Surface engineering of silica nanoparticles for oral insulin delivery: characterization and cell toxicity studies

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Root canal filling: fracture strength of fiber-reinforced composite-restored roots and finite element analysis

The aims of this study were to evaluate the effect of root canal filling techniques on root fracture resistance and to analyze, by finite element analysis (FEA), the expansion of the endodontic sealer in two different root canal techniques. Thirty single-rooted human teeth were instrumented with rotary files to a standardized working length of 14 mm. The specimens were embedded in acrylic resin using plastic cylinders as molds, and allocated into 3 groups (n=10): G(lateral) - lateral condensation; G(single-cone) - single cone; G(tagger) - Tagger's hybrid technique. The root canals were prepared to a length of 11 mm with the #3 preparation bur of a tapered glass fiber-reinforced composite post system. All roots received glass fiber posts, which were adhesively cemented and a composite resin core was built. All groups were subjected to a fracture strength test (1 mm/min, 45°). Data were analyzed statistically by one-way ANOVA with a significance level of 5%. FEA was performed using two models: one simulated lateral condensation and Tagger's hybrid technique, and the other one simulated the single-cone technique. The second model was designed with an amount of gutta-percha two times smaller and a sealer layer two times thicker than the first model. The results were analyzed using von Mises stress criteria. One-way ANOVA indicated that the root canal filling technique affected the fracture strength (p=0.004). The G(lateral) and G(tagger) produced similar fracture strength values, while G(single-cone) showed the lowest values. The FEA showed that the single-cone model generated higher stress in the root canal walls. Sealer thickness seems to influence the fracture strength of restored endodontically treated teeth.

Tissue apoptosis in mice infected with Leptospira interrogans serovar Icterohaemorrhagiae

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Synthesis and evaluation of novel prenylated chalcone derivatives as anti-leishmanial and anti-trypanosomal compounds

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação da capacidade seladora apical de um adesivo dentinário, acrescido ou não de hidróxido de cálcio, comparada à de um cimento endodôntico à base de hidróxido de cálcio, na obturação de canais radiculares

Pós-graduação em Odontologia Restauradora - ICT

Efeito dos lasers de Nd:YAG e de Er:YAG na adaptação das obturações de canais radiculares: análise do selamento marginal apical

Pós-graduação em Odontologia Restauradora - ICT

Filmes híbridos PMMA-siloxano modificados com nanotubos de carbono para proteção de materiais metálicos contra corrosão

Using the sol-gel process, organic-inorganic hybrid coatings were synthesized by incorporation of different concentrations of functionalized carbon nanotubes, to improve their mechanical strength and thermal resistance without changing its passivation character. The siloxane-PMMA hybrids were prepared by radical polymerization of methyl methacrylate (MMA) with 3-methacryloxipropiltrimethoxisilane (MPTS) using the thermal initiator benzoyl peroxide (BPO), followed by acid catalyzed hydrolysis and condensation of tetraethoxysilane (TEOS). The analysis of pristine and functionalized carbon nanotubes was carried out using Scanning Electron Microscopy, X-ray Photoelectron Spectroscopy and Raman Spectroscopy. Structural analysis of hybrids was performed by Nuclear Magnetic Resonance, Atomic Force Microscopy and Raman Spectroscopy. For analysis of mechanical strength and thermal stability were performed mechanical compression tests and thermogravimetric analysis, respectively. Electrochemical Impedance Spectroscopy was used to evaluate the corrosion resistance in saline environment. The results showed an effective functionalization of carbon nanotubes with carboxyl groups and conservation of its structure. The hybrids showed high siloxane network connectivity and roughness of approximately 0.3 nm. The incorporation of carbon nanotubes in the hybrid matrix did not change significantly their thermal stability. Samples containing carbon nanotubes exhibit good corrosion resistance (on the order of MΩ in saline environment), but the lack of complete dispersion of carbon nanotubes in the hybrid, resulted in a loss of mechanical and corrosion resistance compared to hybrid matrix.

Efeito da desinfecção e do tempo de armazenagem na molhabilidade de moldes de alginato

The cares at the manipulation of the alginate (condensation, disinfection of the impression and the time elapsed until the leak of the plaster) deserve special attention considering the great amount of distortions occurring every time the impression is not fill of plaster in a brief space of time and appropriate storage conditions. Besides its adaptation to the plaster suffers influence of the events happened after the impression is removed of the mouth. The purpose of this research was to evaluate the wetting capacity of three brands of alginate (Jeltrate™,Hydrogum™ e Orthoprint™) by the plaster type III (Rio™) under the influence of disinfection by sodium hypochlorite 1% sprays and the time of storage of 15 minutes,30 minutes, 1 hour, 6, 12 and 24 hours. There were made 60 impressions of each brand of alginate divided in two groups (water and sodium hypochlorite 1%) rearranged after the application of the sodium hypochlorite spray according to the storage time (15 or 30 minutes and 1,6,12, or 24 hours). On the surface of the impressions 2ml of plaster were flowed, proportioned and condensed in agreement with manufacturer‘s instructions. After the final setting expansion the casts were sectioned vertically and medially, regularized at the cut surface (emery paper 400) and setted for reading the contact angle at the microscope Carl Zeiss. The obtained results, submitted to statistical treatment (ANOVA) revealed significant differences when compared the employed solutions (water and sodium hypochlorite 1%) and the time of storage. The sodium hypochlorite 1% exhibited the smallest contact angles and the times of storage of 15 minutes and 6 hours the smallest and larger angles, respectively. It can be concluded that the alginate impressions exhibited larger adaptation to the plaster when disinfected by hypochlorite of sodium 1% and stocked by 15 minutes.

