Adesivos à base de cianoacrilato para síntese de tecido mole

FUNDAMENTOS - Adesivos teciduais têm sido muito usados para síntese de ferida, em função de ser um método indolor, rápido e de fácil execução. OBJETIVOS -Analisar e comparar compatibilidade dos adesivos, etil- cianoacrilato (Super Bonder) e butilcianoacrilato (Histoacryl), e a reparação de incisões em dorso de ratos entre o fio de sutura e os respectivos adesivos. MÉTODOS - Foram usados 15 ratos. Realizaram-se duas lojas cirúrgicas no dorso. em cada uma, foi implantado um tubo de polietileno (10mm x 1mm), os quais foram preenchidos com os adesivos Super Bonder (lado direito) e Histoacryl (lado esquerdo). As incisões, do lado esquerdo, foram coaptadas com Super Bonder, e as do lado direito, com Histoacryl. Uma incisão mediana, entre as duas incisões,foi realizada e suturada com fio de seda. Os animais foram mortos, depois de 7(sete), 35(trinta) e 120 (cento e vinte dia) dias. RESULTADOS: Os adesivos usados, no presente estudo, não promoveram reação inflamatória, quando usados para síntese das incisões. Porém, estes adesivos, quando implantados no subcutâneo, promoveram reação inflamatória até 120 (cento e vinte dia) dias, no entanto, a reação é mais intensa com Histoacryl. CONCLUSÕES: Super Bonder e Histoacryl permitem o processo cicatricial dos tecidos incisados; facilitam a sutura das incisões. Desta forma, estes podem ser utilizados para sínteses de feridas, lacerações ou incisões cutâneas.

Effect of microwave disinfection on the bond strength of denture teeth to acrylic resins

During microwave disinfection, the dentures are exposed to water at high temperature and this may affect the bond between the denture teeth and the acrylic resin from which dentures are made. In this study, a shear test was used to evaluate the effect of microwave disinfection (650W/6 min) on the bond strength of two types of denture teeth to three acrylic resins, with different polymerization methods. The specimens were submitted to the shear tests (0.5 mm/min) after: immersion in water (37 degrees C) for 48 h or 8 days (controls); two or seven cycles of microwave disinfection (test groups). Data (MPa) were analyzed using three-way ANOVA and Tukey HSD test (alpha = 0.05). Microwave disinfection did not adversely affect the bond strength of all tested materials with the exception of QC-20 bonded to SR Vivodent PE, for which a significant reduction was recorded after seven cycles of irradiation. (C) 2007 Elsevier Ltd. All rights reserved.

Evaluation of n-Butyl Cyanoacrylate Adhesive in Rat Subcutaneous Tissue

Background Tissue adhesives have been widely used for wound closure, especially in children, because they are painless, fast, and easy to use and result in minimal scarring.Objective To analyze the biocompatibility of an adhesive based on n-butyl-cyanoacrylate in the subcutaneous tissue of rats.Materials and Methods Two surgical sites were prepared (approximately 3 cm apart): one on the left side of the animal and the other on the right side); polyethylene tubes were implanted in each surgical site. The tube on the left was filled with n-butyl-cyanoacrylate (treated group) and the tube on the right side was unfilled (control group). After 7, 30, and 120 days, the animals were killed, and the specimens were processed for histologic analysis.Results No significant inflammatory reaction occurred in the treated group, showing results similar to the control group.Conclusion This adhesive based on n-butyl-cyanoacrylate is biocompatible in the subcutaneous tissue of rats.

