Thompsonnolan0688

To evaluate the effect of different HF-etching protocols on the dissolution depth and micromorphology of the etched and adjacent surfaces of ultrathin glass-ceramic specimens.

One hundred twenty specimens (6 x 6 x 0.3 mm) of leucite-reinforced glass-ceramic (LEU, IPS Empress, Ivoclar Vivadent) and lithium-disilicate-reinforced glass-ceramic (LD, IPS e.max, Ivoclar Vivadent) were prepared. Fedratinib Specimens were divided into 5 groups (n = 12) according to etching protocol G1 control, untreated; G2 5% hydrofluoric acid (HF) etching for 20 s (HF5%20s); G3 HF5%60s; G4 HF10%20s; and G5 HF10%60s. To analyze the dissolution depth, specimens were sectioned into two similarly sized halves using a chisel to create an internal surface (IS). Specimens were analyzed with scanning electron microscopy (SEM) on the following surfaces HF application surface (AS), lateral surface (LS), internal surface (IS), and the surface opposite to the AS (OS). Dissolution patterns were identified. Data were submitted to one-way ANOVAths can be formed which are dependent of hydrofluoric acid concentration, application time, and proportion of the glass phase in the ceramic.

Hydrofluoric acid etching not only affects the surface upon which it is applied, but internal, lateral and even opposite edges of glass ceramic. Different dissolution patterns and depths can be formed which are dependent of hydrofluoric acid concentration, application time, and proportion of the glass phase in the ceramic.

To investigate the bond strength and durability of a novel dual-curing composite cement to zirconia under different curing conditions.

Zirconia plates of different thickness (0.5, 1, and 2 mm) were bonded with either a novel dual-curing composite cement (Panavia V5, PV5, Kuraray Noritake) or a traditional one (RelyX Ultimate, RUL, 3M Oral Care; Multilink Automix, MLA, Ivoclar Vivadent), in light-, self-, or dual-curing mode. Bonded specimens were subjected to shear bond strength (SBS) tests after 24 h of water storage or after artificially aging by 20,000 thermal cycles plus 150 days of water storage. The degree of conversion (DC) of the composite cements under different curing conditions was measured by Fourier transform infrared (FTIR) spectroscopy. The irradiance and translucency of the zirconia plates of different thickness were also investigated.

The irradiance and translucency of zirconia decreased significantly with increasing thickness (p = 0.00). Both before and after aging, SBS of PV5 iient, PV5 provides improved bond strength and durability to zirconia.

When the photoactivation time is 60 s and the thickness of the zirconia restoration is less than 2 mm, it is safe to use the two traditional dual-curing composite cements RUL and MLA and PV5 for bonding zirconia. However, when the light exposure time is insufficient, PV5 provides improved bond strength and durability to zirconia.

To investigate the effects of four commercial silver diamine fluoride (SDF) agents on the chemical composition and microstructural properties of dentin, and its relation to the bond strength of two adhesives.

Ninety human molars were randomly divided into sound dentin (negative control), demineralized dentin (positive control), and four experimental groups (n = 15) according to the SDF treatments (Cariestop [Biodinamica Quimica y Farmaceutica], RivaStar 1 [SDI], RivaStar 2 [SDI], and Saforide [Tokyo Seiyaku Kasei]). ATR-FTIR, x-ray diffraction, and SEM techniques were employed to characterize the compositional, crystalline, and microstructural properties of the samples. The microtensile bond strength test evaluated the bonding performance of two adhesives in demineralized dentin treated with SDF agents.

Regarding the chemical composition, all SDF-treated groups showed a significantly higher phosphateorganic matrix ratio than the demineralized dentin group (p < 0.05). The XRD analyses revealed that the crystallite size for hydroxyapatite crystals increased on the surface areas (deep, medium, and superficial dentin) for all experimental groups compared to demineralized dentin (p < 0.05). SEM images showed that the behavior of the agents used differs on each surface treated. Bond strength values were adversely affected with both adhesive systems in the four experimental groups (p < 0.05).

The application of SDF agents resulted in the formation of different crystalline phases of silver salts and the increase of mineralization of the pretreated demineralized dentin. However, SDF application showed a negative effect on the bond strength of the adhesives.

The application of SDF agents resulted in the formation of different crystalline phases of silver salts and the increase of mineralization of the pretreated demineralized dentin. However, SDF application showed a negative effect on the bond strength of the adhesives.

To evaluate the effect of heated and room-temperature hydrofluoric (HF) acid on surface roughness parameters (Ra and Rq) and microtensile bond strength (μTBS) on feldspathic ceramic and lithium-disilicate glass-ceramics.

Disk-shaped samples made from both ceramics were divided into groups according to surface treatment feldspathic ceramic polished surface (FP), feldspathic ceramic + 60 s of 9% HF acid etching at room temperature (FC), feldspathic ceramic + 60 s of 9% HF acid etching heated to 70°C (F70), lithium-disilicate polished surface only (LP), lithium disilicate + 20 s of 9% HF acid etching at room temperature (LC), and lithium disilicate + 20 s of 9% HF acid etching heated to 70°C (L70). To evaluate Ra and Rq, non-overlapping readings were taken on the surface of each sample with a contact stylus profilometer. To measure microtensile bond strength (μTBS), samples of groups FC, F70, LC and L70 received their corresponding surface treatment, were silanized and then bonded using a dual-cure com ± 4.14), F70 (18.24 ± 5.29), and LC (17.87 ± 6.96).

