Effects of C-factor on dentin bonding using various adhesive systems.

Area of Science:

• Dental Materials Science
• Adhesive Dentistry
• Biomaterials

Background:

• The C-factor (configuration factor) influences the stress experienced by adhesive interfaces in dental restorations.
• Understanding C-factor effects is crucial for optimizing resin composite bonding to dentin.
• Dentin substrate geometry (wall vs. floor) can affect adhesive bond strength.

Purpose of the Study:

• To evaluate the impact of C-factor on the microtensile bond strength of resin composite to different dentin surfaces (floor and wall).
• To compare the performance of three different adhesive systems under varying C-factor conditions.
• To determine how cavity preparation geometry influences bond strength compared to flat surfaces.

Main Methods:

• Four dentin substrate types were prepared: flat wall, flat floor, cavity wall, and cavity floor.
• Human molars were restored using Clearfil SE Bond, Single Bond, or Clearfil tri-S Bond, followed by Z100 resin composite buildup.
• Microtensile bond strength specimens were prepared and tested after light curing.
• Statistical analysis was performed to compare bond strengths across groups.

Main Results:

• All tested adhesive systems demonstrated the highest bond strength to the flat wall dentin group.
• Bond strength to cavity preparations (wall and floor) was significantly lower than to respective flat surfaces.
• No significant difference in bond strength was observed between cavity wall and cavity floor for Clearfil SE Bond and Clearfil tri-S Bond.

Conclusions:

• Dentin C-factor significantly affects resin composite bond strength, irrespective of the adhesive system.
• Bond strength is consistently higher for flat wall dentin compared to flat floor dentin.
• Self-etching systems promote uniform bonding to cavity wall and floor, while total-etch systems may reduce bond strength to the cavity floor.