Influence of Er,Cr: YSGG laser on bond strength of self-adhesive resin cement

The purpose of this study was to investigate the bond strength of fiber post previously laser treated root canals. Forty single-rooted bovine teeth were endodontically treated, randomly and equally divided into two main groups according to the type of pretreatment: G1: 2.5% NaOCl (control group); and G2: Er,Cr:YSGG laser. Each group was further subdivided into 2 groups based on the category of adhesive systems/ luting materials used: a: an etch-and-rinse resin cement (Single Bond/RelyX ARC; 3M ESPE), and b: a self-adhesive resin cement (Rely X Unicem; 3M ESPE). Three 1.5 mm thick slabs were obtained per root and the push-out test was performed at a crosshead speed of 0.5 mm/min until post dislodgement occurred. Data were analyzed by ANOVA and post-hoc Tukey's test at a pre-set alpha of 0.05. Analysis of variance showed no statistically significant difference (p > 0.05) among the groups G1a (25.44 ± 2.35) and G1b (23.62 ± 3.48), G2a (11.77 ± 2.67) and G2b (9.93 ± 3.37). Fractures were observed at the interface between the dentin and the resin in all groups. The Er,Cr:YSGG laser irradiation did not influence on the bond strength of the resin cements and the etch-and-rinse resin cement had better results on bond strength than self-adhesive resin cement.

Fracture resistance of bleached teeth restored with different procedures

This study evaluated the fracture resistance of teeth submitted to internal bleaching and restored with different non-metallic post. Eighty mandibular incisors were endodontically treated and randomly divided in 10 groups (n = 8): G1- restored with composite resin (CR), G2- CR + fiber-reinforced composite post (FRC, Everstick post, Sticktech) cemented with resin cement self-etch adhesive (RCS, Panavia F 2.0, Kuraray), G3- CR + FRC + self-adhesive resin cement (SRC, Breeze, Pentral Clinical), G4- CR+ glass fiber post (GF, Exacto Post, Angelus) + RCS, G5- CR + GF + SRC. The G6 to G10 were bleached with hydrogen peroxide (HP) and restored with the same restorative procedures used for G1 to G5, respectively. After 7 days storage in artificial saliva, the specimens were submitted to the compressive strength test (N) at 0.5 mm/min cross-head speed and the failure pattern was identified as either reparable (failure showed until 2 mm below the cement-enamel junction) or irreparable (the failure showed <2 mm or more below the cement-enamel). Data were analyzed by ANOVA and Tukey test (α = 0.05). No significant difference (p < 0.05) was found among G1 to G10. The results suggest that intracoronal bleaching did not significantly weaken the teeth and the failure patterns were predominately reparable for all groups. The non-metallic posts in these teeth did not improve fracture resistance.

Factors affecting on bond strength of glass fiber post cemented with different resin cements to root canal

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Marginal adaptation of Class 2 adhesive restorations

Objective: Control of microleakage represents a challenge for posterior composite restorations. The technique for composite placement may reduce microleakage. The null hypothesis of this in vitro study was that centripetal incremental insertion of composite resin would result in less microleakage than that obtained with the oblique incremental technique or bulk technique. Method and Materials: Standardized Class 2 preparations were made in 60 caries-free extracted third molars and randomly assigned to 3 groups ( n = 20): ( 1) oblique incremental insertion technique ( control), ( 2) centripetal incremental insertion technique, and ( 3) bulk insertion. The teeth were restored with a total-etch adhesive and micro-hybrid composite resin. The specimens were isolated with nail varnish except for a 2-mm-wide area around the restoration and then thermocycled ( 1,000 thermal cycles, 5 degrees C/ 55 degrees C; 30-second dwell time). The specimens were immersed in an aqueous solution of 50% silver nitrate for 24 hours, followed by 8 hours of immersion in a photo-developing solution and subsequently evaluated for leakage. The microleakage scores ( 0 to 4) obtained from the occlusal and cervical walls were analyzed with median nonparametric tests ( P <.05). Results: The null hypothesis was rejected. All techniques attained statistically similar dentin microleakage scores ( P =.15). The centripetal insertion technique displayed significantly less microleakage than the oblique technique at the enamel margins ( P =.04). Conclusion: None of the techniques eliminated marginal microleakage in Class 2 preparations. However, in occlusal areas, the centripetal technique performed significantly better than the other techniques.

