Effect of epigallocatechin-3-gallate on tumor necrosis factor-alpha production by human gingival fibroblasts stimulated with bacterial lipopolysaccharide: An in vitro study.

BACKGROUND: Evidence shows that epigallocatechin-3-gallate (EGCG) in green tea has anti-inflammatory effects. AIM: This study assessed the effect of EGCG on the production of tumor necrosis factor-alpha (TNF-α) as an inflammatory cytokine in periodontitis, which produced by human gingival fibroblasts (HGFs) stimulated with lipopolysaccharide (LPS) of Porphyromonas gingivalis. MATERIALS AND METHODS: In this study, HGFs were cultured and subjected to LPS and EGCG. Cell viability of different concentrations of EGCG (10, 25, 50, 75, and 100 µM) and LPS (1, 10, 20, and 50 µg/mL) was assessed using methyl-thiazole-tetrazolium (MTT) assay. Then, the best concentrations of EGCG and P. gingivalis LPS were used simultaneously and separately to assess the production of TNF-α by HGFs using the enzyme-linked immunosorbent assay (ELISA). Assessments were done at 1, 3, and 5 days. Data were read using the ELISA reader and analyzed by the SPSS through two-way ANOVA. RESULTS: LPS at 1, 10, and 20 and EGCG at 10.25 and 50 µM showed the least cytotoxicity in MTT assay. ELISA showed EGCG alone decreased the production of TNF-α in all days, except 10 µM on day 1. 1, 10, and 20 µg/mL LPS increased the output of TNF-α on days 1 and 3 while reducing it on day 5. The combination of EGCG and LPS showed a decrease of TNF-α in all days except on day 5 that revealed an increase in the production of TNF-α at 25 and 50 µM EGCG. CONCLUSION: In the combination use of EGCG and LPS, EGCG shows anti-inflammatory effects by decreasing the production of TNF-α by HGFs stimulated with P. gingivalis.

Comparative evaluation of the cortisol level of unstimulated saliva in patients with and without chronic periodontitis.

BACKGROUND: Chronic periodontitis (CP) is one of the most prevalent diseases of the oral cavity with various biological and behavioral risk factors. We aimed to evaluate the association between the salivary cortisol level (SCL) of unstimulated saliva and CP in patients referred to Isfahan Dental Faculty. MATERIALS AND METHODS: In this analytic cross-sectional study, 90 patients were selected based on the presence of periodontitis and were divided into two groups: with periodontitis and without periodontitis (n = 45). First, by evaluating the level of anxiety with Spielberger State-Trait Anxiety Inventory questionnaire, each group was divided into three subgroups, each containing 15 persons. To measure the SCL in all subgroups by the enzyme-linked immunosorbent assay method, saliva samples were collected with unstimulated spitting method between 9 and 11 AM. Periodontal evaluation was done using the mean probing depth (PD), plaque index, and bleeding on probing. The obtained data were analyzed using SPSS software (version 20, IBM Corp., Armonk, N.Y., USA) and analysis of variance, independent t-test, Chi-square, Mann-Whitney, Spearman correlation, and Pearson correlation coefficient tests (α = 0.05). RESULTS: The mean level of salivary cortisol (P = 0.048) and PD (P = 0.009) in patients with periodontitis was significantly higher than those without periodontitis. There was a direct and meaningful correlation between PD and SCL (P < 0.001, r = 0.363). In both groups of participants with (P < 0.001) and without periodontitis (P < 0.001), the mean SCL in patients with high anxiety was significantly more than patients with medium and low anxiety. CONCLUSION: Our results showed that there is an increased level of salivary cortisol (as anxiety index) in patients with CP. Therefore, it seems that the probability of the occurrence of periodontitis is higher in those with increased cortisol level.

Comparison of Er:YAG Laser and Hand Instrumentation on the Attachment of Cultured Human Gingival Fibroblasts to Periodontally Involved Root Surfaces.

Introduction: The present study compared the effects of erbium-doped yttrium aluminium garnet (Er:YAG) laser and hand instrumentation on the attachment of human gingival fibroblast (HGF) cells to periodontally involved root surfaces. Methods: A total of 40 tooth specimens were collected and treated in four distinct groups: scaled and root planed with hand instruments, scaled with Er:YAG laser, treated with a combination of hand instruments and Er:YAG laser and non-treated control group. The attachment and proliferation rate of HGF were assessed using MTT assay and scanning electron microscope (SEM) examination was used for cell morphological evaluation. Results: The MTT (3-[4, 5-dimethylthiazol-2-yl]-2, 5 diphenyl tetrazolium bromide) assay showed significant decrease in HGF cell viability in both hand instruments only and combination treated teeth specimens compared to control specimens (P<0.05), 24 hours after cell seeding. However, at time 48, the cell viability of attached cells in these 2 treated groups was almost similar to control. In contrast, at 24 and 48 hours after cell seeding, viability of attached cells was higher than control in Er:YAG laser treated only specimens (P<0.05). According to SEM study, the laser treated specimens showed more surface roughness. Conclusion: Er:YAG laser increased attachment and proliferation of HGF cells in comparison to the hand instruments method.

Short dental implants in the posterior maxilla: a review of the literature.

