The effectiveness of glass ionomer cement as a fiber post cementation system in endodontically treated teeth.

This study compared the performance of a glass ionomer (GC Gold Label 1, GIC) as a fiber post cementation system for glass fiber posts with a self-adhesive resin cement (Relyx U200, RUC) and a conventional resin cement system (Scotchbond Muli-Purpose and Relyx ARC, RAC). Thirty endodontically treated canines were randomly divided in three groups (n = 10), according to the fiber post cementation system: (RAC)-Scotchbond Multi-Purpose and Relyx X ARC; (RUC)-Relyx U200 and (GIC)-GC Gold Label 1 Luting & Lining. Rhodamine was incorporated into the cementation system prior to the fiber post cementation. After glass fiber post cementation, roots were incubated in artificial saliva for 6 months. After that, specimens from the cervical, middle, and apical thirds of the post space were prepared and analyzed using a push-out bond strength test and confocal laser microscopy. ANOVA one way and Tukey tests showed that GIC and RUC demonstrated similar push-out bond strength values, independently of the post space third (p > .05); however, values were greater than those shown by RAC (p < .05). For dentin penetrability, GIC and RUC also had similar results (p > 0.05) and lower than RAC (p < 0.05). Inside the root canal, the cementation system using glass ionomer cement (GC Gold Label 1 Luting & Lining) has similar push-out bond strength to the self-adhesive resin cement (Relyx U200) and these were higher than the conventional resin (Relyx ARC), despite its higher dentin penetrability.

Analysis of camphorquinone in composite resins as a function of shade.

OBJECTIVE: To identify and quantify the camphorquinone (CQ) used in different brands of composite resins as a function of the shade analyzed. MATERIALS AND METHODS: Filtek Z250 A3 (FZA3), Filtek Z-250 Incisal (FZI), Pyramid Enamel A1 (PEA1), Pyramid Enamel Translucent (PET), Filtek Supreme A3E (FSA3) and Filtek Supreme GT (FSGT) were used. Five hundred milligrams of each resin were weighed and then dissolved in 1.0 ml of methanol. The samples were centrifuged to accelerate the sedimentation of the inorganic particles. 0.8 ml of the supernatant solution was collected with a pipette and assessed under gas chromatography coupled to the mass spectrometer (GC-MS). The results were compared to pure CQ solutions, used as a standard. Student's t-test, (p=0.05) significant at the level of 5%, compared the results of each brand shade. RESULTS: A smaller amount of camphorquinone was found in Filtek Z-250 (FZI) resin incisal shade when compared to (FZA3) A3 shade. On the other hand, Filtek Supreme resin featured a statistically larger camphorquinone amount in the incisal shade. In Pyramid Enamel resin camphorquinone was found only in shade A1, while the photoinitiator used in the Translucent shade was not identified. SIGNIFICANCE: Based on the data obtained, it is possible to conclude that a single composite resin brand may feature differences in amount and type of photoinitiator used.

Effects of surface treatment on the microtensile bond strength of ceramic materials to dentin.

This study evaluated the effects of distinct surface treatments on the micro-tensile bonding strength (microTBS) of different ceramic materials. The occlusal surfaces of eighteen human maxillary molars were flattened perpendicularly to the long axis and divided in groups based on surface treatment (sandblasting: s; hydrofluoric acid: a; tribochemical silica coating: t): DP-s, DP-a, DP-t, IE-s, IE-a, IE-t, IC-s, IC-a, IC-t) and ceramic materials (Duceran Plus: DP, IPS Empress 2: IE, In-Ceram Alumina, IC). Panavia F luting resins were used according to the manufacturers' instructions to bond ceramic materials to the exposed dentin specimens under a load of 7.5 N. After 3-day storage, microTBS was tested at a cross-head speed of 1 mm/min. Data were analyzed with ANOVA and Tukey's test. ANOVA results showed that the microTBS of DP and IC were significantly different. The microTBS of DP-a was significantly higher than those of DP-s and DP-t. The microTBS of IC-t was significantly higher than those of IC-s and IC-a. Ceramic materials with different chemical formulations and applications yielded significantly different bond strengths to human dentin and must receive distinct surface treatments accordingly.