Tensile bond strength to primary dentin after different etching times

Area of Science:

• Dental Materials Science
• Adhesive Dentistry
• Pediatric Dentistry

Background:

• Primary dentin presents unique challenges for adhesive procedures due to its structural and compositional differences from permanent dentin.
• Optimizing etching protocols is crucial for achieving durable resin-dentin bonds in pediatric patients.

Purpose of the Study:

• To evaluate the in vitro impact of varying phosphoric acid etching times on the tensile bond strength of resin composites to primary dentin.
• To determine the optimal etching duration for primary dentin to maximize bond strength and minimize clinical chair time.

Main Methods:

• Forty primary molar crowns were prepared and divided into four groups based on etching times (7, 10, 15, and 20 seconds) using 35% phosphoric acid gel.
• Adhesive system application and resin composite buildup were performed on a standardized 3-mm diameter bonding site.
• Tensile bond strength was assessed after 24 hours using one-way ANOVA and Tukey's post-hoc test.

Main Results:

• The mean tensile bond strengths (MPa) were: 7 seconds (10.04 ± 3.30), 10 seconds (7.78 ± 4.49), 15 seconds (8.78 ± 2.96), and 20 seconds (7.60 ± 1.91).
• No statistically significant differences in bond strength were observed among the different etching times.
• The shortest etching time (7 seconds) yielded the highest mean bond strength.

Conclusions:

• A 7-second etching time is effective for achieving optimal tensile bond strength to primary dentin.
• Utilizing a shorter etching time can significantly reduce chair time, a critical advantage in pediatric dentistry.
• The findings support the use of a 7-second etching protocol for improved efficiency and bond durability in primary teeth restorations.