Adriana Fernandes da Silva

Bond strength of universal adhesives: A systematic review and meta-analysis.

OBJECTIVES A systematic review was conducted to determine whether the etch-and-rinse or self-etching mode is the best protocol for dentin and enamel adhesion by universal adhesives. DATA This report followed the PRISMA Statement. A total of 10 articles were included in the meta-analysis. SOURCES Two reviewers performed a literature search up to October 2014 in eight databases: PubMed, Web of Science, Scopus, BBO, SciELO, LILACS, IBECS and The Cochrane Library. STUDY SELECTION In vitro studies evaluating the bond strength of universal adhesives to dentin and/or enamel by the etch-and-rinse and self-etch strategies were eligible to be selected. Statistical analyses were conducted using RevMan 5.1 (The Cochrane Collaboration, Copenhagen, Denmark). A global comparison was performed with random-effects models at a significance level of p<0.05. RESULTS The analysis of dentin micro-tensile bond strength showed no statistically significant difference between the etch-and-rinse and self-etch strategies for mild universal adhesives (p≥0.05). However, for the ultra-mild All-Bond Universal adhesive, the etch-and-rinse strategy was significantly different than the self-etch mode in terms of dentin micro-tensile bond strength, as well as in the global analysis of enamel micro-tensile and micro-shear bond strength (p≤0.05). CONCLUSIONS The enamel bond strength of universal adhesives is improved with prior phosphoric acid etching. However, this effect was not evident for dentin with the use of mild universal adhesives with the etch-and-rinse strategy. CLINICAL SIGNIFICANCE Selective enamel etching prior to the application of a mild universal adhesive is an advisable strategy for optimizing bonding.

A systematic review about antibacterial monomers used in dental adhesive systems: Current status and further prospects.

OBJECTIVES This study systematically review the literature to assess the effectiveness of antibacterial monomers incorporated into dental adhesive systems against major oral bacteria; as well as the research advances and the future prospects of this technology. METHODS The following seven databases were screened: MedLine (PubMed), Lilacs, Ibecs, Web of Science, Scopus, Scielo, and The Cochrane Library. Furthermore, the online system Questel Orbit (Paris, France) was accessed to obtain patent data. The inclusion criteria were articles and patents that investigated the antimicrobial activity of antibacterial monomers in dental adhesive systems. Only documents written in English, Spanish or Portuguese were included. RESULTS After screening, 33 studies and eight patents fulfilled all the criteria and were included. Antibacterial agents, such as QA, MDPB, DMAHM and DMADDM were found in patents, which claimed their incorporation into adhesive compositions, dental cements, composite resins. MDPB was the only antimicrobial monomer incorporated into a commercially available adhesive system, Clearfil Protect Bond™ (Kuraray Co. Ltd., Japan). All studies reported the inclusion of antimicrobial monomers in adhesive systems to be an effective dental treatment strategy. SIGNIFICANCE There are potential areas to be explored with antibacterial monomers for dentistry, and their use could have important implications for future more conservative dental treatments. Although there is evidence of antibacterial activity from in vitro studies, clinical studies must be conducted to confirm the effectiveness of these materials in the prevention of dental pathologies.

Functionalized Scaffolds to Control Dental Pulp Stem Cell Fate

Emerging understanding about interactions between stem cells, scaffolds, and morphogenic factors has accelerated translational research in the field of dental pulp tissue engineering. Dental pulp stem cells constitute a subpopulation of cells endowed with self-renewal and multipotency. Dental pulp stem cells seeded in biodegradable scaffolds and exposed to dentin-derived morphogenic factors give rise to a pulplike tissue capable of generating new dentin. Notably, dentin-derived proteins are sufficient to induce dental pulp stem cell differentiation into odontoblasts. Ongoing work is focused on developing ways of mobilizing dentin-derived proteins and disinfecting the root canal of necrotic teeth without compromising the morphogenic potential of these signaling molecules. On the other hand, dentin by itself does not appear to be capable of inducing endothelial differentiation of dental pulp stem cells despite the well-known presence of angiogenic factors in dentin. This is particularly relevant in the context of dental pulp tissue engineering in full root canals in which access to blood supply is limited to the apical foramina. To address this challenge, scientists are looking at ways to use the scaffold as a controlled-release device for angiogenic factors. The aim of this article was to present and discuss current strategies to functionalize injectable scaffolds and customize them for dental pulp tissue engineering. The long-term goal of this work is to develop stem cell-based therapies that enable the engineering of functional dental pulps capable of generating new tubular dentin in humans.

