Experimental Research On The Adaptation Of Two Different Cast Full Crowns

BackgroundThe main reason of adhesion dissolved, secondary caries produced and restorations felled out etc is the poor fitness of restorations. The regime of poor adaptation of prosthetic is influenced by so many facts. For example:the appearance of preparation, surface roughness of rotation, times or ways to clean the oxide layer and so on. All the things above are technically which could be control by human, our experiment will try to take out these in order to find the effect by metal inherent reason.ObjectiveThis experiment is to san the slices of silicon rubber which instead of the gap between resinous dies and cast full crowns, then use the computer photo software to calculate and contrast two stances though figures by measured. Expecting that experiment will give some proposal of material selection for doctors and patients. In the test we will try to validate is there a convenient way to check the fitness of cast crown for doctors and technicians to quickly measure crown’s accuracy.MethodsThe30resinous dies of NISSIN will select mandibular first molar, then divided them into two groups randomly which will used to make cast crowns by Au-Pd alloys and Ni-Cr alloys. Get the slices of silicon rubber which instead of the gap between resinous dies and cast full crowns. Scanning the slices of silicon rubber to test mean value of the marginal gap distance, the internal gap distance and the occlusal gap distance on the picture. Counting the scale by the ways of contrast real distance of ruler and scan the length of ruler under same condition as before. then gain the authentic range of gap. Results1. The mean value of marginal gap:Ni-Cr alloys full crowns (95.7600±2.44476) μm, Au-Pd alloys full crowns (79.6667±2.64485)μm.2. The mean value of internal gap:Ni-Cr alloys full crowns (68.2400±3.10824)μm, Au-Pd alloys full crowns (52.2267±2.93001)μm3. The mean value of occlusal gap:Ni-Cr alloys full crowns (188.6000±4.53321)μm, Au-Pd alloys full crowns (148.8733±2.99892)μmConclusionsThe fitness of Au-Pd alloys cast full crowns have a more obvious advantage than Ni-Cr alloys cast full crowns.