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About Du T, Wang Z, Shen Y, Ma J, Cao Y, Haapasalo M.

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So far Du T, Wang Z, Shen Y, Ma J, Cao Y, Haapasalo M. has created 996 blog entries.

Combined antibacterial effect of sodium hypochlorite and root canal sealers against Enterococcus faecalis biofilms in dentin canal

INTRODUCTION:

The present study aimed to evaluate the antibacterial effect of the combined use of sodium hypochlorite (NaOCl) and root canal sealers on Enterococcus faecalis biofilms using a dentin infection model.

METHODS:

Cells of E. faecalis were introduced into the dentinal tubules by centrifugation and incubated in brain-heart infusion for 3 weeks. The biofilms in dentin were first subjected to 5% NaOCl or sterile water for 10 minutes followed by an equal thickness of AH Plus (Dentsply International Inc, York, PA), Endosequence BC Sealer (Brasseler USA, Savannah, GA), or MTA Fillapex (Angelus Indústria de Produtos Odontológicos S/A, Londrina, Brazil) placed on the root canal wall of the dentin specimens for 7, 30, and 60 days. Gutta-percha and water were used in a similar manner as controls. The proportions of dead and live bacteria inside the dentinal tubules were assessed by confocal laser scanning microscopy and viability staining.

RESULTS:

The combined use of NaOCl and sealers (30 and 60 days) killed significantly more bacteria than NaOCl or sealers alone (P < .05). NaOCl + MTA Fillapex was the most effective antibacterial combination by killing 83% bacteria in dentin tubules in 60 days. Thirty and 60 days of exposure to the sealers resulted in significantly more dead bacteria in dentin biofilms than 7-day exposures (P < .05).

CONCLUSIONS:

The placement of root canal sealer after NaOCl treatment enhanced antibacterial effects against E. faecalis in the dentinal tubules. Little additional effect was obtained after 30 days of exposure to sealers.

By |2019-05-24T20:26:07+00:00January 1st, 2015|Other|

Oral infections, metabolic inflammation, genetics, and cardiometabolic diseases.

Although several epidemiologic studies reported plausible and potentially causal associations between oral infections and cardiometabolic diseases (CMDs), controversy still lingers. This might be due to unrecognized confounding from metabolic inflammation and genetics, both of which alter the immune responses of the host. Low-grade inflammation termed metainflammation is the hallmark of obesity, insulin resistance, type 2 diabetes, and CMDs. According to the common soil theory, the continuum of obesity to CMDs is the same pathology at different time points, and early metainflammations, such as hyperglycemia and obesity, display many adverse cardiometabolic characteristics. Consequently, adipose tissue is now considered a dynamic endocrine organ that expresses many proinflammatory cytokines such as TNF-α, IL-6, plasminogen activator inhibitor 1, and IL-1β. In metainflammation, IL-1β and reactive oxygen species are generated, and IL-1β is a pivotal molecule in the pathogenesis of CMDs. Note that the same cytokines expressed in metainflammation are also reported in oral infections. In metabolic inflammation and oral infections, the innate immune system is activated through pattern recognition receptors-which include transmembrane receptors such as toll-like receptors (TLRs), cytosolic receptors such as nucleotide-binding oligomerization domain-like receptors, and multiprotein complexes called inflammasome. In general, TLR-2s are presumed to recognize lipoteichoic acid of Gram-positive microbes-and TLR-4s, lipopolysaccharide of Gram-negative microbes-while nucleotide-binding oligomerization domain-like receptors detect both Gram-positive and Gram-negative peptidoglycans on the bacterial cell walls. However, a high-fat diet activates TLR-2s, and obesity activates TLR-4s and induces spontaneous increases in serum lipopolysaccharide levels (metabolic endotoxemia). Moreover, genetics controls lipid-related transcriptome and the differentiation of monocyte and macrophages. Additionally, genetics influences CMDs, and this creates a confounding relationship among oral infections, metainflammation, and genetics. Therefore, future studies must elucidate whether oral infections can increase the risk of CMDs independent of the aforementioned confounding factors.

Allergy and autoimmunity caused by metals: a unifying concept.

This chapter will give an overview of the literature on metal-induced pathologies, such as delayed-type hypersensitivity and autoimmunity. Because of the vast amount of information avail-able on this subject, the focus of this review will be mainly on specific T cell reactivity to mercury, aluminum, nickel, and gold, all of which are known to induce immunotoxic effects in human subjects. Mercury, as a constituent of thimerosal, and aluminum are both used in vaccines.

By |2018-07-31T20:02:07+00:00January 1st, 2015|Mercury, Other|

A comparative evaluation of the amount of fluoride release and re-release after recharging from aesthetic restorative materials: an in vitro study.

AIM:
To measure the amount of fluoride released and re released after recharging from various restorative materials: Conventional Glass Ionomer Cement (Fuji II), Light Cure Resin Modified GIC (Fuji II LC), Giomer (Beautifil II), Compomer (Dyract).

MATERIALS AND METHODS:
Fifteen cylindrical specimens were prepared from each material. The specimens were immersed in 20 ml of deionized water. The amount of released fluoride was measured during the 1(st) day, 7(th) day and on the day15 by using specific fluoride electrode and an ion-analyser. After 15 days each material was divided into three Sub Groups of five samples each. Sub Group A served as control, Sub Group B was exposed to 2% NaF solution, Sub Group C to 1000ppm F toothpaste. The amount of fluoride re-released was measured during the 1(st) day, 7(th) day and on the day15 by using specific fluoride electrode and an ion-analyser. The results were statistically analysed using analysis of variance (one-way ANOVA) and Tukey Kramer multiple comparison tests (p≤0.05).