2-Hydroxyethyl methacrylate as an inhibitor of matrix metalloproteinase-2

This study evaluated the effect of different concentrations of 2-hydroxyethyl methacrylate (HEMA) on the inhibition of matrix metalloproteinase-2 (MMP-2) in vitro. Mouse gingival explants were cultured overnight in Dulbeccos modified Eagles minimal essential medium, following which the expression of secreted enzymes was analyzed by gelatin zymography and the effects of different amounts of HEMA on enzyme activity were investigated. The gelatinolytic proteinases present in the conditioned media were characterized as being matrix metalloproteinases (MMPs) by means of specific chemical inhibition. The MMPs present in the conditioned media were identified, using immunoprecipitation, as MMP-2. Three major bands were detected in the zymographic assays and were characterized, according to their respective molecular weights, into the following forms of MMP-2: zymogene (72 kDa), intermediate (66 kDa), and active (62 kDa). All forms of MMP-2 were inhibited by HEMA in a dose-dependent manner, implying that MMP-2 may be inhibited by HEMA in vivo.

Histologic response and tenascin and fibronectin expression after pulp capping in pig primary teeth with mineral trioxide aggregate or calcium hydroxide.

This study evaluated the histological response and the expression of tenascin (TN) and fibronectin (FN) after pulp capping with mineral trioxide aggregate (MTA) or calcium hydroxide (CH). Class V cavities and pulp exposure were performed in 40 primary pig teeth. The pulps were capped with either MTA or CH, and the cavities were sealed with resin-modified glass ionomer cement. CH was used as a control. Seven and 70 days posttreatment, the animals were sacrificed and teeth were prepared for histological evaluation. TN and FN were detected by immunostaining. A severe inflammatory response was observed after 7 days in the CH group (p<0.043), while in the MTA group, a mild response was observed. Similar reparative dentin deposition was observed after 70 days for both groups (p<0.005). The expression of FN and TN was similar for both groups in the two periods evaluated. TN and FN were expressed during pulp reparative events, independently of the capping material.

Endocrown restorations: A systematic review and meta-analysis

OBJECTIVES A systematic review was conducted to evaluate clinical (survival) and in vitro (fracture strength) studies of endocrown restorations compared to conventional treatments (intraradicular posts, direct composite resin, inlay/onlay). DATA This report followed the PRISMA Statement. A total of 8 studies were included in this review. SOURCES Two reviewers performed a literature search up to February 2016 in seven databases: PubMed, Web of Science, Scopus, BBO, SciELO, LILACS and IBECS. STUDY SELECTION Only clinical trials and in vitro studies that evaluated endocrowns were included. Case reports, case series, pilot studies, reviews and in vitro studies that evaluated properties other than fracture strength of endocrowns were excluded. From the 103 eligible articles, 8 remained in the qualitative analysis (3 clinical trials and 5 in vitro studies), and the meta-analysis was performed for the 5 in vitro studies. A global comparison was performed with random-effects models at a significance level of p<0.05. RESULTS Clinical trials showed a success rate of endocrowns varying from 94 to 100%. The global analysis in posterior and anterior teeth demonstrated that endocrowns had higher fracture strength than conventional treatments (p=0.03). However, when comparing endocrowns to conventional treatments only in posterior teeth (subgroup analyses), no statistically significant differences were found between treatments (p=0.07; I(2)=62%). CONCLUSION The literature suggests that endocrowns may perform similarly or better than the conventional treatments using intraradicular posts, direct composite resin or inlay/onlay restorations. CLINICAL SIGNIFICANCE Although further studies are still necessary to confirm the present findings, endocrowns show potential application for the rehabilitation of severely compromised, endodontically treated teeth.

Water Content in Self-Etching Primers Affects Their Aggressiveness and Strength of Bonding to Ground Enamel

In this study the influence of water concentration in self-etching (SE) primers on their aggressiveness and bond strength to ground enamel was investigated. Five experimental primers with 0, 5, 10, 20, or 40 wt% of water were formulated, using Clearfil SE Bond® (CSEB) as a commercial reference. Primers were applied to bovine incisors following application of bonding resin and composite restoration. Bond strength was evaluated through shear testing and data were statistically analyzed (5%). The etching aggressiveness was evaluated by SEM. Water concentration significantly affected bond strength and etching aggressiveness. The highest bond strength value (MPa) was found for the primer containing 20% of water (24.7), followed by CSEB (23.8). Groups containing 5% (20.5) and 10% (20.2) of water showed an intermediate performance, while the lowest values were observed for the 0% (17.3) and 40% (16.7) groups. SEM analysis showed increasing aggressiveness for increased water content.