Effect of Resin Cement System and Root Region on the Push-out Bond Strength of a Translucent Fiber Post

Objectives: This study evaluated the bond strength of luting systems for bonding glass fiber posts to root canal dentin. The hypothesis tested was that there are no differences in bond strength of glass fiber posts luted with different cement systems.Methods: Forty bovine incisors were randomly assigned to five different resin cement groups (n=8). After endodontic treatment and crown removal, translucent glass fiber posts were bonded into the root canal using five different luting protocols (self-cured cement and etch-and-rinse adhesive system; dual-cured cement and etch-and-rinse adhesive system; self-cured cement and self-etch adhesive system; dual-cured cement and self-etch adhesive system; and dual-cured self-adhesive cement). Push-out bond strength was evaluated at three different radicular levels: cervical, middle, and apical. The interface between resinous cement and the post was observed using a stereoscopic microscope.Results: Analysis of variance showed a statistically significant difference among the cements (p<0.05) and the root canal thirds (p<0.05). The self-adhesive resinous cement had lower values of retention.Conclusions: The resin cements used with etch-and-rinse and self-etch adhesive systems seem to be adequate for glass fiber post cementation.

Comparative scanning electron microscopic study of the effect of different dental conditioners on dentin micromorphology

This study evaluated comparatively by scanning electron microscopy (SEM) the effect of different dental conditioners on dentin micromorphology, when used according to the same protocol. Forty dentin sticks were obtained from 20 caries-free third human molars and were assigned to 4 groups corresponding to 3 conditioners (phosphoric acid 37%, Clearfil SE Bond and iBond) and an untreated control group. After application of the conditioners, the specimens were immersed in 50% ethanol solution during 10 s, chemically fixed and dehydrated to prepare them to SEM analysis. In the control group, dentin surface was completely covered by smear layer and all dentinal tubules were occluded. In the phosphoric acid-etched group, dentin surface was completely clean and presented exposed dentinal tubule openings; this was the only group in which the tubules exhibited the funnel-shaped aspect. In the groups conditioned with Clearfil SE Bond primer and iBond, which are less acidic than phosphoric acid, tubule openings were occluded or partially occluded, though smear layer removal was observed. SE Bond was more efficient in removing the smear layer than iBond. In the Clearfil SE Bond group, the cuff-like aspect of peritubular dentin was more evident. It may be concluded all tested conditioners were able to change dentin morphology. However, it cannot be stated that the agent aggressiveness was the only cause of the micromorphological alterations because a single morphological pattern was not established for each group, but rather an association of different aspects, according to the aggressiveness of the tested conditioner.

Analysis of depth of the microporosity in a nickel-chromium system alloy: effects of electrolytic, chemical and sandblasting etching

The present study was designed to analyse the average depth of the microporosity of a nickel-chromium (Ni-Cr) system alloy (Verabond II). The metal surface was subject to one of the following surface treatment: (i) Electrolytic etching in nitric acid 0.5 N at a current density of 250 mA cm(-2) ; (ii) chemical etching with CG-Etch etchant; and (iii) Sandblasting with alumina particles 50 mum. Half of the samples were polished before the surface treatments. The depth of porosity was measured through photomicrographs (500x) with a profilometer, and the data were statistically analysed using an analysis of variance (anova) followed by Tukey's test. The conclusions were (i) Differents surface treatment of the Ni-Cr system alloy lead to different depths of microporosity; (ii) the greatest depth of porosity was observed in non-polished alloy; (iii) the greatest and identical depth of microporosity was observed following electrolytic etching and chemical etching; (iv) the least and identical depth of microporosity was observed with chemical etching and sandblasting with alumina particles 50 mum, and (v) Chemical etching showed an intermediary depth.

