Recycling acetal resin as material for dental

Background: To reduce environmental biohazards, technicians should be educated with safe biological waste disposal procedures and dental material recycling. Objective: To evaluate the impact strength and apparent porosity of re-injection acetal resin in different percentages or several times. Materials and methods: Sixty specimens were prepared with dimension (65mm×10 mm×2 mm) length, width and thickness for impact test and fifty-four-disc specimens with dimensions (20±1 mm in diameter x 0.5 mm in thickness) for apparent porosity test and injection according to the manufacture’s instruction for acetal resin as denture base materials. The first group represent control group with (100% New) and other five groups as experimental groups. The old material is preparation by acetal sprue is collected and cutting by cutter and re-injection with new acetal resin. Results: After comparing the results of impact strength a significant difference in the impact strength of control (80.75±9.133) and re-injection groups. On other hand significant differences of apparent porosity test of all study groups. Conclusion: Recycling acetal resin as denture base that reduces the impact strength when increase using old material, on other hand the apparent porosity is increase after one month and decrease after one day.