Fracture resistance of pulpotomized and composite‑restored primary molars: Incremental versus bulk‑fill techniques

Abstract

Background: The aim of this study was to assess the fracture resistance of pulpotomized primary
molars restored with incremental and bulk‑fill composite application techniques.
Materials and Methods: In this in‑vitro experimental study, 36 extracted primary molars were
nonrandomly (selectively) divided into three groups of 12 each. All teeth underwent conventional
pulpotomy treatment, and mesio‑occluso‑distal cavities were prepared in such a way that the
buccolingual width of the preparation was two‑thirds of the intercuspal distance, and the depth of the
buccal and lingual walls was 4 mm. The teeth were then restored as follows: Group 1 (control) was
restored with amalgam, Group 2 was restored with Tetric N‑Ceram composite using the incremental
technique, and Group 3 was restored with Tetric N‑Ceram composite using the bulk‑fill technique.
The restored teeth were subjected to thermocycling and then underwent fracture resistance testing
in a universal testing machine at a crosshead speed of 1 mm/min. Fracture resistance of groups was
compared using the one‑way ANOVA and Tukey’s honestly significant difference test.
Results: The mean fracture resistance was 1291.47 ± 603.88 N in the amalgam, 1283.08 ± 594.57 N
in the Tetric N‑Ceram incremental, and 1939.06 ± 134.47 N in the Tetric N‑Ceram bulk‑fill group. The
difference in this regard between Group 3 and Groups 1 and 2 was statistically significant (P = 0.019
and P = 0.035, respectively).
Conclusion: Bulk‑fill composite is recommended for reinforcing the remaining tooth structure
after the primary molar pulpotomy procedure. Time‑saving characteristics of this material are
clinically important for reducing appointment time for children.
Key Words: Bulk‑fill composite, conventional composite, fracture resistance, primary molar,pulpotomy