The purpose of this study was to perform a literature review of short implants in the posterior maxilla and to assess the influence of different factors on implant success rate. A comprehensive search was conducted to retrieve articles published from 2004 to 2015 using short dental implants with lengths less than 10 mm in the posterior maxilla with at least one year of follow-up. Twenty-four of 253 papers were selected, reviewed, and produced the following results. (1) The initial survival rate of short implants in the posterior maxilla was not related to implant width, surface, or design; however, the cumulative success rate of rough-surface short implants was higher than that of machined-surface implants especially in performance of edentulous dental implants of length <7 mm. (2) While bone augmentation can be used for rehabilitation of the atrophic posterior maxilla, short dental implants may be an alternative approach with fewer biological complications. (3) The increased crown-to-implant (C/I) ratio and occlusal table (OT) values in short dental implants with favorable occlusal loading do not seem to cause peri-implant bone loss. Higher C/I ratio does not produce any negative influence on implant success. (4) Some approaches that decrease the stress in posterior short implants use an implant designed to increase bone-implant contact surface area, providing the patient with a mutually protected or canine guidance occlusion and splinting implants together with no cantilever load. The survival rate of short implants in the posterior edentulous maxilla is high, and applying short implants under strict clinical protocols seems to be a safe and predictable technique.

In Vitro Study of Er:YAG and Er, Cr:YSGG Laser Irradiation on Human Gingival Fibroblast Cell Line.

The ultimate goal of the periodontal treatments is a regeneration of periodontium. Recently, laser irradiations are commonly used to improve wound repair. Because of many controversies about the effects of laser on soft tissue regeneration, more in vitro studies are still needed. The aim of the present in vitro study was to compare the effects of different doses of Er:YAG (erbium-doped:yttrium, aluminum, garnet) and Er, Cr:YSGG (erbium, chromium-doped: yttrium, scandium, gallium, garnet) laser treatment on human gingival fibroblasts (HGF) proliferation. In this randomized single-blind controlled in vitro trial, HGF cells were irradiated using Er:YAG and Er, Cr:YSGG laser for 10 and 30 seconds or remained unexposed as a control group. After a culture period of 24 and 48 hours, HGF cell proliferation was evaluated by MTT assay. The data were subjected to one-sided analysis of variance and Tukey multiple comparison tests. Our results showed Er:YAG application for 10 and 30 seconds as well as Er, Cr:YSGG irradiation for 10 and 30 seconds induced statistically significant (P<0.05) proliferation of HGF cells as compared with the control at 24 hours up to 18.39%, 26.22%, 21.21%, and 17.06% respectively. In 48 hour incubations, Er:YAG and Er, Cr:YSGG irradiation for 10 and 30 seconds significantly increased cellular proliferation up to 22.9%, 32.24%, 30.52% and 30.02% respectively (P<0.05). This study demonstrates that Er:YAG and Er, Cr:YSGG laser significantly increased HGF cell proliferation compared to the control specimens. This higher proliferation can lead to increased wound repair in clinical conditions.

Effects of nicotine in the presence and absence of vitamin E on morphology, viability and osteogenic gene expression in MG-63 osteoblast-like cells.

BACKGROUND: Evidence shows that oxidative stress induced by nicotine plays an important role in bone loss. Vitamin E with its antioxidative properties may be able to reverse the effects of nicotine on bone. This study aimed to assess the effects of nicotine in the presence and absence of vitamin E on morphology, viability and osteogenic gene expression in MG-63 (osteosarcoma) human osteoblast-like cells. METHODS: We treated the cells with 5 mM nicotine. The viability and morphology of cells were evaluated respectively using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium (MTT) and crystal violet assays. The effect of nicotine on osteogenic gene expression in MG-63 cells was assessed by real-time reverse-transcription polymerase chain reaction of osteoblast markers, namely, alkaline phosphatase, osteocalcin and bone sialoprotein. RESULTS: The results revealed that survival and proliferation of MG-63 cells were suppressed following exposure to nicotine, and cytoplasm vacuolization occurred in the cells. Nicotine significantly down-regulated the expression of osteogenic marker genes. Such adverse effects on morphology, viability and osteogenic gene expression of MG-63 cells were reversed by vitamin E therapy. CONCLUSIONS: In conclusion, vitamin E supplementation may play a role in proliferation and differentiation of osteoblasts, and vitamin E can be considered as an anabolic agent to treat nicotine-induced bone loss.

Solubility of Two Root-End Filling Materials over Different Time Periods in Synthetic Tissue Fluid: a Comparative Study.

STATEMENT OF THE PROBLEM: Insolubility is an important criterion for an ideal root-end filling material to both prevent any microleakage between the root canal and the periradicular space and provide sealing ability. PURPOSE: Many recent studies have shown that mineral trioxide aggregate (MTA) and calcium-enriched mixture (CEM) have acceptable sealing ability. The purpose of this in vitro study was to evaluate the solubility of these root-end filling materials. MATERIALS AND METHOD: Forty stainless steel ring moulds with an internal diameter of 10±1 mm and a height of 2±0.1 mm were selected. Samples of MTA and CEM were mixed according to the manufacturer's instructions and inserted into the moulds. The specimens were divided into 4 experimental groups and kept in synthetic tissue fluid (STF) for 2 different time periods (7 and 28 days). The control group contained 8 empty rings. The moulds' weights were recorded before and after immersion in STF. The changes in the weight of the samples were measured and compared using a two- way ANOVA test at a significance level of 5%. Specimens were evaluated with scanning electron microscopy (SEM) at a magnification of 500×. RESULTS: There was no significant difference in weight changes between MTA and CEM samples (p> 0.05). CONCLUSION: MTA and CEM have similar solubility in STF in different time periods.