Mechanical Properties Of Resin Composite Containing Calcium Phosphate And Polylysine

Objectives: The aim of this study was to assess the degree of monomer conversion (DC) and biaxial flexural strength (BFS)/modulus (BFM) of novel dental composites containing calcium phosphate and polylysine (Renewal MI, MI). The results were compared with a commercial resin composite (Filtek Z350 XT, Z350), conventional glass ionomer cements (EQUIA Forte, EQ; Fuji VII, F7), and resin-modified glass ionomer cement (Fuji II LC, F2).
Methods: DC of MI, Z350, and F2 after light-curing for 20 s were determined using ATR-FTIR (n=8). BFS/BFM of all materials after immersion in artificial saliva for 24 h were assessed using a ball-on-ring testing jig under a universal testing machine (n=8). Data were analyzed using one-way ANOVA followed by Tukey's multiple comparison test. The significance level was set at p=0.05.
Results: Mean DC of MI (57%) was comparable to that of Z350 (61%)(p=0.168). DCs of these materials were significantly lower than that of F2 (98%)(p<0.05). The highest BFS was obtained from Z350 (268 MPa). The BFS of MI (135 MPa) was comparable to that of F2 (109 MPa) but higher than EQ (50 MPa) and F7 (35 MPa). Additionally, MI exhibited a comparable BFM (3.2 GPa) to EQ (3.8 GPa) and F2 (3.6 GPa)(p>0.05). However, the modulus of MI was lower than Z350 (4.5 GPa).
Conclusions: The novel resin composite containing calcium phosphate and polylysine showed a comparable DC but lower strength than the commercial resin composite. The strength values were still comparable to or higher than that of glass ionomer cements. These properties could potentially help reduce secondary caries occurred with resin composite restorations.