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This preregistered ex vivo investigation examined the dentinal hybrid layer formation of a resinous infiltrant (Icon), with reference to both thickness (HLT) and homogeneity when combined with modified tunnel preparation (occlusal cavity only) and internal/external caries infiltration. The adhesives Syntac and Scotchbond MP were used as controls (Groups 1 and 3) or in combination with Icon (Groups 2 and 4). A split-tooth design using healthy third molars from 20 donors resulted in 20 prepared dentine cavities per experimental group. The cavity surfaces (n = 80) were etched (37% H3PO4), rinsed, and air-dried. Rewetting with ethanol was followed by application of the respective primers. After labeling with fluorescent dyes, either Syntac Adhesive/Heliobond or Scotchbond MP Adhesive was used alone or supplemented with Icon. HLT, as evaluated by scanning electron microscopy, did not significantly differ (P > 0.05), and confocal laser scanning microscopy revealed homogeneously mixed/polymerized resin-dentine interdiffusion zones in all groups. Icon can be successfully integrated into an ethanol-wet dentine bonding strategy, and will result in compact and homogeneous hybrid layers of comparable thickness considered equivalent to the non-Icon controls, thus allowing for preservation of the tooth's marginal ridge and interdental space in the case of internal/external infiltration of proximal caries.

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OBJECTIVE: The composition of universal adhesives is highly diverse. The purpose of this in vitro study was to compare the shear bond strength of a composite with five different universal adhesives to human enamel and dentin. MATERIALS AND METHODS: The shear bond strength of a composite (G-aenial Universal Injectable) to human enamel and dentin was tested in selective enamel etching mode before and after thermocyclic aging (10,000 cycles) using five different universal adhesive systems (Adhese Universal VivaPen, Clearfil Universal Bond Quick, G-Premio Bond, Prime&Bond active, and Scotchbond Universal Plus). Two-bottle systems (OptiBond FL and G2-Bond Universal) were used as control. Scanning electron microscopy was conducted of the bonding interface. RESULTS: Significant differences in shear bond strength values were found among the five evaluated universal adhesives. Lowest shear bond strength values were observed for 2-hydroxyethylmethacrylate (HEMA)-free systems. Thermocyclic aging did not significantly reduce shear bond strength values indicating that the initial bond remains stable. CONCLUSIONS: The clinical use of universal adhesives Adhese Universal VivaPen, Clearfil Universal Bond Quick, and Scotchbond Universal Plus can be encouraged as they provided comparable or even better shear bond strength values than the two-bottle controls. CLINICAL SIGNIFICANCE: Universal adhesives that were developed for the same indication and approved for clinical use demonstrated variety in shear bond strength values. When applied in the selective enamel etching mode, a stable bond can be expected from adhesives containing HEMA and monomers with phosphate groups.

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This investigation aimed to assess the shear bond strength and fluoride-releasing capabilities of Clearfil Universal Bond Quick (Kuraray Noritake Dental Inc., Tokyo, Japan). Forty-four extracted primary molars were divided into two groups, and the enamel substrate was prepared for evaluating shear bond strength. Scotchbond (3M ESPE) and Clearfil UBQ were used to bond composite-to-enamel substrates in each group (n = 22). Shear bond strength was measured using a universal testing device and compared. Sixteen discs (6 mm diameter and 3 mm thickness) were fabricated from each Clearfil UBQ, Fuji IX, and Fuji II LC. Over the course of 30 days, each materials' fluoride release was examined and compared using ion analysis. Results revealed that Clearfil UBQ had statistically similar shear bond strength to Scotchbond. Between the three materials, Clearfil UBQ had the lowest fluoride release at baseline (0.11 ± 0.25) and the lowest cumulative fluoride release (0.12-0.27 ppm) over 30 days. Fuji IX had the highest fluoride release at baseline (19.38 ± 2.50) and cumulatively (40.87 ± 4.03 ppm), followed by Fuji II LC. We conclude that Clearfil UBQ and Scotchbond showed comparable bond strengths to the enamel. Fluoride release was seen in Clearfil UBQ in the initial two days of the 30-day period. The amount of fluoride release was significantly less than with glass ionomer cements.