Effect of Static and Cyclic Loading on Ceramic Laminate Veneers Adhered to Teeth with and Without Aged Composite Restorations

Purpose: Existing composite restorations on teeth are often remade prior to the cementation of fixed dental prostheses. The aim of this study was to evaluate the effect of static and cyclic loading on ceramic laminate veneers adhered to aged resin composite restorations.Materials and Methods: Eighty sound maxillary incisors were collected and randomly divided into four groups: group 1: control group, no restorations; group 2: two Class III restorations; group 3: two Class IV restorations; group 4: complete composite substrate. Standard composite restorations were made using a microhybrid resin composite (Anterior Shine). Restored teeth were subjected to thermocycling (6000 cycles). Window preparations were made on the labial surface of the teeth for ceramic laminate fabrication (Empress II). Teeth were conditioned using an etch-and-rinse system. Existing composite restorations representing the aged composites were silica coated (CoJet) and silanized (ESPE-Sil). Ceramic laminates were cemented using a bis-GMA-based cement (Variolink Veneer). The specimens were randomly divided into two groups and were subjected to either static (groups 1a, 2a, 3a, 4a) or cyclic loading (groups 1b, 2b, 3b, 4b). Failure type and location after loading were classified. Data were analyzed using one-way ANOVA and Tukey's test.Results: Significantly higher fracture strength was obtained in group 4 (330 +/- 81 N) compared to the controls in group 1 (179 +/- 120 N) (one-way ANOVA, p < 0.05). Group lb survived a lower mean number of cyclic loads (672,820 cycles) than teeth of groups 2b to 4b (846x10(3) to 873x10(3) cycles). Failure type evaluation after the fracture test showed predominantly adhesive failures between dentin and cement, but after cyclic loading, more cohesive fractures in the ceramic were seen.Conclusion: Ceramic laminate veneers bonded to conditioned aged composite restorations provided favorable results. Surface conditioning of existing restorations may eliminate the necessity of removing aged composite restorations.

Bonding Efficacy of New Self-etching, Self-adhesive Dual-curing Resin Cements to Dental Enamel

Purpose: This study evaluated the efficacy of the union between two new self-etching self-adhesive resin cements and enamel using the microtensile bond strength test.Materials and Methods: Buccal enamel of 80 bovine teeth was submitted to finishing and polishing with metallographic paper to a refinement of #600, in order to obtain a 5-mm(2) flat area. Blocks (2 x 4 x 4 mm) of laboratory composite resin were cemented to enamel according to different protocols: (1) untreated enamel + RelyX Unicem cement (RX group); (2) untreated enamel + Bifix SE cement (BF group); (3) enamel acid etching and application of resin adhesive Single Bond + RelyX Unicem (RXA group); (4) enamel acid etching and application of resin adhesive Solobond M + Bifix SE (BFA group). After 7 days of storage in distillated water at 37 degrees C, the blocks were sectioned for obtaining microbar specimens with an adhesive area of 1 mm(2) (n = 120). Specimens were submitted to the microtensile bond strength test at a crosshead speed of 0.5 mm/min. The results (in MPa) were analyzed statistically by ANOVA and Tu key's test.Results: Enamel pre-treatment with phosphoric acid and resin adhesive (27.9 and 30.3 for RXA and BFA groups) significantly improved (p <= 0.05) the adhesion of both cements to enamel compared to the union achieved with as-polished enamel (9.9 and 6.0 for RX and BF).Conclusion: Enamel pre-treatment with acid etching and the application of resin adhesive significantly improved the bond efficacy of both luting agents compared to the union achieved with as-polished enamel.

Effects of Self-Etching Adhesive Systems Used in the Dental Modelling Technique on the Cohesive Strength of Composite Resin

