Title: 0881 - Effects of Simulated Gastric Acids on Mechanical Properties of CAD/CAM Resin Composites


Bebek Oguz Ahmet (Presenter)
Medipol University School of Dentistry

Roda Seseogullari-Dirihan, University of Turku
Kaveh NIK Jamal, University of Turku
Mustafa Mutluay, University of Turku
Arzu Tezvergil-Mutluay, University of Turku


Objectives: To evaluate the effects of simulated gastric juice on CAD/CAM resin composites by means of four-point flexure testing hardness evaluations.

Methods: One hundred and twenty rectangular beams (2x2x12 mm) were sectioned from the CAD-CAM blocks (Lava Ultimate (LU), Grandio (GR) and Cerasmart (CS)) and polished and sintered. E.max specimens were used as control. The beams were polished and were randomly divided into three groups (n=10/group); 1) No treatment; 2) Erosive challenges in a simulated gastric juice (pH = 1.2, 24 hrs , 37 °C ); 3) Erosive challenge in a Trypsin based simulated gastric solution, (pH=7.4, 24 hrs, 37 °C). The beams were subjected to quasi-static four-point flexure testing to failure at the baseline (no treatment group) or after erosive challenges. Vickers microhardness and surface roughness (Ra) were also assessed before (baseline) and after erosive challenge. Morphological analysis was obtained using scanning electron microscopy (SEM). Statistical analysis was performed using two-way ANOVA Holm-Sidak test (α = 0.05).

Results: The baseline flexural strength of the composite CAD-CAM beams ranged between 195,8 (±54.2) MPa for GR and 145,9 (±23,9) MPa LU. Significant difference was observed among the baseline flexural strength of the beams ( p<0.05). The four-point flexure strength and microhardness was not affected by the acidic challenge (p >0.05). However, after acid exposure a significant increase in Ra values were obtained compared to baseline (p<0.05) as confirmed by SEM imaging.

Conclusions: The acidic conditions tested in the present study changed the surface roughness of the CAD-CAM blocks but not their mechanical properties.

This abstract is based on research that was funded entirely or partially by an outside source:
This study was funded by the grant #296653 from the Academy of Finland to AT-M (PI) and EVO funding #13140 of Turku University Hospital to AT-M (PI).

Disclosure Statement:
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: NONE