Thatiana de Vicente Leite

Bio: Thatiana de Vicente Leite is an academic researcher from State University of Campinas. The author has an hindex of 1, co-authored 2 publications receiving 4 citations.

Effect of surface conditioning methods, adhesive systems and resin composite on repair strength of dimethacrylate and silorane resin composites

Abstract: This study evaluated the effect of surface conditioning methods and adhesive systems on the repair bond strength of resin composites. Specimens (FLS: Filtek LS) (N = 144) were prepared using a silicone matrix. The specimens were stored in distilled water and then were randomly divided into the twelve groups (n = 12) according to the surface conditioning method (unground or diamond bur) and adhesive system (no adhesive, LS: Filtek LS, AS: Adper Scotchbond SE Plus) and resin composite (FLS: Filtek LS; FS: Filtek Supreme). The specimens were fixed in an hourglass-shaped silicone matrix and the other half of the specimen was restored. Hourglass-shaped specimens (n = 12) were used as positive control to measure the cohesive strength of the resin composite (Filtek LS). Microtensile bond test was performed (0.5 mm/min) and failure types were analyzed. Data were analyzed using two-way analysis of variance, Tukey’s and Dunnett’s tests (α = 0.05). Adhesive protocol and resin composite significantly affected...

Light curing resin cements containing iodonium salts promote suitable apical bonding of posts to radicular dentin.

Abstract: The aim of this study was to analyze the efficiency of experimental light-curing resin cements (ERCs) with a ternary photo-initiator system containing diphenyliodonium hexafluorphosphate (DPI) and different amines on retention of glass-fiber posts to dentin (GFP). ERCs formulations: a 1:1 mass ratio of 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenylpropane and triethyleneglycol dimethacrylate. Camphorquinone was used as initiator. Six experimental groups were established according to the amine used: [ethyl-4-(dimethylamino)benzoate-EDMAB or 2-(dimethylamino)ethyl methacrylate-DMAEMA] and the concentration of DPI (0, 0.5 mol%, 1 mol%). The resin cements Variolink II (dual- and light-cured versions) were used as commercial reference. Eighty recently extracted bovine incisors (n = 10) were selected for this study. The roots were prepared and the fiber posts were cemented with the resin cement specified for each experimental group. Specimens from coronal, middle, and apical thirds of the root were subjected to push-out bond strength test 24 hours after bonding. Data were subjected to split-plot ANOVA and the Tukey test (p = 0.05). ERCs containing DPI showed statistically significant higher bond strengths compared with ERCs without DPI. ERCs containing DPI were statistically similar to VARIOLINK II – dual-cured and superior to VARIOLINK II – light-cured (except for EDMAB – 1DPI in the medium third and DMAEMA – 1DPI in the coronal third). Different amines did not influence post retention. The apical root region showed the lowest bond strength for the groups EDAB-0DPI, DMAEMA-0DPI and VARIOLINK II light-cured. Light-cured ERCs containing DPI were efficient for GFP retention to radicular dentin, with similar behaviour to that of dual-curing commercial resin cement.

Solvent and HEMA Increase Adhesive Toxicity and Cytokine Release from Dental Pulp Cells

Abstract: The aim of the present study was to evaluate the effect of the hydroxyethyl-methacrylate (HEMA) concentration and solvent content of dental adhesives on cell viability and cytokine (IL-1b, IL-6, IL-10, TNF-α) release by human dental pulp cells (HDPCs). HDPCs were obtained from fresh extracted human third molars. Experimental adhesives were prepared containing different concentrations of HEMA (0%, 10%, and 20%) with and without solvent (ethanol 10%). Cylindrical specimens were immersed on culture medium during 24 h to obtain the extracts. The cells were incubated with extracts (culture medium + components leached from the adhesives) of different adhesives, and cell viability and cytokine release were evaluated after 6 and 24 h of exposure. Adhesives containing HEMA promoted high cell viability reduction after 6 h of exposure; but after 24 h, the results were similar to the ones found among control group cells. These effects on cell viability were prominently increased with the addition of solvent. Although IL-1b release was not affected by exposure to eluates, other cytokines (IL-10, IL-6, TNF-α) were modulated by the different experiment conditions, directly influenced by the HEMA concentration and presence of solvent. Higher HEMA concentrations, combined with the presence of solvent, can promote significant reduction on HDPC viability, increasing the release of anti- and pro-inflammatory mediators.

