How should composite be layered to reduce shrinkage stress: incremental or bulk filling?
OBJECTIVE
The purpose of this study was to determine the effect of different layering techniques on cuspal deflection in direct composite restorations.


METHODS
Aluminum blocks were used to prepare MOD cavities divided into three groups. Each cavity was restored with composite using three different filling techniques. Group 1 was filled in bulk, group 2 was restored by a horizontal increment technique, and group 3 by an oblique increment technique. Cuspal deflection was measured with LVDT probes and compared among groups using ANOVA and Scheffe's post hoc test (alpha = 0.05).


RESULTS
The cuspal deflections in groups 1-3 were 21.6+/-0.90 microm, 19.3+/-0.73 microm and 18.4+/-0.63 microm, respectively. The bulk filling technique yielded significantly more cuspal deflection than the incremental filling techniques, while there was no significant difference between the horizontal and oblique increment methods.


CONCLUSIONS
Cuspal deflection resulting from polymerization shrinkage can be reduced by incremental filling techniques to obtain optimal outcomes in clinical situations.
Park
Junkyu
J
Department of Conservative Dentistry and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, South Korea.
Chang
Juhea
J
Ferracane
Jack
J
Lee
In Bog
IB
D003188:Composite Resins / Q000008:administration & dosage*; D018772:Dental Marginal Adaptation; D003793:Dental Restoration, Permanent / Q000379:methods*; D003799:Dental Stress Analysis; D044367:Phase Transition; D011897:Random Allocation
D003188:Composite Resins