IADR Abstract Archives
Marginal Accuracy of CAD/CAM PMMA Crowns Fabricated by Photogrammetry Scanning method
Objectives: To assess the marginal accuracy of provisional CAD/CAM PMMA crowns fabricated by two-dimensional image-based rendering (IBR) photogrammetry scanning method.
Methods: Maxillary central incisor was anatomically prepared, from which 10 epoxy resin dies were fabricated. The dies were scanned using two different scanning methods: extraoral desktop scanner and Photogrammetry scanning. For the latter the dies were scanned by capturing standardized photos using a professional digital single reflex (DSLR) camera for photo acquisition. Photography technique was standardized using a custom-made computer controlled device to ensure adequate overlap between acquired photos, further rendering of photos was done using specialized photogrammetry software. Produced standardized tessellation Language (STL) files from both scanning methods were used for fabrication of CAD/CAM Polymethylmethacrylate (PMMA) crowns. Mean vertical marginal gap of crowns fabricated by both scanning methods was measured using stereomicroscope at 20 equidistant points (5 points in each surface), and results were statistically analysed using paired t-test.
Results: Mean of marginal gap for crowns fabricated using photogrammetry scanning was (99.6 µ) , while for crowns fabricted using desktop extraoral scanner was (106.3 µ).No statistically significant difference was found between marginal gap distances measurement by extraoral scanner and photogrammetry scanning method (p>0.05). The marginal accuracy results were within the clinically acceptable range below 120 µ.
Conclusions: Photogrammetry scanning using image-based rendering can be an affordable and reliable method for fabrication of CAD/CAM crowns with proper marginal accuracy.
Methods: Maxillary central incisor was anatomically prepared, from which 10 epoxy resin dies were fabricated. The dies were scanned using two different scanning methods: extraoral desktop scanner and Photogrammetry scanning. For the latter the dies were scanned by capturing standardized photos using a professional digital single reflex (DSLR) camera for photo acquisition. Photography technique was standardized using a custom-made computer controlled device to ensure adequate overlap between acquired photos, further rendering of photos was done using specialized photogrammetry software. Produced standardized tessellation Language (STL) files from both scanning methods were used for fabrication of CAD/CAM Polymethylmethacrylate (PMMA) crowns. Mean vertical marginal gap of crowns fabricated by both scanning methods was measured using stereomicroscope at 20 equidistant points (5 points in each surface), and results were statistically analysed using paired t-test.
Results: Mean of marginal gap for crowns fabricated using photogrammetry scanning was (99.6 µ) , while for crowns fabricted using desktop extraoral scanner was (106.3 µ).No statistically significant difference was found between marginal gap distances measurement by extraoral scanner and photogrammetry scanning method (p>0.05). The marginal accuracy results were within the clinically acceptable range below 120 µ.
Conclusions: Photogrammetry scanning using image-based rendering can be an affordable and reliable method for fabrication of CAD/CAM crowns with proper marginal accuracy.