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PURPOSE: This study aimed at investigating the surface morphology and nanotopography of normal enamel (NE) and developmentally hypomineralised enamel (HE) when subjected to various pretreatment protocols under scanning electron microscopy (SEM) and atomic force microscopy (AFM). METHODS: Sixteen NE, 16 creamy/white (CW) HE and 16 yellow/brown (YB) HE specimens sectioned from extracted hypomineralised first permanent molars (FPMs) were included in this study. They were randomly distributed into 12 experimental groups (n = 4). Each group involved the following: (1) deproteinisation with Papacarie Duo® gel or no deproteinisation, and (2) the use of Scotchbond™ Universal Adhesive (Scotchbond) in self-etch (SE) mode or 37% phosphoric acid etchant. Subsequently, the surface morphology and nanotopography of pretreated enamel specimens were evaluated under SEM and AFM, respectively. RESULTS: SEM observation showed that deproteinisation with Papacarie Duo® gel before phosphoric acid etching led to favourable etching patterns. This was consistent across all groups irrespective of the type of enamel specimen and the severity of hypomineralisation. In contrast, AFM results identified three factors that influenced surface parameters: (1) type of enamel specimen, (2) severity of hypomineralisation and (3) etching mode. YB HE recorded higher surface roughness values than CW HE and NE when subjected to the same pretreatment protocol. Deproteinisation and the application of Scotchbond in SE mode led to minimal topographic changes; however, acid etching was associated with an increase in surface roughness. CONCLUSION: Deproteinisation with Papacarie Duo® gel followed by acid etching contributed to improved etching patterns on HE.

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PURPOSE: 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). MATERIALS AND METHODS: 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. RESULTS: 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 = 0.028). When subjected to the concurrent use of Papacarie Duo gel and phosphoric acid etching, HE specimens showed a significant increase in µSBS (p < 0.001). CONCLUSION: Deproteinising pretreatment using Papacarie Duo gel followed by the application of SU in E&R mode led to increased µSBS of resin composite to HE.

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OBJECTIVES: This study aimed to assess the microshear bond strength (MSBS) of Scotchbond Universal adhesive, used in self-etch and etch-and-rinse modes, to primary and permanent dentin at 24 hours and six months. MATERIALS AND METHODS: A total of 88 composite micro-cylinders were divided into eight groups (n=11) as follows: (A) Etch-and-rinse, 24 hours, primary dentin; (B) Self-etch, 24 hours, primary dentin; (C) Etch-and-rinse, six months, primary dentin; (D) Self-etch, six months, primary dentin; (E) Etch-and-rinse, 24 hours, permanent dentin; (F) Self-etch, 24 hours, permanent dentin; (G) Etch-and-rinse, six months, permanent dentin; (H) Self-etch, six months, permanent dentin. The MSBS was measured by a testing machine at a crosshead speed of 0.5 mm/minute. Data were analyzed using three-way analysis of variance (ANOVA). RESULTS: The mean MSBS was 12.3±2.3 MPa in A, 18.8±4.1 MPa in B, 11.9±3.7 MPa in C, 16±2.9 MPa in D, 19.1±2.7 MPa in E, 22.8±4.1 MPa in F, 16.2±2.6 MPa in G, and 17.2±4.4 MPa in H. In the self-etch mode, the MSBS was significantly higher than that in the etch-and-rinse mode (P<0.001). The MSBS in permanent teeth was significantly higher than primary teeth (P<0.001). At six months, the MSBS significantly decreased in all groups (P<0.001). CONCLUSION: The micro-shear bond strength of Scotchbond Universal adhesive decreases over time and depends on the type of tooth and the mode of application of the adhesive.

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OBJECTIVE: The aim of this in vitro study was to compare the shear bond strength (SBS) and Adhesive Remnant Index (ARI) scores of two self-etching no-mix adhesives (Prompt L-Pop™ and Scotchbond™) for orthodontic appliances to the commonly used total etch system Transbond XT™ (in combination with phosphoric acid). MATERIALS AND METHODS: In all, 60 human premolars were randomly divided into three groups of 20 specimens each. In group 1 (control), brackets were bonded with Transbond™ XT primer. Prompt L-Pop™ (group 2) and Scotchbond™ Universal (group 3) were used in the experimental groups. Lower premolar brackets were bonded by light curing the adhesive. After 24 h of storage, the shear bond strength (SBS) was measured using a Zwicki 1120 testing machine. The adhesive remnant index (ARI) was determined under 10× magnification. The Kruskal-Wallis test was used to statistically compare the SBS and the ARI scores. RESULTS: No significant differences in the SBS between any of the experimental groups were detected (group 1: 15.49 ± 3.28 MPa; group 2: 13.89 ± 4.95 MPa; group 3: 14.35 ± 3.56 MPa; p = 0.489), nor were there any significant differences in the ARI scores (p = 0.368). CONCLUSIONS: Using the two self-etching no-mix adhesives (Prompt L-Pop™ and Scotchbond™) for orthodontic appliances does not affect either the SBS or ARI scores in comparison with the commonly used total-etch system Transbond™ XT. In addition, Scotchbond™ Universal supports bonding on all types of surfaces (enamel, metal, composite, and porcelain) with no need for additional primers. It might therefore be helpful for simplifying bonding in orthodontic procedures.

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