Restauração transcirúrgica como alternativa na resolução das perfurações endodônticas

The endodontic perforations are iatrogenic communications that result in a communication between the endodonto and periodontium. This occurrence represents about 10 % of cas- es of failure in endodontic treatment. The management may vary and is related to the drilling site endodontic. This paper aims to report a case of iatrogenic perforation and one of the possible alternatives for the treatment of endodontic perforations -level cervical tooth. During the opening coronary perforation occurred due to improper slope cervical penetration drill. Considering the drilling site, we opted for sealing com- posite resin after surgical access and absolute isolation. After sealing, the channel was filled with medication and instru- mented based on calcium hydroxide. Later the canal was obturated by lateral condensation technique with Sealapex. The radiographic follow-up showed regression of the lesion and the clinical silence confirmed the success of the treatment.

Avaliação clínica do clareamento no consultório: técnica de aplicação única do agente clareador

This study aimed to evaluate the clinical effectiveness of two bleaching agents without changing the whitening gel during the clinic session 1X45minutos. 10 patients were selected according to the criteria of inclusion and exclusion and upper arch of the patients were divided into two quadrants (n: 10), G1: gel clareador Clàriant Office (hidrogênio35 Angellus) peroxide% (PH) in superior right side (LD) and the gel WhitenessHp Blue (FGM) PH 35% on the superior left side (LE. 2 clinical sessions were accomplished, 45 minutes each, with an interval of one week between sessions. At first the bleaching treatment patients received prophylaxis, molding to guide measurement of color with condensation silicon and the color evaluation through the apparel spectrophotometer VITA Easyshade (Vita Zhanfabrik, Alemanhã). 14 days after the end of the bleaching treatment was performed the measurement final color of the teeth. The patients reported sensitivity in scale 0-4. The result showed that through T Test comparing quadrants presented no statistical differences (p>0,05) in relation to coloration and dental sensibility. It can be concluded that the materials evaluated are effective for bleaching vital teeth with low tooth sensibility.

Surface modified Mg-doped ZnO QDs for biological imaging

Fundação Amparo à Pesquisa Estado de São Paulo (FAPESP)

Avaliação da promiscuidade catalítica de soroalbuminas em sínteses orgânicas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Resíduos agroindustriais para enriquecimento de fertilizantes orgânicos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Preparação e caracterização de híbridos orgânico-inorgânicos à base de epoxí-silica

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

I. Development of the In Situ Reductive Ozonolysis of Alkenes with Tertiary Amine N-Oxides. II. Progress toward the Asymmetric Synthesis of Peroxyplakoric Acid A3.

Ozone, first discovered in the mid 1800’s, is a triatomic allotrope of oxygen that is a powerful oxidant. For over a century, research has been conducted into the synthetic application and mechanism of reactions of ozone with organic compounds. One of the major areas of interest has been the ozonolysis of alkenes. The production of carbonyl compounds is the most common synthetic application of ozonolysis. The generally accepted mechanism developed by Rudolf Criegee for this reaction involves the 1,3-electrocyclic addition of ozone to the π bond of the alkene to form a 1,2,3-trioxolane or primary ozonide. The primary ozonide is unstable at temperatures above -100 °C and undergoes cycloreversion to produce the carbonyl oxide and carbonyl intermediates. These intermediates then recombine in another 1,3-electrocyclic addition step to form the 1,2,4-trioxolane or final ozonide. While the final ozonide is often isolable, most synthetic applications of ozonolysis require a subsequent reductive or oxidative step to form the desired carbonyl compound. During investigations into the nucleophilic trapping of the reactive carbonyl oxide, it was discovered that when amines were used as additives, an increased amount of reaction time was required in order to consume all of the starting material. Surprisingly, significant amounts of aldehydes and a suppression of ozonide formation also occurred which led to the discovery that amine N-oxides formed by the ozonation of the amine additives in the reaction were intercepting the carbonyl oxide. From the observed production of aldehydes, our proposed mechanism for the in situ reductive ozonolysis reaction with amine N-oxides involves the nucleophilic trapping of the carbonyl oxide intermediate to produce a zwitterionic adduct that fragments into 1O2, amine and the carbonyl thereby avoiding the formation of peroxidic intermediates. With the successful total syntheses of peroxyacarnoates A and D by Dr. Chunping Xu, the asymmetric total synthesis of peroxyplakorate A3 was investigated. The peroxyplakoric acids are cyclic peroxide natural products isolated from the Plakortis species of marine sponge that have been found to exhibit activity against malaria, cancer and fungi. Even though the peroxyplakorates differ from the peroxyacarnoates in the polyunsaturated tail and the head group, the lessons learned from the syntheses of the peroxyacarnoates have proven to be valuable in the asymmetric synthesis of peroxyplakorate A3. The challenges for the asymmetric synthesis of peroxyplakorate A3 include the stereospecific formation of the 3-methoxy-1,2-dioxane core with a propionate head group and the introduction of oxidation sensitive dienyl tail in the presence of a reduction sensitive 1,2-dioxane core. It was found that the stereochemistry of two of the chiral centers could be controlled by an anti-aldol reaction of a chiral propionate followed by the stereospecific intramolecular cyclization of a hydroperoxyacetal. The regioselective ozonolysis of a 1,2-disubstituted alkene in the presence of a terminal alkyne forms the required hydroperoxyacetal as a mixture of diastereomers. Finally, the dienyl tail is introduced by a hydrometallation/iodination of the alkyne to produce a vinyl iodide followed by a palladium catalyzed coupling reaction. While the coupling reaction was unsuccessful in these attempts, it is still believed that the intramolecular cyclization to introduce the 1,2-dioxane core could prove to be a general solution to many other cyclic peroxides natural products.