RESULTS:
Independent of the observation time period of the study the Conventional GIC released the highest amount of fluoride followed by RMGIC, Giomer and Compomer. The initial burst effect was seen with GIC’S but not with Giomer and Compomer. After topical fluoride application fluoride re release was highest in Sub Group B and GIC had a greater recharging ability followed by RMGIC, Giomer and Compomer. The fluoride re release was greatest on 1(st) day followed by rapid return to near exposure levels.

CONCLUSION:
From the study it was concluded that, the initial Fluoride release was highest from Conventional GIC followed by Resin Modified GIC, Giomer and Compomer. The Fluoride re release was high when recharging with professional regime (2% NaF) as compared to home regime (Toothpaste). Conventional GIC had a greater recharging ability followed by Resin Modified GIC, Giomer and Compomer.

By |2018-07-18T19:37:34+00:00January 1st, 2015|Fluoride|

A critique of recent economic evaluations of community water fluoridation.

BACKGROUND:

Although community water fluoridation (CWF) results in a range of potential contaminant exposures, little attention has been given to many of the possible impacts. A central argument for CWF is its cost-effectiveness. The U.S. Government states that $1 spent on CWF saves $38 in dental treatment costs.

OBJECTIVE:

To examine the reported cost-effectiveness of CWF.

METHODS:

Methods and underlying data from the primary U.S. economic evaluation of CWF are analyzed and corrected calculations are described. Other recent economic evaluations are also examined.

RESULTS:

Recent economic evaluations of CWF contain defective estimations of both costs and benefits. Incorrect handling of dental treatment costs and flawed estimates of effectiveness lead to overestimated benefits. The real-world costs to water treatment plants and communities are not reflected.

CONCLUSIONS:

Minimal correction reduced the savings to $3 per person per year (PPPY) for a best-case scenario, but this savings is eliminated by the estimated cost of treating dental fluorosis.

By |2018-08-27T20:03:31+00:00January 1st, 2015|Fluoride|

Patch testing in oral lichenoid lesions of uncertain etiology.

BACKGROUND:
The benefit of patch testing patients with oral lichenoid lesions (OLL) is still debated.

OBJECTIVE:
We assessed the results of patch testing in patients with multiple amalgams and multiple OLL, where the etiology of the oral mucosal disease was unclear.

METHODS:
Patients referred from an oral medicine clinic were patch tested to the British Society of Cutaneous Allergy standard series, dental and materials series, and, in 1 patient, the dental methacrylate series also. Patients’ responses to amalgam removal were assessed during a mean follow-up of 2.6 (range, 0-4.75) years.

RESULTS:
Thirty-one patients with OLL were referred for patch testing. Ten (32%) patients tested positively to mercury. Eight patients with positive reactions to mercury had amalgam removal, with complete or partial resolution of the OLL in all cases (100%).

CONCLUSIONS:
Patients with OLL of unclear etiology adjacent to large amalgam restorations should be investigated for delayed contact hypersensitivity. Removal of amalgams in patients with positive patch test reactions to mercury results in improvement or resolution of the OLL in most patients.

Increased mercury release from dental amalgam restorations after exposure to electromagnetic fields as a potential hazard for hypersensitive people and pregnant women.

Over the past decades, the use of common sources of electromagnetic fields such as Wi-Fi routers and mobile phones has been increased enormously all over the world. There is ongoing concern that exposure to electromagnetic fields can lead to adverse health effects. It has recently been shown that even low doses of mercury are capable of causing toxicity. Therefore, efforts are initiated to phase down or eliminate the use of mercury amalgam in dental restorations. Increased release of mercury from dental amalgam restorations after exposure to electromagnetic fields such as those generated by MRI and mobile phones has been reported by our team and other researchers. We have recently shown that some of the papers which reported no increased release of mercury after MRI, may have some methodological errors. Although it was previously believed that the amount of mercury released from dental amalgam cannot be hazardous, new findings indicate that mercury, even at low doses, may cause toxicity. Based on recent epidemiological findings, it can be claimed that the safety of mercury released from dental amalgam fillings is questionable. Therefore, as some individuals tend to be hypersensitive to the toxic effects of mercury, regulatory authorities should re-assess the safety of exposure to electromagnetic fields in individuals with amalgam restorations. On the other hand, we have reported that increased mercury release after exposure to electromagnetic fields may be risky for the pregnant women. It is worth mentioning that as a strong positive correlation between maternal and cord blood mercury levels has been found in some studies, our findings regarding the effect of exposure to electromagnetic fields on the release of mercury from dental amalgam fillings lead us to this conclusion that pregnant women with dental amalgam fillings should limit their exposure to electromagnetic fields to prevent toxic effects of mercury in their fetuses. Based on these findings, as infants and children are more vulnerable to mercury exposures, and as some individuals are routinely exposed to different sources of electromagnetic fields, we possibly need a paradigm shift in evaluating the health effects of amalgam fillings.

By |2019-06-21T20:40:54+00:00January 1st, 2015|Mercury|

Mouthwashes and their use in different oral conditions.

Mouthwashes are medicated solutions used for gargling and rinsing the mouth. Many oral conditions require the use of a mouthwash, which can vary from oral malodour to periodontal disease to treatment of secondary infections like oral mucositis. A mouthwash may be recommended as an antimicrobial, a topical anti-inflammatory agent, a topical analgesic or for caries prevention. Many different mouthwashes are available now a day. Selection of an appropriate mouthwash depends on patient’s oral condition, disease risk and efficiency and safety of mouthwash. The main objective of this review is to help the oral health care professionals to make the correct selection of mouthwash while dealing with different conditions of oral cavity.

By |2018-07-27T18:44:52+00:00January 1st, 2015|Fluoride|
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