Does Al2O3 airborne particle abrasion improve repair bond strength of universal adhesives to aged and non-aged nanocomposites?

Abstract: This study investigated the effect of universal adhesives on the resin composite–composite adhesion for immediate and aged repair with and without air-borne particle abrasion. Composite resin speci...

Repair bond strength of dental computer-aided design/computer-aided manufactured ceramics after different surface treatments.

Abstract: Objective To evaluate the microtensile bond strength of four dental computer-aided design/computer-aided manufactured (CAD/CAM) ceramics after application of four different surface treatments. Materials and methods Four dental CAD/CAM ceramics were tested: feldspathic ceramic (VITABLOCKS-Mark II), polymer-infiltrated ceramic network (VITA ENAMIC), zirconia-reinforced lithium silicate (VITA SUPRINITY), and yttria-stabilized zirconia (VITA YZ T). Four surface treatments were applied: no treatment, 5% hydrofluoric acid-etching, airborne particle abrasion, and tribochemical silica coating. The ceramic blocks were repaired with nanohybrid composite (Tetric N-Collection). Sixteen test groups of 12 specimens were prepared. After thermocycling, microtensile bond testing was performed. The microtensile strengths values were statistically analyzed using two-way analysis of variance and Tukey's post-hoc test. Results Repaired feldspathic and resin polymer-infiltrated ceramic network ceramics demonstrated superior microtensile bond strengths compared to zirconia-reinforced lithium silicate and yttria-stabilized zirconia. Etched feldspathic and polymer-infiltrated ceramic network ceramics had higher bond strength than the untreated groups. Surface treatments did not affect the bond strength of zirconia-reinforced lithium silicate and yttria-stabilized zirconia with the exception of etching, which reduced the bond strength of yttria-stabilized zirconia. Conclusion Feldspathic ceramic and polymer-infiltrated ceramic network were repaired with dental composite after surface etching with hydrofluoric acid. Repair of zirconia-reinforced lithium silicate and yttria-stabilized zirconia did not demonstrate promising results. Clinical significance Repair of feldspathic ceramic and polymer-infiltrated ceramic network restorations may be a cost-effective means to promote the longevity of dental restorations. However, zirconia and zirconia-reinforced lithium disilicate restorations do not offer such an option.

Bond strength repair of a bulk-fill composite using different adhesive systems and resin composites

Abstract: In this study evaluated the effect of different adhesive systems and resin composites on the microtensile bond strength of repairs using a bulk-fill composite. Ninety specimens were prepared using a half-hourglass mold of composite Filtek Bulk Fill using a silicone matrix. Specimens were randomly distributed in 9 experimental groups (n=10) according to adhesive [Universal Single Bond (SBU), Scotchbond Multipurpose Adhesive (SBMP), and Single Bond 2 (SB2)] and resin composite (Filtek Bulk Fill, Aura Bulk Fill, and Filtek Z250). For control group, hourglass specimens were used to measure the ultimate bond strength. Specimens were submitted to thermal cycling (5,000 cycles, 5 and 55°C, 30s) to simulate the aging of restoration and then the repair procedure was performed. After the diamond-tipped surface roughening to be repaired, the adhesive protocol was performed according to group, the specimen was placed in an hourglass-shaped mold and the other half was filled with the repair composite. After 24h, bond strength of specimens was obtained by microtensile using a universal testing machine at a speed of 0.5mm/min. Data were statistically analyzed by two-way ANOVA, Tukey’s and Dunnett’s tests (α=0.05). SBU showed higher bond strength compared to SB2, while SBMP showed intermediate values. However, all experimental groups showed lower bond strength compared to ultimate bond strength. In conclusion, bulk-fill composite repair using universal or conventional solvent-free adhesive improved the adhesion independent of composite tested.