Bulk-filled posterior resin restorations based on stress-decreasing resin technology: a randomized, controlled 6-year...

Area of Science:

• Dentistry
• Dental Materials
• Restorative Dentistry

Background:

• Direct posterior restorations are crucial in modern dentistry.
• Traditional resin composite layering requires meticulous technique and time.
• Bulk-fill techniques offer potential advantages in placement efficiency.

Purpose of the Study:

• To compare the 6-year clinical performance of a flowable resin composite bulk-fill technique versus a conventional layering technique for posterior restorations.
• To evaluate intraindividual success rates and failure modes of both techniques.

Main Methods:

• A randomized, intraindividual study design was employed with 38 pairs of Class II and 15 pairs of Class I restorations in 38 adults.
• One cavity received a flowable bulk-fill composite (SDR) with a nanohybrid overlay, while the contralateral cavity received conventional nanohybrid composite in 2mm increments.
• Single-step self-etch adhesive (Xeno V) was used for all restorations, evaluated annually for 6 years using modified USPHS criteria.

Main Results:

• After 6 years, 72 Class II and 26 Class I restorations were evaluated.
• Overall success rate was 93.9% with an annual failure rate (AFR) of 1.0% for both techniques.
• Class II restorations had an AFR of 1.4% in both groups, while Class I restorations showed 0% AFR.
• The primary reason for failure in both groups was resin composite fracture.

Conclusions:

• Flowable resin composite bulk-fill technique shows comparable long-term clinical performance to conventional layering for posterior restorations.
• Both techniques exhibit similar failure rates and modes, with fracture being the predominant issue.
• Bulk-fill composites offer a viable alternative for efficient posterior restorations without compromising longevity over 6 years.