The use of 9% HF acid etching heated to 70°C resulted in significantly higher surface roughness and improved bond strength onto lithium-disilicate glass-ceramic compared to surface HF acid etching at room temperature.

The use of 9% HF acid etching heated to 70°C resulted in significantly higher surface roughness and improved bond strength onto lithium-disilicate glass-ceramic compared to surface HF acid etching at room temperature.

To validate the rationale of using a conventional light-curing resin-based composite (RBC) to lute thick indirect restorations by measuring mini-interfacial fracture toughness (mini-iFT).

Freshly exposed dentin of extracted third molars (n = 64) was immediately sealed with a thin layer of an experimental RBC with a 50 wt% or 75 wt% (IDS) filler load. Two- or 6-mm-thick CAD/CAM composite blocks were luted onto IDS using either pre-heated light-cure or dual-cure luting RBC, with the latter having served as control. Samples were cut into sticks, upon which a notch was prepared at the interface between IDS and luting RBC, prior to being submitted to a 4-point bending test to determine mini-iFT. The results were analyzed using a mixed linear model (LME). Failure mode at the fractured interface was determined using scanning electron microscopy (SEM).

LME revealed that mini-iFT was not significantly affected by the composite block thickness (p = 0.39), but by the luting RBC (p < 0.0001) and the IDS RBC filler load (p = 0.0011). Mini-iFT was higher with 50 wt% filler-loaded RBC IDS and when luted using the light-curing RBC.

This work provides the proof of concept that 2- and 6-mm-thick indirect restorations can safely be adhesively luted with pre-heated conventional light-cure RBC under controlled light-irradiation conditions. This strategy even seems beneficial in terms of mini-iFT compared to using a dual-cure luting RBC. IDS with lower filler content also appeared more favorable.

This work provides the proof of concept that 2- and 6-mm-thick indirect restorations can safely be adhesively luted with pre-heated conventional light-cure RBC under controlled light-irradiation conditions. This strategy even seems beneficial in terms of mini-iFT compared to using a dual-cure luting RBC. IDS with lower filler content also appeared more favorable.

To characterize experimental adhesives containing natural antimicrobial agents (proanthocyanidins, apigenin, tt-farnesol) in the primer and to evaluate their anti-caries effect.

Natural agents were incorporated in the primer of an experimental adhesive 4.5% proanthocyanidins (PA), 1 mM apigenin (API), 1 mM apigenin + 5 mM tt-farnesol (API + FAR), and primer without antimicrobial agent (control). Microtensile bond strength (μTBS) to dentin and nanoleakage were measured immediately (n = 7) and after 1 year of storage (n = 7). Water sorption (WS), solubility (SO), and degree of conversion (DC%) of the adhesives were measured. The hardness loss of enamel (n = 6) and dentin (n = 6) at the restorative margin was evaluated after biofilm formation.

DC%, nanoleakage, and immediate μTBS were similar for all groups. After 1 year, API + FAR showed higher nanoleakage and lower μTBS than the other groups, which were similar. WS and SO of API + FAR were lower than in the other groups. PA, API, and API + FAR presented less hardness loss than did the control group. At enamel, PA and API presented less hardness loss than the control and API + FAR groups at distances 50 µm and 100 µm; the hardness loss of enamel was similar for all groups 150 µm from the margin.

The addition of proanthocyanidins and apigenin to the adhesives decreased the hardness loss of dentin and enamel submitted to biofilm formation, without jeopardizing the physical properties of the adhesives. The combination of apigenin + tt-farnesol decreased the hardness loss of dentin but not of enamel, and decreased the μTBS after 1 year of storage.

The addition of proanthocyanidins and apigenin to the adhesives decreased the hardness loss of dentin and enamel submitted to biofilm formation, without jeopardizing the physical properties of the adhesives. The combination of apigenin + tt-farnesol decreased the hardness loss of dentin but not of enamel, and decreased the μTBS after 1 year of storage.

To investigate the effect of pretreatment protocols involving Papacarie Duo gel and Scotchbond Universal (SU) on the microshear bond strength (µSBS) of resin composite (RC) to hypomineralised enamel (HE).

Specimens of normal enamel (NE) and HE were derived from extracted hypomineralised first permanent molars (FPMs). Based on the colour of demarcated opacities, HE specimens were classified as creamy/white (CW) or yellow/brown (YB). The specimens were randomly allocated into eight groups (n = 20). Each group involved pretreatment with Papacarie Duo gel or no pretreatment, and SU applied in etch-and-rinse (E&R) or self-etch (SE) mode. All specimens were bonded with RC and subjected to µSBS testing. Failure modes were analysed using an optical microscope and SEM.

Comparing NE with HE, the following factors were found to be significant (p < 0.001) type of enamel substrate, deproteinising pretreatment, and etching mode. Comparing CW HE with YB HE, a significant interaction between "deproteinising pretreatment" and "etching mode" was demonstrated (p = 0.