2 signaling was required for MC3T3­E1 cell proliferation. IL­17A promoted osteoblast differentiation and calcification in a partly AKT2­dependent manner in MC3T3­E1 cells in vitro, possibly reflecting compensation by other signaling pathways. The results of the present study may offer novel perspectives to guide the clinical strategy for the prevention and treatment of periodontitis.

Porphyromonas gingivalis LPS stimulates the expression of LPS-binding protein in human oral keratinocytes in vitro.

LPS-binding protein (LBP) functions as a crucial molecule in innate immune responses to bacterial challenge. Our study has shown the expression of LBP in human gingiva and its significant association with periodontal health and disease. Porphyromonas gingivalis is a key pathogen of periodontal disease. P. gingivalis LPS as a main virulence factor is strongly involved in periodontal pathogenesis and it displays a significant lipid A structural heterogeneity. Currently, it remains unknown whether, and to what extent, the lipid A structural heterogeneity of P. gingivalis LPS affects LBP expression. The present study investigated the expression profile of LBP in human oral keratinocytes (HOKs) stimulated by two isoforms of P. gingivalis LPS [tetra- (LPS(1435/1449)) and penta-acylated (LPS(1690))] and Escherichia coli LPS, and the involvement of TLRs in LBP expression. The results showed that the expression of LBP mRNA and peptide was significantly up-regulated by P. gingivalis LPS(1690) and E. coli LPS, while P. gingivalis LPS(1435/1449) did not affect LBP expression. Blocking assay and siRNA gene silencing revealed that P. gingivalis LPS(1690)-induced LBP expression was through both TLR2 and TLR4. This in vitro study demonstrates that P. gingivalis LPS with a lipid A structural heterogeneity differentially modulates LBP expression in HOKs.

Osteogenic effect of Drynariae rhizoma extracts and Naringin on MC3T3-E1 cells and an induced rat alveolar bone resorption model.

OBJECTIVE: To investigate if Drynariae rhizoma (DR) and its main ingredient Naringin could reduce alveolar bone loss by stimulating the proliferation and differentiation of osteoblasts. MATERIALS AND METHODS: The effect of DR water (DRWE), ethanolic extract (DREE), and Naringin on MC3T3-E1 cells was evaluated respectively by MTT method and by measuring the activity of alkaline phosphatase (ALP activity) as well as the level of osteocalcin in medium. Bone mineral density (BMD) detection, osteoclast counting by tartrate resistant acid phosphatase staining, and histopathological analysis were performed in an induced rat model of alveolar bone resorption after gastric perfusion with DR extracts or Naringin. RESULTS: DRWE and Naringin effectively increased the proliferation of MC3T3-E1 cells, whilst DREE and Naringin enhanced the differentiation of osteoblastic cells. The in vivo study indicated an elevated BMD value in the tooth-periodontal tissues from DRWE, DREE and Naringin treated groups after 10, 20 and 30 days of perfusion (P<0.05). In DRWE treated group, the number of osteoclasts at days 10, 20 and 30 decreased remarkably as compared to the corresponding negative controls (P<0.05), and no osteoclast could be found at day 30. New non-calcified bone-like matrix attached by osteoblasts at the root furcation was also shown. CONCLUSIONS: DR could be a supplementary medicine for periodontal therapy as it could reduce bone resorption in rat model of alveolar bone resorption and exert osteogenic effect on osteoblasts.