This study evaluated the cohesive strength of composite using self-etching adhesive systems (SE) in the lubrication of instruments between layers of composite. The specimens were made by using a Teflon (R) device. SE were used at the interface to lubricate the instruments: Group 1(G1) - control group, no lubricant was used; Group 2(G2) -Futurabond (R) M; Group 3(G3) - Optibond (R) All-In-One; Group 4(G4) - Clearfil (R) SE Bond; Group 5(G5) - Futurabond (R) NR; Group 6(G6) - Adper (R) SE Plus; Group 7(G7) - One Up Bond (R) F. Specimens were submitted to the tensile test to evaluate the cohesive strength. Data were submitted to the ANOVA and Tukey tests. ANOVA showed a value of p = 0.00. The average means (SD): G2 = 11.33(+/-3.44) a, G3 = 15.36(+/-4.06) ab, G4 = 18.9(+/-4.72) bc, G7 = 19.62(+/-4.46) bc, G5 = 21.02(+/-5.09) bc, G6 = 23.39(+/-4.17) cd, and G1 = 28.49(+/-2.89) d. All SE decreased the cohesive strength of the composite, except for Adper (R) SE Plus.

Evaluation of Bond Strength of Self-adhesive Cements to Dentin With or Without Application of Adhesive Systems

Purpose: To evaluate the bond strength of indirect restorations to dentin using self-adhesive cements with and without the application of adhesive systems.Material and Methods: Seventy-two bovine incisors were used, in which the buccal surfaces were ground down to expose an area of dentin measuring a minimum of 4 x 4 mm. The indirect resin composite Resilab was used to make 72 blocks, which were cemented onto the dentin surface of the teeth and divided into 4 groups (n = 18): group 1: self-adhesive resin cement BiFix SE, applied according to manufacturer's recommendations; group 2: self-adhesive resin cement RelyX Unicem, used according to manufacturer's recommendations; group 3: etch-and-rinse Solobond M adhesive system + BiFix SE; group 4: etch-and-rinse Single Bond 2 adhesive system + RelyX Unicem. The specimens were sectioned into sticks and subjected to microtensile testing in a universal testing machine (EMIC DL-200MF). Data were subjected to one-way ANOVA and Tukey's test (alpha = 5%).Results: The mean values (+/- standard deviation) obtained for the groups were: group 1: 15.28 (+/- 8.17)(a), group 2: 14.60 (+/- 5.21)(a), group 3: 39.20 (+/- 9.98)(c), group 4: 27.59 (+/- 6.57)(b). Different letters indicate significant differences (ANOVA; p = 0.0000).Conclusion: The application of adhesive systems before self-adhesive cements significantly increased the bond strength to dentin. In group 2, RelyX Unicem associated with the adhesive system Single Bond 2 showed significantly lower mean tensile bond strengths than group 3 (BiFix SE associated with the etch-and-rinse Solobond M adhesive system).

Effect of Biomimetic Remineralization on the Dynamic Nanomechanical Properties of Dentin Hybrid Layers

The mineral and organic phases of mineralized dentin contribute co-operatively to its strength and toughness. This study tested the null hypothesis that there is no difference in nano-dynamic mechanical behavior (complex modulus-E*; loss modulus-E ''; storage modulus-E'; in GPa) of dentin hybrid layers (baseline: E*, 3.86 +/- 0.24; E '', 0.23 +/- 0.05; E', 3.85 +/- 0.24) created by an etch-and-rinse adhesive in the presence or absence of biomimetic remineralization after in vitro aging. Using scanning probe microscopy and nano-dynamic mechanical analysis, we demonstrated that biomimetic remineralization restored the nano-dynamic mechanical behavior of heavily remineralized, resin-sparse regions of dentin hybrid layers (E*, 19.73 +/- 3.85; E '', 8.75 +/- 3.97; E', 16.02 +/- 2.58) to those of the mineralized dentin base (E*, 19.20 +/- 2.42; E '', 6.57 +/- 1.96; E', 17.39 +/- 2.0) [p > 0.05]. Conversely, those resin-sparse, water-rich regions degraded in the absence of biomimetic remineralization, with significant decline [p < 0.05] in their complex and storage moduli (E*, 0.83 +/- 0.35; E '', 0.88 +/- 0.24; E', 0.62 +/- 0.32). Intrafibrillar apatite deposition preserves the integrity of resin-sparse regions of hybrid layers by restoring their nanomechanical properties to those exhibited by mineralized dentin.