Core build-up resin composites: an in-vitro comparative study

Abstract

Aim

Resin composite (RC) are commonly used under full crowns. However, independent information is lacking to guide practitioners regarding core RC material selection. This study aimed at comparing the flexural properties of a large selection of commercially-available core build-up RCs (CBU-RC), either light-, self- or dual-cure, to conventional light-cure RCs.

Methods

RCs were injected into a 25 × 2×2mm Teflon mold, and either light-cured during 20 s (materials with claimed light-cure characteristics) or covered by aluminum during 10 min (dual- and self-cure CBU-RCs). They were subjected after a one-week water storage at 37.5 °C to three-point bending, and Flexural modulus (E_flex) and Flexural Strength (σ_f) were calculated (n = 20). Thermogravimetric analysis (n = 3) was performed to determine inorganic filler content (%).

Results

For dual-cure CBU-RCs, both RC (p < .0001) and light-curing (p = .0007) had a significant influence on E_flex, while only RC was significant for σ_f (p < .0001). Between all conventional RCs and CBU-RCs, significant differences were observed (p < .0001), both regarding E_flex and σ_f, with values ranging from 3.9 to 15.5 GPa and from 76 to 130.3 MPa, respectively. Higher E_flex values were observed for light-cure RCs than for self- and dual-cure ones, while no clear trend was noticed regarding σ_f. Good linear correlation was found between inorganic filler content and E_flex (R²=0.85, p < .0001), but not with σ_f (R²=0.08, p = .1609).

Conclusion

This work demonstrated a positive influence of light-curing on dual-cure CBU-RC’s E_flex. It also highlighted large differences in flexural properties (especially E_flex) among the investigated materials, questioning the use of some CBU-RCs as dentin replacement in case of large tissue loss.

Keywords:

• core build-up
• resin composite
• dual cure
• flexural modulus
• flexural strength

Acknowledgments

The authors would like to thank all the manufacturers for supporting this study by supplying the investigated materials: 3M ESPE, Dentsply, DMG, GC, Ivoclar-Vivadent, Kuraray, Septodont, Ultradent and VOCO.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

VOCO covered some of the operating costs of the study.