Role of IL-6 and STAT3 signaling in dihydropyridine-induced gingival overgrowth fibroblasts.

OBJECTIVES: This study analyzed the role of the interleukin (IL)-6/signal transducer and activator of transcription 3 (STAT3) pathway in dihydropyridine-induced gingival overgrowth (DIGO) fibroblasts. MATERIALS AND METHODS: Tissue samples were obtained through surgical dissection from five DIGO patients and five healthy individuals. Cell cultures were conditioned with nifedipine (Nif) (0.34 µM) and stimulated with IL-1ß (10 ng/ml) to clarify whether IL-6 upregulates extracellular matrix overproduction or has an impact on the cell proliferation rate of DIGO fibroblasts. STAT3 was knocked down using short hairpin (sh)RNA to determine its role in collagen (Col) type I alpha 1 (Colα1(I)) synthesis. RESULTS: Results showed that phosphorylated (p)STAT3 nuclear translocation was activated by a simulated autocrine concentration (50 ng/ml) of IL-6, and application of an anti-IL-6 antibody significantly decreased the pSTAT3/STAT3 ratio in DIGO fibroblasts. STAT3 knockdown significantly decreased STAT3 and Colα1(I) expressions in DIGO cells. DIGO tissues presented stronger proliferating cell nuclear antigen (PCNA) expression than did healthy individuals under the effect of IL-1ß/Nif treatment. CONCLUSIONS: Gingival inflammation (e.g., IL-1ß) and taking dihydropyridine (e.g., Nif) may additively stimulate Col overproduction through the IL-6-STAT3-Colα1(I) cascade in DIGO cells. IL-6-STAT3 signaling may be considered a target for the control of DIGO.

Dental education changed by COVID-19: Student's perceptions and attitudes.

BACKGROUND: Dental students have encountered changes in the teaching format amid the SARS CoV-2 pandemic. This study aims to evaluate the attitudes of dental students of one medical university toward online courses and compare them with those of non-dental students amid the SARS CoV-2 pandemic. METHODS: A cross-sectional survey with a self-report online questionnaire was conducted at the medical university in May 2020 in Taipei. Students from the School of Dentistry, School of Dental Technology, and School of Oral Hygiene Study were enrolled in our survey. RESULTS: In total, 473 students responded to the survey, 318 (67.2%) of whom were dental students. Overall, 366 (77%) students agreed with the change to online learning. Only 10.4% of students thought that dental professional courses with a laboratory format could be changed to online courses. Dental students were significantly more worried than non-dental students about being infected with COVID-19 and about the COVID-19 pandemic continuing. CONCLUSIONS: In conclusion, changing to online learning seems to be perceived as feasible by students. However, more discussion about changing dental professional courses with a laboratory format to online courses considering the attitudes from students is needed.

Therapeutic potential of proteasome inhibitors for dihydropyridine-induced gingival overgrowth.

OBJECTIVES: NF-κB plays a crucial role in collagen overproduction in dihydropyridine-induced gingival overgrowth (DIGO) fibroblasts. We aim to investigate the role of the kappa B (IκB) kinase (IKK)-NF-κB pathway and downstream collagen type I (Col I) synthesis in DIGO cells and to demonstrate the therapeutic strategy of interference of this pathway with proteasome inhibitors. METHODS: Gingival fibroblasts from DIGO (n = 5) and healthy (n = 5) patients were selected and stimulated with IL-1ß, nifedipine, or both. All experiments were run in triplicate and independently for each primary cell sample. RESULTS: The results demonstrated that both drugs additively mediated NF-κB activity by activating IKKα/ß phosphorylation. They also triggered nuclear translocation of NF-κB, Rela, and p50 (*p < .05) and increased Col I production in both healthy and DIGO cells. The addition of proteasome inhibitors, including bortezomib and MG132, promoted the accumulation of phosphorylated p-IκBα, prevented the subsequent cytosol-to-nuclear translocation of p50 and Rela (*p < .05), and abbreviated the biosynthesis of Col I in DIGO cells. CONCLUSIONS: We suggested that IKK-IκBα activation is mediated by proinflammatory cytokines and CCBs in DIGO cells and triggers downstream NF-κB-Col I synthesis. Proteasome inhibitors may strategically interfere with the IKK-IκBα-NF-κB-Col I pathway and inhibit the etiopathogenesis of DIGO.

