ABSTRACT
INRTODUCTION: Microwave irradiation is considered an effective way to decontaminate complete dentures. The impact of microwave disinfection on resin dentures manufactured by CAD/CAM technologies was unclear.
OBJECTIVES: This study was carried out to assess the influence of frequent use of microwave disinfection on flexural strength and dimensional stability of CAD/CAM milled and 3D-printed denture resin.
MATERIALS AND METHODS: 40 rectangular samples with dimensions of (65 mm× 10 mm× 3.3 mm) were designed from each type of resin for flexural strength test and 10 samples with dimensions of (32 mm × 10 mm× 2.5 mm) from each type of materials for dimensional stability test. Samples were irradiated by microwave oven with power of 650 watts for 3 min. The disinfection cycle was repeated for 40, 80, 120 cycles. Flexural strength was measured by Universal testing machine. Dimensional changes were determined by digital caliper calibrated to 0.03 mm.
RESULTS: Differences in flexural strength amongst milled groups were insignificant while there was significant decrease amongst 3D printed groups. No significant differences were noticed in dimensions of specimens in both types of materials.
CONCLUSION: Microwave disinfection was a safe technique for 120 cycles that had no effect on flexural strength of CAD/CAM milled resin. However, an adverse effect was noticed on the flexural strength of 3D-printed resin. There was no effect on dimensional stability of both types of resin materials
KEY WORDS: CAD/CAM, 3D-printed, microwave disinfection, flexural strength, dimensional stability.