Effect of contamination of bulk-fill flowable resin composite with different contaminants during packing on its surface microhardness and compressive strength: in vitro study

Abstract

Background Proper isolation and restoration of class V subgingival cavities are technique sensitive, thus the resin composite restoration is liable to contamination. This in vitro study was conducted to evaluate the surface microhardness and compressive strength of bulk-fill flowable resin composite after being contaminated during its packing. Methods Resin composite discs were prepared using split mold. The contaminated specimens were allocated into four groups (n = 20) according to the contaminant used: hemostatic agent (Group 1), alcohol (Group 2), artificial saliva (Group 3) and powdered gloves (Group 4). The non-contaminated specimens (n = 20) were used as control group. The surface microhardness and compressive strength of each group were tested 1-day post-photocuring (n = 5) and 1 month post-photocuring (n = 5). Values were presented as mean, standard deviation values and confidence intervals. Results The surface microhardness of all groups didn’t show a significant difference for different tested groups except for alcohol which showed a significant reduction on surface microhardness compared to control at 1 day post-photocuring (p = 0.001). The highest compressive strength mean values at 1 day and 1 month post-photocuring were recorded in control groups (110.42 MPa and 172.87 MPa respectively), followed by alcohol groups, then hemostatic agent groups, followed by artificial saliva with the least value recorded in powdered gloves groups (56.71 MPa and 49.5 MPa respectively). Conclusions Contamination of bulk-fill flowable resin composite with hemostatic agent, alcohol, artificial saliva, or powdered gloves during its packing decreased its compressive strength after 1 month post-photocuring rather than affecting its surface microhardness.

In Vitro Evaluation of Mechanical, Surface, and Optical Properties of Restorative Materials Applied with Different Techniques

“…Most chewing forces are compressive in nature [55]. Therefore, compressive strength is an essential parameter for restorative materials [56].…”

Mouthwashes: Surface Hardness and Accuracy of Dual-cured Visible Light-Cured Composite

“…The restorative materials in the oral cavity should have long-term durability with an adequate hardness to resist indentation or penetration (6,10) . This may be associated with the strength, rigidity, and intraoral softening of this material in service (11,12) . Also, many factors could contribute to the hardness of such materials as the chemical composition of the material itself, the material type, surface treatment, degree of conversion, storage time, and the chemistry of storage media (11,13) .…”

“…This may be associated with the strength, rigidity, and intraoral softening of this material in service (11,12) . Also, many factors could contribute to the hardness of such materials as the chemical composition of the material itself, the material type, surface treatment, degree of conversion, storage time, and the chemistry of storage media (11,13) . Clinically, the composite degradation might not relate to a singular factor or chemical substance.…”