Evidence-based clinical decision making for the management of patients with periodontal osseous defect after impacted third molar extraction: A systematic review and meta-analysis.

BACKGROUND/PURPOSE: Extraction of impacted mandibular third molar (MTM) is one of the most common procedures in clinical dental treatment; building a decision tree to perform MTM extraction can be prudent in alleviating periodontal diseases. This study is to review the latest research on the management of periodontal osseous defect (POD) after MTM extraction and rebuild a new clinical decision tree. MATERIALS AND METHODS: Current study was conducted according to PRISMA statement. Medline, Embase, Scopus, and Google Scholar were searched concerning treatment of MTM extraction up to Oct.2019. Three focused questions revolving around asymptomatic versus disease site, age, and necessity of ridge preservation after >6 months follow up will be answered. RESULTS: A total of 7 studies were included for meta-analysis. Evidences were inadequate in regards to asymptomatic vs disease site of MTM extraction in the long-term follow-up. For patients with age <25 years, postoperative probing depth (PD) always remained at < 4 mm. However, for patients with age >25 years with initial PD > 7 mm, residual pockets still remained at 5 mm. For ridge preservation, significant positive effect in reduction of second molar distal site PD was observed, regardless of different biomaterials being placed (z = 4.69, p < 0.00001). CONCLUSION: Age is of utmost importance in preoperative evaluation during impacted MTM extraction. The timing for ridge preservation is essential determinant for achieving optimal treatment outcome. The clinical decision tree as proposed could serve as guidance when dealing with POD after impacted MTM extraction.

The Association between Bone Mineral Density and Periodontal Disease in Middle-Aged Adults.

The association between osteoporosis and periodontal disease (PD) has been revealed by previous studies, but there have been few studies on the association in younger adults. We enrolled a total of 7298 adults aged 40 to 44 who underwent PD screening between 2003 and 2008. Data on quantitative ultrasound for the measurement of bone mineral density (BMD) were collected for the diagnostic criteria of osteopenia and osteoporosis. The Community Periodontal Index (CPI) was measured for defining PD. A multiple logistic regression model was used to assess the effect of low bone mass on the risk of PD. Of 7298 enrollees, 31% had periodontal pockets >3 mm, 36.2% had osteopenia, and 2.1% had osteoporosis. The 39.8% of PD prevalence was high in adults with osteoporosis, followed by 33.3% in osteopenia. A negative association was found between BMD and CPI value (p < 0.0001). Low bone mass was associated with the risk of PD (adjusted OR: 1.13; 95% CI:1.02-1.26) after adjusting the confounding factors, including age, gender, education level, overweight, smoking status, past history of osteoporosis, and diabetes mellitus. An association between BMD and PD among young adults was found. An intervention program for the prevention of PD and osteoporosis could be considered starting in young adults.

Quantitative analysis of Miller mobility index for the diagnosis of moderate to severe periodontitis - A cross-sectional study.

BACKGROUND/PURPOSE: We assessed the mobility of single-root teeth by using Miller's mobility index (MMI) and to analyze the validity of MMI for the diagnosis of periodontitis. MATERIALS AND METHODS: A total of 30 patients were included and the Spearman correlation coefficient was used to assess the correlation between MMI, clinical attachment level (CAL), and probing depth (PD). The validity of MMI for the diagnosis of the severity of periodontitis was evaluated using the receiver operating characteristic (ROC) curve, area under curve (AUC) value, positive predictive value (PPV). RESULTS: Strong correlations were observed between MMI and CAL (r = 0.92) and between MMI and PD (r = 0.76). When the CAL = 3-4 mm and CAL ≥5 mm groups were pooled together, the AUC value was 0.81. The AUC was 0.86 for diagnosis with MMI in the CAL ≥5 mm group. A PPV of 100% was achieved for all grades when MMI >1. When the teeth with PD ≥ 5 to <7 mm and PD ≥ 7 mm groups were pooled together, the AUC value for MMI was 0.80. The PPV was 98.8%, 99%, and 100% for MMI Grade 1, Grade 2, and Grade 3, respectively. When PD ≥ 7 mm was defined as severe periodontitis, the AUC value for MMI was 0.72. CONCLUSION: MMI may provide valuable information for the diagnosis of moderate and severe periodontitis when CAL is not obtainable during routine practice.