"Effect of different application modalities and temperature of warm-air evaporation on the bonding performance of four adhesive systems to dentin"

Description :

In this study, bond strength, biological, and morphological characterizations of resin-bond interfaces will be performed according to these factors: (1) adhesive system (Three-step etch-and-rinse, Optibond FL; two-step self-etch, Clearfil SE Bond; HEMA-free Universal Adhesive, Prime&Bond Universal; and HEMA-Containing Universal Adhesive, Single Bond Universal); (2) application modalities (passive application, active application, ultrasonic application, and vibration with COMPO-VIBES); (3) adhesive layer application (one coat of adhesive will be applied with the active technique; application of the first layer with the active technique, the second layer without the active technique, and the third layer without the active technique; application of the first layer with the active technique, the second layer with the active technique, and the third layer without the active technique; application of the first, second, and the third layer with the active technique); (4) air-dry temperature used for solvent evaporation (20°C, 40°C, and 60°C); (5) aging (24 h and 6 months). 1. Protocols for the different application modalities Four groups based on the application modalities (passive application, active application, ultrasonic application, and vibration with COMPO-VIBES) will be used. The sample size (n=5) was estimated based on a previous study [33] that evaluated the effect of different application modes on the bond strength to dentin in a comparative study design with 4 independent groups, a 9.3 minimum detectable difference in means, a 5.2 standard deviation, power of 0.8, and an a=.05. a- For passive application: All adhesives tested will be applied and left undisturbed according to the manufacturer’s instructions. b- For active application: All adhesives tested will be applied with active agitation according to the manufacturer’s instructions. c- For ultrasonic application: All adhesives tested will be applied with microbrush applicator (Kerr, Orange, CA, USA), which the shank of microbrush will be continuously touched while its application with a tip of ultrasonic instrument (Piezon Master 400, EMS, Le Sentier, Switzerland) set at a frequency of 27–30 kHz. d- For vibration with COMPO-VIBES: All adhesives tested will be applied with COMPO-VIBES (Smile Line, Switzerland) instrument (This could be possible with the help of COMPO-VIBES tip for bonding). 2. Protocols for the different layer application Four groups based on the adhesive layer application including the triple adhesive layers and active bonding technique. One coat (control), and three coats of adhesives will be applied according to the manufacturer’s instructions without light curing after each application. Active application of adhesives to dentinal substrate will be applied manually using microbrush applicator (Kerr, Orange, CA, USA). The number of specimens per group (n=5) was estimated based on a previous study [34] that evaluated the effect of multiple layer application on the bond strength to dentin in a comparative study design with 4 independent groups, a 5.87 minimum detectable difference in means, a 1.54 standard deviation, power of 0.8, and an a=.05. a- First group: Application of one coat of adhesive with the active technique and according to the instructions of the manufacturer (control). b- Second group: Application of the first layer with the active technique, the second layer without the active technique, and the third layer without the active technique. c- Third group: Application of the first layer with the active technique, the second layer with the active technique, and the third layer without the active technique. d- Group four: Application of the first, second, and the third layer with the active technique. 3. Protocols for the air-dry temperature Three groups based on the air-dry temperature used: solvent evaporation will be performed either with warm (40°C), (60°C), and cold air as control group (20°C) for 10 s at a distance of 10 cm. In all three cases, the air stream was generated by a pen type device (or a device attached to the triple function syringe) for delivering warm or cold air. The air speed of the stream will be 5.50 m/s and the air flow will be 0.0138 m3/s. The pen type device (or the device attached to the triple function syringe) is a prototype that is manufactured by an electrical engineer and will be tested according to iso standard number etc…. The number of specimens per group (n=5) was estimated based on a previous study [35] that evaluated the effect of warm air application for solvent evaporation on the bond strength to dentin in a comparative study design with 3 independent groups, a 8.8 minimum detectable difference in means, a 2.9 standard deviation, power of 0.8, and an a=.05.