Could the application of bioactive molecules improve vital pulp therapy success? A systematic review

This study aimed to systematically review the literature of animal studies to evaluate whether bioactive dentin proteins could improve vital pulp therapy success. The review is reported in accordance with the PRISMA Statement. Two reviewers independently conducted a literature search of seven databases: PubMed (Medline), Lilacs, IBECS, BBO, Web of Science, Scopus, and SciELO. Animal experiments in which bioactive dentin proteins were applied directly or indirectly to the pulp tissue were included. Data regarding the characteristics of the proteins evaluated, the delivery systems used and the main findings from each study were tabulated to assess the outcomes of interest (tertiary dentin formation, inflammatory response, intratubular mineralization). After screening, 32 papers were subjected to qualitative analysis. In 75% of the studies, direct pulp capping was performed. Additionally, the most studied proteins were BMP-7, TGF-β1, and extracted soluble dentin matrix proteins. In conclusion, there is evidence in the literature suggesting that bioactive dentin molecules could enhance tertiary dentin formation with fewer initial inflammatory responses in direct and indirect pulp therapy in animal models. There are potential areas to be explored for novel therapeutic approaches for dental tissue repair and regeneration with bioactive materials.

Aliphatic fatty acids and esters: inhibition of growth and exoenzyme production of Candida, and their cytotoxicity in vitro: anti-Candida effect and cytotoxicity of fatty acids and esters.

The secretion of extracellular phospholipases and proteinases of Candida has been described as a relevant virulence factor in human infections. Aliphatic fatty acids have antimicrobial properties, but the mechanism by which they affect the virulence factors of microorganisms, such as Candida, is still unclear, and there are a few reports about their toxicity. The current study investigated the in vitro antifungal activity, exoenzyme production and cytotoxicity of some aliphatic fatty acids and their ester derivatives against the Candida species. The minimum inhibitory concentration and minimum fungicidal concentrations of aliphatic medium-chain fatty acids, methyl and ethyl esters were performed using the CLSI M27-A3 method and the cytotoxicity assay was performed according to ISO 10993-5. The influence of these compounds in the inhibition of the production of hydrolytic enzymes, phospholipases and proteinases by Candida was also investigated. Data analysis was performed using the one-way ANOVA method (p≤0.05). In relation to the MIC against Candida species, the fatty acid with the best result was Lauric acid, although its ester derivatives showed no activity. The inhibition of phospholipase production was more significant than the inhibition of proteinase production by Candida. Tested fatty acids revealed more than 80% cell viability in their MIC concentrations. Additionally, a cell viability of 100% was reported at concentrations of anti-enzymatic effect. Therefore, the potential use of these fatty acids could be the basis for more antimicrobial tests.

Polypropylene glycol phosphate methacrylate as an alternative acid-functional monomer on self-etching adhesives

OBJECTIVES The aim of this study was to synthesize an alternative acidic monomer (polypropylene glycol phosphate methacrylate--Poly-P) to constitute experimental two-step self-etch adhesive systems and also to evaluate its influence on the pH and microshear bond strength (μSBS) to enamel. METHODS Primers containing Poly-P (10, 15, 30 or 50wt.%), HEMA, ethanol, and water were prepared and allocated in subgroups according to a buffered or non-buffered pH. One experimental control and one commercial (Clearfill™ SE Bond) references were used. μSBS protocol was performed at human enamel, followed by mechanical testing. Scanning electron microscopy (SEM) was performed after each primer application. Data was analysed by one-way Kruskal-Wallis and Student-Newman-Keuls tests (p<0.05) and by linear regression predictive models. RESULTS As greater the Poly-P content, the lower the primers pH. Buffered groups showed lower μSBS values than non-buffered groups. Groups with Poly-P content equal or higher than 30wt.% showed similar μSBS results when compared to the controls. SEM images demonstrated that primers with high Poly-P content etched enamel with prisms exposure. CONCLUSIONS The pH of the primer was directly influenced by the concentration of acidic monomer, which directly affected the adhesion to enamel. Both the acidity and the type of acid-functional monomer present in the adhesive influenced the bond strength results. CLINICAL SIGNIFICANCE Poly-P synthesis was easy and effective, and considering the good bond strength results obtained, this acid-functional monomer may be potentially used in the formulation of self-etch dental adhesive systems.