Related Experiment Video
Updated: Feb 23, 2026

Shrinkage of Dental Composite in Simulated Cavity Measured with Digital Image Correlation
Published on: July 21, 2014
Survival of Direct Posterior Composites With and Without a Bulk Fill Base
C McGuirk1, F Hussain1, B J Millar1
1Kings College, London.
Objectives:
Direct composite restorations are increasingly popular and a flowable bulk-fill base material (SDR, Dentsply) claims to minimise stress through a more flexible polymerisation process. This retrospective audit of restorations placed in general practice compares SDR based restorations with conventional composite restorations.
Methods:
Restorations were all placed by one operator using a similar clinical technique and were audited as Group G, placed with a conventional layering composite (G-aenial, GC) and Group S which had a bulk-fill base of SDR (Dentsply) and then were covered with G-aenial (GC). Data regarding survival, post-operative sensitivity and mode of failure were recorded and analysed.
Results:
In total 54 Group S restorations and 71 Group G restorations were followed for a minimum of 24 months. Group S had a 92.6% survival and Group G 93%. Group S was more prone to failure by tooth fracture (p=0.033). In both groups failure was more likely in larger cavities, in both those with an increased number of surfaces (p⟨0.001) and cuspal coverage (p=0.004).
Conclusions:
There appears to be similar survival of the two techniques in the short-term although there were significantly more tooth fractures in teeth restored with SDR.

